Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

680 files changed, 52091 insertions, 0 deletions

diff --git a/l10n-cy/browser/branding/official/brand.dtd b/l10n-cy/browser/branding/official/brand.dtd
new file mode 100644
index 0000000000..d094ad0f8d
--- /dev/null
+++ b/l10n-cy/browser/branding/official/brand.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  brandShorterName      "Firefox">
+<!ENTITY  brandShortName        "Firefox">
+<!ENTITY  brandFullName         "Mozilla Firefox">
+<!-- LOCALIZATION NOTE (brandProductName):
+   This brand name can be used in messages where the product name needs to
+   remain unchanged across different versions (Nightly, Beta, etc.). -->
+<!ENTITY  brandProductName      "Firefox">
diff --git a/l10n-cy/browser/branding/official/brand.ftl b/l10n-cy/browser/branding/official/brand.ftl
new file mode 100644
index 0000000000..859a03952d
--- /dev/null
+++ b/l10n-cy/browser/branding/official/brand.ftl
@@ -0,0 +1,37 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Firefox Brand
+##
+## Firefox must be treated as a brand, and kept in English.
+## It cannot be:
+## - Declined to adapt to grammatical case.
+## - Transliterated.
+## - Translated.
+##
+## Reference: https://www.mozilla.org/styleguide/communications/translation/
+
+## Firefox and Mozilla Brand
+##
+## Firefox and Mozilla must be treated as a brand.
+##
+## They cannot be:
+## - Transliterated.
+## - Translated.
+##
+## Declension should be avoided where possible, leaving the original
+## brand unaltered in prominent UI positions.
+##
+## For further details, consult:
+## https://mozilla-l10n.github.io/styleguides/mozilla_general/#brands-copyright-and-trademark
+
+-brand-shorter-name = Firefox
+-brand-short-name = Firefox
+-brand-full-name = Mozilla Firefox
+# This brand name can be used in messages where the product name needs to
+# remain unchanged across different versions (Nightly, Beta, etc.).
+-brand-product-name = Firefox
+-vendor-short-name = Mozilla
+trademarkInfo = Nodau masnachu'r Mozilla Foundation yw Firefox a logos Firefox.
diff --git a/l10n-cy/browser/branding/official/brand.properties b/l10n-cy/browser/branding/official/brand.properties
new file mode 100644
index 0000000000..568f227d4c
--- /dev/null
+++ b/l10n-cy/browser/branding/official/brand.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+brandShorterName=Firefox
+brandShortName=Firefox
+brandFullName=Mozilla Firefox
+# LOCALIZATION NOTE(brandProductName):
+# This brand name can be used in messages where the product name needs to
+# remain unchanged across different versions (Nightly, Beta, etc.).
+brandProductName=Firefox
+vendorShortName=Mozilla
+
+syncBrandShortName=Sync
diff --git a/l10n-cy/browser/browser/aboutCertError.ftl b/l10n-cy/browser/browser/aboutCertError.ftl
new file mode 100644
index 0000000000..946e70764f
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutCertError.ftl
@@ -0,0 +1,126 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+cert-error-intro = Mae { $hostname } yn defnyddio tystysgrif diogelwch annilys.
+
+cert-error-mitm-intro = Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau, sy'n cael eu cyhoeddi gan awdurdodau tystysgrifau.
+
+cert-error-mitm-mozilla = Mae { -brand-short-name } yn cael ei gefnogi gan Mozilla y corff dim-er-elw, sy'n gweinyddu storfa awdurdod tystysgrifau (CA) cwbl agored. Mae'r storfa'n cynorthwyo i sicrhau fod awdurdodau tystysgrif yn dilyn ymarfer gorau ar gyfer diogelwch defnyddwyr.
+
+cert-error-mitm-connection = Mae { -brand-short-name } yn defnyddio storfa CA Mozilla i wirio bod cysylltiad yn ddiogel, yn hytrach na thystysgrifau wedi eu cyflenwi gan system weithredu'r defnyddiwr. Felly, os yw rhaglen gwrth-firws neu rwydwaith yn rhyng-gipio cysylltiad â thystysgrif diogelwch a gyhoeddwyd gan CA nad yw yn storfa CA Mozilla, mae'n ystyried bod y cysylltiad yn anniogel.
+
+cert-error-trust-unknown-issuer-intro = Gall fod rhywun yn ceisio efelychu'r wefan a pheidiwch â mynd yn eich blaen.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+cert-error-trust-unknown-issuer = Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau. Nid yw { -brand-short-name } yn ymddiried yn { $hostname } gan nad yw ei gyhoeddwr tystysgrifau'n hysbys, mae'r dystysgrif wedi ei llofnodi ganddo'i hun neu nid yw'r gweinydd yn anfon y tystysgrifau rhyngol cywir.
+
+cert-error-trust-cert-invalid = Nid oes modd ymddiried yn y dystysgrif am ei fod wedi rhyddhau tystysgrif CA annilys.
+
+cert-error-trust-untrusted-issuer = Nid oes modd ymddiried yn y dystysgrif oherwydd nad oes modd ymddiried yn ei chyhoeddwr.
+
+cert-error-trust-signature-algorithm-disabled = Nid oes ymddiriedaeth i'r dystysgrif gan ei fod wedi ei lofnodi gan ddefnyddio algorithm llofnod sydd wedi ei analluogi am nad yw'r algorithm yn anniogel.
+
+cert-error-trust-expired-issuer = Nid oes modd ymddiried yn y dystysgrif oherwydd bod y dystysgrif ryddhau wedi dod i ben.
+
+cert-error-trust-self-signed = Nid oes modd ymddiried yn y dystysgrif am ei fod wedi ei hunanlofnodi.
+
+cert-error-trust-symantec = Nid yw tystysgrifau a gyhoeddwyd gan GeoTrust, RapidSSL, Symantec, Thawte, a VeriSign bellach yn cael eu hystyried yn ddiogel oherwydd nad oedd yr awdurdodau tystysgrif hyn yn dilyn arferion diogelwch yn y gorffennol.
+
+cert-error-untrusted-default = Nid yw'r dystysgrif yn dod o fan gellir ymddiried ynddo.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+cert-error-domain-mismatch = Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau. Nid yw { -brand-short-name } yn ymddiried yn y wefan hon gan ei fod yn defnyddio tystysgrif nad yw'n ddilys ar gyfer { $hostname }.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+# $alt-name (String) - Alternate domain name for which the cert is valid.
+cert-error-domain-mismatch-single = Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau. Nid yw { -brand-short-name } yn ymddiried yn y wefan hon gan ei fod yn defnyddio tystysgrif nad yw'n ddilys ar gyfer { $hostname }. Dim ond ar gyfer <a data-l10n-name="domain-mismatch-link">{ $alt-name }</a> mae'r dystysgrif yn ddilys.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+# $alt-name (String) - Alternate domain name for which the cert is valid.
+cert-error-domain-mismatch-single-nolink = Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau. Nid yw { -brand-short-name } yn ymddiried yn y wefan hon gan ei fod yn defnyddio tystysgrif nad yw'n ddilys ar gyfer { $hostname }. Dim ond ar gyfer { $alt-name } mae'r dystysgrif yn ddilys.
+
+# Variables:
+# $subject-alt-names (String) - Alternate domain names for which the cert is valid.
+cert-error-domain-mismatch-multiple = Mae gwefannau yn profi eu hunaniaeth trwy dystysgrifau. Nid yw { -brand-short-name } yn ymddiried yn y wefan hon oherwydd ei fod yn defnyddio tystysgrif nad yw'n ddilys ar gyfer { $hostname }. Mae'r dystysgrif yn ddilys yn unig ar gyfer yr enwau canlynol: { $subject-alt-names }
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+# $not-after-local-time (Date) - Certificate is not valid after this time.
+cert-error-expired-now = Mae gwefannau yn profi eu hunaniaeth trwy dystysgrifau, sy'n ddilys am gyfnod penodol. Daeth y dystysgrif ar gyfer { $hostname } i ben ar { $not-after-local-time }.
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+# $not-before-local-time (Date) - Certificate is not valid before this time.
+cert-error-not-yet-valid-now = Mae gwefannau yn profi eu hunaniaeth trwy dystysgrifau, sy'n ddilys am gyfnod penodol. Ni fydd y dystysgrif ar gyfer { $hostname } yn ddilys tan { $not-before-local-time }.
+
+# Variables:
+# $error (String) - NSS error code string that specifies type of cert error. e.g. unknown issuer, invalid cert, etc.
+cert-error-code-prefix-link = Cod gwall: <a data-l10n-name="error-code-link">{ $error }</a>
+
+# Variables:
+# $hostname (String) - Hostname of the website with cert error.
+cert-error-symantec-distrust-description = Mae gwefannau yn profi eu hunaniaeth trwy dystysgrifau, sy'n cael eu cyhoeddir gan awdurdodau tystysgrif. Nid yw'r mwyafrif o borwyr bellach yn ymddiried mewn tystysgrifau a gyhoeddir gan GeoTrust, RapidSSL, Symantec, Thawte, a VeriSign. Mae { $hostname } yn defnyddio tystysgrif gan un o'r awdurdodau hyn ac felly nid oes modd profi hunaniaeth y wefan.
+
+cert-error-symantec-distrust-admin = Gallwch hysbysu gweinyddwr y wefan am y broblem hon.
+
+# Variables:
+# $hasHSTS (Boolean) - Indicates whether HSTS header is present.
+cert-error-details-hsts-label = Diogelwch Trosglwyddo Llym HTTP: { $hasHSTS }
+
+# Variables:
+# $hasHPKP (Boolean) - Indicates whether HPKP header is present.
+cert-error-details-key-pinning-label = Pinio Allwedd Cyhoeddus HTTP: { $hasHPKP }
+
+cert-error-details-cert-chain-label = Cadwyn tystysgrif:
+
+open-in-new-window-for-csp-or-xfo-error = Agor Gwefan mewn Ffenestr Newydd
+
+# Variables:
+# $hostname (String) - Hostname of the website blocked by csp or xfo error.
+csp-xfo-blocked-long-desc = Er mwyn amddiffyn eich diogelwch, ni fydd { $hostname } yn caniatáu i { -brand-short-name } ddangos y dudalen os yw gwefan arall wedi'i mewnblannu ynddi. I weld y dudalen hon, bydd angen i chi ei hagor mewn ffenestr newydd.
+
+## Messages used for certificate error titles
+
+connectionFailure-title = Methu cysylltu
+deniedPortAccess-title = Mae'r cyfeiriad wedi ei gyfyngu
+# "Hmm" is a sound made when considering or puzzling over something.
+# You don't have to include it in your translation if your language does not have a written word like this.
+dnsNotFound-title = Hmm. Rydym yn cael trafferth canfod y wefan honno.
+fileNotFound-title = Heb ganfod ffeil
+fileAccessDenied-title = Mae mynediad i'r ffeil wedi ei wrthod
+generic-title = Wps.
+captivePortal-title = Mewngofnodi i'r rhwydwaith
+# "Hmm" is a sound made when considering or puzzling over something.
+# You don't have to include it in your translation if your language does not have a written word like this.
+malformedURI-title = Hmm. Dyw'r cyfeiriad yna ddim yn edrych yn iawn.
+netInterrupt-title = Cafodd y cysylltiad ei darfu
+notCached-title = Daeth y Ddogfen i Ben
+netOffline-title = Modd all-lein
+contentEncodingError-title = Gwall Amgodio Cynnwys
+unsafeContentType-title = Math Anniogel o ffeil
+netReset-title = Cafodd y cysylltiad ei ailosod
+netTimeout-title = Mae cyfnod y cyswllt wedi dod i ben
+unknownProtocolFound-title = Heb ddeall y cyfeiriad
+proxyConnectFailure-title = Mae'r gweinydd dirprwy yn gwrthod cysylltiadau
+proxyResolveFailure-title = Methu canfod y gweinydd dirprwyol
+redirectLoop-title = Nid yw'r dudalen yn ailgyfeirio'n iawn
+unknownSocketType-title = Ymateb annisgwyl gan y gweinydd
+nssFailure2-title = Methodd y Cysylltiad Diogel
+csp-xfo-error-title = Nid yw { -brand-short-name } yn Gallu Agor y Dudalen hon
+corruptedContentError-title = Gwall Cynnwys Llygredig
+remoteXUL-title = XUL pell
+sslv3Used-title = Methu Cysylltu'n Ddiogel
+inadequateSecurityError-title = Nid yw eich cysylltiad yn ddiogel
+blockedByPolicy-title = Tudalen wedi'i Rhwystro
+clockSkewError-title = Mae cloc eich cyfrifiadur yn anghywir
+networkProtocolError-title = Gwall Protocol Rhwydwaith
+nssBadCert-title = Rhybudd: Risg Diogelwch Posibl o'ch Blaen
+nssBadCert-sts-title = Peidiwch Cysylltu: Mater Diogelwch Posib
+certerror-mitm-title = Mae Meddalwedd yn Rhwystro { -brand-short-name } Rhag Cysylltu'n Ddiogel i'r Wefan Hon
diff --git a/l10n-cy/browser/browser/aboutConfig.ftl b/l10n-cy/browser/browser/aboutConfig.ftl
new file mode 100644
index 0000000000..67d0d2154d
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutConfig.ftl
@@ -0,0 +1,54 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## These strings appear on the warning you see when first visiting about:config.
+
+about-config-intro-warning-title = Byddwch Ofalus
+about-config-intro-warning-text = Gall newid dewisiadau ffurfweddiad uwch effeithio ar berfformiad neu ddiogelwch { -brand-short-name }.
+about-config-intro-warning-checkbox = Rhybuddiwch fi pan fyddaf yn ceisio mynd at y dewisiadau hyn
+about-config-intro-warning-button = Derbyn y Perygl a Pharhau
+
+
+
+##
+
+# This is shown on the page before searching but after the warning is accepted.
+about-config-caution-text = Gall newid dewisiadau ffurfweddiad uwch effeithio ar berfformiad neu ddiogelwch { -brand-short-name }.
+
+about-config-page-title = Dewisiadau Uwch
+
+about-config-search-input1 =
+    .placeholder = Enw dewis chwilio
+about-config-show-all = Dangos Popeth
+
+about-config-pref-add-button =
+    .title = Ychwanegu
+about-config-pref-toggle-button =
+    .title = Toglo
+about-config-pref-edit-button =
+    .title = Golygu
+about-config-pref-save-button =
+    .title = Cadw
+about-config-pref-reset-button =
+    .title = Ailosod
+about-config-pref-delete-button =
+    .title = Dileu
+
+## Labels for the type selection radio buttons shown when adding preferences.
+
+about-config-pref-add-type-boolean = Boole
+about-config-pref-add-type-number = Rhif
+about-config-pref-add-type-string = Llinyn
+
+## Preferences with a non-default value are differentiated visually, and at the
+## same time the state is made accessible to screen readers using an aria-label
+## that won't be visible or copied to the clipboard.
+##
+## Variables:
+##   $value (String): The full value of the preference.
+
+about-config-pref-accessible-value-default =
+    .aria-label = { $value } (default)
+about-config-pref-accessible-value-custom =
+    .aria-label = { $value } (custom)
diff --git a/l10n-cy/browser/browser/aboutDialog.ftl b/l10n-cy/browser/browser/aboutDialog.ftl
new file mode 100644
index 0000000000..81fdc485da
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutDialog.ftl
@@ -0,0 +1,46 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+aboutDialog-title =
+    .title = Ynghylch { -brand-full-name }
+releaseNotes-link = Beth sy'n newydd
+update-checkForUpdatesButton =
+    .label = Gwirio am ddiweddariadau
+    .accesskey = G
+update-updateButton =
+    .label = Ailgychwyn i ddiweddaru { -brand-shorter-name }
+    .accesskey = A
+update-checkingForUpdates = Gwirio am ddiweddariadau…
+update-downloading = <img data-l10n-name="icon"/>Llwytho'r diweddariad i lawr — <label data-l10n-name="download-status"/>
+update-downloading-message = Yn llwytho i lawr y diweddariad — <label data-l10n-name="download-status"/>
+update-applying = Gosod y diweddariad…
+update-failed = Methodd y diweddaru. <label data-l10n-name="failed-link">Llwythwch y fersiwn diweddaraf i lawr</label>
+update-failed-main = Methodd y diweddaru. <a data-l10n-name="failed-link-main">Llwythwch y fersiwn diweddaraf i lawr</a>
+update-adminDisabled = Mae'r diweddariad wedi ei analluogi gan eich gweinyddwr
+update-noUpdatesFound = Mae { -brand-short-name } yn gyfredol
+update-otherInstanceHandlingUpdates = Mae { -brand-short-name } yn cael ei ddiweddaru gan enghraifft arall
+update-manual = Diweddariadau ar gael yn <label data-l10n-name="manual-link"/>
+update-unsupported = Nid oes modd i chi ddiweddaru'r system hon ymhellach. <label data-l10n-name="unsupported-link">Dysgu rhagor</label>
+update-restarting = Ailgychwyn…
+channel-description = Rydych ar sianel diweddaru <label data-l10n-name="current-channel"></label>.
+warningDesc-version = Mae { -brand-short-name } yn arbrofol a gall fod yn ansad.
+aboutdialog-help-user = Cymorth { -brand-product-name }
+aboutdialog-submit-feedback = Cyflwyno Adborth
+community-exp = <label data-l10n-name="community-exp-mozillaLink">Mae { -vendor-short-name }</label> yn <label data-l10n-name="community-exp-creditsLink">gymuned fyd-eang</label> sy'n cydweithio i gadw'r We yn agored, cyhoeddus ac ar gael i bawb.
+community-2 = Cynlluniwyd { -brand-short-name } gan <label data-l10n-name="community-mozillaLink">{ -vendor-short-name }</label>, <label data-l10n-name="community-creditsLink">cymuned fyd-eang</label> sy'n cydweithio i gadw'r We yn agored, cyhoeddus ac ar gael i bawb.
+helpus = Eisiau helpu? <label data-l10n-name="helpus-donateLink">Gallwch wneud rhodd</label> neu <label data-l10n-name="helpus-getInvolvedLink">ymuno â ni!</label>
+bottomLinks-license = Manylion Trwyddedu
+bottomLinks-rights = Hawliau'r Defnyddiwr
+bottomLinks-privacy = Polisi Preifatrwydd
+# Example of resulting string: 66.0.1 (64-bit)
+# Variables:
+#   $version (String): version of Firefox, e.g. 66.0.1
+#   $bits (Number): bits of the architecture (32 or 64)
+aboutDialog-version = { $version } ({ $bits }-did)
+# Example of resulting string: 66.0a1 (2019-01-16) (64-bit)
+# Variables:
+#   $version (String): version of Firefox for Nightly builds, e.g. 66.0a1
+#   $isodate (String): date in ISO format, e.g. 2019-01-16
+#   $bits (Number): bits of the architecture (32 or 64)
+aboutDialog-version-nightly = { $version } ({ $isodate }) ({ $bits }-did)
diff --git a/l10n-cy/browser/browser/aboutLogins.ftl b/l10n-cy/browser/browser/aboutLogins.ftl
new file mode 100644
index 0000000000..a28b64a7e0
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutLogins.ftl
@@ -0,0 +1,367 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# NOTE: New strings should use the about-logins- prefix.
+
+about-logins-page-title = Mewngofnodion a Chyfrineiriau
+
+# "Google Play" and "App Store" are both branding and should not be translated
+
+login-app-promo-title = Ewch â'ch cyfrineiriau i bob man
+login-app-promo-subtitle = Defnyddiwch yr ap { -lockwise-brand-name } - mae am ddim!
+login-app-promo-android =
+    .alt = Mae ar gael yn Google Play
+login-app-promo-apple =
+    .alt = Llwythwch i lawr o'r App Store
+login-filter =
+    .placeholder = Chwilio Mewngofnodion
+create-login-button = Creu Mewngofnod Newydd
+fxaccounts-sign-in-text = Defnyddiwch eich cyfrineiriau ar eich dyfeisiau eraill
+fxaccounts-sign-in-button = Mewngofnodi i { -sync-brand-short-name }
+fxaccounts-avatar-button =
+    .title = Rheoli cyfrif
+
+## The ⋯ menu that is in the top corner of the page
+
+menu =
+    .title = Agor dewislen
+# This menuitem is only visible on Windows and macOS
+about-logins-menu-menuitem-import-from-another-browser = Mewnforio o Borwr Arall…
+about-logins-menu-menuitem-import-from-a-file = Mewnforio o Ffeil…
+about-logins-menu-menuitem-export-logins = Allforio Mewngofnodion…
+about-logins-menu-menuitem-remove-all-logins = Tynnu Pob Mewngofnod…
+menu-menuitem-preferences =
+    { PLATFORM() ->
+        [windows] Opsiynau
+       *[other] Dewisiadau
+    }
+about-logins-menu-menuitem-help = Cymorth
+menu-menuitem-android-app = { -lockwise-brand-short-name } ar gyfer Android
+menu-menuitem-iphone-app = { -lockwise-brand-short-name } ar gyfer iPhone ac iPad
+
+## Login List
+
+login-list =
+    .aria-label = Mewngofnodi yn cyfateb i ymholiad chwilio
+login-list-count =
+    { $count ->
+        [zero] { $count } mewngofnod
+        [one] { $count } mewngofnod
+        [two] { $count } mewngofnod
+        [few] { $count } mewngofnod
+        [many] { $count } mewngofnod
+       *[other] { $count } mewngofnod
+    }
+login-list-sort-label-text = Trefnu yn ôl
+login-list-name-option = Enw (A-Z)
+login-list-name-reverse-option = Enw (Z-A)
+about-logins-login-list-alerts-option = Rhybuddion
+login-list-last-changed-option = Newidiwyd Diwethaf
+login-list-last-used-option = Defnyddiwyd Diwethaf
+login-list-intro-title = Heb ganfod mewngofnodion
+login-list-intro-description = Pan fyddwch yn cadw cyfrinair yn { -brand-product-name }, bydd yn ymddangos yma.
+about-logins-login-list-empty-search-title = Heb ganfod mewngofnodion
+about-logins-login-list-empty-search-description = Nid oes unrhyw ganlyniadau sy'n cyfateb i'ch chwiliad.
+login-list-item-title-new-login = Mewngofnod Newydd
+login-list-item-subtitle-new-login = Rhowch eich manylion mewngofnodi
+login-list-item-subtitle-missing-username = (dim enw defnyddwyr)
+about-logins-list-item-breach-icon =
+    .title = Gwefan wedi dioddef tor-data
+about-logins-list-item-vulnerable-password-icon =
+    .title = Cyfrinair bregus
+
+## Introduction screen
+
+login-intro-heading = Chwilio am eich mewngofnodi wedi'u cadw? Gosodwch { -sync-brand-short-name }.
+about-logins-login-intro-heading-logged-out = Chwilio am eich mewngofnodion wedi'u cadw? Gosodwch { -sync-brand-short-name } neu eu Mewnforio.
+about-logins-login-intro-heading-logged-in = Heb ganfod mewngofnodion wedi'u cydweddu.
+login-intro-description = Os gwnaethoch gadw eich mewngofnodion i { -brand-product-name } ar ddyfais wahanol, dyma sut i'w cael yma:
+login-intro-instruction-fxa = Creu neu fewngofnodi i'ch { -fxaccount-brand-name } ar y ddyfais lle mae'ch mewngofnodion yn cael eu cadw
+login-intro-instruction-fxa-settings = Sicrhewch eich bod wedi dewis y blwch gwirio Mewngofnodion yng Ngosodiadau { -sync-brand-short-name }
+about-logins-intro-instruction-help = Ewch i <a data-l10n-name="help-link"> Cefnogaeth { -lockwise-brand-short-name }</a> i gael rhagor o gymorth
+about-logins-intro-import = Os yw eich mewngofnodion yn cael eu cadw mewn porwr arall, gallwch <a data-l10n-name="import-link">eu mewnforio i { -lockwise-brand-short-name }</a>
+about-logins-intro-import2 = Os yw eich mewngofnodion wedi'u cadw y tu allan i { -brand-product-name }, gallwch <a data-l10n-name="import-browser-link">eu mewnforio o borwr arall</a> neu <a data-l10n-name="import-file-link">o ffeil</a>
+
+## Login
+
+login-item-new-login-title = Creu Mewngofnod Newydd
+login-item-edit-button = Golygu
+about-logins-login-item-remove-button = Tynnu
+login-item-origin-label = Cyfeiriad Gwefan
+login-item-tooltip-message = Gwnewch yn siŵr fod hyn yn cyfateb i union gyfeiriad y wefan lle rydych yn mewngofnodi.
+login-item-origin =
+    .placeholder = https://www.example.com
+login-item-username-label = Enw Defnyddiwr
+about-logins-login-item-username =
+    .placeholder = (dim enw defnyddwyr)
+login-item-copy-username-button-text = Copïo
+login-item-copied-username-button-text = Copïwyd
+login-item-password-label = Cyfrinair
+login-item-password-reveal-checkbox =
+    .aria-label = Dangos cyfrinair
+login-item-copy-password-button-text = Copïo
+login-item-copied-password-button-text = Copïwyd
+login-item-save-changes-button = Cadw Newidiadau
+login-item-save-new-button = Cadw
+login-item-cancel-button = Diddymu
+login-item-time-changed = Newidiwyd ddiwethaf: { DATETIME($timeChanged, day: "numeric", month: "long", year: "numeric") }
+login-item-time-created = Crëwyd: { DATETIME($timeCreated, day: "numeric", month: "long", year: "numeric") }
+login-item-time-used = Defnyddiwyd ddiwethaf: { DATETIME($timeUsed, day: "numeric", month: "long", year: "numeric") }
+
+## OS Authentication dialog
+
+about-logins-os-auth-dialog-caption = { -brand-full-name }
+
+## The macOS strings are preceded by the operating system with "Firefox is trying to "
+## and includes subtitle of "Enter password for the user "xxx" to allow this." These
+## notes are only valid for English. Please test in your respected locale.
+
+# This message can be seen when attempting to edit a login in about:logins on Windows.
+about-logins-edit-login-os-auth-dialog-message-win = I olygu eich mewngofnod, rhowch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen when attempting to edit a login in about:logins
+# On MacOS, only provide the reason that account verification is needed. Do not put a complete sentence here.
+about-logins-edit-login-os-auth-dialog-message-macosx = golygu'r mewngofnod sydd wedi'i gadw
+# This message can be seen when attempting to reveal a password in about:logins on Windows.
+about-logins-reveal-password-os-auth-dialog-message-win = I weld eich cyfrinair, rhowch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen when attempting to reveal a password in about:logins
+# On MacOS, only provide the reason that account verification is needed. Do not put a complete sentence here.
+about-logins-reveal-password-os-auth-dialog-message-macosx = dadlennu'r cyfrinair sydd wedi'i gadw
+# This message can be seen when attempting to copy a password in about:logins on Windows.
+about-logins-copy-password-os-auth-dialog-message-win = I gopïo'ch cyfrinair, rhowch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen when attempting to copy a password in about:logins
+# On MacOS, only provide the reason that account verification is needed. Do not put a complete sentence here.
+about-logins-copy-password-os-auth-dialog-message-macosx = copïo'r cyfrinair sydd wedi'i gadw
+
+## Master Password notification
+
+master-password-notification-message = Rhowch eich prif gyfrinair i weld mewngofnodi a chyfrineiriau wedi'u cadw
+# This message can be seen when attempting to export a password in about:logins on Windows.
+about-logins-export-password-os-auth-dialog-message-win = I allforio'ch mewngofnodion, nodwch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen when attempting to export a password in about:logins
+# On MacOS, only provide the reason that account verification is needed. Do not put a complete sentence here.
+about-logins-export-password-os-auth-dialog-message-macosx = allforio mewngofnodion a chyfrineiriau wedi'u cadw
+
+## Primary Password notification
+
+about-logins-primary-password-notification-message = Rhowch eich Prif Gyfrinair i weld mewngofnodi a chyfrineiriau wedi'u cadw
+master-password-reload-button =
+    .label = Mewngofnodi
+    .accesskey = M
+
+## Password Sync notification
+
+enable-password-sync-notification-message =
+    { PLATFORM() ->
+        [windows] Eisiau eich mewngofnodion ym mhobman rydych chi'n defnyddio { -brand-product-name }? Ewch i Opsiynau { -sync-brand-short-name } a dewiswch y blwch gwirio Mewngofnodi.
+       *[other] Eisiau eich mewngofnodion ym mhobman rydych chi'n defnyddio { -brand-product-name }? Ewch i Ddewisiadau { -sync-brand-short-name } a dewiswch y blwch gwirio Mewngofnodi.
+    }
+enable-password-sync-preferences-button =
+    .label =
+        { PLATFORM() ->
+            [windows] Ewch i { -sync-brand-short-name } Opsiynau
+           *[other] Ewch i { -sync-brand-short-name } Dewisiadau
+        }
+    .accesskey = E
+about-logins-enable-password-sync-dont-ask-again-button =
+    .label = Peidiwch gofyn i mi eto
+    .accesskey = g
+
+## Dialogs
+
+confirmation-dialog-cancel-button = Diddymu
+confirmation-dialog-dismiss-button =
+    .title = Diddymu
+about-logins-confirm-remove-dialog-title = Tynnu'r mewngofnod?
+confirm-delete-dialog-message = Nid oes modd dadwneud y weithred hon.
+about-logins-confirm-remove-dialog-confirm-button = Tynnu
+about-logins-confirm-remove-all-dialog-confirm-button-label =
+    { $count ->
+        [1] Tynnu
+        [zero] Tynnu
+        [one] Tynnu
+        [two] Tynnu
+        [few] Tynnu
+        [many] Tynnu
+       *[other] Tynnu'r Cyfan
+    }
+about-logins-confirm-remove-all-dialog-checkbox-label =
+    { $count ->
+        [1] Ie, tynnu'r mewngofnod
+        [zero] Ie, tynnu'r mewngofnodion
+        [one] Ie, tynnu'r mewngofnod
+        [two] Ie, tynnu'r mewngofnodion
+        [few] Ie, tynnu'r mewngofnodion
+        [many] Ie, tynnu'r mewngofnodion
+       *[other] Ie, tynnu'r mewngofnodion
+    }
+about-logins-confirm-remove-all-dialog-title =
+    { $count ->
+        [zero] Tynnu { $count } mewngofnodion
+        [one] Tynnu { $count } mewngofnod
+        [two] Tynnu { $count } fewngofnod
+        [few] Tynnu { $count } mewngofnod
+        [many] Tynnu { $count } mewngofnod
+       *[other] Tynnu { $count } mewngofnod
+    }
+about-logins-confirm-remove-all-dialog-message =
+    { $count ->
+        [1] Bydd hyn yn dileu'r mewngofnod rydych wedi'i gadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [zero] Bydd hyn yn dileu'r mewngofnodion rydych wedi'u cadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [one] Bydd hyn yn dileu'r mewngofnod rydych wedi'i gadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [two] Bydd hyn yn dileu'r mewngofnodion rydych wedi'u cadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [few] Bydd hyn yn dileu'r mewngofnodion rydych wedi'u cadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [many] Bydd hyn yn dileu'r mewngofnodion rydych wedi'u cadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+       *[other] Bydd hyn yn dileu'r mewngofnodion rydych wedi'u cadw i { -brand-short-name } ac unrhyw rybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+    }
+about-logins-confirm-remove-all-sync-dialog-title =
+    { $count ->
+        [zero] Tynnu'r { $count } mewngofnodion o'r holl ddyfeisiau?
+        [one] Tynnu'r { $count } mewngofnod o'r holl ddyfeisiau?
+        [two] Tynnu'r { $count } fewngofnod o'r holl ddyfeisiau?
+        [few] Tynnu'r { $count } mewngofnod o'r holl ddyfeisiau?
+        [many] Tynnu'r { $count } mewngofnod o'r holl ddyfeisiau?
+       *[other] Tynnu'r { $count } mewngofnod o'r holl ddyfeisiau?
+    }
+about-logins-confirm-remove-all-sync-dialog-message =
+    { $count ->
+        [1] Bydd hyn yn tynnu'r mewngofnod rydych wedi'i gadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [zero] Bydd hyn yn tynnu'r holl fewngofnodion rydych wedi'u cadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [one] Bydd hyn yn tynnu'r mewngofnod rydych wedi'i gadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [two] Bydd hyn yn tynnu'r holl fewngofnodion rydych wedi'u cadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [few] Bydd hyn yn tynnu'r holl fewngofnodion rydych wedi'u cadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+        [many] Bydd hyn yn tynnu'r holl fewngofnodion rydych wedi'u cadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+       *[other] Bydd hyn yn tynnu'r holl fewngofnodion rydych wedi'u cadw i { -brand-short-name } ar bob dyfais sy'n cael ei gydweddu i'ch { -fxaccount-brand-name }. Bydd hyn hefyd yn dileu rhybuddion tor-data sy'n ymddangos yma. Nid oes modd i chi ddadwneud y weithred hon.
+    }
+about-logins-confirm-export-dialog-title = Allforio mewngofnodion a chyfrineiriau
+about-logins-confirm-export-dialog-message = Bydd eich cyfrineiriau'n cael eu cadw fel testun darllenadwy (e.e. BadP@ssw0rd) fel y gall unrhyw un sy'n gallu agor y ffeil a allforiwyd eu gweld.
+about-logins-confirm-export-dialog-confirm-button = Allforio…
+about-logins-alert-import-title = Wedi Cwblhau Mewnforio
+about-logins-alert-import-message = Gweld crynodeb mewnforio manwl
+confirm-discard-changes-dialog-title = Hepgor newidiadau heb eu cadw?
+confirm-discard-changes-dialog-message = Bydd yr holl newidiadau sydd heb eu cadw'n cael eu colli.
+confirm-discard-changes-dialog-confirm-button = Dileu
+
+## Breach Alert notification
+
+about-logins-breach-alert-title = Tor-data Gwefan
+breach-alert-text = Cafodd cyfrineiriau eu ryddhau neu eu dwyn o'r wefan hon ers i chi ddiweddaru'ch manylion mewngofnodi ddiwethaf. Newid eich cyfrinair i ddiogelu eich cyfrif.
+about-logins-breach-alert-date = Digwyddodd y tor-data hwn ar { DATETIME($date, day: "numeric", month: "long", year: "numeric") }
+# Variables:
+#   $hostname (String) - The hostname of the website associated with the login, e.g. "example.com"
+about-logins-breach-alert-link = Mynd i { $hostname }
+about-logins-breach-alert-learn-more-link = Dysgu rhagor
+
+## Vulnerable Password notification
+
+about-logins-vulnerable-alert-title = Cyfrinair Bregus
+about-logins-vulnerable-alert-text2 = Defnyddiwyd y cyfrinair hwn ar gyfrif arall a oedd sy'n debygol o fod wedi bod mewn tor-data. Mae ailddefnyddio manylion yn peryglu'ch holl gyfrifon. Newid y cyfrinair hwn.
+# Variables:
+#   $hostname (String) - The hostname of the website associated with the login, e.g. "example.com"
+about-logins-vulnerable-alert-link = Mynd i { $hostname }
+about-logins-vulnerable-alert-learn-more-link = Dysgu rhagor
+
+## Error Messages
+
+# This is an error message that appears when a user attempts to save
+# a new login that is identical to an existing saved login.
+# Variables:
+#   $loginTitle (String) - The title of the website associated with the login.
+about-logins-error-message-duplicate-login-with-link = Mae cofnod ar gyfer { $loginTitle } gyda'r enw defnyddiwr hwnnw eisoes yn bodoli. <a data-l10n-name="duplicate-link"> Ewch i'r cofnod presennol? </a>
+# This is a generic error message.
+about-logins-error-message-default = Digwyddodd gwall wrth geisio gadw'r cyfrinair hwn.
+
+## Login Export Dialog
+
+# Title of the file picker dialog
+about-logins-export-file-picker-title = Allforio Ffeil Mewngofnodion
+# The default file name shown in the file picker when exporting saved logins.
+# This must end in .csv
+about-logins-export-file-picker-default-filename = mewngofnodion.csv
+about-logins-export-file-picker-export-button = Allforio
+# A description for the .csv file format that may be shown as the file type
+# filter by the operating system.
+about-logins-export-file-picker-csv-filter-title =
+    { PLATFORM() ->
+        [macos] Dogfen CSV
+       *[other] Ffeil CSV
+    }
+
+## Login Import Dialog
+
+# Title of the file picker dialog
+about-logins-import-file-picker-title = Allforio Ffeil Mewngofnodion
+about-logins-import-file-picker-import-button = Mewnforio
+# A description for the .csv file format that may be shown as the file type
+# filter by the operating system.
+about-logins-import-file-picker-csv-filter-title =
+    { PLATFORM() ->
+        [macos] Dogfen CSV
+       *[other] Ffeil CSV
+    }
+# A description for the .tsv file format that may be shown as the file type
+# filter by the operating system. TSV is short for 'tab separated values'.
+about-logins-import-file-picker-tsv-filter-title =
+    { PLATFORM() ->
+        [macos] Dogfen TSV
+       *[other] Ffeil TSV
+    }
+
+##
+## Variables:
+##  $count (number) - The number of affected elements
+
+about-logins-import-dialog-title = Wedi Cwblhau Mewnforio
+about-logins-import-dialog-items-added =
+    { $count ->
+        [zero] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+        [one] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+        [two] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+        [few] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+        [many] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+       *[other] <span>Ychwanegwyd mewngofnodion newydd:</span> <span data-l10n-name="count">{ $count }</span>
+    }
+about-logins-import-dialog-items-modified =
+    { $count ->
+        [zero] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+        [one] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+        [two] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+        [few] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+        [many] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+       *[other] <span>Diweddarwyd mewngofnodi presennol:</span> <span data-l10n-name="count">{ $count }</span>
+    }
+about-logins-import-dialog-items-no-change =
+    { $count ->
+        [zero] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [one] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [two] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [few] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [many] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+       *[other] <span>Mewngofnodion dyblyg wedi'u darganfod: </span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+    }
+about-logins-import-dialog-items-error =
+    { $count ->
+        [zero] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [one] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [two] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [few] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+        [many] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+       *[other] <span>Gwallau:</span> <span data-l10n-name="count">{ $count }</span><span data-l10n-name="meta">(heb ei fewnforio)</span>
+    }
+about-logins-import-dialog-done = Gorffen
+about-logins-import-dialog-error-title = Gwall Mewnforio
+about-logins-import-dialog-error-conflicting-values-title = Gwerthoedd Lluosog sy'n Gwrthdaro mewn Un Mewngofnod
+about-logins-import-dialog-error-conflicting-values-description = Er enghraifft: enwau defnyddwyr lluosog, cyfrineiriau, URLau, ac ati ar gyfer un mewngofnod.
+about-logins-import-dialog-error-file-format-title = Mater Fformat Ffeil
+about-logins-import-dialog-error-file-format-description = Penynnau colofnau anghywir neu coll. Gwnewch yn siŵr fod y ffeil yn cynnwys colofnau enw defnyddiwr, cyfrinair ac URL.
+about-logins-import-dialog-error-file-permission-title = Methu Darllen y Ffeil
+about-logins-import-dialog-error-file-permission-description = Nid oes gan { -brand-short-name } ganiatâd i ddarllen y ffeil. Ceisiwch newid caniatâd y ffeil.
+about-logins-import-dialog-error-unable-to-read-title = Methu Didoli'r Ffeil
+about-logins-import-dialog-error-unable-to-read-description = Gwnewch yn siŵr eich bod wedi dewis ffeil CSV neu TSV.
+about-logins-import-dialog-error-no-logins-imported = Heb fewnforio unrhyw fewngofnodion
+about-logins-import-dialog-error-learn-more = Dysgu rhagor
+about-logins-import-dialog-error-try-again = Ceisiwch eto…
+about-logins-import-dialog-error-cancel = Diddymu
+
+## Logins import report page
+
+about-logins-import-report-page-title = Mewnforio Adroddiad Cryno
diff --git a/l10n-cy/browser/browser/aboutPolicies.ftl b/l10n-cy/browser/browser/aboutPolicies.ftl
new file mode 100644
index 0000000000..f09e180c9f
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutPolicies.ftl
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-policies-title = Polisïau Mentrau
+
+# 'Active' is used to describe the policies that are currently active
+active-policies-tab = Gweithredol
+errors-tab = Gwallau
+documentation-tab = Dogfennaeth
+
+no-specified-policies-message = Mae'r gwasanaeth Polisïau Menter yn weithredol ond nid oes unrhyw bolisïau wedi'u galluogi.
+inactive-message = Mae'r gwasanaeth Polisïau Menter yn anweithredol.
+
+policy-name = Enw Polisi
+policy-value = Gwerth Polisi
+policy-errors = Gwallau Polisi
diff --git a/l10n-cy/browser/browser/aboutPrivateBrowsing.ftl b/l10n-cy/browser/browser/aboutPrivateBrowsing.ftl
new file mode 100644
index 0000000000..bb3c17fdb7
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutPrivateBrowsing.ftl
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+privatebrowsingpage-open-private-window-label = Agor Ffenestr Breifat
+    .accesskey = F
+about-private-browsing-search-placeholder = Chwilio'r We
+about-private-browsing-info-title = Rydych mewn Ffenestr Breifat
+about-private-browsing-info-myths = Mythau cyffredin am bori preifat
+about-private-browsing =
+    .title = Chwilio'r We
+about-private-browsing-not-private = Nid ydych mewn ffenestr breifat ar hyn o bryd.
+about-private-browsing-info-description = Mae { -brand-short-name } yn clirio eich hanes chwilio a phori pan fyddwch yn cau'r ap neu'n cau pob tab a ffenestr Pori Preifat. Er nad yw hyn yn eich gwneud yn ddienw i wefannau neu i'ch darparwr gwasanaeth rhyngrwyd, mae'n ei gwneud yn haws i chi gadw'r hyn rydych chi'n ei wneud ar-lein yn breifat rhag unrhyw un arall sy'n defnyddio'r cyfrifiadur hwn.
+about-private-browsing-need-more-privacy = Angen mwy o breifatrwydd?
+about-private-browsing-turn-on-vpn = Rhowch gynnig ar { -mozilla-vpn-brand-name }
+# This string is the title for the banner for search engine selection
+# in a private window.
+# Variables:
+#   $engineName (String) - The engine name that will currently be used for the private window.
+about-private-browsing-search-banner-title = { $engineName } yw eich peiriant chwilio rhagosodedig mewn Ffenestri Preifat
+about-private-browsing-search-banner-description =
+    { PLATFORM() ->
+        [windows] I ddewis peiriant chwilio gwahanol ewch i <a data-l10n-name="link-options">Opsiynau</a>
+       *[other] I ddewis peiriant chwilio gwahanol ewch i <a data-l10n-name="link-options">Dewisiadau</a>
+    }
+about-private-browsing-search-banner-close-button =
+    .aria-label = Cau
diff --git a/l10n-cy/browser/browser/aboutRestartRequired.ftl b/l10n-cy/browser/browser/aboutRestartRequired.ftl
new file mode 100644
index 0000000000..45781f6753
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutRestartRequired.ftl
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+restart-required-title = Mae Angen Ail Gychwyn
+restart-required-header = Ymddiheuriadau. Mae angen gwneud un peth bach er mwyn cadw i fynd.
+restart-required-intro-brand = Mae { -brand-short-name } newydd gael ei ddiweddaru yn y cefndir. Cliciwch Ailgychwyn { -brand-short-name } i gwblhau'r diweddariad.
+restart-required-description = Byddwn yn adfer eich holl dudalennau, ffenestri a thabiau wedyn , fel bod modd i chi fod ar eich ffordd yn sydyn.
+
+restart-button-label = Ailgychwyn { -brand-short-name }
diff --git a/l10n-cy/browser/browser/aboutRobots.ftl b/l10n-cy/browser/browser/aboutRobots.ftl
new file mode 100644
index 0000000000..e8fc0e2c7f
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutRobots.ftl
@@ -0,0 +1,29 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used in the about:robots page, which ties in with the
+### robots theme used in the Firefox 3 Beta 2/3 first run pages.
+### They're just meant to be fun and whimsical, with references to some geeky
+### but well-known robots in movies and books. Be creative with translations!
+
+# Nonsense line from the movie "The Day The Earth Stood Still". No translation needed.
+page-title = Gort! Klaatu barada nikto!
+# Movie: Logan's Run... Box (cyborg): "Welcome Humans! I am ready for you."
+error-title-text = Croeso Ddynionach!
+# Movie: The Day The Earth Stood Still. Spoken by Klaatu.
+error-short-desc-text = Rydym wedi dod i'ch cyfarfod mewn heddwch ac ewyllys da!
+# Various books by Isaac Asimov. http://en.wikipedia.org/wiki/Three_Laws_of_Robotics
+error-long-desc1 = Nid yw robotiaid yn cael anafu dynion neu drwy ddiffyg gweithredu gadel iddynt gael eu niweidio.
+# Movie: Blade Runner. Batty: "I've seen things you people wouldn’t believe..."
+error-long-desc2 = Mae robotiaid wedi gweld pethau fyddwch chi ddim yn ei gredu.
+# Book: Hitchhiker’s Guide To The Galaxy. What the Sirius Cybernetics Corporation calls robots.
+error-long-desc3 = Robot yw dy Ffrind Plastig sy'n Hwyl a Sbort.
+# TV: Futurama. Bender's first line is "Bite my shiny metal ass."
+error-long-desc4 = Mae gan robotiaid rhan ôl metel disglair na ddylid ei gnoi.
+# TV: Battlestar Galactica (2004 series). From the opening text.
+error-trailer-desc-text = Ac mae ganddyn nhw gynllun.
+# Book: Hitchhiker's Guide To The Galaxy. Arthur presses a button and it warns him.
+error-try-again = Ceisiwch eto
+    .label2 = Paid pwyso'r botwm yma eto.
diff --git a/l10n-cy/browser/browser/aboutSessionRestore.ftl b/l10n-cy/browser/browser/aboutSessionRestore.ftl
new file mode 100644
index 0000000000..07e7315f99
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutSessionRestore.ftl
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+restore-page-tab-title = Adfer y Sesiwn
+
+# The title is intended to be apologetic and disarming, expressing dismay
+# and regret that we are unable to restore the session for the user
+restore-page-error-title = Ymddiheuriadau. Rydym yn cael anhawster adfer eich tudalennau.
+restore-page-problem-desc = Rydym yn cael anhawster adfer eich sesiwn pori diwethaf. Dewiswch Adfer Sesiwn er mwyn ceisio eto.
+restore-page-try-this = Dal dim yn gallu adfer eich sesiwn? Weithiau bydd tab yn achosi problem. Edrychwch ar dabiau blaenorol, tynnwch y marc ticio o'r tabiau does dim angen eu hadfer ac yna adfer.
+
+restore-page-hide-tabs = Cuddio'r Tabiau Blaenorol
+restore-page-show-tabs = Edrych ar Dabiau Blaenorol
+
+# When tabs are distributed across multiple windows, this message is used as a
+# header above the group of tabs for each window.
+#
+# Variables:
+#    $windowNumber: Progressive number associated to each window
+restore-page-window-label = Ffenestr { $windowNumber }
+
+restore-page-restore-header =
+    .label = Adfer
+
+restore-page-list-header =
+    .label = Ffenestri a Thabiau
+
+restore-page-try-again-button =
+    .label = Adfer y Sesiwn
+    .accesskey = A
+
+restore-page-close-button =
+    .label = Cychwyn Sesiwn Newydd
+    .accesskey = N
+
+## The following strings are used in about:welcomeback
+
+welcome-back-tab-title = Llwyddiant!
+welcome-back-page-title = Llwyddiant!
+welcome-back-page-info = Mae { -brand-short-name } yn barod i fynd.
+
+welcome-back-restore-button =
+    .label = Ffwrdd â ni!
+    .accesskey = F
+
+welcome-back-restore-all-label = Adfer pob ffenestr a thab
+welcome-back-restore-some-label = Adfer dim ond y rhai rydych eu heisiau
+
+welcome-back-page-info-link = Mae eich ychwanegion a'ch cyfaddasu wedi eu tynnu ac mae gosodiadau eich porwr wedi eu hadfer i'w rhagosodiad. Os nad yw hyn wedi trwsio eich anhawster, <a data-l10n-name="link-more">dysgu rhagor am beth fedrwch ei wneud.</a>
+
diff --git a/l10n-cy/browser/browser/aboutTabCrashed.ftl b/l10n-cy/browser/browser/aboutTabCrashed.ftl
new file mode 100644
index 0000000000..7f833250e6
--- /dev/null
+++ b/l10n-cy/browser/browser/aboutTabCrashed.ftl
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+crashed-title = Adroddwr chwalu tab
+crashed-close-tab-button = Cau Tab
+crashed-restore-tab-button = Adfer y Tab Hwn
+crashed-restore-all-button = Adfer Pob Tab Chwalwyd
+crashed-header = Ach. Mae eich tab newydd chwalu.
+crashed-offer-help = Gallwn ni helpu!
+crashed-single-offer-help-message = Dewiswch { crashed-restore-tab-button } i ail lwytho'r dudalen.
+crashed-multiple-offer-help-message = Dewiswch { crashed-restore-tab-button } neu { crashed-restore-all-button } i ail lwytho'r dudalen/tudalennau.
+crashed-request-help = A wnewch chi ein helpu ni?
+crashed-request-help-message = Mae adroddiadau chwalu yn caniatáu i ni ddadansoddi anawsterau a gwneud { -brand-short-name } yn well.
+crashed-request-report-title = Adrodd am y tab
+crashed-send-report = Anfonwch adroddiad chwalu awtomataidd fel bod modd i ni drwsio materion fel hyn.
+crashed-send-report-2 = Anfonwch adroddiad chwalu awtomataidd fel bod modd i ni drwsio materion fel hyn.
+crashed-comment =
+    .placeholder = Sylwadau dewisol (sylwadau yn weladwy'n gyhoeddus)
+crashed-include-URL = Cofiwch gynnwys URLau gwefannau roeddech arnynt pan chwalodd { -brand-short-name }.
+crashed-include-URL-2 = Cofiwch gynnwys URLau gwefannau roeddech arnynt pan chwalodd { -brand-short-name }.
+crashed-email-placeholder = Rhowch eich cyfeiriad e-bost yma
+crashed-email-me = Hysbysu pan fydd rhagor o wybodaeth ar gael
+crashed-report-sent = Mae'r adroddiad chwalu wedi ei gyflwyno: diolch am gynorthwyo i wneud { -brand-short-name } yn well!
+crashed-request-auto-submit-title = Gofyn am dabiau cefndir
+crashed-auto-submit-checkbox = Diweddarwch y dewisiadau i gyflwyno adroddiadau'n awtomatig pan fydd { -brand-short-name } yn chwalu.
+crashed-auto-submit-checkbox-2 = Diweddarwch y dewisiadau i gyflwyno adroddiadau'n awtomatig pan fydd { -brand-short-name } yn chwalu.
diff --git a/l10n-cy/browser/browser/allTabsMenu.ftl b/l10n-cy/browser/browser/allTabsMenu.ftl
new file mode 100644
index 0000000000..cdf4fc2f62
--- /dev/null
+++ b/l10n-cy/browser/browser/allTabsMenu.ftl
@@ -0,0 +1,29 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+all-tabs-menu-undo-close-tabs =
+    .label =
+        { $tabCount ->
+            [1] Dadwneud Cau Tab
+            [zero] Dadwneud Cau Tabiau
+            [one] Dadwneud Cau Tab
+            [two] Dadwneud Cau Tabiau
+            [few] Dadwneud Cau Tabiau
+            [many] Dadwneud Cau Tabiau
+           *[other] Dadwneud Cau Tabiau
+        }
+
+# "Search" is a verb, as in "Search through tabs".
+all-tabs-menu-search-tabs =
+    .label = Chwilio'r Tabiau
+
+all-tabs-menu-new-user-context =
+    .label = Tab Cynhwysydd Newydd
+
+all-tabs-menu-hidden-tabs =
+    .label = Tabiau Cudd
+
+all-tabs-menu-manage-user-context =
+    .label = Rheoli Cynhwysyddion
+    .accesskey = R
diff --git a/l10n-cy/browser/browser/appMenuNotifications.ftl b/l10n-cy/browser/browser/appMenuNotifications.ftl
new file mode 100644
index 0000000000..f2c8cff012
--- /dev/null
+++ b/l10n-cy/browser/browser/appMenuNotifications.ftl
@@ -0,0 +1,78 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+appmenu-update-available =
+    .label = Mae diweddariad newydd o { -brand-shorter-name } ar gael.
+    .buttonlabel = Llwytho'r Diweddariad i Lawr
+    .buttonaccesskey = L
+    .secondarybuttonlabel = Nid Nawr
+    .secondarybuttonaccesskey = N
+appmenu-update-available-message = Diweddarwch { -brand-shorter-name } ar gyfer y diweddaraf mewn cyflymder a phreifatrwydd.
+appmenu-update-manual =
+    .label = Nid yw { -brand-shorter-name } yn gallu diweddaru i'r fersiwn diweddaraf.
+    .buttonlabel = Llwytho { -brand-shorter-name } i lawr.
+    .buttonaccesskey = L
+    .secondarybuttonlabel = Nid Nawr
+    .secondarybuttonaccesskey = N
+appmenu-update-manual-message = Llwythwch gopi newydd o { -brand-shorter-name } i lawr ac mi wnawn ni eich helpu i'w gosod.
+appmenu-update-whats-new =
+    .value = Gweld beth sy'n newydd.
+appmenu-update-unsupported =
+    .label = Nid yw { -brand-shorter-name } yn gallu diweddaru i'r fersiwn diweddaraf.
+    .buttonlabel = Dysgu rhagor
+    .buttonaccesskey = D
+    .secondarybuttonlabel = Cau
+    .secondarybuttonaccesskey = C
+appmenu-update-unsupported-message = Nid yw'r fersiwn diweddaraf o { -brand-shorter-name } yn cael ei gefnogi ar eich system.
+appmenu-update-restart =
+    .label = Ailgychwyn i ddiweddaru { -brand-shorter-name }
+    .buttonlabel = Ail gychwyn ac Adfer
+    .buttonaccesskey = A
+    .secondarybuttonlabel = Nid Nawr
+    .secondarybuttonaccesskey = N
+appmenu-update-restart-message = Ar ôl ailgychwyn cyflym, bydd { -brand-shorter-name } yn adfer eich tabiau a ffenestri agored sydd ddim yn y modd Pori Preifat.
+appmenu-update-other-instance =
+    .label = Nid yw { -brand-shorter-name } yn gallu diweddaru i'r fersiwn diweddaraf.
+    .buttonlabel = Diweddaru { -brand-shorter-name } beth bynnag
+    .buttonaccesskey = D
+    .secondarybuttonlabel = Nid Nawr
+    .secondarybuttonaccesskey = N
+appmenu-update-other-instance-message = Mae diweddariad newydd { -brand-shorter-name } ar gael, ond nid oes modd ei osod oherwydd bod copi arall o { -brand-shorter-name } yn rhedeg. Caewch ef i barhau â'r diweddariad, neu dewiswch ei ddiweddaru beth bynnag (efallai na fydd y copi arall yn gweithio'n iawn nes i chi ei ailgychwyn).
+appmenu-addon-private-browsing-installed =
+    .buttonlabel = Iawn, rwy'n deall
+    .buttonaccesskey = I
+appmenu-addon-post-install-message = Rheolwch eich ychwanegion drwy glicio <image data-l10n-name='addon-install-icon'></image> yn newislen <image data-l10n-name='addon-menu-icon'></image>.
+appmenu-addon-post-install-incognito-checkbox =
+    .label = Caniatáu i'r estyniad yma redeg mewn Ffenestri Preifat
+    .accesskey = C
+appmenu-new-tab-controlled =
+    .label = Mae eich Tab Newydd wedi newid.
+    .buttonlabel = Cadw Newidiadau
+    .buttonaccesskey = N
+    .secondarybuttonlabel = Analluogi Estyniad
+    .secondarybuttonaccesskey = A
+appmenu-homepage-controlled =
+    .label = Mae eich tudalen cartref wedi newid.
+    .buttonlabel = Cadw'r Newidiadau
+    .buttonaccesskey = C
+    .secondarybuttonlabel = Analluogi'r Estyniad
+    .secondarybuttonaccesskey = A
+appmenu-new-tab-controlled-changes =
+    .label = Mae eich tab newydd wedi newid.
+    .buttonlabel = Cadw'r Newidiadau
+    .buttonaccesskey = N
+    .secondarybuttonlabel = Rheoli Tabiau Newydd
+    .secondarybuttonaccesskey = R
+appmenu-homepage-controlled-changes =
+    .label = Mae eich tudalen cartref wedi newid.
+    .buttonlabel = Cadw'r Newidiadau
+    .buttonaccesskey = N
+    .secondarybuttonlabel = Rheoli'r Dudalen Cartref
+    .secondarybuttonaccesskey = T
+appmenu-tab-hide-controlled =
+    .label = Mynd i’ch Tabiau Cudd
+    .buttonlabel = Cadw Tabiau’n Gudd
+    .buttonaccesskey = C
+    .secondarybuttonlabel = Analluogi’r Estyniad
+    .secondarybuttonaccesskey = A
diff --git a/l10n-cy/browser/browser/appmenu.ftl b/l10n-cy/browser/browser/appmenu.ftl
new file mode 100644
index 0000000000..8945375eaf
--- /dev/null
+++ b/l10n-cy/browser/browser/appmenu.ftl
@@ -0,0 +1,155 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## App Menu
+
+appmenuitem-update-banner =
+    .label-update-downloading = Llwytho diweddariad { -brand-shorter-name } i lawr
+appmenuitem-protection-dashboard-title = Bwrdd Gwaith Diogelwch
+appmenuitem-customize-mode =
+    .label = Cyfaddasu…
+
+## Zoom Controls
+
+appmenuitem-new-window =
+    .label = Ffenestr Newydd
+appmenuitem-new-private-window =
+    .label = Ffenestr Breifat Newydd
+appmenuitem-passwords =
+    .label = Cyfrineiriau
+appmenuitem-extensions-and-themes =
+    .label = Estyniadau a Themâu
+appmenuitem-find-in-page =
+    .label = Canfod ar Dudalen…
+appmenuitem-more-tools =
+    .label = Rhagor o Offer
+appmenuitem-exit =
+    .label = Gadael
+# Settings is now used to access the browser settings across all platforms,
+# instead of Options or Preferences.
+appmenuitem-settings =
+    .label = Gosodiadau
+
+## Zoom and Fullscreen Controls
+
+appmenuitem-zoom-enlarge =
+    .label = Chwyddo mewn
+appmenuitem-zoom-reduce =
+    .label = Chwyddo allan
+appmenuitem-fullscreen =
+    .label = Sgrin Lawn
+
+## Firefox Account toolbar button and Sync panel in App menu.
+
+fxa-toolbar-sync-now =
+    .label = Cydweddu Nawr
+appmenuitem-save-page =
+    .label = Cadw Tudalen Fel…
+
+## What's New panel in App menu.
+
+whatsnew-panel-header = Beth sy'n Newydd
+# Checkbox displayed at the bottom of the What's New panel, allowing users to
+# enable/disable What's New notifications.
+whatsnew-panel-footer-checkbox =
+    .label = Hysbysu am nodweddion newydd
+    .accesskey = H
+
+## The Firefox Profiler – The popup is the UI to turn on the profiler, and record
+## performance profiles. To enable it go to profiler.firefox.com and click
+## "Enable Profiler Menu Button".
+
+profiler-popup-title =
+    .value = { -profiler-brand-name }
+profiler-popup-reveal-description-button =
+    .aria-label = Dangos rhagor o wybodaeth
+profiler-popup-description-title =
+    .value = Cofnodi, dadansoddi, rhannu
+profiler-popup-description = Cydweithiwch ar faterion perfformiad trwy gyhoeddi proffiliau i'w rhannu â'ch tîm.
+profiler-popup-learn-more = Dysgu rhagor
+profiler-popup-settings =
+    .value = Gosod­iadau
+# This link takes the user to about:profiling, and is only visible with the Custom preset.
+profiler-popup-edit-settings = Golygu Gosodiadau...
+profiler-popup-disabled =
+    Mae'r proffiliwr wedi'i analluogi ar hyn o bryd, yn fwyaf tebygol oherwydd fod ffenestr Pori Preifat
+    ar agor
+profiler-popup-recording-screen = Yn cofnodi…
+# The profiler presets list is generated elsewhere, but the custom preset is defined
+# here only.
+profiler-popup-presets-custom =
+    .label = Cyfaddas
+profiler-popup-start-recording-button =
+    .label = Cychwyn Cofnodi
+profiler-popup-discard-button =
+    .label = Dileu
+profiler-popup-capture-button =
+    .label = Cipio
+profiler-popup-start-shortcut =
+    { PLATFORM() ->
+        [macos] ⌃⇧1
+       *[other] Ctrl+Shift+1
+    }
+profiler-popup-capture-shortcut =
+    { PLATFORM() ->
+        [macos] ⌃⇧2
+       *[other] Ctrl+Shift+2
+    }
+
+## Help panel
+
+appmenu-help-header =
+    .title = Cymorth { -brand-shorter-name }
+appmenu-about =
+    .label = Ynghylch { -brand-shorter-name }
+    .accesskey = n
+appmenu-help-product =
+    .label = Cymorth { -brand-shorter-name }
+    .accesskey = m
+appmenu-help-show-tour =
+    .label = Cyflwyno { -brand-shorter-name }
+    .accesskey = C
+appmenu-help-import-from-another-browser =
+    .label = Mewnforio o Borwr arall ...
+    .accesskey = M
+appmenu-help-keyboard-shortcuts =
+    .label = Llwybrau Byr Bysellfwrdd
+    .accesskey = B
+appmenu-get-help =
+    .label = Derbyn Cymorth
+    .accesskey = D
+appmenu-help-troubleshooting-info =
+    .label = Gwybodaeth am Ddatrys Problemau
+    .accesskey = G
+appmenu-help-taskmanager =
+    .label = Rheolwr Tasgau
+appmenu-help-feedback-page =
+    .label = Cyflwyno Adborth…
+    .accesskey = A
+
+## appmenu-help-safe-mode-without-addons and appmenu-help-safe-mode-without-addons
+## are mutually exclusive, so it's possible to use the same accesskey for both.
+
+appmenu-help-safe-mode-without-addons =
+    .label = Ailgychwyn gydag Ychwanegion wedi eu Hanalluogi…
+    .accesskey = A
+appmenu-help-safe-mode-with-addons =
+    .label = Ailgychwyn gydag Ychwanegion wedi eu Hanalluogi
+    .accesskey = A
+
+## appmenu-help-report-deceptive-site and appmenu-help-not-deceptive
+## are mutually exclusive, so it's possible to use the same accesskey for both.
+
+appmenu-help-report-deceptive-site =
+    .label = Adroddwch ar wefan twyllodrus…
+    .accesskey = t
+appmenu-help-not-deceptive =
+    .label = Nid yw hon yn wefan twyllodrus…
+    .accesskey = t
+
+##
+
+appmenu-help-check-for-update =
+    .label = Gwirio am Ddiweddariadau…
diff --git a/l10n-cy/browser/browser/branding/brandings.ftl b/l10n-cy/browser/browser/branding/brandings.ftl
new file mode 100644
index 0000000000..8ed0b6e58d
--- /dev/null
+++ b/l10n-cy/browser/browser/branding/brandings.ftl
@@ -0,0 +1,32 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## The following feature names must be treated as a brand, and kept in English.
+## They cannot be:
+## - Declined to adapt to grammatical case.
+## - Transliterated.
+## - Translated.
+
+## The following feature names must be treated as a brand.
+##
+## They cannot be:
+## - Transliterated.
+## - Translated.
+##
+## Declension should be avoided where possible, leaving the original
+## brand unaltered in prominent UI positions.
+##
+## For further details, consult:
+## https://mozilla-l10n.github.io/styleguides/mozilla_general/#brands-copyright-and-trademark
+
+-facebook-container-brand-name = Facebook Container
+-lockwise-brand-name = Firefox Lockwise
+-lockwise-brand-short-name = Lockwise
+-monitor-brand-name = Firefox Monitor
+-monitor-brand-short-name = Monitor
+-pocket-brand-name = Pocket
+-send-brand-name = Firefox Send
+-screenshots-brand-name = Firefox Screenshots
+-mozilla-vpn-brand-name = Mozilla VPN
+-profiler-brand-name = Firefox Profiler
diff --git a/l10n-cy/browser/browser/branding/sync-brand.ftl b/l10n-cy/browser/browser/branding/sync-brand.ftl
new file mode 100644
index 0000000000..80012d5461
--- /dev/null
+++ b/l10n-cy/browser/browser/branding/sync-brand.ftl
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+-sync-brand-short-name = Sync
+
+# “Sync” can be localized, “Firefox” must be treated as a brand,
+# and kept in English.
+-sync-brand-name = Firefox Sync
+
+# “Account” can be localized, “Firefox” must be treated as a brand,
+# and kept in English.
+-fxaccount-brand-name = Cyfrif Firefox
diff --git a/l10n-cy/browser/browser/browser.ftl b/l10n-cy/browser/browser/browser.ftl
new file mode 100644
index 0000000000..380a9af6d8
--- /dev/null
+++ b/l10n-cy/browser/browser/browser.ftl
@@ -0,0 +1,618 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## The main browser window's title
+
+# These are the default window titles everywhere except macOS. The first two
+# attributes are used when the web content opened has no title:
+#
+# default - "Mozilla Firefox"
+# private - "Mozilla Firefox (Private Browsing)"
+#
+# The last two are for use when there *is* a content title.
+# Variables:
+#  $content-title (String): the title of the web content.
+browser-main-window =
+    .data-title-default = { -brand-full-name }
+    .data-title-private = { -brand-full-name } (Pori Preifat)
+    .data-content-title-default = { $content-title } - { -brand-full-name }
+    .data-content-title-private = { $content-title } - { -brand-full-name } (Pori Preifat)
+# These are the default window titles on macOS. The first two are for use when
+# there is no content title:
+#
+# "default" - "Mozilla Firefox"
+# "private" - "Mozilla Firefox — (Private Browsing)"
+#
+# The last two are for use when there *is* a content title.
+# Do not use the brand name in the last two attributes, as we do on non-macOS.
+#
+# Also note the other subtle difference here: we use a `-` to separate the
+# brand name from `(Private Browsing)`, which does not happen on other OSes.
+#
+# Variables:
+#  $content-title (String): the title of the web content.
+browser-main-window-mac =
+    .data-title-default = { -brand-full-name }
+    .data-title-private = { -brand-full-name } - (Pori Preifat)
+    .data-content-title-default = { $content-title }
+    .data-content-title-private = { $content-title } - (Pori Preifat)
+# This gets set as the initial title, and is overridden as soon as we start
+# updating the titlebar based on loaded tabs or private browsing state.
+# This should match the `data-title-default` attribute in both
+# `browser-main-window` and `browser-main-window-mac`.
+browser-main-window-title = { -brand-full-name }
+
+##
+
+urlbar-identity-button =
+    .aria-label = Gweld manylion y wefan
+
+## Tooltips for images appearing in the address bar
+
+urlbar-services-notification-anchor =
+    .tooltiptext = Agor panel y neges gosod
+urlbar-web-notification-anchor =
+    .tooltiptext = Newid p'un ai rydych yn derbyn hysbysiadau o'r wefan
+urlbar-midi-notification-anchor =
+    .tooltiptext = Agor panel MIDI
+urlbar-eme-notification-anchor =
+    .tooltiptext = Rheoli'r defnydd o feddalwedd DRM
+urlbar-web-authn-anchor =
+    .tooltiptext = Agor panel Dilysu Gwe
+urlbar-canvas-notification-anchor =
+    .tooltiptext = Rheoli caniatâd tynnu canfas
+urlbar-web-rtc-share-microphone-notification-anchor =
+    .tooltiptext = Rheoli rhannu eich meicroffon gyda'r wefan
+urlbar-default-notification-anchor =
+    .tooltiptext = Agor y panel negesu
+urlbar-geolocation-notification-anchor =
+    .tooltiptext = Agor panel cais y lleoliad
+urlbar-xr-notification-anchor =
+    .tooltiptext = Agor panel caniatâd rhithrealaeth
+urlbar-storage-access-anchor =
+    .tooltiptext = Agor panel caniatâd gweithgaredd pori
+urlbar-translate-notification-anchor =
+    .tooltiptext = Cyfieithu'r dudalen hon
+urlbar-web-rtc-share-screen-notification-anchor =
+    .tooltiptext = Rheoli rhannu eich ffenestri neu sgrin gyda'r wefan
+urlbar-indexed-db-notification-anchor =
+    .tooltiptext = Agor y panel neges storio all-lein
+urlbar-password-notification-anchor =
+    .tooltiptext = Agor panel neges y cyfrinair cadw
+urlbar-translated-notification-anchor =
+    .tooltiptext = Rheoli cyfieithu tudalennau
+urlbar-plugins-notification-anchor =
+    .tooltiptext = Rheoli defnydd ategion
+urlbar-web-rtc-share-devices-notification-anchor =
+    .tooltiptext = Rheoli rhannu eich camera a/neu feicroffon gyda'r wefan
+urlbar-autoplay-notification-anchor =
+    .tooltiptext = Agor panel awtochwarae
+urlbar-persistent-storage-notification-anchor =
+    .tooltiptext = Cadw data mewn Storfa Barhaus
+urlbar-addons-notification-anchor =
+    .tooltiptext = Agor panel neges gosod yr ychwanegyn
+urlbar-tip-help-icon =
+    .title = Derbyn cymorth
+urlbar-search-tips-confirm = Iawn, rwy'n deall
+# Read out before Urlbar Tip text content so screenreader users know the
+# subsequent text is a tip offered by the browser. It should end in a colon or
+# localized equivalent.
+urlbar-tip-icon-description =
+    .alt = Awgrym:
+
+## Prompts users to use the Urlbar when they open a new tab or visit the
+## homepage of their default search engine.
+## Variables:
+##  $engineName (String): The name of the user's default search engine. e.g. "Google" or "DuckDuckGo".
+
+urlbar-search-tips-onboard = Teipio llai, canfod mwy: Chwiliwch gyda { $engineName } yn syth o'ch bar cyfeiriad.
+urlbar-search-tips-redirect-2 = Cychwynnwch eich chwilio yma i weld awgrymiadau gan { $engineName } a'ch hanes pori.
+# Prompts users to use the Urlbar when they are typing in the domain of a
+# search engine, e.g. google.com or amazon.com.
+urlbar-tabtosearch-onboard = Dewiswch y llwybr byr hwn i ddod o hyd i'r hyn sydd ei angen arnoch yn gynt.
+
+## Local search mode indicator labels in the urlbar
+
+urlbar-search-mode-bookmarks = Nodau tudalen
+urlbar-search-mode-tabs = Tabiau
+urlbar-search-mode-history = Hanes
+
+##
+
+urlbar-geolocation-blocked =
+    .tooltiptext = Rydych wedi rhwystro'r manylion lleoliad ar gyfer y wefan hon.
+urlbar-xr-blocked =
+    .tooltiptext = Rydych wedi rhwystro mynediad dyfais rhithrealaeth ar gyfer y wefan hon.
+urlbar-web-notifications-blocked =
+    .tooltiptext = Rydych wedi rhwystro hysbysiadau ar gyfer y wefan hon.
+urlbar-camera-blocked =
+    .tooltiptext = Rydych wedi diffodd eich camera ar gyfer y wefan hon.
+urlbar-microphone-blocked =
+    .tooltiptext = Rydych wedi diffodd eich meicroffon ar gyfer y wefan hon.
+urlbar-screen-blocked =
+    .tooltiptext = Rydych wedi rhwystro'r wefan rhag rhannu eich sgrin.
+urlbar-persistent-storage-blocked =
+    .tooltiptext = Rydych wedi rhwystro storio data parhaus ar gyfer y wefan hon.
+urlbar-popup-blocked =
+    .tooltiptext = Rydych wedi rhwystro llamlenni ar gyfer y wefan hon.
+urlbar-autoplay-media-blocked =
+    .tooltiptext = Rydych wedi rhwystro cyfrwng awtochwarae gyda seiniau ar gyfer y wefan hon.
+urlbar-canvas-blocked =
+    .tooltiptext = Rydych wedi rhwystro tynnu data canvas o'r wefan hon.
+urlbar-midi-blocked =
+    .tooltiptext = Rydych wedi rhwystro mynediad MIDI ar gyfer y wefan hon.
+urlbar-install-blocked =
+    .tooltiptext = Rydych wedi rhwystro gosod ychwanegion ar gyfer y wefan hon.
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the edit bookmark command.
+urlbar-star-edit-bookmark =
+    .tooltiptext = Golygu'r nod tudalen ({ $shortcut })
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the add bookmark command.
+urlbar-star-add-bookmark =
+    .tooltiptext = Gosod nod tudalen i'r dudalen ({ $shortcut })
+
+## Page Action Context Menu
+
+page-action-add-to-urlbar =
+    .label = Ychwanegu i'r Llyfr Cyfeiriadau
+page-action-manage-extension =
+    .label = Rheoli Estyniad…
+page-action-remove-from-urlbar =
+    .label = Tynnu o'r Bar Cyfeiriadau
+page-action-remove-extension =
+    .label = Tynnu Estyniad
+
+## Page Action menu
+
+# Variables
+# $tabCount (integer) - Number of tabs selected
+page-action-send-tabs-panel =
+    .label =
+        { $tabCount ->
+            [zero] Anfon Tab i Ddyfais
+            [one] Anfon { $tabCount } Tab i Ddyfais
+            [two] Anfon { $tabCount } Dab i Ddyfais
+            [few] Anfon { $tabCount } Thab i Ddyfais
+            [many] Anfon { $tabCount } Tab i Ddyfais
+           *[other] Anfon { $tabCount } Thab i Ddyfais
+        }
+page-action-send-tabs-urlbar =
+    .tooltiptext =
+        { $tabCount ->
+            [zero] Anfon Tab i Ddyfais
+            [one] Anfon { $tabCount } Tab i Ddyfais
+            [two] Anfon { $tabCount } Dab i Ddyfais
+            [few] Anfon { $tabCount } Thab i Ddyfais
+            [many] Anfon { $tabCount } Tab i Ddyfais
+           *[other] Anfon { $tabCount } Thab i Ddyfais
+        }
+page-action-pocket-panel =
+    .label = Cadw Tudalen i { -pocket-brand-name }
+page-action-copy-url-panel =
+    .label = Copïo'r Ddolen
+page-action-copy-url-urlbar =
+    .tooltiptext = Copïo'r Ddolen
+page-action-email-link-panel =
+    .label = E-bostio'r Ddolen…
+page-action-email-link-urlbar =
+    .tooltiptext = E-bostio'r Ddolen…
+page-action-share-url-panel =
+    .label = Rhannu
+page-action-share-url-urlbar =
+    .tooltiptext = Rhannu
+page-action-share-more-panel =
+    .label = Rhagor…
+page-action-send-tab-not-ready =
+    .label = Cydweddu Dyfeisiau…
+# "Pin" is being used as a metaphor for expressing the fact that these tabs
+# are "pinned" to the left edge of the tabstrip. Really we just want the
+# string to express the idea that this is a lightweight and reversible
+# action that keeps your tab where you can reach it easily.
+page-action-pin-tab-panel =
+    .label = Pinio Tab
+page-action-pin-tab-urlbar =
+    .tooltiptext = Pinio Tab
+page-action-unpin-tab-panel =
+    .label = Dadbinio Tab
+page-action-unpin-tab-urlbar =
+    .tooltiptext = Dadbinio Tab
+
+## Auto-hide Context Menu
+
+full-screen-autohide =
+    .label = Cuddio Barrau Offer
+    .accesskey = u
+full-screen-exit =
+    .label = Gadael y Modd Sgrin Lawn
+    .accesskey = L
+
+## Search Engine selection buttons (one-offs)
+
+# This string prompts the user to use the list of search shortcuts in
+# the Urlbar and searchbar.
+search-one-offs-with-title = Y tro hwn, chwilio gyda:
+# This string won't wrap, so if the translated string is longer,
+# consider translating it as if it said only "Search Settings".
+search-one-offs-change-settings-button =
+    .label = Gosodiadau Chwilio
+search-one-offs-change-settings-compact-button =
+    .tooltiptext = Newid y gosodiadau chwilio
+search-one-offs-context-open-new-tab =
+    .label = Chwilio mewn Tab Newydd
+    .accesskey = T
+search-one-offs-context-set-as-default =
+    .label = Gosod fel y Peiriant Chwilio Rhagosodedig
+    .accesskey = R
+search-one-offs-context-set-as-default-private =
+    .label = Gosod fel y Peiriant Chwilio Rhagosodedig ar gyfer Windows Preifat
+    .accesskey = G
+# Search engine one-off buttons with an @alias shortcut/keyword.
+# Variables:
+#  $engineName (String): The name of the engine.
+#  $alias (String): The @alias shortcut/keyword.
+search-one-offs-engine-with-alias =
+    .tooltiptext = { $engineName } ({ $alias })
+
+## Local search mode one-off buttons
+## Variables:
+##  $restrict (String): The restriction token corresponding to the search mode.
+##    Restriction tokens are special characters users can type in the urlbar to
+##    restrict their searches to certain sources (e.g., "*" to search only
+##    bookmarks).
+
+search-one-offs-bookmarks =
+    .tooltiptext = Nodau tudalen ({ $restrict })
+search-one-offs-tabs =
+    .tooltiptext = Tabiau ({ $restrict })
+search-one-offs-history =
+    .tooltiptext = Hanes ({ $restrict })
+
+## Bookmark Panel
+
+bookmark-panel-show-editor-checkbox =
+    .label = Dangos y golygydd wrth gadw
+    .accesskey = D
+bookmark-panel-done-button =
+    .label = Gorffen
+# Width of the bookmark panel.
+# Should be large enough to fully display the Done and
+# Cancel/Remove Bookmark buttons.
+bookmark-panel =
+    .style = min-width: 23em
+
+## Identity Panel
+
+identity-connection-not-secure = Cysylltiad yn anniogel
+identity-connection-secure = Cysylltiad yn ddiogel
+identity-connection-internal = Mae hon yn dudalen { -brand-short-name } diogel.
+identity-connection-file = Mae'r dudalen hon wedi ei chadw ar eich cyfrifiadur.
+identity-extension-page = Mae'r dudalen wedi ei llwytho o estyniad.
+identity-active-blocked = Mae { -brand-short-name } wedi rhwystro rhannau o'r dudalen nad ydynt yn ddiogel.
+identity-custom-root = Dilyswyd y cysylltiad gan gyhoeddwr tystysgrif nad yw'n cael ei gydnabod gan Mozilla.
+identity-passive-loaded = Nid yw rhannau o'r dudalen hon yn ddiogel (megis delweddau).
+identity-active-loaded = Rydych wedi analluogi diogelwch ar y dudalen hon.
+identity-weak-encryption = Mae'r dudalen hon yn defnyddio amgryptiad gwan.
+identity-insecure-login-forms = Gall mewngofnodion sy'n cael eu cyflwyno ar y dudalen hon gael eu cyfaddawdu.
+identity-https-only-connection-upgraded = (wedi'i uwchraddio i HTTPS)
+identity-https-only-label = Modd HTTPS-yn-Unig
+identity-https-only-dropdown-on =
+    .label = Ymlaen
+identity-https-only-dropdown-off =
+    .label = Diffodd
+identity-https-only-dropdown-off-temporarily =
+    .label = Diffodd dros dro
+identity-https-only-info-turn-on2 = Trowch y Modd HTTPS-yn-Unig ymlaen os ydych chi am i { -brand-short-name } uwchraddio'r cysylltiad lle'n bosibl.
+identity-https-only-info-turn-off2 = Os yw'r wefan yn ymddangos wedi torri, efallai yr hoffech chi ddiffodd Modd HTTPS-yn-Unig i'w ail-lwytho gan ddefnyddio HTTP anniogel.
+identity-https-only-info-no-upgrade = Methu uwchraddio'r cysylltiad o HTTP.
+identity-permissions =
+    .value = Caniatâd
+identity-permissions-storage-access-header = Cwcis traws-gwefan
+identity-permissions-storage-access-hint = Gall y partïon hyn ddefnyddio cwcis traws-gwefan a data gwefan tra'ch bod chi ar y wefan hon.
+identity-permissions-reload-hint = Efallai y bydd angen ail lwytho'r dudalen i newidiadau ddod ar waith.
+identity-permissions-empty = Nid ydych wedi rhoi i'r wefan hon unrhyw ganiatâd arbennig.
+identity-clear-site-data =
+    .label = Clirio Data Cwcis a Gwefan…
+identity-connection-not-secure-security-view = Nid ydych wedi'ch cysylltu'n ddiogel â'r wefan hon.
+identity-connection-verified = Rydych wedi eich cysylltu'n ddiogel â'r wefan hon.
+identity-ev-owner-label = Tystysgrif wedi'i ryddhau i:
+identity-description-custom-root = Nid yw Mozilla yn cydnabod y cyhoeddwr tystysgrif hwn. Efallai ei fod wedi'i ychwanegu o'ch system weithredu neu gan weinyddwr. <label data-l10n-name="link">Dysgu Rhagor</label>
+identity-remove-cert-exception =
+    .label = Tynnu Eithriad
+    .accesskey = E
+identity-description-insecure = Nid yw eich cysylltiad â'r dudalen hon yn breifat. Gall gwybodaeth fyddwch yn ei gyflwyno cael ei weld gan eraill (megis cyfrineiriau, negeseuon, cardiau credyd, ac ati.).
+identity-description-insecure-login-forms = Nid yw'r manylion mewngofnodi rydych wedi ei roi i'r dudalen yn ddiogel a gall fod wedi ei danseilio.
+identity-description-weak-cipher-intro = Mae eich cysylltiad i'r wefan hon yn defnyddio amgryptiad gwan ac nid yw'n breifat.
+identity-description-weak-cipher-risk = Gall bobl eraill weld eich manylion neu newid ymddygiad y wefan.
+identity-description-active-blocked = Mae { -brand-short-name } wedi rhwystro rhannau o'r dudalen nad ydynt yn ddiogel. <label data-l10n-name="link">Dysgu Rhagor</label>
+identity-description-passive-loaded = Nid yw eich cysylltiad yn breifat ac mae'n bosib i wybodaeth rydych yn ei rannu gael ei weld gan eraill.
+identity-description-passive-loaded-insecure = Mae'r wefan yn cynnwys deunydd nad yw'n ddiogel (megis delweddau). <label data-l10n-name="link">Dysgu Rhagor</label>
+identity-description-passive-loaded-mixed = Er bod { -brand-short-name } wedi rhwystro peth cynnwys, mae cynnwys dal ar y dudalen nad yw'n ddiogel (megis delweddau). <label data-l10n-name="link">Dysgu Rhagor</label>
+identity-description-active-loaded = Mae'r wefan yn cynnwys yn deunydd nad yw'n ddiogel (megis sgriptiau) ac nid yw eich cysylltiad â nhw'n breifat.
+identity-description-active-loaded-insecure = Gall gwybodaeth fyddwch yn ei gyflwyno cael ei weld gan eraill (megis cyfrineiriau, negeseuon, cardiau credyd, ac ati.).
+identity-learn-more =
+    .value = Dysgu Rhagor
+identity-disable-mixed-content-blocking =
+    .label = Analluogi diogelu dros dro
+    .accesskey = A
+identity-enable-mixed-content-blocking =
+    .label = Galluogi diogelu
+    .accesskey = G
+identity-more-info-link-text =
+    .label = Rhagor o Wybodaeth
+
+## Window controls
+
+browser-window-minimize-button =
+    .tooltiptext = Lleihau
+browser-window-maximize-button =
+    .tooltiptext = Mwyhau
+browser-window-restore-down-button =
+    .tooltiptext = Adfer i Lawr
+browser-window-close-button =
+    .tooltiptext = Cau
+
+## Tab actions
+
+browser-tab-audio-playing = Chwarae
+browser-tab-audio-muted = Tewi
+
+## Bookmarks toolbar items
+
+browser-import-button2 =
+    .label = Mewnforio nodau tudalen…
+    .tooltiptext = Mewnforio nodau tudalen o borwr arall i { -brand-short-name }.
+bookmarks-toolbar-empty-message = I gael mynediad cyflym, rhowch eich nodau tudalen yma ar y bar offer nodau tudalen. <a data-l10n-name="manage-bookmarks"> Rheoli nodau tudalen…</a>
+
+## WebRTC Pop-up notifications
+
+popup-select-camera =
+    .value = Camera i'w rannu:
+    .accesskey = C
+popup-select-microphone =
+    .value = Meicroffon i'w rannu:
+    .accesskey = M
+popup-all-windows-shared = Bydd pob ffenestr gweladwy ar eich sgrin yn cael eu rhannu.
+popup-screen-sharing-not-now =
+    .label = Nid Nawr
+    .accesskey = N
+popup-screen-sharing-never =
+    .label = Byth Caniatáu
+    .accesskey = B
+popup-silence-notifications-checkbox = Analluogi hysbysiadau gan { -brand-short-name } wrth rannu
+popup-silence-notifications-checkbox-warning = Ni fydd { -brand-short-name } yn dangos hysbysiadau tra'ch bod chi'n rhannu.
+
+## WebRTC window or screen share tab switch warning
+
+sharing-warning-window = Rydych yn rhannu { -brand-short-name }. Gall pobl eraill weld pan fyddwch chi'n newid i dab newydd.
+sharing-warning-screen = Rydych chi'n rhannu'ch sgrin gyfan. Gall pobl eraill weld pan fyddwch chi'n newid i dab newydd.
+sharing-warning-proceed-to-tab =
+    .label = Ymlaen i Dab
+sharing-warning-disable-for-session =
+    .label = Analluogi diogelwch rhannu ar gyfer y sesiwn hon
+
+## DevTools F12 popup
+
+enable-devtools-popup-description = I ddefnyddio llwybr byr F12 agorwch DevTools yn gyntaf trwy'r ddewislen Datblygwr Gwe.
+
+## URL Bar
+
+urlbar-default-placeholder =
+    .defaultPlaceholder = Chwilio neu gyfeiriad gwe
+# This placeholder is used when not in search mode and the user's default search
+# engine is unknown.
+urlbar-placeholder =
+    .placeholder = Chwilio neu gyfeiriad gwe
+# This placeholder is used in search mode with search engines that search the
+# entire web.
+# Variables
+#  $name (String): the name of a search engine that searches the entire Web
+#  (e.g. Google).
+urlbar-placeholder-search-mode-web-2 =
+    .placeholder = Chwilio'r We
+    .aria-label = Chwilio gyda { $name }
+# This placeholder is used in search mode with search engines that search a
+# specific site (e.g., Amazon).
+# Variables
+#  $name (String): the name of a search engine that searches a specific site
+#  (e.g. Amazon).
+urlbar-placeholder-search-mode-other-engine =
+    .placeholder = Rhowch dermau chwilio
+    .aria-label = Chwilio { $name }
+# This placeholder is used when searching bookmarks.
+urlbar-placeholder-search-mode-other-bookmarks =
+    .placeholder = Rhowch dermau chwilio
+    .aria-label = Chwilio'r nodau tudalen
+# This placeholder is used when searching history.
+urlbar-placeholder-search-mode-other-history =
+    .placeholder = Rhowch dermau chwilio
+    .aria-label = Chwilio'ch hanes
+# This placeholder is used when searching open tabs.
+urlbar-placeholder-search-mode-other-tabs =
+    .placeholder = Rhowch dermau chwilio
+    .aria-label = Chwilio'r tabiau
+# Variables
+#  $name (String): the name of the user's default search engine
+urlbar-placeholder-with-name =
+    .placeholder = Chwilio gyda { $name } neu rhoi'r cyfeiriad
+urlbar-remote-control-notification-anchor =
+    .tooltiptext = Mae'r porwr o dan reolaeth bell
+urlbar-permissions-granted =
+    .tooltiptext = Rydych wedi rhoi caniatâd ychwanegol i'r wefan hon.
+urlbar-switch-to-tab =
+    .value = Newid i dab:
+# Used to indicate that a selected autocomplete entry is provided by an extension.
+urlbar-extension =
+    .value = Estyniad:
+urlbar-go-button =
+    .tooltiptext = Mynd i'r cyfeiriad yn y Bar Lleoliad
+urlbar-page-action-button =
+    .tooltiptext = Gweithredoedd tudalen
+urlbar-pocket-button =
+    .tooltiptext = Cadw i { -pocket-brand-name }
+
+## Action text shown in urlbar results, usually appended after the search
+## string or the url, like "result value - action text".
+
+# Used when the private browsing engine differs from the default engine.
+# The "with" format was chosen because the search engine name can end with
+# "Search", and we would like to avoid strings like "Search MSN Search".
+# Variables
+#  $engine (String): the name of a search engine
+urlbar-result-action-search-in-private-w-engine = Chwilio gyda { $engine } mewn Ffenestr Breifat
+# Used when the private browsing engine is the same as the default engine.
+urlbar-result-action-search-in-private = Chwilio mewn Ffenestr Breifat
+# The "with" format was chosen because the search engine name can end with
+# "Search", and we would like to avoid strings like "Search MSN Search".
+# Variables
+#  $engine (String): the name of a search engine
+urlbar-result-action-search-w-engine = Chwilio gyda { $engine }
+urlbar-result-action-sponsored = Noddwyd
+urlbar-result-action-switch-tab = Newid i'r Tab
+urlbar-result-action-visit = Ymweld â
+# Directs a user to press the Tab key to perform a search with the specified
+# engine.
+# Variables
+#  $engine (String): the name of a search engine that searches the entire Web
+#  (e.g. Google).
+urlbar-result-action-before-tabtosearch-web = Pwyswch Tab i chwilio gyda { $engine }
+# Directs a user to press the Tab key to perform a search with the specified
+# engine.
+# Variables
+#  $engine (String): the name of a search engine that searches a specific site
+#  (e.g. Amazon).
+urlbar-result-action-before-tabtosearch-other = Pwyswch Tab i chwilio { $engine }
+# Variables
+#  $engine (String): the name of a search engine that searches the entire Web
+#  (e.g. Google).
+urlbar-result-action-tabtosearch-web = Chwilio gyda { $engine } yn syth o'r bar cyfeiriad
+# Variables
+#  $engine (String): the name of a search engine that searches a specific site
+#  (e.g. Amazon).
+urlbar-result-action-tabtosearch-other-engine = Chwilio gyda { $engine } yn syth o'r bar cyfeiriad
+
+## Action text shown in urlbar results, usually appended after the search
+## string or the url, like "result value - action text".
+## In these actions "Search" is a verb, followed by where the search is performed.
+
+urlbar-result-action-search-bookmarks = Chwilio'r Nodau Tudalen
+urlbar-result-action-search-history = Chwilio'r Hanes
+urlbar-result-action-search-tabs = Chwilio'r Tabiau
+
+## Full Screen and Pointer Lock UI
+
+# Please ensure that the domain stays in the `<span data-l10n-name="domain">` markup.
+# Variables
+#  $domain (String): the domain that is full screen, e.g. "mozilla.org"
+fullscreen-warning-domain = <span data-l10n-name="domain">{ $domain }</span> nawr yn sgrin lawn
+fullscreen-warning-no-domain = Mae'r ddogfen nawr yn sgrin lawn
+fullscreen-exit-button = Gadael y Sgrin Lawn (Esc)
+# "esc" is lowercase on mac keyboards, but uppercase elsewhere.
+fullscreen-exit-mac-button = Gadael y Sgrin Lawn (esc)
+# Please ensure that the domain stays in the `<span data-l10n-name="domain">` markup.
+# Variables
+#  $domain (String): the domain that is using pointer-lock, e.g. "mozilla.org"
+pointerlock-warning-domain = <span data-l10n-name="domain">{ $domain }</span> reolaeth o'ch pwyntydd. Pwyswch Esc i adennill rheolaeth.
+pointerlock-warning-no-domain = Mae gan y ddogfen hon reolaeth o'ch pwyntydd. Pwyswch Esc i adennill rheolaeth.
+
+## Subframe crash notification
+
+crashed-subframe-message = <strong>Mae rhan o'r dudalen hon wedi chwalu.</strong> Er mwyn rhoi gwybod i { -brand-product-name } am y mater hwn a'i drwsio'n gynt, cyflwynwch adroddiad.
+crashed-subframe-learnmore =
+    .label = Dysgu rhagor
+    .accesskey = D
+crashed-subframe-submit =
+    .label = Cyflwyno Adroddiad
+    .accesskey = A
+
+## Bookmarks panels, menus and toolbar
+
+bookmarks-show-all-bookmarks =
+    .label = Dangos Pob Nod Tudalen
+bookmarks-recent-bookmarks =
+    .value = Wedi gosod Nod Tudalen yn Ddiweddar
+bookmarks-manage-bookmarks =
+    .label = Rheoli Nodau Tudalen
+bookmarks-recent-bookmarks-panel =
+    .value = Nodau Tudalen Diweddar
+bookmarks-toolbar-chevron =
+    .tooltiptext = Dangos pob ffolder nod tudalen
+bookmarks-sidebar-content =
+    .aria-label = Nodau Tudalen
+bookmarks-menu-button =
+    .label = Dewislen Nodau Tudalen
+bookmarks-other-bookmarks-menu =
+    .label = Nodau Tudalen Eraill
+bookmarks-mobile-bookmarks-menu =
+    .label = Nodau Tudalen Symudol
+bookmarks-tools-sidebar-visibility =
+    .label =
+        { $isVisible ->
+            [true] Cuddio'r Bar Ochr Nodau Tudalen
+           *[other] Gweld Bar Offer Nodau Tudalen
+        }
+bookmarks-tools-toolbar-visibility =
+    .label =
+        { $isVisible ->
+            [true] Cuddio'r Bar Offer Nodau Tudalen
+           *[other] Gweld Bar Offer Nodau Tudalen
+        }
+bookmarks-tools-toolbar-visibility-menuitem =
+    .label =
+        { $isVisible ->
+            [true] Cuddio'r Bar Offer Nodau Tudalen
+           *[other] Gweld Bar Offer Nodau Tudalen
+        }
+bookmarks-tools-toolbar-visibility-panel =
+    .label =
+        { $isVisible ->
+            [true] Cuddio'r Bar Offer Nodau Tudalen
+           *[other] Dangos y Bar Offer Nodau Tudalen
+        }
+bookmarks-tools-menu-button-visibility =
+    .label =
+        { $isVisible ->
+            [true] Tynnu Dewislen Nodau Tudalen o'r Bar Offer
+           *[other] Ychwanegu Dewislen Nodau Tudalen i'r Bar Offer
+        }
+bookmarks-search =
+    .label = Chwilio'r Nodau Tudalen
+bookmarks-tools =
+    .label = Offer Nodau Tudalen
+bookmarks-bookmark-edit-panel =
+    .label = Golygu'r Nod Tudalen
+# The aria-label is a spoken label that should not include the word "toolbar" or
+# such, because screen readers already know that this container is a toolbar.
+# This avoids double-speaking.
+bookmarks-toolbar =
+    .toolbarname = Bar Offer Nodau Tudalen
+    .accesskey = N
+    .aria-label = Nodau Tudalen
+bookmarks-toolbar-menu =
+    .label = Bar Offer Nodau Tudalen
+bookmarks-toolbar-placeholder =
+    .title = Eitemau Bar Offer Nodau Tudalen
+bookmarks-toolbar-placeholder-button =
+    .label = Eitemau Bar Offer Nodau Tudalen
+# "Bookmark" is a verb, as in "Add current tab to bookmarks".
+bookmarks-current-tab =
+    .label = Gosod Nod Tudalen i'r Tab Cyfredol
+
+## Library Panel items
+
+library-bookmarks-menu =
+    .label = Nodau Tudalen
+library-bookmarks-bookmark-this-page =
+    .label = Gosod Nod Tudalen i'r Dudalen
+library-bookmarks-bookmark-edit =
+    .label = Golygu'r Nod Tudalen
+library-recent-activity-title =
+    .value = Gweithgareddau Diweddar
+
+## More items
+
+more-menu-go-offline =
+    .label = Gweithio All-lein
+    .accesskey = w
diff --git a/l10n-cy/browser/browser/browserContext.ftl b/l10n-cy/browser/browser/browserContext.ftl
new file mode 100644
index 0000000000..0120567ccc
--- /dev/null
+++ b/l10n-cy/browser/browser/browserContext.ftl
@@ -0,0 +1,339 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+navbar-tooltip-instruction =
+    .value =
+        { PLATFORM() ->
+            [macos] Tynnu lawr i ddangos hanes
+           *[other] Clic de neu dynnu lawr i ddangos hanes
+        }
+
+## Back
+
+main-context-menu-back =
+    .tooltiptext = Nôl un tudalen
+    .aria-label = Nôl
+    .accesskey = N
+navbar-tooltip-back =
+    .value = { main-context-menu-back.tooltiptext }
+toolbar-button-back =
+    .label = { main-context-menu-back.aria-label }
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the Go Back command.
+main-context-menu-back-2 =
+    .tooltiptext = Nôl un tudalen ({ $shortcut })
+    .aria-label = Nôl
+    .accesskey = N
+navbar-tooltip-back-2 =
+    .value = { main-context-menu-back-2.tooltiptext }
+toolbar-button-back-2 =
+    .label = { main-context-menu-back-2.aria-label }
+
+## Forward
+
+main-context-menu-forward =
+    .tooltiptext = Ymlaen un tudalen
+    .aria-label = Ymlaen
+    .accesskey = Y
+navbar-tooltip-forward =
+    .value = { main-context-menu-forward.tooltiptext }
+toolbar-button-forward =
+    .label = { main-context-menu-forward.aria-label }
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the Go Forward command.
+main-context-menu-forward-2 =
+    .tooltiptext = Ymlaen un tudalen ({ $shortcut })
+    .aria-label = Ymlaen
+    .accesskey = Y
+navbar-tooltip-forward-2 =
+    .value = { main-context-menu-forward-2.tooltiptext }
+toolbar-button-forward-2 =
+    .label = { main-context-menu-forward-2.aria-label }
+
+## Reload
+
+main-context-menu-reload =
+    .aria-label = Ail-lwytho
+    .accesskey = A
+toolbar-button-reload =
+    .label = { main-context-menu-reload.aria-label }
+
+## Stop
+
+main-context-menu-stop =
+    .aria-label = Atal
+    .accesskey = t
+toolbar-button-stop =
+    .label = { main-context-menu-stop.aria-label }
+
+## Stop-Reload Button
+
+toolbar-button-stop-reload =
+    .title = { main-context-menu-reload.aria-label }
+
+## Save Page
+
+main-context-menu-page-save =
+    .label = Cadw Tudalen Fel…
+    .accesskey = T
+toolbar-button-page-save =
+    .label = { main-context-menu-page-save.label }
+
+## Simple menu items
+
+main-context-menu-bookmark-add =
+    .aria-label = Gosod Nod Tudalen i'r Dudalen
+    .accesskey = N
+    .tooltiptext = Gosod nod tudalen i'r dudalen
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the add bookmark command.
+main-context-menu-bookmark-add-with-shortcut =
+    .aria-label = Gosod Nod Tudalen i'r Dudalen
+    .accesskey = N
+    .tooltiptext = Gosod nod tudalen i'r dudalen ({ $shortcut })
+main-context-menu-bookmark-change =
+    .aria-label = Golygu'r Nod Tudalen
+    .accesskey = N
+    .tooltiptext = Golygu'r nod tudalen
+# Variables
+#   $shortcut (String) - A keyboard shortcut for the edit bookmark command.
+main-context-menu-bookmark-change-with-shortcut =
+    .aria-label = Golygu'r Nod Tudalen
+    .accesskey = N
+    .tooltiptext = Golygu'r nod tudalen ({ $shortcut })
+main-context-menu-open-link =
+    .label = Agor Dolen
+    .accesskey = D
+main-context-menu-open-link-new-tab =
+    .label = Agor Dolen mewn Tab Newydd
+    .accesskey = T
+main-context-menu-open-link-container-tab =
+    .label = Agor Dolen mewn Tab Cynhwysydd Newydd
+    .accesskey = T
+main-context-menu-open-link-new-window =
+    .label = Agor Dolen mewn Ffenestr Newydd
+    .accesskey = F
+main-context-menu-open-link-new-private-window =
+    .label = Agor Dolen mewn Ffenestr Breifat
+    .accesskey = F
+main-context-menu-bookmark-this-link =
+    .label = Gosod Nod Tudalen i'r Ddolen
+    .accesskey = D
+main-context-menu-save-link =
+    .label = Cadw'r Ddolen Fel…
+    .accesskey = a
+main-context-menu-save-link-to-pocket =
+    .label = Cadw Dolen i { -pocket-brand-name }
+    .accesskey = o
+
+## The access keys for "Copy Link Location" and "Copy Email Address"
+## should be the same if possible; the two context menu items
+## are mutually exclusive.
+
+main-context-menu-copy-email =
+    .label = Copïo Cyfeiriad E-bost
+    .accesskey = E
+main-context-menu-copy-link =
+    .label = Copïo Lleoliad Dolen
+    .accesskey = C
+
+## Media (video/audio) controls
+##
+## The accesskey for "Play" and "Pause" are the
+## same because the two context-menu items are
+## mutually exclusive.
+
+main-context-menu-media-play =
+    .label = Chwarae
+    .accesskey = C
+main-context-menu-media-pause =
+    .label = Oedi
+    .accesskey = O
+
+##
+
+main-context-menu-media-mute =
+    .label = Tewi
+    .accesskey = T
+main-context-menu-media-unmute =
+    .label = Dad-dewi
+    .accesskey = a
+main-context-menu-media-play-speed =
+    .label = Cyflymder Chwarae
+    .accesskey = y
+main-context-menu-media-play-speed-slow =
+    .label = Araf (0.5×)
+    .accesskey = A
+main-context-menu-media-play-speed-normal =
+    .label = Arferol
+    .accesskey = A
+main-context-menu-media-play-speed-fast =
+    .label = Cyflym (1.25×)
+    .accesskey = C
+main-context-menu-media-play-speed-faster =
+    .label = Cyflymach (1.5×)
+    .accesskey = y
+# "Ludicrous" is a reference to the movie "Space Balls" and is meant
+# to say that this speed is very fast.
+main-context-menu-media-play-speed-fastest =
+    .label = Hyrt (2×)
+    .accesskey = H
+main-context-menu-media-loop =
+    .label = Cylchu
+    .accesskey = C
+
+## The access keys for "Show Controls" and "Hide Controls" are the same
+## because the two context-menu items are mutually exclusive.
+
+main-context-menu-media-show-controls =
+    .label = Dangos Rheolydd
+    .accesskey = R
+main-context-menu-media-hide-controls =
+    .label = Cuddio Rheolydd
+    .accesskey = u
+
+##
+
+main-context-menu-media-video-fullscreen =
+    .label = Sgrin Lawn
+    .accesskey = S
+main-context-menu-media-video-leave-fullscreen =
+    .label = Gadael Sgrin Lawn
+    .accesskey = S
+# This is used when right-clicking on a video in the
+# content area when the Picture-in-Picture feature is enabled.
+main-context-menu-media-pip =
+    .label = Llun mewn Llun
+    .accesskey = L
+main-context-menu-image-reload =
+    .label = Ail-lwytho'r Ddelwedd
+    .accesskey = D
+main-context-menu-image-view =
+    .label = Edrych ar Ddelwedd
+    .accesskey = E
+main-context-menu-video-view =
+    .label = Gwylio Fideo
+    .accesskey = i
+main-context-menu-image-copy =
+    .label = Copïo Delwedd
+    .accesskey = D
+main-context-menu-image-copy-location =
+    .label = Copïo Lleoliad Delwedd
+    .accesskey = L
+main-context-menu-video-copy-location =
+    .label = Copïo Lleoliad Delwedd
+    .accesskey = e
+main-context-menu-audio-copy-location =
+    .label = Copïo Lleoliad Delwedd
+    .accesskey = a
+main-context-menu-image-save-as =
+    .label = Cadw Delwedd Fel…
+    .accesskey = D
+main-context-menu-image-email =
+    .label = Delwedd E-bost…
+    .accesskey = D
+main-context-menu-image-set-as-background =
+    .label = Gosod fel Cefndir Bwrdd Gwaith…
+    .accesskey = B
+main-context-menu-image-info =
+    .label = Gwybodaeth am Weld Delwedd
+    .accesskey = D
+main-context-menu-image-desc =
+    .label = Gweld Disgrifiad
+    .accesskey = D
+main-context-menu-video-save-as =
+    .label = Cadw Fideo Fel…
+    .accesskey = F
+main-context-menu-audio-save-as =
+    .label = Cadw Sain Fel…
+    .accesskey = C
+main-context-menu-video-image-save-as =
+    .label = Cadw Ciplun Fel…
+    .accesskey = i
+main-context-menu-video-email =
+    .label = Fideo E-bost…
+    .accesskey = F
+main-context-menu-audio-email =
+    .label = Sain E-bost…
+    .accesskey = S
+main-context-menu-plugin-play =
+    .label = Gweithredu'r ategyn
+    .accesskey = G
+main-context-menu-plugin-hide =
+    .label = Cuddio'r ategyn
+    .accesskey = C
+main-context-menu-save-to-pocket =
+    .label = Cadw Tudalen i { -pocket-brand-name }
+    .accesskey = k
+main-context-menu-send-to-device =
+    .label = Anfon Tudalen i Ddyfais
+    .accesskey = D
+main-context-menu-view-background-image =
+    .label = Edrych ar Ddelwedd Gefndir
+    .accesskey = G
+main-context-menu-generate-new-password =
+    .label = Defnyddio Cyfrinair wedi'i Gynhyrchu
+    .accesskey = G
+main-context-menu-keyword =
+    .label = Ychwanegu Allweddair i'r Chwilio…
+    .accesskey = Y
+main-context-menu-link-send-to-device =
+    .label = Anfon Dolen i Ddyfais
+    .accesskey = D
+main-context-menu-frame =
+    .label = Y Ffrâm
+    .accesskey = F
+main-context-menu-frame-show-this =
+    .label = Dangos y Ffrâm yma'n Unig
+    .accesskey = D
+main-context-menu-frame-open-tab =
+    .label = Agor Ffrâm mewn Tab Newydd
+    .accesskey = T
+main-context-menu-frame-open-window =
+    .label = Agor Ffrâm mewn Ffenestr Newydd
+    .accesskey = F
+main-context-menu-frame-reload =
+    .label = Ail-lwytho'r Ffrâm
+    .accesskey = r
+main-context-menu-frame-bookmark =
+    .label = Gosod Nod Tudalen i'r Ffrâm
+    .accesskey = F
+main-context-menu-frame-save-as =
+    .label = Cadw Ffrâm Fel…
+    .accesskey = F
+main-context-menu-frame-print =
+    .label = Argraffu'r Ffrâm…
+    .accesskey = A
+main-context-menu-frame-view-source =
+    .label = Edrych ar God Gwreiddiol y Ffrâm
+    .accesskey = F
+main-context-menu-frame-view-info =
+    .label = Edrych ar Wybodaeth am y Ffrâm
+    .accesskey = W
+main-context-menu-print-selection =
+    .label = Dewis Argraffu
+    .accesskey = A
+main-context-menu-view-selection-source =
+    .label = Edrych ar Ffynhonnell y Dewis
+    .accesskey = E
+main-context-menu-view-page-source =
+    .label = Edrych ar God Gwreiddiol y Dudalen
+    .accesskey = G
+main-context-menu-view-page-info =
+    .label = Edrych ar Wybodaeth am y Dudalen
+    .accesskey = E
+main-context-menu-bidi-switch-text =
+    .label = Newid Cyfeiriad Testun
+    .accesskey = T
+main-context-menu-bidi-switch-page =
+    .label = Newid Cyfeiriad Tudalen
+    .accesskey = N
+main-context-menu-inspect-element =
+    .label = Archwilio Elfen
+    .accesskey = E
+main-context-menu-inspect-a11y-properties =
+    .label = Archwilio'r Priodoleddau Hygyrchedd
+main-context-menu-eme-learn-more =
+    .label = Dysgu rhagor am DRM…
+    .accesskey = D
diff --git a/l10n-cy/browser/browser/browserSets.ftl b/l10n-cy/browser/browser/browserSets.ftl
new file mode 100644
index 0000000000..ccaaf36523
--- /dev/null
+++ b/l10n-cy/browser/browser/browserSets.ftl
@@ -0,0 +1,180 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+window-minimize-command =
+    .label = Lleihau
+window-zoom-command =
+    .label = Chwyddo
+window-new-shortcut =
+    .key = N
+window-minimize-shortcut =
+    .key = m
+close-shortcut =
+    .key = W
+tab-new-shortcut =
+    .key = t
+location-open-shortcut =
+    .key = l
+location-open-shortcut-alt =
+    .key = D
+search-focus-shortcut =
+    .key = k
+# This shortcut is used in two contexts:
+#   - web search
+#   - find in page
+find-shortcut =
+    .key = f
+search-find-again-shortcut =
+    .key = g
+search-find-again-shortcut-alt =
+    .keycode = VK_F3
+search-find-selection-shortcut =
+    .key = e
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+search-focus-shortcut-alt =
+    .key =
+        { PLATFORM() ->
+            [linux] j
+           *[other] e
+        }
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+downloads-shortcut =
+    .key =
+        { PLATFORM() ->
+            [linux] y
+           *[other] j
+        }
+addons-shortcut =
+    .key = A
+file-open-shortcut =
+    .key = o
+save-page-shortcut =
+    .key = s
+page-source-shortcut =
+    .key = u
+# This should match the Option+Command keyboard shortcut letter that Safari
+# and Chrome use for "View Source" on macOS. `page-source-shortcut` above
+# is Firefox's official keyboard shortcut shown in the GUI.
+# Safari variant is an alias provided for the convenience of Safari and Chrome
+# users on macOS. See bug 1398988.
+page-source-shortcut-safari =
+    .key = u
+page-info-shortcut =
+    .key = i
+print-shortcut =
+    .key = p
+mute-toggle-shortcut =
+    .key = M
+nav-back-shortcut-alt =
+    .key = [
+nav-fwd-shortcut-alt =
+    .key = ]
+nav-reload-shortcut =
+    .key = r
+# Shortcut available only on macOS.
+nav-stop-shortcut =
+    .key = .
+history-show-all-shortcut =
+    .key = H
+history-show-all-shortcut-mac =
+    .key = Y
+history-sidebar-shortcut =
+    .key = h
+full-screen-shortcut =
+    .key = F
+reader-mode-toggle-shortcut-windows =
+    .keycode = VK_F9
+reader-mode-toggle-shortcut-other =
+    .key = R
+picture-in-picture-toggle-shortcut-mac =
+    .key = ]
+# Pick the key that is commonly present
+# in your locale keyboards above the
+# `picture-in-picture-toggle-shortcut-mac` key.
+picture-in-picture-toggle-shortcut-mac-alt =
+    .key = { "}" }
+picture-in-picture-toggle-shortcut =
+    .key = ]
+# Pick the key that is commonly present
+# in your locale keyboards above the
+# `picture-in-picture-toggle-shortcut` key.
+picture-in-picture-toggle-shortcut-alt =
+    .key = { "}" }
+bookmark-this-page-shortcut =
+    .key = d
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+bookmark-show-all-shortcut =
+    .key =
+        { PLATFORM() ->
+            [linux] o
+           *[other] b
+        }
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+bookmark-show-library-shortcut =
+    .key = O
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+bookmark-show-sidebar-shortcut =
+    .key = b
+# Verify what shortcut for that operation
+# are recommended by the Human Interface Guidelines
+# of each platform for your locale.
+bookmark-show-toolbar-shortcut =
+    .key = B
+
+## All `-alt*` messages are alternative acceleration keys for zoom.
+## If shift key is needed with your locale popular keyboard for them,
+## you can use these alternative items. Otherwise, their values should be empty.
+
+full-zoom-reduce-shortcut =
+    .key = -
+# If in keyboard layouts popular for your locale you need to use the shift key
+# to access the original shortcuts, the following shortcuts can be used.
+# Otherwise their values should remain empty.
+full-zoom-reduce-shortcut-alt =
+    .key = { "" }
+full-zoom-reduce-shortcut-alt-a =
+    .key = _
+full-zoom-reduce-shortcut-alt-b =
+    .key = { "" }
+full-zoom-enlarge-shortcut =
+    .key = +
+full-zoom-enlarge-shortcut-alt =
+    .key = =
+full-zoom-enlarge-shortcut-alt2 =
+    .key = { "" }
+full-zoom-reset-shortcut =
+    .key = 0
+full-zoom-reset-shortcut-alt =
+    .key = { "" }
+
+##
+
+bidi-switch-direction-shortcut =
+    .key = X
+private-browsing-shortcut =
+    .key = P
+
+## The shortcuts below are for Mac specific
+## global menu.
+
+quit-app-shortcut =
+    .key = Q
+help-shortcut =
+    .key = ?
+preferences-shortcut =
+    .key = ,
+hide-app-shortcut =
+    .key = H
+hide-other-apps-shortcut =
+    .key = H
diff --git a/l10n-cy/browser/browser/customizeMode.ftl b/l10n-cy/browser/browser/customizeMode.ftl
new file mode 100644
index 0000000000..063d60aa09
--- /dev/null
+++ b/l10n-cy/browser/browser/customizeMode.ftl
@@ -0,0 +1,47 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+customize-mode-restore-defaults =
+    .label = Adfer y Rhagosodiadau
+customize-mode-menu-and-toolbars-header = Llusgwch eich hoff eitemau i'r bar offer neu'r ddewislen ychwanegol.
+customize-mode-overflow-list-title = Dewislen Gorlif
+customize-mode-uidensity =
+    .label = Dwysedd
+customize-mode-done =
+    .label = Gorffen
+customize-mode-lwthemes-menu-manage =
+    .label = Rheoli
+    .accesskey = R
+customize-mode-toolbars =
+    .label = Barrau Offer
+customize-mode-titlebar =
+    .label = Bar Teitl
+customize-mode-uidensity-menu-touch =
+    .label = Cyffwrdd
+    .accesskey = C
+    .tooltiptext = Cyffwrdd
+customize-mode-uidensity-auto-touch-mode-checkbox =
+    .label = Defnyddio Cyffwrdd ar gyfer y Modd Tabled
+customize-mode-extra-drag-space =
+    .label = Bwlch Llusgo
+customize-mode-lwthemes =
+    .label = Themâu
+customize-mode-overflow-list-description = Llusgwch a gollwng yr eitemau hyn yma i'w cadw o fewn cyrraedd ond allan o'ch bar offer…
+customize-mode-uidensity-menu-normal =
+    .label = Arferol
+    .accesskey = A
+    .tooltiptext = Arferol
+customize-mode-uidensity-menu-compact =
+    .label = Cywasgu
+    .accesskey = C
+    .tooltiptext = Crynhoi
+customize-mode-lwthemes-menu-get-more =
+    .label = Estyn Rhagor o Themâu
+    .accesskey = E
+customize-mode-undo-cmd =
+    .label = Dadwneud
+customize-mode-lwthemes-my-themes =
+    .value = Fy Thema
+customize-mode-touchbar-cmd =
+    .label = Cyfaddasu'r Bar Cyffwrdd…
diff --git a/l10n-cy/browser/browser/defaultBrowserNotification.ftl b/l10n-cy/browser/browser/defaultBrowserNotification.ftl
new file mode 100644
index 0000000000..289f641e6b
--- /dev/null
+++ b/l10n-cy/browser/browser/defaultBrowserNotification.ftl
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The question portion of the following message should have the <strong> and </strong> tags surrounding it.
+default-browser-notification-message = <strong>Gosodwch { -brand-short-name } fel eich porwr rhagosodedig? </strong>Cewch bori'n gyflym, yn ddiogel ac yn breifat pryd bynnag y byddwch yn defnyddio'r we.
+default-browser-notification-button =
+    .label = Gosod fel y Rhagosodiad
+    .accesskey = R
diff --git a/l10n-cy/browser/browser/downloads.ftl b/l10n-cy/browser/browser/downloads.ftl
new file mode 100644
index 0000000000..d602f3f968
--- /dev/null
+++ b/l10n-cy/browser/browser/downloads.ftl
@@ -0,0 +1,166 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## The title and aria-label attributes are used by screen readers to describe
+## the Downloads Panel.
+
+downloads-window =
+    .title = Llwythi
+downloads-panel =
+    .aria-label = Llwythi
+
+##
+
+# The style attribute has the width of the Downloads Panel expressed using
+# a CSS unit. The longest labels that should fit are usually those of
+# in-progress and blocked downloads.
+downloads-panel-list =
+    .style = width: 70ch
+
+downloads-cmd-pause =
+    .label = Oedi
+    .accesskey = O
+downloads-cmd-resume =
+    .label = Ailgychwyn
+    .accesskey = A
+downloads-cmd-cancel =
+    .tooltiptext = Diddymu
+downloads-cmd-cancel-panel =
+    .aria-label = Diddymu
+
+# This message is only displayed on Windows and Linux devices
+downloads-cmd-show-menuitem =
+    .label = Agor Ffolder Cynnwys
+    .accesskey = F
+
+# This message is only displayed on macOS devices
+downloads-cmd-show-menuitem-mac =
+    .label = Dangos yn Finder
+    .accesskey = F
+
+downloads-cmd-use-system-default =
+    .label = Agor yn Narllenydd System
+    .accesskey = N
+
+downloads-cmd-always-use-system-default =
+    .label = Agor Bob Tro mewn Darllenydd System
+    .accesskey = B
+
+downloads-cmd-show-button =
+    .tooltiptext =
+        { PLATFORM() ->
+            [macos] Dangos yn Finder
+           *[other] Agor Ffolder Cynnwys
+        }
+
+downloads-cmd-show-panel =
+    .aria-label =
+        { PLATFORM() ->
+            [macos] Dangos yn Finder
+           *[other] Agor Ffolder Cynnwys
+        }
+downloads-cmd-show-description =
+    .value =
+        { PLATFORM() ->
+            [macos] Dangos yn Finder
+           *[other] Agor Ffolder Cynnwys
+        }
+
+downloads-cmd-show-downloads =
+    .label = Dangos y Ffowleder Llwythi
+downloads-cmd-retry =
+    .tooltiptext = Ceisio eto
+downloads-cmd-retry-panel =
+    .aria-label = Ceisio eto
+downloads-cmd-go-to-download-page =
+    .label = Mynd i'r Dudalen Llwytho i Lawr
+    .accesskey = M
+downloads-cmd-copy-download-link =
+    .label = Copïo Dolen Llwytho i Lawr
+    .accesskey = C
+downloads-cmd-remove-from-history =
+    .label = Tynnu o'r Hanes
+    .accesskey = y
+downloads-cmd-clear-list =
+    .label = Clirio'r Panel Rhagolwg
+    .accesskey = r
+downloads-cmd-clear-downloads =
+    .label = Clirio Llwythi
+    .accesskey = L
+
+# This command is shown in the context menu when downloads are blocked.
+downloads-cmd-unblock =
+    .label = Caniatáu Llwytho i Lawr
+    .accesskey = a
+
+# This is the tooltip of the action button shown when malware is blocked.
+downloads-cmd-remove-file =
+    .tooltiptext = Tynnu Ffeil
+
+downloads-cmd-remove-file-panel =
+    .aria-label = Tynnu Ffeil
+
+# This is the tooltip of the action button shown when potentially unwanted
+# downloads are blocked. This opens a dialog where the user can choose
+# whether to unblock or remove the download. Removing is the default option.
+downloads-cmd-choose-unblock =
+    .tooltiptext = Tynnu Ffeil neu Ganiatáu Llwytho i Lawr
+
+downloads-cmd-choose-unblock-panel =
+    .aria-label = Tynnu Ffeil neu Ganiatáu Llwytho i Lawr
+
+# This is the tooltip of the action button shown when uncommon downloads are
+# blocked.This opens a dialog where the user can choose whether to open the
+# file or remove the download. Opening is the default option.
+downloads-cmd-choose-open =
+    .tooltiptext = Agor neu Dynnu'r Ffeil
+
+downloads-cmd-choose-open-panel =
+    .aria-label = Agor neu Dynnu'r Ffeil
+
+# Displayed when hovering a blocked download, indicates that it's possible to
+# show more information for user to take the next action.
+downloads-show-more-information =
+    .value = Dangos rhagor o wybodaeth
+
+# Displayed when hovering a complete download, indicates that it's possible to
+# open the file using an app available in the system.
+downloads-open-file =
+    .value = Agor Ffeil
+
+# Displayed when hovering a download which is able to be retried by users,
+# indicates that it's possible to download this file again.
+downloads-retry-download =
+    .value = Ceisio Llwytho i Lawr Eto
+
+# Displayed when hovering a download which is able to be cancelled by users,
+# indicates that it's possible to cancel and stop the download.
+downloads-cancel-download =
+    .value = Diddymu Llwytho i Lawr
+
+# This string is shown at the bottom of the Downloads Panel when all the
+# downloads fit in the available space, or when there are no downloads in
+# the panel at all.
+downloads-history =
+    .label = Dangos Pob Llwyth
+    .accesskey = D
+
+# This string is shown at the top of the Download Details Panel, to indicate
+# that we are showing the details of a single download.
+downloads-details =
+    .title = Manylion y Llwytho i Lawr
+
+downloads-clear-downloads-button =
+    .label = Clirio'r Llwythi
+    .tooltiptext = Yn clirio llwythi cwblhawyd, dilëwyd a methwyd
+
+# This string is shown when there are no items in the Downloads view, when it
+# is displayed inside a browser tab.
+downloads-list-empty =
+    .value = Nid oes llwythi.
+
+# This string is shown when there are no items in the Downloads Panel.
+downloads-panel-empty =
+    .value = Dim llwytho i lawr yn ystod y sesiwn yma.
diff --git a/l10n-cy/browser/browser/editBookmarkOverlay.ftl b/l10n-cy/browser/browser/editBookmarkOverlay.ftl
new file mode 100644
index 0000000000..620cdafac6
--- /dev/null
+++ b/l10n-cy/browser/browser/editBookmarkOverlay.ftl
@@ -0,0 +1,42 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+bookmark-overlay-name =
+    .value = Enw:
+    .accesskey = E
+
+bookmark-overlay-location =
+    .value = Lleoliad:
+    .accesskey = L
+
+bookmark-overlay-folder =
+    .value = Ffolder:
+
+bookmark-overlay-choose =
+    .label = Dewis…
+
+bookmark-overlay-folders-expander =
+    .tooltiptext = Dangos pob ffolder nod tudalen
+    .tooltiptextdown = { bookmark-overlay-folders-expander.tooltiptext }
+    .tooltiptextup = Cuddio
+
+bookmark-overlay-new-folder-button =
+    .label = Ffolder Newydd
+    .accesskey = N
+
+bookmark-overlay-tags =
+    .value = Tagiau:
+    .accesskey = T
+
+bookmark-overlay-tags-empty-description =
+    .placeholder = Gwahanu tagiau gydag atalnod
+
+bookmark-overlay-tags-expander =
+    .tooltiptext = Dangos pob tag
+    .tooltiptextdown = { bookmark-overlay-tags-expander.tooltiptext }
+    .tooltiptextup = Cuddio
+
+bookmark-overlay-keyword =
+    .value = Allweddair:
+    .accesskey = A
diff --git a/l10n-cy/browser/browser/menubar.ftl b/l10n-cy/browser/browser/menubar.ftl
new file mode 100644
index 0000000000..ec88a93ed4
--- /dev/null
+++ b/l10n-cy/browser/browser/menubar.ftl
@@ -0,0 +1,347 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# NOTE: For English locales, strings in this file should be in APA-style Title Case.
+# See https://apastyle.apa.org/style-grammar-guidelines/capitalization/title-case
+#
+# NOTE: For Engineers, please don't re-use these strings outside of the menubar.
+
+
+## Application Menu (macOS only)
+
+menu-application-services =
+    .label = Gwasanaethau
+menu-application-hide-this =
+    .label = Cuddio { -brand-shorter-name }
+menu-application-hide-other =
+    .label = Cuddio Eraill
+menu-application-show-all =
+    .label = Dangos Popeth
+menu-application-touch-bar =
+    .label = Cyfaddasu'r Bar Cyffwrdd…
+
+##
+
+# These menu-quit strings are only used on Windows and Linux.
+menu-quit =
+    .label =
+        { PLATFORM() ->
+            [windows] Gadael
+           *[other] Gadael
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [windows] G
+           *[other] G
+        }
+# This menu-quit-mac string is only used on macOS.
+menu-quit-mac =
+    .label = Gadael { -brand-shorter-name }
+# This menu-quit-button string is only used on Linux.
+menu-quit-button =
+    .label = { menu-quit.label }
+# This menu-quit-button-win string is only used on Windows.
+menu-quit-button-win =
+    .label = { menu-quit.label }
+    .tooltip = Gadael { -brand-shorter-name }
+menu-about =
+    .label = Ynghylch { -brand-shorter-name }
+    .accesskey = n
+
+## File Menu
+
+menu-file =
+    .label = Ffeil
+    .accesskey = F
+menu-file-new-tab =
+    .label = Tab Newydd
+    .accesskey = T
+menu-file-new-container-tab =
+    .label = Tab Cynhwysydd Newydd
+    .accesskey = y
+menu-file-new-window =
+    .label = Ffenestr Newydd
+    .accesskey = N
+menu-file-new-private-window =
+    .label = Ffenestr Breifat Newydd
+    .accesskey = B
+# "Open Location" is only displayed on macOS, and only on windows
+# that aren't main browser windows, or when there are no windows
+# but Firefox is still running.
+menu-file-open-location =
+    .label = Agor Lleoliad…
+menu-file-open-file =
+    .label = Agor Ffeil…
+    .accesskey = F
+menu-file-close =
+    .label = Cau
+    .accesskey = C
+menu-file-close-window =
+    .label = Cau Ffenestr
+    .accesskey = F
+menu-file-save-page =
+    .label = Cadw Tudalen Fel…
+    .accesskey = C
+menu-file-email-link =
+    .label = E-bostio'r Ddolen…
+    .accesskey = E
+menu-file-print-setup =
+    .label = Gosodiad Tudalen…
+    .accesskey = o
+menu-file-print-preview =
+    .label = Rhagolwg Argraffu
+    .accesskey = R
+menu-file-print =
+    .label = Argraffu…
+    .accesskey = A
+menu-file-import-from-another-browser =
+    .label = Mewnforio o Borwr Arall…
+    .accesskey = M
+menu-file-go-offline =
+    .label = Gweithio All-lein
+    .accesskey = w
+
+## Edit Menu
+
+menu-edit =
+    .label = Golygu
+    .accesskey = G
+menu-edit-find-on =
+    .label = Canfod ar y Dudalen…
+    .accesskey = a
+menu-edit-find-again =
+    .label = Canfod Eto
+    .accesskey = E
+menu-edit-bidi-switch-text-direction =
+    .label = Newid Cyfeiriad Testun
+    .accesskey = T
+
+## View Menu
+
+menu-view =
+    .label = Golwg
+    .accesskey = o
+menu-view-toolbars-menu =
+    .label = Barrau Offer
+    .accesskey = B
+menu-view-customize-toolbar =
+    .label = Cyfaddasu…
+    .accesskey = y
+menu-view-sidebar =
+    .label = Bar Ochr
+    .accesskey = B
+menu-view-bookmarks =
+    .label = Nodau Tudalen
+menu-view-history-button =
+    .label = Hanes
+menu-view-synced-tabs-sidebar =
+    .label = Tabiau wedi'u Cydweddu
+menu-view-full-zoom =
+    .label = Chwyddo
+    .accesskey = h
+menu-view-full-zoom-enlarge =
+    .label = Chwyddo Mewn
+    .accesskey = M
+menu-view-full-zoom-reduce =
+    .label = Chwyddo Allan
+    .accesskey = A
+menu-view-full-zoom-actual-size =
+    .label = Maint Gwirioneddol
+    .accesskey = M
+menu-view-full-zoom-toggle =
+    .label = Chwyddo'r Testun yn Unig
+    .accesskey = T
+menu-view-page-style-menu =
+    .label = Arddull Tudalen
+    .accesskey = A
+menu-view-page-style-no-style =
+    .label = Dim Arddull
+    .accesskey = D
+menu-view-page-basic-style =
+    .label = Arddull Tudalen Sylfaenol
+    .accesskey = S
+menu-view-charset =
+    .label = Amgodiad Testun
+    .accesskey = T
+
+## These should match what Safari and other Apple applications
+## use on macOS.
+
+menu-view-enter-full-screen =
+    .label = Mynd i Sgrin Lawn
+    .accesskey = S
+menu-view-exit-full-screen =
+    .label = Gadael Sgrin Lawn
+    .accesskey = L
+menu-view-full-screen =
+    .label = Sgrin Lawn
+    .accesskey = S
+
+##
+
+menu-view-show-all-tabs =
+    .label = Dangos Pob Tab
+    .accesskey = a
+menu-view-bidi-switch-page-direction =
+    .label = Newid Cyfeiriad Tudalen
+    .accesskey = N
+
+## History Menu
+
+menu-history =
+    .label = Hanes
+    .accesskey = H
+menu-history-show-all-history =
+    .label = Dangos yr Holl Hanes
+menu-history-clear-recent-history =
+    .label = Clirio Hanes Diweddar…
+menu-history-synced-tabs =
+    .label = Tabiau wedi'u Cydweddu
+menu-history-restore-last-session =
+    .label = Adfer y Sesiwn Flaenorol
+menu-history-hidden-tabs =
+    .label = Tabiau Cudd
+menu-history-undo-menu =
+    .label = Tabiau Wedi eu Cau'n Ddiweddar
+menu-history-undo-window-menu =
+    .label = Ffenestri wedi eu Cau yn Ddiweddar
+
+## Bookmarks Menu
+
+menu-bookmarks-menu =
+    .label = Nodau Tudalen
+    .accesskey = T
+menu-bookmarks-show-all =
+    .label = Dangos Pob Nod Tudalen
+menu-bookmark-this-page =
+    .label = Gosod Nod Tudalen i'r Dudalen
+menu-bookmark-edit =
+    .label = Golygu'r Nod Tudalen
+menu-bookmarks-all-tabs =
+    .label = Nod Tudalen i Bob Tab…
+menu-bookmarks-toolbar =
+    .label = Bar Offer Nodau Tudalen
+menu-bookmarks-other =
+    .label = Nodau Tudalen Eraill
+menu-bookmarks-mobile =
+    .label = Nodau Tudalen Symudol
+
+## Tools Menu
+
+menu-tools =
+    .label = Offer
+    .accesskey = f
+menu-tools-downloads =
+    .label = Llwytho i Lawr
+    .accesskey = L
+menu-tools-addons =
+    .label = Ychwanegion
+    .accesskey = Y
+menu-tools-fxa-sign-in =
+    .label = Mewngofnodi i { -brand-product-name }…
+    .accesskey = M
+menu-tools-turn-on-sync =
+    .label = Cychwyn { -sync-brand-short-name }…
+    .accesskey = C
+menu-tools-sync-now =
+    .label = Cydweddu Nawr
+    .accesskey = y
+menu-tools-fxa-re-auth =
+    .label = Ailgysylltu â { -brand-product-name }…
+    .accesskey = A
+menu-tools-web-developer =
+    .label = Datblygwr Gwe
+    .accesskey = D
+menu-tools-page-source =
+    .label = Cod Gwreiddiol y Dudalen
+    .accesskey = o
+menu-tools-page-info =
+    .label = Gwybodaeth am y Dudalen
+    .accesskey = w
+menu-preferences =
+    .label =
+        { PLATFORM() ->
+            [windows] Opsiynau
+           *[other] Dewisiadau
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [windows] O
+           *[other] w
+        }
+menu-tools-layout-debugger =
+    .label = Dadfygiwr Dyluniad
+    .accesskey = D
+
+## Window Menu
+
+menu-window-menu =
+    .label = Ffenestr
+menu-window-bring-all-to-front =
+    .label = Dwyn y Cyfan i'r Blaen
+
+## Help Menu
+
+
+# NOTE: For Engineers, any additions or changes to Help menu strings should
+# also be reflected in the related strings in appmenu.ftl. Those strings, by
+# convention, will have the same ID as these, but prefixed with "app".
+# Example: appmenu-help-product
+#
+# These strings are duplicated to allow for different casing depending on
+# where the strings appear.
+
+
+# NOTE: For Engineers, any additions or changes to Help menu strings should
+# also be reflected in the related strings in appmenu.ftl. Those strings, by
+# convention, will have the same ID as these, but prefixed with "app".
+# Example: appmenu-get-help
+#
+# These strings are duplicated to allow for different casing depending on
+# where the strings appear.
+
+menu-help =
+    .label = Cymorth
+    .accesskey = C
+menu-help-product =
+    .label = Cymorth { -brand-shorter-name }
+    .accesskey = m
+menu-help-show-tour =
+    .label = Cyflwyno { -brand-shorter-name }
+    .accesskey = C
+menu-help-import-from-another-browser =
+    .label = Mewnforio o Borwr arall ...
+    .accesskey = M
+menu-help-keyboard-shortcuts =
+    .label = Llwybrau Byr Bysellfwrdd
+    .accesskey = B
+menu-get-help =
+    .label = Derbyn Cymorth
+    .accesskey = D
+menu-help-troubleshooting-info =
+    .label = Gwybodaeth am Ddatrys Problemau
+    .accesskey = G
+menu-help-taskmanager =
+    .label = Rheolwr Tasgau
+menu-help-feedback-page =
+    .label = Cyflwyno Adborth…
+    .accesskey = A
+menu-help-safe-mode-without-addons =
+    .label = Ailgychwyn gydag Ychwanegion wedi eu Hanalluogi…
+    .accesskey = A
+menu-help-safe-mode-with-addons =
+    .label = Ailgychwyn gydag Ychwanegion wedi eu Hanalluogi
+    .accesskey = A
+# Label of the Help menu item. Either this or
+# menu-help-notdeceptive is shown.
+menu-help-report-deceptive-site =
+    .label = Adroddwch ar wefan twyllodrus…
+    .accesskey = t
+menu-help-not-deceptive =
+    .label = Nid yw hon yn wefan twyllodrus…
+    .accesskey = t
+menu-help-check-for-update =
+    .label = Gwirio am Ddiweddariadau…
+    .accesskey = G
diff --git a/l10n-cy/browser/browser/migration.ftl b/l10n-cy/browser/browser/migration.ftl
new file mode 100644
index 0000000000..af234276de
--- /dev/null
+++ b/l10n-cy/browser/browser/migration.ftl
@@ -0,0 +1,148 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+migration-wizard =
+    .title = Dewin Mewnforio
+import-from =
+    { PLATFORM() ->
+        [windows] Mewnforio Opsiynau, Nodau Tudalen, Hanes, Cyfrineiriau, a data arall o:
+       *[other] Mewnforio Dewisiadau, Nodau Tudalen, Hanes, Cyfrineiriau a data arall o:
+    }
+import-from-bookmarks = Mewnforio Nodau Tudalen o:
+import-from-ie =
+    .label = Microsoft Internet Explorer
+    .accesskey = M
+import-from-edge =
+    .label = Microsoft Edge
+    .accesskey = E
+import-from-edge-legacy =
+    .label = Yr Hen Microsoft Edge
+    .accesskey = H
+import-from-edge-beta =
+    .label = Microsoft Edge Beta
+    .accesskey = d
+import-from-nothing =
+    .label = Peidio mewnforio dim
+    .accesskey = d
+import-from-safari =
+    .label = Safari
+    .accesskey = S
+import-from-canary =
+    .label = Chrome Canary
+    .accesskey = n
+import-from-chrome =
+    .label = Chrome
+    .accesskey = C
+import-from-chrome-beta =
+    .label = Chrome Beta
+    .accesskey = B
+import-from-chrome-dev =
+    .label = Chrome Dev
+    .accesskey = D
+import-from-chromium =
+    .label = Chromium
+    .accesskey = u
+import-from-firefox =
+    .label = Firefox
+    .accesskey = x
+import-from-360se =
+    .label = 360 Porwr Diogel
+    .accesskey = 3
+no-migration-sources = Methu canfod unrhyw rhaglenni sy'n cynnwys nodau tudalen, hanes na data cyfrineiriau.
+import-source-page-title = Gosodiadau Mewnforio a Data
+import-items-page-title = Eitemau i'w Mewnforio
+import-items-description = Dewis eitemau i'w mewnforio:
+import-permissions-page-title = Rhowch ganiatâd i { -brand-short-name }
+# Do not translate "Bookmarks.plist"; the file name is the same everywhere.
+import-permissions-description = Mae macOS yn gofyn i chi ganiatáu’n benodol i { -brand-short-name } gael mynediad i nodau tudalen Safari. Cliciwch “Continue” a dewiswch y ffeil “Bookmarks.plist” yn y panel File Open sy'n ymddangos.
+import-migrating-page-title = Mewnforio…
+import-migrating-description = Mae'r eitemau canlynol yn cael eu mewnforio…
+import-select-profile-page-title = Dewis Proffil
+import-select-profile-description = Mae'r proffiliau canlynol ar gael i'w mewnforio o:
+import-done-page-title = Wedi Cwblhau Mewnforio
+import-done-description = Cafodd yr eitemau canlynol eu mewnforio'n llwyddiannus:
+import-close-source-browser = Gwnewch yn siŵr fod y porwr wedi ei gau cyn parhau.
+# Displays which browser the bookmarks are being imported from
+#
+# Variables:
+#   $source (String): The browser the user has chosen to import bookmarks from.
+imported-bookmarks-source = O { $source }
+source-name-ie = Internet Explorer
+source-name-edge = Microsoft Edge
+source-name-edge-beta = Microsoft Edge Beta
+source-name-safari = Safari
+source-name-canary = Google Chrome Canary
+source-name-chrome = Google Chrome
+source-name-chrome-beta = Google Chrome Beta
+source-name-chrome-dev = Google Chrome Dev
+source-name-chromium = Chromium
+source-name-firefox = Mozilla Firefox
+source-name-360se = 360 Porwr Diogel
+imported-safari-reading-list = Rhestr Darllen (O Safari)
+imported-edge-reading-list = Rhestr Darllen (O Edge)
+
+## Browser data types
+## All of these strings get a $browser variable passed in.
+## You can use the browser variable to differentiate the name of items,
+## which may have different labels in different browsers.
+## The supported values for the $browser variable are:
+## 360se
+## chrome
+## edge
+## firefox
+## ie
+## safari
+## The various beta and development versions of edge and chrome all get
+## normalized to just "edge" and "chrome" for these strings.
+
+browser-data-cookies-checkbox =
+    .label = Cwcis
+browser-data-cookies-label =
+    .value = Cwcis
+browser-data-history-checkbox =
+    .label =
+        { $browser ->
+            [firefox] Hanes Pori a Nodau Tudalen
+           *[other] Hanes Pori
+        }
+browser-data-history-label =
+    .value =
+        { $browser ->
+            [firefox] Hanes Pori a Nodau Tudalen
+           *[other] Hanes Pori
+        }
+browser-data-formdata-checkbox =
+    .label = Hanes Ffurflenni wedi'u Cadw
+browser-data-formdata-label =
+    .value = Hanes Ffurflenni wedi'u Cadw
+# This string should use the same phrase for "logins and passwords" as the
+# label in the main hamburger menu that opens about:logins.
+browser-data-passwords-checkbox =
+    .label = Mewngofnodion a Chyfrineiriau wedi'u Cadw
+# This string should use the same phrase for "logins and passwords" as the
+# label in the main hamburger menu that opens about:logins.
+browser-data-passwords-label =
+    .value = Mewngofnodion a Chyfrineiriau wedi'u Cadw
+browser-data-bookmarks-checkbox =
+    .label =
+        { $browser ->
+            [ie] Ffefrynnau
+            [edge] Ffefrynnau
+           *[other] Nodau Tudalen
+        }
+browser-data-bookmarks-label =
+    .value =
+        { $browser ->
+            [ie] Ffefrynnau
+            [edge] Ffefrynnau
+           *[other] Nodau Tudalen
+        }
+browser-data-otherdata-checkbox =
+    .label = Data Arall
+browser-data-otherdata-label =
+    .label = Data Arall
+browser-data-session-checkbox =
+    .label = Ffenestri a Thabiau
+browser-data-session-label =
+    .value = Ffenestri a Thabiau
diff --git a/l10n-cy/browser/browser/newInstallPage.ftl b/l10n-cy/browser/browser/newInstallPage.ftl
new file mode 100644
index 0000000000..12d5b8bf2d
--- /dev/null
+++ b/l10n-cy/browser/browser/newInstallPage.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### For this feature, "installation" is used to mean "this discrete download of
+### Firefox" and "version" is used to mean "the specific revision number of a
+### given Firefox channel". These terms are not synonymous.
+
+title = Newyddion Pwysig
+heading = Newidiadau i'ch proffil { -brand-short-name }
+
+changed-title = Beth sydd wedi newid?
+changed-desc-profiles = Mae gan y gosodiad hwn o { -brand-short-name } broffil newydd. Proffil yw'r set o ffeiliau lle mae Firefox yn cadw gwybodaeth megis nodau tudalen, cyfrineiriau a dewisiadau defnyddwyr.
+changed-desc-dedicated = Er mwyn ei gwneud hi'n haws ac yn fwy diogel newid rhwng gosodiadau Firefox (gan gynnwys Firefox, Firefox ESR, Firefox Beta, Firefox Developer Edition, a Firefox Nightly), mae gan y gosodiad hwn broffil penodol. Nid yw'n cadw eich gwybodaeth wedi'u cadw yng ngosodiadau Firefox eraill yn awtomatig.
+
+lost = <b> Nid ydych chi wedi colli unrhyw ddata personol na chyfaddasiadau.</b> Os ydych eisoes wedi cadw gwybodaeth i Firefox ar y cyfrifiadur hwn, mae'n dal ar gael mewn gosodiad Firefox eraill.
+
+options-title = Beth yw fy newisiadau?
+options-do-nothing = Os na wnewch chi ddim byd, bydd eich data proffil yn { -brand-short-name } yn wahanol i ddata proffil mewn gosodiadau eraill o Firefox.
+options-use-sync = Os hoffech i'ch holl ddata proffil fod yr un peth ar bob gosodiad o Firefox, gallwch ddefnyddio { -fxaccount-brand-name } i'w cadw wedi'u cydweddu.
+
+resources = Adnoddau:
+support-link = Defnyddio'r Rheolwr Proffil - Erthygl Gymorth
+
+sync-header = Mewngofnodi neu greu { -fxaccount-brand-name }
+sync-label = Rhowch eich e-bost
+sync-input =
+    .placeholder = E-bost
+sync-button = Parhau
+sync-terms = Drwy barhau, rydych yn cytuno i'r <a data-l10n-name="terms">>Amodau Gwasanaeth</a> a'r <a data-l10n-name="privacy">Hysbysiad Preifatrwydd</a>.
+sync-first = Y tro cyntaf i ddefnyddio { -sync-brand-name }? Bydd angen i chi fewngofnodi i bob gosodiad o Firefox i gydweddu eich manylion.
+sync-learn = Dysgu rhagor
diff --git a/l10n-cy/browser/browser/newtab/asrouter.ftl b/l10n-cy/browser/browser/newtab/asrouter.ftl
new file mode 100644
index 0000000000..e80f861007
--- /dev/null
+++ b/l10n-cy/browser/browser/newtab/asrouter.ftl
@@ -0,0 +1,330 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## These messages are used as headings in the recommendation doorhanger
+
+cfr-doorhanger-extension-heading = Estyniadau Cymeradwy
+cfr-doorhanger-feature-heading = Nodwedd Cymeradwy
+cfr-doorhanger-pintab-heading = Profi hwn: Pinio Tab
+
+##
+
+cfr-doorhanger-extension-sumo-link =
+    .tooltiptext = Pam ydw i'n gweld hyn
+cfr-doorhanger-extension-cancel-button = Nid Nawr
+    .accesskey = N
+cfr-doorhanger-extension-ok-button = Ychwanegu Nawr
+    .accesskey = Y
+cfr-doorhanger-pintab-ok-button = Pinio'r Tab
+    .accesskey = P
+cfr-doorhanger-extension-manage-settings-button = Gosodiadau Argymell Rheoli
+    .accesskey = R
+cfr-doorhanger-extension-never-show-recommendation = Peidio Dangos yr Argymhelliad i Mi
+    .accesskey = P
+cfr-doorhanger-extension-learn-more-link = Dysgu rhagor
+# This string is used on a new line below the add-on name
+# Variables:
+#   $name (String) - Add-on author name
+cfr-doorhanger-extension-author = gan { $name }
+# This is a notification displayed in the address bar.
+# When clicked it opens a panel with a message for the user.
+cfr-doorhanger-extension-notification = Argymhelliad
+cfr-doorhanger-extension-notification2 = Argymhelliad
+    .tooltiptext = Argymhelliad Estyniad
+    .a11y-announcement = Mae argymhelliad estyniad ar gael
+# This is a notification displayed in the address bar.
+# When clicked it opens a panel with a message for the user.
+cfr-doorhanger-feature-notification = Argymhelliad
+    .tooltiptext = Argymhelliad Nodwedd
+    .a11y-announcement = Mae argymhelliad nodwedd ar gael
+
+## Add-on statistics
+## These strings are used to display the total number of
+## users and rating for an add-on. They are shown next to each other.
+
+# Variables:
+#   $total (Number) - The rating of the add-on from 1 to 5
+cfr-doorhanger-extension-rating =
+    .tooltiptext =
+        { $total ->
+            [zero] { $total } seren
+            [one] { $total } seren
+            [two] { $total } seren
+            [few] { $total } seren
+            [many] { $total } seren
+           *[other] { $total } seren
+        }
+# Variables:
+#   $total (Number) - The total number of users using the add-on
+cfr-doorhanger-extension-total-users =
+    { $total ->
+        [zero] { $total } defnyddiwr
+        [one] { $total } defnyddiwr
+        [two] { $total } ddefnyddiwr
+        [few] { $total } defnyddiwr
+        [many] { $total } defnyddiwr
+       *[other] { $total } defnyddiwr
+    }
+cfr-doorhanger-pintab-description = Cael mynediad hawdd i'ch hoff wefannau. Cadwch wefannau ar agor mewn tab (hyd yn oed pan yn ailgychwyn).
+
+## These messages are steps on how to use the feature and are shown together.
+
+cfr-doorhanger-pintab-step1 = <b>Clic de</ b> ar y tab rydych am ei binio.
+cfr-doorhanger-pintab-step2 = Dewis <b>Pinio Tab</ b> o'r ddewislen.
+cfr-doorhanger-pintab-step3 = Os fydd gan y wefan ddiweddariad, gwelwch ddot glas ar eich tab wedi'i binio.
+cfr-doorhanger-pintab-animation-pause = Oedi
+cfr-doorhanger-pintab-animation-resume = Ailgychwyn
+
+## Firefox Accounts Message
+
+cfr-doorhanger-bookmark-fxa-header = Cydweddu eich nodau tudalen ym mhob man
+cfr-doorhanger-bookmark-fxa-body = Mae hwn yn dda! Peidiwch bod heb y nod tudalen hon ar eich dyfeisiau symudol. Dechrau arni gyda { -fxaccount-brand-name }.
+cfr-doorhanger-bookmark-fxa-link-text = Cydweddu nodau tudalen nawr…
+cfr-doorhanger-bookmark-fxa-close-btn-tooltip =
+    .aria-label = Cau botwm
+    .title = Cau
+
+## Protections panel
+
+cfr-protections-panel-header = Pori heb gael eich dilyn
+cfr-protections-panel-body = Cadwch eich data i chi'ch hun. Mae { -brand-short-name } yn eich diogelu rhag llawer o'r tracwyr mwyaf cyffredin sy'n eich dilyn ar-lein.
+cfr-protections-panel-link-text = Dysgu rhagor
+
+## What's New toolbar button and panel
+
+# This string is used by screen readers to offer a text based alternative for
+# the notification icon
+cfr-badge-reader-label-newfeature = Nodwedd newydd:
+cfr-whatsnew-button =
+    .label = Beth sy'n Newydd
+    .tooltiptext = Beth sy'n Newydd
+cfr-whatsnew-panel-header = Beth sy'n Newydd
+cfr-whatsnew-release-notes-link-text = Darllenwch y nodiadau rhyddhau
+cfr-whatsnew-fx70-title = Mae { -brand-short-name } nawr yn ymladd yn galetach dros eich preifatrwydd
+cfr-whatsnew-fx70-body =
+    Mae'r diweddariad diweddaraf yn gwella'r nodwedd Diogelu rhag Tracio ac yn ei wneud
+    haws nag erioed i greu cyfrineiriau diogel ar gyfer pob gwefan.
+cfr-whatsnew-tracking-protect-title = Diogelwch eich hun rhag tracwyr
+cfr-whatsnew-tracking-protect-body =
+    Mae { -brand-short-name } yn rhwystro llawer o dracwyr cymdeithasol a thraws-gwefan cyffredin sy'n 
+    dilyn yr hyn rydych chi'n ei wneud ar-lein.
+cfr-whatsnew-tracking-protect-link-text = Gweld Eich Adroddiad
+# This string is displayed before a large numeral that indicates the total
+# number of tracking elements blocked. Don’t add $blockedCount to your
+# localization, because it would result in the number showing twice.
+cfr-whatsnew-tracking-blocked-title =
+    { $blockedCount ->
+        [zero] Tracwyr wedi'u rhwystro
+        [one] Traciwr wedi'i rwystro
+        [two] Draciwr wedi'u rhwystro
+        [few] Traciwr wedi'u rhwystro
+        [many] Thraciwr wedi'u rhwystro
+       *[other] Traciwr wedi'u rhwystro
+    }
+cfr-whatsnew-tracking-blocked-subtitle = Ers { DATETIME($earliestDate, month: "long", year: "numeric") }
+cfr-whatsnew-tracking-blocked-link-text = Gweld yr Adroddiad
+cfr-whatsnew-lockwise-backup-title = Gwnewch gopi wrth gefn o'ch cyfrineiriau
+cfr-whatsnew-lockwise-backup-body = Nawr cynhyrchwch gyfrineiriau diogel y gallwch gael mynediad atyn nhw lle bynnag fyddwch yn mewngofnodi.
+cfr-whatsnew-lockwise-backup-link-text = Cychwyn creu copïau wrth gefn
+cfr-whatsnew-lockwise-take-title = Ewch â'ch cyfrineiriau gyda chi
+cfr-whatsnew-lockwise-take-body =
+    Mae'r ap symudol { -lockwise-brand-short-name } yn caniatáu i chi gael mynediad diogel i'ch
+    cyfrineiriau wrth gefn o unrhyw le.
+cfr-whatsnew-lockwise-take-link-text = Estyn yr ap
+
+## Search Bar
+
+cfr-whatsnew-searchbar-title = Teipio llai, darganfod mwy gyda'r bar cyfeiriad
+cfr-whatsnew-searchbar-body-topsites = Nawr, dewiswch y bar cyfeiriadau, a bydd blwch yn ehangu gyda dolenni i'ch prif wefannau.
+
+## Search bar
+
+cfr-whatsnew-searchbar-icon-alt-text = Eicon chwyddwydr
+
+## Picture-in-Picture
+
+cfr-whatsnew-pip-header = Gwyliwch fideos wrth i chi bori
+cfr-whatsnew-pip-body = Mae Llun mewn Llun yn gosod fideo i mewn i ffenestr sy'n arnofio, fel y gallwch chi wylio wrth weithio mewn tabiau eraill.
+cfr-whatsnew-pip-cta = Dysgu rhagor
+
+## Permission Prompt
+
+cfr-whatsnew-permission-prompt-header = Llai o lamlenni annifyr
+cfr-whatsnew-permission-prompt-body = Mae { -brand-shorter-name } bellach yn rhwystro gwefannau rhag gofyn yn awtomatig am anfon negeseuon llamlen atoch.
+cfr-whatsnew-permission-prompt-cta = Dysgu rhagor
+
+## Fingerprinter Counter
+
+# This string is displayed before a large numeral that indicates the total
+# number of tracking elements blocked. Don’t add $fingerprinterCount to your
+# localization, because it would result in the number showing twice.
+cfr-whatsnew-fingerprinter-counter-header =
+    { $fingerprinterCount ->
+        [zero] Bysbrintwyr wedi'u rhwystro
+        [one] Bysbrintiwr wedi'i rwystro
+        [two] Bysbrintwyr wedi'u rhwystro
+        [few] Bysbrintwyr wedi'u rhwystro
+        [many] Bysbrintwyr wedi'u rhwystro
+       *[other] Bysbrintwyr wedi'u rhwystro
+    }
+cfr-whatsnew-fingerprinter-counter-body = Mae { -brand-shorter-name } yn rhwystro llawer o fysbrintwyr sy'n casglu manylion am eich dyfais a'ch gweithredoedd yn gyfrinachol i greu proffil hysbysebu ohonoch chi.
+# Message variation when fingerprinters count is less than 10
+cfr-whatsnew-fingerprinter-counter-header-alt = Bysbrintwyr
+cfr-whatsnew-fingerprinter-counter-body-alt = Gall { -brand-shorter-name } rwystro bysbrintwyr sy'n casglu manylion am eich dyfais a'ch gweithredoedd yn gyfrinachol i greu proffil hysbysebu ohonoch chi.
+
+## Bookmark Sync
+
+cfr-doorhanger-sync-bookmarks-header = Defnyddiwch y nod tudalen hwn ar eich ffôn
+cfr-doorhanger-sync-bookmarks-body = Cymerwch eich nodau tudalen, cyfrineiriau, hanes a mwy ym mhob man rydych chi wedi mewngofnodi iddo { -brand-product-name }.
+cfr-doorhanger-sync-bookmarks-ok-button = Troi { -sync-brand-short-name } ymlaen
+    .accesskey = T
+
+## Login Sync
+
+cfr-doorhanger-sync-logins-header = Peidiwch Byth â Cholli Cyfrinair Eto
+cfr-doorhanger-sync-logins-body = Cadwch a chydweddu eich cyfrineiriau yn ddiogel i'ch holl ddyfeisiau.
+cfr-doorhanger-sync-logins-ok-button = Agor { -sync-brand-short-name }
+    .accesskey = A
+
+## Send Tab
+
+cfr-doorhanger-send-tab-header = Darllen hwn wrth fynd
+cfr-doorhanger-send-tab-recipe-header = Ewch â'r rysáit hon i'r gegin
+cfr-doorhanger-send-tab-body = Mae'r Tab Anfon yn caniatáu i chi rannu'r ddolen hon yn hawdd i'ch ffôn neu unrhyw le rydych chi wedi mewngofnodi i { -brand-product-name }.
+cfr-doorhanger-send-tab-ok-button = Rhowch gynnig ar y Tab Anfon
+    .accesskey = R
+
+## Firefox Send
+
+cfr-doorhanger-firefox-send-header = Rhannwch y PDF hwn yn ddiogel
+cfr-doorhanger-firefox-send-body = Cadwch eich dogfennau sensitif yn ddiogel rhag llygaid busneslyd gydag amgryptio o'r dechrau i'r diwedd a dolen sy'n diflannu pan fyddwch chi wedi gorffen.
+cfr-doorhanger-firefox-send-ok-button = Rhowch gynnig ar { -send-brand-name }
+    .accesskey = R
+
+## Social Tracking Protection
+
+cfr-doorhanger-socialtracking-ok-button = Gweld y Diogelwch
+    .accesskey = D
+cfr-doorhanger-socialtracking-close-button = Cau
+    .accesskey = C
+cfr-doorhanger-socialtracking-dont-show-again = Peidiwch â dangos negeseuon fel hyn i mi eto
+    .accesskey = d
+cfr-doorhanger-socialtracking-heading = Mae { -brand-short-name } wedi atal rhwydwaith cymdeithasol rhag eich tracio chi yma
+cfr-doorhanger-socialtracking-description = Mae eich preifatrwydd yn bwysig. Mae { -brand-short-name } nawr yn rhwystro tracwyr cyfryngau cymdeithasol cyffredin, gan gyfyngu ar faint o ddata y mae nhw'n gallu ei gasglu am yr hyn rydych chi'n ei wneud ar-lein.
+cfr-doorhanger-fingerprinters-heading = Fe wnaeth { -brand-short-name } rwystro bys brintiwr ar y dudalen hon
+cfr-doorhanger-fingerprinters-description = Mae eich preifatrwydd yn bwysig. Mae { -brand-short-name } nawr yn rhwystro bysbrintwyr, sy'n casglu manylion unigryw y mae modd eu hadnabod am eich dyfais i'ch tracio.
+cfr-doorhanger-cryptominers-heading = Fe wnaeth { -brand-short-name } rwystro cryptogloddwyr ar y dudalen hon
+cfr-doorhanger-cryptominers-description = Mae eich preifatrwydd yn bwysig. Mae { -brand-short-name } nawr yn rhwystro cryptogloddwyr, sy'n defnyddio pŵer cyfrifiadurol eich system i gloddio arian digidol.
+
+## Enhanced Tracking Protection Milestones
+
+# Variables:
+#   $blockedCount (Number) - The total count of blocked trackers. This number will always be greater than 1.
+#   $date (Number) - The date we began recording the count of blocked trackers
+cfr-doorhanger-milestone-heading =
+    { $blockedCount ->
+        [zero] Nid yw { -brand-short-name } wedi rhwystro <b>{ $blockedCount }</b> traciwr ers { $date }!
+        [one] Mae { -brand-short-name } wedi rhwystro <b>{ $blockedCount }</b> traciwr ers { $date }!
+        [two] Mae { -brand-short-name } wedi rhwystro <b>{ $blockedCount }</b> traciwr ers { $date }!
+        [few] Mae { -brand-short-name } wedi rhwystro <b>{ $blockedCount }</b> traciwr ers { $date }!
+        [many] Mae { -brand-short-name } wedi rhwystro dros <b>{ $blockedCount }</b> traciwr ers { $date }!
+       *[other] Mae { -brand-short-name } wedi rhwystro <b>{ $blockedCount }</b> traciwr ers { $date }!
+    }
+cfr-doorhanger-milestone-heading2 =
+    { $blockedCount ->
+        [zero] Mae { -brand-short-name } wedi rhwystro mwy na <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+        [one] Mae { -brand-short-name } wedi rhwystro mwy nag <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+        [two] Mae { -brand-short-name } wedi rhwystro mwy na <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+        [few] Mae { -brand-short-name } wedi rhwystro mwy na <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+        [many] Mae { -brand-short-name } wedi rhwystro mwy na <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+       *[other] Mae { -brand-short-name } wedi rhwystro mwy na <b>{ $blockedCount }</b> o dracwyr ers { DATETIME($date, month: "long", year: "numeric") }!
+    }
+cfr-doorhanger-milestone-ok-button = Gweld y Cyfan
+    .accesskey = G
+cfr-doorhanger-milestone-close-button = Cau
+    .accesskey = C
+
+## What’s New Panel Content for Firefox 76
+
+
+## Lockwise message
+
+cfr-whatsnew-lockwise-header = Crëwch gyfrineiriau diogel yn hawdd
+cfr-whatsnew-lockwise-body = Mae'n anodd meddwl am gyfrineiriau unigryw, diogel ar gyfer pob cyfrif. Wrth greu cyfrinair, dewiswch y maes cyfrinair i ddefnyddio cyfrinair diogel wedi'i gynhyrchu gan { -brand-shorter-name }.
+cfr-whatsnew-lockwise-icon-alt = Eicon { -lockwise-brand-short-name }
+
+## Vulnerable Passwords message
+
+cfr-whatsnew-passwords-header = Derbyn rhybuddion am gyfrineiriau bregus
+cfr-whatsnew-passwords-body = Mae hacwyr yn gwybod bod pobl yn ailddefnyddio'r un cyfrineiriau. Os gwnaethoch chi ddefnyddio'r un cyfrinair ar sawl gwefan, a bod un o'r gwefannau hynny wedi bod yn rhan o dor-data, fe welwch rybudd yn { -lockwise-brand-short-name } i newid eich cyfrinair ar y gwefannau hynny.
+cfr-whatsnew-passwords-icon-alt = Eicon allwedd cyfrinair bregus
+
+## Picture-in-Picture fullscreen message
+
+cfr-whatsnew-pip-fullscreen-header = Cymerwch llun-mewn-llun sgrin lawn
+cfr-whatsnew-pip-fullscreen-body = Pan fyddwch yn gosod fideo i mewn i ffenestr sy'n arnofio, gallwch nawr glicio ddwywaith ar y ffenestr honno i droi'n sgrin lawn.
+cfr-whatsnew-pip-fullscreen-icon-alt = Eicon llun mewn llun
+
+## Protections Dashboard message
+
+cfr-whatsnew-protections-header = Cipolwg ar ddiogelwch
+cfr-whatsnew-protections-body = Mae'r Bwrdd Gwaith Diogelwch yn cynnwys adroddiadau cryno am dor-data a rheoli cyfrineiriau. Nawr gallwch chi olrhain faint o dor-data rydych chi wedi'u datrys, a gweld a allai unrhyw un o'ch cyfrineiriau sydd wedi'u cadw fod wedi bod yn agored i dor-data.
+cfr-whatsnew-protections-cta-link = Gweld y Bwrdd Gwaith Diogelwch
+cfr-whatsnew-protections-icon-alt = Eicon tarian
+
+## Better PDF message
+
+cfr-whatsnew-better-pdf-header = Gwell profiad PDF
+cfr-whatsnew-better-pdf-body = Mae dogfennau PDF nawr yn agor yn uniongyrchol yn { -brand-short-name }, gan gadw'ch llif gwaith o fewn cyrraedd.
+
+## DOH Message
+
+cfr-doorhanger-doh-body = Mae eich preifatrwydd yn bwysig. Mae { -brand-short-name } bellach yn cyfeirio eich ceisiadau DNS yn ddiogel pryd bynnag y bo modd at wasanaeth partner i'ch diogelu wrth i chi bori.
+cfr-doorhanger-doh-header = Chwilio DNS mwy diogel, wedi'u hamgryptio
+cfr-doorhanger-doh-primary-button = Iawn, Wedi deall!
+    .accesskey = I
+cfr-doorhanger-doh-secondary-button = Analluogi
+    .accesskey = A
+
+## Fission Experiment Message
+
+cfr-doorhanger-fission-body-approved = Mae eich preifatrwydd yn bwysig. Erbyn hyn mae { -brand-short-name } yn ynysu, neu'n creu blychau tywod er mwyn cadw gwefannau oddi wrth ei gilydd, sy'n ei gwneud hi'n anoddach i hacwyr ddwyn cyfrineiriau, rhifau cardiau credyd, a manylion sensitif arall, oddi arnoch.
+cfr-doorhanger-fission-header = Ynysu Gwefan
+cfr-doorhanger-fission-primary-button = Iawn, Wedi deall!
+    .accesskey = I
+cfr-doorhanger-fission-secondary-button = Dysgu rhagor
+    .accesskey = D
+
+## What's new: Cookies message
+
+cfr-whatsnew-clear-cookies-header = Diogelwch awtomatig rhag tactegau tracio slei
+cfr-whatsnew-clear-cookies-body = Mae rhai tracwyr yn eich ailgyfeirio i wefannau eraill sy'n gosod cwcis yn gyfrinachol. Mae { -brand-short-name } bellach yn clirio'r cwcis hynny yn awtomatig fel nad oes modd eich dilyn.
+cfr-whatsnew-clear-cookies-image-alt = Llun wedi'i rwystro gan gwci
+
+## What's new: Media controls message
+
+cfr-whatsnew-media-keys-header = Rhagor o reoli cyfryngau
+cfr-whatsnew-media-keys-body = Chwarae ac oedi sain neu fideo yn syth o'ch bysellfwrdd neu'ch clustffon, gan ei gwneud hi'n hawdd rheoli cyfryngau o dab, rhaglen arall, neu hyd yn oed pan fydd eich cyfrifiadur wedi'i gloi. Gallwch hefyd symud rhwng traciau gan ddefnyddio'r bysellau ymlaen ac yn ôl.
+cfr-whatsnew-media-keys-button = Dysgu sut
+
+## What's new: Search shortcuts
+
+cfr-whatsnew-search-shortcuts-header = Llwybrau byr chwilio yn y bar cyfeiriadau
+cfr-whatsnew-search-shortcuts-body = Nawr, pan fyddwch yn teipio manylion gwefan neu beiriant chwilio penodol yn y bar cyfeiriad, bydd llwybr byr glas yn ymddangos yn yr awgrymiadau chwilio isod. Dewiswch y llwybr byr hwnnw i gwblhau eich chwilio'n uniongyrchol o'r bar cyfeiriad.
+
+## What's new: Cookies protection
+
+cfr-whatsnew-supercookies-header = Diogelwch rhag archcwcis maleisus
+cfr-whatsnew-supercookies-body = Gall gwefannau atodi “archcwci” yn gyfrinachol i'ch porwr a all eich dilyn o amgylch y we, hyd yn oed ar ôl i chi glirio'ch cwcis. Mae { -brand-short-name } bellach yn darparu amddiffyniad cryf yn erbyn archcwcis fel nad oes modd eu defnyddio i dracio'ch gweithgareddau ar-lein o un gwefan i'r llall.
+
+## What's new: Better bookmarking
+
+cfr-whatsnew-bookmarking-header = Nodi tudalen gwell
+cfr-whatsnew-bookmarking-body = Mae'n haws cadw golwg ar eich hoff wefannau. Mae { -brand-short-name } bellach yn cofio'ch hoff leoliad ar gyfer nodau tudalen wedi'u cadw, yn dangos y bar offer nodau tudalen yn ragosodedig ar dabiau newydd, ac yn rhoi mynediad hawdd i weddill eich nodau tudalen trwy ffolder bar offer.
+
+## What's new: Cross-site cookie tracking
+
+cfr-whatsnew-cross-site-tracking-header = Diogelwch gynhwysfawr rhag tracio gan gwcis ar draws gwefannau
+cfr-whatsnew-cross-site-tracking-body = Nawr gallwch chi ddewis diogelwch gwell rhag tracio gan gwcis. Gall { -brand-short-name } ynysu eich gweithgareddau a'ch data i'r wefan rydych chi arni ar hyn o bryd felly nid yw gwybodaeth sy'n cael ei storio yn y porwr yn cael ei rhannu rhwng gwefannau.
diff --git a/l10n-cy/browser/browser/newtab/newtab.ftl b/l10n-cy/browser/browser/newtab/newtab.ftl
new file mode 100644
index 0000000000..0001327590
--- /dev/null
+++ b/l10n-cy/browser/browser/newtab/newtab.ftl
@@ -0,0 +1,247 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### Firefox Home / New Tab strings for about:home / about:newtab.
+
+newtab-page-title = Tab Newydd
+newtab-settings-button =
+    .title = Cyfaddasu eich tudalen Tab Newydd
+newtab-personalize-button-label = Personoli
+    .title = Personoli tab newydd
+    .aria-label = Personoli tab newydd
+
+## Search box component.
+
+# "Search" is a verb/action
+newtab-search-box-search-button =
+    .title = Chwilio
+    .aria-label = Chwilio
+newtab-search-box-search-the-web-text = Chwilio'r We
+newtab-search-box-search-the-web-input =
+    .placeholder = Chwilio'r We
+    .title = Chwilio'r We
+    .aria-label = Chwilio'r We
+newtab-search-box-text = Chwilio'r we
+newtab-search-box-input =
+    .placeholder = Chwilio'r we
+    .aria-label = Chwilio'r we
+
+## Top Sites - General form dialog.
+
+newtab-topsites-add-search-engine-header = Ychwanegu Peiriant Chwilio
+newtab-topsites-add-topsites-header = Hoff Wefan Newydd
+newtab-topsites-add-shortcut-header = Llwybr Byr Newydd
+newtab-topsites-edit-topsites-header = Golygu'r Hoff Wefan
+newtab-topsites-edit-shortcut-header = Golygu Llwybr Byr
+newtab-topsites-title-label = Teitl
+newtab-topsites-title-input =
+    .placeholder = Rhoi teitl
+newtab-topsites-url-label = URL
+newtab-topsites-url-input =
+    .placeholder = Teipio neu ludo URL
+newtab-topsites-url-validation = Mae angen URL Ddilys
+newtab-topsites-image-url-label = URL Delwedd Gyfaddas
+newtab-topsites-use-image-link = Defnyddio delwedd gyfaddas…
+newtab-topsites-image-validation = Methodd y ddelwedd â llwytho. Defnyddiwch URL gwahanol.
+
+## Top Sites - General form dialog buttons. These are verbs/actions.
+
+newtab-topsites-cancel-button = Diddymu
+newtab-topsites-delete-history-button = Dileu o'r Hanes
+newtab-topsites-save-button = Cadw
+newtab-topsites-preview-button = Rhagolwg
+newtab-topsites-add-button = Ychwanegu
+
+## Top Sites - Delete history confirmation dialog.
+
+newtab-confirm-delete-history-p1 = Ydych chi'n siŵr eich bod chi am ddileu pob enghraifft o'r dudalen hon o'ch hanes?
+# "This action" refers to deleting a page from history.
+newtab-confirm-delete-history-p2 = Nid oes modd dadwneud hyn.
+
+## Top Sites - Sponsored label
+
+newtab-topsite-sponsored = Noddwyd
+
+## Context Menu - Action Tooltips.
+
+# General tooltip for context menus.
+newtab-menu-section-tooltip =
+    .title = Agor y ddewislen
+    .aria-label = Agor y ddewislen
+# Tooltip for dismiss button
+newtab-dismiss-button-tooltip =
+    .title = Tynnu
+    .aria-label = Tynnu
+# This tooltip is for the context menu of Pocket cards or Topsites
+# Variables:
+#  $title (String): The label or hostname of the site. This is for screen readers when the context menu button is focused/active.
+newtab-menu-content-tooltip =
+    .title = Agor y ddewislen
+    .aria-label = Agor dewislen cynnwys { $title }
+# Tooltip on an empty topsite box to open the New Top Site dialog.
+newtab-menu-topsites-placeholder-tooltip =
+    .title = Golygu'r wefan
+    .aria-label = Golygu'r wefan
+
+## Context Menu: These strings are displayed in a context menu and are meant as a call to action for a given page.
+
+newtab-menu-edit-topsites = Golygu
+newtab-menu-open-new-window = Agor Ffenestr Newydd
+newtab-menu-open-new-private-window = Agor mewn Ffenestr Preifat Newydd
+newtab-menu-dismiss = Cau
+newtab-menu-pin = Pinio
+newtab-menu-unpin = Dad-binio
+newtab-menu-delete-history = Dileu o'r Hanes
+newtab-menu-save-to-pocket = Cadw i { -pocket-brand-name }
+newtab-menu-delete-pocket = Dileu o { -pocket-brand-name }
+newtab-menu-archive-pocket = Archifo i { -pocket-brand-name }
+newtab-menu-show-privacy-info = Ein noddwyr a'ch preifatrwydd
+
+## Message displayed in a modal window to explain privacy and provide context for sponsored content.
+
+newtab-privacy-modal-button-done = Gorffen
+newtab-privacy-modal-button-manage = Rheoli gosodiadau cynnwys wedi'i noddi
+newtab-privacy-modal-header = Mae eich preifatrwydd yn bwysig.
+newtab-privacy-modal-paragraph-2 =
+    Yn ogystal â rhannu straeon cyfareddol, rydyn hefyd yn dangos i chi
+    gynnwys perthnasol wedi'i ddewis yn ofalus gan noddwyr dethol. Peidiwch â phoeni,
+    nid yw eich data pori byth yn gadael eich copi personol o { -brand-product-name } - nid ydym 
+    yn ei weld, na'n
+    noddwyr chwaith.
+newtab-privacy-modal-link = Dysgwch sut mae preifatrwydd yn gweithio ar y tab newydd
+
+##
+
+# Bookmark is a noun in this case, "Remove bookmark".
+newtab-menu-remove-bookmark = Tynnu Nod Tudalen
+# Bookmark is a verb here.
+newtab-menu-bookmark = Nod Tudalen
+
+## Context Menu - Downloaded Menu. "Download" in these cases is not a verb,
+## it is a noun. As in, "Copy the link that belongs to this downloaded item".
+
+newtab-menu-copy-download-link = Copïo Dolen Llwytho i Lawr
+newtab-menu-go-to-download-page = Mynd i'r Dudalen Llwytho i Lawr
+newtab-menu-remove-download = Tynnu o'r Hanes
+
+## Context Menu - Download Menu: These are platform specific strings found in the context menu of an item that has
+## been downloaded. The intention behind "this action" is that it will show where the downloaded file exists on the file
+## system for each operating system.
+
+newtab-menu-show-file =
+    { PLATFORM() ->
+        [macos] Dangos yn Finder
+       *[other] Agor Ffolder Cynhwysol
+    }
+newtab-menu-open-file = Agor Ffeil
+
+## Card Labels: These labels are associated to pages to give
+## context on how the element is related to the user, e.g. type indicates that
+## the page is bookmarked, or is currently open on another device.
+
+newtab-label-visited = Ymwelwyd
+newtab-label-bookmarked = Nod Tudalen
+newtab-label-removed-bookmark = Wedi Tynnu'r Nod Tudalen
+newtab-label-recommended = Trendio
+newtab-label-saved = Wedi ei gadw i { -pocket-brand-name }
+newtab-label-download = Wedi eu Llwytho i Lawr
+# This string is used in the story cards to indicate sponsored content
+# Variables:
+#  $sponsorOrSource (String): This is the name of a company or their domain
+newtab-label-sponsored = Noddir gan { $sponsorOrSource }
+# This string is used at the bottom of story cards to indicate sponsored content
+# Variables:
+#  $sponsor (String): This is the name of a sponsor
+newtab-label-sponsored-by = Noddir gan { $sponsor }
+
+## Section Menu: These strings are displayed in the section context menu and are
+## meant as a call to action for the given section.
+
+newtab-section-menu-remove-section = Tynnu'r Adran
+newtab-section-menu-collapse-section = Cau'r Adran
+newtab-section-menu-expand-section = Estyn yr Adran
+newtab-section-menu-manage-section = Rheoli'r Adran
+newtab-section-menu-manage-webext = Rheoli Estyniad
+newtab-section-menu-add-topsite = Ychwanegu Hoff Wefan
+newtab-section-menu-add-search-engine = Ychwanegu Peiriant Chwilio
+newtab-section-menu-move-up = Symud i Fyny
+newtab-section-menu-move-down = Symud i Lawr
+newtab-section-menu-privacy-notice = Hysbysiad Preifatrwydd
+
+## Section aria-labels
+
+newtab-section-collapse-section-label =
+    .aria-label = Cau'r Adran
+newtab-section-expand-section-label =
+    .aria-label = Ehangu'r Adran
+
+## Section Headers.
+
+newtab-section-header-topsites = Hoff Wefannau
+newtab-section-header-highlights = Goreuon
+newtab-section-header-recent-activity = Gweithgaredd diweddar
+# Variables:
+#  $provider (String): Name of the corresponding content provider.
+newtab-section-header-pocket = Argymhellwyd gan { $provider }
+
+## Empty Section States: These show when there are no more items in a section. Ex. When there are no more Pocket story recommendations, in the space where there would have been stories, this is shown instead.
+
+newtab-empty-section-highlights = Cychwynnwch bori ac fe ddangoswn rhai erthyglau, fideos a thudalennau eraill difyr rydych wedi ymweld â nhw'n ddiweddar neu wedi gosod nod tudalen arnyn nhw yma.
+# Ex. When there are no more Pocket story recommendations, in the space where there would have been stories, this is shown instead.
+# Variables:
+#  $provider (String): Name of the content provider for this section, e.g "Pocket".
+newtab-empty-section-topstories = Rydych wedi dal i fynDewch nôl rhywbryd eto am fwy o'r straeon pwysicaf gan { $provider }. Methu aros? Dewiswch bwnc poblogaidd i ganfod straeon da o ar draws y we.
+
+## Empty Section (Content Discovery Experience). These show when there are no more stories or when some stories fail to load.
+
+newtab-discovery-empty-section-topstories-header = Wedi dal i fyny!
+newtab-discovery-empty-section-topstories-content = Dewch nôl eto am ragor o straeon.
+newtab-discovery-empty-section-topstories-try-again-button = Ceisiwch eto
+newtab-discovery-empty-section-topstories-loading = Llwytho…
+# Displays when a layout in a section took too long to fetch articles.
+newtab-discovery-empty-section-topstories-timed-out = Wps! Bron a lwytho'r adran hon, ond nid yn llwyr.
+
+## Pocket Content Section.
+
+# This is shown at the bottom of the trending stories section and precedes a list of links to popular topics.
+newtab-pocket-read-more = Pynciau Poblogaidd:
+newtab-pocket-more-recommendations = Rhagor o Argymhellion
+newtab-pocket-learn-more = Dysgu rhagor
+newtab-pocket-cta-button = Defnyddio { -pocket-brand-name }
+newtab-pocket-cta-text = Cadw'r straeon rydych yn eu hoffi i { -pocket-brand-name } a bwydo'ch meddwl á deunydd diddorol.
+
+## Error Fallback Content.
+## This message and suggested action link are shown in each section of UI that fails to render.
+
+newtab-error-fallback-info = Wps, aeth rhywbeth o'i le wrth llwytho'r cynnwys hwn.
+newtab-error-fallback-refresh-link = Adnewyddu'r dudalen i geisio eto.
+
+## Customization Menu
+
+newtab-custom-shortcuts-title = Llwybrau Byr
+newtab-custom-shortcuts-subtitle = Gwefannau rydych yn eu cadw neu'n ymweld â nhw
+newtab-custom-row-selector =
+    { $num ->
+        [zero] { $num } rhesi
+        [one] { $num } rhes
+        [two] { $num } res
+        [few] { $num } rhes
+        [many] { $num } rhes
+       *[other] { $num } rhes
+    }
+newtab-custom-sponsored-sites = Llwybrau byr wedi'u noddi
+newtab-custom-pocket-title = Argymhellir gan  { -pocket-brand-name }
+newtab-custom-pocket-subtitle = Cynnwys eithriadol wedi'i guradu gan { -pocket-brand-name }, rhan o deulu { -brand-product-name }
+newtab-custom-pocket-sponsored = Straeon wedi'u noddi
+newtab-custom-recent-title = Gweithgaredd diweddar
+newtab-custom-recent-subtitle = Detholiad o wefannau a chynnwys diweddar
+newtab-custom-close-button = Cau
+# For the "Snippets" feature traditionally on about:home.
+# Alternative translation options: "Small Note" or something that
+# expresses the idea of "a small message, shortened from something else,
+# and non-essential but also not entirely trivial and useless.
+newtab-custom-snippets-title = Pytiau
+newtab-custom-snippets-subtitle = Awgrymiadau a newyddion gan { -vendor-short-name } a { -brand-product-name }
+newtab-custom-settings = Rheoli rhagor o osodiadau
diff --git a/l10n-cy/browser/browser/newtab/onboarding.ftl b/l10n-cy/browser/browser/newtab/onboarding.ftl
new file mode 100644
index 0000000000..c57f6c5e37
--- /dev/null
+++ b/l10n-cy/browser/browser/newtab/onboarding.ftl
@@ -0,0 +1,241 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### UI strings for the simplified onboarding modal / about:welcome
+### Various strings use a non-breaking space to avoid a single dangling /
+### widowed word, so test on various window sizes if you also want this.
+
+
+## These button action text can be split onto multiple lines, so use explicit
+## newlines in translations to control where the line break appears (e.g., to
+## avoid breaking quoted text).
+
+onboarding-button-label-learn-more = Dysgu Rhagor
+onboarding-button-label-get-started = Cychwyn Arni
+
+## Welcome modal dialog strings
+
+
+### UI strings for the simplified onboarding / multistage about:welcome
+### Various strings use a non-breaking space to avoid a single dangling /
+### widowed word, so test on various window sizes if you also want this.
+
+
+## Welcome page strings
+
+onboarding-welcome-header = Croeso i { -brand-short-name }
+onboarding-welcome-body = Mae'r porwr gyda chi. <br/> Dyma weddill { -brand-product-name }.
+onboarding-welcome-learn-more = Dysgu rhagor am y buddiannau.
+onboarding-welcome-modal-get-body = Mae'r porwr gennych. <br/>Nawr, manteisiwch i'r eithaf ar { -brand-product-name }.
+onboarding-welcome-modal-supercharge-body = Cryfhewch eich diogelwch preifatrwydd.
+onboarding-welcome-modal-privacy-body = Mae'r porwr gennych chi. Gadewch i ni ychwanegu mwy o ddiogelwch preifatrwydd.
+onboarding-welcome-modal-family-learn-more = Dysgu am deulu cynnyrch { -brand-product-name }.
+onboarding-welcome-form-header = Cychwynnwch Yma
+onboarding-join-form-body = Rhowch eich cyfeiriad e-bost i ddechrau.
+onboarding-join-form-email =
+    .placeholder = Rhowch e-bost
+onboarding-join-form-email-error = Mae angen e-bost dilys
+onboarding-join-form-legal = Drwy barhau, rydych yn cytuno i'r <a data-l10n-name="terms">>Amodau Gwasanaeth</a> a'r <a data-l10n-name="privacy">Hysbysiad Preifatrwydd</a>.
+onboarding-join-form-continue = Parhau
+# This message is followed by a link using onboarding-join-form-signin ("Sign In") as text.
+onboarding-join-form-signin-label = A oes gennych chi gyfrif yn barod?
+# Text for link to submit the sign in form
+onboarding-join-form-signin = Mewngofnodi
+onboarding-start-browsing-button-label = Cychwyn Pori
+onboarding-not-now-button-label = Nid nawr
+onboarding-cards-dismiss =
+    .title = Cau
+    .aria-label = Cau
+
+## Welcome full page string
+
+onboarding-fullpage-welcome-subheader = Gadewch i ni ddechrau edrych ar bopeth y gallwch ei wneud.
+onboarding-fullpage-form-email =
+    .placeholder = Eich cyfeiriad e-bost…
+
+## Firefox Sync modal dialog strings.
+
+onboarding-sync-welcome-header = Mynd â { -brand-product-name } gyda Chi
+onboarding-sync-welcome-content = Cael eich nodau tudalen, hanes, cyfrineiriau a gosodiadau eraill ar eich holl ddyfeisiau.
+onboarding-sync-welcome-learn-more-link = Dysgu rhagor am Gyfrif Firefox
+onboarding-sync-form-input =
+    .placeholder = E-bost
+onboarding-sync-form-continue-button = Parhau
+onboarding-sync-form-skip-login-button = Hepgor y cam hwn
+
+## This is part of the line "Enter your email to continue to Firefox Sync"
+
+onboarding-sync-form-header = Rhowch eich e-bost
+onboarding-sync-form-sub-header = ac ymlaen i { -sync-brand-name }
+
+## These are individual benefit messages shown with an image, title and
+## description.
+
+onboarding-benefit-products-text = Gwnewch bethau gyda chasgliad o offer sy'n parchu eich preifatrwydd ar draws eich dyfeisiau.
+# "Personal Data Promise" is a concept that should be translated consistently
+# across the product. It refers to a concept shown elsewhere to the user: "The
+# Firefox Personal Data Promise is the way we honor your data in everything we
+# make and do. We take less data. We keep it safe. And we make sure that we are
+# transparent about how we use it."
+onboarding-benefit-privacy-text = Mae popeth rydym yn ei wneud yn cadw at ein Addewid ar Ddata Personol: Cymrwch lai. Cadwch ef yn ddiogel. Dim cyfrinachau.
+onboarding-benefit-sync-title = { -sync-brand-short-name }
+onboarding-benefit-sync-text = Cymerwch eich nodau tudalen, cyfrineiriau, hanes, a mwy ym mhobman rydych chi'n defnyddio { -brand-product-name }.
+onboarding-benefit-monitor-title = { -monitor-brand-short-name }
+onboarding-benefit-monitor-text = Cewch eich hysbysu pan fydd eich manylion personol mewn tor-data hysbys.
+onboarding-benefit-lockwise-title = { -lockwise-brand-short-name }
+onboarding-benefit-lockwise-text = Rheoli cyfrineiriau sy'n ddiogel ac yn gludadwy.
+
+## Custom Return To AMO onboarding strings
+
+return-to-amo-subtitle = Gwych, mae { -brand-short-name } gennych
+# <img data-l10n-name="icon"/> will be replaced with the icon belonging to the extension
+#
+# Variables:
+#   $addon-name (String) - Name of the add-on
+return-to-amo-addon-title = Nawr gadewch i ni gael <img data-l10n-name="icon"/> <b>{ $addon-name }</b> i chi.
+return-to-amo-add-extension-label = Ychwanegwch yr Estyniad
+
+## Multistage 3-screen onboarding flow strings (about:welcome pages)
+
+# The <span data-l10n-name="zap"></span> in this string allows a "zap" underline style to be
+# automatically added to the text inside it. { -brand-short-name } should stay inside the span.
+onboarding-multistage-welcome-header = Croeso i <span data-l10n-name="zap">{ -brand-short-name }</span>
+onboarding-multistage-welcome-subtitle = Y porwr cyflym, diogel a phreifat sydd â chefnogaeth corff dim-er-elw.
+onboarding-multistage-welcome-primary-button-label = Cychwyn Gosod
+onboarding-multistage-welcome-secondary-button-label = Mewngofnodi
+onboarding-multistage-welcome-secondary-button-text = Oes gennych chi gyfrif?
+# The <span data-l10n-name="zap"></span> in this string allows a "zap" underline style to be
+# automatically added to the text inside it. "more" should stay inside the span.
+onboarding-multistage-import-header = Mewnforiwch eich cyfrineiriau, nodau tudalen, a <span data-l10n-name="zap">mwy</span>
+onboarding-multistage-import-subtitle = Yn dod o borwr arall? Mae'n hawdd dod â phopeth gyda chi  i { -brand-short-name }.
+onboarding-multistage-import-primary-button-label = Cychwyn Mewnforio
+onboarding-multistage-import-secondary-button-label = Nid nawr
+# Info displayed in the footer of import settings screen during onboarding flow.
+# This supports welcome screen showing top sites imported from the user's default browser.
+onboarding-import-sites-disclaimer = Cafwyd hyd i'r gwefannau hyn ar y ddyfais hon. Nid yw { -brand-short-name } yn cadw nac yn cydweddu data o borwr arall oni bai eich bod yn dewis ei fewnforio.
+# Aria-label to make the "steps" of multistage onboarding visible to screen readers.
+# Variables:
+#   $current (Int) - Number of the current page
+#   $total (Int) - Total number of pages
+onboarding-welcome-steps-indicator =
+    .aria-label = Cychwyn arni: sgrin { $current } o { $total }
+# The <span data-l10n-name="zap"></span> in this string allows a "zap" underline style to be
+# automatically added to the text inside it. "look" should stay inside the span.
+onboarding-multistage-theme-header = Dewiswch <span data-l10n-name = "zap">olwg</span>
+onboarding-multistage-theme-subtitle = Personoli { -brand-short-name } gyda thema.
+onboarding-multistage-theme-primary-button-label = Cadw Thema
+onboarding-multistage-theme-secondary-button-label = Nid nawr
+# Automatic theme uses operating system color settings
+onboarding-multistage-theme-label-automatic = Awtomatig
+onboarding-multistage-theme-label-light = Golau
+onboarding-multistage-theme-label-dark = Tywyll
+# "Firefox Alpenglow" here is the name of the theme, and should be kept in English.
+onboarding-multistage-theme-label-alpenglow = Firefox Alpenglow
+
+## Please make sure to split the content of the title attribute into lines whose
+## width corresponds to about 40 Latin characters, to ensure that the tooltip
+## doesn't become too long. Line breaks will be preserved when displaying the
+## tooltip.
+
+# Tooltip displayed on hover of automatic theme
+onboarding-multistage-theme-tooltip-automatic-2 =
+    .title =
+        Dilyn gwedd eich system weithredu
+        ar gyfer botymau, dewislenni a ffenestri.
+# Input description for automatic theme
+onboarding-multistage-theme-description-automatic-2 =
+    .aria-description =
+        Dilyn gwedd eich system weithredu
+        ar gyfer botymau, dewislenni a ffenestri.
+# Tooltip displayed on hover of light theme
+onboarding-multistage-theme-tooltip-light-2 =
+    .title =
+        Defnyddio gwedd olau ar gyfer botymau,
+        dewislenni, a ffenestri.
+# Input description for light theme
+onboarding-multistage-theme-description-light =
+    .aria-description =
+        Defnyddio gwedd olau ar gyfer botymau,
+        dewislenni, a ffenestri.
+# Tooltip displayed on hover of dark theme
+onboarding-multistage-theme-tooltip-dark-2 =
+    .title =
+        Defnyddio gwedd dywyll ar gyfer botymau,
+        dewislenni, a ffenestri.
+# Input description for dark theme
+onboarding-multistage-theme-description-dark =
+    .aria-description =
+        Defnyddio gwedd dywyll ar gyfer botymau,
+        dewislenni, a ffenestri.
+# Tooltip displayed on hover of Alpenglow theme
+onboarding-multistage-theme-tooltip-alpenglow-2 =
+    .title =
+        Defnyddio gwedd liwgar ar gyfer botymau,
+        dewislenni, a ffenestri.
+# Input description for Alpenglow theme
+onboarding-multistage-theme-description-alpenglow =
+    .aria-description =
+        Defnyddio gwedd liwgar ar gyfer botymau,
+        dewislenni, a ffenestri.
+
+## These strings belong to the individual onboarding messages.
+
+
+## Each message has a title and a description of what the browser feature is.
+## Each message also has an associated button for the user to try the feature.
+## The string for the button is found above, in the UI strings section
+
+onboarding-tracking-protection-title2 = Diogelu Rhag Tracio
+onboarding-tracking-protection-text2 = Mae { -brand-short-name } yn helpu i atal gwefannau rhag eich tracio ar-lein, gan ei gwneud yn anos i hysbysebion eich dilyn o gwmpas y we.
+onboarding-tracking-protection-button2 = Sut mae'n Gweithio
+onboarding-data-sync-title = Mynd â'ch Gosodiadau gyda Chi
+# "Sync" is short for synchronize.
+onboarding-data-sync-text2 = Cydweddwch eich nodau tudalen, cyfrineiriau, a mwy ym mhob man y byddwch yn defnyddio { -brand-product-name }.
+onboarding-data-sync-button2 = Mewngofnodwch i { -sync-brand-short-name }
+onboarding-firefox-monitor-title = Cadw'n effro i achosion o dor-data
+onboarding-firefox-monitor-text2 = Mae { -monitor-brand-name } yn monitro os yw eich e-bost wedi ymddangos mewn tor-data ac yn eich rhybuddio os yw'n ymddangos mewn tor-data newydd.
+onboarding-firefox-monitor-button = Cofrestru am Rhybuddion
+onboarding-browse-privately-title = Pori'n Breifat
+onboarding-browse-privately-text = Mae Pori Preifat yn clirio'ch hanes chwilio a phori er mwyn ei gadw'n gyfrinachol rhag unrhyw un sy'n defnyddio'ch cyfrifiadur.
+onboarding-browse-privately-button = Agor Ffenestr Breifat
+onboarding-firefox-send-title = Cadw eich Ffeiliau a Rennir yn breifat
+onboarding-firefox-send-text2 = Llwythwch eich ffeiliau i fyny i { -send-brand-name } i'w rhannu gydag amgryptio o'r dechrau i'r diwedd a dolen sy'n dod i ben yn awtomatig.
+onboarding-firefox-send-button = Rhoi cynnig ar { -send-brand-name }
+onboarding-mobile-phone-title = Rhoi { -brand-product-name } ar Eich Ffôn
+onboarding-mobile-phone-text = Llwythwch { -brand-product-name } i lawr ar gyfer iOS neu Android a chydweddu eich data ar draws dyfeisiau.
+# "Mobile" is short for mobile/cellular phone, "Browser" is short for web
+# browser.
+onboarding-mobile-phone-button = Llwytho Porwr Symudol i lawr
+onboarding-send-tabs-title = Anfon Tabiau Atoch Chi eich Hun
+# "Send Tabs" refers to "Send Tab to Device" feature that appears when opening a
+# tab's context menu.
+onboarding-send-tabs-text2 = Rhannu tudalennau'n hawdd rhwng eich dyfeisiau heb orfod copïo dolenni na gadael y porwr.
+onboarding-send-tabs-button = Cychwyn Defnyddio Anfon Tabiau
+onboarding-pocket-anywhere-title = Darllen a Gwrando yn Unrhyw Le
+onboarding-pocket-anywhere-text2 = Cadwch eich hoff gynnwys all-lein gyda'r Ap { -pocket-brand-name } a darllenwch, gwrandewch, a gwyliwch pryd bynnag y mae'n gyfleus i chi.
+onboarding-pocket-anywhere-button = Rhoi cynnig ar { -pocket-brand-name }
+onboarding-lockwise-strong-passwords-title = Creu a Chadw Cyfrineiriau Cryf
+onboarding-lockwise-strong-passwords-text = Mae { -lockwise-brand-name } yn creu cyfrineiriau cryf yn y fan a'r lle ac yn cadw pob un ohonyn nhw mewn un man.
+onboarding-lockwise-strong-passwords-button = Rheoli'ch Mewngofnodi
+onboarding-facebook-container-title = Gosod Ffiniau i Facebook
+onboarding-facebook-container-text2 = Mae { -facebook-container-brand-name } yn cadw eich proffil ar wahân i bopeth arall, gan ei gwneud yn anos i Facebook eich targedu chi gyda hysbysebion.
+onboarding-facebook-container-button = Ychwanegu'r Estyniad
+onboarding-import-browser-settings-title = Mewnforio Eich Nodau Tudalen, Cyfrineiriau, a Mwy
+onboarding-import-browser-settings-text = Symud yn sydyn - mae'n hawdd dod â'ch gwefannau a'ch gosodiadau Chrome gyda chi.
+onboarding-import-browser-settings-button = Mewnforio Data Chrome
+onboarding-personal-data-promise-title = Preifat o Fwriad
+onboarding-personal-data-promise-text = Mae { -brand-product-name } yn trin eich data â pharch trwy gymryd llai ohono, ei ddiogelu a bod yn glir ynglŷn â sut rydyn ni'n ei ddefnyddio.
+onboarding-personal-data-promise-button = Darllenwch ein Addewid
+
+## Message strings belonging to the Return to AMO flow
+
+return-to-amo-sub-header = Gwych, mae gennych { -brand-short-name }
+# <icon></icon> will be replaced with the icon belonging to the extension
+#
+# Variables:
+#   $addon-name (String) - Name of the add-on
+return-to-amo-addon-header = Nawr gadewch i ni gael <icon> </icon> <b> { $addon-name } </ B> i chi.
+return-to-amo-extension-button = Ychwanegu'r Estyniad
+return-to-amo-get-started-button = Cychwyn gyda { -brand-short-name }
diff --git a/l10n-cy/browser/browser/nsserrors.ftl b/l10n-cy/browser/browser/nsserrors.ftl
new file mode 100644
index 0000000000..f27480e0c4
--- /dev/null
+++ b/l10n-cy/browser/browser/nsserrors.ftl
@@ -0,0 +1,354 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# DO NOT ADD THINGS OTHER THAN ERROR MESSAGES HERE.
+# This file gets parsed into a JS dictionary of all known error message ids in
+# gen_aboutneterror_codes.py . If we end up needing fluent attributes or
+# refactoring them in some way, the script will need updating.
+
+# Variables:
+# $hostname (String) - Hostname of the website with SSL error.
+# $errorMessage (String) - Error message corresponding to the type of error we are experiencing.
+ssl-connection-error = Digwyddodd gwall wrth gysylltu â { $hostname }. { $errorMessage }
+
+# Variables:
+# $error (string) - NSS error code string that specifies type of cert error. e.g. unknown issuer, invalid cert, etc.
+cert-error-code-prefix = Cod gwall: { $error }
+
+psmerr-ssl-disabled = Methu cysylltu'n ddiogel oherwydd bod y protocol SSL wedi ei analluogi.
+psmerr-ssl2-disabled = Methu cysylltu'n ddiogel oherwydd bod y wefan'n defnyddio hen fersiwn anniogel o brotocol SSL.
+
+# This is a multi-line message.
+psmerr-hostreusedissuerandserial =
+    Rydych wedi derbyn tystysgrif annilys.  Cysylltwch gweinyddwr y gweinydd neu gyfathrebwr e-bost a rhannu'r wybodaeth ganlynol:
+    
+    Mae eich tystysgrif yn cynnwys yr un rhifau cyfresol a thystysgrif arall wedi ei gyhoeddi gan yr awdurdod tystysgrifau.  Defnyddiwch dystysgrif newydd yn cynnwys rhif cyfresol unigryw.
+
+ssl-error-export-only-server = Methu cyfathrebu'n ddiogel. Nid yw'r cyfoed cyn cynnal amgryptiad lefel uchel.
+ssl-error-us-only-server = Methu cyfathrebu'n ddiogel. Mae'r cyfoed angen amgryptiad lefel uchel nad yw'n cael ei gynnal.
+ssl-error-no-cypher-overlap = Methu cyfathrebu'n ddiogel gyda cyfoed: dim algorithm(au) amgrypriad cyffredin.
+ssl-error-no-certificate = Methu canfod tystysgrif neu allwedd angenrheidiol ar gyfer dilysu.
+ssl-error-bad-certificate = Methu cyfathrebu'n ddiogel gyda'r cyfoed: tystysgrif y cyfoed wedi ei wrthod.
+ssl-error-bad-client = Mae'r gweinydd wedi derbyn data gwael gan y cleient.
+ssl-error-bad-server = Mae'r cleient wedi derbyn data gwael gan y gweinydd.
+ssl-error-unsupported-certificate-type = Maeth o dystysgrif sydd heb ei gynnal.
+ssl-error-unsupported-version = Mae'r cyfoed yn defnyddio math o brotocol diogel nad yw'n cael ei gynnal.
+ssl-error-wrong-certificate = Methodd dilysu'r cleient: nid yw allwedd breifat yng nghronfa ddata allweddi yn cydfynd â'r allwedd gyhoeddus yng gntonfa ddata'r tystysgrifau.
+ssl-error-bad-cert-domain = Methu cyfathrebu'n ddiogel gyda'r cyfoed; nid yw'r enw parth yn cydfynd â thystysgrif y gweinydd.
+ssl-error-post-warning = Cod gwall SSL heb ei adnabod.
+ssl-error-ssl2-disabled = Dim ond SSL fersiwn 2 mae'r cyfoed yn ei gynnal ac mae wedi ei analluogi'n lleol.
+ssl-error-bad-mac-read = Derbyniodd SSL gofnod gyda Chod Dilysu Neges anghywir.
+ssl-error-bad-mac-alert = Mae cyfoed SSL yn cofnodi Cod Dilysu Neges anghywir.
+ssl-error-bad-cert-alert = Nid yw cyfode SSL: yn gallu dilysu eich tystysgrif.
+ssl-error-revoked-cert-alert = Mae'r cyfoed SSL wedi gwrthod eich tystysgrif fel un wedi ei atal.
+ssl-error-expired-cert-alert = Mae'r cyfoed SSL wedi gwrthod eich tystysgrif fel un wedi dod i ben.
+ssl-error-ssl-disabled = Methu cysylltu: SSL wedi ei analluogi.
+ssl-error-fortezza-pqg = Methu cysylltu: cyfoed SSL mewn parth FORTEZZA arall.
+ssl-error-unknown-cipher-suite = Mae cais wedi ei dderbyn am swit seiffr SSL.
+ssl-error-no-ciphers-supported = Nid oes swit seiffr ar gael ac wedi eu galluogi yn y rhaglen hon.
+ssl-error-bad-block-padding = Mae SSL wedi derbyn cofnod gyda phadin bloc gwael.
+ssl-error-rx-record-too-long = Mae SSL wedi derbyn cofnod sy'n hirach na'r hyd posib.
+ssl-error-tx-record-too-long = Mae SSL wedi ceisio anfon cofnod sy'n fwy na'r hyd posib.
+ssl-error-rx-malformed-hello-request = Mae SSL wedi derbyn neges ysgwyd llaw Cais Helo anffurf.
+ssl-error-rx-malformed-client-hello = Mae SSL wedi derbyn neges ysgwyd llaw Helo Cleient anffurf.
+ssl-error-rx-malformed-server-hello = Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd anffurf.
+ssl-error-rx-malformed-certificate = Mae SSL wedi derbyn neges ysgwyd llaw Tystysgrif anffurf.
+ssl-error-rx-malformed-server-key-exch = Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Gweinydd anffurf.
+ssl-error-rx-malformed-cert-request = Derbyniodd SSL neges ysgwyd llaw Cais Tystysgrif anffurfedig.
+ssl-error-rx-malformed-hello-done = Derbyniodd SSL neges ysgwyd llaw Server Hello Done anffurfedig.
+ssl-error-rx-malformed-cert-verify = Mae SSL wedi derbyn neges ysgwyd llaw Dilysu Tystysgrif anffurf.
+ssl-error-rx-malformed-client-key-exch = Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Cleient anffurf.
+ssl-error-rx-malformed-finished = Mae SSL wedi derbyn neges ysgwyd llaw Terfynnwyd annfurf.
+ssl-error-rx-malformed-change-cipher = Mae SSL wedi derbyn cofnod Manyleb Seiffr Newid anffurf.
+ssl-error-rx-malformed-alert = Mae SSL wedi derbyn cofnod Rhybudd anffurf.
+ssl-error-rx-malformed-handshake = Mae SSL wedi derbyn cofnod Ysgwyd Llaw anffurf.
+ssl-error-rx-malformed-application-data = Mae SSL wedi derbyn cofnod Data Rhaglen Anffurf.
+ssl-error-rx-unexpected-hello-request = Mae SSL wedi derbyn neges ysgwyd llaw Cais Helo annisgwyl.
+ssl-error-rx-unexpected-client-hello = Mae SSL wedi derbyn neges ysgwyd llaw Helo Cleient annisgwyl.
+ssl-error-rx-unexpected-server-hello = Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd annisgwyl.
+ssl-error-rx-unexpected-certificate = Mae SSL wedi derbyn neges ysgwyd llaw Tystysgrif annisgwyl.
+ssl-error-rx-unexpected-server-key-exch = Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Gweinydd annisgwyl.
+ssl-error-rx-unexpected-cert-request = Mae SSL wedi derbyn neges ysgwyd llaw Cais Tystysgrif annisgwyl.
+ssl-error-rx-unexpected-hello-done = Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd Cwblhawyd annisgwyl.
+ssl-error-rx-unexpected-cert-verify = Mae SSL wedi derbyn neges ysgwyd llaw Dilysu Tystysgrif annisgwyl.
+ssl-error-rx-unexpected-client-key-exch = Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Cleient annisgwyl.
+ssl-error-rx-unexpected-finished = Mae SSL wedi derbyn neges ysgwyd llaw Terfynnu annisgwyl.
+ssl-error-rx-unexpected-change-cipher = Mae SSL wedi derbyn cofnod Manyleb Seiffr Newid annisgwyl.
+ssl-error-rx-unexpected-alert = Mae SSL wedi derbyn cofnod Rhybudd annisgwyl.
+ssl-error-rx-unexpected-handshake = Mae SSL wedi derbyn cofnod Ysgwyd Llaw annisgwyl.
+ssl-error-rx-unexpected-application-data = Mae SSL wedi derbyn cofnod Data Rhaglen annisgwyl.
+ssl-error-rx-unknown-record-type = Mae SSL wedi derbyn cofnod gyda math data anhysbys.
+ssl-error-rx-unknown-handshake = Mae SSL wedi derbyn negws ysgwyd llaw gyda math data anhysbys.
+ssl-error-rx-unknown-alert = Mae SSL wedi derbyn cofnod rhybudd gyda math disgrifiad anhysbys.
+ssl-error-close-notify-alert = Mae cyfoed SSL wedi cau'r cysylltiad.
+ssl-error-handshake-unexpected-alert = Nid oess y cyfoed SSL yn disgwyl y negws ysgwyd llaw dderbyniodd.
+ssl-error-decompression-failure-alert = Nid oess y cyfoed SSL yn gallu datgywasgu'r cofnod SSL y derbyniodd yn llwyddiannus.
+ssl-error-handshake-failure-alert = Nid oedd cyfoed SSL yn gallu negydu set dderbyniol o baramedrau diogelwch.
+ssl-error-illegal-parameter-alert = Gwrthododd cyfoed SSL neges ysgwyd llaw oherwydd cynnwys annerbyniol.
+ssl-error-unsupported-cert-alert = Nid yw cyfoed SSL yn cynnal tystysgrifau o'r matha mae wedi eu derbyn.
+ssl-error-certificate-unknown-alert = Mae gan gyfoed SSL anhawster amhenodol gyda'r dystysgrif mae wedi ei derbyn.
+ssl-error-generate-random-failure = Profodd SSL fethiant a'o gynhyrchydd rhifau hap.
+ssl-error-sign-hashes-failure = Methu llofnodi data digidol angenrheidiol ar gyfer dilysu eich tystysgrif.
+ssl-error-extract-public-key-failure = Roedd SSL yn methu tynnu'r allwedd gyhoeddus o dystysgrif y cyfoed.
+ssl-error-server-key-exchange-failure = Bu methiant amhenodol wrth brosesu ysgwyd llaw Cyfnewid Allwedd Gweinydd SSL.
+ssl-error-client-key-exchange-failure = Bu methiant amhenodol wrth brosesu ysgwyd llaw Cyfnewid Allwedd Gweinydd SSL.
+ssl-error-encryption-failure = Methodd algorithm amgryptio swmp data yn y swit seiffr hwn.
+ssl-error-decryption-failure = Methodd algorithm dadgryptio swmp data yn y swit seiffr hwn.
+ssl-error-socket-write-failure = Merhodd ymgais i ysgrifennu data amgryptiedig i'r soced gwaelodol.
+ssl-error-md5-digest-failure = Methodd swyddogaeth crynhoi MD5.
+ssl-error-sha-digest-failure = Methodd swyddogaeth crynhoi SHA-1.
+ssl-error-mac-computation-failure = Methodd cyfrifiant MAC.
+ssl-error-sym-key-context-failure = Methu creu cyd-destun Allwedd Symetrig.
+ssl-error-sym-key-unwrap-failure = Methu dadlapio'r allwedd Symetrig yn neges Cyfnewid Allwedd Cleient.
+ssl-error-pub-key-size-limit-exceeded = Ceisiodd Gweinydd SSL â defnyddio allwedd gyhoeddus domestig gyda swit seiffr allforio.
+ssl-error-iv-param-failure = Methodd cod PKCS11 â throsi IV i baram.
+ssl-error-init-cipher-suite-failure = Methu cychwyn y swit seiffr hwn.
+ssl-error-session-key-gen-failure = Methodd y cleient â chynhyrchu allweddi sesiwn ar gyfer sesiwn SSL.
+ssl-error-no-server-key-for-alg = Nid oes gan y gweinydd allwedd ar gyfer ymgais algoryddm cyfnewid allweddi.
+ssl-error-token-insertion-removal = Mewnosodwyd neu dynnwyd tocyn PKCS#11 wrth i'r weithred fod mewn grym.
+ssl-error-token-slot-not-found = Ni fu modd canfod tocyn PKCS#11 i gyflawni'r weithredu.
+ssl-error-no-compression-overlap = Methu cyfathrebu'n ddiogel gyda'r cyfoed: dim algorithmau(au) cywasgu cyffredin.
+ssl-error-handshake-not-completed = Methu cychwyn ysgwyd llaw SSL arall nes i'r ysgwyd llaw cyfredol ddod i ben.
+ssl-error-bad-handshake-hash-value = Wedi derbyn gwerthoedd hash ysgwyd llaw anghywir gan y cyfoed.
+ssl-error-cert-kea-mismatch = Nid oes modd defnyddio'r dystysgrif hon gyda'r algorythm cyfnewid allwedd hwn.
+ssl-error-no-trusted-ssl-client-ca = Nid oes ymddiriedaeth i awdurdod tystysgrifo ar gyfer dilysu cleient SSL.
+ssl-error-session-not-found = Nid yw enw sesiwn SSL y cleient wedi ei ganfod yn storfa dros dro sesiwn y gweinydd.
+ssl-error-decryption-failed-alert = Methodd y cyfoed â dadgryptio cofnod SSL mae wedi ei derbyn.
+ssl-error-record-overflow-alert = Derbyniodd y cyfoed gofnod SSL sy'n hirach na'r hyn ganiateir.
+ssl-error-unknown-ca-alert = Nid yw'r cyfoed yn adnabod nac ymddiried yn y AT sydd wedi cyhoeddi eich tystysgrif.
+ssl-error-access-denied-alert = Derbyniodd y cyfoed dystysgrif dilys , ond gwrthodwyd mynediad.
+ssl-error-decode-error-alert = Nid oedd y cyfoed yn gallu dadgodio neges ysgwyd llaw SSL.
+ssl-error-decrypt-error-alert = Mae'r cyfoed yn cofnodi methiant llofnod dilysu neu gyfnewid allweddi.
+ssl-error-export-restriction-alert = Mae'r cyfoed yn cofnodi negodi nad yw'n gytûn â'r rheoliadau allforio.
+ssl-error-protocol-version-alert = Mae'r cofnod yn cofnodi ferwiwn protocol anghymarus neu heb ei gynnal.
+ssl-error-insufficient-security-alert = Mae'r gweinydd angen seiffr mwy diogel na'r rhai sy'n cael eu cynnal gan y cleient.
+ssl-error-internal-error-alert = Mae'r cyfoed yn nodi gwall mewnol.
+ssl-error-user-canceled-alert = Mae'r cyfoed wedi diddymu ysgwyd llaw.
+ssl-error-no-renegotiation-alert = Nid yw'r cyfoed yn caniatáu ailnegodi paramedrau diogelwch SSL.
+ssl-error-server-cache-not-configured = Nid yw storfa dros dro gweinydd SSL wedi ei ffurfweddu na'i analluogi ar gyfer y soced hwn.
+ssl-error-unsupported-extension-alert = Nid yw'r cyfoed SSL yn cynnal yr estyniad helo TLS gofynnwys amdano.
+ssl-error-certificate-unobtainable-alert = Nid yw'r cyfoed SSL y gallu cael eich tystysgrif o'r URL darparwyd.
+ssl-error-unrecognized-name-alert = Nid oes gan y cyfoed SSL dystysgrif ar gyfer yr enw DNS gofynnwyd amdani.
+ssl-error-bad-cert-status-response-alert = Nid oedd y cyfoed SSL yn gallu cael ymateb OCSP ar gyfer ei dystysgrif.
+ssl-error-bad-cert-hash-value-alert = Adroddodd cyfoed yr SSL gwerth hash tystysgrif gwael.
+ssl-error-rx-unexpected-new-session-ticket = Mae SSL wedi derbyn neges ysgwyd llaw Tocyn Sesiwn Newydd annisgwyl.
+ssl-error-rx-malformed-new-session-ticket = Mae SSL wedi derbyn neges ysgwyd llaw Tocyn Sesiwn Newydd.
+ssl-error-decompression-failure = Mae SSL wedi derbyn cofnod cywasgedig nad oedd modd ei datgywasgu.
+ssl-error-renegotiation-not-allowed = Nid oes modd ail negodi ar y soced SSL hwn.
+ssl-error-unsafe-negotiation = Ceisiodd y cyfoed ysgwyd llaw hen ffurf (bregus posib).
+ssl-error-rx-unexpected-uncompressed-record = Derbyniodd SSL gofnod datgywasgedig annisgwyl.
+ssl-error-weak-server-ephemeral-dh-key = Derbyniodd SSL allwedd gwan Diffie-Hellman darfodedig yn neges ysgwyd llaw Cyfnewidiad Allwedd Gweinydd.
+ssl-error-next-protocol-data-invalid = Derbyniodd SSL ddata estyniad NPN annilys.
+ssl-error-feature-not-supported-for-ssl2 = Nid yw'r nodwedd SSL hwn yn cael ei gynnal ar gyfer cysylltiadau SSL 2.0.
+ssl-error-feature-not-supported-for-servers = Nid yw'r nodweddion SSL hyn yn cael eu cynnal ar weinyddion.
+ssl-error-feature-not-supported-for-clients = Nid yw'r nodweddion SSL hyn yn cael eu cynnal ar raglenni.
+ssl-error-invalid-version-range = Nid ys ystod fersiwn SSL yn ddilys.
+ssl-error-cipher-disallowed-for-version = Dewisodd cyfoed swît seiffr SSL sydd wedi ei atal ar gyfer y protocol fersiwn yma.
+ssl-error-rx-malformed-hello-verify-request = Mae SSL wedi derbyn neges ysgwyd llaw Hello Verify Request anffurf.
+ssl-error-rx-unexpected-hello-verify-request = Mae SSL wedi derbyn neges ysgwyd llaw Hello Verify Request annisgwyl.
+ssl-error-feature-not-supported-for-version = Nid yw'r nodwedd SSL hwn yn cael ei gynnal ar gyfer y fersiwn protocol.
+ssl-error-rx-unexpected-cert-status = Mae SSL wedi derbyn neges ysgwyd llaw Statws Tystysgrif annisgwyl.
+ssl-error-unsupported-hash-algorithm = Algorithm hash anghynaledig wedi ei ddefnyddio gan gyfoed TLS.
+ssl-error-digest-failure = Methodd swyddogaeth crynhoi.
+ssl-error-incorrect-signature-algorithm = Algorithm llofnod anghywir wedi ei bennu mewn elfen llofnod digidol.
+ssl-error-next-protocol-no-callback = Roedd yr estyniad negydu protocol yn barod ond cafodd yr adalw ei glirio cyn fod ei angen.
+ssl-error-next-protocol-no-protocol = Nid yw'r gweinydd yn cynnal protocolau mae'r client yn ei hysbysu yn yr estyniad ALPN.
+ssl-error-inappropriate-fallback-alert = Gwrthododd y gweinydd yr ysgwyd llaw oherwydd i'r client israddio i fersiwn TLS is na mae'r gweinydd yn ei gynnal.
+ssl-error-weak-server-cert-key = Mae tystysgrif y gweinydd yn cynnwys allwedd gyhoeddus sy'n rhy wan.
+ssl-error-rx-short-dtls-read = Dim digon o le ar y byffer ar gyfer cofnod DTLS.
+ssl-error-no-supported-signature-algorithm = Heb ffurfweddu algorithm llofnod TLS sy'n cael ei gynnal.
+ssl-error-unsupported-signature-algorithm = Mae'r cyfoed yn defnyddio cyfuniad o lofnod a'r algorithm hash sydd ddim yn cael ei gynnal.
+ssl-error-missing-extended-master-secret = Mae'r cyfoed wedi ceisio ailgychwyn heb yr estyniad extended_master_secret cywir.
+ssl-error-unexpected-extended-master-secret = Mae'r cyfoed wedi ceisio ailgychwyn gyda estyniad extended_master_secret annisgwyl.
+sec-error-io = Digwyddodd gwall I/O yn ystod dilysu diogelwch.
+sec-error-library-failure = methiant llyfrgell diogelwch.
+sec-error-bad-data = llyfrgell diogelwch: derbyniwyd data gwael.
+sec-error-output-len = llyfrgell diogelwch: gwall hyd allbwn.
+sec-error-input-len = mae'r llyfrgell diogelwch wedi profi gwall hyd mewnbwn.
+sec-error-invalid-args = llyfrgell diogewlch: ymrysonderau annilys.
+sec-error-invalid-algorithm = llyfrgell diogewlch: algorithm annilys.
+sec-error-invalid-ava = llyfrgell diogelwch: AVA annilys.
+sec-error-invalid-time = Llinyn amser fformatiwyd yn annilys.
+sec-error-bad-der = llyfrgell diogelwch: neges amgodiad-DER wedi ei fformatio'n annilys.
+sec-error-bad-signature = Mae gan y tystysgrif cyfoed lofnod annilys.
+sec-error-expired-certificate = Tystysgrif Cyfoed wedi dod i ben.
+sec-error-revoked-certificate = Tystysgrif Cyfoed wedi ei atal.
+sec-error-unknown-issuer = Cyhoeddwr Tystysgrif Cyfoed heb ei adnabod.
+sec-error-bad-key = Allwedd cyhoeddus y cyfoed yn annilys.
+sec-error-bad-password = Mae'r cyfrinair diogelwch yn anghywir.
+sec-error-retry-password = Cyfrinair newydd yn anghywir. Ceisiwch eto.
+sec-error-no-nodelock = llyfrgell diogelwch: dim clo nod.
+sec-error-bad-database = llyfrgell diogewlch: cronfa ddata gwael.
+sec-error-no-memory = llyfrgell diogewlch: methiant dynodicof.
+sec-error-untrusted-issuer = Cyhoeddwr tystysgrif cyfoed wedi ei nodi fel annibynadwy gan y defnyddiwr.
+sec-error-untrusted-cert = Tstysgrif cyfoed wedi ei nodi fel annibynadwy gan y defnyddiwr.
+sec-error-duplicate-cert = Mae'r tystysgrif yn bodoli yn eich cronfa ddata.
+sec-error-duplicate-cert-name = Mae enw'r dystysgrif llwythwyd i lawr yn dyblygu un sydd yn eich cronfa ddata.
+sec-error-adding-cert = Gwall ychwanegu tystysgrif i'r gronfa ddata.
+sec-error-filing-key = Gwall ail-lanw allwedd ar gyfer y dystysgrif.
+sec-error-no-key = Nid oes modd dod o hyd i allwedd breifat y dystysgrif yng gronfa ddata allweddi
+sec-error-cert-valid = Mae'r dystysgrif yn ddilys.
+sec-error-cert-not-valid = Nid yw'r dystysgrif yn ddilys.
+sec-error-cert-no-response = Llyfrgell Tyst: Dim Ymateb
+sec-error-expired-issuer-certificate = Ma tystysgrif cyhoeddwr y dystysgrif wedi dod i ben. Gwiriwch ddyddiad ac amser eich system.
+sec-error-crl-expired = Mae CRL cyhoeddwr y dystysgrif wedi dod i ben. Diweddarwch neu gwiriwch ddyddiad ac amser eich system.
+sec-error-crl-bad-signature = Mae i CRL cyhoeddwr y dystysgrif lofnod annilys.
+sec-error-crl-invalid = Mae i'r CRL newydd fformat annilys.
+sec-error-extension-value-invalid = Mae gwerth estyniad tystysgrif yn annilys.
+sec-error-extension-not-found = Heb ganfod estyniad tystysgrif.
+sec-error-ca-cert-invalid = Tystysgrif y cyhoeddwr yn annilys.
+sec-error-path-len-constraint-invalid = Mae cyfyniad hyd llwybr y dystysgrif yn annilys.
+sec-error-cert-usages-invalid = Mae maes defnydd tystysgrif yn annilys.
+sec-internal-only = **Modiwl Mewnol YN UNIG**
+sec-error-invalid-key = Nid yw'r allwedd yn cynnal y weithred hon.
+sec-error-unknown-critical-extension = Mae'r dystysgrif yn cynnwys estyniad critigol anhysbys.
+sec-error-old-crl = Nid yw'r CRL yn hwyrach na'r un gyfredol.
+sec-error-no-email-cert = Heb ei hamgryptio na'i harwyddo: nid oes gennych dystysgrif e-bost eto.
+sec-error-no-recipient-certs-query = Heb ei hamgryptio: nid oes gennych dystysgrif ar gyfer pob un derbynnydd.
+sec-error-not-a-recipient = Methu dadgryptio: nid ydych yn dderbynnydd, neu heb ganfod tystysgrif cytûn neu allwedd breifat.
+sec-error-pkcs7-keyalg-mismatch = Methu dadgryptio: nid yw amgryptiad yr algorithm yn gytûn â'ch tystysgrif.
+sec-error-pkcs7-bad-signature = Methodd dilysu llofnod: heb ganfod llofnodwr, wedi canfod gormod o lofnodwyr neu data amhriodol neu llwgr.
+sec-error-unsupported-keyalg = Allwedd algorithm heb ei gynnal neu anhysbys.
+sec-error-decryption-disallowed = Methu dadgryptio: wedi ei amgryptio gan ddefnyddio algorithm gwaharddedig neu faint allwedd.
+xp-sec-fortezza-bad-card = Nid yw cerdyn Fortezza wedi ei gychwyn yn gywir. Tynnwch y cerdyn a'i ddychwelyd ar y cyhoeddwr.
+xp-sec-fortezza-no-card = Heb ganfod cerdyn Fortezza
+xp-sec-fortezza-none-selected = Heb ddewis cerdyn Fortezza
+xp-sec-fortezza-more-info = Dewiswch bersonoliaeth i dderbyn mwy o wybodaeth amdano
+xp-sec-fortezza-person-not-found = Heb ddarganfod personoliaeth
+xp-sec-fortezza-no-more-info = Dim rhagor o wybodaeth ar Personoliaeth hwnnw
+xp-sec-fortezza-bad-pin = Pin annilys
+xp-sec-fortezza-person-error = Methu cychwyn personoliaethau Fortezza.
+sec-error-no-krl = Heb ganfod KRL ar gyfer tystysgrif y wefan.
+sec-error-krl-expired = Mae KRL y wefan wedi dod i ben.
+sec-error-krl-bad-signature = Mae llofnod annilys i KRL tystysgrif y wefan.
+sec-error-revoked-key = Mae allwedd tystysgrif y wefan honn wedi ei therfynnu.
+sec-error-krl-invalid = Mae fformat annilys i'r KRL newydd.
+sec-error-need-random = llyfrgell diogelwch: angen data hap.
+sec-error-no-module = llyfrgell diogelwch: nid oes modiwl diogelwch all gyflawni'r weithred angenrheidiol.
+sec-error-no-token = Nid yw'r cerdyn neu docyn diogelwch yn bodoli, angen ei gychwyn neu wedi ei dynnu.
+sec-error-read-only = llyfrgell diogelwch: cronfa ddata darllen yn unig.
+sec-error-no-slot-selected = Heb ddewis slot neu docyn.
+sec-error-cert-nickname-collision = Mae tystysgrif gyda'r un llysenw yn bodoli eisoes.
+sec-error-key-nickname-collision = Mae allwedd gyda'r un llysenw yn bodoli eisoes.
+sec-error-safe-not-created = gwall wrth greu gwrthrych diogel
+sec-error-baggage-not-created = gwall werth greu gwrthrych pecyn
+xp-java-remove-principal-error = Methu tynnu'r prif
+xp-java-delete-privilege-error = Methu dileu'r fraint
+xp-java-cert-not-exists-error = Nid oes gan y prif dystysgrif
+sec-error-bad-export-algorithm = Nid oes caniatâd i'r algorithm angenrheidiol.
+sec-error-exporting-certificates = Gwall wrth geisio allforio tystysgrifau.
+sec-error-importing-certificates = Gwall wrth geisio mewnforio tystysgrifau.
+sec-error-pkcs12-decoding-pfx = Methu mewnforio. Gwall dadgodio. Nid yw'r ffeil yn ddilys.
+sec-error-pkcs12-invalid-mac = Methu mewnforio. MAC annilys. Cyfrinair anghywir neu ffeil llwgr.
+sec-error-pkcs12-unsupported-mac-algorithm = Methu mewnforio. Nid yw'r algorithm MAC yn cael ei gynnal.
+sec-error-pkcs12-unsupported-transport-mode = Methu mewnforio. Dim ond cywirdeb cyfrinair a moddau preifatrwydd sy'n cael eu cynnal.
+sec-error-pkcs12-corrupt-pfx-structure = Methu mewnforio. Mae strwythur y ffeil yn llwgr.
+sec-error-pkcs12-unsupported-pbe-algorithm = Methu mewnforio. Nid yw algorithm yr amgryptio'n cael ei gynnal.
+sec-error-pkcs12-unsupported-version = Methu mewnforio. Nid yw fersiwn y ffeil yn cael ei chynnal.
+sec-error-pkcs12-privacy-password-incorrect = Methu mewnforio. Cyfrinair preifatrwydd anghywir.
+sec-error-pkcs12-cert-collision = Methu mewnforio. Mae'r un llysenw yn bodoli eisoes yn y gronfa ddata.
+sec-error-user-cancelled = Pwysodd y defnyddiwr diddymu.
+sec-error-pkcs12-duplicate-data = Heb ei fewnforio, eisoes yn y gronfa ddata.
+sec-error-message-send-aborted = Heb anfon y neges.
+sec-error-inadequate-key-usage = Defnydd allwedd y dystysgrif yn annigonol ar gyfer y weithred ymgeisiwyd.
+sec-error-inadequate-cert-type = Nid yw'r math o dystysgrif wedi ei gymeradwyo ar gyfer y rhaglen.
+sec-error-cert-addr-mismatch = Nid yw'r cyfeiriad yn y dysstysgrif llofnodi yn cydfynd â'r cyferiad ym mhenyn y neges.
+sec-error-pkcs12-unable-to-import-key = Methu mewnforio. Gwall wrth geisio mewnforio'r allwedd breifat.
+sec-error-pkcs12-importing-cert-chain = Methu mewnforio. Gwall wrth geisio mewnforio cadwyn tystysgrif.
+sec-error-pkcs12-unable-to-locate-object-by-name = Methu allforio. Methu lleoli tystysgrif neu allwedd yn ôl tystysgrif.
+sec-error-pkcs12-unable-to-export-key = Methu allforio. Nid oedd modd canfod yr Allwedd Breifat a'i hallforio.
+sec-error-pkcs12-unable-to-write = Methu allforio. Methu ysgrifennu i'r ffeil allforio.
+sec-error-pkcs12-unable-to-read = Methu mewnforio. Methu darllen y ffeil mewnforio.
+sec-error-pkcs12-key-database-not-initialized = Methu allforio. Cronfa ddata'r allwedd yn llwgr neu wedi ei dileu.
+sec-error-keygen-fail = Methu cynhyrchu par o allweddi cyhoeddus/preifat.
+sec-error-invalid-password = Mae'r cyfrinair rhoddwyd yn annilys. Dewiswch un arall.
+sec-error-retry-old-password = Mae'r hen gyfrinair wedi ei gosod yn anghywir. Ceisiwch eto.
+sec-error-bad-nickname = Mae llysenw'r dystysgrif yn cael ei defnyddio eisoes.
+sec-error-not-fortezza-issuer = Mae gan y cadwyn FORTEZZA cyfoed dystysgrif an FORTEZZA.
+sec-error-cannot-move-sensitive-key = Nid oes modd symud allwedd sensitif i'r slot lle mae ei hangen.
+sec-error-js-invalid-module-name = Enw modiwl annilys.
+sec-error-js-invalid-dll = Llwybr/enw ffeil modiwl annilys
+sec-error-js-add-mod-failure = Methu ychwanegu modiwl
+sec-error-js-del-mod-failure = Methu dileu modiwl
+sec-error-old-krl = Nid yw'r KRL newydd yn hwyrach na'r un cyfredol.
+sec-error-ckl-conflict = Mae gan y CKL gyhoeddwr gwahanol i'r CKL cyfredol. Dilëwch y CKL cyfredol.
+sec-error-cert-not-in-name-space = Nid oes gan Awdurdod Tystysgrifo'r dystysgrif hon hawl i gyhoeddi tystysgrif yn yr enw hwn.
+sec-error-krl-not-yet-valid = Nid yw rhestr dileu'r allwedd ar gyfer y dystysgrif yn ddilys eto.
+sec-error-crl-not-yet-valid = Nid yw rhestr dileu'r dystysgrif ar gyfer y dystysgrif yn ddilys eto.
+sec-error-unknown-cert = Nid oedd modd canfod y dystysgrif ofynnol.
+sec-error-unknown-signer = Nid oedd modd canfod tystysgrif y llofnodwr.
+sec-error-cert-bad-access-location = Mae gan leoliad gweinydd statws y dystysgrif fformat annilys.
+sec-error-ocsp-unknown-response-type = Nid oes modd dadgodio ymateb OCSP yn llawn; mae o fath anhysbys.
+sec-error-ocsp-bad-http-response = Dychwelodd gweinydd OCSP ddata HTTP annisgwyl/annilys.
+sec-error-ocsp-malformed-request = Mae'r gweinydd OCSP wedi pennu'r cais fel un llwgr neu heb ei ffurfio'n gywir.
+sec-error-ocsp-server-error = Profodd y gweinydd OCSP wall mewnol.
+sec-error-ocsp-try-server-later = Mae gweinydd yr OCSP yn awgrymu y dylech geisio eto.
+sec-error-ocsp-request-needs-sig = Mae angen llofnod ar gyfer y gweinydd OCSP.
+sec-error-ocsp-unauthorized-request = Mae'r gweinydd OCSP wedi gwrthod y cais fel un anawdurdodedig.
+sec-error-ocsp-unknown-response-status = Dychwelodd y gweinydd OCSP statws heb ei gydnabod.
+sec-error-ocsp-unknown-cert = Nid oes gan y gweinydd OCSP statws ar gyfer y dystysgrif.
+sec-error-ocsp-not-enabled = Rhaid galluogi OCSP cyn cyflawni'r weithred.
+sec-error-ocsp-no-default-responder = Rhaid gosod ymatebwr rhagosodedig yr OCSP cyn cyflawni'r weithred.
+sec-error-ocsp-malformed-response = Roedd ymateb y gweinydd OCSP yn llwgr neu heb ei ffurfio'n gywir.
+sec-error-ocsp-unauthorized-response = Nid oes gan lofnodwr ymateb yr OCSP yr awdurdod i ddarparu statws y dystysgrif.
+sec-error-ocsp-future-response = Nid yw ymateb yr OCSP nyn ddilys eto (mae'n cynnwys dyddiad yn y dyfodol).
+sec-error-ocsp-old-response = Mae ymateb yr OCSP yn cynnwys hen ddata.
+sec-error-digest-not-found = Heb ganfod Crynodeb CMS neu PKCS #7 yn y neges gyda'r llofnod.
+sec-error-unsupported-message-type = Nid yw'r math o neges CMS neu PKCS #7 yn cael eu cynnal.
+sec-error-module-stuck = Nid oeddd modd tynnu modiwl PKCS #11 am ei fod yn cael ei ddefnyddio.
+sec-error-bad-template = Methu dadgodio data ASN.1. Roedd y templed yn annilys.
+sec-error-crl-not-found = Methu canfod CRL cytûn.
+sec-error-reused-issuer-and-serial = Rydych yn ceisio mewnforio tystysgrif gyda'r un cyhoeddwr/cyfres a'r dystysgrif gyfredol, ond nid yr un dystysgrif ydyw.
+sec-error-busy = Meddodd yr NSS â chau. Gwrthychau yn dal mewn defnydd.
+sec-error-extra-input = Mae'r neges DER amgodedig yn cynnwys data ychwanegol heb ei ddefnyddio.
+sec-error-unsupported-elliptic-curve = Cromlin eliptig heb ei gynnal.
+sec-error-unsupported-ec-point-form = Ffurf pwynt cromlin eliptig heb ei gynnal.
+sec-error-unrecognized-oid = Adnabyddwr Gwrthrychau Anhysbys.
+sec-error-ocsp-invalid-signing-cert = Tysytysgrif llofnodi OCSP anniltys yn ymateb yr OCSP.
+sec-error-revoked-certificate-crl = Mae'r dystysgrif wedi ei diddymu yn rhestr diddymu cyhoeddwr y dystysgrif.
+sec-error-revoked-certificate-ocsp = Mae tystysgrif adrodd ymatebion OCSP y cyhoeddwr wedi ei diddymu.
+sec-error-crl-invalid-version = Mae gan Rhestr Diddymu Tystysgrifau'r Cyhoeddwr rhif fersiwn anhysbys.
+sec-error-crl-v1-critical-extension = Mae gan Rhestr Diddymu Tystysgrif V1 y cyhoeddwr estyniad critigol.
+sec-error-crl-unknown-critical-extension = Mae gan Rhestr Diddymu Tystysgrif V2 y cyhoeddwr estyniad critigol anhysbys.
+sec-error-unknown-object-type = Gwrthrych o fath anhysbys wedi ei bennu.
+sec-error-incompatible-pkcs11 = Mae gyrrwr PKCS #11 yn tarfu'r manyleb mewn dull anghymarus.
+sec-error-no-event = Mae digwyddiad slot newydd ar gael ar hyn o bryd.
+sec-error-crl-already-exists = Mae'r CRL yn bodoli eisoes.
+sec-error-not-initialized = Nid yw'r NSS wedi ei gychwyn.
+sec-error-token-not-logged-in = Methodd y weithred gan nad yw tocyn PKCS#11 wedi ei fewngofnodi.
+sec-error-ocsp-responder-cert-invalid = Mae ffurfweddiad tystysgrif ymatebwr OCSP yn anilys.
+sec-error-ocsp-bad-signature = Mae gan ymateb yr OCSP lofnod annilys.
+sec-error-out-of-search-limits = Mae chwilio dilysu'r dystysgrif tu llan i derfynnau ei chwilio
+sec-error-invalid-policy-mapping = Mae mapio polisi yn cynnwys anypolicy
+sec-error-policy-validation-failed = Mae cadwyn y dystysgrif yn methu'r dilysiad polisi
+sec-error-unknown-aia-location-type = Math lleoliad anhysbys yn estyniad tystysgrif AIA
+sec-error-bad-http-response = Dychwelodd y gweinydd ymateb HTTP gwael
+sec-error-bad-ldap-response = Dychwelodd y gweinydd ymateb LDAP gwael
+sec-error-failed-to-encode-data = Methwyd amgosio data gydag amgodiwr ASN1
+sec-error-bad-info-access-location = Lleoliad mynediad gwybodaeth gwael mewn estyniad tystysgrif
+sec-error-libpkix-internal = Digwyddodd gwall mewnol libpkix yn ystod dilysiad tystysgrif.
+sec-error-pkcs11-general-error = Dychwelodd modiwl PKCS #11 CKR_GENERAL_ERROR, gan awgrymu fod gwall anadferadwy wedi digwydd.
+sec-error-pkcs11-function-failed = Dychwelodd PKCS #11 CKR_FUNCTION_FAILED, gan awgrymu nad oedd modd cyflawni'r swyddogaeth ofynnol. Efallai bydd cyflawni'r un weithred eto'n llwyddo.
+sec-error-pkcs11-device-error = Dychwelodd modiwl PKCS #11 CKR_DEVICE_ERROR, gan awgrymu fod yna broblem gyda'r tocyn neu'r slot.
+sec-error-bad-info-access-method = Dull mynediad gwybodaeth anhysbys mewn estyniad tystysgrif.
+sec-error-crl-import-failed = Gwall wrth geisio mewnforio CRL.
+sec-error-expired-password = Mae'r cyfrinair wedi dod i ben.
+sec-error-locked-password = Mae'r cyfrinair wedi ei gloi.
+sec-error-unknown-pkcs11-error = Gwall PKCS #11 anhysbys.
+sec-error-bad-crl-dp-url = URL annilys neu heb ei gynnal yn enw pwynt dosbarthiad CRL.
+sec-error-cert-signature-algorithm-disabled = Cafodd y dystysgrif ei llofnodi gan ddefnyddio algorithm llofnod sydd wedi ei analluogi am nad yw'n ddiogel.
+mozilla-pkix-error-key-pinning-failure = Mae'r gweinydd yn defnyddio pinio allwedd (HPKP) ond nid oedd modd cynhyrchu cadwyn tystysgrif ymddiriedig sy'n cyd-fynd a'r set pinnau. Nid oes mod gwrthwneud torri pinio allweddi.
+mozilla-pkix-error-ca-cert-used-as-end-entity = Mae'r gweinydd yn defnyddio tystysgrif gydag estyniad cyfyngiadau sylfaenol sy'n ei ddynodi fel yr awdurdod tystysgrifo. Ar gyfer tystysgrifau sydd wedi eu rhyddhau'n briodol, ni ddylai hyn fod yn wir.
+mozilla-pkix-error-inadequate-key-size = Cyflwynodd y gweinydd dystysgrif sydd ag allwedd sy'n rhy fach i greu cysylltiad diogel.
+mozilla-pkix-error-v1-cert-used-as-ca = Defnyddiwyd tystysgrif X.509 fersiwn 1 nad yw'n angor ymddiriedaeth i gyhoeddi tystysgrif y wefan. Mae tystysgrifau X.509 fersiwn 1 yn anghymeradwy ac ni ddylent gael eu defnyddio i lofnodi tystysgrifau eraill.
+mozilla-pkix-error-not-yet-valid-certificate = Cyflwynodd y gweinydd dystysgrif nad yw eto'n ddilys.
+mozilla-pkix-error-not-yet-valid-issuer-certificate = Defnyddiwyd tystysgrif nad yw eto'n ddilys i gyhoeddi tystysgrif y gweinydd.
+mozilla-pkix-error-signature-algorithm-mismatch = Nid yw'r algorithm llofnod ym maes llofnod y dystysgrif yn cyd-fynd â'r algorithm ym maes signatureAlgorithm.
+mozilla-pkix-error-ocsp-response-for-cert-missing = Nid yw ymateb yr OCSP yn cynnwys statws y dystysgrif sy'n cael ei gwirio.
+mozilla-pkix-error-validity-too-long = Cyflwynodd y gweinydd dystysgrif sy'n ddilys am rhy hir.
+mozilla-pkix-error-required-tls-feature-missing = Mae'r nodwedd TLS angenrheidiol ar goll.
+mozilla-pkix-error-invalid-integer-encoding = Cyflwynodd y gweinydd dystysgrif sy'n cynnwys math annilys o amgodio integer. Mae'r rhesymau cyffredin yn cynnwys rhifau cyfresol negyddol, moduli RSA negyddol, ac amgodio nad ydynt eu hangen bellach.
+mozilla-pkix-error-empty-issuer-name = Cyflwynodd y gweinydd dystysgrif gydag enw cyhoeddwr penodol gwag.
+mozilla-pkix-error-additional-policy-constraint-failed = Methodd cyfyngiad polisi ychwanegol wrth ddilysu'r dystysgrif hon.
+mozilla-pkix-error-self-signed-cert = Nid oes modd ymddiried yn y dystysgrif am ei fod wedi ei hunanlofnodi.
diff --git a/l10n-cy/browser/browser/pageInfo.ftl b/l10n-cy/browser/browser/pageInfo.ftl
new file mode 100644
index 0000000000..bce1283e19
--- /dev/null
+++ b/l10n-cy/browser/browser/pageInfo.ftl
@@ -0,0 +1,272 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/. --
+
+page-info-window =
+    .style = width: 600px; min-height: 550px;
+
+copy =
+    .key = C
+menu-copy =
+    .label = Copïo
+    .accesskey = C
+
+select-all =
+    .key = A
+menu-select-all =
+    .label = Dewis Popeth
+    .accesskey = P
+
+close-dialog =
+    .key = w
+
+general-tab =
+    .label = Cyffredinol
+    .accesskey = C
+general-title =
+    .value = Teitl:
+general-url =
+    .value = Cyfeiriad:
+general-type =
+    .value = Math:
+general-mode =
+    .value = Modd Llunio:
+general-size =
+    .value = Maint:
+general-referrer =
+    .value = URL cyfeirio:
+general-modified =
+    .value = Newidiwyd:
+general-encoding =
+    .value = Amgodiad Testun:
+general-meta-name =
+    .label = Enw
+general-meta-content =
+    .label = Cynnwys
+
+media-tab =
+    .label = Cyfrwng
+    .accesskey = C
+media-location =
+    .value = Lleoliad:
+media-text =
+    .value = Testun Cysylltiedig:
+media-alt-header =
+    .label = Testun Arall
+media-address =
+    .label = Cyfeiriad
+media-type =
+    .label = Math
+media-size =
+    .label = Maint
+media-count =
+    .label = Cyfrif
+media-dimension =
+    .value = Maint:
+media-long-desc =
+    .value = Disgrifiad Hir:
+media-save-as =
+    .label = Cadw Fel…
+    .accesskey = A
+media-save-image-as =
+    .label = Cadw Fel…
+    .accesskey = e
+
+perm-tab =
+    .label = Caniatâd
+    .accesskey = C
+permissions-for =
+    .value = Caniatâd ar gyfer:
+
+security-tab =
+    .label = Diogelwch
+    .accesskey = D
+security-view =
+    .label = Darllen y Dystysgrif
+    .accesskey = D
+security-view-unknown = Anhysbys
+    .value = Anhysbys
+security-view-identity =
+    .value = Enw Gwefan
+security-view-identity-owner =
+    .value = Perchennog:
+security-view-identity-domain =
+    .value = Gwefan:
+security-view-identity-verifier =
+    .value = Gwirio gan:
+security-view-identity-validity =
+    .value = Daw i ben ar:
+security-view-privacy =
+    .value = Preifatrwydd a Hanes
+
+security-view-privacy-history-value = A ydw i wedi ymweld â'r wefan hon cyn heddiw?
+security-view-privacy-sitedata-value = A yw'r wefan yma'n yn cadw gwybodaeth ar fy nghyfrifiadur?
+
+security-view-privacy-clearsitedata =
+    .label = Clirio Data Cwcis a Data
+    .accesskey = C
+
+security-view-privacy-passwords-value = A ydw i wedi cadw unrhyw gyfrineiriau ar gyfer y wefan yma?
+
+security-view-privacy-viewpasswords =
+    .label = Gweld y Cyfrineiriau wedi eu Cadw
+    .accesskey = w
+security-view-technical =
+    .value = Manylion Technegol
+
+help-button =
+    .label = Cymorth
+
+## These strings are used to tell the user if the website is storing cookies
+## and data on the users computer in the security tab of pageInfo
+## Variables:
+##   $value (number) - Amount of data being stored
+##   $unit (string) - The unit of data being stored (Usually KB)
+
+security-site-data-cookies = Ydy, cwcis a { $value } { $unit } o ddata gwefan
+security-site-data-only = Ydy, { $value } { $unit } o ddata gwefan
+
+security-site-data-cookies-only = Ydy, cwcis
+security-site-data-no = Na
+
+image-size-unknown = Anhysbys
+page-info-not-specified =
+    .value = Heb ddiffinio
+not-set-alternative-text = Heb ddiffinio
+not-set-date = Heb ddiffinio
+media-img = Delwedd
+media-bg-img = Cefndir
+media-border-img = Ymyl
+media-list-img = Bwled
+media-cursor = Cyrchwr
+media-object = Gwrthych
+media-embed = Mewnblannu
+media-link = Eicon
+media-input = Mewnbwn
+media-video = Fideo
+media-audio = Sain
+saved-passwords-yes = Ydw
+saved-passwords-no = Na
+
+no-page-title =
+    .value = Tudalen heb Deitl:
+general-quirks-mode =
+    .value = Modd Quirks
+general-strict-mode =
+    .value = Modd cynnal safonau
+page-info-security-no-owner =
+    .value = Nid yw'r wefan yn darparu gwybodaeth am ei pherchnogaeth.
+media-select-folder = Dewis Ffolder i Gadw'r Delweddau
+media-unknown-not-cached =
+    .value = Anhysbys (heb ei storio dros dro)
+permissions-use-default =
+    .label = Defnyddio'r Rhagosodedig
+security-no-visits = Na
+
+# This string is used to display the number of meta tags
+# in the General Tab
+# Variables:
+#   $tags (number) - The number of meta tags
+general-meta-tags =
+    .value =
+        { $tags ->
+            [zero] Meta ({ $tags } tagiau)
+            [one] Meta (1 tag)
+            [two] Meta ({ $tags } dags)
+            [few] Meta ({ $tags } tag)
+            [many] Meta ({ $tags } tag)
+           *[other] Meta ({ $tags } tag)
+        }
+
+# This string is used to display the number of times
+# the user has visited the website prior
+# Variables:
+#   $visits (number) - The number of previous visits
+security-visits-number =
+    { $visits ->
+        [0] Na
+        [zero] Do, unwaith
+        [one] Do, { $visits } waith
+        [two] Do, { $visits } waith
+        [few] Do, { $visits } gwaith
+        [many] Do, { $visits } waith
+       *[other] Do, { $visits } gwaith
+    }
+
+# This string is used to display the size of a media file
+# Variables:
+#   $kb (number) - The size of an image in Kilobytes
+#   $bytes (number) - The size of an image in Bytes
+properties-general-size =
+    .value =
+        { $bytes ->
+            [zero] { $kb } KB ({ $bytes } beit)
+            [one] { $kb } KB ({ $bytes } beit)
+            [two] { $kb } KB ({ $bytes } beit)
+            [few] { $kb } KB ({ $bytes } beit)
+            [many] { $kb } KB ({ $bytes } beit)
+           *[other] { $kb } KB ({ $bytes } beit)
+        }
+
+# This string is used to display the type and number
+# of frames of a animated image
+# Variables:
+#   $type (string) - The type of a animated image
+#   $frames (number) - The number of frames in an animated image
+media-animated-image-type =
+    .value =
+        { $frames ->
+            [zero] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+            [one] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+            [two] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+            [few] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+            [many] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+           *[other] Delwedd { $type } (animeiddio, { $frames } ffrâm)
+        }
+
+# This string is used to display the type of
+# an image
+# Variables:
+#   $type (string) - The type of an image
+media-image-type =
+    .value = Delwedd { $type }
+
+# This string is used to display the size of a scaled image
+# in both scaled and unscaled pixels
+# Variables:
+#   $dimx (number) - The horizontal size of an image
+#   $dimy (number) - The vertical size of an image
+#   $scaledx (number) - The scaled horizontal size of an image
+#   $scaledy (number) - The scaled vertical size of an image
+media-dimensions-scaled =
+    .value = { $dimx }px × { $dimy }px (graddio i { $scaledx }px × { $scaledy }px)
+
+# This string is used to display the size of an image in pixels
+# Variables:
+#   $dimx (number) - The horizontal size of an image
+#   $dimy (number) - The vertical size of an image
+media-dimensions =
+    .value = { $dimx }px × { $dimy }px
+
+# This string is used to display the size of a media
+# file in kilobytes
+# Variables:
+#   $size (number) - The size of the media file in kilobytes
+media-file-size = { $size } KB
+
+# This string is used to display the website name next to the
+# "Block Images" checkbox in the media tab
+# Variables:
+#   $website (string) - The website name
+media-block-image =
+    .label = Rhwystro Delweddau o { $website }
+    .accesskey = B
+
+# This string is used to display the URL of the website on top of the
+# pageInfo dialog box
+# Variables:
+#   $website (string) - The url of the website pageInfo is getting info for
+page-info-page =
+    .title = Gwyb. Tud. - { $website }
+page-info-frame =
+    .title = Gwyb. Ffrâm - { $website }
diff --git a/l10n-cy/browser/browser/panicButton.ftl b/l10n-cy/browser/browser/panicButton.ftl
new file mode 100644
index 0000000000..cf6d196f6e
--- /dev/null
+++ b/l10n-cy/browser/browser/panicButton.ftl
@@ -0,0 +1,31 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+panic-button-open-new-window = Agor Ffenestr glân newydd
+panic-button-undo-warning = Nid oes modd dadwneud y weithred.
+panic-button-forget-button =
+    .label = Anghofio!
+
+## These strings are combined to form a complete sentence starting with
+## panic-main-timeframe-desc. For example: "Forget the last: Five minutes".
+## Please ensure that this remains the case in the translation.
+
+panic-main-timeframe-desc = Anghofio'r olaf:
+panic-button-5min =
+    .label = Pum munud
+panic-button-2hr =
+    .label = Dwy awr
+panic-button-day =
+    .label = 24 awr
+
+## These strings are combined to form a complete sentence starting with
+## panic-button-action-desc. For example: "Proceeding will: Delete Recent Cookies".
+## Please ensure that this remains the case in the translation.
+## Note also that some strings include <strong> tags for emphasis on the
+## words "Cookies", "History", "Tabs" and "Windows". The translation should do the same.
+
+panic-button-action-desc = Bydd parhau yn:
+panic-button-delete-cookies = Dileu <strong>Cwcis</strong> Diweddar
+panic-button-delete-history = Dileu <strong>Hanes</strong> Diweddar
+panic-button-delete-tabs-and-windows = Cau pob <strong>Tab</strong> a <strong>Ffenestr</strong>
diff --git a/l10n-cy/browser/browser/places.ftl b/l10n-cy/browser/browser/places.ftl
new file mode 100644
index 0000000000..3970c132a8
--- /dev/null
+++ b/l10n-cy/browser/browser/places.ftl
@@ -0,0 +1,71 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+places-open =
+    .label = Agor
+    .accesskey = A
+places-open-tab =
+    .label = Agor mewn Tab Newydd
+    .accesskey = w
+places-open-all-in-tabs =
+    .label = Agor pob Tab
+    .accesskey = T
+places-open-window =
+    .label = Agor mewn Ffenestr Newydd
+    .accesskey = N
+places-open-private-window =
+    .label = Agor mewn Ffenestr Breifat Newydd
+    .accesskey = F
+places-new-bookmark =
+    .label = Nod Tudalen Newydd…
+    .accesskey = N
+places-new-folder-contextmenu =
+    .label = Ffolder Newydd…
+    .accesskey = F
+places-new-folder =
+    .label = Ffolder Newydd…
+    .accesskey = F
+places-new-separator =
+    .label = Ymwahanydd Newydd
+    .accesskey = Y
+places-view =
+    .label = Golwg
+    .accesskey = w
+places-by-date =
+    .label = Yn ôl Dyddiad
+    .accesskey = D
+places-by-site =
+    .label = Yn ôl Gwefan
+    .accesskey = G
+places-by-most-visited =
+    .label = Ymwelwyd Amlaf
+    .accesskey = A
+places-by-last-visited =
+    .label = Ymwelwyd Diwethaf
+    .accesskey = D
+places-by-day-and-site =
+    .label = Yn ôl Dyddiad a Gwefan
+    .accesskey = Y
+places-history-search =
+    .placeholder = Hanes chwilio
+places-bookmarks-search =
+    .placeholder = Chwilio'r nodau tudalen
+places-delete-domain-data =
+    .label = Anghofio'r Wefan Hon
+    .accesskey = W
+places-sortby-name =
+    .label = Trefnu yn Ôl Enw
+    .accesskey = r
+places-properties =
+    .label = Priodweddau
+    .accesskey = P
+# Managed bookmarks are created by an administrator and cannot be changed by the user.
+managed-bookmarks =
+    .label = Nodau Tudalen wedi'u rheoli
+# This label is used when a managed bookmarks folder doesn't have a name.
+managed-bookmarks-subfolder =
+    .label = Is-ffolder
+# This label is used for the "Other Bookmarks" folder that appears in the bookmarks toolbar.
+other-bookmarks-folder =
+    .label = Nodau Tudalen Eraill
diff --git a/l10n-cy/browser/browser/policies/policies-descriptions.ftl b/l10n-cy/browser/browser/policies/policies-descriptions.ftl
new file mode 100644
index 0000000000..8e6d52f06b
--- /dev/null
+++ b/l10n-cy/browser/browser/policies/policies-descriptions.ftl
@@ -0,0 +1,114 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## The Enterprise Policies feature is aimed at system administrators
+## who want to deploy these settings across several Firefox installations
+## all at once. This is traditionally done through the Windows Group Policy
+## feature, but the system also supports other forms of deployment.
+## These are short descriptions for individual policies, to be displayed
+## in the documentation section in about:policies.
+
+policy-3rdparty = Gosodwch bolisïau y gall WebExtensions gael mynediad atyn nhw trwy chrome.storage.managed.
+policy-AppAutoUpdate = Galluogi neu analluogi diweddaru rhaglen yn awtomatig.
+policy-AppUpdateURL = Gosod URL diweddaru ap cyfaddas.
+policy-Authentication = Ffurfweddu dilysu integredig ar gyfer gwefannau sy'n ei gefnogi.
+policy-BlockAboutAddons = Rhwystro mynediad i'r Rheolwr Ychwanegion (about:addons)
+policy-BlockAboutConfig = Rhwystro mynediad i'r dudalen about:config.
+policy-BlockAboutProfiles = Rhwystro mynediad i'r dudalen about:profiles.
+policy-BlockAboutSupport = Rhwystro mynediad i'r dudalen about:support.
+policy-Bookmarks = Creu nodau tudalen yn y bar offer Nodau Tudalen, dewislen Nodau Tudalen neu ffolder penodol o'u mewn.
+policy-CaptivePortal = Galluogi neu analluogi'r cymorth porth caeth.
+policy-CertificatesDescription = Ychwanegu tystysgrifau neu ddefnyddio tystysgrifau mewnol.
+policy-Cookies = Caniatáu neu wrthod i wefannau osod cwcis.
+policy-DisabledCiphers = Analluogi seifferau.
+policy-DefaultDownloadDirectory = Gosod y cyfeiriadur llwytho i lawr rhagosodedig.
+policy-DisableAppUpdate = Rhwystro'r wefan rhag diweddaru.
+policy-DisableBuiltinPDFViewer = Analluogi PDF.js, y dangosydd PDF mewnol yn { -brand-short-name }.
+policy-DisableDefaultBrowserAgent = Atal asiant y porwr rhagosodedig rhag cymryd unrhyw gamau. Dim ond yn berthnasol i Windows; nid oes gan lwyfannau eraill yr asiant.
+policy-DisableDeveloperTools = Rhwystro mynediad i'r offer datblygwr.
+policy-DisableFeedbackCommands = Analluogi gorchmynion rhag anfon adborth o'r ddewislen Cymorth (Cyflwyno Adborth ac Adrodd ar Wefan Dwyllodrus).
+policy-DisableFirefoxAccounts = Analluogi gwasanaethau'n seiliedig ar { -fxaccount-brand-name }, gan gynnwys Sync.
+# Firefox Screenshots is the name of the feature, and should not be translated.
+policy-DisableFirefoxScreenshots = Analluogi nodwedd Firefox Screenshots.
+policy-DisableFirefoxStudies = Rhwystro { -brand-short-name } rhag rhedeg astudiaethau.
+policy-DisableForgetButton = Rhwystro mynediad i'r botwm Anghofio.
+policy-DisableFormHistory = Peidio cofio chwilio a hanes ffurflenni.
+policy-DisableMasterPasswordCreation = Os gwir, nid oes modd creu prif gyfrinair.
+policy-DisablePrimaryPasswordCreation = Os yn wir, nid oes modd creu Prif Cyfrinair.
+policy-DisablePasswordReveal = Peidiwch â gadael i gyfrineiriau gael eu datgelu mewn mewngofnodi sydd wedi'u cadw.
+policy-DisablePocket = Analluogi'r nodwedd i gadw tudalennau gwe i Pocket.
+policy-DisablePrivateBrowsing = Analluogi Pori Preifat.
+policy-DisableProfileImport = Analluogi'r gorchymyn dewislen i fewnforio data o borwr arall.
+policy-DisableProfileRefresh = Analluogi botwm Adnewyddu { -brand-short-name } yn nhudalen about:support
+policy-DisableSafeMode = Analluogi'r nodwedd i ailgychwyn yn y Modd Diogel. Sylw: dim ond drwy'r Polisi Grŵp y mae modd analluogi'r defnydd o fysell Shift i fynd i'r modd Diogel.
+policy-DisableSecurityBypass = Rhwystro'r defnyddiwr rhag osgoi rhai rhybuddion diogelwch.
+policy-DisableSetAsDesktopBackground = Analluogi'r dewislen gorchymyn Gosod fel Delwedd Cefndir ar gyfer delwddau.
+policy-DisableSystemAddonUpdate = Rhwystro'r porwr rhag gosod a diweddaru ychwanegion y system.
+policy-DisableTelemetry = Diffodd Telemetreg
+policy-DisplayBookmarksToolbar = Dangos y Bar Offer Nodau Tudalen drwy ragosodiad.
+policy-DisplayMenuBar = Dangos y Bar Dewislen drwy ragosodiad
+policy-DNSOverHTTPS = Ffurfweddu DNS dros HTTPS.
+policy-DontCheckDefaultBrowser = Analluogi gwirio am y porwr rhagosodedig wrth gychwyn.
+policy-DownloadDirectory = Gosod a chloi'r cyfeiriadur llwytho i lawr.
+# “lock” means that the user won’t be able to change this setting
+policy-EnableTrackingProtection = Galluogi neu analluogi Rhwystro Cynnwys ac o ddewis ei gloi.
+# “lock” means that the user won’t be able to change this setting
+policy-EncryptedMediaExtensions = Galluogi neu Analluogi Estyniadau Cyfryngau Amgryptiedig ac o ddewis eu cloi.
+# A “locked” extension can’t be disabled or removed by the user. This policy
+# takes 3 keys (“Install”, ”Uninstall”, ”Locked”), you can either keep them in
+# English or translate them as verbs.
+policy-Extensions = Gosod, dadosod neu gloi estyniadau. Mae'r dewis gosod yn cymryd URL neu lwybrau fel paramedrau. Mae'r dewisiadau Dadosod a Chloi yn cymryd dynodiad estyniadau.
+policy-ExtensionSettings = Rheoli pob agwedd o osod estyniad.
+policy-ExtensionUpdate = Galluogi neu analluogi diweddaru estyniadau'n awtomatig.
+policy-FirefoxHome = Ffurfweddu Firefox Home.
+policy-FlashPlugin = Caniatáu neu wrthod defnydd o'r ychwanegyn Flash.
+policy-Handlers = Ffurfweddu trinwyr rhaglenni rhagosodedig.
+policy-HardwareAcceleration = Os gau, diffodd cyflymu caledwedd.
+# “lock” means that the user won’t be able to change this setting
+policy-Homepage = Gosod ac o ddewis cloi'r dudalen cartref.
+policy-InstallAddonsPermission = Caniatáu i rai gwefannau i osod ychwanegion
+policy-LegacyProfiles = Analluoga'r nodwedd gan orfodi proffil ar wahân ar gyfer pob gosodiad
+
+## Do not translate "SameSite", it's the name of a cookie attribute.
+
+policy-LegacySameSiteCookieBehaviorEnabled = Galluogi'r gosodiad rhagosodedig ymddygiadol cwci SameSite blaenorol.
+policy-LegacySameSiteCookieBehaviorEnabledForDomainList = Dychwelyd at ymddygiad blaenorol SameSite ar gyfer cwcis ar wefannau penodol.
+
+##
+
+policy-LocalFileLinks = Caniatáu i wefannau penodol gysylltu i ffeiliau lleol.
+policy-ManagedBookmarks = Yn ffurfweddu rhestr o nodau tudalen sy'n cael eu rheoli gan weinyddwr nad yw'r defnyddiwr yn gallu eu newid.
+policy-MasterPassword = Ei gwneud yn ofynnol neu atal defnyddio prif gyfrinair.
+policy-ManualAppUpdateOnly = Caniatáu diweddariadau â llaw yn unig a pheidio â hysbysu'r defnyddiwr am ddiweddariadau.
+policy-PrimaryPassword = Ei gwneud yn ofynnol neu atal defnyddio Prif Gyfrinair.
+policy-NetworkPrediction = Galluogi neu analluoga rhagfynegiad rhwydwaith (rhagosod ymlaen DNS).
+policy-NewTabPage = Galluogi neu analluogi tudalen Tab Newydd.
+policy-NoDefaultBookmarks = Analluogi creu nodau tudalen rhagosodedig wedi eu pecynnu gyda { -brand-short-name }, a'r Nodau Tudalen Clyfar (Ymwelwyd Amlaf, Tagiau Diweddar). Sylw: mae'r polisi hwn ddim ond yn effeithiol os yw'n cael ei ddefnyddio cyn rhedeg y proffil y tro cyntaf.
+policy-OfferToSaveLogins = Gorfodi'r gosodiad i ganiatáu i { -brand-short-name } gynnig cofio mewngofnodion a chyfrineiriau wedi eu cadw. Mae gwerthoedd gwir a gau'n cael eu derbyn.
+policy-OfferToSaveLoginsDefault = Gosodwch y gwerth ragosodedig ar gyfer caniatáu i { -brand-short-name } gynnig cofio mewngofnodion a chyfrineiriau wedi'u cadw. Mae gwerthoedd gwir a ffug yn cael eu derbyn.
+policy-OverrideFirstRunPage = Diystyru y dudalen rhediad gyntaf. Gosod y polisi hwn i gwag os ydych am analluogi'r dudalen rhediad cyntaf.
+policy-OverridePostUpdatePage = Diystyru'r dudalen ôl ddiweddaru "Beth sy'n Newydd". Gosodwch y polisi hwn i gwag os hoffech chi analluogi'r dudalen ôl ddiweddaru.
+policy-PasswordManagerEnabled = Galluogi cadw cyfrineiriau i'r rheolwr cyfrinair.
+# PDF.js and PDF should not be translated
+policy-PDFjs = Analluogwch neu ffurfweddu PDF.js, y darllenydd PDF mewnol yn { -brand-short-name }.
+policy-Permissions2 = Ffurfweddwch y caniatâd ar gyfer camera, meicroffon, lleoliadau, hysbysiadau ac awtochwarae.
+policy-PictureInPicture = Galluogi neu analluogi Llun-mewn-Llun.
+policy-PopupBlocking = Caniatáu rhai gwefannau i ddangos llamlenni drwy ragosodiad.
+policy-Preferences = Gosod a chloi gwerth is-set o ddewisiadau.
+policy-PromptForDownloadLocation = Gofynnwch ble i gadw ffeiliau wrth eu llwytho i lawr.
+policy-Proxy = Ffurfweddu gosodiadau eilydd
+policy-RequestedLocales = Gosodwch y rhestr o locales gofynnol ar gyfer y rhaglen yn ôl eich trefn dewis.
+policy-SanitizeOnShutdown2 = Clirio data llywio wrth gau.
+policy-SearchBar = Gosod y lleoliad ragosodedig y bar chwilio. Mae'r defnyddiwr dal yn cael ei gyfaddasu.
+policy-SearchEngines = Ffurfweddu gosodiadau peiriannau chwilio. Dim ond yn y fersiwn Extended Support Release (ESR) mae'r polisi hwn ar gael.
+policy-SearchSuggestEnabled = Galluogi neu analluogi awgrymiadau chwilio.
+# For more information, see https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/PKCS11/Module_Installation
+policy-SecurityDevices = Gosod modiwlau PKCS #11.
+policy-SSLVersionMax = Gosodwch y fersiwn SSL uchaf.
+policy-SSLVersionMin = Gosodwch y fersiwn SSL lleiaf.
+policy-SupportMenu = Ychwanegu eitem ddewislen cymorth cyfaddas i'r ddewislen cymorth.
+policy-UserMessaging = Peidio â dangos rhai negeseuon i'r defnyddiwr.
+# “format” refers to the format used for the value of this policy.
+policy-WebsiteFilter = Rhwystro gwefannau rhag derbyn ymweliadau. Gw. dogfennaeth am ragor o wybodaeth ar y fformat.
diff --git a/l10n-cy/browser/browser/preferences/addEngine.ftl b/l10n-cy/browser/browser/preferences/addEngine.ftl
new file mode 100644
index 0000000000..7f5d275ea1
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/addEngine.ftl
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+add-engine-window =
+    .title = Ychwanegu Peiriant Chwilio
+    .style = width: 32em;
+add-engine-button = Ychwanegu Peiriant Cyfaddas
+add-engine-name = Enw peiriant chwilio
+add-engine-alias = Enw arall
+add-engine-url = URL y peiriant, defnyddiwch %s yn lle'r term chwilio
+add-engine-cancel =
+    .label = Diddymu
+    .accesskey = D
+add-engine-ok =
+    .label = Ychwanegu Peiriant
+    .accesskey = P
+add-engine-dialog =
+    .buttonlabelaccept = Ychwanegu Peiriant
+    .buttonaccesskeyaccept = P
+engine-name-exists = Mae peiriant o'r enw yna'n bodoli eisoes.
+engine-alias-exists = Mae peiriant o'r enw arall yna'n bodoli eisoes.
diff --git a/l10n-cy/browser/browser/preferences/applicationManager.ftl b/l10n-cy/browser/browser/preferences/applicationManager.ftl
new file mode 100644
index 0000000000..06196cb5b7
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/applicationManager.ftl
@@ -0,0 +1,25 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+app-manager-window =
+    .title = Manylion y rhaglen
+    .style = width: 30em; min-height: 20em;
+
+app-manager-remove =
+    .label = Tynnu
+    .accesskey = T
+
+# Variables:
+#   $type (String) - the URI scheme of the link (e.g. mailto:)
+app-manager-handle-protocol = Mae modd defnyddio'r rhaglenni canlynol i drin { $type } dolen.
+
+# Variables:
+#   $type (String) - the MIME type (e.g. application/binary)
+app-manager-handle-file = Mae modd defnyddio'r rhaglenni canlynol i drin Cynnwys { $type }.
+
+## These strings are followed, on a new line,
+## by the URL or path of the application.
+
+app-manager-web-app-info = Mae'r rhaglen gwe yma wedi ei weini yn:
+app-manager-local-app-info = Mae'r rhaglen wedi ei lleoli yn:
diff --git a/l10n-cy/browser/browser/preferences/blocklists.ftl b/l10n-cy/browser/browser/preferences/blocklists.ftl
new file mode 100644
index 0000000000..707f81cb5a
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/blocklists.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+blocklist-window =
+    .title = Rhestrau Rhwystro
+    .style = width: 55em
+blocklist-description = Dewis y rhestr mae { -brand-short-name } yn ei defnyddio i atal tracio ar-lein. Rhestrau'n cael eu darparu gan <a data-l10n-name="disconnect-link" title="Disconnect"> Datgysylltu</a>.
+blocklist-close-key =
+    .key = w
+blocklist-treehead-list =
+    .label = Rhestr
+blocklist-button-cancel =
+    .label = Diddymu
+    .accesskey = D
+blocklist-button-ok =
+    .label = Cadw Newidiadau
+    .accesskey = N
+blocklist-dialog =
+    .buttonlabelaccept = Cadw Newidiadau
+    .buttonaccesskeyaccept = N
+# This template constructs the name of the block list in the block lists dialog.
+# It combines the list name and description.
+# e.g. "Standard (Recommended). This list does a pretty good job."
+#
+# Variables:
+#   $listName {string, "Standard (Recommended)."} - List name.
+#   $description {string, "This list does a pretty good job."} - Description of the list.
+blocklist-item-list-template = { $listName } { $description }
+blocklist-item-moz-std-listName = Rhestr rhwystro Lefel 1 (Argymell).
+blocklist-item-moz-std-description = Mae'n caniatáu rhai tracwyr fel bod llai o wefannau yn torri.
+blocklist-item-moz-full-listName = Rhestr rhwystro Lefel 2.
+blocklist-item-moz-full-description = Yn rhwystro pob traciwr wedi'u canfod. Efallai na fydd rhai gwefannau neu gynnwys yn llwytho'n iawn.
diff --git a/l10n-cy/browser/browser/preferences/clearSiteData.ftl b/l10n-cy/browser/browser/preferences/clearSiteData.ftl
new file mode 100644
index 0000000000..88222f953d
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/clearSiteData.ftl
@@ -0,0 +1,53 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+clear-site-data-window =
+    .title = Clirio Data
+    .style = width: 35em
+clear-site-data-description = Gall glirio'r oll gwcis a data gwefan wedi eu cadw gan { -brand-short-name } eich allgofnodi o wefannau a thynnu cynnwys all-lein gwe. Ni fydd clirio data storfa dros dro yn effeithio ar eich mewngofnodion.
+clear-site-data-close-key =
+    .key = w
+# The parameters in parentheses in this string describe disk usage
+# in the format ($amount $unit), e.g. "Cookies and Site Data (24 KB)"
+# Variables:
+#   $amount (Number) - Amount of site data currently stored on disk
+#   $unit (String) - Abbreviation of the unit that $amount is in, e.g. "MB"
+clear-site-data-cookies-with-data =
+    .label = Cwcis a Data Gwefan ({ $amount } { $unit })
+    .accesskey = C
+# This string is a placeholder for while the data used to fill
+# clear-site-data-cookies-with-data is loading. This placeholder is usually
+# only shown for a very short time (< 1s), so it should be very similar
+# or the same as clear-site-data-cookies-with-data (except the amount and unit),
+# to avoid flickering.
+clear-site-data-cookies-empty =
+    .label = Cwcis a Data Gwefan
+    .accesskey = C
+clear-site-data-cookies-info = Efallai y cewch eich allgofnodi os fydd wedi ei glirio
+# The parameters in parentheses in this string describe disk usage
+# in the format ($amount $unit), e.g. "Cached Web Content (24 KB)"
+# Variables:
+#   $amount (Number) - Amount of cache currently stored on disk
+#   $unit (String) - Abbreviation of the unit that $amount is in, e.g. "MB"
+clear-site-data-cache-with-data =
+    .label = Cynnwys Gwe wedi'i Storio Dros Dro ({ $amount } { $unit })
+    .accesskey = S
+# This string is a placeholder for while the data used to fill
+# clear-site-data-cache-with-data is loading. This placeholder is usually
+# only shown for a very short time (< 1s), so it should be very similar
+# or the same as clear-site-data-cache-with-data (except the amount and unit),
+# to avoid flickering.
+clear-site-data-cache-empty =
+    .label = Cynnwys Gwe wedi ei Storio Dros Dro
+    .accesskey = S
+clear-site-data-cache-info = Bydd angen i wefannau ail lwytho delweddau a data
+clear-site-data-cancel =
+    .label = Diddymu
+    .accesskey = D
+clear-site-data-clear =
+    .label = Clirio
+    .accesskey = l
+clear-site-data-dialog =
+    .buttonlabelaccept = Clirio
+    .buttonaccesskeyaccept = l
diff --git a/l10n-cy/browser/browser/preferences/colors.ftl b/l10n-cy/browser/browser/preferences/colors.ftl
new file mode 100644
index 0000000000..adf4255142
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/colors.ftl
@@ -0,0 +1,48 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+colors-window =
+    .title = Lliwiau
+    .style =
+        { PLATFORM() ->
+            [macos] width: 41em
+           *[other] width: 38em
+        }
+
+colors-close-key =
+    .key = w
+
+colors-page-override = Anwybyddu'r lliwiau sy'n cael eu pennu gan y dudalen gan ddefnyddio fy newis i uchod
+    .accesskey = A
+
+colors-page-override-option-always =
+    .label = Bob tro
+colors-page-override-option-auto =
+    .label = Dim ond y themâu Cyferbyniad Uchel
+colors-page-override-option-never =
+    .label = Byth
+
+colors-text-and-background = Testun a Chefndir
+
+colors-text-header = Testun
+    .accesskey = T
+
+colors-background = Cefndir
+    .accesskey = C
+
+colors-use-system =
+    .label = Defnyddio lliwiau'r system
+    .accesskey = s
+
+colors-underline-links =
+    .label = Tanlinellu dolenni
+    .accesskey = d
+
+colors-links-header = Lliw Dolenni
+
+colors-unvisited-links = Dolenni heb gael Ymweliad
+    .accesskey = D
+
+colors-visited-links = Dolenni wedi cael Ymweliad
+    .accesskey = w
diff --git a/l10n-cy/browser/browser/preferences/connection.ftl b/l10n-cy/browser/browser/preferences/connection.ftl
new file mode 100644
index 0000000000..4484fad0ff
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/connection.ftl
@@ -0,0 +1,88 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+connection-window =
+    .title = Gosodiadau Cysylltu
+    .style =
+        { PLATFORM() ->
+            [macos] width: 44em
+           *[other] width: 49em
+        }
+connection-close-key =
+    .key = w
+connection-disable-extension =
+    .label = Analluogi Estyniad
+connection-proxy-configure = Ffurfweddu Mynediad Dirprwy i'r Rhyngrwyd
+connection-proxy-option-no =
+    .label = Dim dirprwy
+    .accesskey = D
+connection-proxy-option-system =
+    .label = Defnyddio gosodiadau dirprwyol y system
+    .accesskey = g
+connection-proxy-option-auto =
+    .label = Awto-ganfod gosodiadau dirprwyol ar gyfer y rhwydwaith
+    .accesskey = r
+connection-proxy-option-manual =
+    .label = Ffurfweddiad dirprwyo â llaw
+    .accesskey = l
+connection-proxy-http = Dirprwy yr HTTP
+    .accesskey = H
+connection-proxy-http-port = Porth
+    .accesskey = P
+connection-proxy-http-sharing =
+    .label = Defnyddiwch y dirprwy yma hefyd ar gyfer FTP a HTTPS
+    .accesskey = d
+connection-proxy-https = Dirprwy HTTPS:
+    .accesskey = D
+connection-proxy-ssl-port = Porth
+    .accesskey = o
+connection-proxy-ftp = Dirprwy FTP
+    .accesskey = F
+connection-proxy-ftp-port = Porth
+    .accesskey = r
+connection-proxy-socks = Gwesteiwr SOCKS v5
+    .accesskey = G
+connection-proxy-socks-port = Porth
+    .accesskey = t
+connection-proxy-socks4 =
+    .label = SOCKS v4
+    .accesskey = K
+connection-proxy-socks5 =
+    .label = SOCKS v5
+    .accesskey = v
+connection-proxy-noproxy = Dim Dirprwy ar gyfer
+    .accesskey = m
+connection-proxy-noproxy-desc = Esiampl: .mozilla.org, .net.nz, 192.168.1.0/24
+# Do not translate localhost, 127.0.0.1 and ::1.
+connection-proxy-noproxy-localhost-desc = Nid yw cysylltiadau i localhost, 127.0.0.1, a ::1 byth yn cael eu cirprwyo.
+# Do not translate "localhost", "127.0.0.1/8" and "::1". (You can translate "and".)
+connection-proxy-noproxy-localhost-desc-2 = Nid yw cysylltiadau â localhost, 127.0.0.1/8, a ::1 byth yn cael eu dirprwyo.
+connection-proxy-autotype =
+    .label = URL ffurfweddu dirprwy yn awtomatig
+    .accesskey = U
+connection-proxy-reload =
+    .label = Ail-lwytho
+    .accesskey = i
+connection-proxy-autologin =
+    .label = Peidio gofyn am ddilysiad os yw'r cyfrinair wedi ei gadw
+    .accesskey = d
+    .tooltip = Mae'r dewis hwn yn eich dilysu'n dawel i ddirprwyon rydych wedi eu cadw eu manylion ar eu cyfer. Byddwn yn gofyn os bydd y dilysiad yn methu.
+connection-proxy-socks-remote-dns =
+    .label = DNS dirprwyol wrth ddefnyddio SOCKS v5
+    .accesskey = d
+connection-dns-over-https =
+    .label = Galluogi DNS dros HTTPS
+    .accesskey = D
+connection-dns-over-https-url-resolver = Defnyddio'r Darparwr
+    .accesskey = D
+# Variables:
+#   $name (String) - Display name or URL for the DNS over HTTPS provider
+connection-dns-over-https-url-item-default =
+    .label = { $name } Rhagosodedig
+    .tooltiptext = Defnyddiwch yr URL rhagosodedig i ddatrys DNS dros HTTPS
+connection-dns-over-https-url-custom =
+    .label = Cyfaddasu
+    .accesskey = C
+    .tooltiptext = Rhowch eich hoff URL ar gyfer datrys DNS dros HTTPS
+connection-dns-over-https-custom-label = Cyfaddasu
diff --git a/l10n-cy/browser/browser/preferences/containers.ftl b/l10n-cy/browser/browser/preferences/containers.ftl
new file mode 100644
index 0000000000..30117393c2
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/containers.ftl
@@ -0,0 +1,87 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+containers-window-new =
+    .title = Ychwanegu Cynhwysydd Newydd
+    .style = width: 45em
+# Variables
+#   $name (String) - Name of the container
+containers-window-update =
+    .title = Dewisiadau Cynhwysyddion { $name }
+    .style = width: 45em
+containers-window-close =
+    .key = w
+# This is a term to store style to be applied
+# on the three labels in the containers add/edit dialog:
+#   - name
+#   - icon
+#   - color
+#
+# Using this term and referencing it in the `.style` attribute
+# of the three messages ensures that all three labels
+# will be aligned correctly.
+-containers-labels-style = min-width: 4rem
+containers-name-label = Enw
+    .accesskey = E
+    .style = { -containers-labels-style }
+containers-name-text =
+    .placeholder = Rhowch enw cynhwysydd
+containers-icon-label = Eicon
+    .accesskey = E
+    .style = { -containers-labels-style }
+containers-color-label = Lliw
+    .accesskey = L
+    .style = { -containers-labels-style }
+containers-button-done =
+    .label = Gorffen
+    .accesskey = G
+containers-dialog =
+    .buttonlabelaccept = Gorffen
+    .buttonaccesskeyaccept = G
+containers-color-blue =
+    .label = Glas
+containers-color-turquoise =
+    .label = Glaswyrdd
+containers-color-green =
+    .label = Gwyrdd
+containers-color-yellow =
+    .label = Melyn
+containers-color-orange =
+    .label = Oren
+containers-color-red =
+    .label = Coch
+containers-color-pink =
+    .label = Pinc
+containers-color-purple =
+    .label = Porffor
+containers-color-toolbar =
+    .label = Cydweddu'r bar offer
+containers-icon-fence =
+    .label = Ffens
+containers-icon-fingerprint =
+    .label = Bysbrint
+containers-icon-briefcase =
+    .label = Bag Dogfennau
+# String represents a money sign but currently uses a dollar sign
+# so don't change to local currency. See Bug 1291672.
+containers-icon-dollar =
+    .label = Arwydd dollar
+containers-icon-cart =
+    .label = Cart siopa
+containers-icon-circle =
+    .label = Dot
+containers-icon-vacation =
+    .label = Gwyliau
+containers-icon-gift =
+    .label = Rhodd
+containers-icon-food =
+    .label = Bwyd
+containers-icon-fruit =
+    .label = Ffrwythau
+containers-icon-pet =
+    .label = Anifail Anwes
+containers-icon-tree =
+    .label = Coeden
+containers-icon-chill =
+    .label = Ymlacio
diff --git a/l10n-cy/browser/browser/preferences/fonts.ftl b/l10n-cy/browser/browser/preferences/fonts.ftl
new file mode 100644
index 0000000000..6e673cb9f0
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/fonts.ftl
@@ -0,0 +1,160 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+fonts-window =
+    .title = Ffontiau
+
+fonts-window-close =
+    .key = w
+
+## Font groups by language
+
+fonts-langgroup-header = Ffont ar gyfer
+    .accesskey = F
+
+fonts-langgroup-arabic =
+    .label = Arabaidd
+fonts-langgroup-armenian =
+    .label = Armeneg
+fonts-langgroup-bengali =
+    .label = Bengaleg
+fonts-langgroup-simpl-chinese =
+    .label = Tsieinëeg Syml
+fonts-langgroup-trad-chinese-hk =
+    .label = Tsieinëeg Traddodiadol (Hong Kong)
+fonts-langgroup-trad-chinese =
+    .label = Tsieinëeg Traddodiadol (Taiwan)
+fonts-langgroup-cyrillic =
+    .label = Cyrilig
+fonts-langgroup-devanagari =
+    .label = Devanagari
+fonts-langgroup-ethiopic =
+    .label = Ethiopeg
+fonts-langgroup-georgian =
+    .label = Georgeg
+fonts-langgroup-el =
+    .label = Groeg
+fonts-langgroup-gujarati =
+    .label = Gwjarati
+fonts-langgroup-gurmukhi =
+    .label = Gurmukhi
+fonts-langgroup-japanese =
+    .label = Japanëeg
+fonts-langgroup-hebrew =
+    .label = Hebraeg
+fonts-langgroup-kannada =
+    .label = Kannada
+fonts-langgroup-khmer =
+    .label = Khmer
+fonts-langgroup-korean =
+    .label = Corëeg
+# Translate "Latin" as the name of Latin (Roman) script, not as the name of the Latin language.
+fonts-langgroup-latin =
+    .label = Lladin
+fonts-langgroup-malayalam =
+    .label = Malaialam
+fonts-langgroup-math =
+    .label = Mathemateg
+fonts-langgroup-odia =
+    .label = Odia
+fonts-langgroup-sinhala =
+    .label = Sinhala
+fonts-langgroup-tamil =
+    .label = Tamileg
+fonts-langgroup-telugu =
+    .label = Telugu
+fonts-langgroup-thai =
+    .label = Thai
+fonts-langgroup-tibetan =
+    .label = Tibeteg
+fonts-langgroup-canadian =
+    .label = Unified Canadian Syllabary
+fonts-langgroup-other =
+    .label = Systemau Ysgrifennu Eraill
+
+## Default fonts and their sizes
+
+fonts-proportional-header = Cyfrannol
+    .accesskey = y
+
+fonts-default-serif =
+    .label = Serif
+fonts-default-sans-serif =
+    .label = Sans Serif
+
+fonts-proportional-size = Maint
+    .accesskey = M
+
+fonts-serif = Serif
+    .accesskey = S
+
+fonts-sans-serif = Sans-serif
+    .accesskey = a
+
+fonts-monospace = Monospace
+    .accesskey = o
+
+fonts-monospace-size = Maint
+    .accesskey = a
+
+fonts-minsize = Lleiafswm maint ffont
+    .accesskey = L
+
+fonts-minsize-none =
+    .label = Dim
+
+fonts-allow-own =
+    .label = Caniatáu i dudalennau ddewis eu ffont eu hun, yn lle fy newis i uchod
+    .accesskey = C
+
+## Text Encodings
+##
+## Translate the encoding names as adjectives for an encoding, not as the name
+## of the language.
+
+fonts-languages-fallback-header = Amgodiad Nod ar gyfer Hen Gynnwys
+fonts-languages-fallback-desc = Mae'r amgodiad nod hwn yn cael ei defnyddio ar gyfer hen gynnwys nad yw'n datgan ei amgodiad.
+
+fonts-languages-fallback-label = Amgodiad Testun Eilradd
+    .accesskey = E
+
+fonts-languages-fallback-name-auto =
+    .label = Y Rhagosodedig ar gyfer y Locale Cyfredol
+fonts-languages-fallback-name-arabic =
+    .label = Arabaidd
+fonts-languages-fallback-name-baltic =
+    .label = Baltig
+fonts-languages-fallback-name-ceiso =
+    .label = Canol Ewropeaidd, ISO
+fonts-languages-fallback-name-cewindows =
+    .label = Canol Ewrop, Microsoft
+fonts-languages-fallback-name-simplified =
+    .label = Tsieineeg Symledig
+fonts-languages-fallback-name-traditional =
+    .label = Tsieinëeg Traddodiadol
+fonts-languages-fallback-name-cyrillic =
+    .label = Cyrilig
+fonts-languages-fallback-name-greek =
+    .label = Groeg
+fonts-languages-fallback-name-hebrew =
+    .label = Hebraeg
+fonts-languages-fallback-name-japanese =
+    .label = Japanëeg
+fonts-languages-fallback-name-korean =
+    .label = Corëeg
+fonts-languages-fallback-name-thai =
+    .label = Thai
+fonts-languages-fallback-name-turkish =
+    .label = Twrcaidd
+fonts-languages-fallback-name-vietnamese =
+    .label = Fietnameg
+fonts-languages-fallback-name-other =
+    .label = Eraill (gan gynnwys Gorllewin Ewrop)
+
+# Variables:
+#   $name {string, "Arial"} - Name of the default font
+fonts-label-default =
+    .label = Rhagosodiad ({ $name })
+fonts-label-default-unnamed =
+    .label = Rhagosodiad
diff --git a/l10n-cy/browser/browser/preferences/fxaPairDevice.ftl b/l10n-cy/browser/browser/preferences/fxaPairDevice.ftl
new file mode 100644
index 0000000000..ffff45161a
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/fxaPairDevice.ftl
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+fxa-pair-device-dialog =
+    .title = Cysylltu Dyfais Arall
+    .style = width: 26em; min-height: 35em;
+fxa-qrcode-heading-phase1 = 1. Os nad ydych chi wedi gwneud eisoes, gosodwch <a data-l10n-name="connect-another-device"> Firefox ar eich dyfais symudol </a>.
+fxa-qrcode-heading-phase2 = 2. Yna, mewngofnodwch i { -sync-brand-short-name }, neu ar Android sganio'r cod paru o fewn  gosodiadau { -sync-brand-short-name }.
+fxa-qrcode-heading-step1 = 1. Os nad ydych chi wedi gwneud eisoes, gosodwch <a data-l10n-name="connect-another-device"> Firefox ar eich dyfais symudol </a>.
+fxa-qrcode-heading-step2 = 2. Agor Firefox ar eich dyfais symudol.
+fxa-qrcode-heading-step3 = 3. Agorwch y <b>ddewislen</b> (<img data-l10n-name = "ios-menu-icon" /> neu <img data-l10n-name = "android-menu-icon" />), tapio <img data-l10n-name = "settings-icon" /> <b>Gosodiadau</b> a dewis <b>Cychwyn Sync</b>
+fxa-qrcode-heading-step4 = Sganiwch y cod
+fxa-qrcode-error-title = Paru'n aflwyddiannus.
+fxa-qrcode-error-body = Ceisiwch eto
diff --git a/l10n-cy/browser/browser/preferences/languages.ftl b/l10n-cy/browser/browser/preferences/languages.ftl
new file mode 100644
index 0000000000..04d96d9ae1
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/languages.ftl
@@ -0,0 +1,73 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+webpage-languages-window =
+    .title = Gosodiadau Iaith Tudalen Gwe
+    .style = width: 40em
+
+languages-close-key =
+    .key = w
+
+languages-description = Mae tudalennau gwe weithiau'n cael eu cynnig mewn mwy nag un iaith. Dewiswch ieithoedd i'w harddangos, yn nhrefn dewis
+
+languages-customize-spoof-english =
+    .label = Gofyn am fersiwn Saesneg o dudalennau gwe yn y gobaith o well preifatrwydd
+
+languages-customize-moveup =
+    .label = Symud i Fyny
+    .accesskey = F
+
+languages-customize-movedown =
+    .label = Symud i Lawr
+    .accesskey = L
+
+languages-customize-remove =
+    .label = Tynnu
+    .accesskey = T
+
+languages-customize-select-language =
+    .placeholder = Dewis iaith i'w hychwanegu…
+
+languages-customize-add =
+    .label = Ychwanegu
+    .accesskey = Y
+
+# The pattern used to generate strings presented to the user in the
+# locale selection list.
+#
+# Example:
+#   Icelandic [is]
+#   Spanish (Chile) [es-CL]
+#
+# Variables:
+#   $locale (String) - A name of the locale (for example: "Icelandic", "Spanish (Chile)")
+#   $code (String) - Locale code of the locale (for example: "is", "es-CL")
+languages-code-format =
+    .label = { $locale }  [{ $code }]
+
+languages-active-code-format =
+    .value = { languages-code-format.label }
+
+browser-languages-window =
+    .title = { -brand-short-name } Gosodiadau Iaith
+    .style = width: 40em
+
+browser-languages-description = Bydd { -brand-short-name } yn dangos yr iaith gyntaf fel eich rhagosodedig a bydd yn danogs ieithoedd eraill yn y drefn fyddan nhw'n ymddangos.
+
+browser-languages-search = Chwilio am ragor o ieithoedd…
+
+browser-languages-searching =
+    .label = Chwilio am ieithoedd…
+
+browser-languages-downloading =
+    .label = Llwytho i lawr…
+
+browser-languages-select-language =
+    .label = Dewis iaith i'w gosod…
+    .placeholder = Dewis iaith i'w gosod…
+
+browser-languages-installed-label = Ieithoedd wedi eu gosod
+browser-languages-available-label = Ieithoedd ar gael
+
+browser-languages-error = Nid yw { -brand-short-name } yn gallu diweddaru eich iaith ar hyn o bryd. Gwiriwch eich bod wedi eich cysylltu i'r rhyngrwyd neu ceisiwch eto.
diff --git a/l10n-cy/browser/browser/preferences/permissions.ftl b/l10n-cy/browser/browser/preferences/permissions.ftl
new file mode 100644
index 0000000000..778584f4af
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/permissions.ftl
@@ -0,0 +1,157 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+permissions-window =
+    .title = Eithriadau
+    .style = width: 45em
+permissions-close-key =
+    .key = w
+permissions-address = Cyfeiriad y wefan
+    .accesskey = y
+permissions-block =
+    .label = Rhwystro
+    .accesskey = R
+permissions-session =
+    .label = Caniatáu ar gyfer y Sesiwn
+    .accesskey = S
+permissions-allow =
+    .label = Caniatáu
+    .accesskey = a
+permissions-site-name =
+    .label = Gwefan
+permissions-status =
+    .label = Statws
+permissions-remove =
+    .label = Tynnu Gwefan
+    .accesskey = T
+permissions-remove-all =
+    .label = Tynnu Pob Gwefan
+    .accesskey = G
+permissions-button-cancel =
+    .label = Diddymu
+    .accesskey = D
+permissions-button-ok =
+    .label = Cadw Newidiadau
+    .accesskey = N
+permission-dialog =
+    .buttonlabelaccept = Cadw Newidiadau
+    .buttonaccesskeyaccept = N
+permissions-autoplay-menu = Y rhagosodedig am bob gwefan:
+permissions-searchbox =
+    .placeholder = Chwilio'r Wefan
+permissions-capabilities-autoplay-allow =
+    .label = Caniatáu Sain a Fideo
+permissions-capabilities-autoplay-block =
+    .label = Rhwystro Sain
+permissions-capabilities-autoplay-blockall =
+    .label = Rhwystro Sain a Fideo
+permissions-capabilities-allow =
+    .label = Caniatáu
+permissions-capabilities-block =
+    .label = Rhwystro
+permissions-capabilities-prompt =
+    .label = Gofyn bob Tro
+permissions-capabilities-listitem-allow =
+    .value = Caniatáu
+permissions-capabilities-listitem-block =
+    .value = Rhwystro
+permissions-capabilities-listitem-allow-session =
+    .value = Caniatáu ar gyfer y Sesiwn
+
+## Invalid Hostname Dialog
+
+permissions-invalid-uri-title = Rhoddwyd Enw Parth Annilys
+permissions-invalid-uri-label = Rhoi cyfeiriad e-bost dilys
+
+## Exceptions - Tracking Protection
+
+permissions-exceptions-etp-window =
+    .title = Eithriadau ar gyfer Diogelwch Uwch Rhag Tracio
+    .style = { permissions-window.style }
+permissions-exceptions-etp-desc = Rydych wedi diffodd y diogelu ar y gwefannau hyn.
+
+## Exceptions - Cookies
+
+permissions-exceptions-cookie-window =
+    .title = Eithriadau - Cwcis a Data Gwefan
+    .style = { permissions-window.style }
+permissions-exceptions-cookie-desc = Gallwch bennu pa wefannau sy'n cael defnyddio cwcis a data gwefannau, neu beidio.  Teipiwch union gyfeiriad y wefan rydych am ei reoli ac yna clicio Rhwystro, Caniatáu am y Sesiwn neu Caniatáu.
+
+## Exceptions - Pop-ups
+
+permissions-exceptions-popup-window =
+    .title = Gwefannau Caniatawyd - Llamlenni
+    .style = { permissions-window.style }
+permissions-exceptions-popup-desc = Mae modd pennu pa wefannau sy'n cael agor ffenestri llamlen. Teipiwch union gyfeiriad y wefan rydych am ei ganiatáu ac yna clicio Caniatáu.
+
+## Exceptions - Saved Logins
+
+permissions-exceptions-saved-logins-window =
+    .title = Eithriadau - Mewngofnodion wedi eu Cadw
+    .style = { permissions-window.style }
+permissions-exceptions-saved-logins-desc = Ni fydd mewngofnodion i'r gwefannau canlynol yn cael eu cadw
+
+## Exceptions - Add-ons
+
+permissions-exceptions-addons-window =
+    .title = Gwefannau Caniatawyd - Gosod Ychwanegion
+    .style = { permissions-window.style }
+permissions-exceptions-addons-desc = Gallwch enwi pa wefannau sy'n cael gosod ychwanegion. Teipiwch yr union gyfeiriad gwe rydych am ei chaniatáu ac yna clicio Caniatáu.
+
+## Site Permissions - Autoplay
+
+permissions-site-autoplay-window =
+    .title = Gosodiadau - Autochwarae
+    .style = { permissions-window.style }
+permissions-site-autoplay-desc = Gallwch reoli'r gwefannau nad ydynt yn eu dilyn eich gosodiadau awtochwarae rhagosodedig yma.
+
+## Site Permissions - Notifications
+
+permissions-site-notification-window =
+    .title = Gosodiadau - Caniatáu Hysbysiadau
+    .style = { permissions-window.style }
+permissions-site-notification-desc = Mae'r gwefannau canlynol wedi gofyn i gael anfon hysbysiadau atoch. Gallwch bennu pa wefannau sy'n cael anfon hysbysiadau atoch. Gallwch hefyd rwystro ceisiadau newydd sy'n gofyn i ganiatáu hysbysiadau.
+permissions-site-notification-disable-label =
+    .label = Rhwystro ceisiadau newydd i ganiatáu hysbysiadau
+permissions-site-notification-disable-desc = Bydd hyn yn rhwystro unrhyw wefan sydd heb ei rhestru uchod rhag gofyn am ganiatâd i anfon hysbysiadau. Gall rhwystro hysbysiadau dorri nodweddion rhai gwefannau.
+
+## Site Permissions - Location
+
+permissions-site-location-window =
+    .title = Gosodiadau - Caniatáu Hysbysiadau
+    .style = { permissions-window.style }
+permissions-site-location-desc = Mae'r gwefannau canlynol wedi gofyn i gael mynediad i'ch lleoliad. Gallwch bennu pa wefannau sy'n cael mynediad i'ch lleoliad. Gallwch hefyd rwystro ceisiadau newydd sy'n gofyn i gael mynediad at eich lleoliad.
+permissions-site-location-disable-label =
+    .label = Rhwystro ceisiadau newydd sy'n gofyn i gael mynediad i'ch lleoliad
+permissions-site-location-disable-desc = Bydd hyn yn rhwystro unrhyw wefan sydd heb ei rhestru uchod rhag gofyn am ganiatâd i gael mynediad i'ch lleoliad. Gall rhwystro mynediad i'ch lleoliad dorri nodweddion rhai gwefannau.
+
+## Site Permissions - Virtual Reality
+
+permissions-site-xr-window =
+    .title = Gosodiadau - Caniatâd Rhithrealaeth
+    .style = { permissions-window.style }
+permissions-site-xr-desc = Mae'r gwefannau canlynol wedi gofyn am gael mynediad i'ch dyfeisiau rhithrealaeth. Gallwch chi nodi pa wefannau sy'n cael mynediad i'ch dyfeisiau rhithrealaeth. Gallwch hefyd rwystro ceisiadau newydd sy'n gofyn am gael mynediad i'ch dyfeisiau rhithrealaeth .
+permissions-site-xr-disable-label =
+    .label = Rhwystro geisiadau newydd sy'n gofyn am gael mynediad i'ch dyfeisiau rhithrealaeth
+permissions-site-xr-disable-desc = Bydd hyn yn rhwystro unrhyw wefan sydd heb ei rhestru uchod rhag gofyn am ganiatâd i gael mynediad i'ch dyfeisiau rhithrealaeth. Gall rhwystro mynediad i'ch dyfeisiau rhithrealaeth dorri nodweddion rhai gwefannau.
+
+## Site Permissions - Camera
+
+permissions-site-camera-window =
+    .title = Gosodiadau - Caniatâd Camera
+    .style = { permissions-window.style }
+permissions-site-camera-desc = Mae'r gwefannau canlynol wedi gofyn i gael mynediad i'ch camera. Gallwch bennu pa wefannau sy'n cael mynediad i'ch camera. Gallwch hefyd rwystro ceisiadau newydd sy'n gofyn i gael mynediad at eich camera.
+permissions-site-camera-disable-label =
+    .label = Rhwystro ceisiadau newydd sy'n gofyn i gael mynediad i'ch camera
+permissions-site-camera-disable-desc = Bydd hyn yn rhwystro unrhyw wefan sydd heb ei rhestru uchod rhag gofyn am ganiatâd i gael mynediad i'ch camera. Gall rhwystro mynediad i'ch camera dorri nodweddion rhai gwefannau.
+
+## Site Permissions - Microphone
+
+permissions-site-microphone-window =
+    .title = Gosodiadau - Caniatâd Meicroffon
+    .style = { permissions-window.style }
+permissions-site-microphone-desc = Mae'r gwefannau canlynol wedi gofyn i gael mynediad i'ch meicroffon. Gallwch bennu pa wefannau sy'n cael mynediad i'ch meicroffon. Gallwch hefyd rwystro ceisiadau newydd sy'n gofyn i gael mynediad at eich meicroffon.
+permissions-site-microphone-disable-label =
+    .label = Rhwystro ceisiadau newydd sy'n gofyn i gael mynediad i'ch meicroffon
+permissions-site-microphone-disable-desc = Bydd hyn yn rhwystro unrhyw wefan sydd heb ei rhestru uchod rhag gofyn am ganiatâd i gael mynediad i'ch meicroffon. Gall rhwystro mynediad i'ch meicroffon dorri nodweddion rhai gwefannau.
diff --git a/l10n-cy/browser/browser/preferences/preferences.ftl b/l10n-cy/browser/browser/preferences/preferences.ftl
new file mode 100644
index 0000000000..2818615e44
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/preferences.ftl
@@ -0,0 +1,1193 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+do-not-track-description = Anfon neges “Dim Tracio” at wefannau nad ydych am gael eich tracio
+do-not-track-learn-more = Dysgu rhagor
+do-not-track-option-default-content-blocking-known =
+    .label = Dim ond pan mae { -brand-short-name } wedi ei osod i rwystro tracwyr hysbys.
+do-not-track-option-always =
+    .label = Bob tro
+pref-page-title =
+    { PLATFORM() ->
+        [windows] Opsiynau
+       *[other] Dewisiadau
+    }
+# This is used to determine the width of the search field in about:preferences,
+# in order to make the entire placeholder string visible
+#
+# Please keep the placeholder string short to avoid truncation.
+#
+# Notice: The value of the `.style` attribute is a CSS string, and the `width`
+# is the name of the CSS property. It is intended only to adjust the element's width.
+# Do not translate.
+search-input-box =
+    .style = width: 15.4em
+    .placeholder =
+        { PLATFORM() ->
+            [windows] Canfod yn Opsiynau
+           *[other] Canfod yn Dewisiadau
+        }
+managed-notice = Mae eich porwr yn cael ei reoli gan eich sefydliad.
+category-list =
+    .aria-label = Categorïau
+pane-general-title = Cyffredinol
+category-general =
+    .tooltiptext = { pane-general-title }
+pane-home-title = Cartref
+category-home =
+    .tooltiptext = { pane-home-title }
+pane-search-title = Chwilio
+category-search =
+    .tooltiptext = { pane-search-title }
+pane-privacy-title = Preifatrwydd a Diogelwch
+category-privacy =
+    .tooltiptext = { pane-privacy-title }
+pane-sync-title2 = { -sync-brand-short-name }
+category-sync2 =
+    .tooltiptext = { pane-sync-title2 }
+pane-experimental-title = Arbrofion { -brand-short-name }
+category-experimental =
+    .tooltiptext = Arbrofion { -brand-short-name }
+pane-experimental-subtitle = Gofal!
+pane-experimental-search-results-header = Arbrofion { -brand-short-name }: Byddwch yn Ofalus
+pane-experimental-description = Gall newid dewisiadau ffurfweddiad uwch effeithio ar berfformiad neu ddiogelwch { -brand-short-name }.
+pane-experimental-reset =
+    .label = Adfer y Rhagosodiadau
+    .accesskey = A
+help-button-label = Cefnogaeth { -brand-short-name }
+addons-button-label = Estyniadau a Themâu
+focus-search =
+    .key = f
+close-button =
+    .aria-label = Cau
+
+## Browser Restart Dialog
+
+feature-enable-requires-restart = Rhaid ailgychwyn { -brand-short-name } i alluogi'r nodwedd hon.
+feature-disable-requires-restart = Rhaid ailgychwyn { -brand-short-name } i analluogi'r nodwedd hon.
+should-restart-title = Ailgychwyn { -brand-short-name }
+should-restart-ok = Ailgychwynnwch { -brand-short-name } nawr
+cancel-no-restart-button = Diddymu
+restart-later = Ailgychwyn Rhywbryd Eto
+
+## Extension Control Notifications
+##
+## These strings are used to inform the user
+## about changes made by extensions to browser settings.
+##
+## <img data-l10n-name="icon"/> is going to be replaced by the extension icon.
+##
+## Variables:
+##   $name (String): name of the extension
+
+# This string is shown to notify the user that their home page
+# is being controlled by an extension.
+extension-controlled-homepage-override = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli eich tudalen cartref.
+# This string is shown to notify the user that their new tab page
+# is being controlled by an extension.
+extension-controlled-new-tab-url = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli eich tudalen Tab Newydd.
+# This string is shown to notify the user that the password manager setting
+# is being controlled by an extension
+extension-controlled-password-saving = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli'r gosodiad hwn.
+# This string is shown to notify the user that their notifications permission
+# is being controlled by an extension.
+extension-controlled-web-notifications = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli'r gosodiad hwn.
+# This string is shown to notify the user that the default search engine
+# is being controlled by an extension.
+extension-controlled-default-search = Mae'r estyniad <img data-l10n-name="icon"/> { $name }, wedi gosod eich peiriant chwilio ragosodedig.
+# This string is shown to notify the user that Container Tabs
+# are being enabled by an extension.
+extension-controlled-privacy-containers = Mae estyniad <img data-l10n-name="icon"/> { $name }, angen Tabiau Cynhwysydd.
+# This string is shown to notify the user that their content blocking "All Detected Trackers"
+# preferences are being controlled by an extension.
+extension-controlled-websites-content-blocking-all-trackers = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli'r gosodiad hwn.
+# This string is shown to notify the user that their proxy configuration preferences
+# are being controlled by an extension.
+extension-controlled-proxy-config = Mae estyniad <img data-l10n-name="icon"/> { $name }, yn rheoli sut mae { -brand-short-name } yn cysylltu â'r rhyngrwyd.
+# This string is shown after the user disables an extension to notify the user
+# how to enable an extension that they disabled.
+#
+# <img data-l10n-name="addons-icon"/> will be replaced with Add-ons icon
+# <img data-l10n-name="menu-icon"/> will be replaced with Menu icon
+extension-controlled-enable = I alluogi'r estyniad ewch i Ychwanegion <img data-l10n-name="addons-icon"/> yn y ddewislen <img data-l10n-name="menu-icon"/>.
+
+## Preferences UI Search Results
+
+search-results-header = Canlyniadau Chwilio
+# `<span data-l10n-name="query"></span>` will be replaced by the search term.
+search-results-empty-message =
+    { PLATFORM() ->
+        [windows] Ymddiheuriadau! Nid oes canlyniadau yn yr Opsiynau ar gyfer “<span data-l10n-name="query"></span>”.
+       *[other] Ymddiheuriadau! Nid os canlyniadau yn y Dewisiada.u ar gyfer “<span data-l10n-name="query"></span>”.
+    }
+search-results-help-link = Angen help? Ewch i <a data-l10n-name="url">Cefnogaeth { -brand-short-name }</a>
+
+## General Section
+
+startup-header = Cychwyn
+# { -brand-short-name } will be 'Firefox Developer Edition',
+# since this setting is only exposed in Firefox Developer Edition
+separate-profile-mode =
+    .label = Caniatáu i { -brand-short-name } a Firefox redeg ar yr un pryd
+use-firefox-sync = Cyngor: Mae'n defnyddio proffiliau gwahanol. Defnyddiwch { -sync-brand-short-name } i rannu data rhyngddynt.
+get-started-not-logged-in = Mewngofnodi i { -sync-brand-short-name }…
+get-started-configured = Agor dewisiadau { -sync-brand-short-name }
+always-check-default =
+    .label = Wrth gychwyn, gwirio ai { -brand-short-name } yw eich porwr ragosodedig
+    .accesskey = W
+is-default = { -brand-short-name } yw eich porwr rhagosodedig cyfredol
+is-not-default = { -brand-short-name } yw eich porwr rhagosodedig cyfredol
+set-as-my-default-browser =
+    .label = Gwneud yn Ragosodedig…
+    .accesskey = R
+startup-restore-previous-session =
+    .label = Adfer y sesiwn flaenorol
+    .accesskey = A
+startup-restore-warn-on-quit =
+    .label = Rhybuddio wrth adael y porwr
+disable-extension =
+    .label = Analluogi Estyniad
+tabs-group-header = Tabiau
+ctrl-tab-recently-used-order =
+    .label = Mae Ctrl+Tab yn cylchdroi drwy dabiau yn y drefn y'u defnyddiwyd yn ddiweddar
+    .accesskey = T
+open-new-link-as-tabs =
+    .label = Agor dolenni mewn tabiau ac nid mewn ffenestri newydd
+    .accesskey = f
+warn-on-close-multiple-tabs =
+    .label = Rhybuddio wrth gau mwy nag un tab
+    .accesskey = g
+warn-on-open-many-tabs =
+    .label = Rhybuddio y gall agor mwy nag un tab arafu { -brand-short-name }
+    .accesskey = a
+switch-links-to-new-tabs =
+    .label = Wrth agor dolen mewn tab newydd, symud yn syth iddo
+    .accesskey = W
+show-tabs-in-taskbar =
+    .label = Dangos rhagolwg tab ym mar tasgau Windows
+    .accesskey = D
+browser-containers-enabled =
+    .label = Galluogi Tabiau Cynwysyddion
+    .accesskey = G
+browser-containers-learn-more = Dysgu rhagor
+browser-containers-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+containers-disable-alert-title = Cau Tabiau Pob Cynhwysydd?
+containers-disable-alert-desc =
+    { $tabCount ->
+        [zero] Os fyddwch yn analluogi'r Tabiau Cynhwysydd, nid fydd tabiau cynhwysydd yn cael eu cau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+        [one] Os fyddwch yn analluogi Tabiau Cynhwysyddion nawr, bydd { $tabCount } cynhwysydd tabiau yn cael ei gau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+        [two] Os fyddwch yn analluogi Tabiau Cynhwysyddion nawr, bydd { $tabCount } gynhwysydd tabiau yn cael eu cau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+        [few] Os fyddwch yn analluogi Tabiau Cynhwysyddion nawr, bydd { $tabCount } chynhwysydd tabiau yn cael eu cau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+        [many] Os fyddwch yn analluogi Tabiau Cynhwysyddion nawr, bydd { $tabCount } cynhwysydd tabiau yn cael eu cau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+       *[other] Os fyddwch yn analluogi Tabiau Cynhwysyddion nawr, bydd { $tabCount } cynhwysydd tabiau yn cael eu cau. Ydych chi'n siŵr eich bod am analluogi Tabiau Cynhwysyddion?
+    }
+containers-disable-alert-ok-button =
+    { $tabCount ->
+        [zero] Peidio Cau Tabiau Cynhwysydd
+        [one] Cau { $tabCount } Tab Cynhwysydd
+        [two] Cau { $tabCount } Dab Cynhwysydd
+        [few] Cau { $tabCount } Thab Cynhwysydd
+        [many] Cau { $tabCount } Thab Cynhwysydd
+       *[other] Cau { $tabCount } Tab Cynhwysydd
+    }
+containers-disable-alert-cancel-button = Cadw wedi ei alluogi
+containers-remove-alert-title = Tynnu'r Cynhwysydd Hwn?
+# Variables:
+#   $count (Number) - Number of tabs that will be closed.
+containers-remove-alert-msg =
+    { $count ->
+        [zero] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, ni fydd tabiau yn cael eu cau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+        [one] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, bydd { $count } tab yn cael ei gau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+        [two] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, bydd { $count } dab yn cael eu cau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+        [few] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, bydd { $count } thab yn cael eu cau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+        [many] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, bydd { $count } thab yn cael eu cau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+       *[other] Os fyddwch yn tynnu'r cynhwysydd hwn nawr, bydd { $count } tab yn cael eu cau. Ydych chi'n siŵr eich bod am dynnu'r Cynhwysydd hwn?
+    }
+containers-remove-ok-button = Tynnu'r Cynhwysydd Hwn
+containers-remove-cancel-button = Peidio Tynnu'r Cynhwysydd Hwn
+
+## General Section - Language & Appearance
+
+language-and-appearance-header = Iaith a Gwedd
+fonts-and-colors-header = Ffontiau a Lliwiau
+default-font = Ffont rhagosodedig:
+    .accesskey = F
+default-font-size = Maint:
+    .accesskey = M
+advanced-fonts =
+    .label = Uwch…
+    .accesskey = w
+colors-settings =
+    .label = Lliwiau…
+    .accesskey = i
+# Zoom is a noun, and the message is used as header for a group of options
+preferences-zoom-header = Chwyddo
+preferences-default-zoom = Chwyddo rhagosodedig
+    .accesskey = C
+preferences-default-zoom-value =
+    .label = { $percentage }%
+preferences-zoom-text-only =
+    .label = Chwyddo testun yn unig
+    .accesskey = t
+language-header = Iaith
+choose-language-description = Dewis eich dewis iaith i ddangos tudalennau
+choose-button =
+    .label = Dewis…
+    .accesskey = D
+choose-browser-language-description = Dewiswch yr iaith i ddangos dewislenni, negeseuon a hysbysiadau gan { -brand-short-name }
+manage-browser-languages-button =
+    .label = Gosod Rhai Eraill
+    .accesskey = G
+confirm-browser-language-change-description = Ailgychwyn { -brand-short-name } i osod y newidiadau hyn
+confirm-browser-language-change-button = Gosod ac Ailgychwyn
+translate-web-pages =
+    .label = Cyfieithu cynnwys gwe
+    .accesskey = C
+# The <img> element is replaced by the logo of the provider
+# used to provide machine translations for web pages.
+translate-attribution = Cyfieithiadau gan <img data-l10n-name="logo"/>
+translate-exceptions =
+    .label = Eithriadau…
+    .accesskey = i
+# Variables:
+#    $localeName (string) - Localized name of the locale to be used.
+use-system-locale =
+    .label = Defnyddiwch osodiadau eich system weithredu ar gyfer “{ $localeName }” i fformatio dyddiadau, amseroedd, rhifau a mesuriadau.
+check-user-spelling =
+    .label = Gwirio'r sillafu wrth deipio
+    .accesskey = G
+
+## General Section - Files and Applications
+
+files-and-applications-title = Ffeiliau a Rhaglenni
+download-header = Llwytho i Lawr
+download-save-to =
+    .label = Cadw ffeiliau yn
+    .accesskey = a
+download-choose-folder =
+    .label =
+        { PLATFORM() ->
+            [macos] Dewis…
+           *[other] Pori…
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [macos] D
+           *[other] P
+        }
+download-always-ask-where =
+    .label = Gofyn i mi lle i gadw ffeiliau
+    .accesskey = G
+applications-header = Rhaglenni
+applications-description = Dewis sut mae { -brand-short-name } yn trin y ffeiliau rydych wedi eu llwytho i lawr o'r We neu'r rhaglenni rydych yn eu defnyddio wrth bori.
+applications-filter =
+    .placeholder = Chwilio'r mathau o ffeil neu raglenni
+applications-type-column =
+    .label = Math o Gynnwys
+    .accesskey = M
+applications-action-column =
+    .label = Gweithred
+    .accesskey = G
+# Variables:
+#   $extension (String) - file extension (e.g .TXT)
+applications-file-ending = Ffeil { $extension }
+applications-action-save =
+    .label = Cadw Ffeil
+# Variables:
+#   $app-name (String) - Name of an application (e.g Adobe Acrobat)
+applications-use-app =
+    .label = Defnyddio { $app-name }
+# Variables:
+#   $app-name (String) - Name of an application (e.g Adobe Acrobat)
+applications-use-app-default =
+    .label = Defnyddio { $app-name } (rhagosodiad)
+applications-use-os-default =
+    .label =
+        { PLATFORM() ->
+            [macos] Defnyddiwch raglen ragosodedig macOS
+            [windows] Defnyddiwch raglen ragosodedig Windows
+           *[other] Defnyddiwch raglen ragosodedig y system
+        }
+applications-use-other =
+    .label = Defnyddio arall…
+applications-select-helper = Dewis Rhaglen Gynorthwyol
+applications-manage-app =
+    .label = Manylion y Rhaglen…
+applications-always-ask =
+    .label = Gofyn bob tro
+applications-type-pdf = Portable Document Format (PDF)
+# Variables:
+#   $type (String) - the MIME type (e.g application/binary)
+applications-type-pdf-with-type = { applications-type-pdf } ({ $type })
+# Variables:
+#   $type-description (String) - Description of the type (e.g "Portable Document Format")
+#   $type (String) - the MIME type (e.g application/binary)
+applications-type-description-with-type = { $type-description } ({ $type })
+# Variables:
+#   $extension (String) - file extension (e.g .TXT)
+#   $type (String) - the MIME type (e.g application/binary)
+applications-file-ending-with-type = { applications-file-ending } ({ $type })
+# Variables:
+#   $plugin-name (String) - Name of a plugin (e.g Adobe Flash)
+applications-use-plugin-in =
+    .label = Defnyddio { $plugin-name } (yn { -brand-short-name })
+applications-open-inapp =
+    .label = Agorwch yn { -brand-short-name }
+
+## The strings in this group are used to populate
+## selected label element based on the string from
+## the selected menu item.
+
+applications-use-plugin-in-label =
+    .value = { applications-use-plugin-in.label }
+applications-action-save-label =
+    .value = { applications-action-save.label }
+applications-use-app-label =
+    .value = { applications-use-app.label }
+applications-open-inapp-label =
+    .value = { applications-open-inapp.label }
+applications-always-ask-label =
+    .value = { applications-always-ask.label }
+applications-use-app-default-label =
+    .value = { applications-use-app-default.label }
+applications-use-other-label =
+    .value = { applications-use-other.label }
+applications-use-os-default-label =
+    .value = { applications-use-os-default.label }
+
+##
+
+drm-content-header = Cynnwys Rheoli Hawliau Digidol (DRM)
+play-drm-content =
+    .label = Chwarae cynnwys wedi ei reoli gan DRM
+    .accesskey = C
+play-drm-content-learn-more = Dysgu rhagor
+update-application-title = Diweddariadau { -brand-short-name }
+update-application-description = Cadw { -brand-short-name } yn gyfredol am y perfformiad, y sefydlogrwydd a'r diogelwch gorau.
+update-application-version = Fersiwn { $version } <a data-l10n-name="learn-more">Beth sy'n newydd</a>
+update-history =
+    .label = Dangos Hanes Diweddaru…
+    .accesskey = D
+update-application-allow-description = Caniatáu i { -brand-short-name }
+update-application-auto =
+    .label = Gosod diweddariadau'n awtomatig (argymell)
+    .accesskey = G
+update-application-check-choose =
+    .label = Gwirio am ddiweddariadau, ond gadael i mi ddewis i'w gosod a'i peidio
+    .accesskey = G
+update-application-manual =
+    .label = Byth gwirio am ddiweddariadau (ddim yn argymell)
+    .accesskey = B
+update-application-warning-cross-user-setting = Bydd y gosodiad hwn yn berthnasol i bob cyfrif Windows a proffiliau { -brand-short-name } sy'n ddefnyddio'r gosodiad { -brand-short-name } hwn.
+update-application-use-service =
+    .label = Defnyddio gwasanaethau cefndirol i osod diweddariadau
+    .accesskey = c
+update-setting-write-failure-title = Gwall wrth gadw dewisiadau Diweddaru
+# Variables:
+#   $path (String) - Path to the configuration file
+# The newlines between the main text and the line containing the path is
+# intentional so the path is easier to identify.
+update-setting-write-failure-message =
+    Bu gwall ar { -brand-short-name } ac nid yw wedi cadw'r newid hwn. Noder bod gosod caniatâd ar gyfer y diweddariad hwn yn gofyn am ganiatâd i ysgrifennu at y ffeil isod. Efallai y byddwch chi neu weinyddwr system yn gallu datrys y gwall trwy roi rheolaeth lawn i'r ffeil hon i'r grŵp Defnyddwyr.
+    
+    Doedd dim modd ysgrifennu i ffeil: { $path }
+update-in-progress-title = Wrthi'n Diweddaru
+update-in-progress-message = Hoffech chi i { -brand-short-name } barhau gyda'r diweddariad hwn?
+update-in-progress-ok-button = &Dileu
+# Continue is the cancel button so pressing escape or using a platform standard
+# method of closing the UI will not discard the update.
+update-in-progress-cancel-button = &Parhau
+
+## General Section - Performance
+
+performance-title = Perfformiad
+performance-use-recommended-settings-checkbox =
+    .label = Defnyddio'r gosodiadau perfformiad sy'n cael eu hargymell
+    .accesskey = D
+performance-use-recommended-settings-desc = Mae'r gosodiadau hyn wedi eu teilwrio i galedwedd a system weithredu eich cyfrifiadur.
+performance-settings-learn-more = Dysgu rhagor
+performance-allow-hw-accel =
+    .label = Defnyddio cyflymu caledwedd pan fydd ar gael
+    .accesskey = e
+performance-limit-content-process-option = Terfyn proses cynnwys
+    .accesskey = T
+performance-limit-content-process-enabled-desc = Mae rhagor o brosesau cynnwys yn gallu gwella perfformiad pan yn defnyddio tabiau lluosog, ond fydd hefyd yn defnyddio mwy o gof.
+performance-limit-content-process-blocked-desc = Dim ond yn y fersiwn amlbroses o { -brand-short-name } y mae newid y nifer o brosesau cynnwys yn bosib. <a data-l10n-name="learn-more">Dysgwch sut i weld os yw aml-brosesu wedi ei alluogi</a>
+# Variables:
+#   $num - default value of the `dom.ipc.processCount` pref.
+performance-default-content-process-count =
+    .label = { $num } (rhagosodiad)
+
+## General Section - Browsing
+
+browsing-title = Pori
+browsing-use-autoscroll =
+    .label = Defnyddio awto sgrolio
+    .accesskey = a
+browsing-use-smooth-scrolling =
+    .label = Defnyddio sgrolio llyfn
+    .accesskey = s
+browsing-use-onscreen-keyboard =
+    .label = Dangos bysellfwrdd cyffwrdd pan fydd angen
+    .accesskey = b
+browsing-use-cursor-navigation =
+    .label = Defnyddio bysellau'r cyrchwr ar gyfer symud o fewn tudalennau
+    .accesskey = D
+browsing-search-on-start-typing =
+    .label = Chwilio am destun wrth i mi gychwyn teipio
+    .accesskey = d
+browsing-picture-in-picture-toggle-enabled =
+    .label = Galluogi rheolyddion fideo Llun mewn Llun
+    .accesskey = G
+browsing-picture-in-picture-learn-more = Dysgu rhagor
+browsing-media-control =
+    .label = Rheoli cyfryngau trwy fysellfwrdd, penset neu ryngwyneb rhithwir
+    .accesskey = t
+browsing-media-control-learn-more = Dysgu rhagor
+browsing-cfr-recommendations =
+    .label = Argymell estyniadau wrth i chi bori
+    .accesskey = A
+browsing-cfr-features =
+    .label = Argymell nodweddion wrth bori
+    .accesskey = A
+browsing-cfr-recommendations-learn-more = Dysgu Rhagor
+
+## General Section - Proxy
+
+network-settings-title = Gosodiadau Rhwydwaith
+network-proxy-connection-description = Ffurfweddu sut mae { -brand-short-name } yn cysylltu â'r rhyngrwyd.
+network-proxy-connection-learn-more = Dysgu rhagor
+network-proxy-connection-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+
+## Home Section
+
+home-new-windows-tabs-header = Ffenestri a Thabiau Newydd
+home-new-windows-tabs-description2 = Dewis beth fyddwch yn ei weld wrth i chi agor eich tudalen cartref, ffenestri newydd a thabiau newydd.
+
+## Home Section - Home Page Customization
+
+home-homepage-mode-label = Tudalen cartref a ffenestri newydd
+home-newtabs-mode-label = Tabiau newydd
+home-restore-defaults =
+    .label = Adfer gosodiadau
+    .accesskey = A
+# "Firefox" should be treated as a brand and kept in English,
+# while "Home" and "(Default)" can be localized.
+home-mode-choice-default =
+    .label = Cartref Firefox (Rhagosodiad)
+home-mode-choice-custom =
+    .label = URLau Cyfaddas...
+home-mode-choice-blank =
+    .label = Tudalen Wag
+home-homepage-custom-url =
+    .placeholder = Gludo URL...
+# This string has a special case for '1' and [other] (default). If necessary for
+# your language, you can add {$tabCount} to your translations and use the
+# standard CLDR forms, or only use the form for [other] if both strings should
+# be identical.
+use-current-pages =
+    .label =
+        { $tabCount ->
+            [1] Defnyddio'r Dudalen Bresennol
+           *[other] Defnyddio'r Dudalen Bresennol
+        }
+    .accesskey = B
+choose-bookmark =
+    .label = Defnyddio Nod Tudalen…
+    .accesskey = N
+
+## Home Section - Firefox Home Content Customization
+
+home-prefs-content-header = Cynnwys Cartref Firefox
+home-prefs-content-description = Dewis pa gynnwys rydych eisiau ar eich sgrin Firefox Cartref.
+home-prefs-search-header =
+    .label = Chwilio'r We
+home-prefs-topsites-header =
+    .label = Hoff Wefannau
+home-prefs-topsites-description = Y gwefannau rydych yn ymweld â nhw amlaf
+home-prefs-topsites-by-option-sponsored =
+    .label = Hoff Wefannau Wedi eu Noddi
+home-prefs-shortcuts-header =
+    .label = Llwybrau Byr
+home-prefs-shortcuts-description = Gwefannau rydych yn eu cadw neu'n ymweld â nhw
+home-prefs-shortcuts-by-option-sponsored =
+    .label = Llwybrau byr wedi'u noddi
+
+## Variables:
+##  $provider (String): Name of the corresponding content provider, e.g "Pocket".
+
+home-prefs-recommended-by-header =
+    .label = Argymhellwyd gan { $provider }
+home-prefs-recommended-by-description-update = Cynnwys eithriadol o bob rhan o'r we, wedi'i guradu gan { $provider }
+home-prefs-recommended-by-description-new = Cynnwys eithriadol wedi'u curadu gan { $provider }, rhan o deulu { -brand-product-name }
+
+##
+
+home-prefs-recommended-by-learn-more = Sut mae'n gweithio
+home-prefs-recommended-by-option-sponsored-stories =
+    .label = Straeon wedi eu Noddi
+home-prefs-highlights-header =
+    .label = Goreuon
+home-prefs-highlights-description = Detholiad o wefannau rydych wedi eu cadw neu ymweld â nhw
+home-prefs-highlights-option-visited-pages =
+    .label = Tudalennau Ymwelwyd â Nhw
+home-prefs-highlights-options-bookmarks =
+    .label = Nodau Tudalen
+home-prefs-highlights-option-most-recent-download =
+    .label = Llwytho i Lawr Mwyaf Diweddar
+home-prefs-highlights-option-saved-to-pocket =
+    .label = Tudalennau wedi eu Cadw i { -pocket-brand-name }
+home-prefs-recent-activity-header =
+    .label = Gweithgaredd diweddar
+home-prefs-recent-activity-description = Detholiad o wefannau a chynnwys diweddar
+# For the "Snippets" feature traditionally on about:home.
+# Alternative translation options: "Small Note" or something that
+# expresses the idea of "a small message, shortened from something else,
+# and non-essential but also not entirely trivial and useless.
+home-prefs-snippets-header =
+    .label = Pytiau
+home-prefs-snippets-description = Diweddariadau gan { -vendor-short-name } a { -brand-product-name }
+home-prefs-snippets-description-new = Awgrymiadau a newyddion gan { -vendor-short-name } a { -brand-product-name }
+home-prefs-sections-rows-option =
+    .label =
+        { $num ->
+            [zero] { $num } rhes
+            [one] { $num } rhes
+            [two] { $num } rhes
+            [few] { $num } rhes
+            [many] { $num } rhes
+           *[other] { $num } rhes
+        }
+
+## Search Section
+
+search-bar-header = Bar Chwilio
+search-bar-hidden =
+    .label = Defnyddio'r bar cyfeiriadau ar gyfer chwilio a llywio
+search-bar-shown =
+    .label = Ychwanegu'r bar chwilio i'r bar offer
+search-engine-default-header = Peiriant Chwilio Rhagosodedig
+search-engine-default-desc-2 = Hwn yw'ch peiriant chwilio rhagosodedig yn y bar cyfeiriad a'r bar chwilio. Gallwch ei newid ar unrhyw adeg.
+search-engine-default-private-desc-2 = Dewiswch beiriant chwilio rhagosodedig i'w ddefnyddio yn y Ffenestr Breifat yn unig.
+search-separate-default-engine =
+    .label = Defnyddio'r peiriant chwilio hwn mewn Ffenestri Preifat
+    .accesskey = D
+search-suggestions-header = Awgrymiadau Chwilio
+search-suggestions-desc = Dewis sut mae awgrymiadau gan beiriannau chwilio yn ymddangos.
+search-suggestions-option =
+    .label = Darparu awgrymiadau chwilio
+    .accesskey = c
+search-show-suggestions-url-bar-option =
+    .label = Dangos awgrymiadau chwilio yng nghanlyniadau'r bar lleoliad
+    .accesskey = D
+# This string describes what the user will observe when the system
+# prioritizes search suggestions over browsing history in the results
+# that extend down from the address bar. In the original English string,
+# "ahead" refers to location (appearing most proximate to), not time
+# (appearing before).
+search-show-suggestions-above-history-option =
+    .label = Dangos awgrymiadau chwilio o flaen hanes yng nghanlyniadau'r bar cyfeiriadau
+search-show-suggestions-private-windows =
+    .label = Dangos awgrymiadau chwilio mewn Ffenestri Preifat
+suggestions-addressbar-settings-generic = Newid dewisiadau awgrymiadau eraill y bar cyfeiriad
+search-suggestions-cant-show = Ni fydd awgrymiadau chwilio'n cael eu dangos yn y bar lleoliad gan eich bod wedi ffurfweddu { -brand-short-name } i byth cofio hanes.
+search-one-click-header = Peiriannau Chwilio Un Clic
+search-one-click-header2 = Chwilio'r Llwybrau Byr
+search-one-click-desc = Dewis peiriant chwilio arall sy'n ymddangos o dan y bar cyfeiriad a'r bar chwilio pan fyddwch yn cychwyn allweddair.
+search-choose-engine-column =
+    .label = Peiriannau Chwilio
+search-choose-keyword-column =
+    .label = Allweddair
+search-restore-default =
+    .label = Adfer Peiriannau Chwilio Rhagosodedig
+    .accesskey = A
+search-remove-engine =
+    .label = Tynnu
+    .accesskey = T
+search-add-engine =
+    .label = Ychwanegu
+    .accesskey = Y
+search-find-more-link = Ychwanegu peiriannau chwilio eraill
+# This warning is displayed when the chosen keyword is already in use
+# ('Duplicate' is an adjective)
+search-keyword-warning-title = Allweddair Dyblyg
+# Variables:
+#   $name (String) - Name of a search engine.
+search-keyword-warning-engine = Rydych wedi defnyddio allweddair sy'n cael ei ddefnyddio gan "{ $name }". Dewiswch un arall.
+search-keyword-warning-bookmark = Rydych wedi defnyddio allweddair sy'n cael ei ddefnyddio gan nod tudalen. Dewiswch un arall.
+
+## Containers Section
+
+containers-back-button =
+    .aria-label =
+        { PLATFORM() ->
+            [windows] Nôl i Opsiynau
+           *[other] Nol i Dewisiadau
+        }
+containers-header = Tabiau Cynwysyddion
+containers-add-button =
+    .label = Ychwanegu Cynhwysydd Newydd
+    .accesskey = Y
+containers-new-tab-check =
+    .label = Dewiswch gynhwysydd ar gyfer pob tab newydd
+    .accesskey = g
+containers-preferences-button =
+    .label = Dewisiadau
+containers-remove-button =
+    .label = Tynnu
+
+## Firefox Account - Signed out. Note that "Sync" and "Firefox Account" are now
+## more discrete ("signed in" no longer means "and sync is connected").
+
+sync-signedout-caption = Mynd â'ch  Gwe gyda Chi
+sync-signedout-description = Cydweddwch eich nodau tudalen, hanes, tabiau, cyfrineiriau, ychwanegion a dewisiadau ymysg eich dyfeisiau i gyd.
+sync-signedout-account-signin2 =
+    .label = Mewngofnodi i { -sync-brand-short-name }…
+    .accesskey = M
+# This message contains two links and two icon images.
+#   `<img data-l10n-name="android-icon"/>` - Android logo icon
+#   `<a data-l10n-name="android-link">` - Link to Android Download
+#   `<img data-l10n-name="ios-icon">` - iOS logo icon
+#   `<a data-l10n-name="ios-link">` - Link to iOS Download
+#
+# They can be moved within the sentence as needed to adapt
+# to your language, but should not be changed or translated.
+sync-mobile-promo = Llwytho Firefox i lawr ar gyfer <img data-l10n-name="android-icon"/> <a data-l10n-name="android-link">Android</a> neu <img data-l10n-name="ios-icon"/> <a data-l10n-name="ios-link">iOS</a> i gydweddu gyda'ch dyfais symudol.
+
+## Firefox Account - Signed in
+
+sync-profile-picture =
+    .tooltiptext = Newid llun proffil
+sync-sign-out =
+    .label = Allgofnodi…
+    .accesskey = A
+sync-manage-account = Rheoli cyfrif
+    .accesskey = R
+sync-signedin-unverified = { $email } wedi ei wirio.
+sync-signedin-login-failure = Ail fewngofnodwch er mwyn ailgysylltu { $email }
+sync-resend-verification =
+    .label = Ail Anfon Dilysiad
+    .accesskey = A
+sync-remove-account =
+    .label = Tynnu Cyfrif
+    .accesskey = T
+sync-sign-in =
+    .label = Mewngofnodi
+    .accesskey = M
+
+## Sync section - enabling or disabling sync.
+
+prefs-syncing-on = Cydweddu: YMLAEN
+prefs-syncing-off = Cydweddu: DIFFODD
+prefs-sync-setup =
+    .label = Gosod { -sync-brand-short-name }
+    .accesskey = G
+prefs-sync-offer-setup-label = Cydweddwch eich nodau tudalen, hanes, tabiau, cyfrineiriau, ychwanegion a dewisiadau ar draws eich dyfeisiau i gyd.
+prefs-sync-now =
+    .labelnotsyncing = Cydweddu Nawr
+    .accesskeynotsyncing = N
+    .labelsyncing = Cydweddu…
+
+## The list of things currently syncing.
+
+sync-currently-syncing-heading = Rydych wrthi'n cydweddu'r eitemau hyn:
+sync-currently-syncing-bookmarks = Nodau Tudalen
+sync-currently-syncing-history = Hanes
+sync-currently-syncing-tabs = Tabiau agored
+sync-currently-syncing-logins-passwords = Mewngofnodion a chyfrineiriau
+sync-currently-syncing-addresses = Cyfeiriadau
+sync-currently-syncing-creditcards = Cardiau Credyd
+sync-currently-syncing-addons = Ychwanegion
+sync-currently-syncing-prefs =
+    { PLATFORM() ->
+        [windows] Opsiynau
+       *[other] Dewisiadau
+    }
+sync-change-options =
+    .label = Newid…
+    .accesskey = N
+
+## The "Choose what to sync" dialog.
+
+sync-choose-what-to-sync-dialog =
+    .title = Dewis Beth i'w Gydweddu
+    .style = width: 36em; min-height: 35em;
+    .buttonlabelaccept = Cadw Newidiadau
+    .buttonaccesskeyaccept = N
+    .buttonlabelextra2 = Datgysylltu…
+    .buttonaccesskeyextra2 = D
+sync-engine-bookmarks =
+    .label = Nodau Tudalen
+    .accesskey = T
+sync-engine-history =
+    .label = Hanes
+    .accesskey = H
+sync-engine-tabs =
+    .label = Agor tabiau
+    .tooltiptext = Rhestr o'r hyn sydd ar agor ar bob dyfais wedi eu cydweddu
+    .accesskey = T
+sync-engine-logins-passwords =
+    .label = Mewngofnodion a chyfrineiriau
+    .tooltiptext = Enwau defnyddwyr a chyfrineiriau rydych wedi'u cadw
+    .accesskey = M
+sync-engine-addresses =
+    .label = Cyfeiriadau
+    .tooltiptext = Cyfeiriadau post rydych wedi eu cadw (bwrdd gwaith yn unig)
+    .accesskey = y
+sync-engine-creditcards =
+    .label = Cardiau Credyd
+    .tooltiptext = Enwau, rhifau a dyddiadau dod i ben (bwrdd gwaith yn unig)
+    .accesskey = r
+sync-engine-addons =
+    .label = Ychwanegion
+    .tooltiptext = Estyniadau a themâu ar gyfer Firefox bwrdd gwaith
+    .accesskey = Y
+sync-engine-prefs =
+    .label =
+        { PLATFORM() ->
+            [windows] Opsiynau
+           *[other] Dewisiadau
+        }
+    .tooltiptext = Gosodiadau Cyffredinol, Preifatrwydd a Diogelwch rydych wedi eu newid
+    .accesskey = O
+
+## The device name controls.
+
+sync-device-name-header = Enw Dyfais
+sync-device-name-change =
+    .label = Newid Enw'r Ddyfais…
+    .accesskey = N
+sync-device-name-cancel =
+    .label = Diddymu
+    .accesskey = D
+sync-device-name-save =
+    .label = Cadw
+    .accesskey = C
+sync-connect-another-device = Cysylltu dyfais arall
+
+## Privacy Section
+
+privacy-header = Preifatrwydd y Porwr
+
+## Privacy Section - Logins and Passwords
+
+# The search keyword isn't shown to users but is used to find relevant settings in about:preferences.
+pane-privacy-logins-and-passwords-header = Mewngofnodion a Chyfrineiriau
+    .searchkeywords = { -lockwise-brand-short-name }
+# Checkbox to control whether UI is shown to users to save or fill logins/passwords.
+forms-ask-to-save-logins =
+    .label = Gofyn i gadw mewngofnodion a chyfrineiriau ar gyfer gwefannau
+    .accesskey = G
+forms-exceptions =
+    .label = Eithriadau…
+    .accesskey = i
+forms-generate-passwords =
+    .label = Awgrymu a chynhyrchu cyfrineiriau cryf
+    .accesskey = A
+forms-breach-alerts =
+    .label = Dangos rhybuddion am gyfrineiriau ar gyfer gwefannau sydd wedi' cael tor-data
+    .accesskey = r
+forms-breach-alerts-learn-more-link = Dysgu rhagor
+# Checkbox which controls filling saved logins into fields automatically when they appear, in some cases without user interaction.
+forms-fill-logins-and-passwords =
+    .label = Awtolanw mewngofnodion a chyfrineiriau
+    .accesskey = A
+forms-saved-logins =
+    .label = Mewngofnodion wedi eu Cadw…
+    .accesskey = M
+forms-master-pw-use =
+    .label = Defnyddio prif gyfrinair
+    .accesskey = D
+forms-primary-pw-use =
+    .label = Defnyddio Prif Gyfrinair
+    .accesskey = P
+forms-primary-pw-learn-more-link = Dysgu rhagor
+# This string uses the former name of the Primary Password feature
+# ("Master Password" in English) so that the preferences can be found
+# when searching for the old name. The accesskey is unused.
+forms-master-pw-change =
+    .label = Newid y Prif Gyfrinair…
+    .accesskey = N
+forms-master-pw-fips-title = Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+forms-primary-pw-change =
+    .label = Newid y Prif Gyfrinair…
+    .accesskey = N
+# Leave this message empty if the translation for "Primary Password" matches
+# "Master Password" in your language. If you're editing the FTL file directly,
+# use { "" } as the value.
+forms-primary-pw-former-name = { "" }
+forms-primary-pw-fips-title = Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+forms-master-pw-fips-desc = Methu Newid eich Cyfrinair
+
+## OS Authentication dialog
+
+# This message can be seen by trying to add a Master Password.
+master-password-os-auth-dialog-message-win = I greu Prif Gyfrinair, rhowch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen by trying to add a Master Password.
+# The macOS strings are preceded by the operating system with "Firefox is trying to "
+# and includes subtitle of "Enter password for the user "xxx" to allow this." These
+# notes are only valid for English. Please test in your locale.
+master-password-os-auth-dialog-message-macosx = creu Prif Gyfrinair
+# This message can be seen by trying to add a Primary Password.
+primary-password-os-auth-dialog-message-win = I greu Prif Gyfrinair, nodwch fanylion eich mewngofnodi Windows. Mae hyn yn helpu i ddiogelu eich cyfrifon.
+# This message can be seen by trying to add a Primary Password.
+# The macOS strings are preceded by the operating system with "Firefox is trying to "
+# and includes subtitle of "Enter password for the user "xxx" to allow this." These
+# notes are only valid for English. Please test in your locale.
+primary-password-os-auth-dialog-message-macosx = creu Prif Gyfrinair
+master-password-os-auth-dialog-caption = { -brand-full-name }
+
+## Privacy Section - History
+
+history-header = Hanes
+# This label is followed, on the same line, by a dropdown list of options
+# (Remember history, etc.).
+# In English it visually creates a full sentence, e.g.
+# "Firefox will" + "Remember history".
+#
+# If this doesn't work for your language, you can translate this message:
+#   - Simply as "Firefox", moving the verb into each option.
+#     This will result in "Firefox" + "Will remember history", etc.
+#   - As a stand-alone message, for example "Firefox history settings:".
+history-remember-label = Bydd { -brand-short-name } yn
+    .accesskey = B
+history-remember-option-all =
+    .label = Cofio hanes
+history-remember-option-never =
+    .label = Peidio cofio hanes
+history-remember-option-custom =
+    .label = Defnyddio gosodiadau cyfaddas ar gyfer hanes
+history-remember-description = Bydd { -brand-short-name } yn cofio eich hanes pori, llwytho i lawr, ffurflenni a chwilio.
+history-dontremember-description = Bydd { -brand-short-name } yn defnyddio'r un gosodiadau â phori preifat, ond ni fydd yn cofio unrhyw hanes wrth i chi bori'r We.
+history-private-browsing-permanent =
+    .label = Defnyddio'r modd pori preifat bob tro
+    .accesskey = p
+history-remember-browser-option =
+    .label = Cofio hanes pori a llwytho i lawr
+    .accesskey = h
+history-remember-search-option =
+    .label = Cofio hanes chwilio a ffurflen
+    .accesskey = C
+history-clear-on-close-option =
+    .label = Clirio hanes pan fydd { -brand-short-name } yn cau
+    .accesskey = l
+history-clear-on-close-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+history-clear-button =
+    .label = Clirio Hanes…
+    .accesskey = H
+
+## Privacy Section - Site Data
+
+sitedata-header = Cwcis a Data Gwefan
+sitedata-total-size-calculating = Cyfrifo maint data gwefan a storfa dros dro…
+# Variables:
+#   $value (Number) - Value of the unit (for example: 4.6, 500)
+#   $unit (String) - Name of the unit (for example: "bytes", "KB")
+sitedata-total-size = Mae'r cwcis, data gwefan a storfa dros dro yn defnyddio { $value } { $unit } o le ar ddisg ar hyn o bryd.
+sitedata-learn-more = Dysgu rhagor
+sitedata-delete-on-close =
+    .label = Dileu cwcis a data'r wefan pan fydd { -brand-short-name } yn cau
+    .accesskey = D
+sitedata-delete-on-close-private-browsing = Yn y modd pori preifat parhaol, bydd cwcis a data'r wefan yn cael eu clirio bob tro pan fydd { -brand-short-name } yn cau.
+sitedata-allow-cookies-option =
+    .label = Derbyn cwcis a data gan wefannau
+    .accesskey = D
+sitedata-disallow-cookies-option =
+    .label = Rhwystro cwcis a data gwefan
+    .accesskey = R
+# This label means 'type of content that is blocked', and is followed by a drop-down list with content types below.
+# The list items are the strings named sitedata-block-*-option*.
+sitedata-block-desc = Mathau wedi'u rhwystro
+    .accesskey = M
+sitedata-option-block-cross-site-trackers =
+    .label = Tracwyr traws-gwefan
+sitedata-option-block-cross-site-and-social-media-trackers =
+    .label = Tracwyr traws-gwefan a chyfryngau cymdeithasol
+sitedata-option-block-cross-site-tracking-cookies-including-social-media =
+    .label = Cwcis tracio traws-gwefan - yn cynnwys cwcis cyfryngau cymdeithasol
+sitedata-option-block-cross-site-cookies-including-social-media =
+    .label = Cwcis traws-gwefan - yn cynnwys cwcis cyfryngau cymdeithasol
+sitedata-option-block-cross-site-and-social-media-trackers-plus-isolate =
+    .label = Tracwyr traws-safle a chyfryngau cymdeithasol, ac ynysu'r cwcis sy'n weddill
+sitedata-option-block-unvisited =
+    .label = Cwcis o wefannau heb ymweld â nhw
+sitedata-option-block-all-third-party =
+    .label = Pob cwci trydydd parti (gall achosi i wefannau i dorri)
+sitedata-option-block-all =
+    .label = Pob cwci (bydd yn achosi i wefannau dorri)
+sitedata-clear =
+    .label = Clirio Data…
+    .accesskey = l
+sitedata-settings =
+    .label = Rheoli Data…
+    .accesskey = R
+sitedata-cookies-permissions =
+    .label = Rheoli Caniatâd...
+    .accesskey = R
+sitedata-cookies-exceptions =
+    .label = Rheoli Eithriadau…
+    .accesskey = R
+
+## Privacy Section - Address Bar
+
+addressbar-header = Bar Cyfeiriadau
+addressbar-suggest = Pan yn defnyddio'r bar cyfeiriad, cynnig
+addressbar-locbar-history-option =
+    .label = Hanes pori
+    .accesskey = p
+addressbar-locbar-bookmarks-option =
+    .label = Nodau Tudalen
+    .accesskey = N
+addressbar-locbar-openpage-option =
+    .label = Tabiau agored
+    .accesskey = T
+# Shortcuts refers to the shortcut tiles on the new tab page, previously known as top sites. Translation should be consistent.
+addressbar-locbar-shortcuts-option =
+    .label = Llwybrau Byr
+    .accesskey = L
+addressbar-locbar-topsites-option =
+    .label = Hoff wefannau
+    .accesskey = H
+addressbar-locbar-engines-option =
+    .label = Peiriannau chwilio
+    .accesskey = P
+addressbar-suggestions-settings = Newid dewisiadau am awgrymiadau peiriannau chwilio
+
+## Privacy Section - Content Blocking
+
+content-blocking-enhanced-tracking-protection = Diogelwch Uwch Rhag Tracio
+content-blocking-section-top-level-description = Mae tracwyr yn eich dilyn ar-lein i gasglu gwybodaeth am eich arferion pori a'ch diddordebau. Mae { -brand-short-name } yn rhwystro llawer o'r tracwyr hyn a sgriptiau maleisus eraill.
+content-blocking-learn-more = Dysgu Rhagor
+content-blocking-fpi-incompatibility-warning = Rydych yn defnyddio Ynysu Parti Cyntaf (FPI), sy’n gwrthwneud rhai o osodiadau cwci { -brand-short-name } ’.
+
+## These strings are used to define the different levels of
+## Enhanced Tracking Protection.
+
+# "Standard" in this case is an adjective, meaning "default" or "normal".
+enhanced-tracking-protection-setting-standard =
+    .label = Safonol
+    .accesskey = S
+enhanced-tracking-protection-setting-strict =
+    .label = Llym
+    .accesskey = L
+enhanced-tracking-protection-setting-custom =
+    .label = Cyfaddasu
+    .accesskey = C
+
+##
+
+content-blocking-etp-standard-desc = Cydbwysedd rhwng diogelwch a pherfformiad. Bydd tudalennau'n llwytho fel arfer.
+content-blocking-etp-strict-desc = Diogelwch cryfach, ond gall achosi i rai gwefannau neu gynnwys dorri.
+content-blocking-etp-custom-desc = Dewiswch pa dracwyr a sgriptiau i'w rhwystro.
+content-blocking-private-windows = Tracio cynnwys mewn Ffenestri Preifat
+content-blocking-cross-site-cookies = Cwcis traws-gwefan
+content-blocking-cross-site-tracking-cookies = Cwcis tracio traws-gwefan
+content-blocking-cross-site-tracking-cookies-plus-isolate = Cwcis tracio traws-safle, ac ynysu'r cwcis sy'n weddill
+content-blocking-social-media-trackers = Tracwyr cyfryngau cymdeithasol
+content-blocking-all-cookies = Pob cwci
+content-blocking-unvisited-cookies = Cwcis o safleoedd heb ymweld â nhw
+content-blocking-all-windows-tracking-content = Tracio cynnwys ym mhob ffenestr
+content-blocking-all-third-party-cookies = Pob cwci trydydd parti
+content-blocking-cryptominers = Cryptogloddwyr
+content-blocking-fingerprinters = Bysbrintwyr
+content-blocking-warning-title = Rhybudd!
+content-blocking-and-isolating-etp-warning-description = Gall rhwystro tracwyr effeithio ar ymarferoldeb rhai gwefannau. Ail-lwythwch dudalen gyda thracwyr i lwytho'r holl gynnwys.
+content-blocking-and-isolating-etp-warning-description-2 = Gall y gosodiad hwn beri i rai gwefannau beidio a dangos cynnwys na gweithio'n iawn. Os yw gwefan yn ymddangos wedi torri, efallai yr hoffech chi ddiffodd diogelu rhag tracio i'r wefan honno lwytho'r holl gynnwys.
+content-blocking-warning-learn-how = Dysgu sut
+content-blocking-reload-description = Bydd angen ail lwytho'ch tabiau i osod y newidiadau hyn.
+content-blocking-reload-tabs-button =
+    .label = Ail lwytho Pob Tab
+    .accesskey = A
+content-blocking-tracking-content-label =
+    .label = Cynnwys tracio
+    .accesskey = t
+content-blocking-tracking-protection-option-all-windows =
+    .label = Ym mhob ffenestr
+    .accesskey = f
+content-blocking-option-private =
+    .label = Dim ond mewn Ffenestri Preifat
+    .accesskey = P
+content-blocking-tracking-protection-change-block-list = Newid y rhestr rhwystro
+content-blocking-cookies-label =
+    .label = Cwcis
+    .accesskey = C
+content-blocking-expand-section =
+    .tooltiptext = Rhagor o wybodaeth
+# Cryptomining refers to using scripts on websites that can use a computer’s resources to mine cryptocurrency without a user’s knowledge.
+content-blocking-cryptominers-label =
+    .label = Cryptogloddwyr
+    .accesskey = y
+# Browser fingerprinting is a method of tracking users by the configuration and settings information (their "digital fingerprint")
+# that is visible to websites they browse, rather than traditional tracking methods such as IP addresses and unique cookies.
+content-blocking-fingerprinters-label =
+    .label = Bysbrintwyr
+    .accesskey = B
+
+## Privacy Section - Tracking
+
+tracking-manage-exceptions =
+    .label = Rheoli Eithriadau…
+    .accesskey = R
+
+## Privacy Section - Permissions
+
+permissions-header = Caniatâd
+permissions-location = Lleoliad
+permissions-location-settings =
+    .label = Gosodiadau…
+    .accesskey = d
+permissions-xr = Rhithrealaeth
+permissions-xr-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+permissions-camera = Camera
+permissions-camera-settings =
+    .label = Gosodiadau…
+    .accesskey = s
+permissions-microphone = Meicroffon
+permissions-microphone-settings =
+    .label = Gosodiadau…
+    .accesskey = o
+permissions-notification = Hysbysiadau
+permissions-notification-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+permissions-notification-link = Dysgu rhagor
+permissions-notification-pause =
+    .label = Oedi fy hysbysiadau tan { -brand-short-name } ailgychwyn
+    .accesskey = O
+permissions-autoplay = Awtochwarae
+permissions-autoplay-settings =
+    .label = Gosodiadau…
+    .accesskey = G
+permissions-block-popups =
+    .label = Rhwystro ffenestri llamlen
+    .accesskey = R
+permissions-block-popups-exceptions =
+    .label = Eithriadau…
+    .accesskey = E
+permissions-addon-install-warning =
+    .label = Rhybuddio pan fydd gwefan yn ceisio gosod ychwanegion
+    .accesskey = y
+permissions-addon-exceptions =
+    .label = Eithriadau…
+    .accesskey = E
+permissions-a11y-privacy-checkbox =
+    .label = Atal gwasanaethau hygyrchedd rhag cael mynediad i'ch porwr
+    .accesskey = a
+permissions-a11y-privacy-link = Dysgu rhagor
+
+## Privacy Section - Data Collection
+
+collection-header = Casglu Data a'r Defnydd o { -brand-short-name }
+collection-description = Rydym yn ceisio darparu dewisiadau i chi a chasglu dim ond beth sydd ei angen arnom i ddarparu a gwella { -brand-short-name } ar gyfer pawb. Rydym yn gofyn caniatâd bob tro cyn derbyn manylion personol.
+collection-privacy-notice = Rhybudd Preifatrwydd
+collection-health-report-telemetry-disabled = Nid ydych bellach yn caniatáu i { -vendor-short-name } ddal data technegol a rhyngweithiol. Bydd holl ddata'r gorffennol yn cael ei ddileu cyn pen 30 diwrnod.
+collection-health-report-telemetry-disabled-link = Dysgu rhagor
+collection-health-report =
+    .label = Caniatáu i { -brand-short-name } anfon data technegol a rhyngweithio i { -vendor-short-name }
+    .accesskey = r
+collection-health-report-link = Dysgu rhagor
+collection-studies =
+    .label = Caniatáu i { -brand-short-name } osod a rhedeg astudiaethau
+collection-studies-link = Gweld astudiaethau { -brand-short-name }
+addon-recommendations =
+    .label = Caniatáu i { -brand-short-name } wneud argymhellion personol am estyniadau
+addon-recommendations-link = Dysgu rhagor
+# This message is displayed above disabled data sharing options in developer builds
+# or builds with no Telemetry support available.
+collection-health-report-disabled = Mae adrodd ar ddata wedi ei analluogi ar gyfer ffurfweddiad yr adeiledd hwn
+collection-backlogged-crash-reports =
+    .label = Caniatáu i { -brand-short-name } i anfon adroddiadau chwalu wedi eu cadw ar eich rhan
+    .accesskey = c
+collection-backlogged-crash-reports-link = Dysgu rhagor
+
+## Privacy Section - Security
+##
+## It is important that wording follows the guidelines outlined on this page:
+## https://developers.google.com/safe-browsing/developers_guide_v2#AcceptableUsage
+
+security-header = Diogelwch
+security-browsing-protection = Diogelwch rhag Cynnwys Twyllodrus a Meddalwedd Peryglus
+security-enable-safe-browsing =
+    .label = Rhwystro cynnwys peryglus a thwyllodrus
+    .accesskey = R
+security-enable-safe-browsing-link = Dysgu rhagor
+security-block-downloads =
+    .label = Rhwystro llwytho i lawr peryglus
+    .accesskey = p
+security-block-uncommon-software =
+    .label = Rhybuddio fi am feddalwedd digroeso ac anghyffredin
+    .accesskey = a
+
+## Privacy Section - Certificates
+
+certs-header = Tystysgrifau
+certs-personal-label = Pan fydd gweinydd yn gofyn am fy nhystysgrif bersonol:
+certs-select-auto-option =
+    .label = Dewis un yn awtomatig
+    .accesskey = T
+certs-select-ask-option =
+    .label = Gofyn i mi bob tro
+    .accesskey = G
+certs-enable-ocsp =
+    .label = Gofyn i weinyddion atebwr OCSP i gadarnhau dilysrwydd cyfredol y tystysgrifau
+    .accesskey = G
+certs-view =
+    .label = Darllen Tystysgrifau…
+    .accesskey = D
+certs-devices =
+    .label = Dyfeisiau Diogelwch…
+    .accesskey = y
+space-alert-learn-more-button =
+    .label = Dysgu Rhagor
+    .accesskey = D
+space-alert-over-5gb-pref-button =
+    .label =
+        { PLATFORM() ->
+            [windows] Agor Opsiynau
+           *[other] Agor Dewisiadau
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [windows] O
+           *[other] D
+        }
+space-alert-over-5gb-message =
+    { PLATFORM() ->
+        [windows] Mae { -brand-short-name } yn brin o le ar ddisg. Efallai na fydd cynnwys gwefan yn cael ei ddangos yn iawn. Mae modd i chi glirio data wedi ei storio yn Opsiynau> Preifatrwydd a Diogelwch > Cwcis a Data Gwefan.
+       *[other] Mae { -brand-short-name } yn brin o le ar ddisg. Efallai na fydd cynnwys gwefan yn cael ei ddangos yn iawn. Mae modd i chi glirio data wedi ei storio yn Dewisiadau > Preifatrwydd a Diogelwch > Cwcis a Data Gwefan.
+    }
+space-alert-under-5gb-ok-button =
+    .label = Iawn
+    .accesskey = I
+space-alert-under-5gb-message = Mae { -brand-short-name } yn brin o le ar ddisg. Efallai na fydd cynnwys gwefan yn cael ei ddangos yn iawn. Ewch i “Learn More” i wella'r defnydd o'r disg ar gyfer gwell profiad pori.
+
+## Privacy Section - HTTPS-Only
+
+httpsonly-header = Modd HTTPS-yn-Unig
+httpsonly-description = Mae HTTPS yn darparu cysylltiad diogel, wedi'i amgryptio rhwng  { -brand-short-name } a'r gwefannau rydych chi'n ymweld â nhw. Mae'r mwyafrif o wefannau yn cefnogi HTTPS, ac os yw Modd HTTPS-yn-Unig wedi'i alluogi, yna bydd { -brand-short-name } yn uwchraddio'r holl gysylltiadau â HTTPS.
+httpsonly-learn-more = Dysgu rhagor
+httpsonly-radio-enabled =
+    .label = Galluogi Modd HTTPS-yn-Unig ym mhob ffenestr
+httpsonly-radio-enabled-pbm =
+    .label = Galluogi Modd HTTPS-yn-Unig mewn ffenestri preifat yn unig
+httpsonly-radio-disabled =
+    .label = Peidio â galluogi Modd HTTPS-yn-Unig
+
+## The following strings are used in the Download section of settings
+
+desktop-folder-name = Bwrdd Gwaith
+downloads-folder-name = Llwythi
+choose-download-folder-title = Dewis Ffolder Llwytho i Lawr:
+# Variables:
+#   $service-name (String) - Name of a cloud storage provider like Dropbox, Google Drive, etc...
+save-files-to-cloud-storage =
+    .label = Cadw ffeiliau i { $service-name }
diff --git a/l10n-cy/browser/browser/preferences/selectBookmark.ftl b/l10n-cy/browser/browser/preferences/selectBookmark.ftl
new file mode 100644
index 0000000000..ec50f815eb
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/selectBookmark.ftl
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+select-bookmark-window =
+    .title = Gosod Tudalen Cartref
+    .style = width: 32em;
+
+select-bookmark-desc = Dewiswch Nod Tudalen i fod yn Dudalen Cartref. Os fyddwch yn dewis ffolder, bydd y Nodau Tudalen yn y ffolder yn cael eu hagor mewn Tabiau.
diff --git a/l10n-cy/browser/browser/preferences/siteDataSettings.ftl b/l10n-cy/browser/browser/preferences/siteDataSettings.ftl
new file mode 100644
index 0000000000..4ce21cc731
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/siteDataSettings.ftl
@@ -0,0 +1,57 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Settings
+
+site-data-settings-window =
+    .title = Rheoli Cwcis a Data Gwefan
+site-data-settings-description = Mae'r gwefannau canlynol yn cadw cwcis a data gwefan ar eich cyfrifiadur. Mae { -brand-short-name } yn cadw data o wefannau sydd â storio parhaus nes i chi eu dileu, ac yn dileu data o wefannau sydd heb storfa parhaus yn ôl yr angen am le ar ddisg.
+site-data-search-textbox =
+    .placeholder = Chwilio gwefannau
+    .accesskey = C
+site-data-column-host =
+    .label = Gwefan
+site-data-column-cookies =
+    .label = Cwcis
+site-data-column-storage =
+    .label = Storfa
+site-data-column-last-used =
+    .label = Defnyddiwyd Diwethaf
+# This label is used in the "Host" column for local files, which have no host.
+site-data-local-file-host = (ffeil leol)
+site-data-remove-selected =
+    .label = Tynnu'r Dewis
+    .accesskey = T
+site-data-button-cancel =
+    .label = Diddymu
+    .accesskey = D
+site-data-button-save =
+    .label = Cadw Newidiadau
+    .accesskey = a
+site-data-settings-dialog =
+    .buttonlabelaccept = Cadw Newidiadau
+    .buttonaccesskeyaccept = a
+# Variables:
+#   $value (Number) - Value of the unit (for example: 4.6, 500)
+#   $unit (String) - Name of the unit (for example: "bytes", "KB")
+site-storage-usage =
+    .value = { $value } { $unit }
+site-storage-persistent =
+    .value = { site-storage-usage.value } (Parhaus)
+site-data-remove-all =
+    .label = Tynnu Popeth
+    .accesskey = P
+site-data-remove-shown =
+    .label = Tynnu Popeth Dangoswyd
+    .accesskey = y
+
+## Removing
+
+site-data-removing-dialog =
+    .title = { site-data-removing-header }
+    .buttonlabelaccept = Tynnu
+site-data-removing-header = Tynnu Cwcis a Data Gwefan
+site-data-removing-desc = Gall dynnu cwcis a data gwefan eich allgofnodi o wefannau. Ydych chi'n siŵr eich bod am wneud y newidiadau hyn?
+site-data-removing-table = Bydd cwcis a data gwefan yn cael eu tynnu o'r gwefannau canlynol
diff --git a/l10n-cy/browser/browser/preferences/translation.ftl b/l10n-cy/browser/browser/preferences/translation.ftl
new file mode 100644
index 0000000000..8ee48581b1
--- /dev/null
+++ b/l10n-cy/browser/browser/preferences/translation.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+translation-window =
+    .title = Eithriadau - Cyfieithiad
+    .style = width: 36em
+translation-close-key =
+    .key = w
+translation-languages-disabled-desc = Ni fydd cyfieithiad yn cael ei gynnig ar gyfer yr ieithoedd canlynol
+translation-languages-column =
+    .label = Iaith
+translation-languages-button-remove =
+    .label = Tynnu Iaith
+    .accesskey = T
+translation-languages-button-remove-all =
+    .label = Tynnu Pob Iaith
+    .accesskey = y
+translation-sites-disabled-desc = Ni fydd cyfieithiad yn cael ei gynnig o'r gwefannau canlynol
+translation-sites-column =
+    .label = Gwefannau
+translation-sites-button-remove =
+    .label = Tynnu'r Wefan
+    .accesskey = W
+translation-sites-button-remove-all =
+    .label = Tynnu Pob Gwefan
+    .accesskey = G
+translation-button-close =
+    .label = Cau
+    .accesskey = C
+translation-dialog =
+    .buttonlabelaccept = Cau
+    .buttonaccesskeyaccept = C
diff --git a/l10n-cy/browser/browser/protections.ftl b/l10n-cy/browser/browser/protections.ftl
new file mode 100644
index 0000000000..cf625698ad
--- /dev/null
+++ b/l10n-cy/browser/browser/protections.ftl
@@ -0,0 +1,270 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Variables:
+#   $count (Number) - Number of tracking events blocked.
+graph-week-summary =
+    { $count ->
+        [zero] Mae { -brand-short-name } wedi rhwystro { $count } tracwyr yn ystod yr wythnos ddiwethaf
+        [one] Mae { -brand-short-name } wedi rhwystro { $count } traciwr yn ystod yr wythnos ddiwethaf
+        [two] Mae { -brand-short-name } wedi rhwystro { $count } draciwr yn ystod yr wythnos ddiwethaf
+        [few] Mae { -brand-short-name } wedi rhwystro { $count } traciwr yn ystod yr wythnos ddiwethaf
+        [many] Mae { -brand-short-name } wedi rhwystro { $count } traciwr yn ystod yr wythnos ddiwethaf
+       *[other] Mae { -brand-short-name } wedi rhwystro { $count } traciwr yn ystod yr wythnos ddiwethaf
+    }
+# Variables:
+#   $count (Number) - Number of tracking events blocked.
+#   $earliestDate (Number) - Unix timestamp in ms, representing a date. The
+# earliest date recorded in the database.
+graph-total-tracker-summary =
+    { $count ->
+        [zero] <b>{ $count }</b> tracwyr wedi eu rhwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+        [one] <b>{ $count }</b> traciwr wedi ei rwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+        [two] <b>{ $count }</b> draciwr wedi eu rwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+        [few] <b>{ $count }</b> traciwr wedi eu rwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+        [many] <b>{ $count }</b> thraciwr wedi eu rwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+       *[other] <b>{ $count }</b> traciwr wedi eu rwystro ers{ DATETIME($earliestDate, day: "numeric", month: "long", year: "numeric") }
+    }
+# Text displayed instead of the graph when in Private Mode
+graph-private-window = Mae { -brand-short-name } yn parhau i rwystro tracwyr mewn Ffenestri Preifat, ond nid yw'n cadw cofnod o'r hyn gafodd ei rwystro.
+# Weekly summary of the graph when the graph is empty in Private Mode
+graph-week-summary-private-window = Tracwyr rhwystrodd { -brand-short-name } yr wythnos hon
+protection-report-webpage-title = Bwrdd Gwaith Diogelwch
+protection-report-page-content-title = Bwrdd Gwaith Diogelwch
+# This message shows when all privacy protections are turned off, which is why we use the word "can", Firefox is able to protect your privacy, but it is currently not.
+protection-report-page-summary = Gall { -brand-short-name } ddiogelu eich preifatrwydd y tu ôl i'r llenni wrth i chi bori. Mae hwn yn grynodeb wedi'i bersonoli o'r diogelwch hynny, gan gynnwys offer i reoli eich diogelwch ar-lein.
+# This message shows when at least some protections are turned on, we are more assertive compared to the message above, Firefox is actively protecting you.
+protection-report-page-summary-default = Mae { -brand-short-name } yn diogelu eich preifatrwydd y tu ôl i'r llenni wrth i chi bori. Mae hwn yn grynodeb wedi'i bersonoli o'r diogelwch hynny, gan gynnwys offer i reoli'ch diogelwch ar-lein.
+protection-report-settings-link = Rheoli eich gosodiadau preifatrwydd a diogelwch
+etp-card-title-always = Diogelwch Uwch Rhag Tracio: Ymlaen Drwy'r Amser
+etp-card-title-custom-not-blocking = Diogelwch Uwch Rhag Tracio: I FFWRDD
+etp-card-content-description = Mae { -brand-short-name } yn atal cwmnïau rhag eich dilyn yn gyfrinachol o amgylch y we, yn awtomatig.
+protection-report-etp-card-content-custom-not-blocking = Mae'r holl ddiogelu wedi'u diffodd ar hyn o bryd. Dewiswch pa dracwyr i'w rhwystro trwy reoli eich gosodiadau diogelu { -brand-short-name }.
+protection-report-manage-protections = Rheoli Gosodiadau
+# This string is used to label the X axis of a graph. Other days of the week are generated via Intl.DateTimeFormat,
+# capitalization for this string should match the output for your locale.
+graph-today = Heddiw
+# This string is used to describe the graph for screenreader users.
+graph-legend-description = Graff sy'n cynnwys cyfanswm nifer pob math o draciwr gafodd ei rwystro yr wythnos hon.
+social-tab-title = Tracwyr Cyfryngau Cymdeithasol
+social-tab-contant = Mae rhwydweithiau cymdeithasol yn gosod tracwyr ar wefannau eraill i ddilyn yr hyn rydych chi'n ei wneud, ei weld, a'i wylio ar-lein. Mae hyn yn caniatáu i gwmnïau cyfryngau cymdeithasol ddysgu rhagor amdanoch chi y tu hwnt i'r hyn rydych chi'n ei rannu ar eich proffiliau cyfryngau cymdeithasol. <a data-l10n-name="learn-more-link">Dysgu rhagor</a>
+cookie-tab-title = Cwcis Tracio Traws-Gwefan
+cookie-tab-content = Mae'r cwcis hyn yn eich dilyn o wefan i wefan i gasglu data am yr hyn rydych chi'n ei wneud ar-lein. Mae nhw'n cael eu gosod gan drydydd partïon fel hysbysebwyr a chwmnïau dadansoddeg. Mae rhwystro cwcis tracio traws-safle yn lleihau'r nifer o hysbysebion sy'n eich dilyn. <a data-l10n-name="learn-more-link">Dysgu rhagor</a>
+tracker-tab-title = Tracio Cynnwys
+tracker-tab-description = Gall gwefannau lwytho hysbysebion allanol, fideos a chynnwys eraill sy'n cynnwys cod tracio. Gall rhwystro cynnwys tracio helpu gwefannau i lwytho'n gynt, ond efallai na fydd rhai botymau, ffurflenni a meysydd mewngofnodi'n gweithio. <a data-l10n-name="learn-more-link">Dysgu rhagor</a>
+fingerprinter-tab-title = Bysbrintwyr
+fingerprinter-tab-content = Mae bysbrintwyr yn casglu gosodiadau o'ch porwr a'ch cyfrifiadur i greu proffil ohonoch. Gan ddefnyddio'r olion bys digidol hwn, mae nhw'n gallu'ch tracio ar draws gwahanol wefannau. <a data-l10n-name="learn-more-link">Dysgu rhagor</a>
+cryptominer-tab-title = Cryptogloddwyr
+cryptominer-tab-content = Mae cryptogloddwyr yn defnyddio pŵer cyfrifiadurol eich system i gloddio arian digidol. Mae sgriptiau cryptogloddio yn gwagio eich batri, arafu eich cyfrifiadur, a gall gynyddu eich bil trydan. <a data-l10n-name="learn-more-link">Dysgu rhagor</a>
+protections-close-button2 =
+    .aria-label = Cau
+    .title = Cau
+mobile-app-title = Rhwystrwch dracwyr hysbysebion ar draws rhagor o ddyfeisiau
+mobile-app-card-content = Defnyddiwch y porwr symudol gydag diogelwch mewnol rhag tracio gan hysbysebion.
+mobile-app-links = Porwr { -brand-product-name } ar gyfer <a data-l10n-name="android-mobile-inline-link">Android</a> a <a data-l10n-name="ios-mobile-inline-link">iOS</a>
+lockwise-title = Peidiwch byth ag anghofio cyfrinair eto
+lockwise-title-logged-in2 = Rheoli Cyfrineiriau
+lockwise-header-content = Mae { -lockwise-brand-name } yn cadw'ch cyfrineiriau yn ddiogel yn eich porwr.
+lockwise-header-content-logged-in = Cadwch a chydweddwch eich cyfrineiriau'n ddiogel i'ch holl ddyfeisiau.
+protection-report-save-passwords-button = Cadw Cyfrineiriau
+    .title = Cadw Cyfrineiriau ar { -lockwise-brand-short-name }
+protection-report-manage-passwords-button = Rheoli Cyfrineiriau
+    .title = Rheoli Cyfrineiriau ar { -lockwise-brand-short-name }
+lockwise-mobile-app-title = Ewch â'ch cyfrineiriau i bob man
+lockwise-no-logins-card-content = Defnyddiwch gyfrineiriau wedi'u cadw yn { -brand-short-name } ar unrhyw ddyfais.
+lockwise-app-links = { -lockwise-brand-name } ar gyfer <a data-l10n-name="lockwise-android-inline-link">Android</a> a <a data-l10n-name = "lockwise-ios-inline-link" >iOS</a>
+# Variables:
+# $count (Number) - Number of passwords exposed in data breaches.
+lockwise-scanned-text-breached-logins =
+    { $count ->
+        [zero] Efallai bod { $count } cyfrineiriau wedi cael eu hamlygu mewn tor-data.
+        [one] Efallai bod i 1 cyfrinair wedi cael ei amlygu mewn tor-data.
+        [two] Efallai bod { $count } gyfrinair wedi cael eu hamlygu mewn tor-data.
+        [few] Efallai bod { $count } cyfrinair wedi cael eu hamlygu mewn tor-data.
+        [many] Efallai bod { $count } chyfrinair wedi cael eu hamlygu mewn tor-data.
+       *[other] Efallai bod { $count } cyfrinair wedi cael eu hamlygu mewn tor-data.
+    }
+# While English doesn't use the number in the plural form, you can add $count to your language
+# if needed for grammatical reasons.
+# Variables:
+# $count (Number) - Number of passwords stored in Lockwise.
+lockwise-scanned-text-no-breached-logins =
+    { $count ->
+        [zero] Mae'ch cyfrineiriau'n cael eu cadw'n ddiogel.
+        [one] Mae 1 cyfrinair yn cael ei gadw'n ddiogel.
+        [two] Mae'ch cyfrineiriau'n cael eu cadw'n ddiogel.
+        [few] Mae'ch cyfrineiriau'n cael eu cadw'n ddiogel.
+        [many] Mae'ch cyfrineiriau'n cael eu cadw'n ddiogel.
+       *[other] Mae'ch cyfrineiriau'n cael eu cadw'n ddiogel.
+    }
+lockwise-how-it-works-link = Sut mae'n gweithio
+turn-on-sync = Cychwyn { -sync-brand-short-name }…
+    .title = Mynd i ddewisiadau cydweddu
+monitor-title = Bod yn effro i dor-data.
+monitor-link = Sut mae'n gweithio
+monitor-header-content-no-account = Edrychwch ar { -monitor-brand-name } i weld a ydych chi wedi bod yn rhan o dor-data a chael rhybuddion am dor-data newydd.
+monitor-header-content-signed-in = Mae { -monitor-brand-name } yn eich rhybuddio os yw'ch manylion wedi ymddangos mewn tor-data hysbys
+monitor-sign-up-link = Cofrestrwch am Rybuddion Tor-data
+    .title = Cofrestrwch am rybuddion tor-data ar { -monitor-brand-name }
+auto-scan = Wedi'u sganio'n awtomatig heddiw
+monitor-emails-tooltip =
+    .title = Gweld cyfeiriadau e-bost wedi'u monitro ar { -monitor-brand-short-name }
+monitor-breaches-tooltip =
+    .title = Gweld tor-data hysbys ar { -monitor-brand-short-name }
+monitor-passwords-tooltip =
+    .title = Gweld cyfrineiriau wedi'u datgelu ar { -monitor-brand-short-name }
+# This string is displayed after a large numeral that indicates the total number
+# of email addresses being monitored. Don’t add $count to
+# your localization, because it would result in the number showing twice.
+info-monitored-emails =
+    { $count ->
+        [zero] Cyfeiriadau e-bost yn cael eu monitro
+        [one] Cyfeiriad e-bost yn cael ei fonitro
+        [two] Gyfeiriad e-bost yn cael eu monitro
+        [few] Cyfeiriad e-bost yn cael eu monitro
+        [many] Chyfeiriad e-bost yn cael eu monitro
+       *[other] Cyfeiriad e-bost yn cael eu monitro
+    }
+# This string is displayed after a large numeral that indicates the total number
+# of known data breaches. Don’t add $count to
+# your localization, because it would result in the number showing twice.
+info-known-breaches-found =
+    { $count ->
+        [zero] Tor-data hysbys wedi amlygu eich manylion
+        [one] Tor-data hysbys wedi amlygu eich manylion
+        [two] Dor-data hysbys wedi amlygu eich manylion
+        [few] Tor-data hysbys wedi amlygu eich manylion
+        [many] Thor-data hysbys wedi amlygu eich manylion
+       *[other] Tor-data hysbys wedi amlygu eich manylion
+    }
+# This string is displayed after a large numeral that indicates the total number
+# of known data breaches that are marked as resolved by the user. Don’t add $count
+# to your localization, because it would result in the number showing twice.
+info-known-breaches-resolved =
+    { $count ->
+        [zero] Tor-data hysbys wedi'u nodi fel wedi'u datrys
+        [one] Tor-data hysbys wedi'i nodi fel wedi'i ddatrys
+        [two] Dor-data hysbys wedi'u nodi fel wedi'u datrys
+        [few] Tor-data hysbys wedi'u nodi fel wedi'u datrys
+        [many] Thor-data hysbys wedi'u nodi fel wedi'u datrys
+       *[other] Tor-data hysbys wedi'u nodi fel wedi'u datrys
+    }
+# This string is displayed after a large numeral that indicates the total number
+# of exposed passwords. Don’t add $count to
+# your localization, because it would result in the number showing twice.
+info-exposed-passwords-found =
+    { $count ->
+        [zero] Cyfrineiriau wedi'u hamlygu ym mhob tor-data
+        [one] Cyfrinair wedi'i amlygu ym mhob tor-data
+        [two] Cyfrinair wedi'u hamlygu ym mhob tor-data
+        [few] Cyfrinair wedi'u hamlygu ym mhob tor-data
+        [many] Chyfrinair wedi'u hamlygu ym mhob tor-data
+       *[other] Cyfrinair wedi'u hamlygu ym mhob tor-data
+    }
+# This string is displayed after a large numeral that indicates the total number
+# of exposed passwords that are marked as resolved by the user. Don’t add $count
+# to your localization, because it would result in the number showing twice.
+info-exposed-passwords-resolved =
+    { $count ->
+        [zero] Cyfrineiriau wedi'u hamlygu mewn tor-data heb eu datrys
+        [one] Cyfrinair wedi'i amlygu mewn tor-data heb ei ddatrys
+        [two] Gyfrinair wedi'u hamlygu mewn tor-data heb eu datrys
+        [few] Cyfrinair wedi'u hamlygu mewn tor-data heb eu datrys
+        [many] Chyfrinair wedi'u hamlygu mewn tor-data heb eu datrys
+       *[other] Cyfrinair wedi'u hamlygu mewn tor-data heb eu datrys
+    }
+monitor-no-breaches-title = Newyddion da!
+monitor-no-breaches-description = Nid oes gennych unrhyw dor-data hysbys. Os bydd hynny'n newid, byddwn yn rhoi gwybod i chi.
+monitor-view-report-link = Gweld yr Adroddiad
+    .title = Datrys tor-data ar { -monitor-brand-short-name }
+monitor-breaches-unresolved-title = Datrys eich tor-data
+monitor-breaches-unresolved-description = Ar ôl adolygu manylion tor-data a chymryd camau i ddiogelu eich manylion, gallwch nodi fod eich tor-data wedi'u datrys.
+monitor-manage-breaches-link = Rheoli Tor-data
+    .title = Rheoli tor-data ar { -monitor-brand-short-name }
+monitor-breaches-resolved-title = Da! Rydych wedi datrys pob achos o dor-data hysbys.
+monitor-breaches-resolved-description = Os bydd eich e-bost yn ymddangos mewn unrhyw dor-data newydd, byddwn yn rhoi gwybod i chi.
+# Variables:
+# $numBreachesResolved (Number) - Number of breaches marked as resolved by the user on Monitor.
+# $numBreaches (Number) - Number of breaches in which a user's data was involved, detected by Monitor.
+monitor-partial-breaches-title =
+    { $numBreaches ->
+        [zero] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'u marcio fel wedi'u datrys
+        [one] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'i farcio fel wedi'i ddatrys
+        [two] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'u marcio fel wedi'u datrys
+        [few] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'u marcio fel wedi'u datrys
+        [many] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'u marcio fel wedi'u datrys
+       *[other] { $numBreachesResolved } allan o { $numBreaches } tor-data wedi'u marcio fel wedi'u datrys
+    }
+# Variables:
+# $percentageResolved (Number) - Percentage of breaches marked as resolved by a user on Monitor.
+monitor-partial-breaches-percentage = { $percentageResolved }% wedi'u cwblhau
+monitor-partial-breaches-motivation-title-start = Dechrau da!
+monitor-partial-breaches-motivation-title-middle = Daliwch ati!
+monitor-partial-breaches-motivation-title-end = Bron wedi ei wneud! Daliwch ati.
+monitor-partial-breaches-motivation-description = Datryswch weddill eich tor-data ar { -monitor-brand-short-name }
+monitor-resolve-breaches-link = Datrys Tor-data
+    .title = Datrys tor-data ar { -monitor-brand-short-name }
+
+## The title attribute is used to display the type of protection.
+## The aria-label is spoken by screen readers to make the visual graph accessible to blind users.
+##
+## Variables:
+##   $count (Number) - Number of specific trackers
+##   $percentage (Number) - Percentage this type of tracker contributes to the whole graph
+
+bar-tooltip-social =
+    .title = Tracwyr Cyfryngau Cymdeithasol
+    .aria-label =
+        { $count ->
+            [zero] { $count } tracwyr cyfryngau cymdeithasol ({ $percentage }%)
+            [one] { $count } traciwr cyfryngau cymdeithasol ({ $percentage }%)
+            [two] { $count } draciwr cyfryngau cymdeithasol ({ $percentage }%)
+            [few] { $count } traciwr cyfryngau cymdeithasol ({ $percentage }%)
+            [many] { $count } traciwr cyfryngau cymdeithasol ({ $percentage }%)
+           *[other] { $count } traciwr cyfryngau cymdeithasol ({ $percentage }%)
+        }
+bar-tooltip-cookie =
+    .title = Cwcis Tracio Traws-Gwefan
+    .aria-label =
+        { $count ->
+            [zero] { $count } cwcis tracio traws-gwefan ({ $percentage }%)
+            [one] { $count } cwci tracio traws-gwefan ({ $percentage }%)
+            [two] { $count } gwci tracio traws-gwefan ({ $percentage }%)
+            [few] { $count } cwci tracio traws-gwefan ({ $percentage }%)
+            [many] { $count } cwci tracio traws-gwefan ({ $percentage }%)
+           *[other] { $count } cwci tracio traws-gwefan ({ $percentage }%)
+        }
+bar-tooltip-tracker =
+    .title = Cynnwys Tracio
+    .aria-label =
+        { $count ->
+            [zero] { $count } cynnwys tracio ({ $percentage }%)
+            [one] { $count } cynnwys tracio ({ $percentage }%)
+            [two] { $count } cynnwys tracio ({ $percentage }%)
+            [few] { $count } cynnwys tracio ({ $percentage }%)
+            [many] { $count } cynnwys tracio ({ $percentage }%)
+           *[other] { $count } cynnwys tracio ({ $percentage }%)
+        }
+bar-tooltip-fingerprinter =
+    .title = Bysbrintwyr
+    .aria-label =
+        { $count ->
+            [zero] { $count } bysbrintwyr ({ $percentage }%)
+            [one] { $count } bysbrintwyr ({ $percentage }%)
+            [two] { $count } bysbrintwyr ({ $percentage }%)
+            [few] { $count } bysbrintwyr ({ $percentage }%)
+            [many] { $count } bysbrintwyr ({ $percentage }%)
+           *[other] { $count } bysbrintwyr ({ $percentage }%)
+        }
+bar-tooltip-cryptominer =
+    .title = Cryptogloddwyr
+    .aria-label =
+        { $count ->
+            [zero] { $count } cryptogloddwyr ({ $percentage }%)
+            [one] { $count } cryptogloddwyr ({ $percentage }%)
+            [two] { $count } cryptogloddwyr ({ $percentage }%)
+            [few] { $count } cryptogloddwyr ({ $percentage }%)
+            [many] { $count } cryptogloddwyr ({ $percentage }%)
+           *[other] { $count } cryptogloddwyr ({ $percentage }%)
+        }
diff --git a/l10n-cy/browser/browser/protectionsPanel.ftl b/l10n-cy/browser/browser/protectionsPanel.ftl
new file mode 100644
index 0000000000..539594c929
--- /dev/null
+++ b/l10n-cy/browser/browser/protectionsPanel.ftl
@@ -0,0 +1,98 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+protections-panel-sendreportview-error = Bu gwall wrth anfon yr adroddiad. Rhowch gynnig arall arni'n hwyrach.
+# A link shown when ETP is disabled for a site. Opens the breakage report subview when clicked.
+protections-panel-sitefixedsendreport-label = Gwefan wedi'i thrwsio? Anfon adroddiad
+
+## These strings are used to define the different levels of
+## Enhanced Tracking Protection.
+
+protections-popup-footer-protection-label-strict = Llym
+    .label = Llym
+protections-popup-footer-protection-label-custom = Cyfaddasu
+    .label = Cyfaddasu
+protections-popup-footer-protection-label-standard = Safonol
+    .label = Safonol
+
+##
+
+# The text a screen reader speaks when focused on the info button.
+protections-panel-etp-more-info =
+    .aria-label = Rhagor o wybodaeth am Ddiogelwch Rhag Tracio Uwch
+protections-panel-etp-on-header = Mae Diogelwch Uwch Rhag Tracio YMLAEN ar y wefan hon
+protections-panel-etp-off-header = Mae Diogelwch Uwch Rhag Tracio I FFWRDD ar y wefan hon
+# The link to be clicked to open the sub-panel view
+protections-panel-site-not-working = Gwefan ddim yn gweithio?
+# The heading/title of the sub-panel view
+protections-panel-site-not-working-view =
+    .title = Gwefan Ddim yn Gweithio?
+
+## The "Allowed" header also includes a "Why?" link that, when hovered, shows
+## a tooltip explaining why these items were not blocked in the page.
+
+protections-panel-not-blocking-why-label = Pam?
+protections-panel-not-blocking-why-etp-on-tooltip = Gallai rhwystro'r rhain dorri elfennau o rai gwefannau. Heb dracwyr, efallai na fydd rhai botymau, ffurflenni a meysydd mewngofnodi'n gweithio.
+protections-panel-not-blocking-why-etp-off-tooltip = Mae'r holl dracwyr ar y wefan hon wedi'u llwytho gan fod diogelu wedi'i ddiffodd.
+
+##
+
+protections-panel-no-trackers-found = Dim tracwyr hysbys i { -brand-short-name } wedi eu canfod ar y dudalen hon.
+protections-panel-content-blocking-tracking-protection = Cynnwys Tracio
+protections-panel-content-blocking-socialblock = Tracwyr Cyfryngau Cymdeithasol
+protections-panel-content-blocking-cryptominers-label = Cryptogloddwyr
+protections-panel-content-blocking-fingerprinters-label = Bysbrintwyr
+
+## In the protections panel, Content Blocking category items are in three sections:
+##   "Blocked" for categories being blocked in the current page,
+##   "Allowed" for categories detected but not blocked in the current page, and
+##   "None Detected" for categories not detected in the current page.
+##   These strings are used in the header labels of each of these sections.
+
+protections-panel-blocking-label = Rhwystrwyd
+protections-panel-not-blocking-label = Caniatawyd
+protections-panel-not-found-label = Heb Ganfod Dim
+
+##
+
+protections-panel-settings-label = Gosodiadau Diogelu
+# This should match the "appmenuitem-protection-dashboard-title" string in browser/appmenu.ftl.
+protections-panel-protectionsdashboard-label = Bwrdd Gwaith Diogelwch
+
+## In the Site Not Working? view, we suggest turning off protections if
+## the user is experiencing issues with any of a variety of functionality.
+
+# The header of the list
+protections-panel-site-not-working-view-header = Diffoddwch ddiogelu os rydych yn cael problemau gyda:
+# The list items, shown in a <ul>
+protections-panel-site-not-working-view-issue-list-login-fields = Meysydd mewngofnodi
+protections-panel-site-not-working-view-issue-list-forms = Ffurflenni
+protections-panel-site-not-working-view-issue-list-payments = Taliadau
+protections-panel-site-not-working-view-issue-list-comments = Sylwadau
+protections-panel-site-not-working-view-issue-list-videos = Fideos
+protections-panel-site-not-working-view-send-report = Anfon adroddiad
+
+##
+
+protections-panel-cross-site-tracking-cookies = Mae'r cwcis hyn yn eich dilyn o wefan i wefan i gasglu data am yr hyn rydych chi'n ei wneud ar-lein. Maen nhw'n cael eu gosod gan drydydd partïon fel hysbysebwyr a chwmnïau dadansoddol.
+protections-panel-cryptominers = Mae cryptogloddwyr yn defnyddio pŵer cyfrifiadurol eich system i gloddio arian digidol. Mae sgriptiau cryptogloddio yn gwagio eich batri, arafu eich cyfrifiadur, a gall gynyddu eich bil trydan.
+protections-panel-fingerprinters = Mae bysbrintwyr yn casglu gosodiadau o'ch porwr a'ch cyfrifiadur i greu proffil ohonoch. Gan ddefnyddio'r olion bys digidol hwn, mae nhw'n gallu'ch tracio ar draws gwahanol wefannau.
+protections-panel-tracking-content = Gall gwefannau lwytho hysbysebion allanol, fideos a chynnwys eraill sy'n cynnwys cod tracio. Gall rhwystro cynnwys tracio helpu gwefannau i lwytho'n gynt, ond efallai na fydd rhai botymau, ffurflenni a meysydd mewngofnodi'n gweithio.
+protections-panel-social-media-trackers = Mae rhwydweithiau cymdeithasol yn gosod tracwyr ar wefannau eraill i ddilyn yr hyn rydych chi'n ei wneud, ei weld, a'i wylio ar-lein. Mae hyn yn caniatáu i gwmnïau cyfryngau cymdeithasol ddysgu mwy amdanoch chi y tu hwnt i'r hyn rydych chi'n ei rannu ar eich proffiliau cyfryngau cymdeithasol.
+protections-panel-content-blocking-manage-settings =
+    .label = Rheoli Gosodiadau Diogelu
+    .accesskey = R
+protections-panel-content-blocking-breakage-report-view =
+    .title = Adrodd ar Wefan wedi Torri
+protections-panel-content-blocking-breakage-report-view-description = Gall rhwystro cynnwys achosi problemau gyda rai gwefannau. Pan fyddwch yn cyflwyno adroddiad ar broblemau, byddwch yn helpu gwneud { -brand-short-name } yn well i bawb. (Bydd hyn yn anfon yr URL yn ogystal â gwybodaeth am osodiadau eich porwr i Mozilla. <label data-l10n-name="learn-more">Dysgu rhagor</label>
+protections-panel-content-blocking-breakage-report-view-collection-url = URL
+protections-panel-content-blocking-breakage-report-view-collection-url-label =
+    .aria-label = URL
+protections-panel-content-blocking-breakage-report-view-collection-comments = Dewisol: Disgrifiwch y broblem
+protections-panel-content-blocking-breakage-report-view-collection-comments-label =
+    .aria-label = Dewisol: Disgrifiwch y broblem
+protections-panel-content-blocking-breakage-report-view-cancel =
+    .label = Diddymu
+protections-panel-content-blocking-breakage-report-view-send-report =
+    .label = Anfon Adroddiad
diff --git a/l10n-cy/browser/browser/safeMode.ftl b/l10n-cy/browser/browser/safeMode.ftl
new file mode 100644
index 0000000000..77a9877a63
--- /dev/null
+++ b/l10n-cy/browser/browser/safeMode.ftl
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+safe-mode-window =
+    .title = Modd Diogel { -brand-short-name }
+    .style = max-width: 400px
+start-safe-mode =
+    .label = Cychwyn yn y Modd Diogel
+refresh-profile =
+    .label = Adnewyddu { -brand-short-name }
+safe-mode-description = Modd arbennig o fewn { -brand-short-name } yw'r Modd Diogel y mae modd ei ddefnyddio i ddatrys problemau.
+safe-mode-description-details = Gall fod eich ychwanegion a'ch gosodiadau cyfaddas fod wedi eu analluogi dros dro ac nad yw nodweddion { -brand-short-name } yn ymddwyn fel maen nhw'n gwneud ar hyn o bryd.
+refresh-profile-instead = Gallwch hepgor datrys problemau a cheisio adnewyddu { -brand-short-name }.
+# Shown on the safe mode dialog after multiple startup crashes. 
+auto-safe-mode-description = Caeodd { -brand-short-name } yn annisgwyl wrth gychwyn. Efallai fod hyn o ganlyniad i ychwanegyn neu anhawster arall. Mae modd ceisio datrys y broblem o fewn y Modd Diogel.
diff --git a/l10n-cy/browser/browser/safebrowsing/blockedSite.ftl b/l10n-cy/browser/browser/safebrowsing/blockedSite.ftl
new file mode 100644
index 0000000000..5c8532bc23
--- /dev/null
+++ b/l10n-cy/browser/browser/safebrowsing/blockedSite.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+safeb-blocked-phishing-page-title = Gwefan twyllodrus o'ch blaen
+safeb-blocked-malware-page-title = Gall mynd i'r wefan hon wneud drwg i'ch cyfrifiadur
+safeb-blocked-unwanted-page-title = Gall fod y wefan o'ch blaen yn cynnwys rhaglenni niweidiol
+safeb-blocked-harmful-page-title = Gall fod y wefan yn cynnwys drwgwar
+safeb-blocked-phishing-page-short-desc = Mae { -brand-short-name } wedi rhwystro'r dudalen hon gan y gallai geisio eich twyllo i wneud rhywbeth peryglus fel gosod meddalwedd neu ddatgelu manylion personol fel cyfrineiriau neu gardiau credyd.
+safeb-blocked-malware-page-short-desc = Mae { -brand-short-name } wedi atal y dudalen hon gan y gall geisio gosod meddalwedd drwg er mwyn drwyn neu ddileu gwybodaeth bersonol ar eich cyfrifiadur.
+safeb-blocked-unwanted-page-short-desc = Mae { -brand-short-name } wedi rhwystro'r dudalen hon gan y gall geisio eich twyllo i osod rhaglenni gall fod yn niweidiol i'ch profiad pori (e.e. drwy newid eich tudalen cartref neu ddangos hysbysebion ychwanegol ar wefannau rydych yn ymweld â nhw).
+safeb-blocked-harmful-page-short-desc = Mae { -brand-short-name } wedi rhwystro'r dudalen hon gan y gall geisio gosod apiau peryglus sy'n dwyn neu ddileu eich manylion (e.e., lluniau, cyfrineiriau, negeseuon a chardiau credyd).
+safeb-palm-advisory-desc = Cyngor yn cael ei ddarparu gan <a data-l10n-name='advisory_provider'>{ $advisoryname }</a>.
+safeb-palm-accept-label = Nôl
+safeb-palm-see-details-label = Gweld manylion
+safeb-blocked-phishing-page-error-desc-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan twyllodrus</a>. Gallwch <a data-l10n-name='report_detection'>adrodd ar anhawster canfod</a> neu <a data-l10n-name='ignore_warning_link'>anwybyddu'r perygl</a> a mynd i'r wefan anniogel hon.
+safeb-blocked-phishing-page-error-desc-no-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan twyllodrus</a>. Gallwch <a data-l10n-name='report_detection'>adrodd ar anhawster canfod</a>.
+safeb-blocked-phishing-page-learn-more = Mae rhagor o wybodaeth am wefannau twyllodrus a physgota yn <a data-l10n-name='learn_more_link'>www.antiphishing.org</a>. A Diogelwch rhag Pysgota a Drwgwar { -brand-short-name } yn <a data-l10n-name='firefox_support'>support.mozilla.org</a>.
+safeb-blocked-malware-page-error-desc-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd maleisus</a>. Gallwch <a data-l10n-name='report_detection'>adrodd ar anhawster canfod</a> neu <a data-l10n-name='ignore_warning_link'>anwybyddu'r perygl</a> a mynd i'r wefan anniogel hon.
+safeb-blocked-malware-page-error-desc-no-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd maleisus</a>. Gallwch <a data-l10n-name='report_detection'>adrodd ar anhawster canfod</a>.
+safeb-blocked-malware-page-learn-more = Mae rhagor o wybodaeth am gynnwys gwe faleisus gan gynnwys firysau a drwgwar eraill a sut i ddiogelu eich cyfrifiadur yn <a data-l10n-name='learn_more_link'>StopBadware.org</a>. Hefyd, mae gwybodaeth am Ddiogelwch Pysgota a Drwgwar { -brand-short-name } yn <a data-l10n-name='firefox_support'>support.mozilla.org</a>.
+safeb-blocked-malware-page-error-desc-override-sumo = Mae <span data-l10n-name='sitename'>{ $sitename }</span> y hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd maleisus</a>. Gallwch <a data-l10n-name='ignore_warning_link'>anwybyddu'r perygl</a> a mynd i'r wefan anniogel hon.
+safeb-blocked-malware-page-error-desc-no-override-sumo = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd maleisus</a>.
+safeb-blocked-malware-page-learn-more-sumo = Dysgu rhagor am Ddiogelwch rhag Pysgota a Drwgwar { -brand-short-name } yn <a data-l10n-name='firefox_support'> support.mozilla.org </a>.
+safeb-blocked-unwanted-page-error-desc-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> y hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd niweidiol</a>. Gallwch <a data-l10n-name='ignore_warning_link'>anwybyddu'r perygl</a> a mynd i'r wefan anniogel hon.
+safeb-blocked-unwanted-page-error-desc-no-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys meddalwedd niweidiol</a>.
+safeb-blocked-unwanted-page-learn-more = Mae rhagor o wybodaeth am feddalwedd niweidiol a digroeso yn <a data-l10n-name='learn_more_link'>Polisi Meddalwedd Digroeso</a>. A Diogelwch rhag Pysgota a Drwgwar { -brand-short-name } yn <a data-l10n-name='firefox_support'>support.mozilla.org</a>.
+safeb-blocked-harmful-page-error-desc-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel gwefan sy'n cynnwys rhaglen sydd o bosib yn niweidiol</a>. Gallwch <a data-l10n-name='ignore_warning_link'>anwybyddu'r perygl</a> a mynd i'r wefan anniogel hon.
+safeb-blocked-harmful-page-error-desc-no-override = Mae <span data-l10n-name='sitename'>{ $sitename }</span> yn hysbys <a data-l10n-name='error_desc_link'>fel wefan sy'n cynnwys rhaglen sydd o bosib yn niweidiol</a>.
+safeb-blocked-harmful-page-learn-more = Mae rhagor o wybodaeth am Ddiogelwch Rhag Pysgota a Drwgwar { -brand-short-name } yn <a data-l10n-name='firefox_support'>support.mozilla.org</a>.
+safeb-palm-notdeceptive =
+    .label = Nid yw hon yn wefan twyllodrus…
+    .accesskey = t
diff --git a/l10n-cy/browser/browser/sanitize.ftl b/l10n-cy/browser/browser/sanitize.ftl
new file mode 100644
index 0000000000..06f0384db8
--- /dev/null
+++ b/l10n-cy/browser/browser/sanitize.ftl
@@ -0,0 +1,110 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+sanitize-prefs =
+    .title = Gosodiadau Clirio Hanes
+    .style = width: 34em
+
+sanitize-prefs-style =
+    .style = width: 17em
+
+dialog-title =
+    .title = Clirio'r Hanes Diweddar
+    .style = width: 34em
+
+# When "Time range to clear" is set to "Everything", this message is used for the
+# title instead of dialog-title.
+dialog-title-everything =
+    .title = Clirio'r Holl Hanes
+    .style = width: 34em
+
+clear-data-settings-label = Pan fyddai'n gadael { -brand-short-name } dylai glirio popeth yn awtomatig
+
+## clear-time-duration-prefix is followed by a dropdown list, with
+## values localized using clear-time-duration-value-* messages.
+## clear-time-duration-suffix is left empty in English, but can be
+## used in other languages to change the structure of the message.
+##
+## This results in English:
+## Time range to clear: (Last Hour, Today, etc.)
+
+clear-time-duration-prefix =
+    .value = Cyfnod i'w glirio:{ " " }
+    .accesskey = C
+
+clear-time-duration-value-last-hour =
+    .label = Awr Diwethaf
+
+clear-time-duration-value-last-2-hours =
+    .label = Dwy Awr Diwethaf
+
+clear-time-duration-value-last-4-hours =
+    .label = Pedair Awr Diwethaf
+
+clear-time-duration-value-today =
+    .label = Heddiw
+
+clear-time-duration-value-everything =
+    .label = Popeth
+
+clear-time-duration-suffix =
+    .value = { "" }
+
+## These strings are used as section comments and checkboxes
+## to select the items to remove
+
+history-section-label = Hanes
+
+item-history-and-downloads =
+    .label = Hanes Pori a Llwytho i Lawr
+    .accesskey = H
+
+item-cookies =
+    .label = Cwcis
+    .accesskey = w
+
+item-active-logins =
+    .label = Mewngofnodion Gweithredol
+    .accesskey = M
+
+item-cache =
+    .label = Storfa Dros Dro
+    .accesskey = S
+
+item-form-search-history =
+    .label = Hanes Ffurflenni a Chwilio
+    .accesskey = F
+
+data-section-label = Data
+
+item-site-preferences =
+    .label = Dewisiadau'r Wefan
+    .accesskey = D
+
+item-offline-apps =
+    .label = Data Gwefan All-lein
+    .accesskey = D
+
+sanitize-everything-undo-warning = Nid oes modd dadwneud y weithred.
+
+window-close =
+    .key = w
+
+sanitize-button-ok =
+    .label = Clirio Nawr
+
+# The label for the default button between the user clicking it and the window
+# closing.  Indicates the items are being cleared.
+sanitize-button-clearing =
+    .label = Clirio
+
+# Warning that appears when "Time range to clear" is set to "Everything" in Clear
+# Recent History dialog, provided that the user has not modified the default set
+# of history items to clear.
+sanitize-everything-warning = Bydd yr holl hanes yn cael ei glirio.
+
+# Warning that appears when "Time range to clear" is set to "Everything" in Clear
+# Recent History dialog, provided that the user has modified the default set of
+# history items to clear.
+sanitize-selected-warning = Bydd yr holl eitemau a ddewiswyd yn cael eu clirio.
diff --git a/l10n-cy/browser/browser/screenshots.ftl b/l10n-cy/browser/browser/screenshots.ftl
new file mode 100644
index 0000000000..1514a2fa6f
--- /dev/null
+++ b/l10n-cy/browser/browser/screenshots.ftl
@@ -0,0 +1,47 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+screenshots-context-menu = Cymryd Llun Sgrin Screenshot
+
+screenshots-my-shots-button = Fy Lluniau Sgrin
+screenshots-instructions = Llusgwch neu glicio ar y dudalen i ddewis adran. Pwyso ESC i ddiddymu.
+screenshots-cancel-button = Diddymu
+screenshots-save-visible-button = Cadw'r gweladwy
+screenshots-save-page-button = Cadw tudalen lawn
+screenshots-download-button = Llwytho i Lawr
+screenshots-download-button-tooltip = Llwytho i lawr llun sgrin
+screenshots-copy-button = Copïo
+screenshots-copy-button-tooltip = Copïo llun sgrin i'r clipfwrdd
+
+screenshots-meta-key =
+    { PLATFORM() ->
+        [macos] ⌘
+       *[other] Ctrl
+    }
+screenshots-notification-link-copied-title = Dolen wedi ei Chadw
+screenshots-notification-link-copied-details = Mae'r ddolen i'ch llun wedi ei gopïo i'r clipfwrdd. Pwyswch { screenshots-meta-key }-V i'w ludo.
+
+screenshots-notification-image-copied-title = Copïwyd y Llun
+screenshots-notification-image-copied-details = Mae eich llun wedi ei gopïo i'r clipfwrdd. Pwyswch { screenshots-meta-key }-V i'w ludo.
+
+screenshots-request-error-title = Ddim yn gweithio.
+screenshots-request-error-details = Ymddiheuriadau! Nid oedd modd cadw eich llun. Ceisiwch eto'n hwyrach.
+
+screenshots-connection-error-title = Nid oes modd i ni gysylltu a'ch lluniau sgrin.
+screenshots-connection-error-details = Gwiriwch eich cysylltiad Rhyngrwyd. Os ydych yn gallu cysylltu â'r Rhyngrwyd, efallai bod anhawster dros dro gyda gwasanaeth lluniau sgrin, { -screenshots-brand-name }.
+
+screenshots-login-error-details = Nid oedd modd i ni gadw eich llun gan fod yna anhawster gyda gwasanaeth { -screenshots-brand-name }. Ceisiwch eto'n hwyrach.
+
+screenshots-unshootable-page-error-title = Nid oes modd tynnu llun sgrin o'r dudalen.
+screenshots-unshootable-page-error-details = Nid yw hwn yn dudalen Gwe safonol, felly does dim modd tynnu llun sgrin ohono.
+
+screenshots-self-screenshot-error-title = Nid oes modd cymryd llun o dudalen lluniau sgrin { -screenshots-brand-name }!
+
+screenshots-empty-selection-error-title = Mae eich dewis yn rhy fach
+
+screenshots-private-window-error-title = Mae { -screenshots-brand-name } wedi ei analluogi yn y Modd Pori Preifat
+screenshots-private-window-error-details = Ymddiheuriadau am yr anhwylustod. Rydym yn gweithio ar y nodwedd hwn ar gyfer fersiynau'r dyfodol.
+
+screenshots-generic-error-title = Www! Mae { -screenshots-brand-name } wedi mynd yn hurt.
+screenshots-generic-error-details = Nid ydym yn gwybod beth sydd wedi ddigwydd. Ceisiwch eto neu dynnu llun o dudalen wahanol?
diff --git a/l10n-cy/browser/browser/search.ftl b/l10n-cy/browser/browser/search.ftl
new file mode 100644
index 0000000000..3cdd25079b
--- /dev/null
+++ b/l10n-cy/browser/browser/search.ftl
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## These strings are used for errors when installing OpenSearch engines, e.g.
+## via "Add Search Engine" on the address bar or search bar.
+## Variables
+## $location-url (String) - the URL of the OpenSearch engine that was attempted to be installed.
+
+opensearch-error-duplicate-title = Gwall Gosod
+opensearch-error-duplicate-desc = Methodd { -brand-short-name } â gosod yr ategyn chwilio o "{ $location-url }" gan fod peiriant chwilio sydd â'r un enw yn bodoli'n barod.
+opensearch-error-format-title = Fformat Annilys
+opensearch-error-format-desc = Nid yw { -brand-short-name } yn gallu gosod y peiriant chwilio o { $location-url }
+opensearch-error-download-title = Gwall llwytho i lawr
+opensearch-error-download-desc = Methodd { -brand-short-name } â llwytho i lawr yr ategyn chwilio o: { $location-url }
+
+##
+
diff --git a/l10n-cy/browser/browser/setDesktopBackground.ftl b/l10n-cy/browser/browser/setDesktopBackground.ftl
new file mode 100644
index 0000000000..dfcc07da23
--- /dev/null
+++ b/l10n-cy/browser/browser/setDesktopBackground.ftl
@@ -0,0 +1,40 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+set-desktop-background-window =
+    .title = Gosod Cefndir Bwrdd Gwaith
+
+set-desktop-background-accept =
+    .label = Gosod Cefndir Bwrdd Gwaith
+
+open-desktop-prefs =
+    .label = Dewisiadau'r Bwrdd Gwaith Agored
+
+set-background-preview-unavailable = Dim rhagolwg ar gael
+
+# This refers to the wallpaper "spanning" multiple monitors when the
+# user has more than one. Only some of the entire image will be on
+# each monitor. This should ideally match the wording in Windows' own
+# Desktop Background settings page.
+set-background-span =
+    .label = Ymestyn
+
+set-background-color = Lliw:
+
+set-background-position = Safle:
+
+set-background-tile =
+    .label = Teilio
+
+set-background-center =
+    .label = Canol
+
+set-background-stretch =
+    .label = Estyn
+
+set-background-fill =
+    .label = Llanw
+
+set-background-fit =
+    .label = Ffitio
diff --git a/l10n-cy/browser/browser/sidebarMenu.ftl b/l10n-cy/browser/browser/sidebarMenu.ftl
new file mode 100644
index 0000000000..c059b621ee
--- /dev/null
+++ b/l10n-cy/browser/browser/sidebarMenu.ftl
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+sidebar-menu-bookmarks =
+    .label = Nodau Tudalen
+
+sidebar-menu-history =
+    .label = Hanes
+
+sidebar-menu-synced-tabs =
+    .label = Tabiau wedi'u Cydweddu
+
+sidebar-menu-close =
+    .label = Cau'r Bar Ochr
diff --git a/l10n-cy/browser/browser/sync.ftl b/l10n-cy/browser/browser/sync.ftl
new file mode 100644
index 0000000000..41abf9b395
--- /dev/null
+++ b/l10n-cy/browser/browser/sync.ftl
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+fxa-toolbar-sync-syncing =
+    .label = Cydweddu…
+fxa-toolbar-sync-syncing-tabs =
+    .label = Cydweddu Tabiau…
+sync-disconnect-dialog-title = Datgysylltu { -sync-brand-short-name }?
+sync-disconnect-dialog-body = Bydd { -brand-product-name } yn peidio cydweddu eich cyfrif ond ni fydd yn dileu eich data pori ar y ddyfais hon.
+fxa-disconnect-dialog-title = Datgysylltu { -brand-product-name }?
+fxa-disconnect-dialog-body = Bydd { -brand-product-name } yn datgysylltu o'ch cyfrif ond ni fydd yn dileu dim o'ch data pori ar y ddyfais hon.
+sync-disconnect-dialog-button = Datgysylltu
+fxa-signout-dialog-heading = Allgofnodi o { -fxaccount-brand-name }
+fxa-signout-dialog-body = Bydd data wedi'i gydweddu'n aros yn eich cyfrif.
+fxa-signout-checkbox =
+    .label = Dileu data o'r ddyfais hon (mewngofnodion, cyfrineiriau, hanes, nodau tudalen, ac ati).
+fxa-signout-dialog =
+    .title = Allgofnodi o { -fxaccount-brand-name }
+    .style = min-width: 375px;
+    .buttonlabelaccept = Allgofnodi
diff --git a/l10n-cy/browser/browser/syncedTabs.ftl b/l10n-cy/browser/browser/syncedTabs.ftl
new file mode 100644
index 0000000000..f49586900b
--- /dev/null
+++ b/l10n-cy/browser/browser/syncedTabs.ftl
@@ -0,0 +1,43 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+synced-tabs-sidebar-title = Tabiau wedi'u Cydweddu
+synced-tabs-sidebar-noclients-subtitle = Hoffech chi weld eich tabiau o ddyfeisiau eraill yma?
+synced-tabs-sidebar-intro = Gweld rhestr o dabiau o'ch dyfeisiau eraill.
+synced-tabs-sidebar-unverified = Mae angen i'ch cyfrif cael ei gwirio.
+synced-tabs-sidebar-notabs = Dim tabiau agored
+synced-tabs-sidebar-openprefs = Agor Dewisiadau { -sync-brand-short-name }
+synced-tabs-sidebar-tabsnotsyncing = Cychwynnwch gydweddu tabiau er mwyn gweld rhestr o dabiau o'ch dyfeisiau eraill.
+synced-tabs-sidebar-connect-another-device = Cysylltu Dyfais Arall
+synced-tabs-sidebar-search =
+    .placeholder = Chwilio tabiau wedi eu cydweddu
+synced-tabs-context-open =
+    .label = Agor
+    .accesskey = g
+synced-tabs-context-open-in-new-tab =
+    .label = Agor mewn Tab Newydd
+    .accesskey = w
+synced-tabs-context-open-in-new-window =
+    .label = Agor mewn Ffenestr Newydd
+    .accesskey = F
+synced-tabs-context-open-in-new-private-window =
+    .label = Agor Dolen mewn Ffenestr Breifat Newydd
+    .accesskey = N
+synced-tabs-context-bookmark-single-tab =
+    .label = Gosod Nod Tudalen i'r Tab Hwn…
+    .accesskey = N
+synced-tabs-context-copy =
+    .label = Copïo
+    .accesskey = C
+synced-tabs-context-open-all-in-tabs =
+    .label = Agor Popeth mewn Tabiau
+    .accesskey = A
+synced-tabs-context-manage-devices =
+    .label = Rheoli Dyfeisiadau…
+    .accesskey = D
+synced-tabs-context-sync-now =
+    .label = Cydweddu Nawr
+    .accesskey = y
+fxa-sign-in = Mewngofnodi i { -sync-brand-short-name }
+turn-on-sync = Cychwyn { -sync-brand-short-name }
diff --git a/l10n-cy/browser/browser/tabContextMenu.ftl b/l10n-cy/browser/browser/tabContextMenu.ftl
new file mode 100644
index 0000000000..0e5cf4ace6
--- /dev/null
+++ b/l10n-cy/browser/browser/tabContextMenu.ftl
@@ -0,0 +1,110 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+reload-tab =
+    .label = Ail lwytho Tab
+    .accesskey = A
+select-all-tabs =
+    .label = Dewis Pob Tab
+    .accesskey = D
+duplicate-tab =
+    .label = Dyblygu Tab
+    .accesskey = D
+duplicate-tabs =
+    .label = Tabiau Dyblyg
+    .accesskey = D
+close-tabs-to-the-end =
+    .label = Cau Tabiau i'r Dde
+    .accesskey = D
+close-other-tabs =
+    .label = Cau Tabiau Eraill
+    .accesskey = C
+reload-tabs =
+    .label = Ail-lwytho Tabiau
+    .accesskey = A
+pin-tab =
+    .label = Pinio Tab
+    .accesskey = P
+unpin-tab =
+    .label = Dadbinio Tab
+    .accesskey = D
+pin-selected-tabs =
+    .label = Pinio Tabiau
+    .accesskey = P
+unpin-selected-tabs =
+    .label = Dadbinio Tabiau
+    .accesskey = b
+bookmark-selected-tabs =
+    .label = Gosod Nod Tudalen i'r Tabiau…
+    .accesskey = T
+bookmark-tab =
+    .label = Gosod Nod Tudalen i'r Tab
+    .accesskey = N
+reopen-in-container =
+    .label = Ail agor mewn Cynhwysydd
+    .accesskey = A
+move-to-start =
+    .label = Symud i'r Cychwyn
+    .accesskey = C
+move-to-end =
+    .label = Symud i'r Diwedd
+    .accesskey = D
+move-to-new-window =
+    .label = Symud i Ffenestr Newydd
+    .accesskey = N
+tab-context-close-multiple-tabs =
+    .label = Cau Tabiau Lluosog
+    .accesskey = L
+
+## Variables:
+##  $tabCount (Number): the number of tabs that are affected by the action.
+
+tab-context-undo-close-tabs =
+    .label =
+        { $tabCount ->
+            [1] Dadwneud Cau Tabiau
+            [zero] Dadwneud Cau Tabiau
+            [one] Dadwneud Cau Tab
+            [two] Dadwneud Cau Tabiau
+            [few] Dadwneud Cau Tabiau
+            [many] Dadwneud Cau Tabiau
+           *[other] Dadwneud Cau Tabiau
+        }
+    .accesskey = D
+close-tab =
+    .label = Cau Tab
+    .accesskey = C
+close-tabs =
+    .label = Cau Tabiau
+    .accesskey = T
+move-tabs =
+    .label = Symud Tabiau
+    .accesskey = y
+move-tab =
+    .label = Symud Tab
+    .accesskey = y
+tab-context-close-tabs =
+    .label =
+        { $tabCount ->
+            [1] Cau Tab
+            [zero] Cau Tab
+            [one] Cau Tab
+            [two] Cau Tab
+            [few] Cau Tab
+            [many] Cau Tab
+           *[other] Cau Tab
+        }
+    .accesskey = C
+tab-context-move-tabs =
+    .label =
+        { $tabCount ->
+            [1] Symud Tab
+            [zero] Symud Tab
+            [one] Symud Tab
+            [two] Symud Tab
+            [few] Symud Tab
+            [many] Symud Tab
+           *[other] Symud Tab
+        }
+    .accesskey = S
diff --git a/l10n-cy/browser/browser/toolbarContextMenu.ftl b/l10n-cy/browser/browser/toolbarContextMenu.ftl
new file mode 100644
index 0000000000..d4ab374401
--- /dev/null
+++ b/l10n-cy/browser/browser/toolbarContextMenu.ftl
@@ -0,0 +1,79 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+toolbar-context-menu-reload-selected-tab =
+    .label = Ail Lwytho'r Tab Hwn
+    .accesskey = A
+toolbar-context-menu-reload-selected-tabs =
+    .label = Ail Lwytho'r Tabiau Hyn
+    .accesskey = A
+toolbar-context-menu-bookmark-selected-tab =
+    .label = Gosod Nod Tudalen i'r Tab Hwn…
+    .accesskey = T
+toolbar-context-menu-bookmark-selected-tabs =
+    .label = Gosod Nod Tudalen i'r Tabiau Hyn…
+    .accesskey = T
+toolbar-context-menu-select-all-tabs =
+    .label = Dewis Pob Tab
+    .accesskey = D
+toolbar-context-menu-undo-close-tabs =
+    .label =
+        { $tabCount ->
+            [1] Dadwneud Cau Tab
+            [zero] Dadwneud Cau Tabiau
+            [one] Dadwneud Cau Tab
+            [two] Dadwneud Cau Tabiau
+            [few] Dadwneud Cau Tabiau
+            [many] Dadwneud Cau Tabiau
+           *[other] Dadwneud Cau Tabiau
+        }
+    .accesskey = C
+toolbar-context-menu-manage-extension =
+    .label = Rheoli Estyniad
+    .accesskey = E
+toolbar-context-menu-remove-extension =
+    .label = Tynnu'r Estyniad
+    .accesskey = T
+# This label is used in the extensions toolbar buttons context menus,
+# a user can use this command to submit to Mozilla an abuse report
+# related to that extension. "Report" is a verb.
+toolbar-context-menu-report-extension =
+    .label = Adrodd ar yr Estyniad
+    .accesskey = A
+# Can appear on the same context menu as menubarCmd ("Menu Bar") and
+# personalbarCmd ("Bookmarks Toolbar"), so they should have different
+# access keys.
+toolbar-context-menu-pin-to-overflow-menu =
+    .label = Pinio i'r Ddewislen Ychwanegol
+    .accesskey = P
+toolbar-context-menu-auto-hide-downloads-button =
+    .label = Awtoguddio yn y Bar Offer
+    .accesskey = A
+toolbar-context-menu-remove-from-toolbar =
+    .label = Tynnu o'r Bar Offer
+    .accesskey = T
+toolbar-context-menu-view-customize-toolbar =
+    .label = Cyfaddasu…
+    .accesskey = y
+toolbar-context-menu-bookmarks-toolbar-always-show =
+    .label = Bob tro
+    .accesskey = B
+toolbar-context-menu-bookmarks-toolbar-never-show =
+    .label = Byth
+    .accesskey = y
+toolbar-context-menu-bookmarks-toolbar-on-new-tab =
+    .label = Dim ond ar Dab Newydd
+    .accesskey = D
+toolbar-context-menu-bookmarks-toolbar-always-show-2 =
+    .label = Dangos Bob Tro
+    .accesskey = D
+toolbar-context-menu-bookmarks-toolbar-never-show-2 =
+    .label = Peidio Dangos Byth
+    .accesskey = P
+toolbar-context-menu-bookmarks-toolbar-on-new-tab-2 =
+    .label = Dangos ar Dab Newydd yn Unig
+    .accesskey = U
+toolbar-context-menu-bookmarks-show-other-bookmarks =
+    .label = Dangos Nodau Tudalen Eraill
+    .accesskey = N
diff --git a/l10n-cy/browser/browser/touchbar/touchbar.ftl b/l10n-cy/browser/browser/touchbar/touchbar.ftl
new file mode 100644
index 0000000000..dfbf66b719
--- /dev/null
+++ b/l10n-cy/browser/browser/touchbar/touchbar.ftl
@@ -0,0 +1,38 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Strings in this file are used to localize button titles displayed on the 
+# MacBook Touch Bar.
+back = Nôl
+forward = Ymlaen
+reload = Ail-lwytho
+home = Cartref
+fullscreen = Sgrin Lawn
+touchbar-fullscreen-exit = Gadael Sgrin Lawn
+find = Canfod
+new-tab = Tab newydd
+add-bookmark = Ychwanegu nod tudalen
+reader-view = Golwg Darllen
+# Meant to match the string displayed in an empty URL bar.
+open-location = Chwilio neu rhoi cyfeiriad
+share = Rhannu
+close-window = Cau Ffenestr
+open-sidebar = Barrau Ochr
+
+# This string describes shortcuts for search.
+search-popover = Chwilio llwybrau byr
+# Describes searches limited to a specific scope
+# (e.g. searching only in history).
+search-search-in = Chwilio yn:
+
+## Various categories of shortcuts for search.
+
+search-bookmarks = Nodau Tudalen
+search-history = Hanes
+search-opentabs = Tabiau Agored
+search-tags = Tagiau
+search-titles = Teitlau
+
+##
+
diff --git a/l10n-cy/browser/browser/webrtcIndicator.ftl b/l10n-cy/browser/browser/webrtcIndicator.ftl
new file mode 100644
index 0000000000..1786291914
--- /dev/null
+++ b/l10n-cy/browser/browser/webrtcIndicator.ftl
@@ -0,0 +1,40 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# Note: This is currently placed under browser/base/content so that we can
+# get the strings to appear without having our localization community need
+# to go through and translate everything. Once these strings are ready for
+# translation, we'll move it to the locales folder.
+
+# This string is used so that the window has a title in tools that enumerate/look for window
+# titles. It is not normally visible anywhere.
+webrtc-indicator-title = { -brand-short-name } - Dangosydd rhannu
+webrtc-sharing-window = Rydych yn rhannu ffenestr rhaglen arall.
+webrtc-sharing-browser-window = Rydych chi'n rhannu { -brand-short-name }.
+webrtc-sharing-screen = Rydych yn rhannu'ch sgrin gyfan.
+webrtc-stop-sharing-button = Peidio Rhannu
+webrtc-microphone-button =
+    .title = Mae'ch meicroffon yn cael ei rannu. Cliciwch i reoli rhannu.
+webrtc-camera-button =
+    .title = Mae'ch camera yn cael ei rannu. Cliciwch i reoli rhannu.
+webrtc-microphone-unmuted =
+    .title = Diffodd y meicroffon
+webrtc-microphone-muted =
+    .title = Troi'r meicroffon ymlaen
+webrtc-camera-unmuted =
+    .title = Diffodd y meicroffon
+webrtc-camera-muted =
+    .title = Troi'r camera ymlaen
+webrtc-minimize =
+    .title = Lleihau'r dangosydd
+# This string will display as a tooltip on supported systems where we show
+# device sharing state in the OS notification area. We do not use these strings
+# on macOS, as global menu bar items do not have native tooltips.
+webrtc-camera-system-menu =
+    .label = Rydych yn rhannu'ch camera. Cliciwch i reoli rhannu.
+webrtc-microphone-system-menu =
+    .label = Rydych yn rhannu'ch meicroffon. Cliciwch i reoli rhannu.
+webrtc-screen-system-menu =
+    .label = Rydych yn rhannu ffenestr neu sgrin. Cliciwch i reoli rhannu.
diff --git a/l10n-cy/browser/chrome/browser-region/region.properties b/l10n-cy/browser/chrome/browser-region/region.properties
new file mode 100644
index 0000000000..474756632f
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser-region/region.properties
@@ -0,0 +1,29 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: REVIEW_REQUIRED
+# Please do not commit any changes to this file without a review from
+# the l10n-drivers team (this includes en-US). In order to get one,
+# please file a bug, add the "productization" keyword and CC l10n@mozilla.com.
+
+# increment this number when anything gets changed in the list below.  This will
+# cause Firefox to re-read these prefs and inject any new handlers into the 
+# profile database.  Note that "new" is defined as "has a different URL"; this
+# means that it's not possible to update the name of existing handler, so 
+# don't make any spelling errors here.
+gecko.handlerService.defaultHandlersVersion=4
+
+# The default set of protocol handlers for mailto:
+gecko.handlerService.schemes.mailto.0.name=Yahoo! Mail
+gecko.handlerService.schemes.mailto.0.uriTemplate=https://compose.mail.yahoo.com/?To=%s 
+gecko.handlerService.schemes.mailto.1.name=Google Mail
+gecko.handlerService.schemes.mailto.1.uriTemplate=https://mail.google.com/mail/?extsrc=mailto&url=%s
+
+# The default set of protocol handlers for irc:
+gecko.handlerService.schemes.irc.0.name=Mibbit
+gecko.handlerService.schemes.irc.0.uriTemplate=https://www.mibbit.com/?url=%s
+
+# The default set of protocol handlers for ircs:
+gecko.handlerService.schemes.ircs.0.name=Mibbit
+gecko.handlerService.schemes.ircs.0.uriTemplate=https://www.mibbit.com/?url=%s
diff --git a/l10n-cy/browser/chrome/browser/accounts.properties b/l10n-cy/browser/chrome/browser/accounts.properties
new file mode 100644
index 0000000000..04b10d34f4
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/accounts.properties
@@ -0,0 +1,129 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (reconnectDescription) - %S = Email address of user's Firefox Account
+reconnectDescription = Ailgysylltu %S
+
+# LOCALIZATION NOTE (verifyDescription) - %S = Email address of user's Firefox Account
+verifyDescription = Dilysu %S
+
+# These strings are shown in a desktop notification after the
+# user requests we resend a verification email.
+verificationSentTitle = Dilysiad wedi'i anfon
+# LOCALIZATION NOTE (verificationSentBody) - %S = Email address of user's Firefox Account
+verificationSentBody = Mae dolen dilysu wedi'i anfon at %S.
+verificationNotSentTitle = Methu Anfon y Dilysiad
+verificationNotSentBody = Nid ydym yn gallu anfon e-bost dilysu ar hy o bryd, ceisiwch eto'n hwyrach.
+
+# LOCALIZATION NOTE (deviceConnDisconnTitle) - the title shown in a notification
+# when either this device or another device has connected to, or disconnected
+# from, a Firefox Account.
+deviceConnDisconnTitle = Cyfrif Firefox
+
+# LOCALIZATION NOTE (otherDeviceConnectedBody, otherDeviceConnectedBody.noDeviceName)
+# These strings are used in a notification shown when a new device joins the
+# Firefox account.
+# %S is the name of the new device; otherDeviceConnectedBody.noDeviceName is shown
+# instead of otherDeviceConnectedBody when the name is not known.
+otherDeviceConnectedBody = Mae'r cyfrifiadur hwn bellach wedi'i gysylltu i %S.
+otherDeviceConnectedBody.noDeviceName = Mae'r cyfrifiadur hwn bellach wedi'i gysylltu i ddyfais newydd.
+
+# LOCALIZATION NOTE (thisDeviceConnectedBody) - used in a notification shown
+# after a Firefox Account is connected to the current device.
+thisDeviceConnectedBody = Rydych wedi mewngofnodi'n llwyddiannus
+
+# LOCALIZATION NOTE (thisDeviceDisconnectedBody) - used in a notification shown
+# after the Firefox Account was disconnected remotely.
+thisDeviceDisconnectedBody = Mae'r cyfrifiadur hwn wedi'i ddatgysylltu.
+
+# LOCALIZATION NOTE (sendToAllDevices.menuitem)
+# Displayed in the Send Tab/Page/Link to Device context menu when right clicking a tab, a page or a link.
+sendToAllDevices.menuitem = Anfon i Bob Dyfais
+
+# LOCALIZATION NOTE (manageDevices.menuitem)
+# Displayed in the Send Tab/Page/Link to Device context menu when right clicking a tab, a page or a link.
+manageDevices.menuitem = Rheoli Dyfeisiadau…
+
+# LOCALIZATION NOTE (sendTabToDevice.unconfigured, sendTabToDevice.unconfigured.label2)
+# Displayed in the Send Tabs context menu when right clicking a tab, a page or a link
+# and the Sync account is unconfigured. Redirects to a marketing page.
+sendTabToDevice.unconfigured.label2 = Heb Fewngofnodi
+sendTabToDevice.unconfigured = Dysgu am Anfon Tabiau…
+
+# LOCALIZATION NOTE (sendTabToDevice.signintofxa)
+# Displayed in the Send Tabs context menu and the page action panel when FxA is not
+# configured. Allows users to immediately sign into FxA via the preferences.
+# %S is replaced by brandProductName.
+sendTabToDevice.signintofxa = Mewngofnodi i %S…
+
+# LOCALIZATION NOTE (sendTabToDevice.singledevice, sendTabToDevice.connectdevice,
+# sendTabToDevice.singledevice.status)
+# Displayed in the Send Tabs context menu when right clicking a tab, a page or a link
+# and the Sync account has only 1 device. The sendTabToDevice.singledevice link
+# redirects to a marketing page, the sendTabToDevice.connectdevice redirects
+# to an FxAccounts page that tells to you to connect another device.
+sendTabToDevice.singledevice.status = Dim Dyfais wedi ei Gysylltu
+sendTabToDevice.singledevice = Dysgu am Anfon Tabiau…
+sendTabToDevice.connectdevice = Cysylltu Dyfais Arall…
+
+# LOCALIZATION NOTE (sendTabToDevice.verify, sendTabToDevice.verify.status)
+# Displayed in the Send Tabs context menu when right clicking a tab, a page or a link
+# and the Sync account is unverified. Redirects to the Sync preferences page.
+sendTabToDevice.verify.status = Cyfrif Heb ei Wirio
+sendTabToDevice.verify = Gwiriwch eich Cyfrif…
+
+# LOCALIZATION NOTE (tabArrivingNotification.title, tabArrivingNotificationWithDevice.title,
+# multipleTabsArrivingNotification.title, unnamedTabsArrivingNotification2.body,
+# unnamedTabsArrivingNotificationMultiple2.body, unnamedTabsArrivingNotificationNoDevice.body,
+# singleTabArrivingWithTruncatedURL.body)
+# These strings are used in a notification shown when we're opening tab(s) another device sent us to display.
+
+# LOCALIZATION NOTE (tabArrivingNotification.title, tabArrivingNotificationWithDevice.title)
+# The body for these is the URL of the tab received
+tabArrivingNotification.title = Tab wedi'i Dderbyn
+# LOCALIZATION NOTE (tabArrivingNotificationWithDevice.title) %S is the device name
+tabArrivingNotificationWithDevice.title = Tab gan %S
+
+multipleTabsArrivingNotification.title = Tab wedi'i Dderbyn
+# LOCALIZATION NOTE (unnamedTabsArrivingNotification2.body):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs received and #2 is the device name.
+unnamedTabsArrivingNotification2.body = Nid oes tabiau wedi cyrraedd #2;Mae #1 tab wedi cyrraedd o #2;Mae #1 dab wedi cyrraedd o #2;Mae #1 thab wedi cyrraedd o #2;Mae #1 tab wedi cyrraedd o #2;Mae #1 tab wedi cyrraedd o #2
+# LOCALIZATION NOTE (unnamedTabsArrivingNotificationMultiple2.body):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs received.
+unnamedTabsArrivingNotificationMultiple2.body = Nid oes tabiau wedi cyrraedd o'ch ddyfeisiau cysylltiedig;Mae #1 tab wedi cyrraedd o'ch ddyfeisiau cysylltiedig;Mae #1 dab wedi cyrraedd o'ch ddyfeisiau cysylltiedig;Mae #1 thab wedi cyrraedd o'ch ddyfeisiau cysylltiedig;Mae #1 tab wedi cyrraedd o'ch ddyfeisiau cysylltiedig;Mae #1 tab wedi cyrraedd o'ch ddyfeisiau cysylltiedig
+
+# LOCALIZATION NOTE (unnamedTabsArrivingNotificationNoDevice.body):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs received
+# This version is used when we don't know any device names.
+unnamedTabsArrivingNotificationNoDevice.body = Nid oes tabiau wedi cyrraedd;Mae #1 tab wedi cyrraedd;Mae #1 dab wedi cyrraedd;Mae #1 thab wedi cyrraedd;Mae #1 tab wedi cyrraedd;Mae #1 tab wedi cyrraedd
+
+# LOCALIZATION NOTE (singleTabArrivingWithTruncatedURL.body):
+# Used when a tab from a remote device arrives but the URL must be truncated.
+# Should display the URL with an indication that it's benen truncated.
+# %S is the portion of the URL that remains after truncation.
+singleTabArrivingWithTruncatedURL.body = %S…
+
+# LOCALIZATION NOTE (account.title):
+# Used as a default header for the FxA toolbar menu.
+account.title = Cyfrif
+
+# LOCALIZATION NOTE (account.accountSettings):
+# Used as the description below user's email in the FxA toolbar menu.
+account.accountSettings = Gosodiadau'r Cyfrif
+
+# LOCALIZATION NOTE (account.finishAccountSetup):
+# Used as the FxA toolbar menu item value when user has not
+# finished setting up an account.
+account.finishAccountSetup = Gorffen Creu Cyfrif
+
+# LOCALIZATION NOTE (account.reconnectToFxA):
+# Used as the FxA toolbar menu item title when the user
+# needs to reconnect their account.
+account.reconnectToFxA = Ailgysylltu i Gyfrif Firefox
diff --git a/l10n-cy/browser/chrome/browser/app-extension-fields.properties b/l10n-cy/browser/chrome/browser/app-extension-fields.properties
new file mode 100644
index 0000000000..a7b99522e0
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/app-extension-fields.properties
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (extension.firefox-compact-light@mozilla.org.name): This is displayed in about:addons -> Appearance
+extension.firefox-compact-light@mozilla.org.name=Golau
+extension.firefox-compact-light@mozilla.org.description=Thema gyda chynllun lliw golau.
+
+# LOCALIZATION NOTE (extension.firefox-compact-dark@mozilla.org.name): This is displayed in about:addons -> Appearance
+extension.firefox-compact-dark@mozilla.org.name=Tywyll
+extension.firefox-compact-dark@mozilla.org.description=Thema sydd â chynllun lliw tywyll.
+
+# LOCALIZATION NOTE (extension.firefox-alpenglow@mozilla.org.name): This is displayed in about:addons -> Appearance
+extension.firefox-alpenglow@mozilla.org.name=Firefox Alpenglow
+extension.firefox-alpenglow@mozilla.org.description=Defnyddiwch wedd liwgar ar gyfer botymau, dewislenni, a ffenestri.
diff --git a/l10n-cy/browser/chrome/browser/baseMenuOverlay.dtd b/l10n-cy/browser/chrome/browser/baseMenuOverlay.dtd
new file mode 100644
index 0000000000..76f4946144
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/baseMenuOverlay.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY aboutProduct2.label      "Ynghylch &brandShorterName;">
+<!ENTITY aboutProduct2.accesskey  "n">
+
+<!ENTITY preferencesCmdMac.label        "Dewisiadau…">
+
+<!ENTITY servicesMenuMac.label          "Gwasanaethau">
+
+<!ENTITY hideThisAppCmdMac2.label       "Cuddio &brandShorterName;">
+
+<!ENTITY hideOtherAppsCmdMac.label      "Cuddio Eraill">
+
+<!ENTITY showAllAppsCmdMac.label        "Dangos Popeth">
+
+<!ENTITY touchBarCmdMac.label           "Cyfaddasu'r Bar Cyffwrdd…">
diff --git a/l10n-cy/browser/chrome/browser/brandings.dtd b/l10n-cy/browser/chrome/browser/brandings.dtd
new file mode 100644
index 0000000000..46a76ff0ff
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/brandings.dtd
@@ -0,0 +1,13 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE:
+	The following feature names must be treated as a brand, and kept in English.
+	They cannot be:
+	- Declined to adapt to grammatical case.
+	- Transliterated.
+	- Translated. -->
+
+<!ENTITY sendFullName "Firefox Send">
+<!ENTITY monitorFullName "Firefox Monitor">
diff --git a/l10n-cy/browser/chrome/browser/browser.dtd b/l10n-cy/browser/chrome/browser/browser.dtd
new file mode 100644
index 0000000000..7ef2249ec2
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/browser.dtd
@@ -0,0 +1,282 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE : FILE This file contains the browser main menu items -->
+<!-- LOCALIZATION NOTE : FILE Do not translate commandkeys -->
+
+<!ENTITY appmenu.tooltip                     "Agor y ddewislen">
+<!ENTITY navbarOverflow.label                "Rhagor o offer…">
+
+<!-- Tab context menu -->
+
+<!-- LOCALIZATION NOTE (pinTab.label, unpinTab.label): "Pin" is being
+used as a metaphor for expressing the fact that these tabs are "pinned" to the
+left edge of the tabstrip. Really we just want the string to express the idea
+that this is a lightweight and reversible action that keeps your tab where you
+can reach it easily. -->
+<!ENTITY  pinTab.label                       "Pinio Tab">
+<!ENTITY  unpinTab.label                     "Dadbinio Tab">
+
+<!ENTITY  listAllTabs.label      "Rhestru pob tab">
+
+<!ENTITY tabCmd.label "Tab Newydd">
+<!ENTITY openFileCmd.label "Agor Ffeil…">
+<!ENTITY printCmd.label "Argraffu…">
+
+<!ENTITY taskManagerCmd.label "Rheolwr Tasgau">
+
+<!ENTITY menubarCmd.label "Bar Dewislen">
+<!ENTITY menubarCmd.accesskey "B">
+<!-- LOCALIZATION NOTE: The accessibleLabel is a spoken label that should not
+include the word "toolbar" or such, because screen readers already know that
+this container is a toolbar. This avoids double-speaking. -->
+<!ENTITY navbar.accessibleLabel "Llywio">
+<!ENTITY personalbarCmd.label "Bar Offer Nodau Tudalen">
+<!ENTITY personalbarCmd.accesskey "N">
+<!-- LOCALIZATION NOTE: The accessibleLabel is a spoken label that should not
+include the word "toolbar" or such, because screen readers already know that
+this container is a toolbar. This avoids double-speaking. -->
+<!ENTITY personalbar.accessibleLabel "Nodau Tudalen">
+<!ENTITY bookmarksToolbarItem.label "Eitemau Bar Offer Nodau Tudalen">
+
+<!ENTITY fullScreenCmd.label "Sgrin Lawn">
+
+<!ENTITY pictureInPictureHideToggle.label "Cuddio'r Togl Llun mewn Llun">
+<!ENTITY pictureInPictureHideToggle.accesskey "L">
+
+<!-- LOCALIZATION NOTE (fxa.menu) Used to define the different labels
+     for the Firefox Account toolbar menu screen. The `Signed in as` text is
+     followed by the user's email. -->
+<!ENTITY fxa.menu.syncSettings2.label "Gosodiadau &syncBrand.shortName.label;">
+<!ENTITY fxa.menu.connectAnotherDevice2.label "Cysylltu Dyfais Arall…">
+<!ENTITY fxa.menu.firefoxAccount "&syncBrand.fxAccount.label;">
+<!ENTITY fxa.menu.signin.label "Mewngofnodi i &brandProductName;">
+<!ENTITY fxa.menu.turnOnSync.label "Troi &syncBrand.shortName.label; ymlaen">
+<!ENTITY fxa.menu.firefoxServices.label "Gwasanaethau &brandProductName;">
+<!ENTITY fxa.menu.account.label "Cyfrif">
+<!ENTITY fxa.menu.settings.label "Gosodiadau">
+<!ENTITY fxa.menu.accountSettings.label "Gosodiadau Cyfrif">
+<!ENTITY fxa.menu.manageAccount2.label "Rheoli Cyfrif">
+<!ENTITY fxa.menu.signOut.label "Allgofnodi…">
+<!ENTITY fxa.menu.setupSync.label "Gosod &syncBrand.shortName.label;…">
+
+<!-- LOCALIZATION NOTE (fxa.service) Used to define the different FxA services
+     for the Firefox Account toolbar menu screen.  -->
+<!ENTITY fxa.service.sendTab.description "Anfon tab ar unwaith i unrhyw ddyfais rydych wedi mewngofnodi arni.">
+
+<!-- LOCALIZATION NOTE (fullscreenWarning.beforeDomain.label,
+     fullscreenWarning.afterDomain.label): these two strings are used
+     respectively before and after the domain requiring fullscreen.
+     Localizers can use one of them, or both, to better adapt this
+     sentence to their language. -->
+<!ENTITY fullscreenWarning.beforeDomain.label "">
+<!ENTITY fullscreenWarning.afterDomain.label "nawr yn sgrin lawn">
+<!ENTITY fullscreenWarning.generic.label "Mae'r ddogfen nawr yn sgrin lawn">
+
+<!-- LOCALIZATION NOTE (exitDOMFullscreen.button,
+     exitDOMFullscreenMac.button): the "escape" button on PC keyboards
+     is uppercase, while on Mac keyboards it is lowercase -->
+<!ENTITY exitDOMFullscreen.button "Gadael y Sgrin Lawn (Esc)">
+<!ENTITY exitDOMFullscreenMac.button "Gadael y Sgrin Lawn (esc)">
+
+<!-- LOCALIZATION NOTE (pointerlockWarning.beforeDomain.label,
+     pointerlockWarning.afterDomain.label): these two strings are used
+     respectively before and after the domain requiring pointerlock.
+     Localizers can use one of them, or both, to better adapt this
+     sentence to their language. -->
+<!ENTITY pointerlockWarning.beforeDomain.label "">
+<!ENTITY pointerlockWarning.afterDomain.label "reolaeth o'ch pwyntydd. Pwyswch Esc i adennill rheolaeth.">
+<!ENTITY pointerlockWarning.generic.label "Mae gan y ddogfen hon reolaeth o'ch pwyntydd. Pwyswch Esc i adennill rheolaeth.">
+
+<!ENTITY showAllBookmarks2.label "Dangos Pob Nod Tudalen">
+<!ENTITY recentBookmarks.label "Wedi gosod Nod Tudalen yn Ddiweddar">
+<!ENTITY bookmarksToolbarChevron.tooltip "Dangos pob ffolder nod tudalen">
+
+<!ENTITY printButton.label            "Argraffu">
+<!ENTITY printButton.tooltip          "Argraffu'r dudalen">
+
+<!ENTITY searchItem.title             "Chwilio">
+
+<!-- Toolbar items -->
+<!ENTITY homeButton.label             "Cartref">
+<!ENTITY homeButton.defaultPage.tooltip "Cartref &brandShortName;">
+
+<!ENTITY bookmarksButton.label          "Nodau Tudalen">
+
+<!ENTITY bookmarksSubview.label             "Nodau Tudalen">
+<!ENTITY bookmarksMenuButton2.label         "Dewislen Nodau Tudalen">
+<!ENTITY bookmarksMenuButton.other.label    "Nodau Tudalen Eraill">
+<!ENTITY bookmarksMenuButton.mobile.label   "Nodau Tudalen Symudol">
+<!ENTITY viewBookmarksSidebar2.label        "Gweld Bar Offer Nodau Tudalen">
+<!ENTITY hideBookmarksSidebar.label         "Cuddio'r Bar Ochr Nodau Tudalen">
+<!ENTITY viewBookmarksToolbar.label         "Gweld Bar Offer Nodau Tudalen">
+<!ENTITY hideBookmarksToolbar.label         "Cuddio'r Bar Offer Nodau Tudalen">
+<!ENTITY searchBookmarks.label              "Chwilio'r Nodau Tudalen">
+<!ENTITY bookmarkingTools.label             "Offer Nodau Tudalen">
+<!ENTITY addBookmarksMenu.label             "Ychwanegu Dewislen Nodau Tudalen i'r Bar Offer">
+<!ENTITY removeBookmarksMenu.label          "Tynnu Dewislen Nodau Tudalen o'r Bar Offer">
+
+<!ENTITY historyButton.label            "Hanes">
+
+<!ENTITY downloads.label              "Llwytho i Lawr">
+<!-- LOCALIZATION NOTE (libraryDownloads.label): This label is similar to
+  -  downloads.label, but used in the Library panel. -->
+<!ENTITY libraryDownloads.label       "Llwythi">
+<!ENTITY addons.label                 "Ychwanegion">
+
+<!ENTITY webDeveloperMenu.label       "Datblygwr Gwe">
+
+<!ENTITY newNavigatorCmd.label        "Ffenestr Newydd">
+<!ENTITY newPrivateWindow.label     "Ffenestr Breifat Newydd">
+
+<!ENTITY editMenu.label         "Golygu">
+<!ENTITY preferencesCmd2.label       "Opsiynau">
+<!ENTITY preferencesCmdUnix.label       "Dewisiadau">
+<!ENTITY logins.label                           "Mewngofnodion a Chyfrineiriau">
+
+<!ENTITY overflowCustomizeToolbar.label       "Cyfaddasu'r Bar Offer…">
+<!ENTITY overflowCustomizeToolbar.accesskey   "C">
+
+<!ENTITY historyMenu.label "Hanes">
+<!ENTITY historyUndoMenu.label "Tabiau Wedi eu Cau'n Ddiweddar">
+<!-- LOCALIZATION NOTE (historyUndoWindowMenu): see bug 394759 -->
+<!ENTITY historyUndoWindowMenu.label "Ffenestri wedi eu Cau yn Ddiweddar">
+
+<!ENTITY appMenuHistory.showAll.label "Dangos yr Holl Hanes">
+<!ENTITY appMenuHistory.clearRecent.label "Clirio Hanes Diweddar…">
+<!ENTITY appMenuHistory.restoreSession.label "Adfer y Sesiwn Flaenorol">
+<!ENTITY appMenuHistory.viewSidebar.label "Gweld Bar Ochr Hanes">
+<!ENTITY appMenuHistory.hideSidebar.label "Cuddio'r Bar Ochr Hanes">
+<!ENTITY appMenuHistory.recentHistory.label "Hanes Diweddar">
+<!ENTITY appMenuHelp.label "Cymorth">
+
+<!ENTITY appMenuRemoteTabs.label "Tabiau wedi'u Cydweddu">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.notabs.label): This is shown beneath
+     the name of a device when that device has no open tabs -->
+<!ENTITY appMenuRemoteTabs.notabs.label "Dim tabiau agored">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.showMore.label, appMenuRemoteTabs.showMore.tooltip):
+     This is shown after the tabs list if we can display more tabs by clicking on the button -->
+<!ENTITY appMenuRemoteTabs.showMore.label "Dangos Rhagor">
+<!ENTITY appMenuRemoteTabs.showMore.tooltip "Dangos rhagor o dabiau o'r ddyfais hon">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.showAll.label, appMenuRemoteTabs.showAll.tooltip):
+     This is shown after the tabs list if we can all the remaining tabs by clicking on the button -->
+<!ENTITY appMenuRemoteTabs.showAll.label "Dangos Popeth">
+<!ENTITY appMenuRemoteTabs.showAll.tooltip "Dangos pob tab o'r ddyfais hon">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.tabsnotsyncing.label): This is shown
+     when Sync is configured but syncing tabs is disabled. -->
+<!ENTITY appMenuRemoteTabs.tabsnotsyncing.label "Cychwynnwch gydweddu tabiau er mwyn gweld rhestr o dabiau o'ch dyfeisiau eraill.">
+<!-- LOCALIZATION NOTE (appMenuRemoteTabs.noclients.subtitle): This is shown
+     when Sync is configured but this appears to be the only device attached to
+     the account. We also show links to download Firefox for android/ios. -->
+<!ENTITY appMenuRemoteTabs.noclients.subtitle "Hoffech chi weld eich tabiau o ddyfeisiau eraill yma?">
+<!ENTITY appMenuRemoteTabs.opensyncprefs.label "Agor Dewisiadau Sync">
+<!ENTITY appMenuRemoteTabs.welcome.label "Gweld rhestr o dabiau o'ch dyfeisiau eraill.">
+<!ENTITY appMenuRemoteTabs.unverified.label "Mae angen i'ch cyfrif cael ei gwirio.">
+<!ENTITY appMenuRemoteTabs.signintosync.label "Mewngofnodi i &syncBrand.shortName.label;…">
+<!ENTITY appMenuRemoteTabs.turnonsync.label "Cychwyn &syncBrand.shortName.label;…">
+<!ENTITY appMenuRemoteTabs.managedevices.label "Rheoli Dyfeisiadau…">
+<!ENTITY appMenuRemoteTabs.sidebar.label "Gweld Bar Ochr Tabiau wedi eu Cydweddu">
+<!ENTITY appMenuRemoteTabs.hidesidebar.label "Cuddio'r Bar Ochr Cydweddwyd">
+<!ENTITY appMenuRemoteTabs.connectdevice.label "Cysylltu Dyfais Arall">
+
+<!ENTITY appMenuRecentHighlights.label "Uchafbwyntiau Diweddar">
+
+<!ENTITY customizeMenu.addToToolbar.label "Ychwanegu i'r Bar Offer">
+<!ENTITY customizeMenu.addToToolbar.accesskey "Y">
+<!-- LOCALIZATION NOTE (customizeMenu.addToOverflowMenu.label,
+     customizeMenu.unpinFromOverflowMenu.label)
+     The overflow menu is the menu that appears if you click the chevron (>> button)
+     in the location bar. -->
+<!ENTITY customizeMenu.addToOverflowMenu.label "Ychwanegu at y Ddewislen Ychwanegol">
+<!ENTITY customizeMenu.addToOverflowMenu.accesskey "D">
+<!ENTITY customizeMenu.unpinFromOverflowMenu.label "Dadbinio o'r Ddewislen Ychwanegol">
+<!ENTITY customizeMenu.unpinFromOverflowMenu.accesskey "D">
+<!ENTITY customizeMenu.removeFromToolbar.label "Tynnu o'r Bar Offer">
+<!ENTITY customizeMenu.removeFromToolbar.accesskey "T">
+<!ENTITY customizeMenu.addMoreItems.label "Ychwanegu Rhagor o Eitemau…">
+<!ENTITY customizeMenu.addMoreItems.accesskey "Y">
+
+<!-- LOCALIZATION NOTE (moreMenu.label) This label is used in the new Photon
+    app (hamburger) menu. When clicked, it opens a subview that contains
+    secondary commands. -->
+<!ENTITY moreMenu.label "Rhagor">
+
+<!ENTITY contentSearchSubmit.tooltip  "Cyflwyno'r chwilio">
+
+<!-- LOCALIZATION NOTE (searchInput.placeholder):
+     This string is displayed in the search box when the input field is empty. -->
+<!ENTITY searchInput.placeholder      "Chwilio">
+<!ENTITY searchIcon.tooltip           "Chwilio">
+
+<!ENTITY openLinkCmdInTab.accesskey   "T">
+
+<!ENTITY pageAction.copyLink.label    "Copïo'r Ddolen">
+
+<!-- LOCALIZATION NOTE(pocket-button.tooltiptext, saveToPocketCmd.label, saveLinkToPocketCmd.label, pocketMenuitem.label):
+  "Pocket" is a brand name. -->
+<!ENTITY saveToPocketCmd.label        "Cadw Tudalen i Pocket">
+
+<!-- LOCALIZATION NOTE(pocket-button.tooltiptext, saveToPocketCmd.label, saveLinkToPocketCmd.label, pocketMenuitem.label):
+  "Pocket" is a brand name. -->
+<!ENTITY pocketMenuitem.label         "Edrych ar Rhestr Pocket">
+
+<!ENTITY emailPageCmd.label           "E-bostio'r Ddolen…">
+
+<!ENTITY fullZoom.label                 "Chwyddo">
+
+<!ENTITY sidebarCloseButton.tooltip     "Cau'r bar ochr">
+
+<!ENTITY quitApplicationCmdWin2.label       "Gadael">
+<!ENTITY quitApplicationCmdWin2.accesskey   "G">
+<!ENTITY quitApplicationCmdWin2.tooltip     "Gadael &brandShorterName;">
+<!ENTITY quitApplicationCmd.label       "Gadael">
+<!ENTITY quitApplicationCmd.accesskey   "G">
+<!ENTITY quitApplicationCmdMac2.label   "Gadael &brandShorterName;">
+
+<!ENTITY allowPopups.accesskey "l">
+<!-- On Windows we use the term "Options" to describe settings, but
+     on Linux and Mac OS X we use "Preferences" - carry that distinction
+     over into this string, which is used in the "popup blocked" info bar . -->
+<!ENTITY editPopupSettingsUnix.label "Golygu Dewisiadau Rhwystro Llamlenni…">
+<!ENTITY editPopupSettings.label "Golygu Opsiynau Rhwystro Llamlenni…">
+<!ENTITY editPopupSettings.accesskey "e">
+<!ENTITY dontShowMessage.accesskey "P">
+
+<!ENTITY findOnCmd.label     "Canfod ar y Dudalen…">
+
+<!ENTITY spellAddDictionaries.label "Ychwanegu Geiriaduron…">
+<!ENTITY spellAddDictionaries.accesskey "G">
+
+<!-- Name for the tabs toolbar as spoken by screen readers.
+     The word "toolbar" is appended automatically and should not be contained below! -->
+<!ENTITY tabsToolbar.label "Tabiau porwyr">
+
+<!ENTITY syncBrand.shortName.label    "Sync">
+
+<!ENTITY customizeMode.autoHideDownloadsButton.label "Awto-guddio">
+
+
+<!ENTITY uiTour.infoPanel.close "Cau">
+
+<!ENTITY panicButton.thankyou.msg1                "Mae eich hanes diweddar wedi ei glirio.">
+<!ENTITY panicButton.thankyou.msg2                "Pori diogel!">
+<!ENTITY panicButton.thankyou.buttonlabel         "Diolch!">
+
+<!ENTITY updateAvailable.panelUI.label "Llwytho diweddariad &brandShorterName; i lawr">
+<!ENTITY updateManual.panelUI.label "Llwytho i lawr fersiwn newydd o &brandShorterName;">
+<!ENTITY updateUnsupported.panelUI.label "Nid oes modd i chi gyflawni diweddariadau pellach">
+<!ENTITY updateRestart.panelUI.label2 "Ailgychwyn i ddiweddaru &brandShorterName;">
+
+<!ENTITY sendToDevice.syncNotReady.label "Cydweddu Dyfeisiau…">
+
+<!ENTITY pageAction.shareUrl.label "Rhannu">
+<!ENTITY pageAction.shareMore.label "Rhagor…">
+
+<!ENTITY libraryButton.tooltip "Gweld hanes, nodau tudalen wedi eu cadw, a rhagor">
+
+<!-- LOCALIZATION NOTE: (accessibilityIndicator.tooltip): This is used to
+     display a tooltip for accessibility indicator in toolbar/tabbar. It is also
+     used as a textual label for the indicator used by assistive technology
+     users. -->
+<!ENTITY accessibilityIndicator.tooltip "Nodweddion Hygyrchedd wedi eu Galluogi">
diff --git a/l10n-cy/browser/chrome/browser/browser.properties b/l10n-cy/browser/chrome/browser/browser.properties
new file mode 100644
index 0000000000..0221653585
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/browser.properties
@@ -0,0 +1,1064 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+nv_timeout=Daeth yr amser i ben
+openFile=Agor Ffeil
+
+droponhometitle=Gosod Tudalen Cartref
+droponhomemsg=Ydych chi am i'r ddogfen fod yn dudalen cartref newydd i chi?
+droponhomemsgMultiple=Hoffech chi i'r dogfennau hyn fod yn dudalennau cartref newydd i chi?
+
+# context menu strings
+
+# LOCALIZATION NOTE (contextMenuSearch): %1$S is the search engine,
+# %2$S is the selection string.
+contextMenuSearch=Chwilio %1$S am "%2$S"
+contextMenuSearch.accesskey=C
+contextMenuPrivateSearch=Chwilio mewn Ffenestr Breifat
+contextMenuPrivateSearch.accesskey=h
+# LOCALIZATION NOTE (contextMenuPrivateSearchOtherEngine): %S is the search
+# engine name as set for Private Browsing mode. This label is only used when
+# this engine is different from the default engine name used in normal mode.
+contextMenuPrivateSearchOtherEngine=Chwilio gyda %S mewn Ffenestr Breifat
+contextMenuPrivateSearchOtherEngine.accesskey=h
+
+# bookmark dialog strings
+
+bookmarkAllTabsDefault=[Enw Ffolder]
+
+xpinstallPromptMessage=Rhwystrodd %S y wefan rhag gofyn i chi osod meddalwedd ar eich cyfrifiadur.
+# LOCALIZATION NOTE (xpinstallPromptMessage.header)
+# The string contains the hostname of the site the add-on is being installed from.
+xpinstallPromptMessage.header=Caniatáu i %S osod ategyn?
+xpinstallPromptMessage.message=Rydych yn ceisio gosod ychwanegyn o %S. Gwnewch yn siŵr eich bod yn ymddiried yn y wefan hon cyn parhau.
+xpinstallPromptMessage.header.unknown=Caniatáu i wefan anhysbys osod ategyn?
+xpinstallPromptMessage.message.unknown=Rydych yn ceisio gosod ychwanegyn o wefan anhysbys. Gwnewch yn siŵr eich bod yn ymddiried yn y wefan hon cyn parhau.
+xpinstallPromptMessage.learnMore=Dysgwch ragor am osod ategion yn ddiogel
+xpinstallPromptMessage.dontAllow=Peidio Caniatáu
+xpinstallPromptMessage.dontAllow.accesskey=P
+xpinstallPromptMessage.neverAllow=Byth Caniatáu
+xpinstallPromptMessage.neverAllow.accesskey=B
+# Accessibility Note:
+# Be sure you do not choose an accesskey that is used elsewhere in the active context (e.g. main menu bar, submenu of the warning popup button)
+# See https://website-archive.mozilla.org/www.mozilla.org/access/access/keyboard/ for details
+xpinstallPromptMessage.install=Ymlaen i'r Gosod
+xpinstallPromptMessage.install.accesskey=G
+
+xpinstallDisabledMessageLocked=Mae gosod meddalwedd wedi ei analluogi gan eich gweinyddwr system.
+xpinstallDisabledMessage=Mae gosod meddalwedd wedi ei analluogi. Cliciwch Galluogi a cheisio eto.
+xpinstallDisabledButton=Galluogi
+xpinstallDisabledButton.accesskey=a
+
+# LOCALIZATION NOTE (addonInstallBlockedByPolicy)
+# This message is shown when the installation of an add-on is blocked by
+# enterprise policy. %1$S is replaced by the name of the add-on.
+# %2$S is replaced by the ID of add-on. %3$S is a custom message that
+# the administration can add to the message.
+addonInstallBlockedByPolicy=Mae %1$S (%2$S) wedi ei analluogi gan eich gweinyddwr system.%3$S
+addonInstallFullScreenBlocked=Nid yw gosod ychwanegiad yn cael ei ganiatáu wrth fynd i'r modd sgrin lawn neu cyn hynny.
+
+# LOCALIZATION NOTE (webextPerms.header)
+# This string is used as a header in the webextension permissions dialog,
+# %S is replaced with the localized name of the extension being installed.
+# See https://bug1308309.bmoattachments.org/attachment.cgi?id=8814612
+# for an example of the full dialog.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.header=Ychwanegu %S?
+
+webextPerms.unsignedWarning=Rhybudd: Nid yw'r ychwanegyn hwn wedi ei wirio. Gall ychwanegion maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Gosodwch hwn dim ond os ydych yn ymddiried yn ei ffynhonnell.
+
+# LOCALIZATION NOTE (webextPerms.listIntro)
+# This string will be followed by a list of permissions requested
+# by the webextension.
+webextPerms.listIntro=Mae'n gofyn am eich caniatâd i:
+webextPerms.learnMore=Dysgu rhagor am ganiatâd
+webextPerms.add.label=Ychwanegu
+webextPerms.add.accessKey=Y
+webextPerms.cancel.label=Diddymu
+webextPerms.cancel.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.sideloadMenuItem)
+# %1$S will be replaced with the localized name of the sideloaded add-on.
+# %2$S will be replace with the name of the application (e.g., Firefox, Nightly)
+webextPerms.sideloadMenuItem=Mae %1$S wedi ei ychwanegu at %2$S
+
+# LOCALIZATION NOTE (webextPerms.sideloadHeader)
+# This string is used as a header in the webextension permissions dialog
+# when the extension is side-loaded.
+# %S is replaced with the localized name of the extension being installed.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.sideloadHeader=Mae %S wedi ei ychwanegu
+webextPerms.sideloadText2=Mae rhaglen arall ar eich cyfrifiadur wedi gosod ychwanegyn y gall effeithio ar eich porwr. Darllenwch geisiadau caniatâd yr ychwanegyn a dewis i Alluogi neu Ddiddymu (ei adael wedi ei analluogi).
+webextPerms.sideloadTextNoPerms=Mae rhaglen arall ar eich cyfrifiadur wedi gosod ychwanegyn y gall effeithio ar eich porwr. Darllenwch geisiadau caniatâd yr ychwanegyn a dewis i Alluogi neu Ddiddymu (i'w adael wedi ei analluogi).
+
+webextPerms.sideloadEnable.label=Galluogi
+webextPerms.sideloadEnable.accessKey=G
+webextPerms.sideloadCancel.label=Diddymu
+webextPerms.sideloadCancel.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.updateMenuItem)
+# %S will be replaced with the localized name of the extension which
+# has been updated.
+webextPerms.updateMenuItem=Mae %S angen caniatâd newydd
+
+# LOCALIZATION NOTE (webextPerms.updateText)
+# %S is replaced with the localized name of the updated extension.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.updateText=Mae %S wedi ei ddiweddaru. Rhaid cymeradwyo'r caniatâd newydd cyn i'r fersiwn mwy diweddar gael ei osod. Bydd dewis “Diddymu” yn cadw eich ychwanegyn cyfredol.
+
+webextPerms.updateAccept.label=Diweddaru
+webextPerms.updateAccept.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.optionalPermsHeader)
+# %S is replace with the localized name of the extension requested new
+# permissions.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.optionalPermsHeader=Mae %S yn gofyn am ganiatâd ychwanegol.
+webextPerms.optionalPermsListIntro=Mae eisiau:
+webextPerms.optionalPermsAllow.label=Caniatáu
+webextPerms.optionalPermsAllow.accessKey=C
+webextPerms.optionalPermsDeny.label=Gwrthod
+webextPerms.optionalPermsDeny.accessKey=G
+
+webextPerms.description.bookmarks=Darllen a newid nodau tudalen
+webextPerms.description.browserSettings=Darllen a newid gosodiadau'r porwr
+webextPerms.description.browsingData=Clirio'r hanes pori diweddar, cwcis a data cysylltiedig
+webextPerms.description.clipboardRead=Estyn data o'r clipfwrdd
+webextPerms.description.clipboardWrite=Mewnbynnu data i'r clipfwrdd
+webextPerms.description.devtools=Estyn offer datblygwyr i gael mynediad at eich data mewn tabiau agored
+webextPerms.description.downloads=Llwytho i lawr, darllen ffeiliau a newid hanes llwytho i lawr y porwr
+webextPerms.description.downloads.open=Agor ffeiliau a llwythwyd i lawr i'ch cyfrifiadur
+webextPerms.description.find=Darllen testun yr holl dabiau sydd ar agor
+webextPerms.description.geolocation=Mynediad i'ch lleoliad
+webextPerms.description.history=Mynediad at eich hanes pori
+webextPerms.description.management=Monitro'r defnydd o estyniadau a rheoli themâu
+# LOCALIZATION NOTE (webextPerms.description.nativeMessaging)
+# %S will be replaced with the name of the application
+webextPerms.description.nativeMessaging=Cyfnewid negeseuon gyda rhaglenni ar wahân i %S
+webextPerms.description.notifications=Dangos hysbysiadau i chi
+webextPerms.description.pkcs11=Darparu gwasanaethau dilysiad cryptograffig
+webextPerms.description.privacy=Darllen a newid gosodiadau preifatrwydd
+webextPerms.description.proxy=Rheoli gosodiadau dirprwy'r porwr
+webextPerms.description.sessions=Mynediad at y tabiau caewyd yn ddiweddar
+webextPerms.description.tabs=Mynediad at dabiau'r porwyr
+webextPerms.description.tabHide=Cuddio a dangos tabiau'r porwr
+webextPerms.description.topSites=Mynediad at eich hanes pori
+webextPerms.description.webNavigation=Cael mynediad at weithgaredd wrth lywio
+
+webextPerms.hostDescription.allUrls=Cael mynediad i'ch data ar gyfer pob gwefan
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.wildcard)
+# %S will be replaced by the DNS domain for which a webextension
+# is requesting access (e.g., mozilla.org)
+webextPerms.hostDescription.wildcard=Cael mynediad i'ch data ym mhob gwefan ym mharth %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManyWildcards):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# domains for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManyWildcards=Peidio cael mynediad i'ch data mewn parthau eraill;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 barth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.oneSite)
+# %S will be replaced by the DNS host name for which a webextension
+# is requesting access (e.g., www.mozilla.org)
+webextPerms.hostDescription.oneSite=Cael mynediad at eich data yn %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManySites)
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# hosts for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManySites=Peidio cael mynediad i'ch data mewn gwefannau eraill;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 wefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall
+
+# LOCALIZATION NOTE (webext.defaultSearch.description)
+# %1$S is replaced with the localized named of the extension that is asking to change the default search engine.
+# %2$S is replaced with the name of the current search engine
+# %3$S is replaced with the name of the new search engine
+webext.defaultSearch.description=Mae %1$S eisiau newid eich peiriant chwilio rhagosodedig o %2$S i %3$S. Ydy hynny'n iawn?
+webext.defaultSearchYes.label=Iawn
+webext.defaultSearchYes.accessKey=I
+webext.defaultSearchNo.label=Na
+webext.defaultSearchNo.accessKey=N
+
+# LOCALIZATION NOTE (webext.remove.confirmation.title)
+# %S is the name of the extension which is about to be removed.
+webext.remove.confirmation.title=Tynnu %S
+# LOCALIZATION NOTE (webext.remove.confirmation.message)
+# %1$S is the name of the extension which is about to be removed.
+# %2$S is brandShorterName
+webext.remove.confirmation.message=Tynnu %1$S o %2$S?
+webext.remove.confirmation.button=Tynnu
+# LOCALIZATION NOTE (webext.remove.abuseReportCheckbox.message)
+# %S is vendorShortName
+webext.remove.abuseReportCheckbox.message=Rwyf am adrodd ar yr estyniad hwn i %S
+
+# LOCALIZATION NOTE (addonPostInstall.message1)
+# %1$S is replaced with the localized named of the extension that was
+# just installed.
+# %2$S is replaced with the localized name of the application.
+addonPostInstall.message1=Mae %1$S wedi ei ychwanegu at %2$S.
+
+# LOCALIZATION NOTE (addonDownloadingAndVerifying):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Also see https://bugzilla.mozilla.org/show_bug.cgi?id=570012 for mockups
+addonDownloadingAndVerifying=Llwytho i lawr a dilysu #1 ychwanegion…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…
+addonDownloadVerifying=Dilysu
+
+addonInstall.unsigned=(Heb eu gwirio)
+addonInstall.cancelButton.label=Diddymu
+addonInstall.cancelButton.accesskey=D
+addonInstall.acceptButton2.label=Ychwanegu
+addonInstall.acceptButton2.accesskey=Y
+
+# LOCALIZATION NOTE (addonConfirmInstallMessage,addonConfirmInstallUnsigned):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName
+# #2 is the number of add-ons being installed
+addonConfirmInstall.message=Hoffai'r wefan hon osod ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:
+addonConfirmInstallUnsigned.message=Rhybudd: Hoffai'r wefan hon osod ychwanegyn heb ei wirio yn #1. Mentrwch ar eich risg eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn heb eu gwirio yn #1. Mentrwch ar eich risg eich hun.
+
+# LOCALIZATION NOTE (addonConfirmInstallSomeUnsigned.message):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName
+# #2 is the total number of add-ons being installed (at least 2)
+addonConfirmInstallSomeUnsigned.message=Rhybudd: Hoffai'r wefan hon osod #2 ychwanegion yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.
+
+# LOCALIZATION NOTE (addonInstalled):
+# %S is the name of the add-on
+addonInstalled=Mae %S wedi'i osod yn llwyddiannus.
+# LOCALIZATION NOTE (addonsGenericInstalled):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of add-ons
+addonsGenericInstalled=Nid oes ychwanegion wedi eu gosod.;Mae #1 ychwanegyn wedi ei osod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.
+
+# LOCALIZATION NOTE (addonInstallError-1, addonInstallError-2, addonInstallError-3, addonInstallError-4, addonInstallError-5, addonLocalInstallError-1, addonLocalInstallError-2, addonLocalInstallError-3, addonLocalInstallError-4, addonLocalInstallError-5):
+# %1$S is the application name, %2$S is the add-on name
+addonInstallError-1=Nid oedd modd llwytho'r ychwanegyn i lawr oherwydd methiant y cysylltiad.
+addonInstallError-2=Nid oedd modd gosod yr ychwanegyn am nad yw'n cydweddu â'r ychwanegyn roedd %1$S yn ei ddisgwyl.
+addonInstallError-3=Nid oedd modd llwytho'r ychwanegyn i lawr o'r wefan hon oherwydd ei fod yn ymddangos yn llwgr.
+addonInstallError-4=Nid oedd modd gosod %2$S gan nad oedd %1$S yn gallu newid y linell angenrheidiol.
+addonInstallError-5=Mae %1$S wedi atal y wefan rhag gosod ychwanegyn sydd heb ei wirio.
+addonLocalInstallError-1=Nid oedd modd gosod yr ychwanegyn oherwydd gwall system.
+addonLocalInstallError-2=Nid oedd modd gosod yr ychwanegyn am nad yw'n cydweddu â'r ychwanegyn %1$S disgwyliwyd.
+addonLocalInstallError-3=Nid oedd modd gosod yr ychwanegyn am ei fod yn edrych yn llwgr.
+addonLocalInstallError-4=Nid oedd modd gosod %2$S gan nad oedd %1$S yn gallu newid y linell angenrheidiol.
+addonLocalInstallError-5=Nid oedd modd gosod yr ychwanegyn am nad yw wedi ei wirio.
+
+# LOCALIZATION NOTE (addonInstallErrorIncompatible):
+# %1$S is the application name, %2$S is the application version, %3$S is the add-on name
+addonInstallErrorIncompatible=Nid oedd modd gosod %3$S am nad yw'n cydweddu â %1$S %2$S.
+
+# LOCALIZATION NOTE (addonInstallErrorBlocklisted): %S is add-on name
+addonInstallErrorBlocklisted=Nid oedd modd gosod %S am fod risg uchel iddo achosi problemau sefydlogrwydd a diogelwch.
+
+unsignedAddonsDisabled.message=Mae un neu fwy o ychwanegion nad oedd modd eu gwirio wedi eu hanalluogi.
+unsignedAddonsDisabled.learnMore.label=Dysgu Rhagor
+unsignedAddonsDisabled.learnMore.accesskey=D
+
+# LOCALIZATION NOTE (popupWarning.message): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName and #2 is the number of pop-ups blocked.
+popupWarning.message=Nid yw gwefan #1 wedi rhwystro rhag agor llamlenni.;Rhwystrodd #1 y wefan rhag agor #2 llamlen.;Rhwystrodd #1 y wefan rhag agor #2 llamlen.;Rhwystrodd #1 y wefan rhag agor #2 llamlen.;Rhwystrodd #1 y wefan rhag agor #2 llamlen.;Rhwystrodd #1 y wefan rhag agor #2 llamlen.
+# LOCALIZATION NOTE (popupWarning.exceeded.message): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The singular form is left empty for English, since the number of blocked pop-ups is always greater than 1.
+# #1 is brandShortName and #2 is the number of pop-ups blocked.
+popupWarning.exceeded.message=;Rhwystrodd #1 y wefan hon rhag agor mwy na #2 llamlen.;Rhwystrodd #1 y wefan hon rhag agor mwy na #2 llamlen.;Rhwystrodd #1 y wefan hon rhag agor mwy na #2 llamlen.;Rhwystrodd #1 y wefan hon rhag agor mwy na #2 llamlen.;Rhwystrodd #1 y wefan hon rhag agor mwy na #2 llamlen.
+popupWarningButton=Opsiynau
+popupWarningButton.accesskey=D
+popupWarningButtonUnix=Dewisiadau
+popupWarningButtonUnix.accesskey=D
+popupAllow=Caniatáu llamlenni ar gyfer %S
+popupBlock=Rhwystro llamlenni ar gyfer %S
+popupWarningDontShowFromMessage=Peidio dangos y neges pan mae llamlenni wedi eu rhwystro
+popupShowPopupPrefix=Dangos '%S'
+
+# LOCALIZATION NOTE (popupShowBlockedPopupsIndicatorText): Semicolon separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of pop-ups blocked.
+popupShowBlockedPopupsIndicatorText=Nid oes llamlenni wedi eu rhwystro…;Dangos #1 llamlen wedi ei rwystro…;Dangos #1 llamlen wedi eu rhwystro…;Dangos #1 llamlen wedi eu rhwystro…;Dangos #1 llamlen wedi eu rhwystro…;Dangos #1 llamlen wedi eu rhwystro…
+
+# LOCALIZATION NOTE (geolocationLastAccessIndicatorText): %S is the relative time of the most recent geolocation access (e.g. 5 min. ago)
+geolocationLastAccessIndicatorText=Mynediad diwethaf %S
+
+# LOCALIZATION NOTE (openProtocolHandlerPermissionEntryLabel): %S is the scheme of the protocol the site may open an application for. For example: mailto
+openProtocolHandlerPermissionEntryLabel=Dolenni %S://
+
+crashedpluginsMessage.title=Mae'r ategyn %S wedi chwalu.
+crashedpluginsMessage.reloadButton.label=Ail lwytho tudalen
+crashedpluginsMessage.reloadButton.accesskey=A
+crashedpluginsMessage.submitButton.label=Cyflwyno adroddiad chwalu
+crashedpluginsMessage.submitButton.accesskey=C
+crashedpluginsMessage.learnMore=Dysgu Rhagor…
+
+# Keyword fixup messages
+# LOCALIZATION NOTE (keywordURIFixup.message): Used when the user tries to visit
+# a local host page, by the time the DNS request recognizes it, we have already
+# loaded a search page for the given word.  An infobar then asks to the user
+# whether he rather wanted to visit the host.  %S is the recognized host.
+keywordURIFixup.message=Oeddech chi'n bwriadu mynd i %S?
+keywordURIFixup.goTo=Oeddwn, cymrwch fi i %S
+keywordURIFixup.goTo.accesskey=O
+keywordURIFixup.dismiss=Dim diolch
+keywordURIFixup.dismiss.accesskey=D
+
+pluginInfo.unknownPlugin=Anhysbys
+
+# Flash activation doorhanger UI
+flashActivate.message=Hoffech chi adael i Adobe Flash redeg ar y wefan hon? Caniatewch Adobe Flash i redeg ar wefannau rydych yn ymddiried ynddyn nhw.
+flashActivate.outdated.message=Ydych chi eisiau rhedeg hen fersiwn o Adobe Flash ar y wefan hon? Gall hen fersiwn effeithio ar berfformiad a diogelwch eich porwr.
+flashActivate.noAllow=Peidio Caniatáu
+flashActivate.allow=Caniatáu
+flashActivate.noAllow.accesskey=P
+flashActivate.allow.accesskey=C
+
+# in-page UI
+# LOCALIZATION NOTE (PluginClickToActivate2): Two changes were done to the
+# previous version of the string. The first is that we changed the wording from
+# "Activate" to "Run", because it's shorter and feels less technical in English.
+# Feel free to keep using the previous wording in your language if it's already
+# the best one.
+# The second change is that we removed the period at the end of the phrase, because
+# it's not natural in our UI, and the underline was removed from this, so it doesn't
+# look like a link anymore. We suggest that everyone removes that period too.
+PluginClickToActivate2=Rhedeg %S
+PluginVulnerableUpdatable=Mae'r ategyn yma'n fregus a dylai gael ei ddiweddaru.
+PluginVulnerableNoUpdate=Mae diogelwch yr ategyn yma'n fregus.
+
+# Sanitize
+# LOCALIZATION NOTE (update.downloadAndInstallButton.label): %S is replaced by the
+# version of the update: "Update to 28.0".
+update.downloadAndInstallButton.label=Diweddaru %S
+update.downloadAndInstallButton.accesskey=D
+
+menuOpenAllInTabs.label=Agor pob Tab
+
+# History menu
+menuRestoreAllTabs.label=Adfer Pob Tab
+# LOCALIZATION NOTE (menuRestoreAllWindows, menuUndoCloseWindowLabel, menuUndoCloseWindowSingleTabLabel):
+# see bug 394759
+menuRestoreAllWindows.label=Adfer Pob Ffenestr
+# LOCALIZATION NOTE (menuUndoCloseWindowLabel): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 Window Title, #2 Number of tabs
+menuUndoCloseWindowLabel=#1 (a dim tabiau eraill);#1 (a #2 tab arall);#1 (a #2 dab arall);#1 (a #2 thab arall);#1 (a #2 tab arall);#1 (a #2 tab arall)
+menuUndoCloseWindowSingleTabLabel=#1
+
+# Unified Back-/Forward Popup
+tabHistory.current=Aros ar y dudalen hon
+tabHistory.goBack=Nôl i'r dudalen hon
+tabHistory.goForward=Mynd ymlaen i'r dudalen hon
+
+# URL Bar
+pasteAndGo.label=Gludo a Mynd
+# LOCALIZATION NOTE (reloadButton.tooltip):
+# %S is the keyboard shortcut for reloading the current page
+reloadButton.tooltip=Ail lwytho'r dudalen gyfredol (%S)
+# LOCALIZATION NOTE (stopButton.tooltip):
+# %S is the keyboard shortcut for stopping loading the page
+stopButton.tooltip=Peidio llwytho'r dudalen hon (%S)
+# LOCALIZATION NOTE (urlbar-zoom-button.tooltip):
+# %S is the keyboard shortcut for resetting the zoom level to 100%
+urlbar-zoom-button.tooltip=Ailosod lefel chwyddo (%S)
+# LOCALIZATION NOTE (reader-mode-button.tooltip):
+# %S is the keyboard shortcut for entering/exiting reader view
+reader-mode-button.tooltip=Toglo golwg darllenydd (%S)
+# LOCALIZATION NOTE (urlbar.placeholder):
+# %S is the name of the user's current search engine
+urlbar.placeholder=Chwilio gyda %S neu rhoi'r cyfeiriad yma
+
+# LOCALIZATION NOTE(zoom-button.label): %S is the current page zoom level,
+# %% will be displayed as a single % character (% is commonly used to define
+# format specifiers, so it needs to be escaped).
+zoom-button.label = %S%%
+
+# Block autorefresh
+refreshBlocked.goButton=Caniatáu
+refreshBlocked.goButton.accesskey=C
+refreshBlocked.refreshLabel=Rhwystrodd %S y dudalen hon rhag ailagor yn awtomatig.
+refreshBlocked.redirectLabel=Rhwystrodd %S y dudalen hon rhag ailgyfeirio i dudalen arall.
+
+# General bookmarks button
+# LOCALIZATION NOTE (bookmarksMenuButton.tooltip):
+# %S is the keyboard shortcut for "Show All Bookmarks"
+bookmarksMenuButton.tooltip=Dangos eich nodau tudalen (%S)
+
+# Downloads button tooltip
+# LOCALIZATION NOTE (downloads.tooltip):
+# %S is the keyboard shortcut for "Downloads"
+downloads.tooltip=Dangos cynnydd y llwytho i lawr cyfredol (%S)
+
+# Print button tooltip on OS X
+# LOCALIZATION NOTE (printButton.tooltip):
+# Use the unicode ellipsis char, \u2026,
+# or use "..." if \u2026 doesn't suit traditions in your locale.
+# %S is the keyboard shortcut for "Print"
+printButton.tooltip=Argraffu'r dudalen… (%S)
+
+# New Window button tooltip
+# LOCALIZATION NOTE (newWindowButton.tooltip):
+# %S is the keyboard shortcut for "New Window"
+newWindowButton.tooltip=Agor ffenestr newydd (%S)
+
+# New Tab button tooltip
+# LOCALIZATION NOTE (newTabButton.tooltip):
+# %S is the keyboard shortcut for "New Tab"
+newTabButton.tooltip=Agor tab newydd (%S)
+newTabContainer.tooltip=Agorwch dab newydd (%S)\nPwyso a'i ddal i agor tab cynhwysydd newydd
+newTabAlwaysContainer.tooltip=Dewiswch gynhwysydd i agor tab newydd
+
+# Offline web applications
+offlineApps.available2=A fyddwch yn caniatáu i %S gadw data ar eich cyfrifiadur?
+offlineApps.allowStoring.label=Caniatáu Cadw Data
+offlineApps.allowStoring.accesskey=C
+offlineApps.dontAllow.label=Peidio Caniatáu
+offlineApps.dontAllow.accesskey=P
+
+# Canvas permission prompt
+# LOCALIZATION NOTE (canvas.siteprompt): %S is hostname
+canvas.siteprompt=A fyddwch yn caniatáu i %S ddefnyddio eich data delwedd canfas HTML5? Gall hyn gael ei ddefnyddio i adnabod eich cyfrifiadur ei hun.
+canvas.notAllow=Peidio Caniatáu
+canvas.notAllow.accesskey=P
+canvas.allow=Caniatáu Myneidiad Data
+canvas.allow.accesskey=C
+canvas.remember=Cofio fy mhenderfyniad bob tro
+
+# WebAuthn prompts
+# LOCALIZATION NOTE (webauthn.registerPrompt2): %S is hostname
+webauthn.registerPrompt2=Mae %S eisiau cofrestru cyfrif gyda un o'ch allweddi diogelwch. Gallwch gysylltu ac awdurdodi un nawr neu ddileu.
+# LOCALIZATION NOTE (webauthn.registerDirectPrompt2):
+# %1$S is hostname. %2$S is brandShortName.
+# The website is asking for extended information about your
+# hardware authenticator that shouldn't be generally necessary. Permitting
+# this is safe if you only use one account at this website. If you have
+# multiple accounts at this website, and you use the same hardware
+# authenticator, then the website could link those accounts together.
+# And this is true even if you use a different profile / browser (or even Tor
+# Browser). To avoid this, you should use different hardware authenticators
+# for different accounts on this website.
+webauthn.registerDirectPrompt2=Mae %1$S yn gofyn am wybodaeth estynedig am eich allwedd diogelwch, all effeithio ar eich preifatrwydd.\n\nGall %2$S wneud hyn yn ddienw ar eich cyfer, ond efallai bydd y wefan yn gwrthod yr allwedd. Os fydd yn cael ei wrthod, gallwch wneud cais arall.
+# LOCALIZATION NOTE (webauthn.signPrompt2): %S is hostname
+webauthn.signPrompt2=Mae %S eisiau eich dilysu gan ddefnyddio allwedd diogelwch cofrestredig. Gallwch gysylltu a dilysu un nawr, neu ddiddymu.
+webauthn.cancel=Diddymu
+webauthn.cancel.accesskey=d
+webauthn.proceed=Ymlaen
+webauthn.proceed.accesskey=Y
+webauthn.anonymize=Gwneud yn anhysbys
+
+# Spoof Accept-Language prompt
+privacy.spoof_english=O bosib gall newid eich gosodiad i'r iaith Saesneg eich gwneud yn fwy anodd i'ch adnabod a gwella eich preifatrwydd. Hoffech chi wneud cais am fersiynau Saesneg o dudalennau gwe?
+
+# LOCALIZATION NOTE (identity.headerMainWithHost, identity.headerSecurityWithHost):
+# %S is the hostname of the site that is being displayed.
+identity.headerMainWithHost=Manylion gwefan %S
+identity.headerSecurityWithHost=Diogelwch Cysylltiad %S
+identity.identified.verifier=Dilyswyd gan: %S
+identity.identified.verified_by_you=Rydych wedi ychwanegu eithriad diogelwch ar gyfer y wefan hon.
+identity.identified.state_and_country=%S, %S
+identity.ev.contentOwner2=Tystysgrif wedi'i ryddhau i: %S
+
+# LOCALIZATION NOTE (identity.notSecure.label):
+# Keep this string as short as possible, this is displayed in the URL bar
+# use a synonym for "safe" or "private" if "secure" is too long.
+identity.notSecure.label=Dim yn Ddiogel
+identity.notSecure.tooltip=Nid yw'r cysylltiad yn ddiogel
+
+identity.extension.label=Estyniad (%S)
+identity.extension.tooltip=Llwythwyd gan estyniad: %S
+identity.showDetails.tooltip=Dangos manylion cysylltu
+
+# LOCALIZATION NOTE (contentBlocking.trackersView.blocked.label):
+#   This label is shown next to a tracker in the trackers subview.
+#   It forms the end of the (imaginary) sentence "www.example.com [was] Blocked"
+contentBlocking.trackersView.blocked.label=Rhwystrwyd
+
+contentBlocking.trackersView.empty.label=Dim wedi eu canfod ar y wefan hon
+
+# LOCALIZATION NOTE (contentBlocking.cookies.blockingTrackers.label, contentBlocking.cookies.blocking3rdParty.label,
+#   contentBlocking.cookies.blockingUnvisited.label,contentBlocking.cookies.blockingAll.label):
+contentBlocking.cookies.blockingTrackers3.label=Cwcis Tracio Traws-Gwefan
+contentBlocking.cookies.blocking3rdParty2.label=Cwcis Trydydd Parti
+contentBlocking.cookies.blockingUnvisited2.label=Cwcis Gwefan Heb Ymweliad
+contentBlocking.cookies.blockingAll2.label=Pob Cwci
+
+contentBlocking.cookiesView.firstParty.label=O'r Wefan Hon
+# LOCALIZATION NOTE (contentBlocking.cookiesView.firstParty.empty.label):
+#  This references the header from contentBlocking.cookiesView.firstParty.label:
+#  "[Cookies] From This Site: None detected on this site".
+contentBlocking.cookiesView.firstParty.empty.label=Dim wedi eu canfod ar y wefan hon
+
+contentBlocking.cookiesView.trackers2.label=Cwcis Tracio Traws-Gwefan
+# LOCALIZATION NOTE (contentBlocking.cookiesView.trackers.empty.label):
+#  This references the header from contentBlocking.cookiesView.trackers.label:
+#  "Tracking Cookies: None detected on this site".
+contentBlocking.cookiesView.trackers.empty.label=Dim wedi eu canfod ar y wefan hon
+
+contentBlocking.cookiesView.thirdParty.label=Cwcis Trydydd Parti
+# LOCALIZATION NOTE (contentBlocking.cookiesView.thirdParty.empty.label):
+#  This references the header from contentBlocking.cookiesView.thirdParty.label:
+#  "Third-Party Cookies: None detected on this site".
+contentBlocking.cookiesView.thirdParty.empty.label=Dim wedi eu canfod ar y wefan hon
+
+# LOCALIZATION NOTE (contentBlocking.cookiesView.allowed.label):
+#   This label is shown next to a cookie origin in the cookies subview.
+#   It forms the end of the (imaginary) sentence "www.example.com [was] Allowed"
+contentBlocking.cookiesView.allowed.label=Caniatawyd
+# LOCALIZATION NOTE (contentBlocking.cookiesView.blocked.label):
+#   This label is shown next to a cookie origin in the cookies subview.
+#   It forms the end of the (imaginary) sentence "www.example.com [was] Blocked"
+contentBlocking.cookiesView.blocked.label=Rhwystrwyd
+# LOCALIZATION NOTE (contentBlocking.cookiesView.removeButton.tooltip): %S is the domain of the site.
+contentBlocking.cookiesView.removeButton.tooltip=Clirio eithriad cwci heblaw %S
+
+# LOCALIZATION NOTE (contentBlocking.fingerprintersView.blocked.label):
+#   This label is shown next to a fingerprinter in the fingerprinters subview.
+#   It forms the end of the (imaginary) sentence "www.example.com [was] Blocked"
+contentBlocking.fingerprintersView.blocked.label=Rhwystrwyd
+
+# LOCALIZATION NOTE (contentBlocking.cryptominersView.blocked.label):
+#   This label is shown next to a cryptominer in the cryptominers subview.
+#   It forms the end of the (imaginary) sentence "www.example.com [was] Blocked"
+contentBlocking.cryptominersView.blocked.label=Rhwystrwyd
+
+trackingProtection.icon.activeTooltip2=Rhwystro tracwyr cyfryngau cymdeithasol, cwcis tracio ar draws-gwefannau, a bysbrintwyr.
+trackingProtection.icon.disabledTooltip2=Mae Diogelwch Uwch Rhag Tracio I FFWRDD ar y wefan hon.
+# LOCALIZATION NOTE (trackingProtection.icon.noTrackersDetectedTooltip): %S is brandShortName.
+trackingProtection.icon.noTrackersDetectedTooltip=Dim tracwyr hysbys i %S wedi eu canfod ar y dudalen hon.
+
+# LOCALIZATION NOTE (protections.header):
+# Header of the Protections Panel. %S is replaced with the site's hostname.
+protections.header=Diogelwch ar %S
+
+# LOCALIZATION NOTE (protections.disableAriaLabel):
+# Text that gets spoken by a screen reader if the button will disable protections.
+# %s is the site's hostname.
+protections.disableAriaLabel=Analluogi diogelu ar gyfer %S
+
+# LOCALIZATION NOTE (protections.enableAriaLabel):
+# Text that gets spoken by a screen reader if the button will enable protections.
+# %s is the site's hostname.
+protections.enableAriaLabel=Galluogi diogelu ar gyfer %S
+
+# Blocking and Not Blocking sub-views in the Protections Panel
+protections.blocking.fingerprinters.title=Bysbrintwyr wedi'u rhwystro
+protections.blocking.cryptominers.title=Cryptogloddwyr wedi'u Rhwystro
+protections.blocking.cookies.trackers.title=Cwcis Tracio Traws-Gwefan wedi'u Rhwystro
+protections.blocking.cookies.3rdParty.title=Cwcis Trydydd Parti wedi'u Rhwystro
+protections.blocking.cookies.all.title=Pob Cwci wedi eu Rhwystro
+protections.blocking.cookies.unvisited.title=Cwcis Gwefan Heb Ymweliad wedi'u Rhwystro
+protections.blocking.trackingContent.title=Cynnwys Tracio wedi'u Rhwystro
+protections.blocking.socialMediaTrackers.title=Tracwyr Cyfryngau Cymdeithasol wedi'u Rhwystro
+protections.notBlocking.fingerprinters.title=Ddim yn Rhwystro Bysbrintwyr
+protections.notBlocking.cryptominers.title=Ddim yn Rhwystro Cryptogloddwyr
+protections.notBlocking.cookies.3rdParty.title=Ddim Yn Rhwystro Cwcis Trydydd Parti
+protections.notBlocking.cookies.all.title=Ddim yn Rhwystro Cwcis
+protections.notBlocking.crossSiteTrackingCookies.title=Ddim yn Rhwystro Cwcis Tracio Traws Gwefan
+protections.notBlocking.trackingContent.title=Ddim yn Rhwystro Cynnwys Tracio
+protections.notBlocking.socialMediaTrackers.title=Ddim yn Rhwystro Tracwyr Cyfryngau Cymdeithasol
+
+# Footer section in the Protections Panel
+# LOCALIZATION NOTE (protections.footer.blockedTrackerCounter.description,
+# protections.footer.blockedTrackerCounter.tooltip):
+#   This text indicates the total number of trackers blocked on all sites. In
+#   its tooltip, we show the date when we started counting this number.
+# LOCALIZATION NOTE (protections.footer.blockedTrackerCounter.description):
+#   Semicolon-separated list of plural forms.
+#   See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+#   Replacement for #1 is a locale-string converted positive integer.
+protections.footer.blockedTrackerCounter.description=1 Wedi'u Rhwystro;#1 Wedi'i Rwystro;#1 Wedi'u Rhwystro;#1 Wedi'u Rhwystro;#1 Wedi'u Rhwystro;#1 Wedi'u Rhwystro
+# LOCALIZATION NOTE (protections.footer.blockedTrackerCounter.tooltip):
+#   %S is the date on which we started counting (e.g., July 17, 2019).
+protections.footer.blockedTrackerCounter.tooltip=Ers %S
+
+# Milestones section in the Protections Panel
+# LOCALIZATION NOTE (protections.milestone.description):
+#   Semicolon-separated list of plural forms.
+#   See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+#   #1 is replaced with brandShortName.
+#   #2 is replaced with the (locale-formatted) number of trackers blocked
+#   #3 is replaced by a locale-formatted date with short month and numeric year.
+#   In English this looks like "Firefox blocked over 10,000 trackers since Oct 2019"
+protections.milestone.description=Mae #1 wedi rhwystro #2 traciwr ers #3;Mae #1 wedi rhwystro #2 traciwr ers #3;Mae #1 wedi rhwystro #2 draciwr ers #3;Mae #1 wedi rhwystro #2 traciwr ers #3;Mae #1 wedi rhwystro #2 traciwr ers #3;Mae #1 wedi rhwystro #2 traciwr ers #3
+
+# Edit Bookmark UI
+editBookmarkPanel.newBookmarkTitle=Nod Tudalen Newydd
+editBookmarkPanel.editBookmarkTitle=Golygu'r Nod Tudalen
+editBookmarkPanel.cancel.label=Diddymu
+editBookmarkPanel.cancel.accesskey=D
+
+# LOCALIZATION NOTE (editBookmark.removeBookmarks.label): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Replacement for #1 is the number of bookmarks to be removed.
+# If this causes problems with localization you can also do "Remove Bookmarks (#1)"
+# instead of "Remove #1 Bookmarks".
+editBookmark.removeBookmarks.label=Dileu dim Nodau Tudalen;Dileu #1 Nod Tudalen;Dileu #1 Nod Tudalen;Dileu #1 Nod Tudalen;Dileu #1 Nod Tudalen;Dileu #1 Nod Tudalen
+editBookmark.removeBookmarks.accesskey=T
+
+# Application menu
+
+# LOCALIZATION NOTE(zoomReduce-button.tooltip): %S is the keyboard shortcut.
+zoomReduce-button.tooltip = Chwyddo allan (%S)
+# LOCALIZATION NOTE(zoomReset-button.tooltip): %S is the keyboard shortcut.
+zoomReset-button.tooltip = Ailosod lefel chwyddo (%S)
+# LOCALIZATION NOTE(zoomEnlarge-button.tooltip): %S is the keyboard shortcut.
+zoomEnlarge-button.tooltip = Chwyddo i mewn (%S)
+
+# LOCALIZATION NOTE (cut-button.tooltip): %S is the keyboard shortcut.
+cut-button.tooltip = Torri (%S)
+# LOCALIZATION NOTE (copy-button.tooltip): %S is the keyboard shortcut.
+copy-button.tooltip = Copïo (%S)
+# LOCALIZATION NOTE (paste-button.tooltip): %S is the keyboard shortcut.
+paste-button.tooltip = Gludo (%S)
+
+# Geolocation UI
+
+geolocation.allowLocation=Caniatáu Mynediad i Leoliad
+geolocation.allowLocation.accesskey=A
+geolocation.dontAllowLocation=Peidio Caniatáu
+geolocation.dontAllowLocation.accesskey=P
+geolocation.shareWithSite3=A fyddwch yn caniatáu i %S gael mynediad i'ch lleoliad?
+geolocation.shareWithFile3=A fyddwch yn caniatáu i'r ffeil leol gael mynediad i'ch lleoliad?
+# LOCALIZATION NOTE(geolocation.shareWithSiteUnsafeDelegation):
+# %1$S is the first party origin, %2$S is the third party origin.
+geolocation.shareWithSiteUnsafeDelegation=A wnewch chi adael i %1$S roi caniatâd i %2$S gael mynediad i'ch lleoliad?
+geolocation.remember=Cofio'r penderfyniad yma
+
+# Virtual Reality Device UI
+xr.allow=Caniatáu Mynediad Rhithrealaeth
+xr.allow.accesskey=C
+xr.dontAllow=Peidio Caniatáu
+xr.dontAllow.accesskey=P
+xr.shareWithSite3=A wnewch chi ganiatáu i %S gael mynediad at ddyfeisiau rhithrealaeth? Gall hyn ddatgelu gwybodaeth sensitif.
+xr.shareWithFile3=A wnewch chi ganiatáu i %S gael mynediad at ddyfeisiau rhithrealaeth? Gall hyn ddatgelu gwybodaeth sensitif.
+xr.remember=Cofio'r penderfyniad yma
+
+# Persistent storage UI
+persistentStorage.allow=Caniatáu
+persistentStorage.allow.accesskey=C
+persistentStorage.neverAllow.label=Byth Caniatáu
+persistentStorage.neverAllow.accesskey=B
+persistentStorage.notNow.label=Nid Nawr
+persistentStorage.notNow.accesskey=N
+persistentStorage.allowWithSite=A wnewch chi ganiatáu i %S gadw data mewn storfa barhaus?
+
+webNotifications.allow=Caniatáu Hysbysiadau
+webNotifications.allow.accesskey=A
+webNotifications.notNow=Nid Nawr
+webNotifications.notNow.accesskey=n
+webNotifications.never=Byth Caniatáu
+webNotifications.never.accesskey=b
+webNotifications.receiveFromSite2=A fyddwch yn caniatáu i %S anfon hysbysiadau?
+
+# Phishing/Malware Notification Bar.
+# LOCALIZATION NOTE (notADeceptiveSite, notAnAttack)
+# The two button strings will never be shown at the same time, so
+# it's okay for them to have the same access key
+safebrowsing.getMeOutOfHereButton.label=Allan o fan hyn!
+safebrowsing.getMeOutOfHereButton.accessKey=A
+safebrowsing.deceptiveSite=Gwefan Twyllodrus!
+safebrowsing.notADeceptiveSiteButton.label=Nid yw hon yn wefan twyllodrus…
+safebrowsing.notADeceptiveSiteButton.accessKey=t
+safebrowsing.reportedAttackSite=Gwefan Ymosod Hysbys!
+safebrowsing.notAnAttackButton.label=Nid gwefan ymosodiad yw hwn…
+safebrowsing.notAnAttackButton.accessKey=y
+safebrowsing.reportedUnwantedSite=Gwefan Meddalwedd Digroeso Hysbys!
+safebrowsing.reportedHarmfulSite=Gwefan Niweidiol Hysbys!
+
+# Ctrl-Tab
+# LOCALIZATION NOTE (ctrlTab.listAllTabs.label): #1 represents the number
+# of tabs in the current browser window. It will always be 2 at least.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+ctrlTab.listAllTabs.label=Rhestru Dim Tabiau;Rhestru pob un o'r #1 Tab;Rhestru Pob un o'r #1 Dab;Rhestru Pob un o'r #1 Thab;Rhestru Pob un o'r #1 Tab;Rhestru Pob un o'r #1 Tab
+
+# LOCALIZATION NOTE (addKeywordTitleAutoFill): %S will be replaced by the page's title
+# Used as the bookmark name when saving a keyword for a search field.
+addKeywordTitleAutoFill=Chwilio %S
+
+# safeModeRestart
+safeModeRestartPromptTitle=Ailgychwyn gyda'r Ychwanegyn wedi ei Analluogi
+safeModeRestartPromptMessage=Ydych chi'n siŵr eich bod am analluogi pob ychwanegyn ac ailgychwyn?
+safeModeRestartButton=Ailgychwyn
+
+# LOCALIZATION NOTE (browser.menu.showCharacterEncoding): Set to the string
+# "true" (spelled and capitalized exactly that way) to show the "Text
+# Encoding" menu in the main Firefox button on Windows. Any other value will
+# hide it. Regardless of the value of this setting, the "Text Encoding"
+# menu will always be accessible via the "Web Developer" menu.
+# This is not a string to translate; it just controls whether the menu shows
+# up in the Firefox button. If users frequently use the "Text Encoding"
+# menu, set this to "true". Otherwise, you can leave it as "false".
+browser.menu.showCharacterEncoding=false
+
+# Mozilla data reporting notification (Telemetry, Firefox Health Report, etc)
+dataReportingNotification.message       = Mae %1$S yn anfon peth data yn awtomatig i %2$S fel bod modd i ni wella eich profiad.
+dataReportingNotification.button.label  = Dewis Beth Rwy'n Rhannu
+dataReportingNotification.button.accessKey  = D
+
+# Process hang reporter
+processHang.label = Mae tudalen gwe'n achosi i'ch porwr redeg yn araf. Beth hoffech chi ei wneud?
+# LOCALIZATION NOTE (processHang.add-on.label): %1$S is the name of the
+# extension. %2$S is the name of the product (e.g., Firefox)
+processHang.add-on.label = Mae'r sgript yn estyniad “%1$S” yn achosi i %2$S arafu.
+processHang.add-on.learn-more.text = Dysgu rhagor
+processHang.button_stop.label = Ei Hatal
+processHang.button_stop.accessKey = H
+processHang.button_stop_sandbox.label = Analluogi Estyniadau Dros dro ar y Dudalen
+processHang.button_stop_sandbox.accessKey = A
+processHang.button_wait.label = Aros
+processHang.button_wait.accessKey = A
+processHang.button_debug.label = Sgript Dadfygio
+processHang.button_debug.accessKey = S
+
+# LOCALIZATION NOTE (fullscreenButton.tooltip): %S is the keyboard shortcut for full screen
+fullscreenButton.tooltip=Dangos y ffenestr yn y sgrin lawn (%S)
+
+# These are visible when opening the popup inside the bookmarks sidebar
+sidebar.moveToLeft=Symud y Bar Ochr i'r Chwith
+sidebar.moveToRight=Symud y Bar Ochr i'r Dde
+
+# LOCALIZATION NOTE (getUserMedia.shareCamera2.message,
+#                    getUserMedia.shareMicrophone2.message,
+#                    getUserMedia.shareScreen3.message,
+#                    getUserMedia.shareCameraAndMicrophone2.message,
+#                    getUserMedia.shareCameraAndAudioCapture2.message,
+#                    getUserMedia.shareScreenAndMicrophone3.message,
+#                    getUserMedia.shareScreenAndAudioCapture3.message,
+#                    getUserMedia.shareAudioCapture2.message):
+# %S is the website origin (e.g. www.mozilla.org)
+getUserMedia.shareCamera2.message = A fyddwch yn caniatáu i %S ddefnyddio eich camera?
+getUserMedia.shareMicrophone2.message = A fyddwch yn caniatáu i %S ddefnyddio eich meicroffon?
+getUserMedia.shareScreen3.message = A fyddwch yn caniatáu i %S weld eich sgrin?
+getUserMedia.shareCameraAndMicrophone2.message = A fyddwch yn caniatáu i %S ddefnyddio eich camera a'ch meicroffon?
+getUserMedia.shareCameraAndAudioCapture2.message = A fyddwch yn caniatáu i %S ddefnyddio eich camera a gwrando ar sain y tab yma?
+getUserMedia.shareScreenAndMicrophone3.message = A fyddwch yn caniatáu i %S ddefnyddio eich meicroffon a gweld eich sgrin?
+getUserMedia.shareScreenAndAudioCapture3.message = A fyddwch yn caniatáu i %S wrando ar sain y tab yma a gweld eich sgrin?
+getUserMedia.shareAudioCapture2.message = A fyddwch yn caniatáu i %S wrando ar sain y tab yma?
+
+# LOCALIZATION NOTE (getUserMedia.shareCameraUnsafeDelegation.message,
+#                    getUserMedia.shareMicrophoneUnsafeDelegation.message,
+#                    getUserMedia.shareScreenUnsafeDelegation.message,
+#                    getUserMedia.shareCameraAndMicrophoneUnsafeDelegation.message,
+#                    getUserMedia.shareCameraAndAudioCaptureUnsafeDelegation.message,
+#                    getUserMedia.shareScreenAndMicrophoneUnsafeDelegation.message,
+#                    getUserMedia.shareScreenAndAudioCaptureUnsafeDelegation.message,
+# %1$S is the first party origin.
+# %2$S is the third party origin.
+getUserMedia.shareCameraUnsafeDelegation.message = A wnewch chi adael i %1$S roi mynediad i %2$S i'ch camera?
+getUserMedia.shareMicrophoneUnsafeDelegations.message = A wnewch chi adael i %1$S roi mynediad i %2$S i'ch meicroffon?
+getUserMedia.shareScreenUnsafeDelegation.message = A wnewch chi adael i %1$S roi caniatâd i %2$S weld eich sgrin?
+getUserMedia.shareCameraAndMicrophoneUnsafeDelegation.message = A wnewch chi adael i %1$S roi mynediad i %2$S i'ch camera a'ch meicroffon?
+getUserMedia.shareCameraAndAudioCaptureUnsafeDelegation.message = A wnewch chi adael i %1$S roi mynediad i %2$S i'ch camera a gwrando ar sain y tab hwn?
+getUserMedia.shareScreenAndMicrophoneUnsafeDelegation.message = A wnewch chi adael i %1$S roi mynediad i%2$S i'ch meicroffon a gweld eich sgrin?
+getUserMedia.shareScreenAndAudioCaptureUnsafeDelegation.message = A wnewch chi adael i %1$S roi caniatâd i %2$S wrando ar sain y tab hwn a gweld eich sgrin?
+
+# LOCALIZATION NOTE (getUserMedia.shareScreenWarning.message): NB: inserted via innerHTML, so please don't use <, > or & in this string.
+# %S will be the 'learn more' link
+getUserMedia.shareScreenWarning.message = Rhannwch sgriniau dim ond gyda gwefannau rydych yn ymddiried ynddynt. Gall rannu ganiatáu i wefannau twyllodrus bori fel chi a dwyn eich data preifat. %S
+# LOCALIZATION NOTE (getUserMedia.shareFirefoxWarning.message): NB: inserted via innerHTML, so please don't use <, > or & in this string.
+# %1$S is brandShortName (eg. Firefox)
+# %2$S will be the 'learn more' link
+getUserMedia.shareFirefoxWarning.message = Rhannwch %1$S dim ond gyda gwefannau rydych yn ymddiried ynddynt. Gall rannu ganiatáu i wefannau twyllodrus bori fel chi a dwyn eich data preifat. %2$S
+# LOCALIZATION NOTE(getUserMedia.shareScreen.learnMoreLabel): NB: inserted via innerHTML, so please don't use <, > or & in this string.
+getUserMedia.shareScreen.learnMoreLabel = Dysgu Rhagor
+getUserMedia.selectWindowOrScreen.label=Ffenestr neu Sgrin i'w rannu:
+getUserMedia.selectWindowOrScreen.accesskey=F
+getUserMedia.pickWindowOrScreen.label = Dewiswch Ffenestr neu Sgrin
+getUserMedia.shareEntireScreen.label = Sgrin gyfan
+getUserMedia.sharePipeWirePortal.label = Defnyddio gosodiadau'r system weithredu
+# LOCALIZATION NOTE (getUserMedia.shareMonitor.label):
+# %S is screen number (digits 1, 2, etc)
+# Example: Screen 1, Screen 2,..
+getUserMedia.shareMonitor.label = Sgrin %S
+# LOCALIZATION NOTE (getUserMedia.shareApplicationWindowCount.label):
+# Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Replacement for #1 is the name of the application.
+# Replacement for #2 is the number of windows currently displayed by the application.
+getUserMedia.shareApplicationWindowCount.label=#1 (Dim ffenestri);#1 (#2 ffenestr);#1 (#2 ffenestr);#1 (#2 ffenestr);#1 (#2 ffenestr);#1 (#2 ffenestr)
+# LOCALIZATION NOTE (getUserMedia.allow.label,
+#                    getUserMedia.dontAllow.label):
+# These two buttons are the possible answers to the various prompts in the
+# "getUserMedia.share{device}.message" strings.
+getUserMedia.allow.label = Caniatáu
+getUserMedia.allow.accesskey = C
+getUserMedia.dontAllow.label = Peidio Caniatáu
+getUserMedia.dontAllow.accesskey = P
+getUserMedia.remember=Cofio'r penderfyniad yma
+# LOCALIZATION NOTE (getUserMedia.reasonForNoPermanentAllow.screen3,
+#                    getUserMedia.reasonForNoPermanentAllow.audio,
+#                    getUserMedia.reasonForNoPermanentAllow.insecure):
+# %S is brandShortName
+getUserMedia.reasonForNoPermanentAllow.screen3=Nid yw %S yn caniatáu mynediad parhaus i'ch sgrin.
+getUserMedia.reasonForNoPermanentAllow.audio=Nid yw %S yn gallu caniatáu mynediad parhaol i sain eich tab heb ofyn pa dab i'w rannu.
+getUserMedia.reasonForNoPermanentAllow.insecure=Nid yw eich cysylltiad a'r wefan hon y ddiogel. Er mwyn eich diogelu, dim ond ar gyfer y sesiwn yma y bydd %S yn caniatáu mynediad.
+
+getUserMedia.sharingMenu.label = Tabiau dyfeisiau sy'n rhannu
+getUserMedia.sharingMenu.accesskey = d
+# LOCALIZATION NOTE (getUserMedia.sharingMenuCamera
+#                    getUserMedia.sharingMenuMicrophone,
+#                    getUserMedia.sharingMenuAudioCapture,
+#                    getUserMedia.sharingMenuApplication,
+#                    getUserMedia.sharingMenuScreen,
+#                    getUserMedia.sharingMenuWindow,
+#                    getUserMedia.sharingMenuBrowser,
+#                    getUserMedia.sharingMenuCameraMicrophone,
+#                    getUserMedia.sharingMenuCameraMicrophoneApplication,
+#                    getUserMedia.sharingMenuCameraMicrophoneScreen,
+#                    getUserMedia.sharingMenuCameraMicrophoneWindow,
+#                    getUserMedia.sharingMenuCameraMicrophoneBrowser,
+#                    getUserMedia.sharingMenuCameraAudioCapture,
+#                    getUserMedia.sharingMenuCameraAudioCaptureApplication,
+#                    getUserMedia.sharingMenuCameraAudioCaptureScreen,
+#                    getUserMedia.sharingMenuCameraAudioCaptureWindow,
+#                    getUserMedia.sharingMenuCameraAudioCaptureBrowser,
+#                    getUserMedia.sharingMenuCameraApplication,
+#                    getUserMedia.sharingMenuCameraScreen,
+#                    getUserMedia.sharingMenuCameraWindow,
+#                    getUserMedia.sharingMenuCameraBrowser,
+#                    getUserMedia.sharingMenuMicrophoneApplication,
+#                    getUserMedia.sharingMenuMicrophoneScreen,
+#                    getUserMedia.sharingMenuMicrophoneWindow,
+#                    getUserMedia.sharingMenuMicrophoneBrowser,
+#                    getUserMedia.sharingMenuAudioCaptureApplication,
+#                    getUserMedia.sharingMenuAudioCaptureScreen,
+#                    getUserMedia.sharingMenuAudioCaptureWindow,
+#                    getUserMedia.sharingMenuAudioCaptureBrowser):
+# %S is the website origin (e.g. www.mozilla.org)
+getUserMedia.sharingMenuCamera = %S (camera)
+getUserMedia.sharingMenuMicrophone = %S (meicroffon)
+getUserMedia.sharingMenuAudioCapture = %S (tab sain)
+getUserMedia.sharingMenuApplication = %S (rhaglen)
+getUserMedia.sharingMenuScreen = %S (sgrin)
+getUserMedia.sharingMenuWindow = %S (ffenestr)
+getUserMedia.sharingMenuBrowser = %S (tab)
+getUserMedia.sharingMenuCameraMicrophone = %S (camera a meicroffon)
+getUserMedia.sharingMenuCameraMicrophoneApplication = %S (camera, meicroffon a rhaglen)
+getUserMedia.sharingMenuCameraMicrophoneScreen = %S (camera, meicroffon a sgrin)
+getUserMedia.sharingMenuCameraMicrophoneWindow = %S (camera, meicroffon a ffenestr)
+getUserMedia.sharingMenuCameraMicrophoneBrowser = %S (camera, meicroffon a thab)
+getUserMedia.sharingMenuCameraAudioCapture = %S (camera a thab sain)
+getUserMedia.sharingMenuCameraAudioCaptureApplication = %S (camera, tab sain a rhaglen)
+getUserMedia.sharingMenuCameraAudioCaptureScreen = %S (camera, tab sain a sgrin)
+getUserMedia.sharingMenuCameraAudioCaptureWindow = %S (camera, tab sain a ffenestr)
+getUserMedia.sharingMenuCameraAudioCaptureBrowser = %S (camera, tab sain a thab)
+getUserMedia.sharingMenuCameraApplication = %S (camera a rhaglen)
+getUserMedia.sharingMenuCameraScreen = %S (camera a sgrin)
+getUserMedia.sharingMenuCameraWindow = %S (camera a ffenestr)
+getUserMedia.sharingMenuCameraBrowser = %S (camera a thab)
+getUserMedia.sharingMenuMicrophoneApplication = %S (meicroffon a rhaglen)
+getUserMedia.sharingMenuMicrophoneScreen = %S (meicroffon a sgrin)
+getUserMedia.sharingMenuMicrophoneWindow = %S (meicroffon a ffenestr)
+getUserMedia.sharingMenuMicrophoneBrowser = %S (meicroffon a thab)
+getUserMedia.sharingMenuAudioCaptureApplication = %S (tab sain a rhaglen)
+getUserMedia.sharingMenuAudioCaptureScreen = %S (tab sain a sgrin)
+getUserMedia.sharingMenuAudioCaptureWindow = %S (tab sain a ffenestr)
+getUserMedia.sharingMenuAudioCaptureBrowser = %S (tab sain a thab)
+# LOCALIZATION NOTE(getUserMedia.sharingMenuUnknownHost): this is used for the website
+# origin for the sharing menu if no readable origin could be deduced from the URL.
+getUserMedia.sharingMenuUnknownHost = Tarddiad anhysbys
+
+# LOCALIZATION NOTE(emeNotifications.drmContentPlaying.message2): %S is brandShortName.
+emeNotifications.drmContentPlaying.message2 = Mae peth sain a fideo ar y wefan yn defnyddio meddalwedd DRM, gall gyfyngu'r hyn y gall %S ei wneud gydag ef.
+emeNotifications.drmContentPlaying.button.label = Ffurfweddu…
+emeNotifications.drmContentPlaying.button.accesskey = F
+
+# LOCALIZATION NOTE(emeNotifications.drmContentDisabled.message): NB: inserted via innerHTML, so please don't use <, > or & in this string. %S will be the 'learn more' link
+emeNotifications.drmContentDisabled.message = Rhaid galluogi DRM i chwarae peth sain neu fideo ar y dudalen hon. %S
+emeNotifications.drmContentDisabled.button.label = Galluogi DRM
+emeNotifications.drmContentDisabled.button.accesskey = G
+# LOCALIZATION NOTE(emeNotifications.drmContentDisabled.learnMoreLabel): NB: inserted via innerHTML, so please don't use <, > or & in this string.
+emeNotifications.drmContentDisabled.learnMoreLabel = Dysgu Rhagor
+
+# LOCALIZATION NOTE(emeNotifications.drmContentCDMInstalling.message): NB: inserted via innerHTML, so please don't use <, > or & in this string. %S is brandShortName
+emeNotifications.drmContentCDMInstalling.message = Mae %S yn gosod cydrannau sydd eu hangen i chwarae'r sain a'r fideo ar y dudalen hon. Ceisiwch eto'n hwyrach ymlaen.
+
+emeNotifications.unknownDRMSoftware = Anhysbys
+
+# LOCALIZATION NOTE - %S is brandShortName
+slowStartup.message = Mae %S i weld yn araf… i… gychwyn.
+slowStartup.helpButton.label = Dysgu Sut Mae ei Gyflymu
+slowStartup.helpButton.accesskey = D
+slowStartup.disableNotificationButton.label = Peidio â Dweud Wrthyf Eto
+slowStartup.disableNotificationButton.accesskey = W
+
+# LOCALIZATION NOTE  - %S is brandShortName
+flashHang.message = Mae %S wedi newid rhai o osodiadau Adobe Flash er mwyn gwella perfformiad.
+flashHang.helpButton.label = Dysgu Rhagor…
+flashHang.helpButton.accesskey = D
+
+# LOCALIZATION NOTE (customizeMode.tabTitle): %S is brandShortName
+customizeMode.tabTitle = Cyfaddasu %S
+
+e10s.accessibilityNotice.acceptButton.label = Iawn
+e10s.accessibilityNotice.acceptButton.accesskey = I
+
+# LOCALIZATION NOTE (e10s.accessibilityNotice.jawsMessage): %S is brandShortName
+e10s.accessibilityNotice.jawsMessage = Mae dangos cynnwys tabiau wedi ei analluogi oherwydd anghydnawsedd rhwng %S â'ch meddalwedd hygyrchedd. Diweddarwch eich darllenydd sgrin neu newidiwch i Firefox Extended Support Release.
+
+# LOCALIZATION NOTE (userContextPersonal.label,
+#                    userContextWork.label,
+#                    userContextShopping.label,
+#                    userContextBanking.label,
+#                    userContextNone.label):
+# These strings specify the four predefined contexts included in support of the
+# Contextual Identity / Containers project. Each context is meant to represent
+# the context that the user is in when interacting with the site. Different
+# contexts will store cookies and other information from those sites in
+# different, isolated locations. You can enable the feature by typing
+# about:config in the URL bar and changing privacy.userContext.enabled to true.
+# Once enabled, you can open a new tab in a specific context by clicking
+# File > New Container Tab > (1 of 4 contexts). Once opened, you will see these
+# strings on the right-hand side of the URL bar.
+userContextPersonal.label = Personol
+userContextWork.label = Gwaith
+userContextBanking.label = Bancio
+userContextShopping.label = Siopa
+userContextNone.label = Dim Cynhwysydd
+
+userContextPersonal.accesskey = P
+userContextWork.accesskey = G
+userContextBanking.accesskey = B
+userContextShopping.accesskey = S
+userContextNone.accesskey = D
+
+userContext.aboutPage.label = Rheoli cynhwysyddion
+userContext.aboutPage.accesskey = y
+
+userContextOpenLink.label = Agor Dolen mewn Tab %S Newydd
+
+muteTab.label = Tewi Tab
+muteTab.accesskey = T
+unmuteTab.label = Tab Dad-dewi
+unmuteTab.accesskey = D
+playTab.label = Chwarae'r Tab
+playTab.accesskey = h
+
+muteSelectedTabs2.label = Tewi Tabiau
+# LOCALIZATION NOTE (muteSelectedTabs2.accesskey): The accesskey should
+# match the accesskey for muteTab.accesskey
+muteSelectedTabs2.accesskey = T
+unmuteSelectedTabs2.label = Dad-dewi Tabiau
+# LOCALIZATION NOTE (unmuteSelectedTabs2.accesskey): The accesskey should
+# match the accesskey for unmuteTab.accesskey
+unmuteSelectedTabs2.accesskey = t
+playTabs.label = Chwarae Tabiau
+playTabs.accesskey = C
+
+# LOCALIZATION NOTE (sendTabsToDevice.label):
+# Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs sent to the device.
+sendTabsToDevice.label = Anfon Tab i Ddyfais;Anfon #1 Tab i Ddyfais;Anfon #1 Dab i Ddyfais;Anfon #1 Thab i Ddyfais;Anfon #1 Tab i Ddyfais;Anfon #1 Thab i Ddyfais
+sendTabsToDevice.accesskey = n
+
+# LOCALIZATION NOTE (pageAction.sendTabsToDevice.label):
+# Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs sent to the device.
+pageAction.sendTabsToDevice.label = Anfon Tab i Ddyfais;Anfon #1 Tab i Ddyfais;Anfon #1 Dab i Ddyfais;Anfon #1 Thab i Ddyfais;Anfon #1 Tab i Ddyfais;Anfon #1 Thab i Ddyfais
+
+# LOCALIZATION NOTE (pendingCrashReports2.label): Semi-colon list of plural forms
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of pending crash reports
+pendingCrashReports2.label = Nid oes gennych adroddiad chwalu sydd heb ei gyflwyno;Mae gennych #1 adroddiad chwalu sydd heb ei gyflwyno;Mae gennych #1 adroddiad chwalu sydd heb eu cyflwyno;Mae gennych #1 adroddiad chwalu sydd heb eu cyflwyno;Mae gennych #1 adroddiad chwalu sydd heb eu cyflwyno;Mae gennych #1 adroddiad chwalu sydd heb eu cyflwyno
+pendingCrashReports.viewAll = Gweld
+pendingCrashReports.send = Anfon
+pendingCrashReports.alwaysSend = Anfon Bob Tro
+
+decoder.noCodecs.button = Sut mae gwneud
+decoder.noCodecs.accesskey = D
+decoder.noCodecsLinux.message = I chwarae fideo, efallai y bydd angen gosod y codecsau fideo angenrheidiol.
+decoder.noHWAcceleration.message = I wella ansawdd y fideo, efallai y bydd angen gosod y Microsoft Media Feature Pack.
+decoder.noPulseAudio.message = I chwarae sain, efallai y bydd angen gosod y feddalwedd PulseAudio angenrheidiol.
+decoder.unsupportedLibavcodec.message = Gall libavcodec fod yn fregus neu heb ei gynnal a dylai gael ei ddiweddaru ar gyfer chwarae fideo.
+
+decoder.decodeError.message = Digwyddodd gwall wrth ddadgodio adnodd cyfrwng.
+decoder.decodeError.button = Adrodd ar Fater Gwefan
+decoder.decodeError.accesskey = A
+decoder.decodeWarning.message = Digwyddodd gwall adferadwy wrth ddadgodio adnodd cyfrwng.
+
+# LOCALIZATION NOTE (captivePortal.infoMessage3):
+# Shown in a notification bar when we detect a captive portal is blocking network access
+# and requires the user to log in before browsing.
+captivePortal.infoMessage3 = Rhaid i chi fewngofnodi i'r rhwydwaith hwn cyn i chi gael mynediad i'r Rhyngrwyd.
+# LOCALIZATION NOTE (captivePortal.showLoginPage2):
+# The label for a button shown in the info bar in all tabs except the login page tab.
+# The button shows the portal login page tab when clicked.
+captivePortal.showLoginPage2 = Agor Tudalen Mewngofnodi i'r Rhwydwaith
+
+permissions.remove.tooltip = Clirio'r caniatâd a gofyn eto
+
+permissions.fullscreen.promptCanceled = Diddymu ceisiadau am ganiatâd: peidiwch cyhoeddi ceisiadau am ganiatâd cyn mynd i mewn i sgrin lawn DOM.
+permissions.fullscreen.fullScreenCanceled = Sgrin lawn DOM wedi'u Gadael: peidiwch cyhoeddi ceisiadau am ganiatâd tra ar sgrin lawn DOM.
+
+# LOCALIZATION NOTE (aboutDialog.architecture.*):
+# The sixtyFourBit and thirtyTwoBit strings describe the architecture of the
+# current Firefox build: 32-bit or 64-bit. These strings are used in parentheses
+# between the Firefox version and the "What's new" link in the About dialog,
+# e.g.: "48.0.2 (32-bit) <What's new>" or "51.0a1 (2016-09-05) (64-bit)".
+aboutDialog.architecture.sixtyFourBit = 64 did
+aboutDialog.architecture.thirtyTwoBit = 32 did
+
+# LOCALIZATION NOTE (certImminentDistrust.message):
+# Shown in the browser console when visiting a website that is trusted today,
+# but won't be in the future unless the site operator makes a change.
+certImminentDistrust.message = Fyddwn ni ddim yn ymddiried yn y dystysgrif diogelwch sy'n cael ei defnyddio ar y wefan hon mewn fersiynau i'r dyfodol. Am ragor o wybodaeth, ewch i https://wiki.mozilla.org/CA/Upcoming_Distrust_Actions
+
+midi.Allow.label = Caniatáu
+midi.Allow.accesskey = n
+midi.DontAllow.label = Peidio Caniatáu
+midi.DontAllow.accesskey = P
+midi.remember=Cofio'r penderfyniad yma
+midi.shareWithFile.message = A fyddwch yn caniatáu i'r ffeil leol gael mynediad i'ch Dyfeisiau MIDI?
+# LOCALIZATION NOTE (midi.shareWithSite.message): %S is the name of the site URL (https://...) requesting MIDI access
+midi.shareWithSite.message = A fyddwch yn caniatáu i %S gael mynediad i'ch Dyfeisiau MIDI?
+midi.shareSysexWithFile.message = A wnewch chi ganiatáu i'r ffeil lleol hon i gael mynediad i'ch dyfeisiau MIDI ac anfon/derbyn negeseuon SysEx?
+# LOCALIZATION NOTE (midi.shareSysexWithSite.message): %S is the name of the site URL (https://...) requesting MIDI access
+midi.shareSysexWithSite.message = A wnewch chi ganiatáu i %S gael mynediad i'ch dyfeisiau MIDI ac anfon/derbyn negeseuon SysEx?
+
+# LOCALIZATION NOTE (panel.back):
+# This is used by screen readers to label the "back" button in various browser
+# popup panels, including the sliding subviews of the main menu.
+panel.back = Nôl
+
+storageAccess.Allow.label = Caniatáu Mynediad
+storageAccess.Allow.accesskey = C
+storageAccess.DontAllow.label = Rhwystro Mynediad
+storageAccess.DontAllow.accesskey = R
+# LOCALIZATION NOTE (storageAccess2.message):
+# %1$S is the name of the site URL (www.site1.example) trying to track the user's activity.
+# %2$S is the name of the site URL (www.site2.example) that the user is visiting.  This is the same domain name displayed in the address bar.
+storageAccess2.message = A wnewch chi ganiatáu i %1$S i dracio eich gweithgaredd pori ar %2$S?
+
+# LOCALIZATION NOTE (storageAccess3.message, storageAccess.hintText):
+# %1$S and %3$S are both the name of the site URL (www.site1.example) trying to track the user's activity.
+# %2$S is the name of the site URL (www.site2.example) that the user is visiting.  This is the same domain name displayed in the address bar.
+storageAccess3.message = A wnewch chi ganiatáu i %1$S ddefnyddio cwcis a data gwefan ar %2$S? Gall caniatáu hyn adael i %3$S dracio'r hyn rydych chi'n ei wneud ar y wefan hon.
+storageAccess.hintText = Dylech rwystro mynediad os nad ydych yn ymddiried yn neu'n adnabod %1$S.
+
+
+
+confirmationHint.sendToDevice.label = Anfonwyd!
+confirmationHint.copyURL.label = Copïwyd i'r clipfwrdd!
+confirmationHint.pageBookmarked.label = Cadwyd i'r Llyfrgell!
+confirmationHint.addSearchEngine.label = Ychwanegwyd peiriant chwilio!
+confirmationHint.pinTab.label = Piniwyd!
+confirmationHint.pinTab.description = Rhowch glic de i'r tab i'w ddabinio.
+confirmationHint.passwordSaved.label = Cyfrinair wedi'i gadw!
+confirmationHint.loginRemoved.label = Mewngofnodi wedi'i dynnu!
+confirmationHint.breakageReport.label = Anfonwyd yr adroddiad. Diolch!
+
+# LOCALIZATION NOTE (livebookmarkMigration.title):
+# Used by the export of user's live bookmarks to an OPML file as a title for the file.
+# %S will be replaced with brandShortName
+livebookmarkMigration.title                      = Nodau Tudalen Byw %S
+
+# LOCALIZATION NOTE (gnomeSearchProviderSearch):
+# Used for search by Gnome Shell activity screen, %S is a searched string.
+gnomeSearchProviderSearch=Chwiliwch ar y we am %S
diff --git a/l10n-cy/browser/chrome/browser/customizableui/customizableWidgets.properties b/l10n-cy/browser/chrome/browser/customizableui/customizableWidgets.properties
new file mode 100644
index 0000000000..ba6b6f548b
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/customizableui/customizableWidgets.properties
@@ -0,0 +1,100 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+history-panelmenu.label = Hanes
+# LOCALIZATION NOTE(history-panelmenu.tooltiptext2): %S is the keyboard shortcut
+history-panelmenu.tooltiptext2 = Dangos eich hanes (%S)
+
+remotetabs-panelmenu.label = Tabiau wedi'u Cydweddu
+remotetabs-panelmenu.tooltiptext2 = Dangos tabiau o ddyfeisiau eraill
+
+privatebrowsing-button.label = Ffenestr Breifat
+# LOCALIZATION NOTE(privatebrowsing-button.tooltiptext): %S is the keyboard shortcut
+privatebrowsing-button.tooltiptext = Agor ffenestr Pori Preifat newydd (%S)
+
+save-page-button.label = Cadw Tudalen
+# LOCALIZATION NOTE(save-page-button.tooltiptext3): %S is the keyboard shortcut
+save-page-button.tooltiptext3 = Cadw'r dudalen hon (%S)
+
+find-button.label = Canfod
+# LOCALIZATION NOTE(find-button.tooltiptext3): %S is the keyboard shortcut.
+find-button.tooltiptext3 = Canfod ar y dudalen (%S)
+
+open-file-button.label = Agor Ffeil
+# LOCALIZATION NOTE (open-file-button.tooltiptext3): %S is the keyboard shortcut.
+open-file-button.tooltiptext3 = Agor ffeil (%S)
+
+developer-button.label = Datblygwr
+# LOCALIZATION NOTE(developer-button.tooltiptext): %S is the keyboard shortcut
+developer-button.tooltiptext2 = Agor offer datblygwyr Gwe (%S)
+
+profiler-button.label = Proffiliwr
+profiler-button.tooltiptext = Cofnodi proffil perfformiad
+
+sidebar-button.label = Barrau Ochr
+sidebar-button.tooltiptext2 = Dangos barau ochr
+
+add-ons-button.label = Ychwanegion
+# LOCALIZATION NOTE(add-ons-button.tooltiptext3): %S is the keyboard shortcut
+add-ons-button.tooltiptext3 = Rheoli eich ychwanegion (%S)
+
+preferences-button.label = Dewisiadau
+preferences-button.tooltiptext2 = Agor dewisiadau
+preferences-button.tooltiptext.withshortcut = Agor dewisiadau (%S)
+# LOCALIZATION NOTE (preferences-button.labelWin): Windows-only label for Options
+preferences-button.labelWin = Opsiynau
+# LOCALIZATION NOTE (preferences-button.tooltipWin): Windows-only tooltip for Options
+preferences-button.tooltipWin2 = Agor opsiynau
+
+zoom-controls.label = Offer Chwyddo
+zoom-controls.tooltiptext2 = Offer chwyddo
+
+zoom-out-button.label = Chwyddo allan
+# LOCALIZATION NOTE(zoom-out-button.tooltiptext2): %S is the keyboard shortcut.
+zoom-out-button.tooltiptext2 = Chwyddo allan (%S)
+
+# LOCALIZATION NOTE(zoom-reset-button.tooltiptext2): %S is the keyboard shortcut.
+zoom-reset-button.tooltiptext2 = Ailosod lefel chwyddo (%S)
+
+zoom-in-button.label = Chwyddo mewn
+# LOCALIZATION NOTE(zoom-in-button.tooltiptext2): %S is the keyboard shortcut.
+zoom-in-button.tooltiptext2 = Chwyddo i mewn (%S)
+
+edit-controls.label = Rheolyddion Golygu
+edit-controls.tooltiptext2 = Rheolyddion golygu
+
+cut-button.label = Torri
+# LOCALIZATION NOTE(cut-button.tooltiptext2): %S is the keyboard shortcut.
+cut-button.tooltiptext2 = Torri (%S)
+
+copy-button.label = Copïo
+# LOCALIZATION NOTE(copy-button.tooltiptext2): %S is the keyboard shortcut.
+copy-button.tooltiptext2 = Copïo (%S)
+
+paste-button.label = Gludo
+# LOCALIZATION NOTE(paste-button.tooltiptext2): %S is the keyboard shortcut.
+paste-button.tooltiptext2 = Gludo (%S)
+
+# LOCALIZATION NOTE (characterencoding-button2.label): The \u00ad text at the beginning
+# of the string is used to disable auto hyphenation on the button text when it is displayed
+# in the menu panel.
+characterencoding-button2.label = Amgodiad Testun
+characterencoding-button2.tooltiptext = Dangos opsiynau amgodiad testun
+
+email-link-button.label = E-bostio'r Ddolen
+email-link-button.tooltiptext3 = E-bostio dolen i'r dudalen hon
+
+# LOCALIZATION NOTE(quit-button.tooltiptext.linux2): %1$S is the brand name (e.g. Firefox),
+# %2$S is the keyboard shortcut
+quit-button.tooltiptext.linux2 = Gadael %1$S (%2$S)
+# LOCALIZATION NOTE(quit-button.tooltiptext.mac): %1$S is the brand name (e.g. Firefox),
+# %2$S is the keyboard shortcut
+quit-button.tooltiptext.mac = Gadael %1$S (%2$S)
+
+panic-button.label = Anghofio
+panic-button.tooltiptext = Anghofio am beth hanes pori
+
+toolbarspring.label = Bwlch Hyblyg
+toolbarseparator.label = Gwahanydd
+toolbarspacer.label = Bwlch
diff --git a/l10n-cy/browser/chrome/browser/downloads/downloads.properties b/l10n-cy/browser/chrome/browser/downloads/downloads.properties
new file mode 100644
index 0000000000..1ecb338d6a
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/downloads/downloads.properties
@@ -0,0 +1,99 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (stateStarting):
+# Indicates that the download is starting.
+stateStarting=Cychwyn…
+# LOCALIZATION NOTE (stateFailed):
+# Indicates that the download failed because of an error.
+stateFailed=Methiant
+# LOCALIZATION NOTE (statePaused):
+# Indicates that the download was paused by the user.
+statePaused=Oedi
+# LOCALIZATION NOTE (stateCanceled):
+# Indicates that the download was canceled by the user.
+stateCanceled=Diddymwyd
+# LOCALIZATION NOTE (stateCompleted):
+# Indicates that the download was completed.
+stateCompleted=Cwblhawyd
+# LOCALIZATION NOTE (stateBlockedParentalControls):
+# Indicates that the download was blocked by the Parental Controls feature of
+# Windows.  "Parental Controls" should be consistently named and capitalized
+# with the display of this feature in Windows.  The following article can
+# provide a reference for the translation of "Parental Controls" in various
+# languages:
+# http://windows.microsoft.com/en-US/windows-vista/Set-up-Parental-Controls
+stateBlockedParentalControls=Rhwystrwyd gan Rheolaeth Rhiant
+# LOCALIZATION NOTE (blockedMalware, blockedPotentiallyUnwanted,
+#                    blockedUncommon2):
+# These strings are shown in the panel for some types of blocked downloads. You
+# may need to adjust "downloads.width" in "downloads.dtd" if this turns out to
+# be longer than the other existing status strings.
+blockedMalware=Mae'r ffeil ynn cynnwys firws neu ddrwgwar.
+blockedPotentiallyUnwanted=Gall y ffeil hon niweidio eich cyfrifiadur.
+blockedInsecure = Nid oedd modd llwytho'r ffeil hon i lawr yn ddiogel.
+blockedPotentiallyInsecure=Ffeil heb ei llwytho i lawr: Perygl diogelwch posib.
+blockedUncommon2=Nid yw'r ffeil hon yn cael ei llwytho i lawr yn aml.
+
+# LOCALIZATION NOTE (fileMovedOrMissing):
+# Displayed when a complete download which is not at the original folder.
+fileMovedOrMissing=Ffeil wedi ei symud neu ar goll
+
+# LOCALIZATION NOTE (unblockHeaderUnblock, unblockHeaderOpen,
+#                    unblockTypeMalware, unblockTypePotentiallyUnwanted2,
+#                    unblockTypeUncommon2, unblockTip2, unblockButtonOpen,
+#                    unblockButtonUnblock, unblockButtonConfirmBlock, unblockInsecure):
+# These strings are displayed in the dialog shown when the user asks a blocked
+# download to be unblocked.  The severity of the threat is expressed in
+# descending order by the unblockType strings, it is higher for files detected
+# as malware and lower for uncommon downloads.
+unblockHeaderUnblock=Ydych chi'n siŵr eich bod eisiau caniatáu'r llwytho i lawr?
+unblockHeaderOpen=Ydych chi'n siŵr eich bod eisiau agor y ffeil hon?
+unblockTypeMalware=Mae'r ffeil yn cynnwys firws neu ddrwgwar arall fydd yn gwneud drwg i'ch cyfrifiadur.
+unblockTypePotentiallyUnwanted2=Gall y ffeil hon, sydd wedi ei ffugio i edrych fel rhaglen cynorthwyol, wneud newidiadau annisgwyl i'ch rhaglenni a'ch gosodiadau.
+unblockTypeUncommon2=Nid yw'r ffeil hon yn cael ei llwytho i lawr yn aml ac nad yw'n ddiogel ei hagor. Gall fod yn cynnwys firws neu wneud newidiadau annisgwyl i' ch rhaglenni a'ch gosodiadau.
+unblockInsecure=Mae'r ffeil yn defnyddio cysylltiad anniogel. Efallai y bydd yn llwgr neu wedi cael ymyrraeth yn ystod y broses llwytho i lawr.
+unblockTip2=Gallwch chwilio am ffynhonnell llwytho i lawr arall neu geisio llwytho'r ffeil i lawr rhywbryd eto.
+unblockButtonOpen=Agor
+unblockButtonUnblock=Caniatáu'r llwytho i lawr
+unblockButtonConfirmBlock=Tynnu ffeil
+
+# LOCALIZATION NOTE (sizeWithUnits):
+# %1$S is replaced with the size number, and %2$S with the measurement unit.
+sizeWithUnits=%1$S %2$S
+sizeUnknown=Maint anhysbys
+
+# LOCALIZATION NOTE (statusSeparator, statusSeparatorBeforeNumber):
+# These strings define templates for the separation of different elements in the
+# status line of a download item.  As a separator, by default we use the Unicode
+# character U+2014 'EM DASH' (long dash).  Examples of status lines include
+# "Canceled - 222.net", "1.1 MB - website2.com", or "Paused -  1.1 MB".  Note
+# that we use a wider space after the separator when it is followed by a number,
+# just to avoid visually confusing it with with a minus sign with some fonts.
+# If you use a different separator, this might not be necessary.  However, there
+# is usually no need to change the separator or the order of the substitutions,
+# even for right-to-left languages, unless the defaults are not suitable.
+statusSeparator=%1$S %2$S
+statusSeparatorBeforeNumber=%1$S —  %2$S
+
+# LOCALIZATION NOTE (otherDownloads3):
+# This is displayed in an item at the bottom of the Downloads Panel when
+# there are more downloads than can fit in the list in the panel. Use a
+# semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/Localization_and_Plurals
+otherDownloads3=Dim ffeiliau yn llwytho i lawr;%1$S ffeil yn llwytho i lawr;%1$S ffeil yn llwytho i lawr;%1$S ffeil yn llwytho i lawr;%1$S ffeil yn llwytho i lawr;%1$S ffeil yn llwytho i lawr
+
+# LOCALIZATION NOTE (showLabel, showMacLabel):
+# This is displayed when you hover a download item in the Library widget view.
+# showMacLabel is only shown on Mac OSX.
+showLabel=Agor y Ffolder Cynnwys
+showMacLabel=Agor yn y Chwilotwr
+# LOCALIZATION NOTE (openFileLabel):
+# Displayed when hovering a complete download, indicates that it's possible to
+# open the file using an app available in the system.
+openFileLabel=Agor Ffeil
+# LOCALIZATION NOTE (retryLabel):
+# Displayed when hovering a download which is able to be retried by users,
+# indicates that it's possible to download this file again.
+retryLabel=Ceisio Llwytho i Lawr Eto
diff --git a/l10n-cy/browser/chrome/browser/feeds/subscribe.properties b/l10n-cy/browser/chrome/browser/feeds/subscribe.properties
new file mode 100644
index 0000000000..dc9b3fc4dd
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/feeds/subscribe.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (addProtocolHandlerMessage):
+# Message displayed when adding a protocol handler:
+# %1$S is the application's domain, %2$S is the type of protocol
+addProtocolHandlerMessage=Ychwanegu “%1$S” fel rhaglen ar gyfer dolenni %2$S?
+addProtocolHandlerAddButton=Ychwanegu Rhaglen
+addProtocolHandlerAddButtonAccesskey=Y
diff --git a/l10n-cy/browser/chrome/browser/fxmonitor.properties b/l10n-cy/browser/chrome/browser/fxmonitor.properties
new file mode 100644
index 0000000000..fdd8de9fe6
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/fxmonitor.properties
@@ -0,0 +1,49 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Header of the popup
+fxmonitor.popupHeader=Oes gennych chi gyfrif i'r wefan hon?
+# Firefox Monitor must be treated as a brand, and kept in English.
+# It cannot be:
+# - Declined to adapt to grammatical case.
+# - Transliterated.
+# - Translated.
+fxmonitor.brandName=Firefox Monitor
+# Tooltip text for the popup's anchor icon in the URL bar
+# %S is replaced with fxmonitor.brandName.
+fxmonitor.anchorIcon.tooltiptext=Gwefan wedi ei hadrodd i %S
+# Text content of popup. Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This version is only used when the number of accounts is smaller than 100,000.
+# The placeholders are:
+# #1: The exact number of accounts compromised in the breach.
+# #2: The name of the breached site.
+# #3: The year of the breach.
+# #4: The brand name ("Firefox Monitor").
+fxmonitor.popupText=#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;#1 cyfrif gyda #2 wedi eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.
+# Text content of popup. Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This version is only used when the number of accounts is greater than 100,000.
+# The placeholders are:
+# #1: The number of accounts compromised in the breach, rounded down to the
+#     most significant digit.
+#     Ex.: 234,567 -> More than 200,000 accounts [...]
+#          345,678,901 -> More than 300,000,000 accounts [...]
+#          4,567,890,123 -> More than 4,000,000,000 accounts [...]
+# #2: The name of the breached site.
+# #3: The year of the breach.
+# #4: The brand name ("Firefox Monitor").
+fxmonitor.popupTextRounded=Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.;Cafodd mwy na #1 cyfrif #2 eu cyfaddawdu yn #3. Gwiriwch #4 i weld os yw eich un chi o dan fygythiad.
+# %S is replaced with fxmonitor.brandName.
+fxmonitor.checkButton.label=Gwirio %S
+fxmonitor.checkButton.accessKey=G
+fxmonitor.dismissButton.label=Cau
+fxmonitor.dismissButton.accessKey=C
+# %S is replaced with fxmonitor.brandName.
+fxmonitor.neverShowButton.label=Peidio dangos rhybuddion %S
+fxmonitor.neverShowButton.accessKey=P
diff --git a/l10n-cy/browser/chrome/browser/migration/migration.dtd b/l10n-cy/browser/chrome/browser/migration/migration.dtd
new file mode 100644
index 0000000000..758aec018e
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/migration/migration.dtd
@@ -0,0 +1,53 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+
+<!ENTITY migrationWizard.title          "Dewin Mewnforio">
+
+<!ENTITY importFrom.label               "Mewnforio Dewisiadau, Nodau Tudalen, Hanes, Cyfrineiriau, a data arall o:">
+<!ENTITY importFromUnix.label           "Mewnforio Dewisiadau, Nodau Tudalen, Hanes, Cyfrineiriau a data arall o:">
+
+<!ENTITY importFromIE.label             "Microsoft Internet Explorer">
+<!ENTITY importFromIE.accesskey         "M">
+<!ENTITY importFromEdge.label           "Microsoft Edge">
+<!ENTITY importFromEdge.accesskey       "E">
+<!ENTITY importFromEdgeLegacy.label     "Yr Hen Microsoft Edge">
+<!ENTITY importFromEdgeLegacy.accesskey "H">
+<!ENTITY importFromEdgeBeta.label       "Microsoft Edge Beta">
+<!ENTITY importFromEdgeBeta.accesskey   "d">
+<!ENTITY importFromNothing.label        "Peidio mewnforio dim">
+<!ENTITY importFromNothing.accesskey    "d">
+<!ENTITY importFromSafari.label         "Safari">
+<!ENTITY importFromSafari.accesskey     "S">
+<!ENTITY importFromCanary.label         "Chrome Canary">
+<!ENTITY importFromCanary.accesskey     "n">
+<!ENTITY importFromChrome.label         "Chrome">
+<!ENTITY importFromChrome.accesskey     "C">
+<!ENTITY importFromChromeBeta.label     "Chrome Beta">
+<!ENTITY importFromChromeBeta.accesskey "B">
+<!ENTITY importFromChromeDev.label      "Chrome Dev">
+<!ENTITY importFromChromeDev.accesskey  "D">
+<!ENTITY importFromChromium.label       "Chromium">
+<!ENTITY importFromChromium.accesskey   "u">
+<!ENTITY importFromFirefox.label        "Firefox">
+<!ENTITY importFromFirefox.accesskey    "x">
+<!ENTITY importFrom360se.label          "360 Porwr Diogel">
+<!ENTITY importFrom360se.accesskey      "3">
+
+<!ENTITY noMigrationSources.label       "Methu canfod unrhyw rhaglenni sy'n cynnwys nodau tudalen, hanes na data cyfrineiriau.">
+
+<!ENTITY importSource.title             "Gosodiadau Mewnforio a Data">
+<!ENTITY importItems.title              "Eitemau i'w Mewnforio">
+<!ENTITY importItems.label              "Dewis eitemau i'w mewnforio:">
+
+<!ENTITY migrating.title                "Mewnforio…">
+<!ENTITY migrating.label                "Mae'r eitemau canlynol yn cael eu mewnforio…">
+
+<!ENTITY selectProfile.title            "Dewis Proffil">
+<!ENTITY selectProfile.label            "Mae'r proffiliau canlynol ar gael i'w mewnforio o:">
+
+<!ENTITY done.title                     "Wedi Cwblhau Mewnforio">
+<!ENTITY done.label                     "Cafodd yr eitemau canlynol eu mewnforio'n llwyddiannus:">
+
+<!ENTITY closeSourceBrowser.label       "Gwnewch yn siŵr fod y porwr wedi ei gau cyn parhau.">
diff --git a/l10n-cy/browser/chrome/browser/migration/migration.properties b/l10n-cy/browser/chrome/browser/migration/migration.properties
new file mode 100644
index 0000000000..8c0b5efada
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/migration/migration.properties
@@ -0,0 +1,76 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+profileName_format=%S %S
+
+# Browser Specific
+sourceNameIE=Internet Explorer
+sourceNameEdge=Microsoft Edge
+sourceNameEdgeBeta=Microsoft Edge Beta
+sourceNameSafari=Safari
+sourceNameCanary=Google Chrome Canary
+sourceNameChrome=Google Chrome
+sourceNameChromeBeta=Google Chrome Beta
+sourceNameChromeDev=Google Chrome Dev
+sourceNameChromium=Chromium
+sourceNameFirefox=Mozilla Firefox
+sourceName360se=360 Porwr Diogel
+
+importedBookmarksFolder=O %S
+
+importedSafariReadingList=Rhestr Darllen (O Safari)
+importedEdgeReadingList=Rhestr Darllen (O Edge)
+
+# Import Sources
+# Note: When adding an import source for profile reset, add the string name to
+# resetProfile.js if it should be listed in the reset dialog.
+1_ie=Dewisiadau Rhyngrwyd
+1_edge=Gosodiadau
+1_safari=Dewisiadau
+1_chrome=Dewisiadau
+1_360se=Dewisiadau
+
+2_ie=Cwcis
+2_edge=Cwcis
+2_safari=Cwcis
+2_chrome=Cwcis
+2_firefox=Cwcis
+2_360se=Cwcis
+
+4_ie=Hanes Pori
+4_edge=Hanes Pori
+4_safari=Hanes Pori
+4_chrome=Hanes Pori
+4_firefox_history_and_bookmarks=Hanes Pori a Nodau Tudalen
+4_360se=Hanes Pori
+
+8_ie=Hanes Ffurflenni a Gadwyd
+8_edge=Hanes Ffurflenni a Gadwyd
+8_safari=Hanes Ffurflenni a Gadwyd
+8_chrome=Hanes Ffurflenni a Gadwyd
+8_firefox=Hanes Ffurflenni a Gadwyd
+8_360se=Hanes Ffurflenni a Gadwyd
+
+16_ie=Cadw Cyfrineiriau
+16_edge=Cadw Cyfrineiriau
+16_safari=Cadw Cyfrineiriau
+16_chrome=Cadw Cyfrineiriau
+16_firefox=Cadw Cyfrineiriau
+16_360se=Cadw Cyfrineiriau
+
+32_ie=Ffefrynnau
+32_edge=Ffefrynnau
+32_safari=Nodau Tudalen
+32_chrome=Nodau Tudalen
+32_360se=Nodau Tudalen
+
+64_ie=Data Arall
+64_edge=Data Arall
+64_safari=Data Arall
+64_chrome=Data Arall
+64_firefox_other=Data Arall
+64_360se=Data Arall
+
+128_firefox=Ffenestri a Thabiau
+
diff --git a/l10n-cy/browser/chrome/browser/newInstall.dtd b/l10n-cy/browser/chrome/browser/newInstall.dtd
new file mode 100644
index 0000000000..66e5e4d460
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/newInstall.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE: For this feature, "installation" is used to mean "this
+ discrete download of Firefox" and "version" is used to mean "the specific
+ revision number of a given Firefox channel". These terms are not synonymous.
+-->
+
+<!ENTITY window.title "Newyddion Pwysig">
+<!ENTITY window.style "width: 490px">
+<!ENTITY sync "I gydweddu gwybodaeth rydych chi eisoes wedi'i gadw i Firefox gyda'r gosodiad hwn o &brandShortName;, mewngofnodwch gyda'ch &syncBrand.fxAccount.label;.">
+<!ENTITY continue-button "Parhau">
+
+<!ENTITY mainText "Mae gan y gosodiad hwn o &brandShortName; broffil newydd. Nid yw'n rhannu nodau tudalen, cyfrineiriau a dewisiadau defnyddwyr gyda gosodiadau eraill o Firefox (gan gynnwys Firefox, Firefox ESR, Firefox Beta, Firefox Developer Edition, a Firefox Nightly) ar y cyfrifiadur hwn.">
diff --git a/l10n-cy/browser/chrome/browser/places/bookmarkProperties.properties b/l10n-cy/browser/chrome/browser/places/bookmarkProperties.properties
new file mode 100644
index 0000000000..a5a6c1675e
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/places/bookmarkProperties.properties
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+dialogAcceptLabelAddItem=Ychwanegu
+dialogAcceptLabelSaveItem=Cadw
+dialogAcceptLabelAddMulti=Ychwanegu Nodau Tudalen
+dialogAcceptLabelEdit=Cadw
+dialogTitleAddBookmark=Nod Tudalen Newydd
+dialogTitleAddFolder=Ffolder Newydd
+dialogTitleAddMulti=Nodau Tudalen Newydd
+dialogTitleEdit=Priodweddau "%S"
+
+bookmarkAllTabsDefault=[Enw Ffolder]
+newFolderDefault=Ffolder Newydd
+newBookmarkDefault=Nod Tudalen Newydd
diff --git a/l10n-cy/browser/chrome/browser/places/places.dtd b/l10n-cy/browser/chrome/browser/places/places.dtd
new file mode 100644
index 0000000000..22d8cbb9bb
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/places/places.dtd
@@ -0,0 +1,63 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE (places.library.title): use "Library", "Archive" or "Repository" -->
+<!ENTITY places.library.title  "Llyfrgell">
+<!ENTITY places.library.width  "700">
+<!ENTITY places.library.height "500">
+<!ENTITY organize.label        "Trefnu">
+<!ENTITY organize.accesskey    "T">
+<!ENTITY organize.tooltip      "Trefnu eich nodau tudalen">
+
+<!ENTITY file.close.label               "Cau">
+<!ENTITY file.close.accesskey           "C">
+<!ENTITY cmd.close.key                  "w">
+<!ENTITY views.label                    "Golygon">
+<!ENTITY views.accesskey                "G">
+<!ENTITY views.tooltip                  "Newid eich golwg">
+<!ENTITY view.columns.label             "Dangos Colofnau">
+<!ENTITY view.columns.accesskey         "D">
+<!ENTITY view.sort.label                "Trefnu">
+<!ENTITY view.sort.accesskey            "r">
+<!ENTITY view.unsorted.label            "Didrefn">
+<!ENTITY view.unsorted.accesskey        "i">
+<!ENTITY view.sortAscending.label       "Trefnu A > Z">
+<!ENTITY view.sortAscending.accesskey   "A">
+<!ENTITY view.sortDescending.label      "Trefnu Z > A">
+<!ENTITY view.sortDescending.accesskey  "Z">
+
+<!ENTITY importBookmarksFromHTML.label     "Mewnforio Nodau Tudalen o HTML…">
+<!ENTITY importBookmarksFromHTML.accesskey "i">
+<!ENTITY exportBookmarksToHTML.label       "Allforio Nodau Tudalen i HTML…">
+<!ENTITY exportBookmarksToHTML.accesskey   "H">
+<!ENTITY importOtherBrowser.label          "Mewnforio Data o Borwr Arall…">
+<!ENTITY importOtherBrowser.accesskey      "A">
+
+<!ENTITY cmd.backup.label               "Wrth Gefn…">
+<!ENTITY cmd.backup.accesskey           "W">
+<!ENTITY cmd.restore2.label             "Adfer">
+<!ENTITY cmd.restore2.accesskey         "A">
+<!ENTITY cmd.restoreFromFile.label      "Dewis Ffeil…">
+<!ENTITY cmd.restoreFromFile.accesskey  "D">
+
+<!ENTITY col.name.label          "Enw">
+<!ENTITY col.tags.label          "Tagiau">
+<!ENTITY col.url.label           "Lleoliad">
+<!ENTITY col.mostrecentvisit.label "Ymweliad Diweddaraf">
+<!ENTITY col.visitcount.label    "Cyfrif Ymweliadau">
+<!ENTITY col.dateadded.label     "Ychwanegwyd">
+<!ENTITY col.lastmodified.label  "Newidwyd Ddiwethaf">
+
+<!ENTITY cmd.find.key  "f">
+
+<!ENTITY maintenance.label      "Mewnforio ac Allforio">
+<!ENTITY maintenance.accesskey  "M">
+<!ENTITY maintenance.tooltip    "Mewnforio a chadw eich nodau tudalen wrth gefn">
+
+<!ENTITY backButton.tooltip  "Mynd nôl">
+
+<!ENTITY forwardButton.tooltip  "Mynd ymlaen">
+
+<!ENTITY detailsPane.selectAnItemText.description "Dewis eitem i'w gweld a golygu ei phriodweddau">
+
diff --git a/l10n-cy/browser/chrome/browser/places/places.properties b/l10n-cy/browser/chrome/browser/places/places.properties
new file mode 100644
index 0000000000..8a0e0be60a
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/places/places.properties
@@ -0,0 +1,75 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+load-js-data-url-error=Am resymau diogelwch, ni fydd modd gosod javascript na urlau data o'r ffenestr hanes na bar ochr.
+noTitle=(dim teitl)
+
+bookmarksMenuEmptyFolder=(Gwag)
+
+bookmarksBackupTitle=Enw ffeil nodau tudalen wrth gefn
+
+bookmarksRestoreAlertTitle=Adfer i'r Nodau Tudalen
+bookmarksRestoreAlert=Bydd hwn yn newid eich holl nodau tudalen presennol drwy'r copïo wrth gefn. Iawn?
+bookmarksRestoreTitle=Dewis nodau tudalen wrth gefn
+bookmarksRestoreFilterName=JSON
+
+bookmarksRestoreFormatError=Math ffeil nad yw'n cael ei chynnal.
+bookmarksRestoreParseError=Methu prosesu'r ffeil wrth gefn.
+
+# LOCALIZATION NOTE (view.sortBy.1.name.label): sortBy properties are versioned.
+# When any of these changes, all of the properties must be bumped, and the
+# change must be annotated here.  Both label and accesskey must be updated.
+# - version 1: changed view.sortBy.1.date.
+view.sortBy.1.name.label=Trefnu yn ôl Enw
+view.sortBy.1.name.accesskey=E
+view.sortBy.1.url.label=Trefnu yn ôl Lleoliad
+view.sortBy.1.url.accesskey=L
+view.sortBy.1.date.label=Trefnu yn ôl yr Ymweliad Diweddaraf
+view.sortBy.1.date.accesskey=Y
+view.sortBy.1.visitCount.label=Trefnu yn ôl Cyfrif Ymweliadau
+view.sortBy.1.visitCount.accesskey=C
+view.sortBy.1.dateAdded.label=Trefnu yn ôl Ychwanegwyd
+view.sortBy.1.dateAdded.accesskey=Y
+view.sortBy.1.lastModified.label=Trefnu yn ôl Newid Diwethaf
+view.sortBy.1.lastModified.accesskey=N
+view.sortBy.1.tags.label=Trefnu yn ôl Tagiau
+view.sortBy.1.tags.accesskey=T
+
+searchBookmarks=Chwilio'r Nodau Tudalen
+searchHistory=Hanes Chwilio
+searchDownloads=Chwilio'r Llwytho i Lawr
+
+SelectImport=Mewnforio Ffeil Nodau Tudalen
+EnterExport=Allforio Ffeil Nodau Tudalen
+
+detailsPane.noItems=Dim eitemau
+# LOCALIZATION NOTE (detailsPane.itemsCountLabel): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of items
+# example: 111 items
+detailsPane.itemsCountLabel=Dim eitemau;#1eitem;#1eitem;#1eitem;#1eitem;#1eitem
+
+
+# LOCALIZATION NOTE (lockPrompt.text)
+# %S will be replaced with the application name.
+lockPrompt.title=Gwall Cychwyn Porwr
+lockPrompt.text=Ni fydd y system nodau tudalen a hanes yn weithredol gan fod un o ffeiliau %S yn cael ei defnyddio gan raglen arall. Mae rhai meddalwedd diogelwch yn gallu achosi'r broblem yma.
+lockPromptInfoButton.label=Dysgu Rhagor
+lockPromptInfoButton.accessKey=D
+
+# LOCALIZATION NOTE (cmd.deleteSinglePage.accesskey,
+# cmd.deleteMultiplePages.accesskey): these accesskeys can use the same
+# character, since they're never displayed at the same time
+cmd.deleteSinglePage.label=Dileu Tudalen
+cmd.deleteSinglePage.accesskey=D
+cmd.deleteMultiplePages.label=Dileu Tudalennau
+cmd.deleteMultiplePages.accesskey=D
+
+# LOCALIZATION NOTE (cmd.bookmarkSinglePage.accesskey,
+# cmd.bookmarkMultiplePages.accesskey): these accesskeys can use the same
+# character, since they're never displayed at the same time
+cmd.bookmarkSinglePage.label=Gosod Nod i Dudalen
+cmd.bookmarkSinglePage.accesskey=G
+cmd.bookmarkMultiplePages.label=Gosod Nodau i Dudalennau
+cmd.bookmarkMultiplePages.accesskey=N
diff --git a/l10n-cy/browser/chrome/browser/pocket.properties b/l10n-cy/browser/chrome/browser/pocket.properties
new file mode 100644
index 0000000000..18b55f5d51
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/pocket.properties
@@ -0,0 +1,30 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addtags = Ychwanegu Tagiau
+alreadyhaveacct = Eisoes yn ddefnyddiwr Pocket?
+errorgeneric = Bu gwall wrth geisio cadw i Pocket.
+learnmore = Dysgu Rhagor
+loginnow = Mewngofnodi
+maxtaglength = Mae tagiau wedi eu cyfyngu i 25 nod
+onlylinkssaved = Dim ond dolenni y mae modd eu cadw
+pagenotsaved = Heb Gadw'r Dudalen
+pageremoved = Tudalen wedi ei Thynnu
+pagesaved = Cadwyd i Pocket
+processingremove = Tynnu Tudalen…
+processingtags = Ychwanegu tagiau…
+removepage = Tynnu Tudalen
+save = Cadw
+saving = Cadw…
+signupemail = Ymunwch drwy e-bost
+signuptosave = Ymunwch â Pocket. Mae am ddim.
+suggestedtags = Awgrymiadau o Dagiau
+tagline = Cadw erthyglau a fideos o Firefox i'w gweld yn Pocket ar unrhyw ddyfais, ar unrhyw adeg.
+taglinestory_one = Cliciwch Fotwm Pocket i gadw unrhyw erthygl, fideo neu dudalen o Firefox.
+taglinestory_two = Gweld yn Pocket ar unrhyw ddyfais, ar unrhyw adeg.
+tagssaved = Ychwanegwyd Tagiau
+tos = Drwy barhau, rydych yn cytuno i <a href="%1$S" target="_blank">Delerau Gwasanaeth</a> a <a href="%2$S" target="_blank">Pholisi Preifatrwydd</a> Pocket
+tryitnow = Rhowch Gynnig Arno
+signupfirefox = Ymuno drwy Firefox
+viewlist = Gweld Rhestr
diff --git a/l10n-cy/browser/chrome/browser/safebrowsing/safebrowsing.properties b/l10n-cy/browser/chrome/browser/safebrowsing/safebrowsing.properties
new file mode 100644
index 0000000000..da985334dd
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/safebrowsing/safebrowsing.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+errorReportFalseDeceptiveTitle=Nid yw hon yn wefan twyllodrus
+errorReportFalseDeceptiveMessage=Nid yw'n bosib adrodd ar y gwall hwn ar hyn o bryd.
diff --git a/l10n-cy/browser/chrome/browser/search.properties b/l10n-cy/browser/chrome/browser/search.properties
new file mode 100644
index 0000000000..7d835fdcab
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/search.properties
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+searchtip=Chwilio gan ddefnyddio %S
+
+# LOCALIZATION NOTE (searchHeader): this is displayed at the top of the panel
+# showing search suggestions.
+# %S is replaced with the name of the current default search engine.
+searchHeader=Chwilio gyda %S
+
+# LOCALIZATION NOTE (cmd_pasteAndSearch): "Search" is a verb, this is the
+# search bar equivalent to the url bar's "Paste & Go"
+cmd_pasteAndSearch=Gludo a Chwilio
+
+cmd_clearHistory=Clirio Hanes Chwilio
+cmd_clearHistory_accesskey=H
+
+# LOCALIZATION NOTE (cmd_addFoundEngine): %S is replaced by the name of
+# a search engine offered by a web page. Each engine is displayed as a
+# menuitem at the bottom of the search panel.
+cmd_addFoundEngine=Ychwanegu "%S"
+# LOCALIZATION NOTE (cmd_addFoundEngineMenu): When more than 5 engines
+# are offered by a web page, instead of listing all of them in the
+# search panel using the cmd_addFoundEngine string, they will be
+# grouped in a submenu using cmd_addFoundEngineMenu as a label.
+cmd_addFoundEngineMenu=Ychwanegu peiriant chwilio
+
+searchAddFoundEngine2=Ychwanegu Peiriant Chwilio
+
+# LOCALIZATION NOTE (searchForSomethingWith2):
+# This string is used to build the header above the list of one-click
+# search providers:  "Search for <user-typed string> with:"
+searchForSomethingWith2=Chwilio am %S gyda:
+
+# LOCALIZATION NOTE (searchWithHeader):
+# The wording of this string should be as close as possible to
+# searchForSomethingWith2. This string will be used when the user
+# has not typed anything.
+searchWithHeader=Chwilio gyda:
+
+# LOCALIZATION NOTE (searchSettings):
+# This is the label for the button that opens Search preferences.
+searchSettings=Gosodiadau Chwilio
+
diff --git a/l10n-cy/browser/chrome/browser/shellservice.properties b/l10n-cy/browser/chrome/browser/shellservice.properties
new file mode 100644
index 0000000000..388fe58a26
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/shellservice.properties
@@ -0,0 +1,28 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (setDefaultBrowserMessage2, setDefaultBrowserConfirm.label):
+# %S will be replaced by brandShortName
+setDefaultBrowserMessage2          = Cael y gorau o %S drwy ei osod fel eich porwr rhagosodedig
+setDefaultBrowserConfirm.label     = Defnyddio %S fel fy mhorwr rhagosodedig
+setDefaultBrowserConfirm.accesskey = D
+setDefaultBrowserOptions.label     = Dewisiadau
+setDefaultBrowserOptions.accesskey = D
+setDefaultBrowserNotNow.label      = Nid nawr
+setDefaultBrowserNotNow.accesskey  = N
+setDefaultBrowserNever.label       = Peidiwch gofyn i mi eto
+setDefaultBrowserNever.accesskey   = P
+
+# LOCALIZATION NOTE (setDefaultBrowserTitle, setDefaultBrowserMessage, setDefaultBrowserDontAsk, setDefaultBrowserAlertConfirm.label, setDefaultBrowserAlertNotNow.label):
+# These strings are used as an alternative to the ones above, in a modal dialog.
+# %S will be replaced by brandShortName
+setDefaultBrowserTitle=Porwr Rhagosodedig
+setDefaultBrowserMessage=Nid %S yw eich porwr rhagosodedig. Hoffech chi ei osod fel eich porwr arferol?
+setDefaultBrowserDontAsk=Gwiriwch bob tro wrth gychwyn %S.
+setDefaultBrowserAlertConfirm.label=Defnyddio %S fel fy mhorwr rhagosodedig
+setDefaultBrowserAlertNotNow.label=Nid nawr
+
+desktopBackgroundLeafNameWin=Desktop Background.bmp
+DesktopBackgroundDownloading=Cadw Darlun…
+DesktopBackgroundSet=Gosod Cefndir Bwrdd Gwaith
diff --git a/l10n-cy/browser/chrome/browser/siteData.properties b/l10n-cy/browser/chrome/browser/siteData.properties
new file mode 100644
index 0000000000..c1fb96ebad
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/siteData.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+clearSiteDataPromptTitle=Clirio'r holl gwcis a data gwefan
+# LOCALIZATION NOTE (clearSiteDataPromptText): %S = brandShortName
+clearSiteDataPromptText=Bydd dewis ‘Clirio Nawr’ yn clirio'r holl gwcis a data gwefan wedi ei storio gan %S. Gall hyn eich allgofnodi o wefannau a thynnu cynnwys all-lein.
+clearSiteDataNow=Clirio Nawr
diff --git a/l10n-cy/browser/chrome/browser/sitePermissions.properties b/l10n-cy/browser/chrome/browser/sitePermissions.properties
new file mode 100644
index 0000000000..9e77e7a2fd
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/sitePermissions.properties
@@ -0,0 +1,53 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (state.current.allowed,
+#                    state.current.allowedForSession,
+#                    state.current.allowedTemporarily,
+#                    state.current.blockedTemporarily,
+#                    state.current.blocked,
+#                    state.current.hide):
+# This label is used to display active permission states in the site
+# identity popup (which does not have a lot of screen space).
+state.current.allowed = Caniatáu
+state.current.allowedForSession = Caniatáu ar gyfer y Sesiwn
+state.current.allowedTemporarily = Caniatáu Dros Dro
+state.current.blockedTemporarily = Rhwystro Dros Dro
+state.current.blocked = Wedi ei Rwystro
+state.current.prompt = Gofyn Bob Tro
+
+# LOCALIZATION NOTE (state.multichoice.alwaysAsk,
+#                    state.multichoice.allow,
+#                    state.multichoice.allowForSession,
+#                    state.multichoice.block):
+# Used to label permission state checkboxes in the page info dialog.
+state.multichoice.alwaysAsk = Gofyn Bob Tro
+state.multichoice.allow = Caniatáu
+state.multichoice.allowForSession = Caniatáu ar gyfer y Sesiwn
+state.multichoice.block = Rhwystro
+
+state.multichoice.autoplayblock = Rhwystro Sain
+state.multichoice.autoplayblockall = Rhwystro Sain a Fideo
+state.multichoice.autoplayallow = Caniatáu Sain a Fideo
+
+permission.autoplay.label = Awtochwarae
+permission.cookie.label = Gosod Cwcis
+permission.desktop-notification3.label = Anfon Hysbysiadau
+permission.camera.label = Defnyddio'r Camera
+permission.microphone.label = Defnyddio'r Meicroffon
+permission.screen.label = Rhannu'r Sgrin
+permission.install.label = Gosod Ychwanegion
+permission.popup.label = Agor Llamlenni
+permission.geo.label = Mynediad i'ch Lleoliad
+permission.xr.label = Cael Mynediad i Ddyfeisiau Rhithrealaeth
+permission.shortcuts.label = Gwrthwneud Llwybrau Byr Bysellfwrdd
+permission.focus-tab-by-prompt.label = Newid i'r Tab hwn
+permission.persistent-storage.label = Cadw Data mewn Storfa Barhaus
+permission.canvas.label = Tynnu Data Canvas
+permission.midi.label = Mynediad i ddyfeisiau MIDI
+permission.midi-sysex.label = Mynediad i ddyfeisiau MIDI sydd â Chefnogaeth SysEx
+permission.https-only-load-insecure.label = Defnyddio HTTP anniogel
+# LOCALIZATION NOTE (permission.open-protocol-handler.label):
+# Open as a verb. "This site may open applications".
+permission.open-protocol-handler.label = Agor rhaglenni
diff --git a/l10n-cy/browser/chrome/browser/syncBrand.dtd b/l10n-cy/browser/chrome/browser/syncBrand.dtd
new file mode 100644
index 0000000000..435934f326
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/syncBrand.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY syncBrand.shortName.label  "Sync">
+<!ENTITY syncBrand.fxAccount.label  "Cyfrif Firefox">
diff --git a/l10n-cy/browser/chrome/browser/syncSetup.properties b/l10n-cy/browser/chrome/browser/syncSetup.properties
new file mode 100644
index 0000000000..9674785b75
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/syncSetup.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Several other strings are used (via Weave.Status.login), but they come from
+#  /services/sync
+
+# Firefox Accounts based setup.
+continue.label = Ymlaen
+
+relinkVerify.title = Rhybudd Cyfuno
+relinkVerify.heading = Ydych chi'n siŵr eich bod am fewngofnodi i Sync?
+# LOCALIZATION NOTE (relinkVerify.description): Email address of a user previously signed into sync.
+relinkVerify.description = Roedd defnyddiwr gwahanol ar y cyfrifiadur yma wedi ei fewngofnodi i Sync. Bydd mewngofnodi yn uno nodau tudalen, cyfrineiriau a gosodiadau eraill gyda %S
diff --git a/l10n-cy/browser/chrome/browser/tabbrowser.properties b/l10n-cy/browser/chrome/browser/tabbrowser.properties
new file mode 100644
index 0000000000..0822b1c8bc
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/tabbrowser.properties
@@ -0,0 +1,128 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+tabs.emptyTabTitle=Tab Newydd
+tabs.emptyPrivateTabTitle=Pori Preifat
+tabs.closeTab=Cau Tab
+tabs.close=Cau
+tabs.closeTitleTabs=Cau tabiau?
+tabs.closeAndQuitTitleTabs=Gadael a chau tabiau?
+tabs.closeAndQuitTitleTabsWin=Gadael a chau tabiau?
+# LOCALIZATION NOTE (tabs.closeWarningMultiple):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The singular form is not considered since this string is used only for
+# multiple tabs.
+tabs.closeWarningMultiple=Rydych ar fin cau #1 tab. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 tab. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 dab. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 thab. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 thab. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 tab. Ydych chi'n siŵr eich bod am barhau?
+# LOCALIZATION NOTE (tabs.closeWarningMultipleSessionRestore2):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The forms for 0 or 1 items are not considered since this string is used only
+# for multiple tabs.
+# If
+#   "Tabs in non-private windows will be restored when you restart"
+# is difficult to translate, you could translate
+#   "Tabs (except those in private windows) will be restored when you restart"
+# instead.
+tabs.closeWarningMultipleSessionRestore2=;Rydych ar fin cau tabiau #1. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch yn ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau tabiau #1. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch yn ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau tabiau #1. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch yn ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau tabiau #1. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch yn ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau tabiau #1. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch yn ailgychwyn. Ydych chi'n siŵr eich bod am barhau?
+tabs.closeButtonMultiple=Cau tabiau
+tabs.closeWarningPromptMe=Rhybuddio pan fyddai'n cau tabiau niferus
+
+# LOCALIZATION NOTE (tabs.closeWarningMultipleWindows):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The forms for 0 or 1 items are not considered since this string is used only for
+# multiple windows. The %S replacement form will be replaced with the contents
+# of tabs.closeWarningMultipleWindowsTabSnippet, which will contain the number
+# of tabs in these windows.
+# Note that every one of these plural forms must contain one instance of '%S'.
+tabs.closeWarningMultipleWindows=Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestr %S. Ydych chi'n siŵr eich bod am barhau?
+# LOCALIZATION NOTE (tabs.closeWarningMultipleWindowsSessionRestore2):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The forms for 0 or 1 items are not considered since this string is used only for
+# multiple windows. The %S replacement form will be replaced with the contents
+# of tabs.closeWarningMultipleWindowsTabSnippet, which will contain the number
+# of tabs in these windows.
+# If
+#   "Tabs in non-private windows will be restored when you restart"
+# is difficult to translate, you could translate
+#   "Tabs (except those in private windows) will be restored when you restart"
+# instead.
+# Note that every one of these plural forms must contain one instance of '%S'.
+tabs.closeWarningMultipleWindowsSessionRestore2=;Rydych ar fin cau #1 ffenestri %S. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch chi'n ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestri %S. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch chi'n ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestri %S. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch chi'n ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;Rydych ar fin cau #1 ffenestri %S. Bydd tabiau mewn ffenestri nad ydynt yn breifat yn cael eu hadfer pan fyddwch chi'n ailgychwyn. Ydych chi'n siŵr eich bod am barhau?;nad ydynt yn breifat yn cael eu hadfer pan fyddwch chi'n ailgychwyn. Ydych chi'n siŵr eich bod am barhau?
+
+# LOCALIZATION NOTE (tabs.closeWarningMultipleWindowsTabSnippet):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# The singular form is not considered since this string is used only for
+# multiple windows which must contain multiple tabs (in total).
+# This string will be inserted in tabs.closeWarningMultipleWindows
+tabs.closeWarningMultipleWindowsTabSnippet=gyda #1 tab;gyda #1 tab;gyda #1 tab;gyda #1 tab;gyda #1 tab;gyda #1 tab
+
+# LOCALIZATION NOTE (tabs.closeTabs.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs that will be closed. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.closeTabs.tooltip=Cau tab;Cau #1 tab;Cau #1 dab;Cau #1 tab;Cau #1 tab;Cau #1 tab
+
+# LOCALIZATION NOTE (tabs.muteAudio2.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# %S is the keyboard shortcut for "Mute tab".
+# #1 is the number of tabs that will be muted. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.muteAudio2.tooltip=Tewi tab (%S);Tewi #1 tab (%S);Tewi #1 tab (%S);Tewi #1 tab (%S);Tewi #1 tab (%S);Tewi #1 tab (%S)
+
+# LOCALIZATION NOTE (tabs.unmuteAudio2.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# %S is the keyboard shortcut for "Unmute tab".
+# #1 is the number of tabs that will be unmuted. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.unmuteAudio2.tooltip=Dad-dewi tab (%S);Dad-dewi #1 tab (%S);Dad-dewi #1 tab (%S);Dad-dewi #1 tab (%S);Dad-dewi #1 tab (%S);Dad-dewi #1 tab (%S)
+
+# LOCALIZATION NOTE (tabs.muteAudio2.background.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs that will be muted. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.muteAudio2.background.tooltip=Tewi tab;Tewi #1 tab;Tewi #1 tab;Tewi #1 tab;Tewi #1 tab;Tewi #1 tab
+
+# LOCALIZATION NOTE (tabs.unmuteAudio2.background.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs that will be unmuted. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.unmuteAudio2.background.tooltip=Dad-dewi tab;Dad-dewi #1 tab;Dad-dewi #1 tab;Dad-dewi #1 tab;Dad-dewi #1 tab;Dad-dewi #1 tab
+
+# LOCALIZATION NOTE (tabs.unblockAudio2.tooltip):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of tabs that will have their audio unblocked. This is ignored for the
+# single tab case in English, but can be used by other locales as necessary.
+tabs.unblockAudio2.tooltip=Chwarae tab;Chwarae #1 tab;Chwarae #1 tab;Chwarae #1 tab;Chwarae #1 tab;Chwarae #1 tab
+
+# LOCALIZATION NOTE (tabs.allowTabFocusByPromptForSite):
+# %S is the hostname of the site where dialogs are allowed to switch tabs
+tabs.allowTabFocusByPromptForSite=Caniatáu i ddeialogau o %S eich cymryd i'w tabiau
+
+# LOCALIZATION NOTE (tabs.containers.tooltip):
+# Displayed as a tooltip on container tabs
+# %1$S is the title of the current tab
+# %2$S is the name of the current container
+tabs.containers.tooltip=%1$S - %2$S
+
+# LOCALIZATION NOTE (tabs.openWarningTitle, tabs.openWarningMultipleBranded, tabs.openButtonMultiple, tabs.openWarningPromptMeBranded):
+# These items are moved from chrome/browser/places/places.properties
+# Now they are not specific to bookmark.
+tabs.openWarningTitle=Cadarnhau ar agor
+tabs.openWarningMultipleBranded=Rydych ar fin agor %S tab.  Gall hyn arafu %S tra fo'r tudalennau'n llwytho.  Ydych chi'n siŵr eich bod am barhau?
+tabs.openButtonMultiple=Agor tabiau
+tabs.openWarningPromptMeBranded=Rhybuddio y gall agor tabiau niferus arafu %S
+
+browsewithcaret.checkMsg=Peidio dangos y blwch deialog yma eto.
+browsewithcaret.checkWindowTitle=Pori Caret
+browsewithcaret.checkLabel=Mae pwyso F7 yn cychwyn a diffodd Pori Caret. Mae'r nodwedd hon yn gosod cyrchwr symudol ar dudalennau gwe, gan ganiatáu i chi ddewis testun gyda'r bysellfwrdd. Hoffech chi gychwyn Pori Caret?
diff --git a/l10n-cy/browser/chrome/browser/taskbar.properties b/l10n-cy/browser/chrome/browser/taskbar.properties
new file mode 100644
index 0000000000..6070acce07
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/taskbar.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+taskbar.tasks.newTab.label=Agor tab newydd
+taskbar.tasks.newTab.description=Agor tab porwr newydd.
+taskbar.tasks.newWindow.label=Agor ffenestr newydd
+taskbar.tasks.newWindow.description=Agor ffenestr porwr newydd.
+taskbar.tasks.newPrivateWindow.label=Ffenestr breifat newydd
+taskbar.tasks.newPrivateWindow.description=Agor ffenestr newydd yn y modd preifat.
+taskbar.frequent.label=Aml
+taskbar.recent.label=Diweddar
diff --git a/l10n-cy/browser/chrome/browser/translation.dtd b/l10n-cy/browser/chrome/browser/translation.dtd
new file mode 100644
index 0000000000..2bcd759b48
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/translation.dtd
@@ -0,0 +1,72 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (translation.thisPageIsIn.label,
+  -                     translation.translateThisPage.label):
+  -  These 2 strings are used to construct a sentence that contains a dropdown
+  -  showing the detected language of the current web page.
+  -  In en-US it looks like this:
+  -    This page is in [detected language] Translate this page?
+  -  "detected language" here is a language name coming from the
+  -  global/languageNames.properties file; for some locales it may not be in
+  -  the correct grammar case to keep the same structure of the original
+  -  sentence. -->
+
+<!ENTITY translation.thisPageIsIn.label         "Mae'r dudalen yn">
+<!ENTITY translation.translateThisPage.label    "Cyfieithu'r dudalen?">
+<!ENTITY translation.translate.button           "Cyfieithu">
+<!ENTITY translation.notNow.button              "Nid Nawr">
+
+<!ENTITY translation.translatingContent.label   "Cyfieithu cynnwys y dudalen…">
+<!-- LOCALIZATION NOTE (translation.translatedFrom.label,
+  -                     translation.translatedTo.label,
+  -                     translation.translatedToSuffix.label):
+  -  These 3 strings are used to construct a sentence that contains 2 dropdowns
+  -  showing the source and target language of a translated web page.
+  -  In en-US it looks like this:
+  -    This page has been translated from [from language] to [to language]
+  -  "from language" and "to language" here are language names coming from the
+  -  global/languageNames.properties file; for some locales they may not be in
+  -  the correct grammar case to keep the same structure of the original
+  -  sentence.
+  -
+  -  translation.translatedToSuffix.label (empty in en-US) is for locales that
+  -  need to display some text after the second drop down for the sentence to
+  -  be grammatically correct. -->
+
+<!ENTITY translation.translatedFrom.label       "Mae'r dudalen wedi ei chyfieithu o'r">
+<!ENTITY translation.translatedTo.label         "at">
+<!ENTITY translation.translatedToSuffix.label   "">
+
+<!ENTITY translation.showOriginal.button        "Dangos y Gwreiddiol">
+<!ENTITY translation.showTranslation.button     "Dangos y Cyfieithiad">
+
+<!ENTITY translation.errorTranslating.label     "Bu gwall wrth gyfieithu'r dudalen hon.">
+<!ENTITY translation.tryAgain.button            "Ceisio Eto">
+
+<!ENTITY translation.serviceUnavailable.label   "Nid yw cyfieithu ar gael ar hyn o bryd. Ceisiwch eto.">
+
+<!ENTITY translation.options.menu               "Dewisiadau">
+<!-- LOCALIZATION NOTE (translation.options.neverForSite.accesskey,
+  -                     translation.options.preferences.accesskey):
+  -  The accesskey values used here should not clash with the value used for
+  -  translation.options.neverForLanguage.accesskey in translation.properties
+  -->
+<!ENTITY translation.options.neverForSite.label "Peidio byth cyfieithu'r wefan hon">
+<!ENTITY translation.options.neverForSite.accesskey "b">
+<!ENTITY translation.options.preferences.label  "Dewisiadau cyfieithu">
+<!ENTITY translation.options.preferences.accesskey "D">
+<!-- LOCALIZATION NOTE (translation.options.attribution.beforeLogo,
+  -                     translation.options.attribution.afterLogo):
+  -  These 2 strings are displayed before and after a 'Microsoft Translator'
+  -  logo.
+  -->
+
+<!-- LOCALIZATION NOTE (translation.options.attribution.poweredByYandex,
+                        translation.options.attribution.beforeLogo,
+  -                     translation.options.attribution.afterLogo):
+  -  translation.options.attribution.poweredByYandex is displayed instead of
+  -  the other two strings when yandex translation engine is preferred by the
+  -  user.
+  -->
+
diff --git a/l10n-cy/browser/chrome/browser/translation.properties b/l10n-cy/browser/chrome/browser/translation.properties
new file mode 100644
index 0000000000..928a0994dc
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/translation.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (translation.options.neverForLanguage.label):
+#  %S is a language name coming from the global/languageNames.properties file.
+translation.options.neverForLanguage.label=Peidio cyfieithu %S
+
+# LOCALIZATION NOTE (translation.options.neverForLanguage.accesskey):
+# The accesskey value used here should not clash with the values used for
+# translation.options.*.accesskey in translation.dtd
+translation.options.neverForLanguage.accesskey=P
diff --git a/l10n-cy/browser/chrome/browser/uiDensity.properties b/l10n-cy/browser/chrome/browser/uiDensity.properties
new file mode 100644
index 0000000000..07330a3771
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/uiDensity.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+uiDensity.menuitem-touch.acceltext=Galluogwyd y Modd Tabled
diff --git a/l10n-cy/browser/chrome/browser/webrtcIndicator.properties b/l10n-cy/browser/chrome/browser/webrtcIndicator.properties
new file mode 100644
index 0000000000..269e6411ab
--- /dev/null
+++ b/l10n-cy/browser/chrome/browser/webrtcIndicator.properties
@@ -0,0 +1,61 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE : FILE This file contains the webrtc global indicator strings
+
+# LOCALIZATION NOTE (webrtcIndicator.windowtitle): %S is the brand name (e.g. Firefox).
+# This string is used so that the window has a title in tools that enumerate/look for window
+# titles. It is not normally visible anywhere.
+webrtcIndicator.windowtitle = %S - Dangosydd Rhannu
+
+webrtcIndicator.sharingCameraAndMicrophone.tooltip = Mae eich camera a'ch meicroffon yn cael eu rhannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingCamera.tooltip              = Mae eich camera'n cael ei rannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingMicrophone.tooltip          = Mae eich meicroffon yn cael ei rannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingApplication.tooltip = Mae rhaglen yn ei rannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingScreen.tooltip = Mae eich sgrin yn cael ei rannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingWindow.tooltip = Mae ffenestr yn cael ei rannu. Cliciwch i reoli'r rhannu.
+webrtcIndicator.sharingBrowser.tooltip = Mae tab yn cael ei rannu. Cliciwch i reoli'r rhannu.
+
+
+# LOCALIZATION NOTE : The following strings are only used on Mac for
+# menus attached to icons near the clock on the mac menubar.
+
+# LOCALIZATION NOTE (webrtcIndicator.sharing*With.menuitem):
+# %S is the title of the tab using the share.
+webrtcIndicator.sharingCameraWith.menuitem = Rhannu camera gyda "%S"
+webrtcIndicator.sharingMicrophoneWith.menuitem = Rhannu Meicroffon gyda "%S"
+webrtcIndicator.sharingApplicationWith.menuitem = Rhannu Rhaglen gyda "%S"
+webrtcIndicator.sharingScreenWith.menuitem = Rhannu Sgrin gyda "%S"
+webrtcIndicator.sharingWindowWith.menuitem = Rhannu Ffenestr gyda "%S"
+webrtcIndicator.sharingBrowserWith.menuitem = Rhannu Tab gyda "%S"
+webrtcIndicator.controlSharing.menuitem = Rhannu Rheoli
+# LOCALIZATION NOTE (webrtcIndicator.sharingCameraWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+webrtcIndicator.sharingCameraWithNTabs.menuitem = Peidio rhannu Camera gyda thabiau;Rhannu Camera gyda #1 tab;Rhannu Camera gyda #1 dab;Rhannu Camera gyda #1 thab;Rhannu Camera gyda #1 thab;Rhannu Camera gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.sharingMicrophoneWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+webrtcIndicator.sharingMicrophoneWithNTabs.menuitem = Peidio rhannu Meicroffon gyda thabiau;Rhannu Meicroffon gydag #1 tab;Rhannu Meicroffon gyda #1 dab;Rhannu Meicroffon gyda #1 thab;Rhannu Meicroffon gyda #1 thab;Rhannu Meicroffon gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.sharingApplicationWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+webrtcIndicator.sharingApplicationWithNTabs.menuitem = Peidio rhannu Rhaglen gyda thabiau;Rhannu Rhaglen gyda #1 tab;Rhannu Rhaglen gyda #1 dab;Rhannu Rhaglen gyda #1 thab;Rhannu Rhaglen gyda #1 thab;Rhannu Rhaglen gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.sharingScreenWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+webrtcIndicator.sharingScreenWithNTabs.menuitem = Peidio rhannu'r Sgrin gyda thabiau;Rhannu'r Sgrin gyda #1 tab;Rhannu'r Sgrin gyda #1 dab;Rhannu'r Sgrin gyda #1 thab;Rhannu'r Sgrin gyda #1 thab;Rhannu'r Sgrin gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.sharingWindowWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+webrtcIndicator.sharingWindowWithNTabs.menuitem = Peidio rhannu Ffenestr gyda thabiau;Rhannu Ffenestr gydag #1 tab;Rhannu Ffenestr gyda #1 dab;Rhannu Ffenestr gyda #1 thab;Rhannu Ffenestr gyda #1 thab;Rhannu Ffenestr gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.sharingBrowserWithNTabs.menuitem):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This message is shown when the contents of a tab is shared during a WebRTC
+# session, which currently is only possible with Loop/Hello.
+webrtcIndicator.sharingBrowserWithNTabs.menuitem = Peidio rhannu Tab gyda thabiau;Rhannu Tab gydag #1 tab;Rhannu Tab gyda #1 dab;Rhannu Tab gyda #1 thab;Rhannu Tab gyda #1 thab;Rhannu Tab gyda #1 tab
+# LOCALIZATION NOTE (webrtcIndicator.controlSharingOn.menuitem):
+# %S is the title of the tab using the share.
+webrtcIndicator.controlSharingOn.menuitem = Rheoli Rhannu gyda "%S"
diff --git a/l10n-cy/browser/chrome/overrides/appstrings.properties b/l10n-cy/browser/chrome/overrides/appstrings.properties
new file mode 100644
index 0000000000..4aee0bf9e9
--- /dev/null
+++ b/l10n-cy/browser/chrome/overrides/appstrings.properties
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+malformedURI2=Gwiriwch fod yr URL yn gywir a cheisiwch eto.
+fileNotFound=Nid yw Firefox yn gallu canfod y ffeil yn %S.
+fileAccessDenied=Nid yw ffeil %S yn ddarllenadwy.
+dnsNotFound2=Nid oedd modd cysylltu â'r gweinydd yn %S.
+unknownProtocolFound=Nid yw Firefox yn gwybod sut i agor y cyfeiriad hwn, gan fod un o'r protocolau canlynol (%S) heb eu cysylltu ag unrhyw raglen neu nid yw'n cael ei ganiatáu yn y cyd-destun hwn.
+connectionFailure=Nid yw Firefox yn gallu cysylltu â'r gweinydd yn %S.
+netInterrupt=Cafodd cysylltiad â %S ei darfu wrth i'r dudalen lwytho.
+netTimeout=Mae'r gweinydd yn %S yn cymryd gormod o amser i ymateb.
+redirectLoop=Mae Firefox wedi canfod fod gweinydd yn ailgyfeirio'r cais am y cyfeiriad yma mewn ffordd na fydd yn cael ei gwblhau.
+## LOCALIZATION NOTE (confirmRepostPrompt): In this item, don’t translate "%S"
+confirmRepostPrompt=I ddangos y dudalen hon, rhaid i %S anfon gwybodaeth fydd yn ailadrodd unrhyw weithred (megis chwilio neu gadarnhau gorchymyn) gafodd ei chyflawni ynghynt.
+resendButton.label=Ail anfon
+unknownSocketType=Nid yw Firefox yn gwybod sut i gyfathrebu gyda'r gweinydd.
+netReset=Cafodd y cysylltiad i'r gweinydd ei ailosod wrth i'r dudalen lwytho.
+notCached=Nid yw'r ddogfen ar gael bellach.
+netOffline=Mae Firefox yn y modd all-lein ar hyn o bryd ac yn methu pori.
+isprinting=Nid oes modd i'r ddogfen newid wrth Argraffu neu yn Rhagolwg Argraffu.
+deniedPortAccess=Mae'r cyfeiriad yn defnyddio porth rhwydwaith sy'n cael ei ddefnyddio fel arfer i ddibenion heblaw pori'r We. Mae Firefox wedi gwrthod y cais er eich lles.
+proxyResolveFailure=Mae Firefox wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy nad oes modd ei ganfod.
+proxyConnectFailure=Mae Firefox wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy sy'n gwrthod cysylltiadau.
+contentEncodingError=Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am ei bod yn defnyddio math o gywasgiad nad yw'n cael ei gynnal.
+unsafeContentType=Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am ei bod yn cynnwys math o ffeil gall fod nad yw'n ddiogel ei hagor. Cysylltwch â pherchennog y wefan i'w hysbysu o'r broblem.
+externalProtocolTitle=Cais Protocol Allanol
+externalProtocolPrompt=Rhaid cychwyn rhaglen allanol i drin dolenni %1$S: .\n\n\nCais dolen:\n\n%2$S\n\nRhaglen: %3$S\n\n\nOs nad oeddech yn disgwyl y cais hwn gall fod yn ymgais i gymryd mantais o wendid yn y rhaglen honno. Diddymwch y cais oni bai eich bod yn siŵr nad yw'n faleisus.\n
+#LOCALIZATION NOTE (externalProtocolUnknown): The following string is shown if the application name can't be determined
+externalProtocolUnknown=<Anhysbys>
+externalProtocolChkMsg=Cofio'r dewis ar gyfer y pob dolen o'r math yma.
+externalProtocolLaunchBtn=Cychwyn rhaglen
+malwareBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+harmfulBlocked=Mae'r wefan yn %S yn hysbys fel gwefan niweidiol ac wedi cael ei rhwystro ar sail eich dewisiadau diogelwch.
+unwantedBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+deceptiveBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan twyllodrus ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+cspBlocked=Mae gan y dudalen bolisi diogelwch cynnwys sy'n ei hatal rhag cael ei llwytho yn y ffordd yma.
+xfoBlocked=Mae gan y dudalen hon bolisi X-Frame-Options sy'n ei hatal rhag cael ei lwytho yn y cyd-destun hwn.
+corruptedContentErrorv2=Mae'r wefan %S wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
+remoteXUL=Mae'r dudalen hon yn defnyddio technoleg sydd ddim yn cael ei gynnal bellach gan Firefox.
+## LOCALIZATION NOTE (sslv3Used) - Do not translate "%S".
+sslv3Used=Nid yw Firefox yn gallu gwarantu diogelwch eich data ar %S gan ei fod yn defnyddio SSLv3, protocol diogelwch sydd wedi torri.
+inadequateSecurityError=Mae'r wefan wedi ceisio negydu lefel annigonol o ddiogelwch.
+blockedByPolicy=Mae eich sefydliad wedi rhwystro mynediad i'r dudalen hon neu'r wefan.
+networkProtocolError=Mae'r wefan Firefox wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
diff --git a/l10n-cy/browser/chrome/overrides/netError.dtd b/l10n-cy/browser/chrome/overrides/netError.dtd
new file mode 100644
index 0000000000..98a1b0bbb3
--- /dev/null
+++ b/l10n-cy/browser/chrome/overrides/netError.dtd
@@ -0,0 +1,135 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
+%brandDTD;
+
+<!ENTITY loadError.label "Anhawster llwytho tudalen">
+<!ENTITY retry.label "Ceisiwch eto">
+<!ENTITY returnToPreviousPage.label "Ewch Nôl">
+<!ENTITY returnToPreviousPage1.label "Ewch Nôl (Argymell)">
+<!ENTITY advanced2.label "Uwch…">
+<!ENTITY viewCertificate.label "Darllen Tystysgrif">
+
+<!-- Specific error messages -->
+
+<!ENTITY connectionFailure.longDesc "&sharedLongDesc;">
+
+<!ENTITY deniedPortAccess.longDesc "">
+
+<!ENTITY dnsNotFound.pageTitle "Heb Ganfod Gweinydd">
+<!ENTITY dnsNotFound.longDesc1 "
+<strong>Os yw'r cyfeiriad yna'n gywir, dyma dri pheth i chi roi cynnig arnyn nhw</strong>
+<ul>
+  <li>Ceisiwch eto'n hwyrach.</li>
+  <li>Gwiriwch eich cysylltiad rhwydwaith.</li>
+  <li>Os ydych wedi eich cysylltu ond y tu nôl i fur cadarn, gwiriwch fod gan &brandShortName; ganiatâd i gael mynediad i'r We.</li>
+</ul>
+">
+
+<!ENTITY fileNotFound.longDesc "<ul> <li>Gwiriwch yr enw ffeil am brif lythrennu neu wallau teipio eraill.</li> <li>Gwiriwch i weld os yw'r ffeil wedi symud, ailenwi neu ei dileu.</li> </ul>">
+
+<!ENTITY fileAccessDenied.longDesc "<ul> <li>Gall ei fod wedi ei dynnu, symud neu fod caniatâd ffeiliau yn rhwystro mynediad.</li> </ul>">
+
+<!ENTITY generic.longDesc "<p>Nid yw &brandShortName; yn gallu llwytho'r dudalen am ryw reswm.</p>">
+
+<!ENTITY captivePortal.title "Mewngofnodi i'r rhwydwaith">
+<!ENTITY captivePortal.longDesc2 "<p>Rhaid i chi fewngofnodi i'r rhwydwaith hwn cyn i chi gael mynediad i'r Rhyngrwyd.</p>">
+
+<!ENTITY openPortalLoginPage.label2 "Agor Tudalen Mewngofnodi i'r Rhwydwaith">
+
+<!ENTITY malformedURI.pageTitle "URL annilys">
+
+<!ENTITY netInterrupt.longDesc "&sharedLongDesc;">
+
+<!ENTITY notCached.longDesc "<p>Nid yw'r ddogfen gofynnwyd amdani ar gael yn storfa dros dro &brandShortName;.</p><ul><li>Fel cam i sicrhau diogelwch nid yw &brandShortName; yn gofyn eto am ddogfennau sensitif.</li><li>Cliciwch Ceisio Eto i ofyn eto am y ddogfen o'r wefan.</li></ul>">
+
+<!ENTITY netOffline.longDesc2 "<ul> <li>Clicio &quot;Ceisio newid eto&quot; i newid i&apos;r modd ar-lein ac ail lwytho'r dudalen.</li> </ul>">
+
+<!ENTITY contentEncodingError.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY unsafeContentType.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY netReset.longDesc "&sharedLongDesc;">
+
+<!ENTITY netTimeout.longDesc "&sharedLongDesc;">
+
+<!ENTITY unknownProtocolFound.longDesc "<ul> <li>Efallai bydd angen i chi osod meddalwedd arall i agor y cyfeiriad yma.</li> </ul>">
+
+<!ENTITY proxyConnectFailure.longDesc "<ul> <li>Gwiriwch osodiadau'r dirprwy i wneud yn siŵr eu bod yn gywir.</li> <li>Cysylltwch â'ch gweinyddwr system i wneud yn siŵr fod y gweinydd dirprwyol yn gweithio.</li> </ul>">
+
+<!ENTITY proxyResolveFailure.longDesc "<ul> <li>Gwiriwch y gosodiadau dirprwyol i wneud yn siŵr eu bod yn gywir.</li> <li>Gwiriwch fod gan eich cyfrifiadur cyswllt a'r we sy'n gweithio.</li> <li>Os yw eich cyfrifiadur wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan &brandShortName; fynediad i'r we.</li> </ul>">
+
+<!ENTITY redirectLoop.longDesc "<ul> <li>Gall y broblem yma fod wedi ei hachosi drwy analluogi neu wrthod cwci.</li> </ul>">
+
+<!ENTITY unknownSocketType.longDesc "<ul> <li>Gwiriwch fod gan eich system Reolwr Diogelwch Personol wedi ei osod.</li> <li>Gall hyn fod oherwydd ffurfweddiad ansafonol ar y gweinydd.</li> </ul>">
+
+<!ENTITY nssFailure2.longDesc2 "<ul> <li>Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am nad oes modd dilysu'r data rydych wedi ei dderbyn.</li> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!-- Localization note (certerror.introPara2) - The text content of the span tag
+will be replaced at runtime with the name of the server to which the user
+was trying to connect. -->
+<!ENTITY certerror.introPara2 "Mae &brandShortName; wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <span class='hostname'/>. Os ewch i'r gwefan yma, gall ymosodwyr geisio dwyn gwybodaeth fel eich cyfrineiriau, e-byst neu fanylion cardiau credyd.">
+<!ENTITY certerror.sts.introPara "Mae &brandShortName; wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <span class='hostname'/> gan fod y wefan angen cysylltiad diogel.">
+
+<!ENTITY certerror.expiredCert.introPara "Mae &brandShortName; wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <span class='hostname'/>. Un ai mae'r wefan wedi ei gam ffurfweddu neu mae cloc eich cyfrifiadur wedi ei osod i'r amser anghywir.">
+<!ENTITY certerror.expiredCert.secondPara2 "Mae'n debyg fod tystysgrif y wefan wedi dod i ben, sy'n atal &brandShortName; rhag cysylltu'n ddiogell. Os ewch chi i'r wefan hon gall ymosodwyr geisio dwy gwybodaeth fel eich cyfrineiriau, e-byst neu fanylion cerdyn credyd.">
+<!ENTITY certerror.expiredCert.sts.secondPara "Mae'n debyg fod tystysgrif y wefan wedi dod i ben, sy'n atal &brandShortName; rhag cysylltu'n ddiogell.">
+
+<!ENTITY certerror.whatCanYouDoAboutItTitle "Beth allwch chi wneud am hyn?">
+
+<!ENTITY certerror.unknownIssuer.whatCanYouDoAboutIt "<p>Mae hyn yn fater i'r wefan a does dim fedrwch chi wneud am y peth.</p>
+<p>Os ydych chi ar rwydwaith corfforaethol neu yn defnyddio meddalwedd gwrth-firws gallwch ofyn i'r timau cefnogi am gymorth. Gallwch hefyd hysbysu gweinyddwr y wefan am y broblem.</p>">
+
+<!ENTITY certerror.expiredCert.whatCanYouDoAboutIt2 "<p>Mae cloc eich cyfrifiadur wedi ei osod i <span id='wrongSystemTime_systemDate2'/>. Gwnewch yn siŵr fod y dyddiad, amser a chylch amser yn gywir yn eich gosodiadau system ac yna adnewyddu <span class='hostname'/>.</p>
+<p>Os yw eich cloc eisoes wedi ei osod i'r amser cywir, mwy na thebyg mae'r wefan wedi ei gam osod a does dim fedrwch chi ei wneud i ddatrys y broblem. Gallwch hysbysu gweinyddwr y wefan am y broblem.</p>">
+
+<!ENTITY certerror.badCertDomain.whatCanYouDoAboutIt "<p>Mae'n fater i'r wefan a does dim fedrwch chi wneud i ddatrys y mater. Gallwch hysbysu gweinyddwr y wefan am y broblem.</p>">
+
+<!ENTITY sharedLongDesc "<ul> <li>Efallai bod y wefan yn brysur neu nad yw ar gael dros dro. Ceisiwch eto ymhen ychydig.</li> <li>Os nad ydych yn gallu llwytho unrhyw dudalennau, gwiriwch gysylltiad rhwydwaith eich cyfrifiadur.</li> <li>Os yw eich cyfrifiadur neu rwydwaith wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan &brandShortName; hawl i fynediad i'r we.</li> </ul>">
+
+<!ENTITY cspBlocked.longDesc "<p>Mae &brandShortName; wedi rhwystro'r dudalen rhag llwytho yn y ffordd yma gan fod gan y dudalen bolisi diogelwch cynnwys sy'n atal hynny.</p>">
+
+<!ENTITY xfoBlocked.longDesc "<p>Mae &brandShortName; wedi atal y dudalen hon rhag llwytho yn y cyd-destun hwn oherwydd bod gan y dudalen bolisi X-Frame-Options sy'n ei gwrthod.</p>">
+
+<!ENTITY corruptedContentErrorv2.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio ei gweld yn sgil canfod gwall trosglwyddo data.</p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY securityOverride.exceptionButton1Label "Derbyn y Bygythiad a Pharhau">
+
+<!ENTITY errorReporting.automatic2 "Mae adroddiadau gwall fel hyn y cynorthwyo Mozilla i adnabod a rhwystro gwefannau maleisus">
+<!ENTITY errorReporting.learnMore "Dysgu rhagor…">
+
+<!ENTITY remoteXUL.longDesc "<p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu am y broblem..</li></ul></p>">
+
+<!-- LOCALIZATION NOTE (sslv3Used.longDesc2) - Do not translate
+     "SSL_ERROR_UNSUPPORTED_VERSION". -->
+<!ENTITY sslv3Used.longDesc2 "Gwybodaeth uwch: SSL_ERROR_UNSUPPORTED_VERSION">
+
+<!ENTITY certerror.pagetitle2  "Rhybudd: Risg Diogelwch Posibl o'ch Blaen">
+<!ENTITY certerror.sts.pagetitle  "Peidiwch cysylltu: Mater Diogelwch Posib">
+<!ENTITY certerror.whatShouldIDo.badStsCertExplanation1 "Mae gan <span class='hostname'></span> bolisi diogelwch o'r enw HTTP Strict Transport Security (HSTS), sy'n golygu mai dim ond yn ddiogel mae modd i &brandShortName; gysylltu. Nid oes modd gosod eithriad er mwyn ymweld â'r wefan.">
+<!ENTITY certerror.copyToClipboard.label "Copïo testun i'r clipfwrdd">
+
+<!-- LOCALIZATION NOTE (inadequateSecurityError.longDesc) - Do not translate
+     "NS_ERROR_NET_INADEQUATE_SECURITY". -->
+<!ENTITY inadequateSecurityError.longDesc "Mae <p><span class='hostname'></span> yn defnyddio technoleg diogelwch sy'n hen ac yn agored i ymosodiad. Gall yr ymosodwr weld manylion am hyn roeddech yn meddwl ei fod yn ddiogel. Mae angen i weinyddwr y wefan drwsio'r gweinydd yn gyntaf cyn bod modd i chi ymweld â' r wefan.</p><p>Cod gwall: NS_ERROR_NET_INADEQUATE_SECURITY</p>">
+
+<!ENTITY blockedByPolicy.title "Tudalen wedi'i Rhwystro">
+
+<!ENTITY certerror.mitm.longDesc "Mae <span class='hostname'></span> mwy na thebyg yn wefan diogel, ond nid oedd modd sefydlu cysylltiad diogel. Achoswyd hyn gan <span class='mitm-name'/>, sy'n un a'i feddalwedd ar eich cyfrifiadur neu rwydwaith.">
+<!ENTITY certerror.mitm.whatCanYouDoAboutIt1 "Os yw eich meddalwedd gwrth-firws yn cynnwys nodwedd sy'n sganio cysylltiadau wedi eu hamgryptio (“web scanning” neu “https scanning”), gallwch analluogu'r nodwedd honno. Os nad yw hynny'n gweithio, gallwch dynnu ac ailosod y feddalwedd gwrth-firws.">
+<!ENTITY certerror.mitm.whatCanYouDoAboutIt2 "Os ydych ar rwydwaith corfforaethol, cysylltwch a'ch adran TG.">
+<!ENTITY certerror.mitm.whatCanYouDoAboutIt3 "Os nad ydych yn gyfarwydd â <span class='mitm-name'/>, yna gall hyn fod yn ymosodiad ac ni ddylech barhau ar y wefan hon.">
+<!ENTITY certerror.mitm.sts.whatCanYouDoAboutIt3 "Os nad ydych yn gyfarwydd â <span class='mitm-name'/>, yna gall hyn fod yn ymosodiad ac nid oes dim y gallwch ei wneud i gael mynediad i'r wefan.">
+
+<!ENTITY clockSkewError.longDesc "Mae eich cyfrifiadur yn meddwl ei bod hi'n <span id='wrongSystemTime_systemDate1'/>, sy'n rhwystro &brandShortName; rhag cysylltu'n ddiogel. I fynd i <span class='hostname'></span>, diweddarwch gloc eich cyfrifiadur yng ngosodiadau eich system i'r dyddiad, amser a chylch amser cyfredol ac yna adnewyddu <span class='hostname'></span>.">
+
+<!ENTITY prefReset.longDesc "Mae'n edrych fel mai eich gosodiadau diogelwch rhwydwaith sy'n achosi hyn. Hoffech chi adfer y gosodiadau rhagosodedig?">
+<!ENTITY prefReset.label "Adfer y gosodiadau rhagosodedig">
+
+<!ENTITY enableTls10.longDesc "Efallai na fydd y wefan hon yn cefnogi protocol TLS 1.2, sef y fersiwn leiafswm ei chefnogi gan &brandShortName;. Efallai y gall galluogi TLS 1.0 a TLS 1.1 ganiatáu i'r cysylltiad hwn lwyddo.">
+<!ENTITY enableTls10.note "Bydd TLS 1.0 a TLS 1.1 yn cael eu hanalluogi yn barhaol mewn fersiynau yn y dyfodol.">
+<!ENTITY enableTls10.label "Galluogi TLS 1.0 a 1.1">
+
+<!ENTITY networkProtocolError.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio'i gweld oherwydd cafwyd gwall yn y protocol rhwydwaith.</p><ul><li>Cysylltwch â pherchenogion y wefan i roi gwybod iddynt am y broblem hon.</li></ul>">
diff --git a/l10n-cy/browser/chrome/overrides/settingsChange.dtd b/l10n-cy/browser/chrome/overrides/settingsChange.dtd
new file mode 100644
index 0000000000..08c6621606
--- /dev/null
+++ b/l10n-cy/browser/chrome/overrides/settingsChange.dtd
@@ -0,0 +1,7 @@
+<!-- -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- -->
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  settingsChangePreferences.label  "Gall gosodiadau gael eu newid gan ddefnyddio tab Rhaglenni yn Dewisiadau &brandShortName;.">
+<!ENTITY  settingsChangeOptions.label      "Gall gosodiadau gael eu newid gan ddefnyddio tab Rhaglenni yn Dewisiadau &brandShortName;.">
diff --git a/l10n-cy/browser/crashreporter/crashreporter-override.ini b/l10n-cy/browser/crashreporter/crashreporter-override.ini
new file mode 100644
index 0000000000..32bd685383
--- /dev/null
+++ b/l10n-cy/browser/crashreporter/crashreporter-override.ini
@@ -0,0 +1,8 @@
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0. If a copy of the MPL was not distributed with this
+; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+; This file is in the UTF-8 encoding
+[Strings]
+; LOCALIZATION NOTE (CrashReporterProductErrorText2): The %s is replaced with a string containing detailed information.
+CrashReporterProductErrorText2=Profodd Firefox anhawster a chwalodd. Byddwn yn ceisio adfer eich tabiau a ffenestri pan fydd yn ailgychwyn.\n\nYn anffodus, nid yw'r adroddwr chwalfa'n gallu cyflwyno adroddiad chwalu.\n\nManylion: %s
+CrashReporterDescriptionText2=Profodd Firefox anhawster a chwalodd. Byddwn yn ceisio adfer eich tabiau a ffenestri pan fydd yn ailgychwyn.\n\nI'n cynorthwyo i ddadansoddi a chywiro'r broblem, anfonwch adroddiad chwalu atom.
diff --git a/l10n-cy/browser/defaultagent/defaultagent_localized.ini b/l10n-cy/browser/defaultagent/defaultagent_localized.ini
new file mode 100644
index 0000000000..166c7f72c5
--- /dev/null
+++ b/l10n-cy/browser/defaultagent/defaultagent_localized.ini
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This file is in the UTF-8 encoding
+[Strings]
+DefaultBrowserAgentTaskDescription=Mae tasgau Asiant Porwr Rhagosodedig yn gwirio pan fydd y rhagosodiad yn newid o %MOZ_APP_DISPLAYNAME% i borwr arall. Os bydd y newid yn digwydd o dan amgylchiadau amheus, bydd yn annog defnyddwyr i newid yn ôl i %MOZ_APP_DISPLAYNAME% ddim mwy na dwywaith. Mae'r dasg hon yn cael ei gosod yn awtomatig gan %MOZ_APP_DISPLAYNAME%, ac mae'n cael ei hailosod pan fydd %MOZ_APP_DISPLAYNAME% yn diweddaru. I analluogi'r dasg hon, diweddarwch y dewis "default-browser-agent.enabled" ar y dudalen about:config neu'r gosodiad polisi menter %MOZ_APP_DISPLAYNAME% "DisableDefaultBrowserAgent".
+
+DefaultBrowserNotificationTitle=Gwnewch %MOZ_APP_DISPLAYNAME% yn eich porwr rhagosodedig
+DefaultBrowserNotificationText=Nid %MOZ_APP_DISPLAYNAME% bellach yn eich porwr rhagosodedig. Ei wneud yn ragosodedig?
+DefaultBrowserNotificationYesButtonText=Iawn
+DefaultBrowserNotificationNoButtonText=Na
diff --git a/l10n-cy/browser/defines.inc b/l10n-cy/browser/defines.inc
new file mode 100644
index 0000000000..adeee3f2e2
--- /dev/null
+++ b/l10n-cy/browser/defines.inc
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#filter emptyLines
+
+#define MOZ_LANGPACK_CREATOR mozilla.org
+
+# If non-English locales wish to credit multiple contributors, uncomment this
+
+# variable definition and use the format specified.
+
+#define MOZ_LANGPACK_CONTRIBUTORS <em:contributor>Rhoslyn Prys</em:contributor> <em:contributor>David Chan</em:contributor> <em:contributor>Dewi B. Jones</em:contributor>
+
+#unfilter emptyLines
diff --git a/l10n-cy/browser/extensions/formautofill/formautofill.properties b/l10n-cy/browser/extensions/formautofill/formautofill.properties
new file mode 100644
index 0000000000..ee6d0b08bf
--- /dev/null
+++ b/l10n-cy/browser/extensions/formautofill/formautofill.properties
@@ -0,0 +1,241 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (saveAddressesMessage): %S is brandShortName. This string is used on the doorhanger to
+# notify users that addresses are saved.
+saveAddressesMessage = Mae %S nawr yn cadw cyfeiriadau fel bod modd i chi lanw ffurflenni'n gynt.
+# LOCALIZATION NOTE (autofillOptionsLink, autofillOptionsLinkOSX): These strings are used in the doorhanger for
+# updating addresses. The link leads users to Form Autofill browser preferences.
+autofillOptionsLink = Opsiynau Awtolanw Ffurflenni
+autofillOptionsLinkOSX = Dewisiadau Awtolanw Ffurflenni
+# LOCALIZATION NOTE (autofillSecurityOptionsLink, autofillSecurityOptionsLinkOSX): These strings are used
+# in the doorhanger for saving credit card info. The link leads users to Form Autofill browser preferences.
+autofillSecurityOptionsLink = Opsiynau Diogelwch ac Awtolanw Ffurflenni
+autofillSecurityOptionsLinkOSX = Dewisiadau Diogelwch ac Awtolanw Ffurflenni
+# LOCALIZATION NOTE (changeAutofillOptions, changeAutofillOptionsOSX): These strings are used on the doorhanger
+# that notifies users that addresses are saved. The button leads users to Form Autofill browser preferences.
+changeAutofillOptions = Newid Opsiynau Awtolanw Ffurflenni
+changeAutofillOptionsOSX = Newid Dewisiadau Awtolanw Ffurflenni
+changeAutofillOptionsAccessKey = O
+# LOCALIZATION NOTE (addressesSyncCheckbox): If Sync is enabled, this checkbox is displayed on the doorhanger
+# shown when saving addresses.
+addressesSyncCheckbox = Rhannu cyfeiriadau gyda dyfeisiau sydd wedi eu cydweddu
+# LOCALIZATION NOTE (creditCardsSyncCheckbox): If Sync is enabled and credit card sync is available,
+# this checkbox is displayed on the doorhanger shown when saving credit card.
+creditCardsSyncCheckbox = Rhannu cardiau credyd gyda dyfeisiau wedi eu cydweddu
+# LOCALIZATION NOTE (updateAddressMessage, updateAddressDescriptionLabel, createAddressLabel, updateAddressLabel):
+# Used on the doorhanger when an address change is detected.
+updateAddressMessage = Hoffech chi ddiweddaru eich cyfeiriad gyda'r wybodaeth newydd hwn?
+updateAddressDescriptionLabel = Cyfeiriad i'w ddiweddaru:
+createAddressLabel = Creu Cyfeiriad Newydd
+createAddressAccessKey = C
+updateAddressLabel = Diweddaru Cyfeiriad
+updateAddressAccessKey = D
+# LOCALIZATION NOTE (saveCreditCardMessage, saveCreditCardDescriptionLabel, saveCreditCardLabel, cancelCreditCardLabel, neverSaveCreditCardLabel):
+# Used on the doorhanger when users submit payment with credit card.
+# LOCALIZATION NOTE (saveCreditCardMessage): %S is brandShortName.
+saveCreditCardMessage = Hoffech chi i %S gadw'r cerdyn credyd hwn? (Ni fydd y cod diogelwch y cael ei gadw)
+saveCreditCardDescriptionLabel = Cerdyn credyd i'w gadw:
+saveCreditCardLabel = Cadw Cerdyn Credyd
+saveCreditCardAccessKey = e
+cancelCreditCardLabel = Peidio â Chadw
+cancelCreditCardAccessKey = D
+neverSaveCreditCardLabel = Peidio Byth a Chadw Cerdyn Credyd
+neverSaveCreditCardAccessKey = P
+# LOCALIZATION NOTE (updateCreditCardMessage, updateCreditCardDescriptionLabel, createCreditCardLabel, updateCreditCardLabel):
+# Used on the doorhanger when an credit card change is detected.
+updateCreditCardMessage = Hoffech chi ddiweddaru eich cerdyn credyd gyda'r manylion newydd?
+updateCreditCardDescriptionLabel = Cerdyn credyd i'e ddiweddaru:
+createCreditCardLabel = Creu Cerdyn Credyd Newydd
+createCreditCardAccessKey = C
+updateCreditCardLabel = Diweddaru Cerdyn Credyd
+updateCreditCardAccessKey = D
+# LOCALIZATION NOTE (openAutofillMessagePanel): Tooltip label for Form Autofill doorhanger icon on address bar.
+openAutofillMessagePanel = Agor panel neges Awtolanw Ffurflenni
+
+# LOCALIZATION NOTE ( (autocompleteFooterOptionShort, autocompleteFooterOptionOSXShort): Used as a label for the button,
+# displayed at the bottom of the dropdown suggestion, to open Form Autofill browser preferences.
+autocompleteFooterOptionShort = Rhagor o Opsiynau
+autocompleteFooterOptionOSXShort = Dewisiadau
+
+# LOCALIZATION NOTE (autocompleteFooterOption2):
+# Used as a label for the button, displayed at the bottom of the dropdown suggestion, to open Form Autofill browser preferences.
+autocompleteFooterOption2 = Dewisiadau Awtolanw Ffurflenni
+# LOCALIZATION NOTE (autocompleteFooterOptionOSX2):
+# Used as a label for the button, displayed at the bottom of the dropdown suggestion, to open Form Autofill browser preferences.
+autocompleteFooterOptionOSX2 = Dewisiadau Awtolanw Ffurflenni
+# LOCALIZATION NOTE (autocompleteFooterOptionShort2):
+# Used as a label for the button, displayed at the bottom of the dropdown suggestion, to open Form Autofill browser preferences.
+# The short version is used for inputs below a certain width (e.g. 150px).
+autocompleteFooterOptionShort2 = Opsiynau Awtolanw Ffurflenni
+# LOCALIZATION NOTE (autocompleteFooterOptionOSXShort2):
+# Used as a label for the button, displayed at the bottom of the dropdown suggestion, to open Form Autofill browser preferences.
+# The short version is used for inputs below a certain width (e.g. 150px).
+autocompleteFooterOptionOSXShort2 = Dewisiadau Awtolanw Ffurflenni
+# LOCALIZATION NOTE (category.address, category.name, category.organization2, category.tel, category.email):
+# Used in autofill drop down suggestion to indicate what other categories Form Autofill will attempt to fill.
+category.address = cyfeiriad
+category.name = enw
+category.organization2 = corff
+category.tel = ffôn
+category.email = e-bost
+# LOCALIZATION NOTE (fieldNameSeparator): This is used as a separator between categories.
+fieldNameSeparator = ,\u0020
+# LOCALIZATION NOTE (phishingWarningMessage, phishingWarningMessage2): The warning
+# text that is displayed for informing users what categories are about to be filled.
+# "%S" will be replaced with a list generated from the pre-defined categories.
+# The text would be e.g. Also autofills organization, phone, email.
+phishingWarningMessage = Hefyd yn awtolanw %S
+phishingWarningMessage2 = Awtolanw %S
+# LOCALIZATION NOTE (insecureFieldWarningDescription): %S is brandShortName. This string is used in drop down
+# suggestion when users try to autofill credit card on an insecure website (without https).
+insecureFieldWarningDescription = Mae %S wedi canfod gwefan anniogel. Mae Awtolanw Ffurflenni wedi ei analluogi dos dro
+# LOCALIZATION NOTE (clearFormBtnLabel2): Label for the button in the dropdown menu that used to clear the populated
+# form.
+clearFormBtnLabel2 = Gwagio'r Ffurflen Awtolanw
+
+autofillHeader = Ffurflenni ac Awtolanw
+# LOCALIZATION NOTE (autofillAddressesCheckbox): Label for the checkbox that enables autofilling addresses.
+autofillAddressesCheckbox = Awtolanw cyfeiriadau
+# LOCALIZATION NOTE (learnMoreLabel): Label for the link that leads users to the Form Autofill SUMO page.
+learnMoreLabel = Dysgu rhagor
+# LOCALIZATION NOTE (savedAddressesBtnLabel): Label for the button that opens a dialog that shows the
+# list of saved addresses.
+savedAddressesBtnLabel = Cyfeiriadau wedi eu Cadw…
+# LOCALIZATION NOTE (autofillCreditCardsCheckbox): Label for the checkbox that enables autofilling credit cards.
+autofillCreditCardsCheckbox = Awtolanw cardiau credyd
+# LOCALIZATION NOTE (savedCreditCardsBtnLabel): Label for the button that opens a dialog that shows the list
+# of saved credit cards.
+savedCreditCardsBtnLabel = Cardiau Credyd wedi eu Cadw…
+
+autofillReauthCheckboxMac = Gofyn i macOS ddilysu cyn awtolanw, gweld, neu olygu cardiau credyd sydd wedi'u storio.
+autofillReauthCheckboxWin = Gofyn i Windows i ddilysu cyn awtolanw, gweld, neu olygu cardiau credyd sydd wedi'u storio.
+autofillReauthCheckboxLin = Gofyn i Linux ddilysu cyn awtolanw, gweld, neu olygu cardiau credyd sydd wedi'u storio.
+
+# LOCALIZATION NOTE (autofillReauthOSDialogMac): This string is
+# preceded by the operating system (macOS) with "Firefox is trying to ", and
+# has a period added to its end. Make sure to test in your locale.
+autofillReauthOSDialogMac = newid y gosodiadau dilysu
+autofillReauthOSDialogWin = I newid y gosodiadau dilysu, rhowch eich manylion mewngofnodi Windows.
+autofillReauthOSDialogLin = I newid y gosodiadau dilysu, rhowch eich manylion mewngofnodi Linux.
+
+# LOCALIZATION NOTE (manageAddressesTitle, manageCreditCardsTitle): The dialog title for the list of addresses or
+# credit cards in browser preferences.
+manageAddressesTitle = Cyfeiriadau wedi eu Cadw
+manageCreditCardsTitle = Cardiau Credyd wedi eu Cadw
+# LOCALIZATION NOTE (addressesListHeader, creditCardsListHeader): The header for the list of addresses or credit cards
+# in browser preferences.
+addressesListHeader = Cyfeiriadau
+creditCardsListHeader = Cardiau Credyd
+removeBtnLabel = Tynnu
+addBtnLabel = Ychwanegu…
+editBtnLabel = Golygu…
+# LOCALIZATION NOTE (manageDialogsWidth): This strings sets the default width for windows used to manage addresses and
+# credit cards.
+manageDialogsWidth = 560px
+
+# LOCALIZATION NOTE (addNewAddressTitle, editAddressTitle): The dialog title for creating or editing addresses
+# in browser preferences.
+addNewAddressTitle = Ychwanegu Cyfeiriad Newydd
+editAddressTitle = Golygu Cyfeiriad
+givenName = Enw Cyntaf
+additionalName = Enw Canol
+familyName = Enw Olaf
+organization2 = Corff
+streetAddress = Cyfeiriad Stryd
+
+## address-level-3 (Sublocality) names
+# LOCALIZATION NOTE (neighborhood): Used in IR, MX
+neighborhood = Cymdogaeth
+# LOCALIZATION NOTE (village_township): Used in MY
+village_township = Pentref eu Dref
+island = Ynys
+# LOCALIZATION NOTE (townland): Used in IE
+townland = Tref
+
+## address-level-2 names
+city = Tref/Dinas
+# LOCALIZATION NOTE (district): Used in HK, SD, SY, TR as Address Level-2
+# and used in KR as Sublocality.
+district = Ardal
+# LOCALIZATION NOTE (post_town): Used in GB, NO, SE
+post_town = Tref post
+# LOCALIZATION NOTE (suburb): Used in AU as Address Level-2
+# and used in ZZ as Sublocality.
+suburb = Maestref
+
+# address-level-1 names
+province = Ardal/Talaith
+state = Sir
+county = Sir
+# LOCALIZATION NOTE (parish): Used in BB, JM
+parish = Plwyf
+# LOCALIZATION NOTE (prefecture): Used in JP
+prefecture = Rhaglawiaeth
+# LOCALIZATION NOTE (area): Used in HK
+area = Ardal
+# LOCALIZATION NOTE (do_si): Used in KR
+do_si = Do/Si
+# LOCALIZATION NOTE (department): Used in NI, CO
+department = Adran
+# LOCALIZATION NOTE (emirate): Used in AE
+emirate = Emirad
+# LOCALIZATION NOTE (oblast): Used in RU and UA
+oblast = Oblast
+
+# LOCALIZATION NOTE (pin, postalCode, zip, eircode): Postal code name types
+# LOCALIZATION NOTE (pin): Used in IN
+pin = Pin
+postalCode = Cod Post
+zip = Cod Zip
+# LOCALIZATION NOTE (eircode): Used in IE
+eircode = Eircode
+
+country = Gwlad neu Ranbarth
+tel = Ffôn
+email = E-bost
+cancelBtnLabel = Diddymu
+saveBtnLabel = Cadw
+countryWarningMessage2 = Dim ond ar gyfer rhai gwledydd y mae Awtolanw Ffurflenni ar gael ar hyn o bryd.
+
+# LOCALIZATION NOTE (addNewCreditCardTitle, editCreditCardTitle): The dialog title for creating or editing
+# credit cards in browser preferences.
+addNewCreditCardTitle = Ychwanegu Cerdyn Credyd Newydd
+editCreditCardTitle = Golygu Cerdyn Credyd
+cardNumber = Rhif y Cerdyn
+invalidCardNumber = Rhowch rif cerdyn dilys
+nameOnCard = Enw ar y Cerdyn
+cardExpiresMonth = Mis Dod i Ben
+cardExpiresYear = Blwyddyn Daw i Ben
+billingAddress = Cyfeiriad Archebion
+cardNetwork = Mathau o Gerdyn
+# LOCALIZATION NOTE (cardCVV): Credit card security code https://en.wikipedia.org/wiki/Card_security_code
+cardCVV = CVV
+
+# LOCALIZATION NOTE: (cardNetwork.*): These are brand names and should only be translated when a locale-specific name for that brand is in common use
+cardNetwork.amex = American Express
+cardNetwork.cartebancaire = Carte Bancaire
+cardNetwork.diners = Diners Club
+cardNetwork.discover = Discover
+cardNetwork.jcb = JCB
+cardNetwork.mastercard = MasterCard
+cardNetwork.mir = MIR
+cardNetwork.unionpay = Union Pay
+cardNetwork.visa = Visa
+
+# LOCALIZATION NOTE (editCreditCardPasswordPrompt.*, useCreditCardPasswordPrompt.*): %S is brandShortName.
+editCreditCardPasswordPrompt.win = Mae %S yn ceisio dangos manylion cerdyn credyd. Cadarnhewch fynediad i'r cyfrif Windows hwn isod.
+editCreditCardPasswordPrompt.macosx = Mae %S yn ceisio dangos manylion cerdyn credyd.
+# LOCALIZATION NOTE (editCreditCardPasswordPrompt.macos): This string is
+# preceded by the operating system (macOS) with "Firefox is trying to ", and
+# has a period added to its end. Make sure to test in your locale.
+editCreditCardPasswordPrompt.macos = dangos manylion cerdyn credyd
+editCreditCardPasswordPrompt.linux = Mae %S yn ceisio dangos manylion cerdyn credyd.
+useCreditCardPasswordPrompt.win = Mae %S yn ceisio dangos manylion cerdyn credyd. Cadarnhewch fynediad i'r cyfrif Windows hwn isod.
+useCreditCardPasswordPrompt.macosx = Mae %S yn ceisio defnyddio manylion cerdyn credyd wedi ei gadw.
+# LOCALIZATION NOTE (useCreditCardPasswordPrompt.macos): This string is
+# preceded by the operating system (macOS) with "Firefox is trying to ", and
+# has a period added to its end. Make sure to test in your locale.
+useCreditCardPasswordPrompt.macos = defnyddio manylion cerdyn credyd wedi'i storio
+useCreditCardPasswordPrompt.linux = Mae %S yn ceisio defnyddio manylion cerdyn credyd wedi ei gadw.
diff --git a/l10n-cy/browser/extensions/report-site-issue/webcompat.properties b/l10n-cy/browser/extensions/report-site-issue/webcompat.properties
new file mode 100644
index 0000000000..048c8e7496
--- /dev/null
+++ b/l10n-cy/browser/extensions/report-site-issue/webcompat.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE(wc-reporter.label2): This string will be used in the
+# Firefox page actions menu. Localized length should be considered.
+wc-reporter.label2=Adrodd ar Fater Gwefan…
+# LOCALIZATION NOTE(wc-reporter.tooltip): A site compatibility issue is
+# a website bug that exists in one browser (Firefox), but not another.
+wc-reporter.tooltip=Adrodd ar fater cydnawsedd gwefan
diff --git a/l10n-cy/browser/firefox-l10n.js b/l10n-cy/browser/firefox-l10n.js
new file mode 100644
index 0000000000..b410ad9aef
--- /dev/null
+++ b/l10n-cy/browser/firefox-l10n.js
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#filter substitution
+
diff --git a/l10n-cy/browser/installer/custom.properties b/l10n-cy/browser/installer/custom.properties
new file mode 100644
index 0000000000..aad04a67ae
--- /dev/null
+++ b/l10n-cy/browser/installer/custom.properties
@@ -0,0 +1,92 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+REG_APP_DESC=Mae $BrandShortName yn cynnig pori gwe hawdd a diogel. Rhyngwyneb cyfarwydd, nodweddion diogelwch uwch yn cynnwys diogelwch rhag lladrad hunaniaeth ar-lein a chwilio integredig i gael y mwyaf allan o'r we.
+CONTEXT_OPTIONS=&Dewisiadau $BrandShortName
+CONTEXT_SAFE_MODE=&Modd Diogel $BrandShortName
+OPTIONS_PAGE_TITLE=Math o Osod
+OPTIONS_PAGE_SUBTITLE=Dewisiadau gosod
+SHORTCUTS_PAGE_TITLE=Llwybrau Byr y Gosod
+SHORTCUTS_PAGE_SUBTITLE=Creu Eiconau'r Rhaglen
+COMPONENTS_PAGE_TITLE=Gosod Cydrannau Ychwanegol
+COMPONENTS_PAGE_SUBTITLE=Cydrannau Dewisol Cymeradwy
+OPTIONAL_COMPONENTS_DESC=Bydd y Gwasanaeth Cynnal yn caniatáu i chi ddiweddaru $BrandShortName yn dawel yn y cefndir.
+MAINTENANCE_SERVICE_CHECKBOX_DESC=Gosod y &Gwasanaeth Cynnal
+SUMMARY_PAGE_TITLE=Crynodeb
+SUMMARY_PAGE_SUBTITLE=Yn barod i osod $BrandShortName
+SUMMARY_INSTALLED_TO=Bydd $BrandShortName yn cael ei osod yn y lleoliad canlynol:
+SUMMARY_REBOOT_REQUIRED_INSTALL=Efallai bydd angen ailgychwyn y cyfrifiadur er mwyn cwblhau'r gosod.
+SUMMARY_REBOOT_REQUIRED_UNINSTALL=Efallai bydd angen ailgychwyn y cyfrifiadur er mwyn cwblhau'r dadosod.
+SUMMARY_TAKE_DEFAULTS=&Defnyddio $BrandShortName fel y porwr rhagosodedig
+SUMMARY_INSTALL_CLICK=Clicio Gosod i barhau.
+SUMMARY_UPGRADE_CLICK=Clicio Diweddaru i barhau.
+SURVEY_TEXT=Dweud wr&thym eich barn am $BrandShortName
+LAUNCH_TEXT=&Cychwyn $BrandShortName nawr
+CREATE_ICONS_DESC=Creu eiconau $BrandShortName:
+ICONS_DESKTOP=Ar y &Bwrdd Gwaith
+ICONS_STARTMENU=Yn ffolder &Rhaglenni Dewislen Cychwyn
+ICONS_QUICKLAUNCH=Yn y bar &Cychwyn Cyflym
+WARN_MANUALLY_CLOSE_APP_INSTALL=Rhaid cau $BrandShortName er mwyn parhau gyda'r gosod.\n\nCaewch $BrandShortName er mwyn parhau.
+WARN_MANUALLY_CLOSE_APP_UNINSTALL=Rhaid cau $BrandShortName er mwyn parhau gyda'r dadosod.\n\nCaewch $BrandShortName er mwyn parhau.
+WARN_MANUALLY_CLOSE_APP_REFRESH=Rhaid fod $BrandShortName ar gau i barhau gyda'r adnewyddu.\n \n Caewch $BrandShortName i barhau.
+WARN_WRITE_ACCESS=Nid oes gennych fynediad i ysgrifennu i'r cyfeiriadur gosod.\n\nCliciwch Iawn i ddewis cyfeiriadur gwahanol.
+WARN_DISK_SPACE=Nid oes gennych ddigon o le ar ddisg i osod yn y lleoliad hwn.\n\nCliciwch Iawn i ddewis lleoliad gwahanol.
+WARN_MIN_SUPPORTED_OSVER_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} neu fwy diweddar. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedCPU} neu fwy diweddar. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_OSVER_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} a phrosesydd gyda chefnogaeth ar gyfer ${MinSupportedCPU}. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_RESTART_REQUIRED_UNINSTALL=Rhaid ailgychwyn y cyfrifiadur er mwyn cwblhau dadosod y fersiwn diwethaf o $BrandShortName. Hoffech chi ailgychwyn nawr?
+WARN_RESTART_REQUIRED_UPGRADE=Rhaid ailgychwyn y cyfrifiadur er mwyn cwblhau'r diweddariad diwethaf o $BrandShortName. Hoffech chi ailgychwyn nawr?
+ERROR_CREATE_DIRECTORY_PREFIX=Gwall wrth greu cyfeiriadur:
+ERROR_CREATE_DIRECTORY_SUFFIX=Cliciwch Diddymu i atal gosod neu\nEto er mwyn ceisio eto.
+
+UN_CONFIRM_PAGE_TITLE=Dad-osod $BrandFullName
+UN_CONFIRM_PAGE_SUBTITLE=Tynnu $BrandFullName oddi ar eich cyfrifiadur.
+UN_CONFIRM_UNINSTALLED_FROM=Bydd $BrandShortName yn cael ei ddadosod o'r ffolder canlynol:
+UN_CONFIRM_CLICK=Clicio Dadosod i barhau.
+
+UN_REFRESH_PAGE_TITLE=Adnewyddu $BrandShortName yn lle hynny?
+UN_REFRESH_PAGE_EXPLANATION=Os ydych yn cael anawsterau gyda $BrandShortName, gall ei adnewyddu helpu.\n \nBydd hyn yn adfer y gosodiadau rhagosodedig ac yn tynnu'r ychwanegion. Cychwynnwch o'r newydd ar gyfer y perfformiad gorau posibl.
+UN_REFRESH_LEARN_MORE=&Dysgu rhagor
+UN_REFRESH_BUTTON=&Adnewyddu $BrandShortName
+
+BANNER_CHECK_EXISTING=Gwirio'r gosodiad presennol…
+
+STATUS_INSTALL_APP=Gosod $BrandShortName…
+STATUS_INSTALL_LANG=Gosod Ffeiliau Iaith (${AB_CD})…
+STATUS_UNINSTALL_MAIN=Dadosod $BrandShortName…
+STATUS_CLEANUP=Ychydig o gadw trefn…
+
+UN_SURVEY_CHECKBOX_LABEL=Dweud wrth Mozilla pam eich bod wedi dadosod $BrandShortName
+
+# _DESC strings support approximately 65 characters per line.
+# One line
+OPTIONS_SUMMARY=Dewis y math o osod sydd orau gennych, yna clicio Nesaf.
+# One line
+OPTION_STANDARD_DESC=Bydd $BrandShortName yn cael ei osod gyda'r dewisiadau mwyaf cyffredin.
+OPTION_STANDARD_RADIO=&Safonol
+# Two lines
+OPTION_CUSTOM_DESC=Gallwch ddewis dewisiadau unigol i'w gosod. Ar gyfer defnyddwyr uwch.
+OPTION_CUSTOM_RADIO=&Cyfaddasu
+
+# LOCALIZATION NOTE:
+# The following text replaces the Install button text on the summary page.
+# Verify that the access key for InstallBtn (in override.properties) and
+# UPGRADE_BUTTON is not already used by SUMMARY_TAKE_DEFAULTS.
+UPGRADE_BUTTON=&Diweddaru
diff --git a/l10n-cy/browser/installer/mui.properties b/l10n-cy/browser/installer/mui.properties
new file mode 100644
index 0000000000..3d072b31bd
--- /dev/null
+++ b/l10n-cy/browser/installer/mui.properties
@@ -0,0 +1,61 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# To make the l10n tinderboxen see changes to this file you can change a value
+# name by adding - to the end of the name followed by chars (e.g. Branding-2).
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+MUI_TEXT_WELCOME_INFO_TITLE=Croeso i Ddewin Gosod $BrandFullNameDA
+MUI_TEXT_WELCOME_INFO_TEXT=Bydd y dewin yn eich tywys wrth osod $BrandFullNameDA.\n\nArgymhellir eich bod yn cau pob rhaglen arall cyn cychwyn gosod. Bydd hyn yn ei gwneud yn bosibl i ddiweddaru'r ffeiliau system berthnasol heb fod angen ailgychwyn eich cyfrifiadur.\n\n$_CLICK
+MUI_TEXT_COMPONENTS_TITLE=Dewis Cydrannau
+MUI_TEXT_COMPONENTS_SUBTITLE=Dewiswch pa nodweddion $BrandFullNameDA rydych am eu gosod.
+MUI_INNERTEXT_COMPONENTS_DESCRIPTION_TITLE=Disgrifiad
+MUI_INNERTEXT_COMPONENTS_DESCRIPTION_INFO=Rhowch eich llygoden ar draws cydran i weld ei ddisgrifiad.
+MUI_TEXT_DIRECTORY_TITLE=Dewis Lleoliad Gosod
+MUI_TEXT_DIRECTORY_SUBTITLE=Dewiswch y ffolder lle mae gosod $BrandFullNameDA.
+MUI_TEXT_INSTALLING_TITLE=Gosod
+MUI_TEXT_INSTALLING_SUBTITLE=Arhoswch tra bod $BrandFullNameDA yn cael ei osod.
+MUI_TEXT_FINISH_TITLE=Gosod wedi ei Gwblhau
+MUI_TEXT_FINISH_SUBTITLE=Gosod wedi ei gwblhau'n llwyddiannus.
+MUI_TEXT_ABORT_TITLE=Atalwyd y Gosod
+MUI_TEXT_ABORT_SUBTITLE=Ni chwblhawyd y gosod yn llwyddiannus.
+MUI_BUTTONTEXT_FINISH=Gor&ffen
+MUI_TEXT_FINISH_INFO_TITLE=Cwblhau Dewin Gosod $BrandFullNameDA
+MUI_TEXT_FINISH_INFO_TEXT=Mae $BrandFullNameDA. wedi'i osod ar eich cyfrifiadur.\n\nCliciwch Gorffen i gau'r dewin.
+MUI_TEXT_FINISH_INFO_REBOOT=Rhaid ailgychwyn eich cyfrifiadur er mwyn cwblhau gosod $BrandFullNameDA. Hoffech chi wneud hynny?
+MUI_TEXT_FINISH_REBOOTNOW=Ail gychwyn nawr
+MUI_TEXT_FINISH_REBOOTLATER=Rwyf am ailgychwyn yn ddiweddarach
+MUI_TEXT_STARTMENU_TITLE=Dewis Ffolder Dewislen Cychwyn
+MUI_TEXT_STARTMENU_SUBTITLE=Dewiswch ffolder Dewislen Cychwyn ar gyfer llwybrau byr $BrandFullNameDA.
+MUI_INNERTEXT_STARTMENU_TOP=Dewiswch ffolder Dewislen Cychwyn lle'r hoffech greu llwybrau byr y rhaglen. Gallwch osod enw i'r ffolder newydd.
+MUI_TEXT_ABORTWARNING=Ydych chi'n siŵr eich bod am adael Gosod $BrandFullName?
+MUI_UNTEXT_WELCOME_INFO_TITLE=Croeso i Ddewin Dadosod $BrandFullNameDA
+MUI_UNTEXT_WELCOME_INFO_TEXT=Bydd y dewin yn eich tywys drwy ddadosod $BrandFullNameDA.\n\nCyn cychwyn dadosod gwnewch yn siŵr nad yw $BrandFullNameDA yn rhedeg.\n\n$_CLICK
+MUI_UNTEXT_CONFIRM_TITLE=Dadosod $BrandFullNameDA
+MUI_UNTEXT_CONFIRM_SUBTITLE=Tynnu $BrandFullNameDA oddi ar eich cyfrifiadur.
+MUI_UNTEXT_UNINSTALLING_TITLE=Dadosod
+MUI_UNTEXT_UNINSTALLING_SUBTITLE=Arhoswch tra bo $BrandFullNameDA yn cael ei dadosod.
+MUI_UNTEXT_FINISH_TITLE=Dadosod wedi ei gwblhau
+MUI_UNTEXT_FINISH_SUBTITLE=Dadosod wedi ei gwblhau'n llwyddiannus.
+MUI_UNTEXT_ABORT_TITLE=Atal y Dadosod
+MUI_UNTEXT_ABORT_SUBTITLE=Ni chwyblhawyd y dadosod yn llwyddiannus.
+MUI_UNTEXT_FINISH_INFO_TITLE=Cwblhau Dewin Dadosod $BrandFullNameDA
+MUI_UNTEXT_FINISH_INFO_TEXT=Mae $BrandFullNameDA wedi ei dadosod o'ch cyfrifiadur.\n\nCliciwch Gorffen i gau'r dewin.
+MUI_UNTEXT_FINISH_INFO_REBOOT=Rhaid ailgychwyn eich cyfrifiadur er mwyn cwblhau dadosod $BrandFullNameDA. Hoffech chi ailgychwyn?
+MUI_UNTEXT_ABORTWARNING=Ydych chi'n siŵr eich bod am adael dadosod $BrandFullName Uninstall?
diff --git a/l10n-cy/browser/installer/nsisstrings.properties b/l10n-cy/browser/installer/nsisstrings.properties
new file mode 100644
index 0000000000..017ead4d64
--- /dev/null
+++ b/l10n-cy/browser/installer/nsisstrings.properties
@@ -0,0 +1,50 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandProductName, $BrandFullName,
+# or $BrandFullNameDA with a custom string and always use the same one as used
+# by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+INSTALLER_WIN_CAPTION=Gosodwr $BrandShortName
+
+STUB_CLEANUP_PAVEOVER_HEADER2=Mae $BrandShortName eisoes wedi ei osod. Gadewch i ni ei ddiweddaru.
+STUB_CLEANUP_REINSTALL_HEADER2=Mae $BrandShortName wedi ei osod o'r blaen. Beth am i ni osod copi newydd.
+
+STUB_CLEANUP_PAVEOVER_BUTTON2=Diweddaru
+STUB_CLEANUP_REINSTALL_BUTTON2=Ail-osod
+STUB_CLEANUP_CHECKBOX_LABEL2=Adfer y gosodiadau rhagosodedig a thynnu hen ychwanegion ar gyfer y perfformiad gorau
+
+STUB_INSTALLING_LABEL2=Wrthi'n gosod…
+STUB_INSTALLING_HEADLINE2=Optimeiddio'ch gosodiadau ar gyfer cyflymder, preifatrwydd a diogelwch.
+STUB_INSTALLING_BODY2=Bydd $BrandShortName yn barod mewn ychydig eiliadau.
+STUB_BLURB_FIRST1=Y $BrandShortName cyflymaf a mwyaf ymatebol eto
+STUB_BLURB_SECOND1=Llwytho tudalennau a newid tabiau yn gynt
+STUB_BLURB_THIRD1=Pori preifat pwerus
+STUB_BLURB_FOOTER2=Ar gyfer pobl, nid elw
+
+WARN_MIN_SUPPORTED_OSVER_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} neu fwy diweddar. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen prosesydd gyda chefnogaeth ar gyfer ${MinSupportedCPU}. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_OSVER_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} a phrosesydd gyda chefnogaeth ar gyfer ${MinSupportedCPU}. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_WRITE_ACCESS_QUIT=Nid oes gennych fynediad i ysgrifennu i'r cyfeiriadur gosod
+WARN_DISK_SPACE_QUIT=Nid oes gennych ddigon o le ar ddisg i'w osod.
+
+ERROR_DOWNLOAD_CONT=Hmm. Am rhyw reswm, nid oedd modd i ni osod $BrandShortName.\nCliciwch Iawn i gychwyn eto.
+
+STUB_CANCEL_PROMPT_HEADING=Ydych chi am osod $BrandShortName?
+STUB_CANCEL_PROMPT_MESSAGE=Os fyddwch yn diddymu, ni fydd $BrandShortName yn cael ei osod.
+STUB_CANCEL_PROMPT_BUTTON_CONTINUE=Gosod $BrandShortName
+STUB_CANCEL_PROMPT_BUTTON_EXIT=Diddymu
diff --git a/l10n-cy/browser/installer/override.properties b/l10n-cy/browser/installer/override.properties
new file mode 100644
index 0000000000..fdd29800a7
--- /dev/null
+++ b/l10n-cy/browser/installer/override.properties
@@ -0,0 +1,86 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+# Strings that require a space at the end should be enclosed with double
+# quotes and the double quotes will be removed. To add quotes to the beginning
+# and end of a strong enclose the add and additional double quote to the
+# beginning and end of the string (e.g. ""This will include quotes"").
+
+SetupCaption=Gosod $BrandFullName
+UninstallCaption=Dadosod $BrandFullName
+BackBtn=< &Nôl
+NextBtn=N&esaf >
+AcceptBtn=Rwy'n &derbyn amodau'r Cytundeb Trwyddedu
+DontAcceptBtn=&Nid wyf yn derbyn amodau'r Cytundeb Trwyddedu
+InstallBtn=&Gosod
+UninstallBtn=&Dadosod
+CancelBtn=Diddymu
+CloseBtn=&Cau
+BrowseBtn=&Pori…
+ShowDetailsBtn=&Dangos manylion
+ClickNext=Clicio Nesaf i barhau.
+ClickInstall=Clicio Gosod i gychwyn gosod.
+ClickUninstall=Cliciwch Dadosod i gychwyn dadosod.
+Completed=Cwblhawyd
+LicenseTextRB=Darllenwch y cytundeb trwyddedu cyn gosod $BrandFullNameDA. Os ydych yn derbyn amodau’r cytundeb, dewiswch y dewis cyntaf isod. $_CLICK
+ComponentsText=Ticiwch y cydrannau rydych am eu gosod a dad dicio'r cydrannau nad ydych am eu gosod. $_CLICK
+ComponentsSubText2_NoInstTypes=Dewiswch gydrannau i'w gosod:
+DirText=Bydd y gosod yn gosod $BrandFullNameDA yn y ffolder canlynol. I'w osod mewn ffolder gwahanol, cliciwch Pori a dewis ffolder arall. $_CLICK
+DirSubText=Ffolder Cyrchfan
+DirBrowseText=Dewiswch y ffolder i osod $BrandFullNameDA ynddi:
+SpaceAvailable="Lle ar gael: "
+SpaceRequired="Lle angenrheidiol: "
+UninstallingText=Bydd $BrandFullNameDA yn cael ei ddadosod o'r ffolder canlynol. $_CLICK
+UninstallingSubText=Dadosod o:
+FileError=Gwall wrth agor ffeil i'w ysgrifennu: \r\n\r\n$0\r\n\r\nCiciwch Atal i atal y gosod,\r\nAil-geisio i geisio eto neu\r\nAnwybyddu i hepgor y ffeil.
+FileError_NoIgnore=Gwall wrth agor ffeil i'w ysgrifennu: \r\n\r\n$0\r\n\r\nAil-geisio i geisio eto neu\r\nDiddymu i atal y gosod.
+CantWrite="Methu ysgrifennu: "
+CopyFailed=Methodd copïo
+CopyTo="Copïo i "
+Registering="Cofrestru: "
+Unregistering="Dadgofrestru: "
+SymbolNotFound="Methu canfod symbol: "
+CouldNotLoad="Methu llwytho: "
+CreateFolder="Creu ffolder: "
+CreateShortcut="Creu llwybr byr: "
+CreatedUninstaller="Creu dadosodwr: "
+Delete="Dileu ffeil: "
+DeleteOnReboot="Dileu wrth ailgychwyn: "
+ErrorCreatingShortcut="Gwall wrth greu llwybr byr: "
+ErrorCreating="Creu gwall: "
+ErrorDecompressing=Gwall wrth ddatgywasgu data! Gosodwr llwgr?
+ErrorRegistering=Gwall cofrestru DLL
+ExecShell="ExecShell: "
+Exec="Gweithredu: "
+Extract="Echdynnu: "
+ErrorWriting="Echdynnu: gwall ysgrifennu i ffeil "
+InvalidOpcode=Gosodwr gwallus: opcode annilys
+NoOLE="Dim OLE ar gyfer: "
+OutputFolder="Ffolder allbwn: "
+RemoveFolder="Tynnu ffolder: "
+RenameOnReboot="Ailenwi wrth ailgychwyn: "
+Rename="Ailenwi: "
+Skipped="Hepgorwyd: "
+CopyDetails=Copïo Manylion i'r Clipfwrdd
+LogInstall=Cofnodi'r broses gosod
+Byte=B
+Kilo=K
+Mega=M
+Giga=G
diff --git a/l10n-cy/browser/pdfviewer/chrome.properties b/l10n-cy/browser/pdfviewer/chrome.properties
new file mode 100644
index 0000000000..7a68b5a62b
--- /dev/null
+++ b/l10n-cy/browser/pdfviewer/chrome.properties
@@ -0,0 +1,19 @@
+# Copyright 2012 Mozilla Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Chrome notification bar messages and buttons
+unsupported_feature=Efallai na fydd y ddogfen PDF yn cael ei dangos yn gywir.
+unsupported_feature_forms=Mae'r ffurflen PDF hon yn cynnwys ffurflenni. Nid yw llanw ffurflenni'n cael ei gynnal.
+open_with_different_viewer=Agor gyda Darllenydd Gwahanol
+open_with_different_viewer.accessKey=o
diff --git a/l10n-cy/browser/pdfviewer/viewer.properties b/l10n-cy/browser/pdfviewer/viewer.properties
new file mode 100644
index 0000000000..3f819c2be5
--- /dev/null
+++ b/l10n-cy/browser/pdfviewer/viewer.properties
@@ -0,0 +1,253 @@
+# Copyright 2012 Mozilla Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Main toolbar buttons (tooltips and alt text for images)
+previous.title=Tudalen Flaenorol
+previous_label=Blaenorol
+next.title=Tudalen Nesaf
+next_label=Nesaf
+
+# LOCALIZATION NOTE (page.title): The tooltip for the pageNumber input.
+page.title=Tudalen
+# LOCALIZATION NOTE (of_pages): "{{pagesCount}}" will be replaced by a number
+# representing the total number of pages in the document.
+of_pages=o {{pagesCount}}
+# LOCALIZATION NOTE (page_of_pages): "{{pageNumber}}" and "{{pagesCount}}"
+# will be replaced by a number representing the currently visible page,
+# respectively a number representing the total number of pages in the document.
+page_of_pages=({{pageNumber}} o {{pagesCount}})
+
+zoom_out.title=Chwyddo Allan
+zoom_out_label=Chwyddo Allan
+zoom_in.title=Chwyddo Mewn
+zoom_in_label=Chwyddo Mewn
+zoom.title=Chwyddo
+presentation_mode.title=Newid i'r Modd Cyflwyno
+presentation_mode_label=Modd Cyflwyno
+open_file.title=Agor Ffeil
+open_file_label=Agor
+print.title=Argraffu
+print_label=Argraffu
+download.title=Llwyth
+download_label=Llwytho i Lawr
+bookmark.title=Golwg cyfredol (copïo neu agor ffenestr newydd)
+bookmark_label=Golwg Gyfredol
+
+# Secondary toolbar and context menu
+tools.title=Offer
+tools_label=Offer
+first_page.title=Mynd i'r Dudalen Gyntaf
+first_page.label=Mynd i'r Dudalen Gyntaf
+first_page_label=Mynd i'r Dudalen Gyntaf
+last_page.title=Mynd i'r Dudalen Olaf
+last_page.label=Mynd i'r Dudalen Olaf
+last_page_label=Mynd i'r Dudalen Olaf
+page_rotate_cw.title=Cylchdroi Clocwedd
+page_rotate_cw.label=Cylchdroi Clocwedd
+page_rotate_cw_label=Cylchdroi Clocwedd
+page_rotate_ccw.title=Cylchdroi Gwrthglocwedd
+page_rotate_ccw.label=Cylchdroi Gwrthglocwedd
+page_rotate_ccw_label=Cylchdroi Gwrthglocwedd
+
+cursor_text_select_tool.title=Galluogi Dewis Offeryn Testun
+cursor_text_select_tool_label=Offeryn Dewis Testun
+cursor_hand_tool.title=Galluogi Offeryn Llaw
+cursor_hand_tool_label=Offeryn Llaw
+
+scroll_vertical.title=Defnyddio Sgrolio Fertigol
+scroll_vertical_label=Sgrolio Fertigol
+scroll_horizontal.title=Defnyddio Sgrolio Fertigol
+scroll_horizontal_label=Sgrolio Fertigol
+scroll_wrapped.title=Defnyddio Sgrolio Amlapio
+scroll_wrapped_label=Sgrolio Amlapio
+
+spread_none.title=Peidio uno taeniadau canol
+spread_none_label=Dim Taeniadau
+spread_odd.title=Uno taeniadau tudalen yn cychwyn gyda thudalennau odrif
+spread_odd_label=Taeniadau Odrifau
+spread_even.title=Uno taeniadau tudalen yn cychwyn gyda thudalennau eilrif
+spread_even_label=Taeniadau Eilrif
+
+# Document properties dialog box
+document_properties.title=Priodweddau Dogfen…
+document_properties_label=Priodweddau Dogfen…
+document_properties_file_name=Enw ffeil:
+document_properties_file_size=Maint ffeil:
+# LOCALIZATION NOTE (document_properties_kb): "{{size_kb}}" and "{{size_b}}"
+# will be replaced by the PDF file size in kilobytes, respectively in bytes.
+document_properties_kb={{size_kb}} KB ({{size_b}} beit)
+# LOCALIZATION NOTE (document_properties_mb): "{{size_mb}}" and "{{size_b}}"
+# will be replaced by the PDF file size in megabytes, respectively in bytes.
+document_properties_mb={{size_mb}} MB ({{size_b}} beit)
+document_properties_title=Teitl:
+document_properties_author=Awdur:
+document_properties_subject=Pwnc:
+document_properties_keywords=Allweddair:
+document_properties_creation_date=Dyddiad Creu:
+document_properties_modification_date=Dyddiad Addasu:
+# LOCALIZATION NOTE (document_properties_date_string): "{{date}}" and "{{time}}"
+# will be replaced by the creation/modification date, and time, of the PDF file.
+document_properties_date_string={{date}}, {{time}}
+document_properties_creator=Crewr:
+document_properties_producer=Cynhyrchydd PDF:
+document_properties_version=Fersiwn PDF:
+document_properties_page_count=Cyfrif Tudalen:
+document_properties_page_size=Maint Tudalen:
+document_properties_page_size_unit_inches=o fewn
+document_properties_page_size_unit_millimeters=mm
+document_properties_page_size_orientation_portrait=portread
+document_properties_page_size_orientation_landscape=tirlun
+document_properties_page_size_name_a3=A3
+document_properties_page_size_name_a4=A4
+document_properties_page_size_name_letter=Llythyr
+document_properties_page_size_name_legal=Cyfreithiol
+# LOCALIZATION NOTE (document_properties_page_size_dimension_string):
+# "{{width}}", "{{height}}", {{unit}}, and {{orientation}} will be replaced by
+# the size, respectively their unit of measurement and orientation, of the (current) page.
+document_properties_page_size_dimension_string={{width}} × {{height}} {{unit}} ({{orientation}})
+# LOCALIZATION NOTE (document_properties_page_size_dimension_name_string):
+# "{{width}}", "{{height}}", {{unit}}, {{name}}, and {{orientation}} will be replaced by
+# the size, respectively their unit of measurement, name, and orientation, of the (current) page.
+document_properties_page_size_dimension_name_string={{width}} × {{height}} {{unit}} ({{name}}, {{orientation}})
+# LOCALIZATION NOTE (document_properties_linearized): The linearization status of
+# the document; usually called "Fast Web View" in English locales of Adobe software.
+document_properties_linearized=Golwg Gwe Cyflym:
+document_properties_linearized_yes=Iawn
+document_properties_linearized_no=Na
+document_properties_close=Cau
+
+print_progress_message=Paratoi dogfen ar gyfer ei hargraffu…
+# LOCALIZATION NOTE (print_progress_percent): "{{progress}}" will be replaced by
+# a numerical per cent value.
+print_progress_percent={{progress}}%
+print_progress_close=Diddymu
+
+# Tooltips and alt text for side panel toolbar buttons
+# (the _label strings are alt text for the buttons, the .title strings are
+# tooltips)
+toggle_sidebar.title=Toglo'r Bar Ochr
+toggle_sidebar_notification.title=Toglo'r Bar Ochr (mae'r ddogfen yn cynnwys outline/attachments)
+toggle_sidebar_notification2.title=Toglo'r Bar Ochr (mae'r ddogfen yn cynnwys amlinelliadau/atodiadau/haenau)
+toggle_sidebar_label=Toglo'r Bar Ochr
+document_outline.title=Dangos Amlinell Dogfen (clic dwbl i ymestyn/cau pob eitem)
+document_outline_label=Amlinelliad Dogfen
+attachments.title=Dangos Atodiadau
+attachments_label=Atodiadau
+layers.title=Dangos Haenau (cliciwch ddwywaith i ailosod yr holl haenau i'r cyflwr rhagosodedig)
+layers_label=Haenau
+thumbs.title=Dangos Lluniau Bach
+thumbs_label=Lluniau Bach
+current_outline_item.title=Canfod yr Eitem Amlinellol Gyfredol
+current_outline_item_label=Yr Eitem Amlinellol Gyfredol
+findbar.title=Canfod yn y Ddogfen
+findbar_label=Canfod
+
+additional_layers=Haenau Ychwanegol
+# LOCALIZATION NOTE (page_canvas): "{{page}}" will be replaced by the page number.
+page_canvas=Tudalen {{page}}
+# Thumbnails panel item (tooltip and alt text for images)
+# LOCALIZATION NOTE (thumb_page_title): "{{page}}" will be replaced by the page
+# number.
+thumb_page_title=Tudalen {{page}}
+# LOCALIZATION NOTE (thumb_page_canvas): "{{page}}" will be replaced by the page
+# number.
+thumb_page_canvas=Llun Bach Tudalen {{page}}
+
+# Find panel button title and messages
+find_input.title=Canfod
+find_input.placeholder=Canfod yn y ddogfen…
+find_previous.title=Canfod enghraifft flaenorol o'r ymadrodd
+find_previous_label=Blaenorol
+find_next.title=Canfod enghraifft nesaf yr ymadrodd
+find_next_label=Nesaf
+find_highlight=Amlygu popeth
+find_match_case_label=Cydweddu maint
+find_entire_word_label=Geiriau cyfan
+find_reached_top=Wedi cyrraedd brig y dudalen, parhau o'r gwaelod
+find_reached_bottom=Wedi cyrraedd diwedd y dudalen, parhau o'r brig
+# LOCALIZATION NOTE (find_match_count): The supported plural forms are
+# [one|two|few|many|other], with [other] as the default value.
+# "{{current}}" and "{{total}}" will be replaced by a number representing the
+# index of the currently active find result, respectively a number representing
+# the total number of matches in the document.
+find_match_count={[ plural(total) ]}
+find_match_count[one]={{current}} o {{total}} cydweddiad
+find_match_count[two]={{current}} o {{total}} cydweddiad
+find_match_count[few]={{current}} o {{total}} cydweddiad
+find_match_count[many]={{current}} o {{total}} cydweddiad
+find_match_count[other]={{current}} o {{total}} cydweddiad
+# LOCALIZATION NOTE (find_match_count_limit): The supported plural forms are
+# [zero|one|two|few|many|other], with [other] as the default value.
+# "{{limit}}" will be replaced by a numerical value.
+find_match_count_limit={[ plural(limit) ]}
+find_match_count_limit[zero]=Mwy na {{limit}} cydweddiad
+find_match_count_limit[one]=Mwy na {{limit}} cydweddiad
+find_match_count_limit[two]=Mwy na {{limit}} cydweddiad
+find_match_count_limit[few]=Mwy na {{limit}} cydweddiad
+find_match_count_limit[many]=Mwy na {{limit}} cydweddiad
+find_match_count_limit[other]=Mwy na {{limit}} cydweddiad
+find_not_found=Heb ganfod ymadrodd
+
+# Error panel labels
+error_more_info=Rhagor o Wybodaeth
+error_less_info=Llai o wybodaeth
+error_close=Cau
+# LOCALIZATION NOTE (error_version_info): "{{version}}" and "{{build}}" will be
+# replaced by the PDF.JS version and build ID.
+error_version_info=PDF.js v{{version}} (build: {{build}})
+# LOCALIZATION NOTE (error_message): "{{message}}" will be replaced by an
+# english string describing the error.
+error_message=Neges: {{message}}
+# LOCALIZATION NOTE (error_stack): "{{stack}}" will be replaced with a stack
+# trace.
+error_stack=Stac: {{stack}}
+# LOCALIZATION NOTE (error_file): "{{file}}" will be replaced with a filename
+error_file=Ffeil: {{file}}
+# LOCALIZATION NOTE (error_line): "{{line}}" will be replaced with a line number
+error_line=Llinell: {{line}}
+rendering_error=Digwyddodd gwall wrth adeiladu'r dudalen.
+
+# Predefined zoom values
+page_scale_width=Lled Tudalen
+page_scale_fit=Ffit Tudalen
+page_scale_auto=Chwyddo Awtomatig
+page_scale_actual=Maint Gwirioneddol
+# LOCALIZATION NOTE (page_scale_percent): "{{scale}}" will be replaced by a
+# numerical scale value.
+page_scale_percent={{scale}}%
+
+# Loading indicator messages
+loading_error_indicator=Gwall
+loading_error=Digwyddodd gwall wrth lwytho'r PDF.
+invalid_file_error=Ffeil PDF annilys neu llwgr.
+missing_file_error=Ffeil PDF coll.
+unexpected_response_error=Ymateb annisgwyl gan y gweinydd.
+
+# LOCALIZATION NOTE (annotation_date_string): "{{date}}" and "{{time}}" will be
+# replaced by the modification date, and time, of the annotation.
+annotation_date_string={{date}}, {{time}}
+
+# LOCALIZATION NOTE (text_annotation_type.alt): This is used as a tooltip.
+# "{{type}}" will be replaced with an annotation type from a list defined in
+# the PDF spec (32000-1:2008 Table 169 – Annotation types).
+# Some common types are e.g.: "Check", "Text", "Comment", "Note"
+text_annotation_type.alt=[Anodiad {{type}} ]
+password_label=Rhowch gyfrinair i agor y PDF.
+password_invalid=Cyfrinair annilys. Ceisiwch eto.
+password_ok=Iawn
+password_cancel=Diddymu
+
+printing_not_supported=Rhybudd: Nid yw argraffu yn cael ei gynnal yn llawn gan y porwr.
+printing_not_ready=Rhybudd: Nid yw'r PDF wedi ei lwytho'n llawn ar gyfer argraffu.
+web_fonts_disabled=Ffontiau gwe wedi eu hanalluogi: methu defnyddio ffontiau PDF mewnblanedig.
diff --git a/l10n-cy/browser/profile/bookmarks.inc b/l10n-cy/browser/profile/bookmarks.inc
new file mode 100644
index 0000000000..2e08a67dad
--- /dev/null
+++ b/l10n-cy/browser/profile/bookmarks.inc
@@ -0,0 +1,151 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#filter emptyLines
+
+# LOCALIZATION NOTE: The 'en-US' strings in the URLs will be replaced with
+
+# your locale code, and link to your translated pages as soon as they're
+
+# live.
+
+
+#define bookmarks_title Nodau Tudalen
+
+
+#define bookmarks_heading Nodau Tudalen
+
+
+#define bookmarks_toolbarfolder Ffolder Bar Offer Nodau Tudalen
+
+
+#define bookmarks_toolbarfolder_description Ychwanegu nodau tudalen i'r ffolder hwn i'w gweld ym Mar Offer Nodau Tudalen
+
+
+# LOCALIZATION NOTE (getting_started):
+
+
+# link title for https://www.mozilla.org/en-US/firefox/central/
+
+
+#define getting_started Cychwyn Arni
+
+
+# LOCALIZATION NOTE (firefox_heading):
+
+
+# Firefox links folder name
+
+
+#define firefox_heading Mozilla Firefox
+
+
+# LOCALIZATION NOTE (firefox_help):
+
+
+# link title for https://www.mozilla.org/en-US/firefox/help/
+
+
+#define firefox_help Cymorth a Thiwtorialau
+
+
+# LOCALIZATION NOTE (firefox_customize):
+
+
+# link title for https://www.mozilla.org/en-US/firefox/customize/
+
+
+#define firefox_customize Cyfaddasu Firefox
+
+
+# LOCALIZATION NOTE (firefox_community):
+
+
+# link title for https://www.mozilla.org/en-US/contribute/
+
+
+#define firefox_community Cyfranogi
+
+
+# LOCALIZATION NOTE (firefox_about):
+
+
+# link title for https://www.mozilla.org/en-US/about/
+
+
+#define firefox_about Amdanom Ni
+
+
+# LOCALIZATION NOTE (nightly_heading):
+
+
+# Firefox Nightly links folder name
+
+
+#define nightly_heading Adnoddau Firefox Nightly
+
+
+# LOCALIZATION NOTE (nightly_blog):
+
+
+# Nightly builds only, link title for https://blog.nightly.mozilla.org/
+
+
+#define nightly_blog Blog Firefox Nightly
+
+
+# LOCALIZATION NOTE (bugzilla):
+
+
+# Nightly builds only, link title for https://bugzilla.mozilla.org/
+
+
+#define bugzilla Traciwr Gwallau Mozilla
+
+
+# LOCALIZATION NOTE (mdn):
+
+
+# Nightly builds only, link title for https://developer.mozilla.org/
+
+
+#define mdn Rhwydwaith Datblygwyr Mozilla
+
+
+# LOCALIZATION NOTE (nightly_tester_tools):
+
+
+# Nightly builds only, link title for https://addons.mozilla.org/en-US/firefox/addon/nightly-tester-tools/
+
+
+#define nightly_tester_tools Offer Profi Nightly
+
+
+# LOCALIZATION NOTE (crashes):
+
+
+# Nightly builds only, link title for about:crashes
+
+
+#define crashes Pob Chwalfa
+
+
+# LOCALIZATION NOTE (irc):
+
+
+# Nightly builds only, link title for ircs://irc.mozilla.org/nightly
+
+
+#define irc Trafod Nightly ar IRC
+
+
+# LOCALIZATION NOTE (planet):
+
+
+# Nightly builds only, link title for https://planet.mozilla.org/
+
+
+#define planet Planet Mozilla
+
+
+#unfilter emptyLines
diff --git a/l10n-cy/browser/updater/updater.ini b/l10n-cy/browser/updater/updater.ini
new file mode 100644
index 0000000000..9944ebe4f7
--- /dev/null
+++ b/l10n-cy/browser/updater/updater.ini
@@ -0,0 +1,9 @@
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0. If a copy of the MPL was not distributed with this
+; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+; This file is in the UTF-8 encoding
+; All strings must be less than 600 chars.
+[Strings]
+TitleText=Diweddaru %MOZ_APP_DISPLAYNAME%
+InfoText=Mae %MOZ_APP_DISPLAYNAME% yn gosod eich diweddariadau a bydd yn cychwyn ymhen ychydig…
+MozillaMaintenanceDescription=Mae'r Mozilla Maintenance Service yn sicrhau fod gennych y fersiwn mwyaf diweddar a diogel o Mozilla Firefox ar eich cyfrifiadur. Mae cadw Firefox yn gyfredol yn bwysig iawn ar gyfer eich diogelwch ar-lein, ac mae Mozilla yn eich annog yn gryf i gadw'r gwasanaeth yma wedi ei alluogi.
diff --git a/l10n-cy/calendar/README.txt b/l10n-cy/calendar/README.txt
new file mode 100644
index 0000000000..927fc142f2
--- /dev/null
+++ b/l10n-cy/calendar/README.txt
@@ -0,0 +1,3 @@
+For information about installing, running and configuring Sunbird 
+including a list of known issues and troubleshooting information, 
+refer to: http://www.mozilla.org/projects/calendar/
diff --git a/l10n-cy/calendar/calendar/calendar-context-menus.ftl b/l10n-cy/calendar/calendar/calendar-context-menus.ftl
new file mode 100644
index 0000000000..a6a06b5e0b
--- /dev/null
+++ b/l10n-cy/calendar/calendar/calendar-context-menus.ftl
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-item-context-menu-modify-menuitem =
+    .label = Golygu
+    .accesskey = G
diff --git a/l10n-cy/calendar/calendar/calendar-ics-file-dialog.ftl b/l10n-cy/calendar/calendar/calendar-ics-file-dialog.ftl
new file mode 100644
index 0000000000..f088cf9d97
--- /dev/null
+++ b/l10n-cy/calendar/calendar/calendar-ics-file-dialog.ftl
@@ -0,0 +1,39 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-ics-file-window-2 =
+    .title = Mewnforio Digwyddiadau a Thasgau Calendr
+calendar-ics-file-dialog-import-event-button-label = Mewnforio Digwyddiadau
+calendar-ics-file-dialog-import-task-button-label = Mewnforio Tasg
+calendar-ics-file-dialog-2 =
+    .buttonlabelaccept = Mewnforio'r Cyfan
+calendar-ics-file-accept-button-ok-label = Iawn
+calendar-ics-file-cancel-button-close-label = Cau
+calendar-ics-file-dialog-message-2 = Mewnforio o'r ffeil:
+calendar-ics-file-dialog-calendar-menu-label = Mewnforio i'r calendr:
+calendar-ics-file-dialog-items-loading-message =
+    .value = Llwytho eitemau...
+calendar-ics-file-dialog-progress-message = Mewnforio…
+calendar-ics-file-import-success = Wedi’i mewnforio’n llwyddiannus
+calendar-ics-file-import-error = Digwyddodd gwall a methodd y mewnforio.
+calendar-ics-file-import-complete = Mewnforio wedi'i gwblhau.
+calendar-ics-file-import-duplicates =
+    { $duplicatesCount ->
+        [zero] Anwybyddwyd dim eitemau.
+        [one] Anwybyddwyd un eitem gan ei bod eisoes yn bodoli yn y calendr cyrchfan.
+        [two] Anwybyddwyd { $duplicatesCount } eitem gan eu bod eisoes yn bodoli yn y calendr cyrchfan.
+        [few] Anwybyddwyd { $duplicatesCount } eitem gan eu bod eisoes yn bodoli yn y calendr cyrchfan.
+        [many] Anwybyddwyd { $duplicatesCount } eitem gan eu bod eisoes yn bodoli yn y calendr cyrchfan.
+       *[other] Anwybyddwyd { $duplicatesCount } eitem gan eu bod eisoes yn bodoli yn y calendr cyrchfan.
+    }
+calendar-ics-file-import-errors =
+    { $errorsCount ->
+        [zero] Methodd mewnforio dim eitemau.
+        [one] Methodd mewnforio un eitem. Gwiriwch y Consol Gwall am fanylion.
+        [two] Methodd mewnforio { $errorCount } eitem. Gwiriwch y Consol Gwall am fanylion.
+        [few] Methodd mewnforio { $errorCount } eitem. Gwiriwch y Consol Gwall am fanylion.
+        [many] Methodd mewnforio { $errorCount } eitem. Gwiriwch y Consol Gwall am fanylion.
+       *[other] Methodd mewnforio { $errorCount } eitem. Gwiriwch y Consol Gwall am fanylion.
+    }
+calendar-ics-file-dialog-no-calendars = Nid oes unrhyw galendrau sy'n gallu mewnforio digwyddiadau neu dasgau.
diff --git a/l10n-cy/calendar/calendar/calendar-summary-dialog.ftl b/l10n-cy/calendar/calendar/calendar-summary-dialog.ftl
new file mode 100644
index 0000000000..b444f9b494
--- /dev/null
+++ b/l10n-cy/calendar/calendar/calendar-summary-dialog.ftl
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-summary-dialog-edit-button =
+    .label = Golygu
+    .accesskey = G
+calendar-summary-dialog-edit-menu-button =
+    .label = Golygu
+edit-button-context-menu-this-occurrence =
+    .label = Golygu'r digwyddiad yma
+    .accesskey = d
+edit-button-context-menu-all-occurrences =
+    .label = Golygu pob digwyddiad
+    .accesskey = p
diff --git a/l10n-cy/calendar/calendar/calendar-uri-redirect-dialog.ftl b/l10n-cy/calendar/calendar/calendar-uri-redirect-dialog.ftl
new file mode 100644
index 0000000000..5dda2dfb60
--- /dev/null
+++ b/l10n-cy/calendar/calendar/calendar-uri-redirect-dialog.ftl
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-uri-redirect-window =
+    .title = Ailgyfeirio URI Calendr
+calendar-uri-redirect-description =
+    Mae'r gweinydd yn ailgyfeirio URI calendr "{ $calendarName }".
+    Derbyn yr ailgyfeirio a dechrau defnyddio'r URI newydd ar gyfer y calendr hwn?
+calendar-uri-redirect-original-uri-label = URI cyfredol:
+calendar-uri-redirect-target-uri-label = Ailgyfeirio i URI newydd:
diff --git a/l10n-cy/calendar/calendar/calendar-widgets.ftl b/l10n-cy/calendar/calendar/calendar-widgets.ftl
new file mode 100644
index 0000000000..82e617a9bd
--- /dev/null
+++ b/l10n-cy/calendar/calendar/calendar-widgets.ftl
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-deactivated-notification-events = Mae pob calendr wedi'i analluogi ar hyn o bryd. Galluogwch galendr sy'n bodoli eisoes neu ychwanegu un newydd i greu a golygu digwyddiadau.
+calendar-deactivated-notification-tasks = Mae pob calendr wedi'i analluogi ar hyn o bryd. Galluogwch galendr sy'n bodoli eisoes neu ychwanegu un newydd i greu a golygu tasgau.
diff --git a/l10n-cy/calendar/calendar/category-dialog.ftl b/l10n-cy/calendar/calendar/category-dialog.ftl
new file mode 100644
index 0000000000..671344e375
--- /dev/null
+++ b/l10n-cy/calendar/calendar/category-dialog.ftl
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+category-name-label = Enw
+category-color-label =
+    .label = Defnyddio Lliw
diff --git a/l10n-cy/calendar/calendar/preferences.ftl b/l10n-cy/calendar/calendar/preferences.ftl
new file mode 100644
index 0000000000..a1b51b347f
--- /dev/null
+++ b/l10n-cy/calendar/calendar/preferences.ftl
@@ -0,0 +1,186 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+calendar-title = Calendr
+calendar-title-reminder = Atgoffwyr
+calendar-title-category = Categorïau
+dateformat-label =
+    .value = Fformat Testun Dyddiad:
+    .accesskey = F
+#   $date (String) - the formatted example date
+dateformat-long =
+    .label = Hir: { $date }
+#   $date (String) - the formatted example date
+dateformat-short =
+    .label = Byr: { $date }
+timezone-label =
+    .value = Cylch Amser:
+weekstart-label =
+    .value = Cychwyn yr wythnos ar:
+    .accesskey = C
+day-1-name =
+    .label = Dydd Sul
+day-2-name =
+    .label = Dydd Llun
+day-3-name =
+    .label = Dydd Mawrth
+day-4-name =
+    .label = Dydd Mercher
+day-5-name =
+    .label = Dydd Iau
+day-6-name =
+    .label = Dydd Gwener
+day-7-name =
+    .label = Dydd Sadwrn
+show-weeknumber-label =
+    .label = Dangos rhif wythnos mewn golwg a mis bach
+    .accesskey = r
+workdays-label =
+    .value = Diwrnodau wythnos gwaith:
+day-1-checkbox =
+    .label = Sul
+    .accesskey = S
+day-2-checkbox =
+    .label = Llu
+    .accesskey = L
+day-3-checkbox =
+    .label = Maw
+    .accesskey = M
+day-4-checkbox =
+    .label = Mer
+    .accesskey = e
+day-5-checkbox =
+    .label = Iau
+    .accesskey = I
+day-6-checkbox =
+    .label = Gwe
+    .accesskey = G
+day-7-checkbox =
+    .label = Sad
+    .accesskey = a
+dayweek-legend = Golwg Diwrnod ac Wythnos
+visible-hours-label =
+    .value = Dangos:
+    .accesskey = a
+visible-hours-end-label =
+    .value = awr ar y tro
+day-start-label =
+    .value = Diwrnod yn cychwyn:
+    .accesskey = D
+day-end-label =
+    .value = Diwrnod yn gorffen:
+    .accesskey = i
+midnight-label =
+    .label = Canol Nos
+noon-label =
+    .label = Canol Dydd
+location-checkbox =
+    .label = Dangos y lleoliad
+    .accesskey = L
+multiweek-legend = Golwg Wythnosau
+number-of-weeks-label =
+    .value = Nifer o wythnosau i'w dangos (gan gynnwys yr wythnos flaenorol):
+    .accesskey = N
+week-0-label =
+    .label = dim
+week-1-label =
+    .label = 1 wythnos
+week-2-label =
+    .label = 2 wythnos
+week-3-label =
+    .label = 3 wythnos
+week-4-label =
+    .label = 4 wythnos
+week-5-label =
+    .label = 5 wythnos
+week-6-label =
+    .label = 6 wythnos
+previous-weeks-label =
+    .value = Dangos yr wythnos flaenorol:
+    .accesskey = f
+todaypane-legend = Paen Heddiw
+# Note: "Upcoming" is the name of a section and the translation must match the
+# translation of that section name (calendar.upcoming.button.label). Also,
+# it should be upper case (as a proper name) if the target language permits.
+soon-label =
+    .value = Mae'r adran Nesaf yn dangos:
+    .accesskey = N
+event-task-legend = Digwyddiadau a Thasgau
+default-length-label =
+    .value = Hyd Digwyddiad a Tasg Rhagosodedig:
+    .accesskey = D
+task-start-label =
+    .value = Dyddiad Cychwyn:
+task-start-1-label =
+    .label = Dim
+task-start-2-label =
+    .label = Cychwyn y Diwrnod
+task-start-3-label =
+    .label = Diwedd y Dydd
+task-start-4-label =
+    .label = Yfory
+task-start-5-label =
+    .label = Wythnos Nesaf
+task-start-6-label =
+    .label = Cymharol â'r Amser Cyfredol
+task-start-7-label =
+    .label = Cymharol â'r Cychwyn
+task-start-8-label =
+    .label = Cymharol â'r Awr Nesaf
+task-due-label =
+    .value = Dyddiad Gorffen:
+edit-intab-label =
+    .label = Golygu digwyddiadau a thasgau mewn tab yn lle mewn ffenestr deialog.
+    .accesskey = G
+accessibility-legend = Hygyrchedd
+accessibility-colors-label =
+    .label = Mireinio lliwiau ar gyfer hygyrchedd
+    .accesskey = M
+reminder-legend = Pan fydd Disgwyl Atgoffwr:
+reminder-play-checkbox =
+    .label = Canu nodyn
+    .accesskey = n
+reminder-play-alarm-button =
+    .label = Chwarae
+    .accesskey = C
+reminder-default-sound-label =
+    .label = Defnyddio'r sain rhagosodedig
+    .accesskey = s
+reminder-custom-sound-label =
+    .label = Defnyddio'r ffeil sain ganlynol
+    .accesskey = D
+reminder-browse-sound-label =
+    .label = Pori…
+    .accesskey = P
+reminder-dialog-label =
+    .label = Dangos y ddeialog atgoffa
+    .accesskey = d
+missed-reminder-label =
+    .label = Dangos atgoffwyr wedi'u colli ar gyfer calendrau ysgrifenadwy
+    .accesskey = n
+reminder-default-legend = Rhagosodiadau Atgoffwyr
+default-snooze-label =
+    .value = Hyd Cysgu Rhagosodedig:
+    .accesskey = C
+event-alarm-label =
+    .value = Gosodiadau atgoffa rhagosodedig ar gyfer digwyddiadau:
+    .accesskey = G
+alarm-on-label =
+    .label = Ymlaen
+alarm-off-label =
+    .label = Diffodd
+task-alarm-label =
+    .value = Gosodiadau atgoffa rhagosodedig ar gyfer tasgau:
+    .accesskey = o
+event-alarm-time-label =
+    .value = Amser rhagosodedig y bydd atgoffwr yn cael ei bennu cyn digwyddiad:
+    .accesskey = A
+task-alarm-time-label =
+    .value = Amser rhagosodedig y bydd atgoffwr yn cael ei bennu cyn tasg:
+    .accesskey = m
+category-new-label = Categori Newydd
+category-edit-label = Golygu Categori
+category-overwrite-title = Rhybudd: Enw dyblyg
+category-overwrite = Mae categori o'r enw yna yn bodoli eisoes. Hoffech chi ysgrifennu trosto?
+category-blank-warning = Rhaid rhoi enw categori.
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-alarms.properties b/l10n-cy/calendar/chrome/calendar/calendar-alarms.properties
new file mode 100644
index 0000000000..f0eeb3c2a4
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-alarms.properties
@@ -0,0 +1,39 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (reminderCustomTitle):
+# %1$S = unit, %2$S = reminderCustomOrigin
+# Example: "3 minutes" "before the task starts"
+reminderCustomTitle=%1$S %2$S
+reminderTitleAtStartEvent=Yr amser mae'r digwyddiad yn cychwyn
+reminderTitleAtStartTask=Yr amser mae'r dasg yn cychwyn
+reminderTitleAtEndEvent=Yr amser mae'r digwyddiad yn gorffen
+reminderTitleAtEndTask=Yr amser mae'r dasg yn gorffen
+
+# LOCALIZATION NOTE (reminderSnoozeOkA11y)
+# This string is not seen in the UI, it is read by screen readers when the user
+# focuses the "OK" button in the "Snooze for..." popup of the alarm dialog.
+# %1$S = any of unit*
+reminderSnoozeOkA11y=Atgoffwr cysgu %1$S
+
+reminderCustomOriginBeginBeforeEvent=cyn i'r digwyddiad gychwyn
+reminderCustomOriginBeginAfterEvent=ar ôl i'r digwyddiad gychwyn
+reminderCustomOriginEndBeforeEvent=cyn diwedd y digwyddiad
+reminderCustomOriginEndAfterEvent=ar ôl i'r digwyddiad orffen
+reminderCustomOriginBeginBeforeTask=cyn i'r dasg gychwyn
+reminderCustomOriginBeginAfterTask=ar ôl i'r dasg gychwyn
+reminderCustomOriginEndBeforeTask=cyn diwedd y dasg
+reminderCustomOriginEndAfterTask=ar ôl diwedd y dasg
+
+reminderErrorMaxCountReachedEvent=Mae gan y calendr gyfyngiad o #1 rhybudd i bob digwyddiad.;Mae gan y calendr gyfyngiad o #1 rhybudd i bob digwyddiad.
+reminderErrorMaxCountReachedTask=Mae gan y calendr gyfyngiad o #1 rhybudd i bob tasg.;Mae gan y calendr gyfyngiad o #1 rhybudd i bob tasg.
+
+# LOCALIZATION NOTE (reminderReadonlyNotification)
+# This notification will be presented in the alarm dialog if reminders for not
+# writable items/calenddars are displayed.
+# %1$S - localized value of calendar.alarm.snoozeallfor.label (defined in calendar.dtd)
+reminderReadonlyNotification=Dim ond cau ac nid cysgu y mae modd gwneud gydag atgoffwyr calendrau ar hyn o bryd - dim ond cysgu calendrau atgoffwyr ysgrifenadwy mae botwm '%1$S' yn ei wneud.
+# LOCALIZATION NOTE (reminderDisabledSnoozeButtonTooltip)
+# This tooltip is only displayed, if the button is disabled
+reminderDisabledSnoozeButtonTooltip=Nid yw cysgu atgoffwr yn cael ei gynnal ar gyfer calendrau darllen yn unig
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-event-dialog-attendees.properties b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog-attendees.properties
new file mode 100644
index 0000000000..a140be96c2
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog-attendees.properties
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+event.attendee.role.required = Mynychwr Angenrheidiol
+event.attendee.role.optional = Mynychwyr Dewisol
+event.attendee.role.nonparticipant = Nid Cyfrannogwr
+event.attendee.role.chair = Cadeirio
+event.attendee.role.unknown = Mynychwr Anhysbys (%1$S)
+
+event.attendee.usertype.individual = Unigolyn
+event.attendee.usertype.group = Grŵp
+event.attendee.usertype.resource = Adnodd
+event.attendee.usertype.room  = Ystafell
+event.attendee.usertype.unknown = Math Anhysbys (%1$S)
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.dtd b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.dtd
new file mode 100644
index 0000000000..889cb045e1
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.dtd
@@ -0,0 +1,428 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY event.title.label                  "Golygu Eitem" >
+
+<!ENTITY event.dialog.keepDurationButton.tooltip   "Cadw'r cyfnod wrth newid y dyddiad gorffen">
+<!ENTITY event.dialog.keepDurationButton.accesskey "K">
+
+<!ENTITY newevent.from.label                "Oddi wrth" >
+<!ENTITY newevent.to.label                  "At" >
+
+<!ENTITY newevent.status.label                    "Statws" >
+<!ENTITY newevent.status.accesskey                "S" >
+<!ENTITY newevent.eventStatus.none.label          "Heb ddiffinio" >
+<!ENTITY newevent.eventStatus.none.accesskey      "H" >
+<!ENTITY newevent.todoStatus.none.label           "Heb ddiffinio" >
+<!ENTITY newevent.eventStatus.cancelled.label     "Diddymwyd" >
+<!ENTITY newevent.eventStatus.cancelled.accesskey "D" >
+<!ENTITY newevent.todoStatus.cancelled.label      "Diddymwyd" >
+<!ENTITY newevent.status.tentative.label          "Amodol" >
+<!ENTITY newevent.status.tentative.accesskey      "A" >
+<!ENTITY newevent.status.confirmed.label          "Cadarnhawyd" >
+<!ENTITY newevent.status.confirmed.accesskey      "C" >
+<!ENTITY newevent.status.needsaction.label        "Angen Gweithredu" >
+<!ENTITY newevent.status.inprogress.label         "Ar Waith" >
+<!ENTITY newevent.status.completed.label          "Cwblhawyd" >
+
+<!-- The following entity is for New Task dialog only -->
+<!ENTITY newtodo.percentcomplete.label      "Cwblhau &#037;">
+
+<!-- LOCALIZATON NOTE(event.attendees.notify.label,event.attendees.notifyundisclosed.label,
+     event.attendees.disallowcounter.label)
+   - These three labels are displayed side by side in the event dialog, make sure
+   - they still fit in. -->
+<!ENTITY event.attendees.notify.label                "Hysbysu mynychwyr">
+<!ENTITY event.attendees.notify.accesskey            "m">
+<!ENTITY event.attendees.notifyundisclosed.label     "Gwahoddiad ar wahân i fynychwyr">
+<!ENTITY event.attendees.notifyundisclosed.accesskey "G">
+<!ENTITY event.attendees.notifyundisclosed.tooltip   "Mae'r dewis hwn yn anfon un e-bost gwahoddiad i bob mynychwr. Bydd y gwahoddiad yn cynnwys y mynychwr sy'n derbyn yn unig, fel nad yw manylion mynychwyr eraill yn cael eu datgelu.">
+<!ENTITY event.attendees.disallowcounter.label       "Gwahardd cyfrif">
+<!ENTITY event.attendees.disallowcounter.accesskey   "G">
+<!ENTITY event.attendees.disallowcounter.tooltip     "Dangos nad ydych yn derbyn cynigion croes">
+
+<!-- Keyboard Shortcuts -->
+<!ENTITY event.dialog.new.event.key2              "I">
+<!ENTITY event.dialog.new.task.key2               "D">
+<!ENTITY event.dialog.new.message.key2            "N">
+<!ENTITY event.dialog.close.key                   "W">
+<!ENTITY event.dialog.save.key                    "S">
+<!ENTITY event.dialog.saveandclose.key            "L">
+<!ENTITY event.dialog.print.key                   "P">
+<!ENTITY event.dialog.undo.key                    "Z">
+<!ENTITY event.dialog.redo.key                    "Y">
+<!ENTITY event.dialog.cut.key                     "X">
+<!ENTITY event.dialog.copy.key                    "C">
+<!ENTITY event.dialog.paste.key                   "V">
+<!ENTITY event.dialog.select.all.key              "A">
+
+<!-- Menubar -->
+<!ENTITY  event.menu.item.new.label                       "Newydd">
+<!ENTITY  event.menu.item.new.accesskey                   "N">
+<!ENTITY  event.menu.item.new.event.label                 "Digwyddiad">
+<!ENTITY  event.menu.item.new.event.accesskey             "D">
+<!ENTITY  event.menu.item.new.task.label                  "Tasg">
+<!ENTITY  event.menu.item.new.task.accesskey              "T">
+<!ENTITY  event.menu.item.new.message.label               "Neges">
+<!ENTITY  event.menu.item.new.message.accesskey           "N">
+<!ENTITY  event.menu.item.new.contact.label               "Cysylltiad Llyfr Cyfeiriadau">
+<!ENTITY  event.menu.item.new.contact.accesskey           "y">
+<!ENTITY  event.menu.item.close.label                     "Cau">
+<!ENTITY  event.menu.item.close.accesskey                 "C">
+
+<!-- LOCALIZATION NOTE
+   - event.menu.item.save.accesskey is used for the "Save" menu item
+   - when editing events/tasks in a dialog window.
+   - event.menu.item.save.tab.accesskey is used for the "Save" menu item
+   - when editing events/tasks in a tab. -->
+<!ENTITY  event.menu.item.save.label                      "Cadw">
+<!ENTITY  event.menu.item.save.accesskey                  "C">
+<!ENTITY  event.menu.item.save.tab.accesskey              "a">
+
+<!-- LOCALIZATION NOTE
+    - event.menu.item.saveandclose.accesskey is used for "Save and Close"
+    - menu item when editing events/tasks in a dialog window.
+    - event.menu.item.saveandclose.tab.accesskey is used for "Save and Close"
+    - when editing events/tasks in a tab. -->
+<!ENTITY  event.menu.item.saveandclose.label              "Cadw a Chau">
+<!ENTITY  event.menu.item.saveandclose.accesskey          "a">
+<!ENTITY  event.menu.item.saveandclose.tab.accesskey      "h">
+
+<!ENTITY  event.menu.item.delete.label                    "Dileu…">
+<!ENTITY  event.menu.item.delete.accesskey                "D">
+<!ENTITY  event.menu.item.page.setup.label                "Gosodiad Tudalen">
+<!ENTITY  event.menu.item.page.setup.accesskey            "T">
+<!ENTITY  event.menu.item.print.label                     "Argraffu">
+<!ENTITY  event.menu.item.print.accesskey                 "A">
+
+<!ENTITY  event.menu.edit.label                           "Golygu">
+<!ENTITY  event.menu.edit.accesskey                       "G">
+<!ENTITY  event.menu.edit.undo.label                      "Dadwneud">
+<!ENTITY  event.menu.edit.undo.accesskey                  "D">
+<!ENTITY  event.menu.edit.redo.label                      "Ailwneud">
+<!ENTITY  event.menu.edit.redo.accesskey                  "A">
+<!ENTITY  event.menu.edit.cut.label                       "Torri">
+<!ENTITY  event.menu.edit.cut.accesskey                   "T">
+<!ENTITY  event.menu.edit.copy.label                      "Copïo">
+<!ENTITY  event.menu.edit.copy.accesskey                  "C">
+<!ENTITY  event.menu.edit.paste.label                     "Gludo">
+<!ENTITY  event.menu.edit.paste.accesskey                 "G">
+<!ENTITY  event.menu.edit.select.all.label                "Dewis Popeth">
+<!ENTITY  event.menu.edit.select.all.accesskey            "P">
+
+<!ENTITY  event.menu.view.label                           "Golwg">
+<!ENTITY  event.menu.view.accesskey                       "G">
+<!ENTITY  event.menu.view.toolbars.label                  "Barrau Offer">
+<!ENTITY  event.menu.view.toolbars.accesskey              "B">
+<!ENTITY  event.menu.view.toolbars.event.label            "Bar Offer Digwyddiad">
+<!ENTITY  event.menu.view.toolbars.event.accesskey        "D">
+<!ENTITY  event.menu.view.toolbars.customize.label        "Cyfaddasu…">
+<!ENTITY  event.menu.view.toolbars.customize.accesskey    "y">
+<!ENTITY  event.menu.view.showlink.label                  "Dangos Dolen Gysylltiedig">
+<!ENTITY  event.menu.view.showlink.accesskey              "G">
+
+<!ENTITY  event.menu.options.label                            "Dewisiadau">
+<!ENTITY  event.menu.options.accesskey                        "D">
+<!ENTITY  event.menu.options.attendees.label                  "Gwahodd Mynychwyr…">
+<!ENTITY  event.menu.options.attendees.accesskey              "M">
+<!ENTITY  event.menu.options.timezone2.label                  "Dangos Cylchoedd Amser">
+<!ENTITY  event.menu.options.timezone2.accesskey              "D">
+<!ENTITY  event.menu.options.priority2.label                  "Blaenoriaeth">
+<!ENTITY  event.menu.options.priority2.accesskey              "B">
+<!ENTITY  event.menu.options.priority.notspecified.label      "Heb ddiffinio">
+<!ENTITY  event.menu.options.priority.notspecified.accesskey  "d">
+<!ENTITY  event.menu.options.priority.low.label               "Isel">
+<!ENTITY  event.menu.options.priority.low.accesskey           "I">
+<!ENTITY  event.menu.options.priority.normal.label            "Arferol">
+<!ENTITY  event.menu.options.priority.normal.accesskey        "A">
+<!ENTITY  event.menu.options.priority.high.label              "Uchel">
+<!ENTITY  event.menu.options.priority.high.accesskey          "U">
+<!ENTITY  event.menu.options.privacy.label                    "Preifatrwydd">
+<!ENTITY  event.menu.options.privacy.accesskey                "P">
+<!ENTITY  event.menu.options.privacy.public.label             "Digwyddiad Cyhoeddus">
+<!ENTITY  event.menu.options.privacy.public.accesskey         "C">
+<!ENTITY  event.menu.options.privacy.confidential.label       "Dangos Amser a Dyddiad yn Unig">
+<!ENTITY  event.menu.options.privacy.confidential.accesskey   "A">
+<!ENTITY  event.menu.options.privacy.private.label            "Digwyddiad Preifat">
+<!ENTITY  event.menu.options.privacy.private.accesskey        "P">
+<!ENTITY  event.menu.options.show.time.label                  "Dangos Amser fel">
+<!ENTITY  event.menu.options.show.time.accesskey              "A">
+<!ENTITY  event.menu.options.show.time.busy.label             "Prysur">
+<!ENTITY  event.menu.options.show.time.busy.accesskey         "P">
+<!ENTITY  event.menu.options.show.time.free.label             "Rhydd">
+<!ENTITY  event.menu.options.show.time.free.accesskey         "R">
+
+<!ENTITY event.invite.attendees.label                     "Gwahodd Mynychwyr…">
+<!ENTITY event.invite.attendees.accesskey                 "M">
+<!ENTITY event.email.attendees.label                      "Cyfansoddi E-bost i'r Holl Fynychwyr…">
+<!ENTITY event.email.attendees.accesskey                  "H">
+<!ENTITY event.email.tentative.attendees.label            "Cyfansoddi E-bost i Fynychwyr Ansicr…">
+<!ENTITY event.email.tentative.attendees.accesskey        "A">
+<!ENTITY event.remove.attendees.label2                    "Tynnu'r holl fynychwyr">
+<!ENTITY event.remove.attendees.accesskey                 "T">
+<!ENTITY event.remove.attendee.label                      "Tynnu mynychwr">
+<!ENTITY event.remove.attendee.accesskey                  "T">
+
+<!-- Toolbar -->
+<!ENTITY  event.toolbar.save.label2                       "Cadw">
+<!ENTITY  event.toolbar.saveandclose.label                "Cadw a Chau">
+<!ENTITY  event.toolbar.delete.label                      "Dileu">
+<!ENTITY  event.toolbar.attendees.label                   "Gwahodd Mynychwyr">
+<!ENTITY  event.toolbar.privacy.label                     "Preifatrwydd">
+
+<!ENTITY  event.toolbar.save.tooltip2                     "Cadw">
+<!ENTITY  event.toolbar.saveandclose.tooltip              "Cadw a Chau">
+<!ENTITY  event.toolbar.delete.tooltip                    "Dileu">
+<!ENTITY  event.toolbar.attendees.tooltip                 "Gwahodd Mynychwyr">
+<!ENTITY  event.toolbar.attachments.tooltip               "Ychwanegu Atodiad">
+<!ENTITY  event.toolbar.privacy.tooltip                   "Newid Preifatrwydd">
+<!ENTITY  event.toolbar.priority.tooltip                  "Newid Blaenoriaeth">
+<!ENTITY  event.toolbar.status.tooltip                    "Newid Statws">
+<!ENTITY  event.toolbar.freebusy.tooltip                  "Newid amser Rhydd/Prysur">
+
+<!-- Counter box -->
+<!-- LOCALIZATON NOTE(counter.button.*)
+   - This is only visible in the UI if you have received a counterproposal before and are going to
+   - reschedule the event from the imipbar in the email view. Clicking on the buttons will only
+   - populate the form fields in the dialog, there's no other immediate action on clicking like with
+   - the imip bar. Rescheduling will happen after clicking on save&close as usual. This screenshot
+   - illustrates how it might look like: https://bugzilla.mozilla.org/attachment.cgi?id=8810121 -->
+<!ENTITY counter.button.proposal.label                    "Gosod y cynnig">
+<!ENTITY counter.button.proposal.accesskey                "y">
+<!ENTITY counter.button.proposal.tooltip2                 "Bydd meysydd digwyddiad yn cael eu llanw gan ddefnyddio'r gwerthoedd o'r gwrth-gynnig, bydd dim ond ei gadw gyda neu heb newidiadau ac yn hysbysu'r holl fynychwyr ohono">
+<!ENTITY counter.button.original.label                    "Gosod y data gwreiddiol">
+<!ENTITY counter.button.original.accesskey                "g">
+<!ENTITY counter.button.original.tooltip2                 "Bydd y meysydd yn cael eu gosod i'r gwerthoedd o'r digwyddiad gwreiddiol, cyn i'r gwrth-gynnig gael ei wneud">
+
+<!-- Main page -->
+<!ENTITY event.title.textbox.label                        "Teitl:" >
+<!ENTITY event.title.textbox.accesskey                    "T">
+<!ENTITY event.location.label                             "Lleoliad:" >
+<!ENTITY event.location.accesskey                         "L">
+<!ENTITY event.categories.label                           "Categori:">
+<!ENTITY event.categories.accesskey                       "a">
+<!ENTITY event.categories.textbox.label                   "Ychwanegu categori newydd" >
+<!ENTITY event.calendar.label                             "Calendr:" >
+<!ENTITY event.calendar.accesskey                         "a">
+<!ENTITY event.attendees.label                            "Mynychwyr:" >
+<!ENTITY event.attendees.accesskey                        "y">
+<!ENTITY event.alldayevent.label                          "Digwyddiad drwy'r Dydd" >
+<!ENTITY event.alldayevent.accesskey                      "D">
+<!ENTITY event.from.label                                 "Cychwyn:" >
+<!ENTITY event.from.accesskey                             "C">
+<!ENTITY task.from.label                                  "Cychwyn:" >
+<!ENTITY task.from.accesskey                              "C">
+<!ENTITY event.to.label                                   "Gorffen:" >
+<!ENTITY event.to.accesskey                               "o">
+<!ENTITY task.to.label                                    "Erbyn Dyddiad:" >
+<!ENTITY task.to.accesskey                                "E">
+<!ENTITY task.status.label                                "Statws:" >
+<!ENTITY task.status.accesskey                            "S">
+<!ENTITY event.repeat.label                               "Ailadrodd:" >
+<!ENTITY event.repeat.accesskey                           "A">
+<!ENTITY event.until.label                                "Tan:">
+<!ENTITY event.until.accesskey                            "T">
+<!ENTITY event.reminder.label                             "Atgoffwr:" >
+<!ENTITY event.reminder.accesskey                         "t">
+<!ENTITY event.description.label                          "Disgrifiad:" >
+<!ENTITY event.description.accesskey                      "D">
+<!ENTITY event.attachments.label                          "Atodiadau:" >
+<!ENTITY event.attachments.accesskey                      "A" >
+<!ENTITY event.attachments.menubutton.label               "Atodi">
+<!ENTITY event.attachments.menubutton.accesskey           "A">
+<!ENTITY event.attachments.url.label                      "Tudalen gwe…">
+<!ENTITY event.attachments.url.accesskey                  "T">
+<!ENTITY event.attachments.popup.remove.label             "Tynnu" >
+<!ENTITY event.attachments.popup.remove.accesskey         "T" >
+<!ENTITY event.attachments.popup.open.label               "Agor" >
+<!ENTITY event.attachments.popup.open.accesskey           "A" >
+<!ENTITY event.attachments.popup.removeAll.label          "Tynnu Popeth" >
+<!ENTITY event.attachments.popup.removeAll.accesskey      "T" >
+<!ENTITY event.attachments.popup.attachPage.label         "Atodi Tudalen Gwe…" >
+<!ENTITY event.attachments.popup.attachPage.accesskey     "G" >
+<!ENTITY event.url.label                                  "Dolen Gysylltiedig:" >
+<!ENTITY event.priority2.label                            "Blaenoriaeth:">
+
+<!ENTITY event.reminder.none.label                        "Dim atgoffwr " >
+<!ENTITY event.reminder.0minutes.before.label             "0 munud cyn" >
+<!ENTITY event.reminder.5minutes.before.label             "5 munud cyn" >
+<!ENTITY event.reminder.15minutes.before.label            "15 munud cyn" >
+<!ENTITY event.reminder.30minutes.before.label            "30 munud cyn" >
+<!ENTITY event.reminder.1hour.before.label                "1 awr cyn" >
+<!ENTITY event.reminder.2hours.before.label               "2 awr cyn" >
+<!ENTITY event.reminder.12hours.before.label              "12 awr cyn" >
+<!ENTITY event.reminder.1day.before.label                 "1 diwrnod cyn" >
+<!ENTITY event.reminder.2days.before.label                "2 diwrnod cyn" >
+<!ENTITY event.reminder.1week.before.label                "1 wythnos cyn" >
+<!ENTITY event.reminder.custom.label                      "Cyfaddasu…" >
+
+<!ENTITY event.reminder.multiple.label                    "Atgoffwyr Niferus…" >
+
+<!ENTITY event.statusbarpanel.freebusy.label              "Amser:">
+<!ENTITY event.statusbarpanel.privacy.label               "Preifatrwydd:">
+
+<!-- Recurrence dialog -->
+<!ENTITY recurrence.title.label                         "Golygu'r ailadroddus">
+
+<!ENTITY event.repeat.does.not.repeat.label             "Nid yw'n ailadrodd">
+<!ENTITY event.repeat.daily.label                       "Dyddiol">
+<!ENTITY event.repeat.weekly.label                      "Wythnosol">
+<!ENTITY event.repeat.every.weekday.label               "Pob Diwrnod o'r Wythnos">
+<!ENTITY event.repeat.bi.weekly.label                   "Pythefnosol">
+<!ENTITY event.repeat.monthly.label                     "Misol">
+<!ENTITY event.repeat.yearly.label                      "Blynyddol">
+<!ENTITY event.repeat.custom.label                      "Cyfaddasu…">
+
+<!ENTITY event.recurrence.pattern.label                 "Patrwm ailddigwydd">
+<!ENTITY event.recurrence.occurs.label                  "Ailadrodd" >
+<!ENTITY event.recurrence.day.label                     "dyddiol" >
+<!ENTITY event.recurrence.week.label                    "wythnosol" >
+<!ENTITY event.recurrence.month.label                   "misol" >
+<!ENTITY event.recurrence.year.label                    "blynyddol" >
+
+<!ENTITY event.recurrence.pattern.every.label           "Pob" >
+<!ENTITY repeat.units.days.both                         "Dydd(iau)" >
+<!ENTITY event.recurrence.pattern.every.weekday.label   "Pob diwrnod wythnos" >
+
+<!ENTITY event.recurrence.pattern.weekly.every.label    "Pob" >
+<!ENTITY repeat.units.weeks.both                        "Wythnos(au)" >
+<!ENTITY event.recurrence.on.label                      "Ar:" >
+
+<!ENTITY event.recurrence.pattern.monthly.every.label   "Pob" >
+<!ENTITY repeat.units.months.both                       "Mis" >
+<!ENTITY event.recurrence.monthly.every.label           "Pob" >
+<!ENTITY event.recurrence.monthly.first.label           "Y Cyntaf">
+<!ENTITY event.recurrence.monthly.second.label          "Yr Ail">
+<!ENTITY event.recurrence.monthly.third.label           "Y Trydydd">
+<!ENTITY event.recurrence.monthly.fourth.label          "Y Pedwerydd">
+<!ENTITY event.recurrence.monthly.fifth.label           "Y Pumed">
+<!ENTITY event.recurrence.monthly.last.label            "Yr Olaf">
+<!ENTITY event.recurrence.pattern.monthly.week.1.label  "Sul" >
+<!ENTITY event.recurrence.pattern.monthly.week.2.label  "Llun" >
+<!ENTITY event.recurrence.pattern.monthly.week.3.label  "Mawrth" >
+<!ENTITY event.recurrence.pattern.monthly.week.4.label  "Mercher" >
+<!ENTITY event.recurrence.pattern.monthly.week.5.label  "Iau" >
+<!ENTITY event.recurrence.pattern.monthly.week.6.label  "Gwener" >
+<!ENTITY event.recurrence.pattern.monthly.week.7.label  "Sadwrn" >
+<!ENTITY event.recurrence.repeat.dayofmonth.label       "Diwrnod y mis">
+<!ENTITY event.recurrence.repeat.recur.label            "Ail ddigwydd ar ddydd(iau)">
+
+<!ENTITY event.recurrence.every.label                        "Pob:" >
+<!ENTITY repeat.units.years.both                             "Blwyddyn" >
+<!ENTITY event.recurrence.pattern.yearly.every.month.label   "Pob" >
+
+<!-- LOCALIZATON NOTE
+     Some languages use a preposition when describing dates:
+     Portuguese: 6 de Setembro
+     English: 6 [of] September
+     event.recurrence.pattern.yearly.of.label is "of" in
+     Edit recurrence window -> Recurrence pattern -> Repeat yearly
+-->
+<!ENTITY event.recurrence.pattern.yearly.of.label            "" >
+
+<!ENTITY event.recurrence.pattern.yearly.month.1.label       "Ionawr" >
+<!ENTITY event.recurrence.pattern.yearly.month.2.label       "Chwefror" >
+<!ENTITY event.recurrence.pattern.yearly.month.3.label       "Mawrth" >
+<!ENTITY event.recurrence.pattern.yearly.month.4.label       "Ebrill" >
+<!ENTITY event.recurrence.pattern.yearly.month.5.label       "Mai" >
+<!ENTITY event.recurrence.pattern.yearly.month.6.label       "Mehefin" >
+<!ENTITY event.recurrence.pattern.yearly.month.7.label       "Gorffennaf" >
+<!ENTITY event.recurrence.pattern.yearly.month.8.label       "Awst" >
+<!ENTITY event.recurrence.pattern.yearly.month.9.label       "Medi" >
+<!ENTITY event.recurrence.pattern.yearly.month.10.label      "Hydref" >
+<!ENTITY event.recurrence.pattern.yearly.month.11.label      "Tachwedd" >
+<!ENTITY event.recurrence.pattern.yearly.month.12.label      "Rhagfyr" >
+<!ENTITY event.recurrence.yearly.every.label                 "Pob">
+<!ENTITY event.recurrence.yearly.first.label                 "Y Cyntaf">
+<!ENTITY event.recurrence.yearly.second.label                "Yr Ail">
+<!ENTITY event.recurrence.yearly.third.label                 "Y Trydydd">
+<!ENTITY event.recurrence.yearly.fourth.label                "Y Pedwerydd">
+<!ENTITY event.recurrence.yearly.fifth.label                 "Y Pumed">
+<!ENTITY event.recurrence.yearly.last.label                  "Yr Olaf">
+<!ENTITY event.recurrence.pattern.yearly.week.1.label        "Sul" >
+<!ENTITY event.recurrence.pattern.yearly.week.2.label        "Llun" >
+<!ENTITY event.recurrence.pattern.yearly.week.3.label        "Mawrth" >
+<!ENTITY event.recurrence.pattern.yearly.week.4.label        "Mercher" >
+<!ENTITY event.recurrence.pattern.yearly.week.5.label        "Iau" >
+<!ENTITY event.recurrence.pattern.yearly.week.6.label        "Gwener" >
+<!ENTITY event.recurrence.pattern.yearly.week.7.label        "Sadwrn" >
+<!ENTITY event.recurrence.pattern.yearly.day.label           "diwrnod" >
+<!ENTITY event.recurrence.of.label                           "o" >
+<!ENTITY event.recurrence.pattern.yearly.month2.1.label      "Ionawr" >
+<!ENTITY event.recurrence.pattern.yearly.month2.2.label      "Chwefror" >
+<!ENTITY event.recurrence.pattern.yearly.month2.3.label      "Mawrth" >
+<!ENTITY event.recurrence.pattern.yearly.month2.4.label      "Ebrill" >
+<!ENTITY event.recurrence.pattern.yearly.month2.5.label      "Mai" >
+<!ENTITY event.recurrence.pattern.yearly.month2.6.label      "Mehefin" >
+<!ENTITY event.recurrence.pattern.yearly.month2.7.label      "Gorffennaf" >
+<!ENTITY event.recurrence.pattern.yearly.month2.8.label      "Awst" >
+<!ENTITY event.recurrence.pattern.yearly.month2.9.label      "Medi" >
+<!ENTITY event.recurrence.pattern.yearly.month2.10.label     "Hydref" >
+<!ENTITY event.recurrence.pattern.yearly.month2.11.label     "Tachwedd" >
+<!ENTITY event.recurrence.pattern.yearly.month2.12.label     "Rhagfyr" >
+
+<!ENTITY event.recurrence.range.label                   "Ystod ailadrodd">
+<!ENTITY event.recurrence.forever.label                 "Dim dyddiad gorffen" >
+<!ENTITY event.recurrence.repeat.for.label              "Creu" >
+<!ENTITY event.recurrence.appointments.label            "apwyntiad" >
+<!ENTITY event.repeat.until.label                       "Ailadrodd tan" >
+<!ENTITY event.recurrence.preview.label                 "Rhagolwg">
+
+<!-- Attendees dialog -->
+<!ENTITY invite.title.label                     "Gwahodd Mynychwyr">
+<!ENTITY event.organizer.label                  "Trefnydd">
+<!ENTITY event.freebusy.suggest.slot            "Cynnig cyfnod trefnu:">
+<!ENTITY event.freebusy.button.next.slot        "Cyfnod nesaf">
+<!ENTITY event.freebusy.button.previous.slot    "Cyfnod blaenorol">
+<!ENTITY event.freebusy.zoom                    "Chwyddo:">
+<!ENTITY event.freebusy.legend.free             "Rhydd" >
+<!ENTITY event.freebusy.legend.busy             "Prysur" >
+<!ENTITY event.freebusy.legend.busy_tentative   "Amodol" >
+<!ENTITY event.freebusy.legend.busy_unavailable "Allan o'r Swyddfa" >
+<!ENTITY event.freebusy.legend.unknown          "Dim Gwybodaeth" >
+<!ENTITY event.attendee.role.required           "Mynychwr Angenrheidiol">
+<!ENTITY event.attendee.role.optional           "Mynychwr Dewisol">
+<!ENTITY event.attendee.role.chair              "Cadeirio">
+<!ENTITY event.attendee.role.nonparticipant     "Nid Cyfrannogwr">
+<!ENTITY event.attendee.usertype.individual     "Unigolyn">
+<!ENTITY event.attendee.usertype.group          "Grŵp">
+<!ENTITY event.attendee.usertype.resource       "Adnodd">
+<!ENTITY event.attendee.usertype.room           "Ystafell">
+<!ENTITY event.attendee.usertype.unknown        "Anhysbys">
+
+<!-- Timezone dialog -->
+<!ENTITY timezone.title.label            "Nodwch y Cylch Amser">
+<!ENTITY event.timezone.custom.label     "Rhagor o Gylchoedd Amser…">
+
+<!-- Read-Only dialog -->
+<!ENTITY read.only.general.label         "Cyffredinol">
+<!ENTITY read.only.title.label           "Teitl:">
+<!ENTITY read.only.calendar.label        "Calendr:">
+<!ENTITY read.only.event.start.label     "Dyddiad Cychwyn:">
+<!ENTITY read.only.task.start.label      "Dyddiad Cychwyn:">
+<!ENTITY read.only.event.end.label       "Dyddiad Gorffen:">
+<!ENTITY read.only.task.due.label        "Dyddiad Gorffen:">
+<!ENTITY read.only.repeat.label          "Ailadrodd:">
+<!ENTITY read.only.location.label        "Lleoliad:">
+<!ENTITY read.only.category.label        "Categori:">
+<!ENTITY read.only.organizer.label       "Trefnydd:">
+<!ENTITY read.only.reminder.label        "Atgoffwr:">
+<!ENTITY read.only.attachments.label     "Atodiadau:">
+<!ENTITY read.only.attendees.label       "Mynychwyr">
+<!ENTITY read.only.description.label     "Disgrifiad">
+<!ENTITY read.only.link.label            "Dolenni Perthnasol">
+
+<!-- Summary dialog -->
+<!ENTITY summary.dialog.saveclose.label         "Cadw a Chau">
+<!ENTITY summary.dialog.saveclose.tooltiptext   "Cadw'r newidiadau a chau'r ffenestr heb newid statws cyfrannu ac anfon ymateb">
+<!ENTITY summary.dialog.accept.label            "Derbyn">
+<!ENTITY summary.dialog.accept.tooltiptext      "Derbyn y gwahoddiad">
+<!ENTITY summary.dialog.tentative.label         "Amodol">
+<!ENTITY summary.dialog.tentative.tooltiptext   "Derbyn y gwahoddiad yn amodol">
+<!ENTITY summary.dialog.decline.label           "Gwrthod">
+<!ENTITY summary.dialog.decline.tooltiptext     "Gwrthod y gwahoddiad">
+<!ENTITY summary.dialog.dontsend.label          "Peidio anfon ymateb">
+<!ENTITY summary.dialog.dontsend.tooltiptext    "Newid eich statws cyfranogi heb anfon ymateb i'r trefnydd a chau'r ffenestr">
+<!ENTITY summary.dialog.send.label              "Anfon ymateb nawr">
+<!ENTITY summary.dialog.send.tooltiptext        "Anfon ymateb i'r trefnydd  a chau'r ffenestr">
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.properties b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.properties
new file mode 100644
index 0000000000..3076ad8828
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-event-dialog.properties
@@ -0,0 +1,541 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (dailyEveryNth):
+# Edit recurrence window -> Recurrence pattern -> Daily repeat rules
+# #1 - number
+# e.g. "every 4 days"
+dailyEveryNth=pob diwrnod;pob #1 diwrnod
+repeatDetailsRuleDaily4=pob diwrnod o'r wythnos
+
+# LOCALIZATION NOTE (weeklyNthOnNounclass...)
+# Edit recurrence window -> Recurrence pattern -> Weekly repeat rules
+# Translate these strings according to noun class/gender of weekday (%1$S)
+# set in 'repeadDetailsDay...Nounclass' strings.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add others strings with suffix 3, 4,... for others noun classes if your
+# language need them. In this case, corresponding strings must be added for
+# others rule strings with 'Nounclass...' suffix and corresponding values
+# "nounclass..." must be written in 'repeatDetailsDayxNounclass' strings.
+# %1$S - weekday (one or more)
+# #2 - week interval
+# e.g. "every 3 weeks on Tuesday, Wednesday and Thursday
+weeklyNthOnNounclass1=pob %1$S;pob #2 wythnos ar %1$S
+weeklyNthOnNounclass2=pob %1$S;pob #2 wythnos ar %1$S
+
+# LOCALIZATION NOTE (weeklyEveryNth):
+# Edit recurrence window -> Recurrence pattern -> Weekly repeat rules
+# #1 - interval
+# e.g. "every 5 weeks"
+weeklyEveryNth=pob wythnos;pob #1 wythnos
+
+# LOCALIZATION NOTE ('repeatDetailsDay...' and 'repeatDetailsDay...Nounclass'):
+# Week days names and week days noun classes (feminine/masculine grammatical
+# gender) for languages that need different localization when weekdays nouns
+# have different noun classes (genders).
+# For every weekday, in 'repeatDetailsDay...Nounclass' strings write:
+#   "nounclass1"     for languages with grammatical genders -> MASCULINE gender;
+#                    for languages with noun classes -> a noun class;
+#                    for languages without noun classes or grammatical gender.
+#
+#   "nounclass2"     for languages with grammatical genders -> FEMININE gender;
+#                    for languages with noun classes -> a different noun class.
+#
+#   "nounclass3", "nounclass4" and so on for languages that need more than two
+#                    noun classes for weekdays. In this case add corresponding
+#                    rule string with "Nounclass..." suffix and ordinal string
+#                    "repeatOrdinalxNounclass..."
+# Will be used rule strings with "Nounclass..." suffix corresponding to the
+# following strings if there is a weekday in the rule string.
+repeatDetailsDay1=Dydd Sul
+repeatDetailsDay1Nounclass=nounclass1
+repeatDetailsDay2=Dydd Llun
+repeatDetailsDay2Nounclass=nounclass1
+repeatDetailsDay3=Dydd Mawrth
+repeatDetailsDay3Nounclass=nounclass1
+repeatDetailsDay4=Dydd Mercher
+repeatDetailsDay4Nounclass=nounclass1
+repeatDetailsDay5=Dydd Iau
+repeatDetailsDay5Nounclass=nounclass1
+repeatDetailsDay6=Dydd Gwener
+repeatDetailsDay6Nounclass=nounclass1
+repeatDetailsDay7=Dydd Sadwrn
+repeatDetailsDay7Nounclass=nounclass1
+
+# LOCALIZATION NOTE (repeatDetailsAnd)
+# Used to show a number of weekdays in a list
+# i.e. "Sunday, Monday, Tuesday " + and + " Wednesday"
+repeatDetailsAnd=a
+
+# LOCALIZATION NOTE (monthlyRuleNthOfEveryNounclass...):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# Translate these strings according to noun class/gender of weekday (%2$S)
+# set in 'repeadDetailsDay...Nounclass' strings.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add others strings with suffix 3, 4,... for others noun classes if your
+# language need them. In this case, corresponding strings must be added for
+# others rule strings with 'Nounclass...' suffix and corresponding values
+# "nounclass..." must be written in 'repeatDetailsDayxNounclass' strings.
+# %1$S - list of weekdays with ordinal, article and noun class/gender
+#        (ordinal and weekday of every element in the list follow the order
+#         and the rule of ordinalWeekdayOrder string)
+# #2 - interval
+# e.g. "the first Monday and the last Friday of every 3 months"
+monthlyRuleNthOfEveryNounclass1=%1$S o bob mis;%1$S o bob #2 mis
+monthlyRuleNthOfEveryNounclass2=%1$S o bob mis;%1$S o bob #2 mis
+
+# LOCALIZATION NOTE (ordinalWeekdayOrder):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# This string allows to change the order of the elements "ordinal" and
+# "weekday" (or to insert a word between them) for the argument %1$S of the
+# string monthlyRuleNthOfEveryNounclass...
+# Without changing this string, the order is that one required from most
+# languages: ordinal + weekday (e.g. "'the first' 'Monday' of every 2 months").
+# %1$S - ordinal with article
+# %2$S - weekday noun
+# e.g. "'the first' 'Monday'"
+# DONT_TRANSLATE: Make sure there are no extra words in this property, just variables.
+ordinalWeekdayOrder=%1$S %2$S
+
+# LOCALIZATION NOTE (monthlyEveryOfEveryNounclass...):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# Translate these strings according to noun class/gender of weekday (%1$S)
+# set in 'repeadDetailsDay...Nounclass' strings.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add others strings with suffix 3, 4,... for others noun classes if your
+# language need them. In this case, corresponding strings must be added for
+# others rule strings with 'Nounclass...' suffix and corresponding values
+# "nounclass..." must be written in 'repeatDetailsDayxNounclass' strings.
+# %1$S - list of single weekdays and/or weekdays with ordinal, article and
+#        noun class/gender when rule contains also specific day in the month
+# #2 - interval
+# e.g. "every Monday, Tuesday and the second Sunday of every month"
+monthlyEveryOfEveryNounclass1=bob %1$S o bob mis;bob %1$S o bob #2 mis
+monthlyEveryOfEveryNounclass2=bob %1$S o bob mis;bob %1$S o bob #2 mis
+
+# LOCALIZATION NOTE (monthlyDaysOfNth_day):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# %1$S - day of month or a sequence of days of month, possibly followed by an ordinal symbol
+#        (depending on the string dayOrdinalSymbol in dateFormat.properties) separated with commas;
+# e.g. "days 3, 6 and 9" or "days 3rd, 6th and 9th"
+monthlyDaysOfNth_day=diwrnod %1$S;diwrnod %1$S
+
+# LOCALIZATION NOTE (monthlyDaysOfNth):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# %1$S - it's the string monthlyDaysOfNth_day: day of month or a sequence of days
+#        of month, possibly followed by an ordinal symbol, separated with commas;
+# #2   - monthly interval
+# e.g. "days 3, 6, 9 and 12 of every 3 months"
+monthlyDaysOfNth=%1$S o bob mis;%1$S o bob #2 mis
+
+# LOCALIZATION NOTE (monthlyLastDayOfNth):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# %1$S - day of month
+# #2 - month interval
+# e.g. "the last day of every 3 months"
+monthlyLastDayOfNth=diwrnod olaf y mis; diwrnod olaf pob #1 mis
+
+# LOCALIZATION NOTE (monthlyEveryDayOfNth):
+# Edit recurrence window -> Recurrence pattern -> Monthly repeat rules
+# #2 - month interval
+# e.g. "every day of the month every 4 months"
+monthlyEveryDayOfNth=pob diwrnod o bob mis;pob diwrnod o'r mis bob #2 mis
+
+# LOCALIZATION NOTE (repeatOrdinal...Nounclass...):
+# Ordinal numbers nouns for every noun class (grammatical genders) of weekdays
+# considered in 'repeatDetailsDayxNounclass' strings. For languages that need
+# localization according to genders or noun classes.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add 'repeatOrdinal...Nounclass' strings with suffix 3, 4 and so on for
+# languages with more than two noun classes for weekdays. In this case
+# must be added corresponding rule strings with 'Nounclass...' suffix and
+# corresponding values "nounclass..." must be written in
+# 'repeatDetailsDayxNounclass' strings.
+repeatOrdinal1Nounclass1=y cyntaf
+repeatOrdinal2Nounclass1=yr ail
+repeatOrdinal3Nounclass1=y trydydd
+repeatOrdinal4Nounclass1=y pedwerydd
+repeatOrdinal5Nounclass1=y pumed
+repeatOrdinal-1Nounclass1=yr olaf
+repeatOrdinal1Nounclass2=y cyntaf
+repeatOrdinal2Nounclass2=yr ail
+repeatOrdinal3Nounclass2=y trydydd
+repeatOrdinal4Nounclass2=y pedwerydd
+repeatOrdinal5Nounclass2=y pumed
+repeatOrdinal-1Nounclass2=yr olaf
+
+# LOCALIZATION NOTE (yearlyNthOn):
+# Edit recurrence window -> Recurrence pattern -> Yearly repeat rules
+# %1$S - month name
+# %2$S - day of month possibly followed by an ordinal symbol (depending on the string
+#           dayOrdinalSymbol in dateFormat.properties)
+# #3   - yearly interval
+# e.g. "every 3 years on December 14"
+#      "every 2 years on December 8th"
+yearlyNthOn=pob %1$S %2$S;pob #3 blwyddyn ar %1$S %2$S
+
+# LOCALIZATION NOTE (yearlyNthOnNthOfNounclass...):
+# Edit recurrence window -> Recurrence pattern -> Yearly repeat rules
+# Translate these strings according to noun class/gender of weekday (%2$S)
+# set in 'repeadDetailsDay...Nounclass' strings.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add others strings with suffix 3, 4,... for others noun classes if your
+# language need them. In this case, corresponding strings must be added for
+# others rule strings with 'Nounclass...' suffix and corresponding values
+# "nounclass..." must be written in 'repeatDetailsDayxNounclass' strings.
+# %1$S - ordinal with article and noun class/gender corresponding to weekday
+# %2$S - weekday
+# %3$S - month
+# #4 - yearly interval
+# e.g. "the second Monday of every March"
+# e.g  "every 3 years the second Monday of March"
+yearlyNthOnNthOfNounclass1=%1$S %2$S o bob %3$S;pob #4 blwyddyn ar %1$S %2$S o %3$S
+yearlyNthOnNthOfNounclass2=%1$S %2$S o bob %3$S;pob #4 blwyddyn ar %1$S %2$S o %3$S
+
+# LOCALIZATION NOTE (yearlyOnEveryNthOfNthNounclass...):
+# Edit recurrence window -> Recurrence pattern -> Yearly repeat rules
+# Translate these strings according to noun class/gender of weekday (%1$S)
+# set in 'repeadDetailsDay...Nounclass' strings.
+# Nounclass1 <-> Masculine gender; Nounclass2 <-> Feminine gender.
+# Add others strings with suffix 3, 4,... for others noun classes if your
+# language need them. In this case, corresponding strings must be added for
+# others rule strings with 'Nounclass...' suffix and corresponding values
+# "nounclass..." must be written in 'repeatDetailsDayxNounclass' strings.
+# %1$S - weekday
+# %2$S - month
+# #3 - yearly interval
+# e.g. "every Thursday of March"
+# e.g  "every 3 years on every Thursday of March"
+yearlyOnEveryNthOfNthNounclass1=pob %1$S o %2$S;pob #3 blwyddyn ar bob %1$S of %2$S
+yearlyOnEveryNthOfNthNounclass2=pob %1$S o %2$S;pob #3 blwyddyn ar bob %1$S of %2$S
+
+#LOCALIZATION NOTE (yearlyEveryDayOf):
+# Edit recurrence window -> Recurrence pattern -> Yearly repeat rules
+# This string describes part of a yearly rule which includes every day of a month.
+# %1$S - month
+# #2   - yearly interval
+# e.g. "every day of December"
+# e.g. "every 3 years every day of December"
+yearlyEveryDayOf=pob diwrnod o %1$S;pob #2 blwyddyn pob diwrnod yn %1$S
+
+repeatDetailsMonth1=Ionawr
+repeatDetailsMonth2=Chwefror
+repeatDetailsMonth3=Mawrth
+repeatDetailsMonth4=Ebrill
+repeatDetailsMonth5=Mai
+repeatDetailsMonth6=Mehefin
+repeatDetailsMonth7=Gorffennaf
+repeatDetailsMonth8=Awst
+repeatDetailsMonth9=Medi
+repeatDetailsMonth10=Hydref
+repeatDetailsMonth11=Tachwedd
+repeatDetailsMonth12=Rhagfyr
+
+# LOCALIZATION NOTE (repeatCount):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# %3$S - event start time (e.g. hh:mm (PM/AM))
+# %4$S - event end time (e.g. hh:mm (PM/AM))
+# #5 - event occurence times: number
+# e.g. with monthlyRuleNthOfEvery:
+# "Occurs the first Sunday of every 3 month
+#  only on 1/1/2009"
+#  from 5:00 PM to 6:00 PM"
+# "Occurs the first Sunday of every 3 month
+#  effective 1/1/2009 for 5 times
+#  from 5:00 PM to 6:00 PM"
+repeatCount=Yn digwydd %1$S\no %2$S am #5 gwaith\no %3$S hyd %4$S.;Digwydd %1$S\no %2$S am #5 gwaith\no %3$S hyd %4$S.
+
+# LOCALIZATION NOTE (repeatCountAllDay):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# #3 - event occurence times: number
+# e.g. with monthlyRuleNthOfEvery:
+# "Occurs the first Sunday of every 3 month
+#  only on 1/1/2009"
+# "Occurs the first Sunday of every 3 month
+#  effective 1/1/2009 for 5 times"
+repeatCountAllDay=Yn digwydd %1$S\no %2$S am #3 gwaith.;Digwydd %1$S\no %2$S am #3 gwaith.
+
+# LOCALIZATION NOTE (repeatDetailsUntil):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# %3$S - event end date (e.g. mm/gg/yyyy)
+# %4$S - event start time (e.g. hh:mm (PM/AM))
+# %5$S - event end time (e.g. hh:mm (PM/AM))
+# e.g. with weeklyNthOn:
+# "Occurs every 2 weeks on Sunday and Friday
+#  effective 1/1/2009 until 1/1/2010
+#  from 5:00 PM to 6:00 PM"
+repeatDetailsUntil=Yn digwydd %1$S\no %2$S tan %3$S\no %4$S hyd %5$S.
+
+# LOCALIZATION NOTE (repeatDetailsUntilAllDay):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# %3$S - event end date (e.g. mm/gg/yyyy)
+# e.g. with monthlyDaysOfNth and all day event:
+# "Occurs day 3 of every 5 month
+#  effective 1/1/2009 until 1/1/2010"
+repeatDetailsUntilAllDay=Yn digwydd %1$S\no %2$S tan %3$S.
+
+# LOCALIZATION NOTE (repeatDetailsInfinite):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# %3$S - event start time (e.g. hh:mm (PM/AM))
+# %4$S - event end time (e.g. hh:mm (PM/AM))
+# e.g. with monthlyDaysOfNth:
+# "Occurs day 3 of every 5 month
+#  effective 1/1/2009
+#  from 5:00 PM to 6:00 PM"
+repeatDetailsInfinite=Yn digwydd %1$S\nhyd %2$S\no %3$S tan %4$S.
+
+# LOCALIZATION NOTE (repeatDetailsInfiniteAllDay):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# %1%$ - A rule string (see above). This is the first line of the link
+# %2%$ - event start date (e.g. mm/gg/yyyy)
+# e.g. with monthlyDaysOfNth and all day event:
+# "Occurs day 3 of every 5 month
+#  effective 1/1/2009"
+repeatDetailsInfiniteAllDay=Yn digwydd %1$S\no %2$S.
+
+# LOCALIZATION NOTE (monthlyLastDay):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# A monthly rule with one or more days of the month (monthlyDaysOfNth) and the
+# string "the last day" of the month.
+# e.g.: "Occurs day 15, 20, 25 and the last day of every 3 months"
+monthlyLastDay=y diwrnod olaf
+
+# LOCALIZATION NOTE (ruleTooComplex):
+# This string is shown in the repeat details area if our code can't handle the
+# complexity of the recurrence rule yet.
+ruleTooComplex=Cliciwch yma am fanylion
+
+# LOCALIZATION NOTE (ruleTooComplexSummary):
+# This string is shown in the event summary dialog if our code can't handle the
+# complexity of the recurrence rule yet.
+ruleTooComplexSummary=Manylion ailadrodd yn anhysbys
+
+# differences between the dialog for an Event or a Task
+newEvent=Digwyddiad Newydd
+newTask=Tasg Newydd
+itemMenuLabelEvent=Digwyddiad
+itemMenuAccesskeyEvent2=D
+itemMenuLabelTask=Tasg
+itemMenuAccesskeyTask2=T
+
+emailSubjectReply=Ynghylch: %1$S
+
+# Link Location Dialog
+specifyLinkLocation=Pennwch leoliad y ddolen
+enterLinkLocation=Rhowch leoliad tudalen gwe neu ddogfen.
+
+summaryDueTaskLabel=Erbyn:
+
+# Attach File Dialog
+attachViaFilelink=Ffeilio gan ddefnyddio %1$S
+selectAFile=Dewiswch ffeil(iau) i'w hatodi
+removeCalendarsTitle=Tynnu Atodiad
+
+# LOCALIZATION NOTE (removeAttachmentsText): Semi-colon list of plural forms for
+# prompting attachment removal.
+# See http://developer.mozilla.org/en/Localization_and_Plurals
+removeAttachmentsText=Peidio tynnu atodiadau?;Ydych chi wir eisiau tynnu #1 atodiad?;Ydych chi wir eisiau tynnu #1 o atodiadau?;Ydych chi wir eisiau tynnu #1 o atodiadau?;Ydych chi wir eisiau tynnu #1 o atodiadau?;Ydych chi wir eisiau tynnu #1 o atodiadau?
+
+# Recurrence Dialog Widget Order
+# LOCALIZATION NOTE: You can change the order of below params
+# Edit recurrence window -> Recurrence pattern -> Repeat monthly
+# %1$S - ordinal with article, %2$S - weekday
+# e.g. "the First Saturday"
+# DONT_TRANSLATE: Make sure there are no extra words in this property, just variables.
+monthlyOrder=%1$S %2$S
+
+# Edit recurrence window -> Recurrence pattern -> Repeat yearly
+# %1$S - day of month, %2$S - of, %3$S - month
+# e.g. "6 [of] September"
+# If you don't need %2$S in your locale - please put this on the third place.
+# DONT_TRANSLATE: Make sure there are no extra words in this property, just variables.
+yearlyOrder=%1$S %3$S %2$S
+
+# Edit recurrence window -> Recurrence pattern -> Repeat yearly
+# %1$S - ordinal with article, %2$S - weekday, %3$S  - of, %4$S - month
+# e.g. "the First Saturday of September"
+# If you don't need %3$S in your locale - please put this on the third place.
+# DONT_TRANSLATE: Make sure there are no extra words in this property, just variables.
+yearlyOrder2=%1$S %2$S %3$S %4$S
+
+# LOCALIZATION NOTE (pluralForWeekdays):
+# This string allows to set the use of weekdays nouns in plural form for
+# languages that need them in sentences like "every Monday" or "every Sunday
+# of March" etc.
+# Rule strings involved by this setting are:
+# - weeklyNthOn   (only the first part) e.g. "every Sunday"
+# - monthlyEveryOfEvery
+#     e.g. "every Monday of every month;every Monday every 2 months"
+# - yearlyOnEveryNthOfNth
+#     e.g. "every Friday of March;every 2 years on every Friday of March"
+# In your local write:
+#  "true"    if sentences like those above need weekday in plural form;
+#  "false"   if sentences like those above don't need weekday in plural form;
+pluralForWeekdays=false
+
+# LOCALIZATION NOTE (repeatDetailsDayxxxPlural):
+# Edit recurrence window -> Recurrence details link on Event/Task dialog window
+# Weekdays in plural form used inside sentences like "every Monday" or
+# "every Sunday of May" etc. for languages that need them.
+# These plurals will be used inside the following rule strings only if string
+# 'pluralForWeekdays' (see above) is set to "true":
+# - weeklyNthOn   (only the first part) e.g. "every Sunday"
+# - monthlyEveryOfEvery
+#     e.g. "every Monday of every month;every Monday every 2 months"
+# - yearlyOnEveryNthOfNth
+#     e.g. "every Friday of March;every 2 years on every Friday of March"
+repeatDetailsDay1Plural=Dydd Sul
+repeatDetailsDay2Plural=Dydd Llun
+repeatDetailsDay3Plural=Dydd Mawrth
+repeatDetailsDay4Plural=Dydd Mercher
+repeatDetailsDay5Plural=Dydd Iau
+repeatDetailsDay6Plural=Dydd Gwener
+repeatDetailsDay7Plural=Dydd Sadwrn
+
+# LOCALIZATION NOTE (eventRecurrenceForeverLabel):
+# Edit/New Event dialog -> datepicker that sets the until date.
+# For recurring rules that repeat forever, this labels appears in the
+# datepicker, below the minimonth, as an option for the until date.
+eventRecurrenceForeverLabel=Am Byth
+
+# LOCALIZATION NOTE (eventRecurrenceMonthlyLastDayLabel):
+# Edit dialog recurrence -> Monthly Recurrence pattern -> Monthly daypicker
+# The label on the monthly daypicker's last button that allows to select
+# the last day of the month inside a BYMONTHDAY rule.
+eventRecurrenceMonthlyLastDayLabel=Y diwrnod olaf
+
+# LOCALIZATION NOTE (counterSummaryAccepted) - this is only visible when opening the dialog from the
+# email summary view after receiving a counter message
+# %1$S - the name or email address of the replying attendee
+counterSummaryAccepted=Mae 0%1$S wedi derbyn y gwahoddiad, ond wedi cyflwyno gwrthgynnig:
+
+# LOCALIZATION NOTE (counterSummaryDeclined) - this is only visible when opening the dialog from the
+# email summary view after receiving a counter message
+# %1$S - the name or email address of the replying attendee
+counterSummaryDeclined=Mae %1$S wedi gwrthod y gwahoddiad, ond wedi cynnig cyflwyno croes:
+
+# LOCALIZATION NOTE (counterSummaryDelegated) - this is only visible when opening the dialog from the
+# email summary view after receiving a counter message
+# %1$S - the name or email address of the replying attendee
+counterSummaryDelegated=%1$S wedi dirprwyo'r gwahoddiad, ond wedi cyflwyno gwrthgynnig:
+
+# LOCALIZATION NOTE (counterSummaryNeedsAction) - this is only visible when opening the dialog from the
+# email summary view after receiving a counter message
+# %1$S - the name or email address of the replying attendee
+counterSummaryNeedsAction=Nid yw %1$S wedi p'un ai i gymryd rhan ac wedi ac wedi cyflwyno gwrthgynnig:
+
+# LOCALIZATION NOTE (counterSummaryTentative) - this is only visible when opening the dialog from the
+# email summary view after receiving a counter message
+# %1$S - the name or email address of the replying attendee
+counterSummaryTentative=Mae 0%1$S wedi derbyn y gwahoddiad yn amodol, ond wedi cyflwyno gwrthgynnig:
+
+# LOCALIZATION NOTE (counterOnPreviousVersionNotification) - this is only visible when opening the
+# dialog from the email summary view after receiving a counter message
+counterOnPreviousVersionNotification=Mae hyn yn gynnig croes i'r fersiwn blaenorol o'r digwyddiad hwn.
+
+# LOCALIZATION NOTE (counterOnCounterDisallowedNotification) - this is only visible when opening the
+# dialog from the email summary view after receiving a counter message
+counterOnCounterDisallowedNotification=Rydych wedi atal cynigion croes wrth anfon y gwahoddiad.
+
+# LOCALIZATION NOTE (eventAccepted) - this will be displayed as notification
+# in the summary dialog if the user has accepted the event invitation
+eventAccepted=Rydych wedi derbyn y gwahoddiad
+
+# LOCALIZATION NOTE (eventTentative) - this will be displayed as notification
+# in the summary dialog if the user has accepted the event invitation tentatively
+eventTentative=Rydych wedi derbyn y gwahoddiad yn amodol
+
+# LOCALIZATION NOTE (eventDeclined) - this will be displayed as notification
+# in the summary dialog if the user has declined the event invitation
+eventDeclined=Rydych wedi gwrthod y gwahoddiad
+
+# LOCALIZATION NOTE (eventDelegated) - this will be displayed as notification
+# in the summary dialog if the user has delegated his/her participation to one
+# or more other participants (without attending / working on it his/herself)
+eventDelegated=Rydych wedi dirprwyo'r gwahoddiad
+
+# LOCALIZATION NOTE (eventNeedsAction) - this will be displayed as notification
+# in the summary dialog if the user hasn't yet responded to an invitation
+eventNeedsAction=Nid ydych wedi ymateb eto i'r gwahoddiad
+
+# LOCALIZATION NOTE (taskAccepted) - this will be displayed as notification
+# in the summary dialog if the user has accepted the assigned task
+taskAccepted=Rydych wedi derbyn gweithio ar y dasg hwn
+
+# LOCALIZATION NOTE (taskTentative) - this will be displayed as notification
+# in the summary dialog if the user has accepted tentatively the assigned task
+taskTentative=Rydych wedi derbyn gweithio ar y dasg hwn yn amodol
+
+# LOCALIZATION NOTE (taskDeclined) - this will be displayed as notification
+# in the summary dialog if the user has declined the assigned task
+taskDeclined=Rydych wedi gwrthod gweithio ar y dasg hwn
+
+# LOCALIZATION NOTE (taskDelegated) - this will be displayed as notification
+# in the summary dialog if the user has delegated his/her assignement to one or
+# more others (without attending / working on it his/herself)
+taskDelegated=Rydych wedi dirprwyo gweithio ar y dasg hwn
+
+# LOCALIZATION NOTE (taskNeedsAction) - this will be displayed as notification
+# in the summary dialog if the user hasn't yet responded to the task assignment
+taskNeedsAction=Nid ydych wedi ymateb eto i'r gwahoddiad i'r aseiniad tasg yma
+
+# LOCALIZATION NOTE (taskInProgress) - this will be displayed as notification
+# in the summary dialog if the user is working on an assigned task
+taskInProgress=Rydych wedi dechrau gweithio ar yr aseiniad tasg hwn
+
+# LOCALIZATION NOTE (taskCompleted) - this will be displayed as notification
+# in the summary dialog if the user has completed the work on this assigned task
+taskCompleted=Rydych wedi cwblhau gweithio ar yr aseiniad tasg hwn
+
+# LOCALIZATION NOTE (sendandcloseButtonLabel) - this is a runtime replacement for
+# event.toolbar.saveandclose.label in the event dialog/tab toolbar if attendees
+# will be notified on saving & closing
+sendandcloseButtonLabel=Anfon a Chau
+
+# LOCALIZATION NOTE (sendandcloseButtonTooltip) - this is a runtime replacement for
+# event.toolbar.saveandclose.tooltip in the event dialog/tab toolbar if attendees
+# will be notified on saving & closing
+sendandcloseButtonTooltip=Hysbysu'r mynychwr a chau
+
+# LOCALIZATION NOTE (saveandsendButtonLabel) - this is a runtime replacement for
+# event.toolbar.save.label2 in the event dialog/tab toolbar if attendees
+# will be notified on saving
+saveandsendButtonLabel=Cadw ac Anfon
+
+# LOCALIZATION NOTE (saveandsendButtonTooltip) - this is a runtime replacement
+# for event.toolbar.save.tooltip2 in the event dialog/tab toolbar if attendees
+# will be notified on saving
+saveandsendButtonTooltip=Cadw a hysbysu'r mynychwr
+
+# LOCALIZATION NOTE (saveandsendMenuLabel) - this is a runtime replacement for
+# event.menu.item.save.label in the event dialog/tab toolbar if attendees
+# will be notified on saving
+saveandsendMenuLabel=Cadw ac Anfon
+
+# LOCALIZATION NOTE (sendandcloseMenuLabel) - this is a runtime replacement for
+# event.menu.item.saveandclose.label in the event dialog/tab toolbar if attendees
+# will be notified on saving
+sendandcloseMenuLabel=Cadw a Chau
+
+# LOCALIZATION NOTE (attendeesTabLabel) - this is a runtime replacement for
+# event.attendees.label defined in calendar-event-dialog.dtd and used in the
+# event dialog/tab as attendee tab label if an event has at least one attendee
+# %1$S - the number of attendee (1-n)
+attendeesTabLabel=Mynychwyr (%1$S):
+
+# LOCALIZATION NOTE (attachmentsTabLabel) - this is a runtime replacement for
+# event.attachments.label defined in calendar-event-dialog.dtd and used in the
+# event dialog/tab as attendee tab label if an event has at least one attachment
+# %1$S - the number of attachments (1-n)
+attachmentsTabLabel=Atodiadau (%1$S):
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-extract.properties b/l10n-cy/calendar/chrome/calendar/calendar-extract.properties
new file mode 100644
index 0000000000..1f5182b6e2
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-extract.properties
@@ -0,0 +1,294 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+# Strings here are used to create events and tasks with start and end times
+# based on email content.
+# None of the strings are displayed in the user interface.
+#
+# You don't have to fill all from.*, until.*, *.prefix and *.suffix patterns.
+# It's ok to leave some empty.
+# Please consider declensions and gender if your language has them.
+# Don't just translate directly. The number of variants doesn't have to be
+# the same as in en-US. All of 0, 1, 2, etc is allowed in patterns except alphabet
+# pattern. You can and should add language specific variants.
+#
+# There are two different ways to find a start time text in email:
+# 1) it matches a from.* pattern and does not have end.prefix or end.suffix next to it
+# 2) it matches until.* pattern and has start.prefix or start.suffix next to it
+# Similar inverse logic applies to end times.
+# These rules enable using prefix and suffix values with only start.* or only until.*
+# patterns localized for some languages and thus not having to repeat the same
+# values in both.
+#
+# Patterns are partially space-insensitive.
+# "deadline is" pattern will find both "deadlineis" and "deadline  is"
+# but "deadlineis" won't find "deadline is" or "deadline  is".
+# Therefore you should include all spaces that are valid within a pattern.
+
+# LOCALIZATION NOTE (start.prefix):
+# datetimes with these in front are extracted as start times
+# can be a list of values, separate variants by |
+start.prefix =
+
+# LOCALIZATION NOTE (start.suffix):
+# datetimes followed by these are extracted as start times
+start.suffix = gan | tan | at | - | nes | nes | a
+
+# LOCALIZATION NOTE (end.prefix):
+# datetimes with these in front are extracted as end times
+end.prefix = gan | tan | at | - | nes | nes | a | erbyn: | erbyn | diweddu | y terfyn yw | terfyn:
+
+# LOCALIZATION NOTE (end.suffix):
+# datetimes followed by these are extracted as end times
+# can be a list of values, separate variants by |
+end.suffix =
+
+# LOCALIZATION NOTE (no.datetime.prefix):
+# datetimes with these in front won't be used
+# specify full words here
+no.datetime.prefix = wythnos diwethaf | anfonwyd | e-bost | yn lle | yn anffodus | o fewn | nid
+
+# LOCALIZATION NOTE (no.datetime.suffix):
+# datetimes followed by these won't be used
+no.datetime.suffix = llawr | flr | : | e-bost | e-bost | > | % | usd | doleri | $
+
+# LOCALIZATION NOTE (from.*):
+# can be a list of values, separate variants by |
+
+# LOCALIZATION NOTE (from.today):
+# must not be empty!
+from.today = heddiw
+
+from.tomorrow = yfory
+# LOCALIZATION NOTE (until.*):
+# can be a list of values, separate variants by |
+until.tomorrow =
+
+# LOCALIZATION NOTE (from.ordinal.date):
+# #1 = matches numbers 1-31 and number.x
+# should not have "#1" as this would match any single number in email to a time
+from.ordinal.date = #1af | #1ail | #1yddd | #1edd
+
+# LOCALIZATION NOTE (until.ordinal.date):
+# #1 = matches numbers 1-31 and number.x
+until.ordinal.date =
+
+from.noon = canol dydd
+until.noon =
+
+# LOCALIZATION NOTE (from.hour):
+# #1 = matches numbers 0-23 and number.0-number.23
+# should not have "#1" as this would match any single number in email to a time
+from.hour = am #1 | tua #1 | #1 - | #1 tan
+
+# LOCALIZATION NOTE (until.hour):
+# #1 = matches numbers 0-23 and number.0-number.23
+# should also list how to find end of a timeframe
+until.hour = - #1 | tan #1 | tan #1 | erbyn #1
+
+# LOCALIZATION NOTE (from.hour.am):
+# #1 = matches numbers 0-23 and number.0-number.23
+from.hour.am = #1 am | #1 a.m
+
+# LOCALIZATION NOTE (until.hour.am):
+# #1 = matches numbers 0-23 and number.0-number.23
+# should also list how to find end of a timeframe
+until.hour.am =
+
+# LOCALIZATION NOTE (from.hour.pm):
+# #1 = matches numbers 0-23 and number.0-number.23
+from.hour.pm = #1 pm | #1 p.m | #1 p
+
+# LOCALIZATION NOTE (until.hour.pm):
+# #1 = matches numbers 0-23 and number.0-number.23
+# should also list how to find end of a timeframe
+until.hour.pm =
+
+# LOCALIZATION NOTE (from.half.hour.before):
+# denotes times 30 minutes before next full hour
+from.half.hour.before = hanner awr cyn #1
+
+# LOCALIZATION NOTE (until.half.hour.before):
+# denotes times 30 minutes before next full hour
+until.half.hour.before =
+
+# LOCALIZATION NOTE (from.half.hour.after):
+# denotes times 30 minutes after last full hour
+from.half.hour.after = hanner wedi #1
+
+# LOCALIZATION NOTE (until.half.hour.after):
+# denotes times 30 minutes after last full hour
+until.half.hour.after =
+
+# LOCALIZATION NOTE (from.hour.minutes):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+from.hour.minutes = #1:#2 | am #1#2
+
+# LOCALIZATION NOTE (until.hour.minutes):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+until.hour.minutes =
+
+# LOCALIZATION NOTE (from.hour.minutes.am):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+from.hour.minutes.am = #1:#2 am | #1:#2 a.m
+
+# LOCALIZATION NOTE (until.hour.minutes.am):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+until.hour.minutes.am =
+
+# LOCALIZATION NOTE (from.hour.minutes.pm):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+from.hour.minutes.pm = #1:#2 pm | #1:#2 p.m | #1:#2 p
+
+# LOCALIZATION NOTE (until.hour.minutes.pm):
+# #1 = matches numbers 0-23
+# #2 = matches numbers 0-59
+until.hour.minutes.pm =
+
+# LOCALIZATION NOTE (from.monthname.day):
+# #1 = matches numbers 1-31 and number.x
+# #2 = matches monthname
+from.monthname.day = #1 #2 | #2 #1 | #2 #1af | #2 #1ail | #2 #1ydd | #2 #1edd | #1af o #2 | #1ail o #2 | #1ydd o #2 | #1ed o #2
+
+# LOCALIZATION NOTE (until.monthname.day):
+# #1 = matches numbers 1-31
+# #2 = matches monthname
+until.monthname.day =
+
+# LOCALIZATION NOTE (from.month.day):
+# #1 = matches numbers 1-31
+# #2 = matches numbers 1-12
+from.month.day = #2/#1
+
+# LOCALIZATION NOTE (until.month.day):
+# #1 = matches numbers 1-31 and number.x
+# #2 = matches numbers 1-12
+until.month.day =
+
+# LOCALIZATION NOTE (from.year.month.day):
+# #1 = matches numbers 1-31
+# #2 = matches numbers 1-12
+# #3 = matches 2/4 numbers
+from.year.month.day = #2/#1/#3 | #3/#2/#1 | #3-#2-#1
+
+# LOCALIZATION NOTE (until.year.month.day):
+# #1 = matches numbers 1-31
+# #2 = matches numbers 1-12
+# #3 = matches 2/4 numbers
+until.year.month.day =
+
+# LOCALIZATION NOTE (from.year.monthname.day):
+# #1 = matches numbers 1-31
+# #2 = matches monthname
+# #3 = matches 2/4 numbers
+from.year.monthname.day = #1 #2 #3 | #1af #2 #3 | #1ydd #2 #3 | #1rd #2 #3 | #1th #2 #3 | #2 #1, #3 | #3-#2-#1
+
+# LOCALIZATION NOTE (until.year.monthname.day):
+# #1 = matches numbers 1-31
+# #2 = matches monthname
+# #3 = matches 2/4 numbers
+until.year.monthname.day =
+
+# LOCALIZATION NOTE (duration.*):
+# can be a list of values, separate variants by |
+
+# LOCALIZATION NOTE (duration.minutes):
+# #1 = matches 1/2 numbers and number.0 - and number.31
+duration.minutes = #1 munud| #1 mun | #1 mun
+
+# LOCALIZATION NOTE (duration.hours):
+# #1 = matches 1/2 numbers and number.0 - and number.31
+duration.hours = #1 awr| #1 awr
+
+# LOCALIZATION NOTE (duration.days):
+# #1 = matches 1/2 numbers and number.0 - and number.31
+duration.days = #1 diwrnod
+
+# LOCALIZATION NOTE (month.*):
+# can be a list of values, separate variants by |
+month.1 = ionawr | ion | ion.
+month.2 = chwefror | chw | chw.
+month.3 = mawrth | maw | maw.
+month.4 = ebrill | ebr | ebr.
+month.5 = mai
+month.6 = mehefin | meh | meh.
+month.7 = gorffennaf | gor | gor.
+month.8 = awst | aws | aws.
+month.9 = medi | med | med. | medi.
+month.10 = hydref | hyd | hyd.
+month.11 = tachwedd | tac | tac.
+month.12 = rhagfyr | rha | rha.
+
+# LOCALIZATION NOTE (from.weekday.*):
+# used to derive start date based on weekdays mentioned
+# can be a list of values, separate variants by |
+# LOCALIZATION NOTE (from.weekday.0):
+# Regardless of what the first day of the week is in your country, 0 is Sunday here.
+from.weekday.0 = dydd sul | dyddiau sul
+from.weekday.1 = dydd llun | dyddiau llun
+from.weekday.2 = dydd mawrth | dyddiau mawrth
+from.weekday.3 = dydd mercher | dyddiau mercher
+from.weekday.4 = dydd iau | dyddiau iau
+from.weekday.5 = dydd gwener | dyddiau gwener
+from.weekday.6 = dydd sadwrn | dyddiau sadwrn
+
+# LOCALIZATION NOTE (until.weekday.*):
+# used to derive end date based on weekdays mentioned
+# can be a list of values, separate variants by |
+# LOCALIZATION NOTE (until.weekday.0):
+# Regardless of what the first day of the week is in your country, 0 is Sunday here.
+until.weekday.0 =
+until.weekday.1 =
+until.weekday.2 =
+until.weekday.3 =
+until.weekday.4 =
+until.weekday.5 =
+until.weekday.6 =
+
+# LOCALIZATION NOTE (number.*):
+# used within other patterns to understand dates where day of month isn't written with digits
+# can be a list of values, separate variants by |
+number.0 = sero
+number.1 = un | cyntaf
+number.2 = dau | ail
+number.3 = tri | trydydd
+number.4 = pedwar | pedwerydd
+number.5 = pump | pumed
+number.6 = chwech | chweched
+number.7 = saith | seithfed
+number.8 = wyth | wythfed
+number.9 = naw | nawfed
+number.10 = deg | degfed
+number.11 = un ar ddeg | unfed ar ddeg
+number.12 = deuddeg | deuddegfed
+number.13 = un deg tri | trydydd ar ddeg
+number.14 = un deg | pedwar | pedwerydd ar ddeg
+number.15 = un deg pump | pymthegfed
+number.16 = un deg chwech | unfed ar bymtheg
+number.17 = un deg saith | dau ar bymtheg
+number.18 = un deg wyth | deunawfed
+number.19 = un deg naw | pedwerydd ar bymtheg
+number.20 = dau ddeg | ugeinfed
+number.21 = dau ddeg un | unfed ar hugain
+number.22 = dau ddeg dau | ail ar hugain
+number.23 = dau ddeg tri | trydydd ar hugain
+number.24 = dau ddeg pedwar | pedwerydd ar hugain
+number.25 = dau ddeg pump | pumed ar hugain
+number.26 = dau ddeg chwech | chweched ar hugain
+number.27 = dau ddeg saith | seithfed ar hugain
+number.28 = dau ddeg wyth | wythfed ar hugain
+number.29 = dau ddeg naw | nawfed ar hugain
+number.30 = trideg | degfed ar hugain
+number.31 = tri deg un | unfed ar ddeg ar hugain
+
+# LOCALIZATION NOTE (alphabet):
+# list all lower and uppercase letters if your language has an alphabet
+# otherwise leave it empty
+alphabet = abcchdddefffgnghilllmnopphrstthuwyABCCHDDDEFFFGNGHILLLMNOPPHRSTTHUWY
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.dtd b/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.dtd
new file mode 100644
index 0000000000..7be18a498f
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
+<!-- Calendar Invitations Dialog -->
+
+<!ENTITY calendar.invitations.dialog.invitations.text                   "Gwahoddiadau">
+<!ENTITY calendar.invitations.dialog.statusmessage.updating.text        "Diweddaru'r rhestr gwahoddedigion.">
+<!ENTITY calendar.invitations.dialog.statusmessage.noinvitations.text   "Heb ganfod gwahoddiadau heb eu cadarnhau.">
+<!-- Calendar Invitations List -->
+
+<!ENTITY calendar.invitations.list.accept.button.label                  "Derbyn">
+<!ENTITY calendar.invitations.list.decline.button.label                 "Gwrthod">
+<!ENTITY calendar.invitations.list.recurrentevent.text                  "Digwyddiad ailadroddus">
+<!ENTITY calendar.invitations.list.alldayevent.text                     "Digwyddiad drwy'r dydd">
+<!ENTITY calendar.invitations.list.location.text                        "Lleoliad: ">
+<!ENTITY calendar.invitations.list.organizer.text                       "Trefnydd: ">
+<!ENTITY calendar.invitations.list.attendee.text                        "Mynychwr: ">
+<!ENTITY calendar.invitations.list.none.text                            "Dim">
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.properties b/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.properties
new file mode 100644
index 0000000000..c6d9237723
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-invitations-dialog.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+allday-event=Digwyddiad diwrnod cyfan
+recurrent-event=Digwyddiad sy'n ddigwydd eto
+location=Lleoliad: %S
+organizer=Trefnydd: %S
+attendee=Mynychwr: %S
+none=Dim
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.dtd b/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.dtd
new file mode 100644
index 0000000000..403da0c517
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY buttons.occurrence.accesskey "y">
+<!ENTITY buttons.allfollowing.accesskey "f">
+<!ENTITY buttons.parent.accesskey "a">
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.properties b/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.properties
new file mode 100644
index 0000000000..abb2c83df1
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-occurrence-prompt.properties
@@ -0,0 +1,53 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+header.isrepeating.event.label=yn ddigwyddiad sy'n ailadrodd
+header.isrepeating.task.label=yn dasg sy'n ailadrodd\u0020
+header.containsrepeating.event.label=yn cynnwys digwyddiadau sy'n ailadrodd
+header.containsrepeating.task.label=yn cynnwys tasgau sy'n ailadrodd
+header.containsrepeating.mixed.label=yn cynnwys eitemau o fathau gwahanol sy'n ailadrodd
+
+windowtitle.event.copy=Copïo Digwyddid sy'n Ailadrodd
+windowtitle.task.copy=Copïo Tasg sy'n Ailadrodd
+windowtitle.mixed.copy=Copïo Eitemau sy'n Ailadrodd
+windowtitle.event.cut=Torri Digwyddiad sy'n Ailadrodd
+windowtitle.task.cut=Torri Tasgsy'n Ailadrodd
+windowtitle.mixed.cut=Torri Eitemau sy'n Ailadrodd
+windowtitle.event.delete=Dileu Tasg Ailadroddus
+windowtitle.task.delete=Dileu Tasg Ailadroddus
+windowtitle.mixed.delete=Dileu Eitemau sy'n Ailadrodd
+windowtitle.event.edit=Golygu Tasg Ailadroddus
+windowtitle.task.edit=Golygu Tasg Ailadroddus
+windowtitle.mixed.edit=Golygu Eitemau Ailadroddus
+windowtitle.multipleitems=Eitemau dewisiwyd
+
+buttons.single.occurrence.copy.label=Copïo dim ond y tro yma
+buttons.single.occurrence.cut.label=Torri dim ond yr achlysur yma
+buttons.single.occurrence.delete.label=Dileu dim ond yr achlysur yma
+buttons.single.occurrence.edit.label=Golygu dim ond yr achlysur yma
+
+buttons.multiple.occurrence.copy.label=Copïo dim ond yr achlysuron hyn
+buttons.multiple.occurrence.cut.label=Torri dim ond yr achlysuron hyn
+buttons.multiple.occurrence.delete.label=Dileu dim ond yr achlysuron hyn
+buttons.multiple.occurrence.edit.label=Golygu achlysuron penodol
+
+buttons.single.allfollowing.copy.label=Copïo hwn a phob achlysur i'r dyfodol
+buttons.single.allfollowing.cut.label=Torri hwn a phob achlysur i'r dyfodol
+buttons.single.allfollowing.delete.label=Dileu hwn a phob achlysur i'r dyfodol
+buttons.single.allfollowing.edit.label=Golygu hwn a phob achlysur i'r dyfodol
+
+buttons.multiple.allfollowing.copy.label=Copïo hwn a phob achlysur i'r dyfodol
+buttons.multiple.allfollowing.cut.label=Torri hwn a phob achlysur i'r dyfodol
+buttons.multiple.allfollowing.delete.label=Dileu hwn a phob achlysur i'r dyfodol
+buttons.multiple.allfollowing.edit.label=Golygu hwn a phob achlysur i'r dyfodol
+
+buttons.single.parent.copy.label=Copïo pob achlysur
+buttons.single.parent.cut.label=Torri pob achlysur
+buttons.single.parent.delete.label=Dileu pob achlysur
+buttons.single.parent.edit.label=Golygu pob achlysur
+
+buttons.multiple.parent.copy.label=Copïo pob achlysur o'r eitemau hyn
+buttons.multiple.parent.cut.label=Torri pob achlysur o'r eitemau hyn
+buttons.multiple.parent.delete.label=Dileu pob achlysur o'r eitemau hyn
+buttons.multiple.parent.edit.label=Golygu pob achlysur o'r eitemau hyn
diff --git a/l10n-cy/calendar/chrome/calendar/calendar-subscriptions-dialog.dtd b/l10n-cy/calendar/chrome/calendar/calendar-subscriptions-dialog.dtd
new file mode 100644
index 0000000000..b16a9e4ff2
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar-subscriptions-dialog.dtd
@@ -0,0 +1,14 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/.
+-->
+<!-- Calendar Subscriptions Dialog -->
+
+<!ENTITY calendar.subscriptions.dialog.title                            "Tanysgrifio i Galendrau">
+<!ENTITY calendar.subscriptions.dialog.search.label.value               "Dangos calendrau sy'n cynnwys:">
+<!ENTITY calendar.subscriptions.dialog.search.button.label              "Chwilio">
+<!ENTITY calendar.subscriptions.dialog.select.label.value               "Dewis calendrau i danysgrifio iddynt:">
+<!ENTITY calendar.subscriptions.dialog.subscribe.button.label           "Tanysgrifio">
+<!ENTITY calendar.subscriptions.dialog.unsubscribe.button.label         "Dad-danysgrifio">
+<!ENTITY calendar.subscriptions.dialog.statusmessage.busy.label         "Chwilio…">
+<!ENTITY calendar.subscriptions.dialog.statusmessage.nomatches.label    "Heb ganfod cydweddiad.">
diff --git a/l10n-cy/calendar/chrome/calendar/calendar.dtd b/l10n-cy/calendar/chrome/calendar/calendar.dtd
new file mode 100644
index 0000000000..1a900eefc7
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar.dtd
@@ -0,0 +1,407 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- General -->
+<!ENTITY calendar.calendar.label     "Calendr">
+<!ENTITY calendar.calendar.accesskey "C">
+
+<!ENTITY calendar.newevent.button.tooltip         "Creu digwyddiad newydd" >
+<!ENTITY calendar.newtask.button.tooltip          "Creu tasg newydd" >
+
+<!ENTITY calendar.unifinder.showcompletedtodos.label "Dangos Tasgau wedi'u cwblhau">
+
+<!ENTITY calendar.today.button.label          "Heddiw">
+<!ENTITY calendar.tomorrow.button.label       "Yfory">
+<!ENTITY calendar.upcoming.button.label       "I Ddod">
+
+<!ENTITY calendar.events.filter.all.label "Pob Digwyddiad">
+<!ENTITY calendar.events.filter.today.label "Digwyddiadau Heddiw">
+<!ENTITY calendar.events.filter.future.label "Pob Digwyddiad i'r Dyfodol">
+<!ENTITY calendar.events.filter.current.label "Diwrnod Cyfredol wedi'i Ddewis">
+<!ENTITY calendar.events.filter.currentview.label "Digwyddiadau yn y Golwg Gyfredol">
+<!ENTITY calendar.events.filter.next7Days.label "Digwyddiadau yn ystod y 7 Diwrnod Nesaf">
+<!ENTITY calendar.events.filter.next14Days.label "Digwyddiadau yn ystod y 14 Diwrnod Nesaf">
+<!ENTITY calendar.events.filter.next31Days.label "Digwyddiadau yn ystod y 31 Diwrnod Nesaf">
+<!ENTITY calendar.events.filter.thisCalendarMonth.label "Digwyddiadau yn ystod y Mis Calendr yma">
+
+<!-- LOCALIZATION NOTE(calendar.unifinder.tree.done.tooltip)
+   - This label and tooltip is used for the column with the checkbox in the
+   - task tree view. -->
+<!ENTITY calendar.unifinder.tree.done.label                "Gorffen">
+<!ENTITY calendar.unifinder.tree.done.tooltip2             "Trefnu yn ôl eu cwblhau">
+<!ENTITY calendar.unifinder.tree.priority.label            "Blaenoriaeth">
+<!ENTITY calendar.unifinder.tree.priority.tooltip2         "Trefnu yn ôl blaenoriaeth">
+<!ENTITY calendar.unifinder.tree.title.label               "Teitl">
+<!ENTITY calendar.unifinder.tree.title.tooltip2            "Trefnu yn ôl teitl">
+<!ENTITY calendar.unifinder.tree.percentcomplete.label     "Cwblhawyd &#037;">
+<!ENTITY calendar.unifinder.tree.percentcomplete.tooltip2  "Trefnu yn ôl &#037; wedi'u cwblhau">
+<!ENTITY calendar.unifinder.tree.startdate.label           "Cychwyn">
+<!ENTITY calendar.unifinder.tree.startdate.tooltip2        "Trefnu yn ôl dyddiad cychwyn">
+<!ENTITY calendar.unifinder.tree.enddate.label             "Diwedd">
+<!ENTITY calendar.unifinder.tree.enddate.tooltip2          "Trefnu yn ôl dyddiad diwedd">
+<!ENTITY calendar.unifinder.tree.duedate.label             "Erbyn">
+<!ENTITY calendar.unifinder.tree.duedate.tooltip2          "Trefnu yn ôl diwrnod y digwyddiad">
+<!ENTITY calendar.unifinder.tree.completeddate.label       "Cwblhawyd">
+<!ENTITY calendar.unifinder.tree.completeddate.tooltip2    "Trefnu yn ôl dyddiad cwblhau">
+<!ENTITY calendar.unifinder.tree.categories.label          "Categori">
+<!ENTITY calendar.unifinder.tree.categories.tooltip2       "Trefnu yn ôl categori">
+<!ENTITY calendar.unifinder.tree.location.label            "Lleoliad">
+<!ENTITY calendar.unifinder.tree.location.tooltip2         "Trefnu yn ôl lleoliad">
+<!ENTITY calendar.unifinder.tree.status.label              "Statws">
+<!ENTITY calendar.unifinder.tree.status.tooltip2           "Trefnu yn ôl statws">
+<!ENTITY calendar.unifinder.tree.calendarname.label        "Enw Calendr">
+<!ENTITY calendar.unifinder.tree.calendarname.tooltip2     "Trefnu yn ôl enw calendr">
+<!ENTITY calendar.unifinder.tree.duration.label            "Cwblhau ymhen">
+<!ENTITY calendar.unifinder.tree.duration.tooltip2         "Trefnu yn ôl cyfnod hyd y digwyddiad">
+<!ENTITY calendar.unifinder.close.tooltip                  "Cau chwilio digwyddiadau a rhestr digwyddiadau">
+
+<!ENTITY calendar.today.button.tooltip          "Mynd i Heddiw" >
+<!ENTITY calendar.todaypane.button.tooltip      "Dangos Paen Heddiw" >
+
+<!ENTITY calendar.day.button.tooltip            "Newid i golwg diwrnod" >
+<!ENTITY calendar.week.button.tooltip           "Newid i golwg wythnos" >
+<!ENTITY calendar.month.button.tooltip          "Newid i golwg mis" >
+<!ENTITY calendar.multiweek.button.tooltip      "Newid i golwg wythnosol" >
+
+<!ENTITY calendar.nextday.label                 "Diwrnod Nesaf" >
+<!ENTITY calendar.prevday.label                 "Diwrnod Blaenorol" >
+<!ENTITY calendar.nextday.accesskey             "N" >
+<!ENTITY calendar.prevday.accesskey             "B" >
+<!ENTITY calendar.nextweek.label                "Wythnos Nesaf" >
+<!ENTITY calendar.prevweek.label                "Wythnos Flaenorol" >
+<!ENTITY calendar.nextweek.accesskey            "W" >
+<!ENTITY calendar.prevweek.accesskey            "F" >
+<!ENTITY calendar.nextmonth.label               "Mis Nesaf" >
+<!ENTITY calendar.prevmonth.label               "Mis Blaenorol" >
+<!ENTITY calendar.nextmonth.accesskey           "M" >
+<!ENTITY calendar.prevmonth.accesskey           "l" >
+
+<!ENTITY calendar.navigation.nextday.tooltip    "Ymlaen Un Diwrnod" >
+<!ENTITY calendar.navigation.prevday.tooltip    "Yn Diwrnod Nôl" >
+<!ENTITY calendar.navigation.nextweek.tooltip   "Un Wythnos Ymlaen" >
+<!ENTITY calendar.navigation.prevweek.tooltip   "Un Wythnos Nôl" >
+<!ENTITY calendar.navigation.nextmonth.tooltip  "Un Mis Ymlaen" >
+<!ENTITY calendar.navigation.prevmonth.tooltip  "Un Mis Nôl" >
+
+<!ENTITY calendar.newevent.button.label         "Digwyddiad Newydd" >
+<!ENTITY calendar.newtask.button.label          "Tasg Newydd" >
+<!ENTITY calendar.print.button.label            "Argraffu" >
+<!ENTITY calendar.print.button.accesskey        "A">
+
+<!ENTITY calendar.day.button.label              "Diwrnod" >
+<!ENTITY calendar.week.button.label             "Wythnos" >
+<!ENTITY calendar.month.button.label            "Mis" >
+<!ENTITY calendar.multiweek.button.label        "Wythnosau" >
+<!ENTITY calendar.onlyworkday.checkbox.label    "Dyddiau'r wythnos waith yn unig" >
+<!ENTITY calendar.onlyworkday.checkbox.accesskey  "w" >
+<!ENTITY calendar.displaytodos.checkbox.label   "Tasgau mewn Golwg" >
+<!ENTITY calendar.displaytodos.checkbox.accesskey "T" >
+<!ENTITY calendar.completedtasks.checkbox.label     "Dangos Tasgau wedi'u cwblhau" >
+<!ENTITY calendar.completedtasks.checkbox.accesskey "D" >
+
+<!ENTITY calendar.orientation.label "Troi'r Golwg" >
+<!ENTITY calendar.orientation.accesskey "r" >
+
+<!ENTITY calendar.search.options.searchfor " yn cynnwys">
+
+<!ENTITY calendar.list.header.label                 "Calendr">
+
+<!ENTITY calendar.task.filter.title.label           "Dangos">
+<!ENTITY calendar.task.filter.all.label             "Popeth">
+<!ENTITY calendar.task.filter.all.accesskey         "P">
+<!ENTITY calendar.task.filter.today.label           "Heddiw">
+<!ENTITY calendar.task.filter.today.accesskey       "H">
+<!ENTITY calendar.task.filter.next7days.label       "Saith Diwrnod Nesaf">
+<!ENTITY calendar.task.filter.next7days.accesskey   "S">
+<!ENTITY calendar.task.filter.notstarted.label      "Tasgau Heb eu Cychwyn">
+<!ENTITY calendar.task.filter.notstarted.accesskey  "H">
+<!ENTITY calendar.task.filter.overdue.label         "Tasgau Hwyr">
+<!ENTITY calendar.task.filter.overdue.accesskey     "w">
+<!ENTITY calendar.task.filter.completed.label       "Tasgau wedi'u Cwblhau">
+<!ENTITY calendar.task.filter.completed.accesskey   "a">
+<!ENTITY calendar.task.filter.open.label            "Tasgau heb eu Cwblhau">
+<!ENTITY calendar.task.filter.open.accesskey        "g">
+
+<!-- LOCALIZATION NOTE(calendar.task.filter.current.label)
+     "Current Tasks" will show all tasks, except those with a start date set
+     that is after today and after the selected date. If a task repeats, a
+     separate entry will be shown for each of the occurrences that happen on or
+     before today (or the selected date, whichever is later). -->
+<!ENTITY calendar.task.filter.current.label         "Tasgau Cyfredol">
+<!ENTITY calendar.task.filter.current.accesskey     "u">
+
+<!ENTITY calendar.task-details.title.label           "teitl">
+<!ENTITY calendar.task-details.organizer.label       "oddi wrth">
+<!ENTITY calendar.task-details.priority.label        "blaenoriaeth">
+<!ENTITY calendar.task-details.priority.low.label    "Isel">
+<!ENTITY calendar.task-details.priority.normal.label "Arferol">
+<!ENTITY calendar.task-details.priority.high.label   "Uchel">
+<!ENTITY calendar.task-details.status.label          "statws">
+<!ENTITY calendar.task-details.category.label        "categori">
+<!ENTITY calendar.task-details.repeat.label          "ailadrodd">
+<!ENTITY calendar.task-details.attachments.label     "atodiadau">
+<!ENTITY calendar.task-details.start.label           "dyddiad cychwyn">
+<!ENTITY calendar.task-details.due.label             "dyddiad cwblhau">
+
+<!ENTITY calendar.task.category.button.tooltip  "Categoreiddio tasgau">
+<!ENTITY calendar.task.complete.button.tooltip  "Marcio tasgau dewisol wedi'u cwblhau">
+<!ENTITY calendar.task.priority.button.tooltip  "Newid blaenoriaeth">
+
+<!ENTITY calendar.task.text-filter.textbox.emptytext.base1           "Hidlo tasgau #1">
+<!ENTITY calendar.task.text-filter.textbox.emptytext.keylabel.nonmac "&lt;Ctrl+Shift+K&gt;">
+<!ENTITY calendar.task.text-filter.textbox.emptytext.keylabel.mac    "&lt;&#x21E7;&#x2318;K&gt;">
+
+<!-- Context Menu -->
+<!ENTITY calendar.context.modifyorviewitem.label      "Agor">
+<!ENTITY calendar.context.modifyorviewitem.accesskey  "A">
+<!ENTITY calendar.context.modifyorviewtask.label      "Agor Tasg…">
+<!ENTITY calendar.context.modifyorviewtask.accesskey  "T">
+<!ENTITY calendar.context.newevent.label              "Digwyddiad Newydd…">
+<!ENTITY calendar.context.newevent.accesskey          "i">
+<!ENTITY calendar.context.newtodo.label               "Tasgau Newydd…">
+<!ENTITY calendar.context.newtodo.accesskey           "a">
+<!ENTITY calendar.context.deletetask.label            "Dileu Tasg">
+<!ENTITY calendar.context.deletetask.accesskey        "l">
+<!ENTITY calendar.context.deleteevent.label           "Dileu Digwyddiad">
+<!ENTITY calendar.context.deleteevent.accesskey       "e">
+<!ENTITY calendar.context.cutevent.label              "Torri">
+<!ENTITY calendar.context.cutevent.accesskey          "T">
+<!ENTITY calendar.context.copyevent.label             "Copïo">
+<!ENTITY calendar.context.copyevent.accesskey         "C">
+<!ENTITY calendar.context.pasteevent.label            "Gludo">
+<!ENTITY calendar.context.pasteevent.accesskey        "G">
+<!ENTITY calendar.context.button.label                "Paen Heddiw">
+<!ENTITY calendar.context.button.accesskey            "P">
+
+<!ENTITY calendar.context.attendance.menu.label                 "Presenoldeb">
+<!ENTITY calendar.context.attendance.menu.accesskey             "r">
+<!ENTITY calendar.context.attendance.occurrence.label           "Achlysur">
+<!ENTITY calendar.context.attendance.all2.label                 "Cyfres Gyfan">
+<!ENTITY calendar.context.attendance.send.label                 "Anfon hysbysiad nawr">
+<!ENTITY calendar.context.attendance.send.accesskey             "A">
+<!ENTITY calendar.context.attendance.dontsend.label             "Peidio anfon hysbysiad">
+<!ENTITY calendar.context.attendance.dontsend.accesskey         "P">
+
+<!ENTITY calendar.context.attendance.occ.accepted.accesskey     "e">
+<!ENTITY calendar.context.attendance.occ.accepted.label         "Derbyn">
+<!ENTITY calendar.context.attendance.occ.tentative.accesskey    "y">
+<!ENTITY calendar.context.attendance.occ.tentative.label        "Derbyn yn amodol">
+<!ENTITY calendar.context.attendance.occ.declined.accesskey     "g">
+<!ENTITY calendar.context.attendance.occ.declined.label         "Gwrthod">
+<!ENTITY calendar.context.attendance.occ.delegated.accesskey    "r">
+<!ENTITY calendar.context.attendance.occ.delegated.label        "Dirprwyo">
+<!ENTITY calendar.context.attendance.occ.needsaction.accesskey  "G">
+<!ENTITY calendar.context.attendance.occ.needsaction.label      "Angen gwaith">
+<!ENTITY calendar.context.attendance.occ.inprogress.accesskey   "W">
+<!ENTITY calendar.context.attendance.occ.inprogress.label       "Ar waith">
+<!ENTITY calendar.context.attendance.occ.completed.accesskey    "W">
+<!ENTITY calendar.context.attendance.occ.completed.label        "Wedi cwblhau">
+
+<!ENTITY calendar.context.attendance.all.accepted.accesskey     "d">
+<!ENTITY calendar.context.attendance.all.accepted.label         "Wedi derbyn">
+<!ENTITY calendar.context.attendance.all.tentative.accesskey    "a">
+<!ENTITY calendar.context.attendance.all.tentative.label        "Derbyn yn amodol">
+<!ENTITY calendar.context.attendance.all.declined.accesskey     "w">
+<!ENTITY calendar.context.attendance.all.declined.label         "Gwrthod">
+<!ENTITY calendar.context.attendance.all.delegated.accesskey    "p">
+<!ENTITY calendar.context.attendance.all.delegated.label        "Dirprwyo">
+<!ENTITY calendar.context.attendance.all.needsaction.accesskey  "n">
+<!ENTITY calendar.context.attendance.all.needsaction.label      "Dal angen gwaith">
+<!ENTITY calendar.context.attendance.all.inprogress.accesskey   "a">
+<!ENTITY calendar.context.attendance.all.inprogress.label       "Ar waith">
+<!ENTITY calendar.context.attendance.all.completed.accesskey    "h">
+<!ENTITY calendar.context.attendance.all.completed.label        "Wedi cwblhau">
+
+<!-- Task Context Menu -->
+<!ENTITY calendar.context.progress.label              "Cynnydd">
+<!ENTITY calendar.context.progress.accesskey          "y">
+<!ENTITY calendar.context.priority.label              "Blaenoriaeth">
+<!ENTITY calendar.context.priority.accesskey          "B">
+<!ENTITY calendar.context.postpone.label              "Gohirio Tasg">
+<!ENTITY calendar.context.postpone.accesskey          "G">
+
+<!ENTITY percnt "&#38;#37;" ><!--=percent sign-->
+
+<!ENTITY calendar.context.markcompleted.label     "Marcio wedi'i Gwblhau">
+<!ENTITY calendar.context.markcompleted.accesskey "G">
+
+<!ENTITY progress.level.0             "0&percnt; wedi'i Gwblhau">
+<!ENTITY progress.level.0.accesskey   "0">
+<!ENTITY progress.level.25            "25&percnt; wedi'i Gwblhau">
+<!ENTITY progress.level.25.accesskey  "2">
+<!ENTITY progress.level.50            "50&percnt; wedi'i Gwblhau">
+<!ENTITY progress.level.50.accesskey  "5">
+<!ENTITY progress.level.75            "75&percnt; wedi'i Gwblhau">
+<!ENTITY progress.level.75.accesskey  "7">
+<!ENTITY progress.level.100            "Cwblhawyd 100&percnt;">
+<!ENTITY progress.level.100.accesskey  "1">
+
+<!ENTITY priority.level.none                "Heb ddiffinio">
+<!ENTITY priority.level.none.accesskey      "e">
+<!ENTITY priority.level.low                 "Isel">
+<!ENTITY priority.level.low.accesskey       "I">
+<!ENTITY priority.level.normal              "Arferol">
+<!ENTITY priority.level.normal.accesskey    "A">
+<!ENTITY priority.level.high                "Uchel">
+<!ENTITY priority.level.high.accesskey      "U">
+
+<!ENTITY calendar.context.postpone.1hour.label      "1 Awr">
+<!ENTITY calendar.context.postpone.1hour.accesskey  "1">
+<!ENTITY calendar.context.postpone.1day.label       "1 Diwrnod">
+<!ENTITY calendar.context.postpone.1day.accesskey   "D">
+<!ENTITY calendar.context.postpone.1week.label      "1 Wythnos">
+<!ENTITY calendar.context.postpone.1week.accesskey  "W">
+
+<!ENTITY calendar.copylink.label       "Copïo Lleoliad Dolen">
+<!ENTITY calendar.copylink.accesskey   "D">
+
+<!-- Task View -->
+<!-- Note that the above *.context.* strings are currently used for the other
+     task action buttons -->
+<!ENTITY calendar.taskview.delete.label     "Dileu">
+
+<!-- Server Context Menu -->
+<!ENTITY calendar.context.newserver.label              "Calendr Newydd…">
+<!ENTITY calendar.context.newserver.accesskey          "N">
+<!ENTITY calendar.context.findcalendar.label           "Canfod Calendr…" >
+<!ENTITY calendar.context.findcalendar.accesskey       "C" >
+<!ENTITY calendar.context.deleteserver2.label          "Dileu Calendr…">
+<!ENTITY calendar.context.deleteserver2.accesskey      "D">
+
+<!-- LOCALIZATION NOTE (calendar.context.removeserver.label): Removing the
+      calendar is the general action of removing it, while deleting means to
+      clear the data and unsubscribing means just taking it out of the calendar
+      list. -->
+<!ENTITY calendar.context.removeserver.label           "Tynnu Calendr…">
+<!ENTITY calendar.context.removeserver.accesskey       "T">
+<!ENTITY calendar.context.unsubscribeserver.label      "Dad-danysgrifio i Galendr…">
+<!ENTITY calendar.context.unsubscribeserver.accesskey  "D">
+<!ENTITY calendar.context.synccalendars.label          "Cydweddu Calendrau">
+<!ENTITY calendar.context.synccalendars.accesskey      "C">
+<!ENTITY calendar.context.publish.label                "Cyhoeddi Calendr…">
+<!ENTITY calendar.context.publish.accesskey            "C">
+<!ENTITY calendar.context.export.label                 "Allforio Calendr…">
+<!ENTITY calendar.context.export.accesskey             "A">
+<!ENTITY calendar.context.properties.label             "Priodweddau">
+<!ENTITY calendar.context.properties.accesskey         "P">
+
+<!-- LOCALIZATION NOTE (calendar.context.showcalendar.accesskey)
+     This is the access key used for the showCalendar string -->
+<!ENTITY calendar.context.showcalendar.accesskey      "d">
+
+<!-- LOCALIZATION NOTE (calendar.context.hidecalendar.accesskey)
+     This is the access key used for the hideCalendar string -->
+<!ENTITY calendar.context.hidecalendar.accesskey      "U">
+
+<!-- LOCALIZATION NOTE (calendar.context.showonly.accesskey)
+     This is the access key used for the showOnlyCalendar string -->
+<!ENTITY calendar.context.showonly.accesskey           "D">
+<!ENTITY calendar.context.showall.label                "Dangos Pob Calendr">
+<!ENTITY calendar.context.showall.accesskey            "P">
+
+<!ENTITY calendar.context.convertmenu.label              "Trosi I">
+<!ENTITY calendar.context.convertmenu.accesskey.mail     "n">
+<!ENTITY calendar.context.convertmenu.accesskey.calendar "T">
+<!ENTITY calendar.context.convertmenu.event.label        "Digwyddiad…">
+<!ENTITY calendar.context.convertmenu.event.accesskey    "D">
+<!ENTITY calendar.context.convertmenu.message.label      "Neges…">
+<!ENTITY calendar.context.convertmenu.message.accesskey  "N">
+<!ENTITY calendar.context.convertmenu.task.label         "Tasg…">
+<!ENTITY calendar.context.convertmenu.task.accesskey     "T">
+
+<!ENTITY calendar.tasks.view.minimonth.label           "Mis Bach">
+<!ENTITY calendar.tasks.view.minimonth.accesskey       "B">
+
+<!ENTITY calendar.tasks.view.calendarlist.label        "Rhestr Calendr">
+<!ENTITY calendar.tasks.view.calendarlist.accesskey    "R">
+
+<!ENTITY calendar.tasks.view.filtertasks.label           "Hidlo Tasgau">
+<!ENTITY calendar.tasks.view.filtertasks.accesskey       "H">
+
+<!-- Calendar Alarm Dialog -->
+
+<!ENTITY calendar.alarm.location.label              "Lleoliad:" >
+<!ENTITY calendar.alarm.details.label               "Manylion…" >
+
+<!ENTITY calendar.alarm.snoozefor.label             "Cysgu am" >
+<!ENTITY calendar.alarm.snoozeallfor.label          "Cysgu Popeth am" >
+<!ENTITY calendar.alarm.title.label                 "Atgoffwyr Calendr" >
+<!ENTITY calendar.alarm.dismiss.label               "Cau" >
+<!ENTITY calendar.alarm.dismissall.label            "Cau Popeth" >
+
+<!ENTITY calendar.alarm.snooze.5minutes.label       "5 Munud" >
+<!ENTITY calendar.alarm.snooze.10minutes.label      "10 Munud" >
+<!ENTITY calendar.alarm.snooze.15minutes.label      "15 Munud" >
+<!ENTITY calendar.alarm.snooze.30minutes.label      "30 Munud" >
+<!ENTITY calendar.alarm.snooze.45minutes.label      "45 Munud" >
+<!ENTITY calendar.alarm.snooze.1hour.label          "1 Awr" >
+<!ENTITY calendar.alarm.snooze.2hours.label         "2 Awr" >
+<!ENTITY calendar.alarm.snooze.1day.label           "1 Diwrnod" >
+
+<!-- LOCALIZATION NOTE (calendar.alarm.snooze.cancel)
+     This string is not seen in the UI, it is read by screen readers when the
+     user focuses the "Cancel" button in the "Snooze for..." popup of the alarm
+     dialog. -->
+<!ENTITY calendar.alarm.snooze.cancel               "Diddymu Cysgu">
+
+<!-- Calendar Server Dialog -->
+<!ENTITY calendar.server.dialog.title.edit          "Golygu'r Calendr">
+<!ENTITY calendar.server.dialog.name.label          "Enw'r Calendr:">
+
+<!-- Calendar Properties -->
+<!ENTITY calendarproperties.color.label                    "Lliw:">
+<!ENTITY calendarproperties.webdav.label                   "iCalendar (ICS)">
+<!ENTITY calendarproperties.caldav.label                   "CalDAV">
+<!ENTITY calendarproperties.format.label                   "Fformat:">
+<!ENTITY calendarproperties.location.label                 "Lleoliad:">
+<!ENTITY calendarproperties.refreshInterval.label          "Adnewyddu'r Calendr:">
+<!ENTITY calendarproperties.refreshInterval.manual.label   "Gyda Llaw">
+<!ENTITY calendarproperties.name.label                     "Enw:">
+<!ENTITY calendarproperties.readonly.label                 "Darllen yn Unig">
+<!ENTITY calendarproperties.firealarms.label               "Dangos Atgoffwyr">
+<!ENTITY calendarproperties.cache3.label                   "Cefnogaeth All-lein">
+<!ENTITY calendarproperties.enabled2.label                 "Galluogi'r Calendr hwn">
+<!ENTITY calendarproperties.forceDisabled.label            "Nid oes modd canfod darparwr y calendr hwn. Mae hyn yn digwydd yn aml os ydych wedi analluogi neu ddadosod rhai ychwanegion.">
+<!ENTITY calendarproperties.unsubscribe.label              "Dad-danysgrifio">
+<!ENTITY calendarproperties.unsubscribe.accesskey          "a">
+
+<!-- Calendar Publish Dialog -->
+<!ENTITY calendar.publish.dialog.title              "Cyhoeddi Calendr">
+<!ENTITY calendar.publish.url.label                 "URL Cyhoeddi">
+<!ENTITY calendar.publish.publish.button      "Cyhoeddi">
+<!ENTITY calendar.publish.close.button      "Cau">
+
+<!ENTITY calendar.publish.example.url.description   "Rhywbeth fel http://www.myserver.com/webdav/test.ics">
+
+<!-- Select Calendar Dialog -->
+<!ENTITY calendar.select.dialog.title    "Dewis Calendr">
+
+<!-- Calendar Printing -->
+<!ENTITY calendar.print.window.title "Argraffu Calendr">
+<!ENTITY calendar.print.title.label "Teitl:">
+<!ENTITY calendar.print.layout.label "Cynllun:">
+<!ENTITY calendar.print.range.label "Beth i Argraffu">
+<!ENTITY calendar.print.currentView2.label "Golwg gyfredol">
+<!ENTITY calendar.print.selectedEventsAndTasks.label "Digwyddiadau/tasgau dewiswyd">
+<!ENTITY calendar.print.tasks.label "Tasgau">
+<!ENTITY calendar.print.events.label "Digwyddiadau">
+<!ENTITY calendar.print.custom.label "Ystod dyddiadau cyfaddas:">
+<!ENTITY calendar.print.from.label "Oddi wrth:">
+<!ENTITY calendar.print.to.label "Hyd:">
+<!ENTITY calendar.print.settingsGroup.label "Gosodiadau Argraffu">
+<!ENTITY calendar.print.optionsGroup.label "Dewisiadau">
+<!ENTITY calendar.print.taskswithnoduedate.label "Tasgau heb ddyddiad cwblhau">
+<!ENTITY calendar.print.completedtasks.label "Tasgau wedi'u cwblhau">
+
+<!-- Error reporting -->
+<!ENTITY calendar.error.detail "Manylion…">
+<!ENTITY calendar.error.code "Cod gwall:">
+<!ENTITY calendar.error.description "Disgrifiad:">
+<!ENTITY calendar.error.title "Digwyddodd gwall">
+
+<!-- Extract buttons in message header -->
+<!ENTITY calendar.extract.event.button         "Ychwanegu digwyddiad">
+<!ENTITY calendar.extract.task.button          "Ychwanegu fel tasg">
+<!ENTITY calendar.extract.event.button.tooltip "Tynnu gwybodaeth calendr o'r neges a'i ychwanegu i'ch calendr fel digwyddiad">
+<!ENTITY calendar.extract.task.button.tooltip  "Tynnu gwybodaeth calendr o'r neges a'i ychwanegu i'ch calendr fel tasg">
diff --git a/l10n-cy/calendar/chrome/calendar/calendar.properties b/l10n-cy/calendar/chrome/calendar/calendar.properties
new file mode 100644
index 0000000000..d4dccc247f
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendar.properties
@@ -0,0 +1,794 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Misc. strings in JS
+
+# LOCALIZATION NOTE (PrintPreviewWindowTitle):
+#    %1$S will be replaced with the title of a html frame
+PrintPreviewWindowTitle=Rhagolwg Argraffu o %1$S
+Untitled=Dim Teitl
+
+# Default name for new events
+newEvent=Digwyddiad Newydd
+
+# Titles for the event/task dialog
+newEventDialog=Digwyddiad Newydd
+editEventDialog=Golygu Digwyddiad
+newTaskDialog=Tasg Newydd
+editTaskDialog=Golygu Tasg
+
+# Do you want to save changes?
+askSaveTitleEvent=Cadw Digwyddiad
+askSaveTitleTask=Cadw Tasg
+askSaveMessageEvent=Nid yw'r digwyddiad wedi'i gadw. Hoffech chi gadw'r digwyddiad?
+askSaveMessageTask=Nid yw'r dasg wedi'i chadw. Hoffech chi gadw'r dasg?
+
+# Event Dialog Warnings
+warningEndBeforeStart=Mae'r dyddiad gorffen yn digwydd ar ôl y dyddiad cychwyn
+warningUntilDateBeforeStart=Mae'r dyddiad tan yn digwydd cyn y dyddiad cychwyn
+
+# The name of the calendar provided with the application by default
+homeCalendarName=Cartref
+
+# The name given to a calendar if an opened calendar has an empty filename
+untitledCalendarName=Calendr heb Deitl
+
+# Event status: Tentative, Confirmed, Cancelled
+# ToDo task status: NeedsAction, InProcess, Completed, Cancelled
+statusTentative     =Amodol
+statusConfirmed     =Cadarnhawyd
+eventStatusCancelled=Diddymwyd
+todoStatusCancelled =Diddymwyd
+statusNeedsAction   =Angen Gweithredu
+statusInProcess     =Ar Waith
+statusCompleted     =Cwblhawyd
+
+# Task priority, these should match the priority.level.* labels in calendar.dtd
+highPriority=Uchel
+normalPriority=Arferol
+lowPriority=Isel
+
+importPrompt=I ba galendr hoffech chi fewnforio'r eitemau hyn?
+exportPrompt=O ba galendr hoffech chi allforio ohono?
+pastePrompt=I ba un o'ch calendrau ysgrifenadwy cyfredol hoffech chi ludo iddo?
+publishPrompt=Pa galendr hoffech chi gyhoeddi?
+
+# LOCALIZATION NOTE (pasteEventAlso): The users pasting operation includes among
+# others also a meeting invitation - this is used as a affix in
+# pasteNotifyAbout
+pasteEventAlso=Mae eich gludo'n cynnwys cyfarfod
+# LOCALIZATION NOTE (pasteEventsAlso): The users pasting operation includes among
+# others also several meeting invitations  - this is used as a affix in
+# pasteNotifyAbout
+pasteEventsAlso=Mae eich gludo'n cynnwys cyfarfodydd
+# LOCALIZATION NOTE (pasteTaskAlso): The users pasting operation includes among
+# others also an assigned task - this is used as a affix in pasteNotifyAbout
+pasteTaskAlso=Mae eich gludo'n cynnwys aseiniad tasg
+# LOCALIZATION NOTE (pasteTasksAlso): The users pasting operation include among
+# others also several assigned tasks - this is used as a affix in
+# pasteNotifyAbout
+pasteTasksAlso=Mae eich gludo'n cynnwys aseiniad tasgau
+# LOCALIZATION NOTE (pasteItemsAlso): The users pasting operation includes among
+# others also assigned task(s) and meeting invitation(s) - this is used as a affix
+# in pasteNotifyAbout
+pasteItemsAlso=Mae eich gludo'n cynnwys cyfarfodydd ac aseiniad tasgau
+# LOCALIZATION NOTE (pasteEventOnly): The users is pasting a meeting -
+# this is used as a affix in pasteNotifyAbout
+pasteEventOnly=Rydych yn gludo cyfarfod
+# LOCALIZATION NOTE (pasteEventsOnly): The users is pasting several meetings -
+# this is used as a affix in pasteNotifyAbout
+pasteEventsOnly=Rydych yn gludo cyfarfodydd
+# LOCALIZATION NOTE (pasteEventOnly): The users is pasting an assigned task -
+# this is used as a affix in pasteNotifyAbout
+pasteTaskOnly=Rydych yn gludo aseiniad tasg
+# LOCALIZATION NOTE (pasteEventsOnly): The users is pasting several assigned
+# tasks - this is used as a affix in pasteNotifyAbout
+pasteTasksOnly=Rydych yn gludo aseiniad tasgau
+# LOCALIZATION NOTE (pasteEventsOnly): The users is pasting assigned task(s) and
+# meeting(s) - this is used as a affix in pasteNotifyAbout
+pasteItemsOnly=Rydych yn gludo cyfarfodydd ac aseiniad tasgau
+
+# LOCALIZATION NOTE (pasteNotifyAbout): Text displayed if pasting an invitation
+# or assigned task
+# %1$S - pasteEvent* or pasteTask*
+pasteNotifyAbout=%1$S - hoffech chi anfon diweddariad i bawb?
+
+# LOCALIZATION NOTE (pasteAndNotifyLabel): button label used in calendar prompt
+# of the pasted item has attendees
+pasteAndNotifyLabel=Gludo ac anfon nawr
+# LOCALIZATION NOTE (pasteDontNotifyLabel): button label used in calendar prompt
+# of the pasted item has attendees
+pasteDontNotifyLabel=Gludo heb anfon
+
+# LOCALIZATION NOTE (importItemsFailed):
+#    %1$S will be replaced with number of failed items
+#    %2$S will be replaced with last error code / error string
+importItemsFailed=%1$S wedi methu a mewnforio. Y gwall olaf oedd: %2$S
+# LOCALIZATION NOTE (noItemsInCalendarFile2):
+#    %1$S will be replaced with file path
+noItemsInCalendarFile2=Methu mewnforio %1$S. Nid oes unrhyw eitemau y mae modd eu mewnforio yn y ffeil hon.
+
+#spaces needed at the end of the following lines
+eventDescription=Disgrifiad:
+
+unableToRead=Methu darllen o ffeil:
+unableToWrite=Methu ysgrifennu i ffeil:
+defaultFileName=MozillaCalEvents
+HTMLTitle=Calendr Mozilla
+
+# LOCALIZATION NOTE (timezoneError):
+# used for an error message like 'An unknown and undefined timezone was found while reading c:\Mycalendarfile.ics'
+#    %1$S will be replaced with the path to a file
+timezoneError=Cafwyd cylch amser anhysbys ac anniffiniedig wrth ddarllen %1$S.
+
+# LOCALIZATION NOTE (duplicateError):
+#    %1$S will be replaced with number of duplicate items
+#    %2$S will be replaced with a file path pointing to a calendar
+duplicateError=Anwybyddwyd %1$S eitem(au) am eu bod yn bodoli yn y calendr cyrchfan ac yn %2$S.
+
+unableToCreateProvider=Digwyddodd gwall wrth baratoi'r calendr sydd yn %1$S ar gyfer ei ddefnyddio. Ni fydd ar gael.
+
+# Sample: Unknown timezone "USPacific" in "Dentist Appt".  Using the 'floating' local timezone instead: 2008/02/28 14:00:00
+unknownTimezoneInItem=Cylch aser anhysbys "%1$S" yn "%2$S".   Yn cael ei drin fel cylch amser 'amhendant': %3$S
+TimezoneErrorsAlertTitle=Gwallau Cylchoedd Amser
+TimezoneErrorsSeeConsole=Gw. Consol Gwall: Mae cylchoedd amser anhysbys yn cael eu trin fel cylchoedd amser lleol 'amhendant'.
+
+# The following strings are for the prompt to delete/unsubscribe from the calendar
+removeCalendarTitle=Tynnu Calendr
+removeCalendarButtonDelete=Dileu Calendr
+removeCalendarButtonUnsubscribe=Dad-danysgrifio
+
+# LOCALIZATION NOTE (removeCalendarMessageDeleteOrUnsubscribe): Shown for
+# calendar where both deleting and unsubscribing is possible.
+# %1$S:  The name of a calendar
+removeCalendarMessageDeleteOrUnsubscribe=Hoffech chi dynnu calendr "%1$S"? Bydd dad-danysgrifio'n tynnu'r calendr o'r rhestr, bydd dileu hefyd yn dileu'r data'n barhaol.
+
+# LOCALIZATION NOTE (removeCalendarMessageDelete): Shown for calendar where
+# deleting is the only option.
+# %1$S:  The name of a calendar
+removeCalendarMessageDelete=Hoffech chi ddileu calendr "%1$S" yn barhaol?
+
+# LOCALIZATION NOTE (removeCalendarMessageUnsubscribe): Shown for calendar
+# where unsubscribing is the only option.
+# %1$S:  The name of a calendar
+removeCalendarMessageUnsubscribe=Hoffech chi ddad-danysgrifio i galendr "%1$S"?
+
+WeekTitle=Wythnos %1$S
+None=Dim
+
+# Error strings
+## @name UID_NOT_FOUND
+## @loc none
+
+# LOCALIZATION NOTE (tooNewSchemaErrorText):
+#    %1$S will be replaced with the name of the host application, e.g. 'Thunderbird'
+#    %2$S will be replaced with the name of the new copy of the file, e.g. 'local-2020-05-11T21-30-17.sqlite'
+tooNewSchemaErrorText=Nid yw data eich calendr yn gydnaws â'r fersiwn hon o %1$S. Diweddarwyd data'r calendr yn eich proffil gan fersiwn mwy diweddar o %1$S. Mae copi wrth gefn o'r ffeil ddata wedi'i chreu, o'r enw "%2$S". Yn parhau gyda ffeil ddata sydd newydd ei chreu.
+
+# List of events or todos (unifinder)
+eventUntitled=Dim Teitl
+
+# Tooltips of events or todos
+tooltipTitle=Teitl:
+tooltipLocation=Lleoliad:
+# event date, usually an interval, such as
+#  Date: 7:00--8:00 Thu 9 Oct 2011
+#  Date: Thu 9 Oct 2000 -- Fri 10 Oct 2000
+tooltipDate=Dyddiad:
+# event calendar name
+tooltipCalName=Enw'r Calendr:
+# event status: tentative, confirmed, cancelled
+tooltipStatus=Statws:
+# event organizer
+tooltipOrganizer=Trefnydd:
+# task/todo fields
+# start date time, due date time, task priority number, completed date time
+tooltipStart=Cychwyn:
+tooltipDue=Erbyn:
+tooltipPriority=Blaenoriaeth:
+tooltipPercent=% Wedi'i Gwblhau:
+tooltipCompleted=Wedi'i Gwblhau:
+
+# Tooltips for attendees and organizer in event and summary dialog
+
+# LOCALIZATION_NOTE(dialog.tooltip.attendee.combined): tooltip for itip icon in summary/event dialog.
+# Given an attendee loungeexample.org of type room is a mandatory participant and has accepted the
+# invitation, the tooltip would be:
+# lounge@example.org (room) is a required participant. lounge@example.org has confirmed attendance.
+# %1$S - value of dialog.tooltip.attendeeRole2.*
+# %2$S - value of dialog.tooltip.attendeePartStat2.*
+dialog.tooltip.attendee.combined=%1$S %2$S
+
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeRole2.CHAIR): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - value of dialog.tooltip.attendeeUserType2.*
+dialog.tooltip.attendeeRole2.CHAIR=Mae %1$S yn cadeirio'r digwyddiad.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeRole2.NON-PARTICIPANT): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - value of dialog.tooltip.attendeeUserType2.*
+dialog.tooltip.attendeeRole2.NON-PARTICIPANT=Nid yw %1$S yn cymryd rhan.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeRole2.OPT-PARTICIPANT): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - value of dialog.tooltip.attendeeUserType2.*
+dialog.tooltip.attendeeRole2.OPT-PARTICIPANT=Mae'n bosib i %1$S gymryd rhan.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeRole2.REQ-PARTICIPANT): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - value of dialog.tooltip.attendeeUserType2.*
+dialog.tooltip.attendeeRole2.REQ-PARTICIPANT=Mae'n angenrheidiol i %1$S gymryd rhan.
+
+# LOCALIZATION_NOTE(dialog.tooltip.attendeePartStat2.ACCEPTED): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - common name or email address of the attendee
+dialog.tooltip.attendeePartStat2.ACCEPTED=Mae %1$S wedi cadarnhau y bydd yn bresennol.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeePartStat2.DECLINED): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - common name or email address of the attendee
+dialog.tooltip.attendeePartStat2.DECLINED=Ni fydd %1$S yn bresennol.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeePartStat2.DELEGATED): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - common name or email address of the attendee
+dialog.tooltip.attendeePartStat2.DELEGATED=Mae %1$S wedi dirprwyo presenoldeb.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeePartStat2.NEEDS-ACTION): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - common name or email address of the attendee
+dialog.tooltip.attendeePartStat2.NEEDS-ACTION=Mae %1$S dal angen ateb.
+# LOCALIZATION_NOTE(dialog.tooltip.attendeePartStat2.TENTATIVE): used to compose
+# dialog.tooltip.attendee.combined
+# %1$S - common name or email address of the attendee
+dialog.tooltip.attendeePartStat2.TENTATIVE=Mae %1$S wedi cadarnhau presenoldeb yn amodol.
+
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeUserType2.INDIVIDUAL): used to compose
+# dialog.tooltip.attendeeRole2.*
+# %1$S - email address or common name <email address> representing individual attendee
+dialog.tooltip.attendeeUserType2.INDIVIDUAL=%1$S
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeUserType2.GROUP): used to compose
+# dialog.tooltip.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a group (e.g. a distribution list)
+dialog.tooltip.attendeeUserType2.GROUP=%1$S (grŵp)
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeUserType2.RESOURCE): used to compose
+# dialog.tooltip.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a resource (e.g. projector)
+dialog.tooltip.attendeeUserType2.RESOURCE=%1$S (adnodd)
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeUserType2.ROOM): used to compose
+# dialog.tooltip.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a room
+dialog.tooltip.attendeeUserType2.ROOM=%1$S (ystafell)
+# LOCALIZATION_NOTE(dialog.tooltip.attendeeUserType2.UNKNOWN): used to compose
+# dialog.tooltip.attendeeRole2.*
+# %1$S - email address or common name <email address> representing an attendee of unknown type
+dialog.tooltip.attendeeUserType2.UNKNOWN=%1$S
+
+#File commands and dialogs
+New=Newydd
+Open=Agor
+filepickerTitleImport=Mewnforio
+filepickerTitleExport=Allforio
+
+# Filters for export/import/open file picker.  %1$S will be replaced with
+# wildmat used to filter files by extension, such as (*.html; *.htm).
+filterIcs=iCalendar (%1$S)
+filterXml=Dogfen XML (%1$S)
+filterHtml=Tudalen Gwe (%1$S)
+filterOutlookCsv=Gwerthoedd Coma Gwahanedig Outlook (%1$S)
+
+# Remote calendar errors
+genericErrorTitle=Digwyddodd gwall
+httpPutError=Methodd cyhoeddi'r ffeil calendr.\nStatws cod: %1$S: %2$S
+otherPutError=Methodd cyhoeddi ffeil calendr.\nStatws cod: 0x%1$S
+
+# LOCALIZATION NOTE (readOnlyMode):
+# used for an message like 'There has been an error reading data for calendar: Home. It has been...'
+#    %1$S will be replaced with the name of a calendar
+readOnlyMode=Bu gwall wrth ddarllen data ar gyfer y calendr: %1$S. Mae wedi'i osod ym modd darllen yn unig, gan fod newidiadau i'r calendr yn debygol o arwain at golli data.  Mae modd newid y gosodiad drwy ddewis 'Golygu Calendr'.
+
+# LOCALIZATION NOTE (disabledMode):
+# used for an message like 'There has been an error reading data for calendar: Home. It has been...'
+#    %1$S will be replaced with the name of a calendar
+disabledMode=Bu gwall wrth ddarllen data ar gyfer y calendr: %1$S. Mae wedi'i analluogi nes ei fod yn ddiogel ei ddefnyddio.
+
+# LOCALIZATION NOTE (minorError):
+# used for an message like 'There has been an error reading data for calendar: Home. However this...'
+#    %1$S will be replaced with the name of a calendar
+minorError=Bu gwall wrth ddarllen data ar gyfer y calendr: %1$S.  Gan fod y gwall yn debygol o fod yn un bychan, bydd y rhaglen yn ceisio parhau.
+
+# LOCALIZATION NOTE (stillReadOnlyError):
+# used for an message like 'There has been an error reading data for calendar: Home.'
+#    %1$S will be replaced with the name of a calendar
+stillReadOnlyError=Bu gwall wrth ddarllen data ar gyfer y calendr: %1$S.
+utf8DecodeError=Bu gwall wrth geisio dadgodio ffeil iCalendr (ics) fel UTF-8. Gwiriwch fod y ffeil, gan gynnwys symbolau a nodau gydag acenion, wedi'i hamgodio gan ddefnyddio amgodiad nod UTF-8.
+icsMalformedError=Methodd didoli ffeil iCalendr (ics). Gwiriwch fod y ffeil yn cyd-fynd â chystrawen ffeil iCalendr (ics).
+itemModifiedOnServerTitle=Eitem wedi newid ar y gweinydd
+itemModifiedOnServer=Mae'r eitem wedi newid yn ddiweddar ar y gweinydd.\n
+modifyWillLoseData=Bydd cyflwyno newidiadau yn tros-ysgrifennu newidiadau sydd wedi'u gwneud ar y gweinydd.
+deleteWillLoseData=Bydd dileu'r eitem yn achosi colli'r newidiadau ar y gweinydd.
+updateFromServer=Hepgor fy newidiadau ac ail-lwytho
+proceedModify=Cyflwyno fy newidiadau beth bynnag
+proceedDelete=Dileu beth bynnag
+dav_notDav=Mae'r adnodd yn %1$S un ai ddim yn gasgliad DAV neu nid yw ar gael
+dav_davNotCaldav=Mae'r adnodd yn %1$S yn gasgliad DAV ond nid yw'n galendr CalDAV
+itemPutError=Bu gwall wrth gadw'r eitem ar y gweinydd.
+itemDeleteError=Bu gwall wrth ddileu'r eitem o'r gweinydd.
+caldavRequestError=Digwyddodd gwall wrth anfon gwahoddiad.
+caldavResponseError=Digwyddodd gwall wrth anfon yr ymateb.
+caldavRequestStatusCode=Cod Statws: %1$S
+caldavRequestStatusCodeStringGeneric=Nid oes modd prosesu'r cais.
+caldavRequestStatusCodeString400=Mae'r cais yn cynnwys cystrawen gwael ac nid oes modd ei brosesu.
+caldavRequestStatusCodeString403=Nid oes gan y defnyddiwr ganiatâd digonol i gyflawni'r cais.
+caldavRequestStatusCodeString404=Heb ganfod yr adnodd.
+caldavRequestStatusCodeString409=Gwrthdaro adnodd.
+caldavRequestStatusCodeString412=Methodd y rhag-amod.
+caldavRequestStatusCodeString500=Gwall mewnol gweinydd.
+caldavRequestStatusCodeString502=Porth gwael (Ffurfweddiad dirprwy?).
+caldavRequestStatusCodeString503=Gwall mewnol gweinydd (Methiant gweinydd dros dro?).
+caldavRedirectTitle=Diweddaru'r lleoliad ar gyfer calendr %1$S?
+caldavRedirectText=Mae'r ceisiadau am %1$S yn cael eu hailgyfeirio i leoliad newydd. Hoffech chi newid y lleoliad i'r gwerth canlynol?
+caldavRedirectDisableCalendar=Analluogi'r Calendr
+
+
+# LOCALIZATION NOTE (likelyTimezone):
+#   Translators, please put the most likely timezone(s) where the people using
+#   your locale will be.  Use the Olson ZoneInfo timezone name *in English*,
+#   ie "Europe/Paris", (continent or ocean)/(largest city in timezone).
+#   Order does not matter, except if two historically different zones now match,
+#   such as America/New_York and America/Toronto, will only find first listed.
+#   (Particularly needed to guess the most relevant timezones if there are
+#    similar timezones at the same June/December GMT offsets with alphabetically
+#    earlier ZoneInfo timezone names.  Sample explanations for English below.)
+# for english-US:
+#   America/Los_Angeles likelier than America/Dawson
+#   America/New_York    likelier than America/Detroit (NY for US-EasternTime)
+# for english:
+#   Europe/London   likelier than Atlantic/Canary
+#   Europe/Paris    likelier than Africa/Ceuta (for WestEuropeanTime)
+#   America/Halifax likelier than America/Glace_Bay (Canada-AtlanticTime)
+#   America/Mexico_City likelier than America/Cancun
+#   America/Argentina/Buenos_Aires likelier than America/Araguaina
+#   America/Sao_Paolo (may not recognize: summer-time dates change every year)
+#   Asia/Singapore  likelier than Antarctica/Casey
+#   Asia/Tokyo      likelier than Asia/Dili
+#   Africa/Lagos likelier than Africa/Algiers (for WestAfricanTime)
+#   Africa/Johannesburg likelier than Africa/Blantyre (for SouthAfricanStdTime)
+#   Africa/Nairobi likelier than Africa/Addis_Ababa (for EastAfricanTime)
+#   Australia/Brisbane likelier than Antarctica/DumontDUrville
+#   Australia/Sydney likelier than Australia/Currie or Australia/Hobart
+#   Pacific/Auckland likelier than Antarctica/McMurdo
+likelyTimezone=America/Efrog Newydd, America/Chicago, America/Denver, America/Phoenix, America/Los_Angeles, America/Anchorage, America/Adak, Pacific/Honolulu, America/Puerto_Rico, America/Halifax, America/Dinas_Mecsico, America/Argentina/Buenos_Aires, America/Sao_Paulo, Ewrop/Llundain, Ewrop/Paris, Asia/Singapore, Asia/Tokyo, Affrica/Lagos, Affrica/Johannesburg, Affrica/Nairobi, Awstralia/Brisbane, Awstralia/Sydney, Môr Tawel/Auckland
+
+# Guessed Timezone errors and warnings.
+# Testing note:
+# * remove preference for calendar.timezone.default in userprofile/prefs.js
+# * repeat
+#   - set OS timezone to a city (windows: click right on clock in taskbar)
+#   - restart
+#   - observe guess in error console and verify whether guessed timezone city
+#     makes sense for OS city.
+#
+# 'Warning: Operating system timezone "E. South America Standard Time"
+#  no longer matches ZoneInfo timezone "America/Sao_Paulo".'
+# Testing notes:
+# - Brasil DST change dates are set every year by decree, so likely out of sync.
+# - Only appears on OSes from which timezone can be obtained
+#   (windows; or TZ env var, /etc/localtime target path, or line in
+#    /etc/timezone or /etc/sysconfig/clock contains ZoneInfo timezone id).
+# - Windows: turning off "Automatically adjust clock for daylight saving time"
+#   can also trigger this warning.
+WarningOSTZNoMatch=Rhybudd: Nid yw cylch amser y system weithredu "%1$S"\n yn cydfynd bellach â'r cylch amser ZoneInfo mewnol "%2$S".
+
+# "Skipping Operating System timezone 'Pacific/New_Country'."
+# Testing note: not easily testable.  May occur someday if (non-windows)
+# OS uses different version of ZoneInfo database which has a timezone name
+# that is not included in our current ZoneInfo database (or if the mapping
+# mapping from windows to ZoneInfo timezone ids does).
+SkippingOSTimezone=Hepgor cylch amser y System Weithredu '%1$S'.
+
+# "Skipping locale timezone 'America/New_Yawk'."
+# Testing note: Skipping occurs if a likelyTimezone id is unknown or misspelled.
+SkippingLocaleTimezone=Hepgor cylch amser y locale '%1$S'.
+
+# Testing note: "No match" timezones include Bucharest on W2k.
+# Brazil timezones may be "No match" (change every year, so often out of date,
+# and changes are often more than a week different).
+warningUsingFloatingTZNoMatch=Rhybudd: Defnyddio cylch amser "amhendant".\nNid oes data cylch amser ZoneInfo ar gael sy'n cyd-fynd â data cylch amser y system weithredu.
+
+# "Warning:  Using guessed timezone
+#    America/New York (UTC-0500/-0400).
+#    [rfc2445 summer daylight saving shift rules for timezone]
+#  This ZoneInfo timezone almost matches/seems to match..."
+#  This ZoneInfo timezone was chosen based on ... "
+WarningUsingGuessedTZ=Rhybudd:  Wedi dyfalu y cylch amser\n  %1$S (UTC%2$S).\n%3$S\n%4$S
+
+# Testing note: "Almost match" timezones include Cairo on W2k.
+TZAlmostMatchesOSDifferAtMostAWeek=Mae'r cylch amser ZoneInfo bron yn cyd-fynd â chylch amser y system weithredu.\nAr gyfer y rheol hwn mae'r trawsnewid rhwng oriau golau dydd ac amser safonol yn\namrywio dim mwy nag wythnos o drawsnewidiad cylch amser y system weithredu.\nEfallai bydd gwahaniaeth yn y data, megis dyddiad cychwyn gwahanol,\nneu reol gwahanol, neu frasamcanu rheol calendr heblaw rhai Georgaidd.
+
+TZSeemsToMatchOS=Mae'r ZoneInfo'r cylch amser i weld yn cyd-fynd â chylch amser y system weithredu eleni.
+
+# LOCALIZATION NOTE (TZFromOS):
+# used for a display of a chosen timezone
+#    %1$S will be replaced with the name of a timezone
+TZFromOS=Dewiswyd y cylch amser ZoneInfo ar sail dynodydd cylch amser y system\nweithredu "%1$S".
+
+# Localization note (TZFromLocale): Substitute name of your locale language.
+TZFromLocale=Mae'r cylch amser ZoneInfo yma wedi'i ddewis drwy gymharu cylch amser y system\nweithredu gyda'r cylchoedd amser tebygol ar gyfer defnyddwyr Saesneg UDA.
+
+TZFromKnownTimezones=Mae'r cylch amser ZoneInfo yma wedi ei ddewis drwy gymharu cylch amser y system\n weithredu gyda'r cylchoedd amser sydd â chylchoedd amser yn ôl trefn yr wyddor.
+
+# Print Layout
+formatListName = Rhestr
+weekPrinterName = Cynllunydd Wythnos
+monthPrinterName = Grid Misol
+tasksWithNoDueDate = Tasgau heb ddyddiad gorffen
+
+# Providers
+caldavName=CalDAV
+compositeName=Cyfansawdd
+icsName=iCalendar (ICS)
+memoryName=Dros dro (cof)
+storageName=Lleol (SQLite)
+
+# Used in created html code for list layout print and html export
+htmlPrefixTitle=Teitl
+htmlPrefixWhen=Pryd
+htmlPrefixLocation=Lleoliad
+htmlPrefixDescription=Disgrifiad
+htmlTaskCompleted=%1$S (cwblhawyd)
+
+# Categories
+addCategory=Ychwanegu Categori
+multipleCategories=Categorïau Lluosog
+
+today=Heddiw
+tomorrow=Yory
+yesterday=Ddoe
+
+#Today pane
+eventsonly=Digwyddiadau
+eventsandtasks=Digwyddiadau a Thasgau
+tasksonly=Tasgau
+shortcalendarweek=CW
+
+go=Mynd
+
+# Some languages have different conjugations of 'next' and 'last'.  If yours
+# does not, simply repeat the value.  This will be used with day names, as in
+# 'next Sunday'.
+next1=nesaf
+next2=nesaf
+last1=olaf
+last2=olaf
+
+# Alarm Dialog
+# LOCALIZATION NOTE (alarmWindowTitle.label): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/Localization_and_Plurals
+alarmWindowTitle.label=Dim Atgoffwrwyr;#1 Atgoffwr;#1 Atgoffwr;#1 Atgoffwr;#1 Atgoffwr;#1 Atgoffwr
+
+# LOCALIZATION NOTE (alarmStarts):
+# used for a display the start of an alarm like 'Starts:  Thu 2 Oct 2008 13:21'
+#    %1$S will be replaced with a date-time
+alarmStarts=Yn Cychwyn: %1$S
+
+# LOCALIZATION NOTE (alarmTodayAt):
+# used for a display the date-time of an alarm like 'Today at Thu 2 Oct 2008 13:21'
+#    %1$S will be replaced with a date-time
+alarmTodayAt=Heddiw am %1$S
+
+# LOCALIZATION NOTE (alarmTomorrowAt):
+# used for a display the date-time of an alarm like 'Tomorrow at Thu 2 Oct 2008 13:21'
+#    %1$S will be replaced with a date-time
+alarmTomorrowAt=Yfory am %1$S
+
+# LOCALIZATION NOTE (alarmYesterdayAt):
+# used for a display the date-time of an alarm like 'Yesterday at Thu 2 Oct 2008 13:21'
+#    %1$S will be replaced with a date-time
+alarmYesterdayAt=Yfory am %1$S
+
+# Alarm interface strings
+# LOCALIZATION NOTE: These strings do not get displayed. They are only visible
+# when exporting an item with i.e a DISPLAY alarm, that doesn't have a
+# description set, or an EMAIL alarm that doesn't have a summary set.
+alarmDefaultDescription=Disgrifiad Mozilla Rhagosodedig
+alarmDefaultSummary=Crynodeb Mozilla Rhagosodedig
+
+# LOCALIZATION NOTE (alarmSnoozeLimitExceeded): Semi-colon list of plural
+# forms.
+alarmSnoozeLimitExceeded=Nid oes modd i chi huno larwm am fwy nag #1 mis.;Nid oes modd i chi huno larwm am fwy na #1 mis.
+
+taskDetailsStatusNeedsAction=Angen Gweithredu
+
+# LOCALIZATION NOTE (taskDetailsStatusInProgress):
+# used for a display of how much of a task is completed '25% Complete'
+#    %1$S will be replaced with the number of percentage completed
+taskDetailsStatusInProgress=Wedi Cwblhau %1$S%%
+taskDetailsStatusCompleted=Cwblhawyd
+
+# LOCALIZATION NOTE (taskDetailsStatusCompletedOn):
+# used for a display of completion date like 'Completed on Thu 2 Oct 2008 13:21'
+#    %1$S will be replaced with the completion date-time of the task
+taskDetailsStatusCompletedOn=Wedi Cwblhau ar %1$S
+taskDetailsStatusCancelled=Diddymwyd
+
+gettingCalendarInfoCommon=Gwirio Calendrau…
+
+# LOCALIZATION NOTE (gettingCalendarInfoDetail):
+# used for a progress-display of processed like 'Checking Calendar 5 of 10'
+#    %1$S will be replaced with the index of the currently processed calendar
+#    %2$S will be replaced with the total numbers of calendars
+gettingCalendarInfoDetail=Gwirio Calendr %1$S o %2$S
+
+# LOCALIZATION NOTE (errorCode):
+#    %1$S will be replaced with the number of an error code
+errorCode=Cod gwall: %1$S
+
+# LOCALIZATION NOTE (errorDescription):
+#    %1$S will be replaced with the description of an error
+errorDescription=Disgrifiad: %1$S
+
+# LOCALIZATION NOTE (errorWriting):
+# used for an message like 'An error occurred when writing to the calendar Home!'
+#    %1$S will be replaced with the name of a calendar
+errorWriting2=Digwyddodd gwall wrth ysgrifennu i galendr %1$S! Gwelwch isod am ragor o wybodaeth.
+
+# LOCALIZATION NOTE (errorWritingDetails):
+# This will be displayed in the detail section of the error dialog
+errorWritingDetails=Os ydych y gweld y neges hon ar ôl cysgu neu gau atgoffwr ac mae hwn yn galendr nad ydych eisiau ychwanegu na golygu digwyddiadau iddo, gallwch nodi'r calendr fel un darllen yn unig er mwyn osgoi profiadau o'r fath yn y dyfodol. I wneud hynny, ewch i briodoleddau'r calendr drwy roi clic de i'r calendr yma yn y rhestr yn y golwg calendr neu dasg.
+
+# LOCALIZATION NOTE (tooltipCalendarDisabled):
+# used for an alert-message like 'The calendar Home is momentarily not available'
+#    %1$S will be replaced with the name of a calendar
+tooltipCalendarDisabled=Nid yw calendr %1$S ar gael ar hyn o bryd
+
+# LOCALIZATION NOTE (tooltipCalendarReadOnly):
+# used for an message like 'The calendar Home is readonly'
+#    %1$S will be replaced with the name of a calendar
+tooltipCalendarReadOnly=Darllen yn unig yw calendr %1$S
+
+taskEditInstructions=Cliciwch yma i ychwanegu tasg newydd
+taskEditInstructionsReadonly=Dewiswch galendr ysgrifenadwy
+taskEditInstructionsCapability=Dewiswch galendr sy'n cynnal tasgau
+
+eventDetailsStartDate=Cychwyn:
+eventDetailsEndDate=Gorffen:
+
+# LOCALIZATION NOTE (datetimeWithTimezone):
+# used for a display of a date-time with timezone 'Thu 2 Oct 2008 13:21', Europe/Paris
+#    %1$S will be replaced with the completion date-time
+#    %2$S will be replaced with the name of the timezone
+datetimeWithTimezone=%1$S, %2$S
+
+# LOCALIZATION NOTE (singleLongCalendarWeek):
+# used for display of calendar weeks in short form like 'Calendar Week 43'
+#    %1$S will be replaced with the index of the week
+singleLongCalendarWeek=Wythnos Calendr: %1$S
+
+# LOCALIZATION NOTE (severalLongCalendarWeeks):
+# used for display of calendar weeks in short form like 'Calendar Weeks 43 - 45'
+#    %1$S will be replaced with the index of the start-week
+#    %2$S will be replaced with the index of the end-week
+severalLongCalendarWeeks=Wythnos Calendr: %1$S-%2$S
+
+# LOCALIZATION NOTE (singleShortCalendarWeek):
+# used for display of calendar weeks in short form like 'CW 43'
+#    %1$S will be replaced with the index of the week
+singleShortCalendarWeek=WC: %1$S
+
+# LOCALIZATION NOTE (severalShortCalendarWeeks):
+# used for display of calendar weeks in short form like 'CWs 43 - 45'
+#    %1$S will be replaced with the index of the start-week
+#    %2$S will be replaced with the index of the end-week
+severalShortCalendarWeeks=WC: %1$S-%2$S
+
+# LOCALIZATION NOTE (abbreviationOfWeek):
+# Used for displaying the week number in the first day box of every week
+# in multiweek and month views.
+# It allows to localize the label with the week number in case your locale
+# requires it.
+# Take into account that this label is placed in the same room of the day label
+# inside the day boxes, exactly on left side, hence a possible string shouldn't
+# be too long otherwise it will create confusion between the week number and
+# the day number other than a possible crop when the window is resized.
+#
+#    %1$S is a number from 1 to 53 that represents the week number.
+abbreviationOfWeek=%1$S
+
+# Task tree, "Due In" column.
+# LOCALIZATION NOTE (dueInDays, dueInHours): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/Localization_and_Plurals
+dueInDays=Dim dyddiau;#1 diwrnod;#1 diwrnod;#1 diwrnod;#1 diwrnod;#1 diwrnod
+dueInHours=#1 awr;#1 awr
+dueInLessThanOneHour=< 1 awr
+
+# LOCALIZATION NOTE (monthInYear):
+# used for display of Month-dates like 'December 2008'
+#    %1$S will be replaced with name of the month
+#    %2$S will be replaced with the year
+monthInYear=%1$S %2$S
+
+# LOCALIZATION NOTE (monthInYear.monthFormat):
+# If your language requires a different declension, change this to 
+# one of the values specified in dateFormat.properties.
+# In any case, DO NOT TRANSLATE.
+monthInYear.monthFormat=nominative
+
+# LOCALIZATION NOTE (formatDateLong):
+# used for display dates in long format like 'Mon 15 Oct 2008' when it's
+# impossible to retrieve the formatatted date from the OS.
+#    %1$S will be replaced with name of the day in short format;
+#    %2$S will be replaced with the day-index of the month, possibly followed by an ordinal symbol
+#         (depending on the string dayOrdinalSymbol in dateFormat.properties);
+#    %3$S will be replaced with the name of the month in short format;
+#    %4$S will be replaced with the year.
+formatDateLong=%1$S %2$S %3$S %4$S
+
+# LOCALIZATION NOTE (dayHeaderLabel):
+# used for display the labels in the header of the days in day/week views in short
+# or long format. For example: 'Monday 6 Oct.' or 'Mon. 6 Oct.'
+#    %1$S will be replaced with name of the day in short or long format
+#    %2$S will be replaced with the day-index of the month, possibly followed by an ordinal symbol
+#         (depending on the string dayOrdinalSymbol in dateFormat.properties), plus the name
+#         of the month in short format (the day/month order depends on the OS settings).
+dayHeaderLabel=%1$S %2$S
+
+# LOCALIZATION NOTE (daysIntervalInMonth):
+# used for display of intervals in the form of 'March 3 - 9, 2008'
+#    %1$S will be replaced with name of the month of the start date
+#    %2$S will be replaced with the day-index of the start date possibly followed by an ordinal symbol
+#    %3$S will be replaced with the day-index of the end date possibly followed by an ordinal symbol
+#    %4$S will be replaced with the common year of both dates
+# The presence of the ordinal symbol in the day-indexes depends on the string
+# dayOrdinalSymbol in dateFormat.properties
+daysIntervalInMonth=%1$S %2$S – %3$S, %4$S
+
+# LOCALIZATION NOTE (daysIntervalInMonth.monthFormat):
+# If your language requires a different declension, change this to
+# one of the values specified in dateFormat.properties.
+# In any case, DO NOT TRANSLATE.
+daysIntervalInMonth.monthFormat=nominative
+
+# LOCALIZATION NOTE (daysIntervalBetweenMonths):
+# used for display of intervals in the form 'September 29 - October 5, 2008'
+#    %1$S will be replaced with name of the month of the start date
+#    %2$S will be replaced with the day-index of the start date possibly followed by an ordinal symbol
+#    %3$S will be replaced with name of the month of the end date
+#    %4$S will be replaced with the day-index of the end date possibly followed by an ordinal symbol
+#    %5$S will be replaced with the common year of both dates
+# The presence of the ordinal symbol in the day-indexes depends on the string
+# dayOrdinalSymbol in dateFormat.properties
+daysIntervalBetweenMonths=%1$S %2$S – %3$S %4$S, %5$S
+
+# LOCALIZATION NOTE (daysIntervalBetweenMonths.monthFormat):
+# If your language requires a different declension, change this to 
+# one of the values specified in dateFormat.properties.
+# In any case, DO NOT TRANSLATE.
+daysIntervalBetweenMonths.monthFormat=nominative
+
+# LOCALIZATION NOTE (daysIntervalBetweenYears):
+# used for display of intervals in the form 'December 29, 2008 - January 4, 2009'
+#    %1$S will be replaced with name of the month of the start date
+#    %2$S will be replaced with the day-index of the start date possibly followed by an ordinal symbol
+#    %3$S will be replaced with the year of the start date
+#    %4$S will be replaced with name of the month of the end date
+#    %5$S will be replaced with the day-index of the end date possibly followed by an ordinal symbol
+#    %6$S will be replaced with the year of the end date
+# The presence of the ordinal symbol in the day-indexes depends on the string
+# dayOrdinalSymbol in dateFormat.properties
+daysIntervalBetweenYears=%1$S %2$S, %3$S – %4$S %5$S, %6$S
+
+# LOCALIZATION NOTE (daysIntervalBetweenYears.monthFormat):
+# If your language requires a different declension, change this to
+# one of the values specified in dateFormat.properties.
+# In any case, DO NOT TRANSLATE.
+daysIntervalBetweenYears.monthFormat=nominative
+
+# LOCALIZATION NOTE (datetimeIntervalOnSameDateTime):
+# used for intervals where end is equals to start
+# displayed form is '5 Jan 2006 13:00'
+#    %1$S will be replaced with the date of the start date
+#    %2$S will be replaced with the time of the start date
+datetimeIntervalOnSameDateTime=%1$S %2$S
+
+# LOCALIZATION NOTE (datetimeIntervalOnSameDay):
+# used for intervals where end is on the same day as start, so we can leave out the
+# end date but still include end time
+# displayed form is '5 Jan 2006 13:00 - 17:00'
+#    %1$S will be replaced with the date of the start date
+#    %2$S will be replaced with the time of the start date
+#    %3$S will be replaced with the time of the end date
+datetimeIntervalOnSameDay=%1$S %2$S – %3$S
+
+# LOCALIZATION NOTE (datetimeIntervalOnSeveralDays):
+# used for intervals spanning multiple days by including date and time
+# displayed form is '5 Jan 2006 13:00 - 7 Jan 2006 9:00'
+#    %1$S will be replaced with the date of the start date
+#    %2$S will be replaced with the time of the start date
+#    %3$S will be replaced with the date of the end date
+#    %4$S will be replaced with the time of the end date
+datetimeIntervalOnSeveralDays=%1$S %2$S – %3$S %4$S
+
+# LOCALIZATION NOTE (datetimeIntervalTaskWithoutDate):
+# used for task without start and due date
+# (showed only in exported calendar in Html format)
+datetimeIntervalTaskWithoutDate= dim dyddiad cychwyn na gorffen
+# LOCALIZATION NOTE (datetimeIntervalTaskWithoutDueDate):
+# used for intervals in task with only start date
+# displayed form is 'start date 5 Jan 2006 13:00'
+# (showed only in exported calendar in Html format)
+#    %1$S will be replaced with the date of the start date
+#    %2$S will be replaced with the time of the start date
+datetimeIntervalTaskWithoutDueDate=dyddiad cychwyn %1$S %2$S
+# LOCALIZATION NOTE (datetimeIntervalTaskWithoutStartDate):
+# used for intervals in task with only due date
+# displayed form is 'due date 5 Jan 2006 13:00'
+# (showed only in exported calendar in Html format)
+#    %1$S will be replaced with the date of the due date
+#    %2$S will be replaced with the time of the due date
+datetimeIntervalTaskWithoutStartDate=dyddiad gorffen %1$S %2$S
+
+# LOCALIZATION NOTE (dragLabelTasksWithOnlyEntryDate
+#                    dragLabelTasksWithOnlyDueDate)
+# Labels that appear while dragging a task with only
+# entry date OR due date
+dragLabelTasksWithOnlyEntryDate=Amser cychwyn
+dragLabelTasksWithOnlyDueDate=Erbyn
+
+deleteTaskLabel=Dileu Tasg
+deleteTaskMessage=Ydych chi wir eisiau dileu'r Dasg?
+deleteTaskAccesskey=l
+deleteItemLabel=Dileu
+deleteItemMessage=Ydych chi wir eisiau dileu'r Eitem?
+deleteItemAccesskey=D
+deleteEventLabel=Dileu Digwyddiad
+deleteEventMessage=Ydych chi wir eisiau dileu'r Digwyddiad?
+deleteEventAccesskey=i
+
+calendarPropertiesEveryMinute=Pob munud;Pob #1 munud
+
+# LOCALIZATION NOTE (extractUsing)
+# Used in message header
+#    %1$S will be replaced with language name from languageNames.properties
+extractUsing=Defnyddio %1$S
+
+# LOCALIZATION NOTE (extractUsingRegion)
+# Used in message header
+#    %1$S will be replaced with language name from languageNames.properties
+#    %2$S will be replaced with region like US in en-US
+extractUsingRegion=Defnyddio %1$S (%2$S)
+
+# LOCALIZATION NOTE (unit)
+# Used to determine the correct plural form of a unit
+unitMinutes=#1 munud;#1 munud;#1 funud;#1 munud;#1 munud;#1 munud
+unitHours=#1 awr;#1 awr
+unitDays=Dim dyddiau;#1 diwrnod;#1 diwrnod;#1 diwrnod;#1 diwrnod;#1 diwrnod
+unitWeeks=#1 wythnos;#1 wythnos
+
+# LOCALIZATION NOTE (showCalendar)
+# Used in calendar list context menu
+#    %1$S will be replaced with the calendar name
+# uses the access key calendar.context.togglevisible.accesskey
+showCalendar=Dangos %1$S
+hideCalendar=Cuddio %1$S
+# uses the access key calendar.context.showonly.accesskey
+showOnlyCalendar=Dangos Dim Ond %1$S
+
+# LOCALIZATION NOTE (modifyConflict)
+# Used by the event dialog to resolve item modification conflicts.
+modifyConflictPromptTitle=Gwrthdaro Newid Eitem
+modifyConflictPromptMessage=Mae'r eitem s'yn cael ei golygu yn y ddeialog wedi ei newid ers ei hagor.
+modifyConflictPromptButton1=Trosysgrifenu'r newidiadau eraill
+modifyConflictPromptButton2=Hepgor y newidiadau hyn
+
+# LOCALIZATION_NOTE(dialog.attendee.append.delegatedFrom): this is appended behind an attendee name
+# in the tooltip and the visible name for an attendee in the event summary dialog - don't add
+# leading or trailing whitespaces here
+# %1$S - a single delegatee or a comma separated list of delegatees
+# delegation is different from simple invitation forwarding - in case of delegation the original
+# invited attendee gets replaced
+dialog.attendee.append.delegatedFrom=(trosglwyddwyd o %1$S)
+# LOCALIZATION_NOTE(dialog.attendee.append.delegatedTo): this is appended behind an attendee name
+# in the tooltip for an attendee in the event summary dialog - don't add leading or trailing
+# whitespaces here
+# delegation is different from simple invitation forwarding - in case of delegation the original
+# invited attendee gets replaced
+dialog.attendee.append.delegatedTo=(trosglwyddwyd i %1$S)
+
+# Accessible description of a grid calendar with no selected date
+minimonthNoSelectedDate=Dim dyddiad wedi ei ddewis
diff --git a/l10n-cy/calendar/chrome/calendar/calendarCreation.dtd b/l10n-cy/calendar/chrome/calendar/calendarCreation.dtd
new file mode 100644
index 0000000000..253f4e10b9
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendarCreation.dtd
@@ -0,0 +1,51 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY wizard.title             "Creu Calendr Newydd" >
+<!ENTITY wizard.label             "Creu calendr newydd" >
+<!ENTITY wizard.description       "Lleoli eich calendr" >
+
+<!ENTITY initialpage.description    "Mae modd gosod eich calendr ar eich cyfrifiadur neu ar weinydd fel bod modd i chi gael mynediad o bell neu ei rannu gyda'ch ffrindiau a'ch cydweithwyr." >
+<!ENTITY initialpage.computer.label  "Ar Fy Nghyfrifiadur">
+<!ENTITY initialpage.network.label  "Ar y Rhwydwaith">
+
+<!ENTITY locationpage.description         "Darparwch y wybodaeth angenrheidiol ar gyfer cael mynediad at eich calendr pell" >
+<!ENTITY locationpage.login.description   "Dewisol: rhowch enw defnyddiwr a chyfrinair" >
+<!ENTITY locationpage.username.label      "Enw defnyddiwr:" >
+<!ENTITY locationpage.password.label      "Cyfrinair:" >
+
+<!ENTITY custompage.shortdescription  "Cyfaddasu eich calendr" >
+<!ENTITY custompage.longdescription   "Mae modd rhoi enw i'r calendr a lliwio digwyddiadau'r calendr." >
+
+<!ENTITY finishpage.shortdescription  "Crëwyd y Calendr" >
+<!ENTITY finishpage.longdescription   "Mae eich calendr wedi'i greu." >
+
+<!-- Below are new strings for the revised new calendar dialog. The above strings should be
+    removed/renamed later on -->
+
+<!ENTITY sourcetabs.other.label  "Arall">
+
+<!ENTITY buttons.create.label "Creu Calendr">
+<!ENTITY buttons.create.accesskey "r">
+
+<!ENTITY buttons.find.label "Canfod Calendrau">
+<!ENTITY buttons.find.accesskey "f">
+
+<!ENTITY buttons.back.label "Nôl">
+<!ENTITY buttons.back.accesskey "N">
+
+<!ENTITY buttons.subscribe.label "Tanysgrifio">
+<!ENTITY buttons.subscribe.accesskey "T">
+
+<!ENTITY calendartype.label "Math o Galendr:">
+<!ENTITY location.label "Lleoliad:">
+<!ENTITY location.placeholder "URL neu enw gwesteiwr gweinydd y calendr">
+
+<!ENTITY network.nocredentials.label "Nid yw'r lleoliad hwn angen dilysiad">
+<!ENTITY network.loading.description "Arhoswch tra bod eich calendrau yn cael eu darganfod.">
+<!ENTITY network.notfound.description "Heb ganfod calendrau yn y lleoliad hwn. Gwiriwch eich gosodiadau.">
+<!ENTITY network.authfail.description "Nid yw'r manylion rydych wedi'u cynnig wedi eu derbyn. Gwiriwch eich gosodiadau.">
+
+<!ENTITY network.subscribe.single.description "Dewiswch y calendrau'r hoffech danysgrifio iddynt.">
+<!ENTITY network.subscribe.multiple.description "Mae mathau calendr lluosog ar gael; ar gyfer y lleoliad hwn. Dewiswch y math o galendr, yna mario'r calendrau yr hoffech chi danysgrifio iddyn nhw.">
diff --git a/l10n-cy/calendar/chrome/calendar/calendarCreation.properties b/l10n-cy/calendar/chrome/calendar/calendarCreation.properties
new file mode 100644
index 0000000000..3789a54d85
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/calendarCreation.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+error.invalidUri=Rhowch leoliad dilys.
+error.alreadyExists=Rydych eisoes wedi tanysgrifio i galendr yn y lleoliad hwn.
diff --git a/l10n-cy/calendar/chrome/calendar/categories.properties b/l10n-cy/calendar/chrome/calendar/categories.properties
new file mode 100644
index 0000000000..4706d4cb77
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/categories.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# default categories
+
+categories2=Dathliadau,Pen-blwydd,Busnes,Galwadau,Cleientiaid,Cystadleuaeth,Cwsmer,Ffefrynnau,Dilyn,Anrhegion,Gwyliau,Syniadau,Materion,Amrywiol,Personol,Projectau,Gwyliau Cyhoeddus,Statws,Darparwyr,Teithio,Ffrindiau
diff --git a/l10n-cy/calendar/chrome/calendar/dateFormat.properties b/l10n-cy/calendar/chrome/calendar/dateFormat.properties
new file mode 100644
index 0000000000..06fd74182a
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/dateFormat.properties
@@ -0,0 +1,146 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# In case you are looking for the note about different declensions on date
+# formats, here it is. If your language doesn't use different declensions of
+# month names, you shouldn't have much work. Just leave the *.monthFormat
+# string on "nominative" and the string month.*.name will be filled in.
+#
+# If you need a different form for a string, you can change the 
+# *.monthFormat to a different value. Supported values are currently:
+#    nominative (default), genitive
+# The modified month name form will then be filled in accordingly. If this
+# system does not suit your needs, please file a bug!
+
+# LOCALIZATION NOTE (month.*.name):
+# Some languages require different declensions of month names.
+# These values will be used if *.monthFormat is set to "nominative" or in places
+# where using a different declension is not yet supported.
+month.1.name=Ionawr
+month.2.name=Chwefror
+month.3.name=Mawrth
+month.4.name=Ebrill
+month.5.name=Mai
+month.6.name=Mehefin
+month.7.name=Gorffennaf
+month.8.name=Awst
+month.9.name=Medi
+month.10.name=Hydref
+month.11.name=Tachwedd
+month.12.name=Rhagfyr
+
+# LOCALIZATION NOTE (month.*.genitive):
+# Some languages require different declensions of month names.
+# These values will be used if *.monthFormat is set to "genitive"
+# If your language doesn't use different declensions, just set the same
+# values as for month.*.name.
+month.1.genitive=Ionawr
+month.2.genitive=Chwefror
+month.3.genitive=Mawrth
+month.4.genitive=Ebrill
+month.5.genitive=Mai
+month.6.genitive=Mehefin
+month.7.genitive=Gorffennaf
+month.8.genitive=Awst
+month.9.genitive=Medi
+month.10.genitive=Hydref
+month.11.genitive=Tachwedd
+month.12.genitive=Rhagfyr
+
+month.1.Mmm=Ion
+month.2.Mmm=Chw
+month.3.Mmm=Maw
+month.4.Mmm=Ebr
+month.5.Mmm=Mai
+month.6.Mmm=Meh
+month.7.Mmm=Gor
+month.8.Mmm=Aws
+month.9.Mmm=Med
+month.10.Mmm=Hyd
+month.11.Mmm=Tach
+month.12.Mmm=Rha
+
+day.1.name=Dydd Sul
+day.2.name=Dydd Llun
+day.3.name=Dydd Mawrth
+day.4.name=Dydd Mercher
+day.5.name=Dydd Iau
+day.6.name=Dydd Gwener
+day.7.name=Dydd Sadwrn
+
+day.1.Mmm=Sul
+day.2.Mmm=Llu
+day.3.Mmm=Maw
+day.4.Mmm=Mer
+day.5.Mmm=Iau
+day.6.Mmm=Gwe
+day.7.Mmm=Sad
+
+# Can someone tell me why we're not counting from zero?
+day.1.short=Su
+day.2.short=Ll
+day.3.short=Ma
+day.4.short=Me
+day.5.short=Ia
+day.6.short=Gw
+day.7.short=Sa
+
+# Localizable day's date
+day.1.number=1
+day.2.number=2
+day.3.number=3
+day.4.number=4
+day.5.number=5
+day.6.number=6
+day.7.number=7
+day.8.number=8
+day.9.number=9
+day.10.number=10
+day.11.number=11
+day.12.number=12
+day.13.number=13
+day.14.number=14
+day.15.number=15
+day.16.number=16
+day.17.number=17
+day.18.number=18
+day.19.number=19
+day.20.number=20
+day.21.number=21
+day.22.number=22
+day.23.number=23
+day.24.number=24
+day.25.number=25
+day.26.number=26
+day.27.number=27
+day.28.number=28
+day.29.number=29
+day.30.number=30
+day.31.number=31
+
+# LOCALIZATION NOTE (dayOrdinalSymbol):
+# Allows to insert a string, a character or a symbol after the number of a
+# monthday in order to give it the meaning of ordinal number e.g.  1 -> 1st etc.
+# It's mainly used when formatting dates with both monthday and month name. It
+# affects the following localizable strings that hence must be localized *without*
+# any ordinal symbol for the monthday number:
+#   dayHeaderLabel, monthlyDaysOfNth_day,
+#   yearlyNthOn, daysIntervalBetweenYears,
+#   daysIntervalBetweenMonths, daysIntervalInMonth.
+# Write only a single string if the ordinal symbol is the same for every monthday, otherwise
+# write a sequence of _31_ strings (one for each monthday) separated with commas.
+# If your language doesn't require that in the mentioned strings, leave it empty.
+# e.g.
+# dayOrdinalSymbol=.
+#    -> daysIntervalInMonth: 'March 3. - 9., 2008'
+# dayOrdinalSymbol=st,nd,rd,th,th,th,th,th,th,th,th,th,th,th,th,
+#                  th,th,th,th,th,st,nd,rd,th,th,th,th,th,th,th,st
+#    -> daysIntervalBetweenMonths: 'September 29th - November 1st, 2008'
+dayOrdinalSymbol=
+
+noon=Canol Dydd
+midnight=Canol Nos
+
+AllDay=Trwy'r Dydd
+Repeating=(Ailadrodd)
diff --git a/l10n-cy/calendar/chrome/calendar/dialogs/calendar-event-dialog-reminder.dtd b/l10n-cy/calendar/chrome/calendar/dialogs/calendar-event-dialog-reminder.dtd
new file mode 100644
index 0000000000..842271e494
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/dialogs/calendar-event-dialog-reminder.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY reminderdialog.title                              "Gosod Atgoffwyr">
+<!ENTITY reminder.add.label                                "Ychwanegu">
+<!ENTITY reminder.add.accesskey                            "Y">
+<!ENTITY reminder.remove.label                             "Tynnu">
+<!ENTITY reminder.remove.accesskey                         "T">
+
+<!ENTITY reminder.reminderDetails.label                    "Manylion Atgoffwr">
+<!ENTITY reminder.action.label                             "Dewis Gweithred Atgoffa">
+
+<!ENTITY reminder.action.alert.label                       "Dangos Rhybudd">
+<!ENTITY reminder.action.email.label                       "Anfon E-bost">
+
+<!ENTITY alarm.units.minutes                               "munud" >
+<!ENTITY alarm.units.hours                                 "awr" >
+<!ENTITY alarm.units.days                                  "diwrnod" >
diff --git a/l10n-cy/calendar/chrome/calendar/global.dtd b/l10n-cy/calendar/chrome/calendar/global.dtd
new file mode 100644
index 0000000000..61fdb3c2e2
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/global.dtd
@@ -0,0 +1,25 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY month.1.name "Ionawr" >
+<!ENTITY month.2.name "Chwefror" >
+<!ENTITY month.3.name "Mawrth" >
+<!ENTITY month.4.name "Ebrill" >
+<!ENTITY month.5.name "Mai" >
+<!ENTITY month.6.name "Mehefin" >
+<!ENTITY month.7.name "Gorffennaf" >
+<!ENTITY month.8.name "Awst" >
+<!ENTITY month.9.name "Medi" >
+<!ENTITY month.10.name "Hydref" >
+<!ENTITY month.11.name "Tachwedd" >
+<!ENTITY month.12.name "Rhagfyr" >
+
+<!ENTITY onemonthbackward.tooltip "Un Mis Nôl" >
+<!ENTITY onemonthforward.tooltip "Un Mis Ymlaen" >
+<!ENTITY oneyearbackward.tooltip "Nôl Un Flwyddyn" >
+<!ENTITY oneyearforward.tooltip "Ymlaen Un Flwyddyn" >
+<!ENTITY showToday.tooltip "Mynd i Heddiw">
+<!ENTITY onedayforward.tooltip "Ymlaen Un Diwrnod">
+<!ENTITY onedaybackward.tooltip "Nôl Un Diwrnod">
+<!ENTITY showselectedday.tooltip "Dangos digwyddiadau un diwrnod">
diff --git a/l10n-cy/calendar/chrome/calendar/menuOverlay.dtd b/l10n-cy/calendar/chrome/calendar/menuOverlay.dtd
new file mode 100644
index 0000000000..3957e79871
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/menuOverlay.dtd
@@ -0,0 +1,50 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Event Menu -->
+
+<!ENTITY event.new.event                        "Digwyddiad Newydd…">
+<!ENTITY event.new.event.accesskey              "D">
+
+<!ENTITY event.new.task                         "Tasg Newydd…">
+<!ENTITY event.new.task.accesskey               "T">
+
+<!ENTITY calendar.import.label                  "Mewnforio…">
+<!ENTITY calendar.import.accesskey              "M">
+
+<!ENTITY calendar.export.label                  "Allforio…">
+<!ENTITY calendar.export.accesskey              "A">
+
+<!ENTITY calendar.publish.label                 "Cyhoeddi…">
+<!ENTITY calendar.publish.accesskey             "y">
+
+<!ENTITY calendar.deletecalendar.label          "Dileu'r Calendr…">
+<!ENTITY calendar.deletecalendar.accesskey      "i">
+<!ENTITY calendar.unsubscribecalendar.label     "Dad-danysgrifo Calendrau Penodol…">
+<!ENTITY calendar.unsubscribecalendar.accesskey "D">
+<!-- LOCALIZATION NOTE (calendar.removecalendar.label): Removing the calendar
+      is the general action of removing it, while deleting means to clear the
+      data and unsubscribing means just taking it out of the calendar list. -->
+
+<!ENTITY calendar.removecalendar.label          "Tynnu Calendrau Penodol…">
+<!ENTITY calendar.removecalendar.accesskey      "T">
+
+
+<!ENTITY calendar.menu.customize.label          "Cyfaddasu…">
+<!ENTITY calendar.menu.customize.accesskey      "f">
+
+<!ENTITY showUnifinderCmd.label                 "Canfod Digwyddiadau">
+<!ENTITY showUnifinderCmd.accesskey             "f">
+<!ENTITY showUnifinderCmd.tooltip               "Toglo'r paen canfod digwyddiadau">
+
+<!ENTITY calendar.displaytodos.checkbox.label       "Dangos Tasgau yn y Calendr">
+<!ENTITY calendar.displaytodos.checkbox.accesskey   "D">
+
+<!ENTITY goTodayCmd.label                       "Heddiw">
+<!ENTITY goTodayCmd.accesskey                   "H">
+
+<!ENTITY showCurrentView.label                  "Golwg Cyfredol">
+<!ENTITY showCurrentView.accesskey              "G">
+
+<!ENTITY calendar.properties.label              "Priodweddau'r Calendr…">
+<!ENTITY calendar.properties.accesskey          "P">
diff --git a/l10n-cy/calendar/chrome/calendar/migration.dtd b/l10n-cy/calendar/chrome/calendar/migration.dtd
new file mode 100644
index 0000000000..bfe7a6f69e
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/migration.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY migration.title "&brandFullName;: Mewnforio Data">
+<!ENTITY migration.welcome "Croeso">
+<!ENTITY migration.importing "Mewnforio">
+<!ENTITY migration.list.description "Mae &brandShortName; yn gallu mewnforio data calendr o nifer o raglenni poblogaidd. Mae data o'r rhaglenni canlynol wedi'u canfod ar eich cyfrifiadur. Dewiswch o ba un o'r rhain rydych am fewnforio data.">
+<!ENTITY migration.progress.description "Mewnforio data dewiswyd">
diff --git a/l10n-cy/calendar/chrome/calendar/migration.properties b/l10n-cy/calendar/chrome/calendar/migration.properties
new file mode 100644
index 0000000000..830bec0162
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/migration.properties
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+migratingApp = Mudo %1$S…
+
+# The next two lines are duplicated from migration.dtd until there is branding
+# for lightning
+migrationTitle = %1$S: Mewnforio Data
+migrationDescription=Mae %1$S yn gallu mewnforio data calendr o nifer o raglenni poblogaidd. Mae data o'r rhaglenni canlynol wedi'u canfod ar eich cyfrifiadur. Dewiswch o ba un o'r rhain yr hoffech fewnforio data.
+finished = Cwblhawyd
diff --git a/l10n-cy/calendar/chrome/calendar/provider-uninstall.dtd b/l10n-cy/calendar/chrome/calendar/provider-uninstall.dtd
new file mode 100644
index 0000000000..c7211dc306
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/provider-uninstall.dtd
@@ -0,0 +1,12 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY providerUninstall.title                           "Dadosod Darparwr">
+<!ENTITY providerUninstall.accept.label                    "Dad-danysgrifio o'r Dewis">
+<!ENTITY providerUninstall.accept.accesskey                "D">
+<!ENTITY providerUninstall.cancel.label                    "Cadw'r Ychwanegyn">
+<!ENTITY providerUninstall.cancel.accesskey                "Y">
+<!ENTITY providerUninstall.preName.label                   "Rydych wedi gofyn i ddadosod neu analluogi:">
+<!ENTITY providerUninstall.postName.label                  "Bydd hyn yn achosi i'r calendrau isod gael eu hanalluogi.">
+<!ENTITY providerUninstall.reinstallNote.label             "Oni bai eich bod yn cynllunio i ailosod y darparwr, gallwch ddewis i ddad-danysgrifio o galendrau'r darparwr.">
diff --git a/l10n-cy/calendar/chrome/calendar/timezones.properties b/l10n-cy/calendar/chrome/calendar/timezones.properties
new file mode 100644
index 0000000000..2af51fa1f6
--- /dev/null
+++ b/l10n-cy/calendar/chrome/calendar/timezones.properties
@@ -0,0 +1,488 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# extension:
+extensions.calendar-timezones@mozilla.org.name=Diffiniadau Cylchoedd Amser Calendr Mozilla
+extensions.calendar-timezones@mozilla.org.description=Diffiniadau cylch amser ar gyfer Lightning
+extensions.calendar-timezones@mozilla.org.creator=Project Calendr Mozilla
+
+pref.timezone.floating=Amser Lleol
+pref.timezone.UTC=UTC/GMT
+
+# I've derived this list out of timezones.dtd
+# - replaced '_' with ' ' on value side
+# - corrected 'St xyz' to 'St. xyz'
+
+# timezone names:
+pref.timezone.Africa.Abidjan=Affrica/Abidjan
+pref.timezone.Africa.Accra=Affrica/Accra
+pref.timezone.Africa.Addis_Ababa=Affrica/Addis Ababa
+pref.timezone.Africa.Algiers=Affrica/Algiers
+pref.timezone.Africa.Asmara=Affrica/Asmara
+pref.timezone.Africa.Bamako=Affrica/Bamako
+pref.timezone.Africa.Bangui=Affrica/Bangui
+pref.timezone.Africa.Banjul=Affrica/Banjul
+pref.timezone.Africa.Bissau=Affrica/Bissau
+pref.timezone.Africa.Blantyre=Affrica/Blantyre
+pref.timezone.Africa.Brazzaville=Affrica/Brazzaville
+pref.timezone.Africa.Bujumbura=Affrica/Bujumbura
+pref.timezone.Africa.Cairo=Affrica/Cairo
+pref.timezone.Africa.Casablanca=Affrica/Casablanca
+pref.timezone.Africa.Ceuta=Affrica/Ceuta
+pref.timezone.Africa.Conakry=Affrica/Conakry
+pref.timezone.Africa.Dakar=Affrica/Dakar
+pref.timezone.Africa.Dar_es_Salaam=Affrica/Dar es Salaam
+pref.timezone.Africa.Djibouti=Affrica/Djibouti
+pref.timezone.Africa.Douala=Affrica/Douala
+pref.timezone.Africa.El_Aaiun=Affrica/El Aaiun
+pref.timezone.Africa.Freetown=Affrica/Freetown
+pref.timezone.Africa.Gaborone=Affrica/Gaborone
+pref.timezone.Africa.Harare=Affrica/Harare
+pref.timezone.Africa.Johannesburg=Affrica/Johannesburg
+pref.timezone.Africa.Kampala=Affrica/Kampala
+pref.timezone.Africa.Khartoum=Affrica/Khartoum
+pref.timezone.Africa.Kigali=Affrica/Kigali
+pref.timezone.Africa.Kinshasa=Affrica/Kinshasa
+pref.timezone.Africa.Lagos=Affrica/Lagos
+pref.timezone.Africa.Libreville=Affrica/Libreville
+pref.timezone.Africa.Lome=Affrica/Lome
+pref.timezone.Africa.Luanda=Affrica/Luanda
+pref.timezone.Africa.Lubumbashi=Affrica/Lubumbashi
+pref.timezone.Africa.Lusaka=Affrica/Lusaka
+pref.timezone.Africa.Malabo=Affrica/Malabo
+pref.timezone.Africa.Maputo=Affrica/Maputo
+pref.timezone.Africa.Maseru=Affrica/Maseru
+pref.timezone.Africa.Mbabane=Affrica/Mbabane
+pref.timezone.Africa.Mogadishu=Affrica/Mogadishu
+pref.timezone.Africa.Monrovia=Affrica/Monrovia
+pref.timezone.Africa.Nairobi=Africa/Nairobi
+pref.timezone.Africa.Ndjamena=Affrica/Ndjamena
+pref.timezone.Africa.Niamey=Affrica/Niamey
+pref.timezone.Africa.Nouakchott=Affrica/Nouakchott
+pref.timezone.Africa.Ouagadougou=Affrica/Ouagadougou
+pref.timezone.Africa.Porto-Novo=Affrica/Porto-Novo
+pref.timezone.Africa.Sao_Tome=Affrica/Sao Tome
+pref.timezone.Africa.Tripoli=Affrica/Tripoli
+pref.timezone.Africa.Tunis=Affrica/Tunis
+pref.timezone.Africa.Windhoek=Affrica/Windhoek
+pref.timezone.America.Adak=America/Adak
+pref.timezone.America.Anchorage=America/Anchorage
+pref.timezone.America.Anguilla=America/Anguilla
+pref.timezone.America.Antigua=America/Antigua
+pref.timezone.America.Araguaina=America/Araguaina
+pref.timezone.America.Argentina.Buenos_Aires=America/Yr Arianin/Buenos Aires
+pref.timezone.America.Argentina.Catamarca=America/Yr Arianin/Catamarca
+pref.timezone.America.Argentina.Cordoba=America/Yr Arianin/Cordoba
+pref.timezone.America.Argentina.Jujuy=America/Yr Arianin/Jujuy
+pref.timezone.America.Argentina.La_Rioja=America/Yr Arianin/La Rioja
+pref.timezone.America.Argentina.Mendoza=America/Yr Arianin/Mendoza
+pref.timezone.America.Argentina.Rio_Gallegos=America/Yr Arianin/Rio Gallegos
+pref.timezone.America.Argentina.San_Juan=America/Yr Arianin/San Juan
+pref.timezone.America.Argentina.Tucuman=America/Yr Arianin/Tucuman
+pref.timezone.America.Argentina.Ushuaia=America/Yr Arianin/Ushuaia
+pref.timezone.America.Aruba=America/Aruba
+pref.timezone.America.Asuncion=America/Asuncion
+pref.timezone.America.Atikokan=America/Atikokan
+pref.timezone.America.Bahia=America/Bahia
+pref.timezone.America.Barbados=America/Barbados
+pref.timezone.America.Belem=America/Belem
+pref.timezone.America.Belize=America/Belize
+pref.timezone.America.Blanc-Sablon=America/Blanc-Sablon
+pref.timezone.America.Boa_Vista=America/Boa Vista
+pref.timezone.America.Bogota=America/Bogota
+pref.timezone.America.Boise=America/Boise
+pref.timezone.America.Cambridge_Bay=America/Cambridge Bay
+pref.timezone.America.Campo_Grande=America/Campo Grande
+pref.timezone.America.Cancun=America/Cancun
+pref.timezone.America.Caracas=America/Caracas
+pref.timezone.America.Cayenne=America/Cayenne
+pref.timezone.America.Cayman=America/Cayman
+pref.timezone.America.Chicago=America/Chicago
+pref.timezone.America.Chihuahua=America/Chihuahua
+pref.timezone.America.Costa_Rica=America/Costa Rica
+pref.timezone.America.Cuiaba=America/Cuiaba
+pref.timezone.America.Curacao=America/Curacao
+pref.timezone.America.Danmarkshavn=America/Danmarkshavn
+pref.timezone.America.Dawson=America/Dawson
+pref.timezone.America.Dawson_Creek=America/Dawson Creek
+pref.timezone.America.Denver=America/Denver
+pref.timezone.America.Detroit=America/Detroit
+pref.timezone.America.Dominica=America/Dominica
+pref.timezone.America.Edmonton=America/Edmonton
+pref.timezone.America.Eirunepe=America/Eirunepe
+pref.timezone.America.El_Salvador=America/El Salvador
+pref.timezone.America.Fortaleza=America/Fortaleza
+pref.timezone.America.Glace_Bay=America/Glace Bay
+pref.timezone.America.Godthab=America/Godthab
+pref.timezone.America.Goose_Bay=America/Goose Bay
+pref.timezone.America.Grand_Turk=America/Grand Turk
+pref.timezone.America.Grenada=America/Grenada
+pref.timezone.America.Guadeloupe=America/Guadeloupe
+pref.timezone.America.Guatemala=America/Guatemala
+pref.timezone.America.Guayaquil=America/Guayaquil
+pref.timezone.America.Guyana=America/Guyana
+pref.timezone.America.Halifax=America/Halifax
+pref.timezone.America.Havana=America/Havana
+pref.timezone.America.Hermosillo=America/Hermosillo
+pref.timezone.America.Indiana.Indianapolis=America/Indiana/Indianapolis
+pref.timezone.America.Indiana.Knox=America/Indiana/Knox
+pref.timezone.America.Indiana.Marengo=America/Indiana/Marengo
+pref.timezone.America.Indiana.Petersburg=America/Indiana/Petersburg
+pref.timezone.America.Indiana.Vevay=America/Indiana/Vevay
+pref.timezone.America.Indiana.Vincennes=America/Indiana/Vincennes
+pref.timezone.America.Inuvik=America/Inuvik
+pref.timezone.America.Iqaluit=America/Iqaluit
+pref.timezone.America.Jamaica=America/Jamaica
+pref.timezone.America.Juneau=America/Juneau
+pref.timezone.America.Kentucky.Louisville=America/Kentucky/Louisville
+pref.timezone.America.Kentucky.Monticello=America/Kentucky/Monticello
+pref.timezone.America.La_Paz=America/La Paz
+pref.timezone.America.Lima=America/Lima
+pref.timezone.America.Los_Angeles=America/Los Angeles
+pref.timezone.America.Maceio=America/Maceio
+pref.timezone.America.Managua=America/Managua
+pref.timezone.America.Manaus=America/Manaus
+pref.timezone.America.Martinique=America/Martinique
+pref.timezone.America.Mazatlan=America/Mazatlan
+pref.timezone.America.Menominee=America/Menominee
+pref.timezone.America.Merida=America/Merida
+pref.timezone.America.Mexico_City=America/Mexico City
+pref.timezone.America.Miquelon=America/Miquelon
+pref.timezone.America.Moncton=America/Moncton
+pref.timezone.America.Monterrey=America/Monterrey
+pref.timezone.America.Montevideo=America/Montevideo
+pref.timezone.America.Montreal=America/Montreal
+pref.timezone.America.Montserrat=America/Montserrat
+pref.timezone.America.Nassau=America/Nassau
+pref.timezone.America.New_York=America/Efrog Newydd
+pref.timezone.America.Nipigon=America/Nipigon
+pref.timezone.America.Nome=America/Nome
+pref.timezone.America.Noronha=America/Noronha
+pref.timezone.America.North_Dakota.Center=America/North Dakota/Center
+pref.timezone.America.North_Dakota.New_Salem=America/North Dakota/New Salem
+pref.timezone.America.Panama=America/Panama
+pref.timezone.America.Pangnirtung=America/Pangnirtung
+pref.timezone.America.Paramaribo=America/Paramaribo
+pref.timezone.America.Phoenix=America/Phoenix
+pref.timezone.America.Port-au-Prince=America/Port-au-Prince
+pref.timezone.America.Port_of_Spain=America/Port of Spain
+pref.timezone.America.Porto_Velho=America/Porto Velho
+pref.timezone.America.Puerto_Rico=America/Puerto Rico
+pref.timezone.America.Rainy_River=America/Rainy River
+pref.timezone.America.Rankin_Inlet=America/Rankin Inlet
+pref.timezone.America.Recife=America/Recife
+pref.timezone.America.Regina=America/Regina
+pref.timezone.America.Rio_Branco=America/Rio Branco
+pref.timezone.America.Santiago=America/Santiago
+pref.timezone.America.Santo_Domingo=America/Santo Domingo
+pref.timezone.America.Sao_Paulo=America/Sao Paulo
+pref.timezone.America.Scoresbysund=America/Scoresbysund
+pref.timezone.America.Shiprock=America/Shiprock
+pref.timezone.America.St_Johns=America/St. Johns
+pref.timezone.America.St_Kitts=America/St. Kitts
+pref.timezone.America.St_Lucia=America/St. Lucia
+pref.timezone.America.St_Thomas=America/St. Thomas
+pref.timezone.America.St_Vincent=America/St. Vincent
+pref.timezone.America.Swift_Current=America/Swift Current
+pref.timezone.America.Tegucigalpa=America/Tegucigalpa
+pref.timezone.America.Thule=America/Thule
+pref.timezone.America.Thunder_Bay=America/Thunder Bay
+pref.timezone.America.Tijuana=America/Tijuana
+pref.timezone.America.Toronto=America/Toronto
+pref.timezone.America.Tortola=America/Tortola
+pref.timezone.America.Vancouver=America/Vancouver
+pref.timezone.America.Whitehorse=America/Whitehorse
+pref.timezone.America.Winnipeg=America/Winnipeg
+pref.timezone.America.Yakutat=America/Yakutat
+pref.timezone.America.Yellowknife=America/Yellowknife
+pref.timezone.Antarctica.Casey=Antarctica/Casey
+pref.timezone.Antarctica.Davis=Antarctica/Davis
+pref.timezone.Antarctica.DumontDUrville=Antarctica/DumontDUrville
+pref.timezone.Antarctica.Mawson=Antarctica/Mawson
+pref.timezone.Antarctica.McMurdo=Antarctica/McMurdo
+pref.timezone.Antarctica.Palmer=Antarctica/Palmer
+pref.timezone.Antarctica.Rothera=Antarctica/Rothera
+pref.timezone.Antarctica.South_Pole=Antarctica/Pegwn y De
+pref.timezone.Antarctica.Syowa=Antarctica/Syowa
+pref.timezone.Antarctica.Vostok=Antarctica/Vostok
+pref.timezone.Arctic.Longyearbyen=Arctig/Longyearbyen
+pref.timezone.Asia.Aden=Asia/Aden
+pref.timezone.Asia.Almaty=Asia/Almaty
+pref.timezone.Asia.Amman=Asia/Amman
+pref.timezone.Asia.Anadyr=Asia/Anadyr
+pref.timezone.Asia.Aqtau=Asia/Aqtau
+pref.timezone.Asia.Aqtobe=Asia/Aqtobe
+pref.timezone.Asia.Ashgabat=Asia/Ashgabat
+pref.timezone.Asia.Baghdad=Asia/Baghdad
+pref.timezone.Asia.Bahrain=Asia/Bahrain
+pref.timezone.Asia.Baku=Asia/Baku
+pref.timezone.Asia.Bangkok=Asia/Bangkok
+pref.timezone.Asia.Beirut=Asia/Beirut
+pref.timezone.Asia.Bishkek=Asia/Bishkek
+pref.timezone.Asia.Brunei=Asia/Brunei
+pref.timezone.Asia.Choibalsan=Asia/Choibalsan
+pref.timezone.Asia.Chongqing=Asia/Chongqing
+pref.timezone.Asia.Colombo=Asia/Colombo
+pref.timezone.Asia.Damascus=Asia/Damascus
+pref.timezone.Asia.Dhaka=Asia/Dhaka
+pref.timezone.Asia.Dili=Asia/Dili
+pref.timezone.Asia.Dubai=Asia/Dubai
+pref.timezone.Asia.Dushanbe=Asia/Dushanbe
+pref.timezone.Asia.Gaza=Asia/Gaza
+pref.timezone.Asia.Harbin=Asia/Harbin
+pref.timezone.Asia.Hong_Kong=Asia/Hong Kong
+pref.timezone.Asia.Hovd=Asia/Hovd
+pref.timezone.Asia.Irkutsk=Asia/Irkutsk
+pref.timezone.Asia.Istanbul=Asia/Istanbul
+pref.timezone.Asia.Jakarta=Asia/Jakarta
+pref.timezone.Asia.Jayapura=Asia/Jayapura
+pref.timezone.Asia.Jerusalem=Asia/Jerusalem
+pref.timezone.Asia.Kabul=Asia/Kabul
+pref.timezone.Asia.Kamchatka=Asia/Kamchatka
+pref.timezone.Asia.Karachi=Asia/Karachi
+pref.timezone.Asia.Kashgar=Asia/Kashgar
+pref.timezone.Asia.Kathmandu=Asia/Kathmandu
+pref.timezone.Asia.Krasnoyarsk=Asia/Krasnoyarsk
+pref.timezone.Asia.Kuala_Lumpur=Asia/Kuala Lumpur
+pref.timezone.Asia.Kuching=Asia/Kuching
+pref.timezone.Asia.Kuwait=Asia/Kuwait
+pref.timezone.Asia.Macau=Asia/Macau
+pref.timezone.Asia.Magadan=Asia/Magadan
+pref.timezone.Asia.Makassar=Asia/Makassar
+pref.timezone.Asia.Manila=Asia/Manila
+pref.timezone.Asia.Muscat=Asia/Muscat
+pref.timezone.Asia.Nicosia=Asia/Nicosia
+pref.timezone.Asia.Novosibirsk=Asia/Novosibirsk
+pref.timezone.Asia.Omsk=Asia/Omsk
+pref.timezone.Asia.Oral=Asia/Oral
+pref.timezone.Asia.Phnom_Penh=Asia/Phnom Penh
+pref.timezone.Asia.Pontianak=Asia/Pontianak
+pref.timezone.Asia.Pyongyang=Asia/Pyongyang
+pref.timezone.Asia.Qatar=Asia/Qatar
+pref.timezone.Asia.Qyzylorda=Asia/Qyzylorda
+pref.timezone.Asia.Rangoon=Asia/Rangoon
+pref.timezone.Asia.Riyadh=Asia/Riyadh
+pref.timezone.Asia.Sakhalin=Asia/Sakhalin
+pref.timezone.Asia.Samarkand=Asia/Samarkand
+pref.timezone.Asia.Seoul=Asia/Seoul
+pref.timezone.Asia.Shanghai=Asia/Shanghai
+pref.timezone.Asia.Singapore=Asia/Singapore
+pref.timezone.Asia.Taipei=Asia/Taipei
+pref.timezone.Asia.Tashkent=Asia/Tashkent
+pref.timezone.Asia.Tbilisi=Asia/Tbilisi
+pref.timezone.Asia.Tehran=Asia/Tehran
+pref.timezone.Asia.Thimphu=Asia/Thimphu
+pref.timezone.Asia.Tokyo=Asia/Tokyo
+pref.timezone.Asia.Ulaanbaatar=Asia/Ulaanbaatar
+pref.timezone.Asia.Urumqi=Asia/Urumqi
+pref.timezone.Asia.Vientiane=Asia/Vientiane
+pref.timezone.Asia.Vladivostok=Asia/Vladivostok
+pref.timezone.Asia.Yakutsk=Asia/Yakutsk
+pref.timezone.Asia.Yekaterinburg=Asia/Yekaterinburg
+pref.timezone.Asia.Yerevan=Asia/Yerevan
+pref.timezone.Atlantic.Azores=Môr Iwerydd/Azores
+pref.timezone.Atlantic.Bermuda=Môr Iwerydd/Bermuda
+pref.timezone.Atlantic.Canary=Môr Iwerydd/Canary
+pref.timezone.Atlantic.Cape_Verde=Môr Iwerydd/Cape Verde
+pref.timezone.Atlantic.Faroe=Môr Iwerydd/Faroe
+pref.timezone.Atlantic.Madeira=Môr Iwerydd/Madeira
+pref.timezone.Atlantic.Reykjavik=Môr Iwerydd/Reykjavik
+pref.timezone.Atlantic.South_Georgia=Môr Iwerydd/South Georgia
+pref.timezone.Atlantic.St_Helena=Môr Iwerydd/St. Helena
+pref.timezone.Atlantic.Stanley=Môr Iwerydd/Stanley
+pref.timezone.Australia.Adelaide=Awstralia/Adelaide
+pref.timezone.Australia.Brisbane=Awstralia/Brisbane
+pref.timezone.Australia.Broken_Hill=Awstralia/Broken Hill
+pref.timezone.Australia.Currie=Awstralia/Currie
+pref.timezone.Australia.Darwin=Awstralia/Darwin
+pref.timezone.Australia.Eucla=Awstralia/Eucla
+pref.timezone.Australia.Hobart=Awstralia/Hobart
+pref.timezone.Australia.Lindeman=Awstralia/Lindeman
+pref.timezone.Australia.Lord_Howe=Awstralia/Lord Howe
+pref.timezone.Australia.Melbourne=Awstralia/Melbourne
+pref.timezone.Australia.Perth=Awstralia/Perth
+pref.timezone.Australia.Sydney=Australia/Sydney
+pref.timezone.Europe.Amsterdam=Ewrop/Amsterdam
+pref.timezone.Europe.Andorra=Ewrop/Andorra
+pref.timezone.Europe.Athens=Ewrop/Athens
+pref.timezone.Europe.Belgrade=Europe/Belgrade
+pref.timezone.Europe.Berlin=Ewrop/Berlin
+pref.timezone.Europe.Bratislava=Europe/Bratislava
+pref.timezone.Europe.Brussels=Europe/Brwsel
+pref.timezone.Europe.Bucharest=Ewrop/Bucharest
+pref.timezone.Europe.Budapest=Ewrop/Budapest
+pref.timezone.Europe.Chisinau=Ewrop/Chisinau
+pref.timezone.Europe.Copenhagen=Ewrop/Copenhagen
+pref.timezone.Europe.Dublin=Europe/Dulun
+pref.timezone.Europe.Gibraltar=Europe/Gibraltar
+pref.timezone.Europe.Guernsey=Ewrop/Guernsey
+pref.timezone.Europe.Helsinki=Ewrop/Helsinki
+pref.timezone.Europe.Isle_of_Man=Ewrop/Ynys Manaw
+pref.timezone.Europe.Istanbul=Ewrop/Istanbul
+pref.timezone.Europe.Jersey=Ewrop/Jersey
+pref.timezone.Europe.Kaliningrad=Ewrop/Kalingrad
+pref.timezone.Europe.Kiev=Ewrop/Kiev
+pref.timezone.Europe.Lisbon=Ewrop/Lisbon
+pref.timezone.Europe.Ljubljana=Ewrop/Ljubljana
+pref.timezone.Europe.London=Ewrop/Llundain
+pref.timezone.Europe.Luxembourg=Ewrop/Lwcsembwrg
+pref.timezone.Europe.Madrid=Ewrop/Madrid
+pref.timezone.Europe.Malta=Ewrop/Malta
+pref.timezone.Europe.Mariehamn=Ewrop/Mariehamn
+pref.timezone.Europe.Minsk=Ewrop/Minsk
+pref.timezone.Europe.Monaco=Ewrop/Monaco
+pref.timezone.Europe.Moscow=Ewrop/Moscow
+pref.timezone.Europe.Nicosia=Ewrop/Nicosia
+pref.timezone.Europe.Oslo=Ewrop/Oslo
+pref.timezone.Europe.Paris=Ewrop/Paris
+pref.timezone.Europe.Podgorica=Ewrop/Podgorica
+pref.timezone.Europe.Prague=Ewrop/Prâg
+pref.timezone.Europe.Riga=Ewrop/Riga
+pref.timezone.Europe.Rome=Ewrop/Rhufain
+pref.timezone.Europe.Samara=Ewrop/Samara
+pref.timezone.Europe.San_Marino=Ewrop/San Marino
+pref.timezone.Europe.Sarajevo=Ewrop/Sarajevo
+pref.timezone.Europe.Simferopol=Ewrop/Simferopol
+pref.timezone.Europe.Skopje=Ewrop/Skopje
+pref.timezone.Europe.Sofia=Ewrop/Sofia
+pref.timezone.Europe.Stockholm=Ewrop/Stockholm
+pref.timezone.Europe.Tallinn=Ewrop/Tallinn
+pref.timezone.Europe.Tirane=Ewrop/Tirane
+pref.timezone.Europe.Uzhgorod=Ewrop/Uzhgorod
+pref.timezone.Europe.Vaduz=Ewrop/Vaduz
+pref.timezone.Europe.Vatican=Ewrop/Fatican
+pref.timezone.Europe.Vienna=Ewrop/Vienna
+pref.timezone.Europe.Vilnius=Ewrop/Vilnius
+pref.timezone.Europe.Volgograd=Ewrop/Volgograd
+pref.timezone.Europe.Warsaw=Ewrop/Warsaw
+pref.timezone.Europe.Zagreb=Ewrop/Zagreb
+pref.timezone.Europe.Zaporozhye=Ewrop/Zaporozhye
+pref.timezone.Europe.Zurich=Ewrop/Zurich
+pref.timezone.Indian.Antananarivo=Môr India/Antananarivo
+pref.timezone.Indian.Chagos=Môr India/Chagos
+pref.timezone.Indian.Christmas=Môr India/Christmas
+pref.timezone.Indian.Cocos=Môr India/Cocos
+pref.timezone.Indian.Comoro=Môr India/Comoro
+pref.timezone.Indian.Kerguelen=Môr India/Kerguelen
+pref.timezone.Indian.Mahe=Môr India/Mahe
+pref.timezone.Indian.Maldives=Môr India/Maldives
+pref.timezone.Indian.Mauritius=Môr India/Mauritius
+pref.timezone.Indian.Mayotte=Môr India/Mayotte
+pref.timezone.Indian.Reunion=Môr India/Reunion
+pref.timezone.Pacific.Apia=Môr Tawel/Apia
+pref.timezone.Pacific.Auckland=Môr Tawel/Auckland
+pref.timezone.Pacific.Chatham=Môr Tawel/Cnatham
+pref.timezone.Pacific.Easter=Môr Tawel/Easter
+pref.timezone.Pacific.Efate=Môr Tawel/Efate
+pref.timezone.Pacific.Enderbury=Môr Tawel/Enderbury
+pref.timezone.Pacific.Fakaofo=Môr Tawel/Fakaofo
+pref.timezone.Pacific.Fiji=Môr Tawel/Fiji
+pref.timezone.Pacific.Funafuti=Môr Tawel/Funafuti
+pref.timezone.Pacific.Galapagos=Môr Tawel/Galapagos
+pref.timezone.Pacific.Gambier=Môr Tawel/Gambier
+pref.timezone.Pacific.Guadalcanal=Môr Tawel/Guadalcanal
+pref.timezone.Pacific.Guam=Môr Tawel/Guam
+pref.timezone.Pacific.Honolulu=Môr Tawel/Honolulu
+pref.timezone.Pacific.Johnston=Môr Tawel/Johnston
+pref.timezone.Pacific.Kiritimati=Môr Tawel/Kiritimati
+pref.timezone.Pacific.Kosrae=Môr Tawel/Kosrae
+pref.timezone.Pacific.Kwajalein=Môr Tawel/Kwajalein
+pref.timezone.Pacific.Majuro=Môr Tawel/Majuro
+pref.timezone.Pacific.Marquesas=Môr Tawel/Marquesas
+pref.timezone.Pacific.Midway=Môr Tawel/Midway
+pref.timezone.Pacific.Nauru=Môr Tawel/Nauru
+pref.timezone.Pacific.Niue=Môr Tawel/Niue
+pref.timezone.Pacific.Norfolk=Môr Tawel/Norfolk
+pref.timezone.Pacific.Noumea=Môr Tawel/Noumea
+pref.timezone.Pacific.Pago_Pago=Môr Tawel/Pago Pago
+pref.timezone.Pacific.Palau=Môr Tawel/Palau
+pref.timezone.Pacific.Pitcairn=Môr Tawel/Pitcairn
+pref.timezone.Pacific.Ponape=Môr Tawel/Ponape
+pref.timezone.Pacific.Port_Moresby=Môr Tawel/Port Moresby
+pref.timezone.Pacific.Rarotonga=Môr Tawel/Rarotonga
+pref.timezone.Pacific.Saipan=Môr Tawel/Saipan
+pref.timezone.Pacific.Tahiti=Môr Tawel/Tahiti
+pref.timezone.Pacific.Tarawa=Môr Tawel/Tarawa
+pref.timezone.Pacific.Tongatapu=Môr Tawel/Tongatapu
+pref.timezone.Pacific.Truk=Môr Tawel/Truk
+pref.timezone.Pacific.Wake=Môr Tawel/Wake
+pref.timezone.Pacific.Wallis=Môr Tawel/Wallis
+
+# the following have been missing
+pref.timezone.America.Indiana.Tell_City=America/Indiana/Tell City
+pref.timezone.America.Indiana.Winamac=America/Indiana/Winamac
+pref.timezone.America.Marigot=America/Marigot
+pref.timezone.America.Resolute=America/Resolute
+pref.timezone.America.St_Barthelemy=America/St. Barthelemy
+
+# added with 2008d:
+pref.timezone.America.Argentina.San_Luis=America/Yr Ariannin/San Luis
+pref.timezone.America.Santarem=America/Santarem
+pref.timezone.Asia.Ho_Chi_Minh=Asia/Ho Chi Minh
+pref.timezone.Asia.Kolkata=Asia/Kolkata
+
+# added with 2008i:
+pref.timezone.America.Argentina.Salta=America/Yr Ariannin/Salta
+
+# added with 2010i
+pref.timezone.America.Matamoros=America/Matamoros
+pref.timezone.America.Ojinaga=America/Ojinaga
+pref.timezone.America.Santa_Isabel=America/Santa Isabel
+pref.timezone.Antarctica.Macquarie=Antarctica/Macquarie
+pref.timezone.Asia.Novokuznetsk=Asia/Novokuznetsk
+
+#added with 2011b
+pref.timezone.America.Bahia_Banderas=America/Bahia Banderas
+pref.timezone.America.North_Dakota.Beulah=America/North Dakota/Beulah
+pref.timezone.Pacific.Chuuk=Môr Tawel/Chuuk
+pref.timezone.Pacific.Pohnpei=Môr Tawel/Pohnpei
+
+#added with 2011n
+pref.timezone.Africa.Juba=Affrica/Juba
+pref.timezone.America.Kralendijk=America/Kralendijk
+pref.timezone.America.Lower_Princes=America/Lower Princes
+pref.timezone.America.Metlakatla=America/Metlakatla
+pref.timezone.America.Sitka=America/Sitka
+pref.timezone.Asia.Hebron=Asia/Hebron
+
+#added with 2013a
+pref.timezone.America.Creston=America/Creston
+pref.timezone.Asia.Khandyga=Asia/Khandyga
+pref.timezone.Asia.Ust-Nera=Asia/Ust-Nera
+pref.timezone.Europe.Busingen=Ewrop/Busingen
+
+#added with 2014b
+pref.timezone.Antarctica.Troll=Antarctica/Troll
+
+#added with 2014j
+pref.timezone.Asia.Chita=Asia/Chita
+pref.timezone.Asia.Srednekolymsk=Asia/Srednekolymsk
+pref.timezone.Pacific.Bougainville=Y Môr Tawel/Bougainville
+
+#added with 2.2015g
+pref.timezone.America.Fort_Nelson=America/Fort Nelson
+
+#added with 2.2016b
+pref.timezone.Europe.Ulyanovsk=Ewrop/Ulyanovsk
+pref.timezone.Europe.Astrakhan=Ewrop/Astrakhan
+pref.timezone.Asia.Barnaul=Asia/Barnaul
+
+#added with 2.2016i
+pref.timezone.Asia.Yangon=Asia/Yangon
+pref.timezone.Asia.Tomsk=Asia/Tomsk
+pref.timezone.Asia.Famagusta=Asia/Famagusta
+pref.timezone.Europe.Kirov=Ewrop/Kirov
+
+#added with 2.2016j
+pref.timezone.Europe.Saratov=Ewrop/Saratov
+pref.timezone.Asia.Atyrau=Asia/Atyrau
+
+#added with 2.2017b
+pref.timezone.America.Punta_Arenas=America/Punta Arenas
+
+#added with 2.2018i
+pref.timezone.Asia.Qostanay=Asia/Qostanay
+
+#added with 2.2020a
+pref.timezone.America.Nuuk=America/Nuuk
diff --git a/l10n-cy/calendar/chrome/lightning/lightning-toolbar.dtd b/l10n-cy/calendar/chrome/lightning/lightning-toolbar.dtd
new file mode 100644
index 0000000000..89f6f38fe8
--- /dev/null
+++ b/l10n-cy/calendar/chrome/lightning/lightning-toolbar.dtd
@@ -0,0 +1,51 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY lightning.toolbar.calendar.name "Bar Offer Calendr">
+<!ENTITY lightning.toolbar.calendar.name.accesskey "B">
+<!ENTITY lightning.toolbar.task.name "Bar Offer Tasgau">
+<!ENTITY lightning.toolbar.task.name.accesskey "T">
+
+<!ENTITY lightning.toolbar.sync.label "Cydweddu">
+<!ENTITY lightning.toolbar.sync.tooltip "Ail-lwytho calendrau a chydweddu newidiadau">
+<!ENTITY lightning.toolbar.delete.label "Dileu">
+<!ENTITY lightning.toolbar.delete.tooltip "Dileu digwyddiadau neu dasgau penodol">
+<!ENTITY lightning.toolbar.edit.label "Golygu">
+<!ENTITY lightning.toolbar.edit.tooltip "Golygu digwyddiadau neu dasgau penodol">
+<!ENTITY lightning.toolbar.gototoday.label "Mynd i Heddiw">
+<!ENTITY lightning.toolbar.gototoday.tooltip "Mynd i Heddiw">
+<!ENTITY lightning.toolbar.print.label "Argraffu">
+<!ENTITY lightning.toolbar.print.tooltip "Argraffu digwyddiadau neu dasgau">
+
+<!-- Mode Toolbar -->
+<!ENTITY lightning.toolbar.calendar.label     "Calendr">
+<!ENTITY lightning.toolbar.calendar.tooltip   "Symud i'r tab calendr">
+<!ENTITY lightning.toolbar.calendar.accesskey "C">
+<!ENTITY lightning.toolbar.task.label         "Tasgau">
+<!ENTITY lightning.toolbar.task.tooltip       "Symud i'r tab tasgau">
+<!ENTITY lightning.toolbar.task.accesskey     "T">
+
+<!-- Toolbar write button -->
+<!ENTITY lightning.toolbar.newevent.label     "Digwyddiad">
+<!ENTITY lightning.toolbar.newevent.tooltip   "Creu digwyddiad newydd">
+<!ENTITY lightning.toolbar.newtask.label      "Tasg">
+<!ENTITY lightning.toolbar.newtask.tooltip    "Creu tasg newydd">
+
+<!-- Calendar and Task Mode Toolbar -->
+<!ENTITY lightning.toolbar.day.label                 "Diwrnod">
+<!ENTITY lightning.toolbar.day.accesskey             "D">
+<!ENTITY lightning.toolbar.week.label                "Wythnos">
+<!ENTITY lightning.toolbar.week.accesskey            "W">
+<!ENTITY lightning.toolbar.multiweek.label           "Wythnosau">
+<!ENTITY lightning.toolbar.multiweek.accesskey       "y">
+<!ENTITY lightning.toolbar.month.label               "Mis">
+<!ENTITY lightning.toolbar.month.accesskey           "M">
+<!-- LOCALIZATION NOTE: the same as appmenuButton.label and appmenuButton1.tooltip
+     from messenger.dtd -->
+<!ENTITY lightning.toolbar.appmenuButton.label       "AppMenu">
+<!ENTITY lightning.toolbar.appmenuButton1.tooltip    "Dangos dewislen &brandShortName;">
+<!ENTITY lightning.toolbar.calendarmenu.label        "Paen Calendr">
+<!ENTITY lightning.toolbar.calendarmenu.accesskey    "P">
+<!ENTITY lightning.toolbar.calendarpane.label        "Dangos Paen Calendr">
+<!ENTITY lightning.toolbar.calendarpane.accesskey    "P">
diff --git a/l10n-cy/calendar/chrome/lightning/lightning.dtd b/l10n-cy/calendar/chrome/lightning/lightning.dtd
new file mode 100644
index 0000000000..61bea192f4
--- /dev/null
+++ b/l10n-cy/calendar/chrome/lightning/lightning.dtd
@@ -0,0 +1,116 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- WARNING! This file contains UTF-8 encoded characters!
+   - If this ==> … <== doesn't look like an ellipsis (three dots in a row),
+   - your editor isn't using UTF-8 encoding and may munge up the document!
+  -->
+
+<!-- Tools menu -->
+<!ENTITY lightning.preferencesLabel "Calendr">
+
+<!-- New menu popup in File menu -->
+<!ENTITY lightning.menupopup.new.event.label    "Digwyddiad…">
+<!ENTITY lightning.menupopup.new.event.accesskey "D">
+<!ENTITY lightning.menupopup.new.task.label     "Tasg…">
+<!ENTITY lightning.menupopup.new.task.accesskey "T">
+<!ENTITY lightning.menupopup.new.calendar.label "Calendr…">
+<!ENTITY lightning.menupopup.new.calendar.accesskey "C">
+
+<!-- Open menu popup in File menu -->
+<!ENTITY lightning.menupopup.open.label               "Agor">
+<!ENTITY lightning.menupopup.open.accesskey           "A">
+<!ENTITY lightning.menupopup.open.message.label       "Neges wedi'i Chadw…">
+<!ENTITY lightning.menupopup.open.message.accesskey   "N">
+
+<!-- Open menu popup in File menu -->
+<!ENTITY lightning.menupopup.open.calendar.label      "Ffeil Calendr…">
+<!ENTITY lightning.menupopup.open.calendar.accesskey  "F">
+
+<!-- View Menu -->
+<!ENTITY lightning.menu.view.calendar.label            "Calendr">
+<!ENTITY lightning.menu.view.calendar.accesskey        "a">
+<!ENTITY lightning.menu.view.tasks.label               "Tasgau">
+<!ENTITY lightning.menu.view.tasks.accesskey           "a">
+
+<!-- Events and Tasks menu -->
+<!ENTITY lightning.menu.eventtask.label                "Digwyddiadau a Thasgau">
+<!ENTITY lightning.menu.eventtask.accesskey            "D">
+
+<!-- properties dialog, calendar creation wizard -->
+<!-- LOCALIZATON NOTE(lightning.calendarproperties.email.label,
+     lightning.calendarproperties.forceEmailScheduling.label)
+     These strings are used in the calendar wizard and the calendar properties dialog, but are only
+     displayed when setting/using a caldav calendar -->
+<!ENTITY lightning.calendarproperties.email.label                           "E-bost:">
+<!ENTITY lightning.calendarproperties.forceEmailScheduling.label            "Ffafrio amserlennu e-bost ochr y cleient">
+<!-- LOCALIZATON NOTE(lightning.calendarproperties.forceEmailScheduling.tooltiptext1,
+     lightning.calendarproperties.forceEmailScheduling.tooltiptext2)
+     - tooltiptext1 is used in the calendar wizard when setting a new caldav calendar
+     - tooltiptext2 is used in the calendar properties dialog for caldav calendars -->
+<!ENTITY lightning.calendarproperties.forceEmailScheduling.tooltiptext1     "Ar hyn o bryd, mae modd galluogi hwn ar ôl gosod y calendr hwn yn ei ddeialog priodwedd os yw gweinydd y calendr yn cymryd gofal o amserlennu.">
+<!ENTITY lightning.calendarproperties.forceEmailScheduling.tooltiptext2     "Dim ond os yw gweinydd yr amserlenni ar gael mae'r dewis hwn ar gael. Bydd ei alluogi yn caniatau mynd yn ol i'r amserlemnni e-bost safonol yn lle ei adael ar y gweinydd.">
+
+<!-- iMIP Bar (meeting support) -->
+<!ENTITY lightning.imipbar.btnAccept.label                                  "Derbyn">
+<!ENTITY lightning.imipbar.btnAccept2.tooltiptext                           "Derbyn gwahoddiad i'r digwyddiad">
+<!ENTITY lightning.imipbar.btnAcceptRecurrences.label                       "Derbyn y cyfan">
+<!ENTITY lightning.imipbar.btnAcceptRecurrences2.tooltiptext                "Derbyn gwahoddiad digwyddiad ar gyfer pob achlysur o'r digwyddiad">
+<!ENTITY lightning.imipbar.btnAdd.label                                     "Ychwanegu">
+<!ENTITY lightning.imipbar.btnAdd.tooltiptext                               "Ychwanegu'r digwyddiad i'r calendr">
+<!ENTITY lightning.imipbar.btnDecline.label                                 "Gwrthod">
+<!ENTITY lightning.imipbar.btnDecline2.tooltiptext                          "Gwrthod gwahoddiad i'r digwyddiad">
+<!ENTITY lightning.imipbar.btnDeclineRecurrences.label                      "Gwrthod pob un">
+<!ENTITY lightning.imipbar.btnDeclineRecurrences2.tooltiptext               "Gwrthod gwahoddiad i ddigwyddiad ar gyfer pob achlysur o'r digwyddiad">
+<!ENTITY lightning.imipbar.btnDeclineCounter.label                          "Gwrthod">
+<!ENTITY lightning.imipbar.btnDeclineCounter.tooltiptext                    "Gwrthod y gwrth gynnig">
+<!ENTITY lightning.imipbar.btnDelete.label                                  "Dileu">
+<!ENTITY lightning.imipbar.btnDelete.tooltiptext                            "Dileu o'r calendr">
+<!ENTITY lightning.imipbar.btnDetails.label                                 "Manylion…">
+<!ENTITY lightning.imipbar.btnDetails.tooltiptext                           "Dangos manylion y digwyddiad">
+<!ENTITY lightning.imipbar.btnDoNotShowImipBar.label                        "Peidio â dangos y negeseuon hyn i mi">
+<!ENTITY lightning.imipbar.btnGoToCalendar.label                            "Calendr">
+<!ENTITY lightning.imipbar.btnGoToCalendar.tooltiptext                      "Mynd i'r tab calendr">
+<!ENTITY lightning.imipbar.btnMore.label                                    "Rhagor">
+<!ENTITY lightning.imipbar.btnMore.tooltiptext                              "Cliciwch i ddangos rhagor o ddewisiadau">
+<!ENTITY lightning.imipbar.btnReconfirm2.label                              "Ail gadarnhau">
+<!ENTITY lightning.imipbar.btnReconfirm.tooltiptext                         "Anfon ail gadarnhad i'r trefnydd">
+<!ENTITY lightning.imipbar.btnReschedule.label                              "Aildrefnu">
+<!ENTITY lightning.imipbar.btnReschedule.tooltiptext                        "Aildrefnu'r digwyddiad">
+<!ENTITY lightning.imipbar.btnSaveCopy.label                                "Cadw copi">
+<!ENTITY lightning.imipbar.btnSaveCopy.tooltiptext                          "Cadw copi o'r digwyddiad i'r calendr yn annibynnol o ateb i'r trefnydd. Bydd y rhestr o fynychwyr yn cael ei glirio.">
+<!ENTITY lightning.imipbar.btnTentative.label                               "Amodol">
+<!ENTITY lightning.imipbar.btnTentative2.tooltiptext                        "Derbyn gwahoddiad i ddigwyddiad yn amodol">
+<!ENTITY lightning.imipbar.btnTentativeRecurrences.label                    "Amodol i'r cyfan">
+<!ENTITY lightning.imipbar.btnTentativeRecurrences2.tooltiptext             "Derbyn gwahoddiad i ddigwyddiad yn amodol ar gyfer pob achlysur o'r digwyddiad">
+<!ENTITY lightning.imipbar.btnUpdate.label                                  "Diweddaru">
+<!ENTITY lightning.imipbar.btnUpdate.tooltiptext                            "Diweddaru'r digwyddiad yn y calendr">
+<!ENTITY lightning.imipbar.description                                      "Mae'r neges hon yn cynnwys gwahoddiad i ddigwyddiad.">
+
+<!ENTITY lightning.imipbar.btnSend.label                                    "Anfon ymateb nawr">
+<!ENTITY lightning.imipbar.btnSend.tooltiptext                              "Anfon ymateb i'r trefnydd">
+<!ENTITY lightning.imipbar.btnSendSeries.tooltiptext                        "Anfon ymateb am y gyfres gyfan i'r trefnydd">
+<!ENTITY lightning.imipbar.btnDontSend.label                                "Peidio anfon ymateb">
+<!ENTITY lightning.imipbar.btnDontSend.tooltiptext                          "Newid eich statws cyfranogi heb anfon ymateb i'r trefnydd">
+<!ENTITY lightning.imipbar.btnDontSendSeries.tooltiptext                    "Newid eich statws cyfranogi ar gyfer y gyfres heb anfon ymateb i'r trefnydd">
+
+<!-- Lightning specific keybindings -->
+<!ENTITY lightning.keys.event.showCalendar.key "C">
+<!ENTITY lightning.keys.event.showTasks.key "D">
+<!ENTITY lightning.keys.event.new "I">
+<!ENTITY lightning.keys.todo.new "D">
+
+<!-- Account Central page -->
+<!ENTITY lightning.acctCentral.newCalendar.label "Creu calendr newydd">
+
+<!-- today-pane-specific -->
+<!ENTITY todaypane.showMinimonth.label "Dangos Mis Bach">
+<!ENTITY todaypane.showMinimonth.accesskey "M">
+<!ENTITY todaypane.showMiniday.label "Dangos Diwrnod Bach">
+<!ENTITY todaypane.showMiniday.accesskey  "D">
+<!ENTITY todaypane.showNone.label "Dangos Dim">
+<!ENTITY todaypane.showNone.accesskey "a">
+<!ENTITY todaypane.showTodayPane.label "Dangos Paen Heddiw">
+<!ENTITY todaypane.showTodayPane.accesskey "P">
+<!ENTITY todaypane.statusButton.label "Paen Heddiw">
diff --git a/l10n-cy/calendar/chrome/lightning/lightning.properties b/l10n-cy/calendar/chrome/lightning/lightning.properties
new file mode 100644
index 0000000000..15a2b8773e
--- /dev/null
+++ b/l10n-cy/calendar/chrome/lightning/lightning.properties
@@ -0,0 +1,165 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Task mode title
+taskModeApplicationTitle=Tasgau
+
+# Tab titles
+tabTitleCalendar=Calendr
+tabTitleTasks=Tasgau
+
+# Html event display in message
+imipHtml.header=Gwahoddiad i Ddigwyddiad
+imipHtml.summary=Teitl:
+imipHtml.location=Lleoliad:
+imipHtml.when=Pryd:
+imipHtml.organizer=Trefnydd:
+imipHtml.description=Disgrifiad:
+# LOCALIZATION_NOTE(imipHtml.attachments): This is a label for one or more (additional) links to
+# documents or websites attached to this event.
+imipHtml.attachments=Atodiadau:
+imipHtml.comment=Sylwadau:
+imipHtml.attendees=Mynychwyr:
+# LOCALIZATION_NOTE(imipHtml.url): This is a label for a reference to an (alternate) online
+# representation of the event (either directly human readable or not).
+imipHtml.url=Dolen Perthnasol:
+imipHtml.canceledOccurrences=Diddymu Achlysuron:
+imipHtml.modifiedOccurrences=Achlysur Newidiwyd:
+imipHtml.newLocation=Lleoliad Newydd: %1$S
+# LOCALIZATION_NOTE(imipHtml.attendeeDelegatedFrom): this is appended behind an attendee name in the
+# email invitation preview - don't add leading/trailing whitespaces here
+# %1$S - a single delegator or a comma separated list of delegators
+imipHtml.attendeeDelegatedFrom=(trosglwyddwyd o %1$S)
+# LOCALIZATION_NOTE(imipHtml.attendeeDelegatedTo): this is appended behind an attendee name in the
+# email invitation preview - don't add leading/trailing whitespaces here
+# %1$S - a single delegatee or a comma separated list of delegatees
+imipHtml.attendeeDelegatedTo=(trosglwyddwyd i %1$S)
+
+# LOCALIZATION_NOTE(imipHtml.attendee.combined): tooltip for itip icon in email invitation preview.
+# Given an attendee loungeexample.org of type room is a mandatory participant and has accepted the
+# invitation, the tooltip would be:
+# lounge@example.org (room) is a required participant. lounge@example.org has confirmed attendance.
+# %1$S - value of imipHtml.attendeeRole2.*
+# %2$S - value of imipHtml.attendeePartStat2.*
+imipHtml.attendee.combined=%1$S %2$S
+
+# LOCALIZATION_NOTE(imipHtml.attendeeRole2.CHAIR): used to compose
+# imipHtml.attendee.combined
+# %1$S - value of imipHtml.attendeeUserType2.*
+imipHtml.attendeeRole2.CHAIR=Mae %1$S yn cadeirio'r digwyddiad.
+# LOCALIZATION_NOTE(imipHtml.attendeeRole2.NON-PARTICIPANT): used to compose
+# imipHtml.attendee.combined
+# %1$S - value of imipHtml.attendeeUserType2.*
+imipHtml.attendeeRole2.NON-PARTICIPANT=Nid yw %1$S yn cymryd rhan.
+# LOCALIZATION_NOTE(imipHtml.attendeeRole2.OPT-PARTICIPANT): used to compose
+# imipHtml.attendee.combined
+# %1$S - value of imipHtml.attendeeUserType2.*
+imipHtml.attendeeRole2.OPT-PARTICIPANT=Mae'n bosib i %1$S gymryd rhan.
+# LOCALIZATION_NOTE(imipHtml.attendeeRole2.REQ-PARTICIPANT): used to compose
+# imipHtml.attendee.combined
+# %1$S - value of imipHtml.attendeeUserType2.*
+imipHtml.attendeeRole2.REQ-PARTICIPANT=Mae'n angenrheidiol i %1$S gymryd rhan.
+
+# LOCALIZATION_NOTE(imipHtml.attendeePartStat2.ACCEPTED): used to compose
+# imipHtml.attendee.combined
+# %1$S - common name or email address of the attendee
+imipHtml.attendeePartStat2.ACCEPTED=Mae %1$S wedi cadarnhau y bydd yn bresennol.
+# LOCALIZATION_NOTE(imipHtml.attendeePartStat2.DECLINED): used to compose
+# imipHtml.attendee.combined
+# %1$S - common name or email address of the attendee
+imipHtml.attendeePartStat2.DECLINED=Ni fydd %1$S yn bresennol.
+# LOCALIZATION_NOTE(imipHtml.attendeePartStat2.DELEGATED): used to compose
+# imipHtml.attendee.combined
+# %1$S - common name or email address of the attendee
+# %2$S - single delegatee or comma separated list of delegatees
+# delegation is different from invitation forwarding - in case of the former the original attendee
+# is replaced, while on the latter the receiver may take part additionally
+imipHtml.attendeePartStat2.DELEGATED=Mae %1$S wedi dirprwyo presenoldeb i %2$S.
+# LOCALIZATION_NOTE(imipHtml.attendeePartStat2.NEEDS-ACTION): used to compose
+# imipHtml.attendee.combined
+# %1$S - common name or email address of the attendee
+imipHtml.attendeePartStat2.NEEDS-ACTION=Mae %1$S dal angen ateb.
+# LOCALIZATION_NOTE(imipHtml.attendeePartStat2.TENTATIVE): used to compose
+# imipHtml.attendee.combined
+# %1$S - common name or email address of the attendee
+imipHtml.attendeePartStat2.TENTATIVE=Mae %1$S wedi cadarnhau presenoldeb yn amodol.
+
+# LOCALIZATION_NOTE(imipHtml.attendeeUserType2.INDIVIDUAL): used to compose
+# imipHtml.attendeeRole2.*
+# %1$S - email address or common name <email address> representing an individual attendee
+imipHtml.attendeeUserType2.INDIVIDUAL=%1$S
+# LOCALIZATION_NOTE(imipHtml.attendeeUserType2.GROUP): used to compose
+# imipHtml.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a group (e.g. a distribution list)
+imipHtml.attendeeUserType2.GROUP=%1$S (grŵp)
+# LOCALIZATION_NOTE(imipHtml.attendeeUserType2.RESOURCE): used to compose
+# imipHtml.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a resource (e.g. projector)
+imipHtml.attendeeUserType2.RESOURCE=%1$S (adnodd)
+# LOCALIZATION_NOTE(imipHtml.attendeeUserType2.ROOM): used to compose
+# imipHtml.attendeeRole2.*
+# %1$S - email address or common name <email address> representing a room
+imipHtml.attendeeUserType2.ROOM=%1$S (ystafell)
+# LOCALIZATION_NOTE(imipHtml.attendeeUserType2.UNKNOWN): used to compose
+# imipHtml.attendeeRole2.*
+# %1$S - email address or common name <email address> representing an attendee of unknown type
+imipHtml.attendeeUserType2.UNKNOWN=%1$S
+
+imipAddedItemToCal2=Mae'r digwyddiad wedi ei ychwanegu i'ch calendr.
+imipCanceledItem2=Mae'r digwyddiad wedi ei dynnu o'ch calendr.
+imipUpdatedItem2=Digwyddiad wedi'i ddiweddaru.
+imipBarCancelText=Mae'r neges yn cynnwys gwybodaeth am ddiddymu digwyddiad.
+imipBarCounterErrorText=Mae'r neges yn cynnwys gwrth gynnig i wahoddiad nad oes modd ei brosesu.
+imipBarCounterPreviousVersionText=Mae'r neges hon yn cynnwys gwrthgynnig i fersiwn blaenorol o'r gwahoddiad.
+imipBarCounterText=Mae'r neges yn cynnwys gwrthgynnig i wahoddiad.
+imipBarDisallowedCounterText=Mae'r neges hon yn cynnwys gwrthgynnig er i chi analluogi gwrthgynigion i'r digwyddiad hwn.
+imipBarDeclineCounterText=Mae'r neges hon yn cynnwys ateb i'ch gwrthgynnig.
+imipBarRefreshText=Mae'r neges yn gofyn am ddiweddariad am digwyddiad.
+imipBarPublishText=Mae'r neges yn cynnwys gwybodaeth am ddigwyddiad.
+imipBarRequestText=Mae'r neges yn cynnwys gwahoddiad i ddigwyddiad.
+imipBarSentText=Mae'r neges yn cynnwys gwybodaeth am ddigwyddiad.
+imipBarSentButRemovedText=Mae'r neges hon yn cynnwys digwyddiad anfonwyd nad yw yn eich calendr bellach.
+imipBarUpdateText=Mae'r neges yn cynnwys diweddariad i ddigwyddiad cyfredol.
+imipBarUpdateMultipleText=Mae'r neges yn cynnwys diweddariad i ddigwyddiadau cyfredol lluosog.
+imipBarUpdateSeriesText=Mae'r neges yn cynnwys diweddariad i gyfres o ddigwyddiadau cyfredol.
+imipBarAlreadyProcessedText=Mae'r neges yn cynnwys digwyddiad sydd wedi'i brosesu eisoes.
+imipBarProcessedNeedsAction=Mae'r neges yn cynnwys digwyddiad nad ydych wedi ymateb iddi eto.
+imipBarProcessedMultipleNeedsAction=Mae'r neges yn cynnwys cyfres o digwyddiadau nad ydych wedi ymateb iddynt eto.
+imipBarProcessedSeriesNeedsAction=Mae'r neges yn cynnwys cyfres o ddigwyddiad nad ydych wedi ymateb iddynt eto.
+imipBarReplyText=Mae'r neges yn cynnwys ymateb i wahoddiad.
+imipBarReplyToNotExistingItem=Mae'r neges hon yn cynnwys ateb sy'n cyfeirio at ddigwyddiad nad yw yn eich calendr.
+# LOCALIZATION_NOTE(imipBarReplyToRecentlyRemovedItem):
+# %1$S - datetime of deletion
+imipBarReplyToRecentlyRemovedItem=Mae'r neges hon yn cynnwys ateb sy'n cyfeirio at ddigwyddiad dynnwyd oddi ar eich calendr ar %1$S.
+imipBarUnsupportedText2=Mae'r neges yn cynnwys digwyddiad nad yw'r fersiwn yma o %1$S yn gallu ei brosesu.
+imipBarProcessingFailed=Methodd prosesu'r neges. Statws: %1$S.
+imipBarCalendarDeactivated=Mae'r neges hon yn cynnwys gwybodaeth am ddigwyddiadau. Mae angen galluogi  calendr i'w drin.
+imipBarNotWritable=Nid oes calendrau ysgrifenedig wedi'u ffurfweddu ar gyfer gwahoddiadau, gwiriwch briodweddau'r calendr.
+imipSendMail.title=Hysbysiad E-bost
+imipSendMail.text=Hoffech chi anfon yr e-bost hysbysu nawr?
+imipNoIdentity=Dim
+imipNoCalendarAvailable=Nid oes calendrau ysgrifenadwy ar gael.
+
+itipReplySubject2=Ateb Gwahoddiad: %1$S
+itipReplyBodyAccept=Mae %1$S wedi derbyn eich gwahoddiad i ddigwyddiad.
+itipReplyBodyDecline=Mae %1$S wedi gwrthod eich gwahoddiad i ddigwyddiad.
+itipReplySubjectAccept2=Derbyniwyd: %1$S
+itipReplySubjectDecline2=Gwrthodwyd y Gwahoddiad: %1$S
+itipReplySubjectTentative2=Amodol: %1$S
+itipRequestSubject2=Gwahoddiad: %1$S
+itipRequestUpdatedSubject2=Diweddarwyd: %1$S
+itipRequestBody=Mae %1$S wedi eich gwahodd i %2$S
+itipCancelSubject2=Diddymwyd: %1$S
+itipCancelBody=Mae %1$S wedi diddymu'r digwyddiad: %2$S
+itipCounterBody=Mae %1$S wedi gwneud gwrthgynnig ar gyfer "%2$S":
+itipDeclineCounterBody=Mae %1$S wedi gwrthod eich gwrthgynnig ar gyfer "%2$S".
+itipDeclineCounterSubject=Gwrthodwyd y Gwrthgynnig: %1$S
+
+confirmProcessInvitation=Rydych wedi dileu'r eitem yma yn ddiweddar, ydych chi'n siŵr eich bod am brosesu'r gwahoddiad?
+confirmProcessInvitationTitle=Prosesu'r gwahoddiad?
+
+invitationsLink.label=Gwahoddiadau: %1$S
+
+# LOCALIZATION NOTE(noIdentitySelectedNotification):
+noIdentitySelectedNotification=Os hoffech chi ddefnyddio'rcalendr hwn i gadwgwahoddiadau i neu at bobl eraill, dylech ddynodi hunaniaeth e-bost isod.
diff --git a/l10n-cy/calendar/extra-jar.mn b/l10n-cy/calendar/extra-jar.mn
new file mode 100644
index 0000000000..591237101e
--- /dev/null
+++ b/l10n-cy/calendar/extra-jar.mn
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# this is an empty file
+# locales can ship "extra" files from here, to ship a custom set
+# of files for the help system
+# do not put any blank lines in this file
diff --git a/l10n-cy/calendar/lightning-l10n.js b/l10n-cy/calendar/lightning-l10n.js
new file mode 100644
index 0000000000..868504b8f3
--- /dev/null
+++ b/l10n-cy/calendar/lightning-l10n.js
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#filter substitution
+
+# the default day to start the week on
+#0=Sunday 1=Monday 2=Tuesday 3=Wednesday 4=Thursday 5=Friday 6=Saturday
+pref("calendar.week.start", 0);
+
+# default days off (not in work week)
+pref("calendar.week.d0sundaysoff", true);
+pref("calendar.week.d1mondaysoff", false);
+pref("calendar.week.d2tuesdaysoff", false);
+pref("calendar.week.d3wednesdaysoff", false);
+pref("calendar.week.d4thursdaysoff", false);
+pref("calendar.week.d5fridaysoff", false);
+pref("calendar.week.d6saturdaysoff", true);
+
+pref("general.useragent.locale", "@AB_CD@");
+
+# categories
+pref("calendar.categories.names", "Anniversary,Birthday,Business,Calls,Clients,Competition,Customer,Favorites,Follow up,Gifts,Holidays,Ideas,Issues,Meeting,Miscellaneous,Personal,Projects,Public Holiday,Status,Suppliers,Travel,Vacation");
diff --git a/l10n-cy/calendar/sunbird-l10n.js b/l10n-cy/calendar/sunbird-l10n.js
new file mode 100644
index 0000000000..868504b8f3
--- /dev/null
+++ b/l10n-cy/calendar/sunbird-l10n.js
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#filter substitution
+
+# the default day to start the week on
+#0=Sunday 1=Monday 2=Tuesday 3=Wednesday 4=Thursday 5=Friday 6=Saturday
+pref("calendar.week.start", 0);
+
+# default days off (not in work week)
+pref("calendar.week.d0sundaysoff", true);
+pref("calendar.week.d1mondaysoff", false);
+pref("calendar.week.d2tuesdaysoff", false);
+pref("calendar.week.d3wednesdaysoff", false);
+pref("calendar.week.d4thursdaysoff", false);
+pref("calendar.week.d5fridaysoff", false);
+pref("calendar.week.d6saturdaysoff", true);
+
+pref("general.useragent.locale", "@AB_CD@");
+
+# categories
+pref("calendar.categories.names", "Anniversary,Birthday,Business,Calls,Clients,Competition,Customer,Favorites,Follow up,Gifts,Holidays,Ideas,Issues,Meeting,Miscellaneous,Personal,Projects,Public Holiday,Status,Suppliers,Travel,Vacation");
diff --git a/l10n-cy/chat/accounts.dtd b/l10n-cy/chat/accounts.dtd
new file mode 100644
index 0000000000..da806a4978
--- /dev/null
+++ b/l10n-cy/chat/accounts.dtd
@@ -0,0 +1,41 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Account manager window for Instantbird -->
+
+<!ENTITY accounts.title                      "Cyfrifon - &brandShortName;">
+<!ENTITY accountManager.width                "450">
+<!-- Instant messaging account status window for Thunderbird -->
+<!ENTITY accountsWindow.title                "Statws negesu chwim">
+<!ENTITY accountsWindow2.style               "width: 41em; height: 27em;">
+
+<!ENTITY accountManager.newAccount.label     "Cyfrif Newydd">
+<!ENTITY accountManager.newAccount.accesskey "N">
+<!ENTITY accountManager.close.label          "Cau">
+<!ENTITY accountManager.close.accesskey      "u">
+<!-- This should match account.commandkey in instantbird.dtd -->
+<!ENTITY accountManager.close.commandkey     "a">
+<!-- This title must be short, displayed with a big font size -->
+<!ENTITY accountManager.noAccount.title      "Dim cyfrif wedi'i ffurfweddu eto">
+<!ENTITY accountManager.noAccount.description "Cliciwch ar fotwm &accountManager.newAccount.label; i &brandShortName; eich arwain drwy'r broses o'i ffurfweddu.">
+<!ENTITY account.autoSignOn.label     "Mewngofnodi wrth gychwyn">
+<!ENTITY account.autoSignOn.accesskey "M">
+<!ENTITY account.connect.label        "Cysylltu">
+<!ENTITY account.connect.accesskey    "y">
+<!ENTITY account.disconnect.label     "Datgysylltu">
+<!ENTITY account.disconnect.accesskey "D">
+<!ENTITY account.delete.label         "Dileu">
+<!ENTITY account.delete.accesskey     "l">
+<!ENTITY account.edit.label           "Priodweddau">
+<!ENTITY account.edit.accesskey       "P">
+<!ENTITY account.moveup.label         "Symud i fyny">
+<!ENTITY account.movedown.label       "Symud i lawr">
+<!ENTITY account.cancelReconnection.label         "Diddymu ailgysylltu">
+<!ENTITY account.cancelReconnection.accesskey     "D">
+<!ENTITY account.copyDebugLog.label     "Copïo'r Cofnod Dadfygio">
+<!ENTITY account.copyDebugLog.accesskey "C">
+<!ENTITY account.showDebugLog.label     "Dangos y Cofnod Dadfygio">
+<!ENTITY account.showDebugLog.accesskey "D">
+<!ENTITY account.connecting           "Cysylltu…">
+<!ENTITY account.disconnecting        "Dad-gysylltu…">
+<!ENTITY account.disconnected         "Heb Gysylltu">
diff --git a/l10n-cy/chat/accounts.properties b/l10n-cy/chat/accounts.properties
new file mode 100644
index 0000000000..88427bae86
--- /dev/null
+++ b/l10n-cy/chat/accounts.properties
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (passwordPromptTitle, passwordPromptText):
+# %S is replaced with the name of the account
+passwordPromptTitle=Cyfrinair %S
+passwordPromptText=Rhowch eich cyfrinair ar gyfer %S er mwyn cysylltu ag ef.
+passwordPromptSaveCheckbox=Defnyddio'r Rheolwr Cyfrinair i gofio'r cyfrinair.
diff --git a/l10n-cy/chat/commands.properties b/l10n-cy/chat/commands.properties
new file mode 100644
index 0000000000..c02096f8fc
--- /dev/null
+++ b/l10n-cy/chat/commands.properties
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (commands):
+#  %S is a comma separated list of command names.
+commands=Gorchmynion: %S.\nDefnyddiwch /help &lt;command&gt; am rhagor o wybodaeth.
+# LOCALIZATION NOTE (noCommand, noHelp):
+#  %S is the command name the user typed.
+noCommand=Dim gorchymyn '%S'.
+noHelp=Dim neges cymorth ar gyfer y gorchymyn '%S', ymddiheuriadau!
+
+sayHelpString=say &lt;message&gt;: anfon neges heb brosesu gorchmynion.
+rawHelpString=raw &lt;message&gt;: anfon neges heb ryddhau endidau HTML.
+helpHelpString=help &lt;name&gt;: dangos neges cymorth ar gyfer gorchymyn &lt;name&gt; , neu'r rhestr o orchmynion posib pan yn cael eu defnyddio heb baramedr.
+
+# LOCALIZATION NOTE (statusCommand):
+#  %1$S is replaced with a status command name
+#   (one of "back", "away", "busy", "dnd", or "offline").
+#  %2$S is replaced with the localized version of that status type
+#   (one of the 5 strings below).
+statusCommand=%1$S &lt;status message&gt;: gosod y statws i %2$S gyda neges statws dewisol.
+back=ar gael
+away=i ffwrdd
+busy=ddim ar gael
+dnd=ddim ar gael
+offline=all-lein
diff --git a/l10n-cy/chat/contacts.properties b/l10n-cy/chat/contacts.properties
new file mode 100644
index 0000000000..fbe5924459
--- /dev/null
+++ b/l10n-cy/chat/contacts.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (defaultGroup):
+# This is the name of the group that will automatically be created when adding a
+# buddy without specifying a group.
+defaultGroup=Cysylltiadau
diff --git a/l10n-cy/chat/conversations.properties b/l10n-cy/chat/conversations.properties
new file mode 100644
index 0000000000..9535bd3211
--- /dev/null
+++ b/l10n-cy/chat/conversations.properties
@@ -0,0 +1,85 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (targetChanged):
+#  %1$S is the new conversation title (display name of the new target),
+#  %2$S is the protocol name used for the new target.
+targetChanged=Bydd y drafodaeth yn parhau gyda %1$S, gan ddefnyddio %2$S.
+
+# LOCALIZATION NOTE (statusChanged):
+#  %1$S is the display name of the contact.
+#  %2$S is the new status type (a value from status.properties).
+statusChanged=Mae %1$S nawr yn %2$S.
+# LOCALIZATION NOTE (statusChangedWithStatusText):
+#  %1$S is the display name of the contact.
+#  %2$S is the new status type (a value from status.properties).
+#  %3$S is the status text (eg. "I'm currently away from the computer").
+statusChangedWithStatusText=Mae %1$S nawr yn %2$S: %3$S.
+# LOCALIZATION NOTE (statusChangedFromUnknown[WithStatusText]):
+#  special case of the previous 2 strings for when the status was
+#  previously unknown. These 2 strings should not mislead the user
+#  into thinking the person's status has just changed.
+statusChangedFromUnknown=%1$S yw %2$S.
+statusChangedFromUnknownWithStatusText=%1$S yw %2$S: %3$S.
+# LOCALIZATION NOTE (statusKnown[WithStatusText]):
+# special case of the previous 2 strings for when an account has just
+# been reconnected, so the status is now known. These 2 strings should not
+# mislead the user into thinking the person's status has just changed.
+statusKnown=Mae eich cyfrif wedi ei ailgysylltu (%1$S yw %2$S).
+statusKnownWithStatusText=Mae eich cyfrif wedi ei ailgysylltu (%1$S yw %2$S: %3$S).
+# LOCALIZATION NOTE (statusUnknown):
+#  %S is the display name of the contact.
+statusUnknown=Mae eich cyfrif wedi'i ddatgysylltu (nid yw statws %S yn hysbys).
+
+accountDisconnected=Mae eich cyfrif wedi'i ddatgysylltu.
+accountReconnected=Mae eich cyfrif wedi ei ailgysylltu.
+
+# LOCALIZATION NOTE (autoReply):
+#  %S is replaced by the text of a message that was sent as an automatic reply.
+autoReply=Awto-ateb - %S
+
+# LOCALIZATION NOTE (noTopic):
+# Displayed instead of the topic when no topic is set.
+noTopic=Dim pwnc neges o'r ystafell hon.
+
+# LOCALIZATION NOTE (topicSet):
+#  %1$S is the conversation name, %2$S is the topic.
+topicSet=Pwnc %1$S yw: %2$S.
+# LOCALIZATION NOTE (topicNotSet):
+#  %S is the conversation name.
+topicNotSet=Nid oes pwnc ar gyfer %S.
+# LOCALIZATION NOTE (topicChanged):
+#  %1$S is the user who changed the topic, %2$S is the new topic.
+topicChanged=Mae %1$S wedi newid y pwnc i: %2$S.
+# LOCALIZATION NOTE (topicCleared):
+#  %1$S is the user who cleared the topic.
+topicCleared=Mae %1$S wedi clirio'r pwnc.
+
+# LOCALIZATION NOTE (nickSet):
+#   This is displayed as a system message when a participant changes his/her
+#   nickname in a conversation.
+#   %1$S is the old nick.
+#   %2$S is the new nick.
+nickSet=Mae %1$S nawr yn cael ei adnabod fel %2$S.
+# LOCALIZATION NOTE (nickSet.you):
+#   This is displayed as a system message when your nickname is changed.
+#   %S is your new nick.
+nickSet.you=Rydych nawr yn cael eich adnabod fel %S.
+
+# LOCALIZATION NOTE (messenger.conversations.selections.ellipsis):
+#  ellipsis is used when copying a part of a message to show that the message was cut
+messenger.conversations.selections.ellipsis=[…]
+
+# LOCALIZATION NOTE (messenger.conversations.selections.{system,content,action}MessagesTemplate):
+#  These 3 templates are used to format selected messages before copying them.
+#  Do not translate the texts between % characters, but feel free to adjust
+#  whitespace and separators to make them fit your locale.
+messenger.conversations.selections.systemMessagesTemplate=%time% - %message%
+messenger.conversations.selections.contentMessagesTemplate=%time% - %sender%: %message%
+messenger.conversations.selections.actionMessagesTemplate=%time% * %sender% %message%
+
+# LOCALIZATION NOTE (message.status):
+#  This is used as title attribute for the visible lock icon in case a message
+#  was sent encrypted through the OTR protocol.
+message.status=Neges wedi'i hamgryptio
diff --git a/l10n-cy/chat/dateFormat.properties b/l10n-cy/chat/dateFormat.properties
new file mode 100644
index 0000000000..2b65a477c2
--- /dev/null
+++ b/l10n-cy/chat/dateFormat.properties
@@ -0,0 +1,62 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+month.1.Mmm=Ion
+month.2.Mmm=Chw
+month.3.Mmm=Maw
+month.4.Mmm=Ebr
+month.5.Mmm=Mai
+month.6.Mmm=Meh
+month.7.Mmm=Gor
+month.8.Mmm=Awst
+month.9.Mmm=Medi
+month.10.Mmm=Hyd
+month.11.Mmm=Tach
+month.12.Mmm=Rhag
+
+month.1.name=Ionawr
+month.2.name=Chwefror
+month.3.name=Mawrth
+month.4.name=Ebrill
+month.5.name=Mai
+month.6.name=Mehefin
+month.7.name=Gorffennaf
+month.8.name=Awst
+month.9.name=Medi
+month.10.name=Hydref
+month.11.name=Tachwedd
+month.12.name=Rhagfyr
+
+day.1.name=Sul
+day.2.name=Llun
+day.3.name=Mawrth
+day.4.name=Mercher
+day.5.name=Iau
+day.6.name=Gwener
+day.7.name=Sadwrn
+
+day.1.Mmm=Sul
+day.2.Mmm=Llu
+day.3.Mmm=Maw
+day.4.Mmm=Mer
+day.5.Mmm=Iau
+day.6.Mmm=Gwe
+day.7.Mmm=Sad
+
+day.1.short=Su
+day.2.short=Ll
+day.3.short=Ma
+day.4.short=Me
+day.5.short=Ia
+day.6.short=Gw
+day.7.short=Sa
+
+noon=Hanner Dydd
+midnight=Hanner Nos
+
+AllDay=Drwy'r Dydd
+
+# LOCALIZATION NOTE (finduri-MonthYear):
+# %1$S is the month name, %2$S is the year (4 digits format).
+finduri-MonthYear=%1$S %2$S
diff --git a/l10n-cy/chat/facebook.properties b/l10n-cy/chat/facebook.properties
new file mode 100644
index 0000000000..ce8b168d02
--- /dev/null
+++ b/l10n-cy/chat/facebook.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+facebook.chat.name=Sgwrs Facebook
+facebook.disabled=Nid yw Facebook Chat yn cael ei gefnogi bellach wedi i Facebook analluogi eu porth XMPP.
diff --git a/l10n-cy/chat/imtooltip.properties b/l10n-cy/chat/imtooltip.properties
new file mode 100644
index 0000000000..c2f08b6497
--- /dev/null
+++ b/l10n-cy/chat/imtooltip.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+buddy.username=Enw Defnyddiwr
+buddy.account=Cyfrif
+contact.tags=Tagiau
+
+otr.tag=Statws OTR
+message.status=Neges wedi'i hamgryptio
diff --git a/l10n-cy/chat/irc.properties b/l10n-cy/chat/irc.properties
new file mode 100644
index 0000000000..904ec49cc7
--- /dev/null
+++ b/l10n-cy/chat/irc.properties
@@ -0,0 +1,209 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (irc.usernameHint):
+#  This is displayed inside the accountUsernameInfoWithDescription
+#  string defined in imAccounts.properties when the user is
+#  configuring an IRC account.
+irc.usernameHint=llysenw
+
+# LOCALIZATION NOTE (connection.error.*):
+#   These will show in the account manager if the account is
+#   disconnected because of an error.
+connection.error.lost=Wedi colli cysylltiad gyda'r gweinydd
+connection.error.timeOut=Cysylltiad wedi dod i ben
+connection.error.invalidUsername=Nid yw %S yn lysenw sy'n cael ei ganiatáu
+connection.error.invalidPassword=Cyfrinair gweinydd annilys
+connection.error.passwordRequired=Mae angen cyfrinair
+
+# LOCALIZATION NOTE (joinChat.*):
+#   These show up on the join chat menu. An underscore is for the access key.
+joinChat.channel=_Channel
+joinChat.password=_Password
+
+# LOCALIZATION NOTE (options.*):
+#   These are the protocol specific options shown in the account manager and
+#   account wizard windows.
+options.server=Gweinydd
+options.port=Porth
+options.ssl=Defnyddiwch SSL
+options.encoding=Set Nod
+options.quitMessage=Gadael neges
+options.partMessage=Rhan o neges
+options.showServerTab=Dangos negeseuon o'r gweinydd
+options.alternateNicks=Llysenw arall
+
+# LOCALIZATION NOTE (ctcp.version):
+#   %1$S is the nickname of the user whose version was requested.
+#   %2$S is the version response from the client.
+ctcp.version=Mae %1$S yn defnyddio "%2$S".
+# LOCALIZATION NOTE (ctcp.time):
+#   %1$S is the nickname of the user whose time was requested.
+#   %2$S is the time response.
+ctcp.time=Amser %1$S yw %2$S.
+
+# LOCALZIATION NOTE (command.*):
+#   These are the help messages for each command, the %S is the command name
+#   Each command first gives the parameter it accepts and then a description of
+#   the command.
+command.action=%S &lt;action to perform&gt;: Cyflawni gweithred.
+command.ban=%S &lt;nick!user@host&gt;: Atal y defnyddwyr sy'n cydweddu â'r patrwm penodol.
+command.ctcp=%S &lt;nick&gt; &lt;msg&gt;: Anfon neges CTCP i'r llysenw.
+command.chanserv=%S &lt;command&gt;: Anfon gorchymyn i ChanServ.
+command.deop=%S &lt;nick1&gt;[,&lt;nick2&gt;]*: Tynnu statws gweithredwr sianel oddi ar rhywun. Rhaid eich bod yn weithredwr sianel i wneud hynny.
+command.devoice=%S &lt;nick1&gt;[,&lt;nick2&gt;]*: Tynnu statws llais sianel oddi ar ehywun, eu hatal rhag siarad os yw'r sianel wedi ei gymedroli (+m). Rhaid eich bod yn weithredwr sianel i wneud hynny.
+command.invite2=%S &lt;nick&gt;[ &lt;nick&gt;]* [&lt;channel&gt;]: Gwahoddwch un neu fwy llysenw i ymuno â chi i'r sianel gyfredol neu sianel benodol.
+command.join=%S &lt;room1&gt;[ &lt;key1&gt;][,&lt;room2&gt;[ &lt;key2&gt;]]*: Ewch i un neu fwy o sianeli, gan ddarparu allwedd sianel i bob un yn ôl y dewis.
+command.kick=%S &lt;nick&gt; [&lt;message&gt;]: Tynnu rhywun o sianel. Rhaid eich bod yn reolwr sianel i wneud hyn.
+command.list=%S: Dangos rhestr o ystafelloedd sgwrsio ar y rhwydwaith. Rhybudd, gall rhai gweinyddion eich datgysylltu wrth wneud hyn.
+command.memoserv=%S &lt;command&gt;: Anfon gorchymyn i MemoServ.
+command.modeUser2=%S &lt;nick&gt; [(+|-)&lt;mode&gt;]: Estyn, gosod neu ddadosod modd y defnyddiwr.
+command.modeChannel2=%S [&lt;channel&gt;] [ (+|-)&lt;new mode&gt; [&lt;parameter&gt;][,&lt;parameter&gt;]*]: Estyn, gosod neu ddadosod modd sianel.
+command.msg=%S &lt;nick&gt; &lt;message&gt;: Anfon neges breifat i ddefnyddiwr (nid at sianel).
+command.nick=%S &lt;new nickname&gt;: Newid eich llysenw.
+command.nickserv=%S &lt;command&gt;: Anfon gorchymyn i NickServ.
+command.notice=%S &lt;target&gt; &lt;message&gt;: Anfon rhybudd at ddefnyddiwr neu sianel.
+command.op=%S &lt;nick1&gt;[,&lt;nick2&gt;]*: Rhoi statws gweithredwr sianel i rhywun. Rhaid eich bod yn reolwr sianel i wneud hyn.
+command.operserv=%S &lt;command&gt;: Anfon gorchymyn i OperServ.
+command.part=%S [message]: Gadael y sianel gyfredol gyda neges ddewisol.
+command.ping=%S [&lt;nick&gt;]: Gofyn faint o oedi sydd gan ddefnyddiwr (neu weinydd os nad oes defnyddiwr yn cael ei enwi).
+command.quit=%S &lt;message&gt;: Datgysylltu o'r gweinydd, gyda neges ddewisol.
+command.quote=%S &lt;command&gt;: Anfon gorchymyn bras i'r gweinydd.
+command.time=%S: dangos yr amser lleol cyfredol ar y gweinydd IRC.
+command.topic=%S [&lt;new topic&gt;]: Gosod pwnc y sianel.
+command.umode=%S (+|-)&lt;new mode&gt;: Gosod neu ddadosod modd defnyddiwr.
+command.version=%S &lt;nick&gt;: Gofyn am fersiwn cleient y defnyddiwr.
+command.voice=%S &lt;nick1&gt;[,&lt;nick2&gt;]*: Rhoi statws llais sianel i rhywun. Rhaid eich bod yn reolwr sianel i wneud hyn.
+command.whois2=%S [&lt;nick&gt;]: Derbyn gwybodaeth ar ddefnyddiwr.
+
+# LOCALIZATION NOTE (message.*):
+#    These are shown as system messages in the conversation.
+#    %1$S is the nick and %2$S is the nick and host of the user who joined.
+message.join=Mae %1$S [%2$S] wedi dod i mewn i'r ystafell.
+message.rejoined=Rydych wedi ailymuno â'r ystafell.
+#    %1$S is the nick of who kicked you.
+#    %2$S is message.kicked.reason, if a kick message was given.
+message.kicked.you=Rydych wedi cael eich cicio gan %1$S%2$S.
+#    %1$S is the nick that is kicked, %2$S the nick of the person who kicked
+#    %1$S. %3$S is message.kicked.reason, if a kick message was given.
+message.kicked=Mae %1$S wedi cael ei gicio gan %2$S%3$S.
+#    %S is the kick message
+message.kicked.reason=: %S
+#    %1$S is the new mode, %2$S is the nickname of the user whose mode
+#    was changed, and %3$S is who set the mode.
+message.usermode=Modd %1$S ar gyfer %2$S wedi'i osod gan %3$S.
+#    %1$S is the new channel mode and %2$S is who set the mode.
+message.channelmode=Modd sianel %1$S wedi ei osod gan %2$S.
+#    %S is the user's mode.
+message.yourmode=Eich modd yw %S.
+#    Could not change the nickname. %S is the user's nick.
+message.nick.fail=Nid oedd modd defnyddio'r llysenw penodol. Mae eich llysenw'n parhau'n %S.
+#    The parameter is the message.parted.reason, if a part message is given.
+message.parted.you=Rydych nawr wedi gadael yr ystafell (Part%1$S).
+#    %1$S is the user's nick, %2$S is message.parted.reason, if a part message is given.
+message.parted=Mae %1$S wedi gadael yr ystafell (Part%2$S).
+#    %S is the part message supplied by the user.
+message.parted.reason=: %S
+#    %1$S is the user's nick, %2$S is message.quit2 if a quit message is given.
+message.quit=Mae %1$S wedi gadael yr ystafell (Quit%2$S).
+#    The parameter is the quit message given by the user.
+message.quit2=: %S
+#    %1$S is the nickname of the user that invited us, %2$S is the conversation
+#    name.
+message.inviteReceived=Mae %1$S wedi eich gwahodd i %2$S.
+#    %1$S is the nickname of the invited user, %2$S is the conversation name
+#    they were invited to.
+message.invited=Cafodd %1$S ei wahodd yn llwyddiannus i %2$S.
+#    %1$S is the nickname of the invited user, %2$S is the conversation name
+#    they were invited to but are already in
+message.alreadyInChannel=Mae %1$S eisoes yn %2$S.
+#    %S is the nickname of the user who was summoned.
+message.summoned=Galwyd ar %S.
+#    %S is the nickname of the user whose WHOIS information follows this message.
+message.whois=Gwybodaeth WHOIS am %S:
+#    %1$S is the nickname of the (offline) user whose WHOWAS information follows this message.
+message.whowas=Mae %1$S all-lein. Gwybodaeth WHOWAS am %1$S:
+#    %1$S is the entry description (from tooltip.*), %2$S is its value.
+message.whoisEntry=\u00A0   %1$S: %2$S
+#    %S is the nickname that is not known to the server.
+message.unknownNick=Mae %S yn llysenw anhysbys.
+#    %1$S is the nickname of the user who changed the mode and %2$S is the new
+#    channel key (password).
+message.channelKeyAdded=Mae %1$S wedi newid cyfrinair y sianel i %2$S.
+message.channelKeyRemoved=Mae %S wedi tynnu cyfrinair y sianel.
+#    This will be followed by a list of ban masks.
+message.banMasks=Mae defnyddwyr wedi eu cysylltu o'r lleoliadau canlynol wedi eu hatal o %S:
+message.noBanMasks=Nid oes lleoliadau wedi eu hatal ar gyfer %S.
+message.banMaskAdded=Mae defnyddwyr wedi eu cysylltu o lleoliadau tebyg i %1$S wedi eu hatal gan %2$S.
+message.banMaskRemoved=Nid yw defnyddwyr sydd wedi eu cysylltu o lleoliadau tebyg i %1$S wedi eu hatal bellach gan %2$S.
+# LOCALIZATION NOTE (message.ping): Semi-colon list of plural forms.
+#  See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+#   %1$S is the nickname of the user or the server that was pinged.
+#   #2 is the delay (in milliseconds).
+message.ping=Peidio pingio atebion.;Pingio ateb o %1$S mewn #2 milfed eiliad.;Pingio ateb o %1$S mewn #2 milfed eiliad.;Pingio ateb o %1$S mewn #2 milfed eiliad.;Pingio ateb o %1$S mewn #2 milfed eiliad.;Pingio ateb o %1$S mewn #2 milfed eiliad.
+
+
+# LOCALIZATION NOTE (error.*):
+#    These are shown as error messages in the conversation or server tab.
+#    %S is the channel name.
+error.noChannel=Nid oes sianel: %S.
+error.tooManyChannels=Methu ymuno â %S; rydych wedi ymuno â gormod o sianeli.
+#    %1$S is your new nick, %2$S is the kill message from the server.
+error.nickCollision=Mae'r llysenw'n cael ei ddefnyddio eisoes, newid y llysenw i %1$S [%2$S].
+error.erroneousNickname=Nid yw %S yn lysenw sy'n cael ei ganiatáu.
+error.banned=Rydych wedi'ich gwahardd o'r sianel.
+error.bannedSoon=Byddwch yn cael eich gwahardd o'r gweinydd hwn cyn bo hir.
+error.mode.wrongUser=Nid oes modd i chi newid moddau ar gyfer defnyddwyr eraill.
+#    %S is the nickname or channel name that isn't available.
+error.noSuchNick=Nid yw %S ar-lein.
+error.wasNoSuchNick=Nid oes llysenw: %S
+error.noSuchChannel=Nid oes sianel: %S.
+error.unavailable=Nid yw %S ar gael ar hyn o bryd.
+#    %S is the channel name.
+error.channelBanned=Rydych wedi eich atal rhag %S.
+error.cannotSendToChannel=Nid oes modd anfon negeseuon at %S.
+error.channelFull=Mae sianel %S yn llawn.
+error.inviteOnly=Rhaid derbyn gwahoddiad i ymuno â %S.
+error.nonUniqueTarget=Nid yw %S yn user@host neu enw byr unigryw neu rydych wedi ceisio ymuno â gormod o sianeli ar un waith.
+error.notChannelOp=Nid chi yw'r gweithredwr sianel ar %S.
+error.notChannelOwner=Nid chi yw perchennog sianel %S.
+error.wrongKey=Methu ymuno â %S, cyfrinair sianel annilys.
+error.sendMessageFailed=Digwyddodd gwall wrth anfon eich neges diwethaf. Ceisiwch eto unwaith y bydd y cysylltiad wedi ei ailosod.
+#    %1$S is the channel the user tried to join, %2$S is the channel
+#    he was forwarded to.
+error.channelForward=Nid oes modd i chi ymuno â %1$S, ac rydych wedi eich ailgyfeirio i %2$S.
+#    %S is the mode that the user tried to set but was not recognized
+#    by the server as a valid mode.
+error.unknownMode=Nid yw '%S' yn fodd defnyddiwr dilys ar y gweinydd hwn.
+
+# LOCALIZATION NOTE (tooltip.*):
+#    These are the descriptions given in a tooltip with information received
+#    from a whois response.
+#    The human readable ("realname") description of the user.
+tooltip.realname=Enw
+tooltip.server=Cysylltwyd i
+#    The username and hostname that the user connects from (usually based on the
+#    reverse DNS of the user's IP, but often mangled by the server to
+#    protect users).
+tooltip.connectedFrom=Cysylltwyd o
+tooltip.registered=Cofrestredig
+tooltip.registeredAs=Cofrestrwyd fel
+tooltip.secure=Defnyddio cysylltiad diogel
+# The away message of the user
+tooltip.away=I Ffwrdd
+tooltip.ircOp=Gweithredwr IRC
+tooltip.bot=Bot
+tooltip.lastActivity=Gweithgaredd diwethaf
+# %S is the timespan elapsed since the last activity.
+tooltip.timespan=%S yn ôl
+tooltip.channels=Yn gyfredol ar
+
+#    %1$S is the server name, %2$S is some generic server information (usually a
+#    location or the date the user was last seen).
+tooltip.serverValue=%1$S (%2$S)
+
+# LOCALIZATION NOTE (yes, no):
+#  These are used to turn true/false values into a yes/no response.
+yes=Iawn
+no=Na
diff --git a/l10n-cy/chat/logger.properties b/l10n-cy/chat/logger.properties
new file mode 100644
index 0000000000..4139a46ced
--- /dev/null
+++ b/l10n-cy/chat/logger.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (badLogfile):
+#  %S is the filename of the log file.
+badLogfile=Ffeil cofnodi gwag neu llwgr:: %S
diff --git a/l10n-cy/chat/matrix.properties b/l10n-cy/chat/matrix.properties
new file mode 100644
index 0000000000..ea79782c2b
--- /dev/null
+++ b/l10n-cy/chat/matrix.properties
@@ -0,0 +1,26 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (options.*):
+#   These are the protocol specific options shown in the account manager and
+#   account wizard windows.
+options.connectServer=Gweinydd
+options.connectPort=Porth
+
+# LOCALIZATION NOTE (chatRoomField.*):
+#   These are the name of fields displayed in the 'Join Chat' dialog
+#   for Matrix accounts.
+#   The _ character won't be displayed; it indicates the next
+#   character of the string should be used as the access key for this
+#   field.
+chatRoomField.room=_Ystafell
+
+# LOCALIZATION NOTE (tooltip.*):
+#    These are the descriptions given in a tooltip with information received
+#    from the "User" object.
+# The human readable name of the user.
+tooltip.displayName=Dangos enw
+# %S is the timespan elapsed since the last activity.
+tooltip.timespan=%S yn ôl
+tooltip.lastActive=Gweithgaredd diwethaf
diff --git a/l10n-cy/chat/skype.properties b/l10n-cy/chat/skype.properties
new file mode 100644
index 0000000000..4cab828044
--- /dev/null
+++ b/l10n-cy/chat/skype.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (connection.*):
+#   These will show in the account manager to show progress during a connection.
+connecting.authenticating=Dilysu
+connecting.registrationToken=Estyn tocyn cofrestru
+
+# LOCALIZATION NOTE (error.*):
+#   These will show in the account manager if the account is disconnected
+#   because of an error.
+error.auth=Methwyd dilysu i'r gweinydd
+error.registrationToken=Methwyd estyn Tocyn Cofrestru
diff --git a/l10n-cy/chat/status.properties b/l10n-cy/chat/status.properties
new file mode 100644
index 0000000000..e72248faef
--- /dev/null
+++ b/l10n-cy/chat/status.properties
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+availableStatusType=Ar Gael
+awayStatusType=I Ffwrdd
+unavailableStatusType=Ddim ar Gael
+offlineStatusType=All-lein
+invisibleStatusType=Anweledig
+idleStatusType=Segur
+mobileStatusType=Ffôn Symudol
+# LOCALIZATION NOTE (unknownStatusType):
+# the status of a buddy is unknown when it's in the list of a disconnected account
+unknownStatusType=Anhysbys
+
+# LOCALIZATION NOTE (statusWithStatusMessage):
+# Used to display the status of a buddy together with its status message.
+# %1$S is the status type, %2$S is the status message text.
+statusWithStatusMessage=%1$S - %2$S
+
+# LOCALIZATION NOTE (messenger.status.defaultIdleAwayMessage):
+#  This will be the away message put automatically when the user is idle.
+messenger.status.defaultIdleAwayMessage=Nid wyf wrth fy nghyfrifiadur ar hyn o bryd.
diff --git a/l10n-cy/chat/twitter.properties b/l10n-cy/chat/twitter.properties
new file mode 100644
index 0000000000..c5733c5b7c
--- /dev/null
+++ b/l10n-cy/chat/twitter.properties
@@ -0,0 +1,122 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (twitter.protocolName)
+#  This name is used whenever the name of the protocol is shown.
+twitter.protocolName=Twitter
+
+# LOCALIZATION NOTE (error.*):
+#   These are errors that will be shown to the user in conversation.
+error.tooLong=Mae statws dros 140 nod.
+# LOCALIZATION NOTE (error.general, error.retweet, error.delete):
+#   %1$S will be either the error string returned by the twitter server,
+#   in English, inside parenthesis, or the empty string if we have no specific
+#   message for the error.
+#   %2$S is the message that caused the error.
+error.general=Digwyddodd gwall %1$S wrth anfon: %2$S
+error.retweet=Digwyddodd gwall %1$S wrth aildrydar: %2$S
+error.delete=Digwyddodd gwall %1$S wrth ddileu: %2$S
+error.like=Digwyddodd gwall %1$S wrth hoffi: %2$S
+error.unlike=Digwyddodd gwall %1$S wrth ddadhoffi: %2$S
+# LOCALIZATION NOTE (error.descriptionTooLong)
+#   %S is the truncated string that was sent to the server.
+error.descriptionTooLong=Mae'r disgrifiad yn hirach na'r hyd mwyaf (160 nod), cafodd ei fyrhau'n awtomatig i: %S.
+
+# LOCALIZATION NOTE (timeline):
+#   This is the title of the conversation tab, %S will be replaced by
+#   @<username>.
+timeline=Llinell amser %S
+
+# LOCALIZATION NOTE (action.*):
+#  This will be an action in the context menu of displayed tweets.
+action.copyLink=Copïo Dolen i Drydar
+action.retweet=Aildrydar
+action.reply=Ateb
+action.delete=Dileu
+# LOCALIZATION NOTE (action.follow, action.stopFollowing):
+#  %S will be replaced by the screen name of a twitter user.
+action.follow=Dilyn %S
+action.stopFollowing=Peidio dilyn %S
+action.like=Hoffi
+action.unlike=Tynnu Hoffi
+
+# LOCALIZATION NOTE (event.follow, event.unfollow, event.followed):
+#  This will be displayed in system messages inside the timeline conversation.
+#  %S will be replaced by the screen name of a twitter user.
+event.follow=Rydych nawr yn dilyn %S.
+event.unfollow=Nid ydych bellach yn dilyn %S.
+event.followed=Mae %S yn eich dilyn chi.
+# LOCALIZATION NOTE (event.deleted):
+#  %S will be replaced by the text of the deleted tweet.
+event.deleted=Rydych wedi dileu'r trydariad: "%S".
+
+# LOCALIZATION NOTE (replyingToStatusText):
+#  This will be visible in the status bar of the conversation window
+#  while the user is typing a reply to a tweet.
+#  %S will be replaced by the text of the tweet the user is replying to.
+replyingToStatusText=Ateb: %S
+
+# LOCALIZATION NOTE (connection.*):
+#   These will be displayed in the account manager in order to show the progress
+#   of the connection.
+#   (These will be displayed in account.connection.progress from
+#    accounts.properties, which adds … at the end, so do not include
+#    periods at the end of these messages.)
+connection.initAuth=Cychwyn y broses dilysu
+connection.requestAuth=Aros am eich dilysiad
+connection.requestAccess=Cwblhau'r dilysu
+connection.requestTimelines=Gofyn am llinellau amser defnyddiwr
+# LOCALIZATION NOTE (connection.error.*):
+#   These will show in the account manager if an error occurs during the
+#   connection attempt.
+connection.error.userMismatch=Anghydweddiad enw defnyddiwr.
+connection.error.failedToken=Methu cael tocyn cais.
+connection.error.authCancelled=Rydych wedi diddymu'r broses dilysu.
+connection.error.authFailed=Methu derbyn dilysiad.
+connection.error.noNetwork=Nid oes cysylltiad rhwydwaith ar gael.
+
+# LOCALIZATION NOTE (authPrompt):
+#   This is the prompt in the browser window that pops up to authorize us
+#   to use a Twitter account. It is shown in the title bar of the authorization
+#   window.
+authPrompt=Rhoi eich caniatâd i ddefnyddio eich cyfrif Twitter
+
+# LOCALIZATION NOTE (options.*):
+#   These are the protocol specific options shown in the account manager and
+#   account wizard windows.
+options.track=Allweddeiriau wedi'u tracio
+
+# LOCALIZATION NOTE (tooltip.*):
+#   These are the Twitter information that will appear in the tooltip
+#   for each participant on the home timeline.
+# LOCALIZATION NOTE (tooltip.created_at): the date the user joined.
+tooltip.created_at=Defnyddiwr Ers
+tooltip.location=Lleoliad
+tooltip.lang=Iaith
+tooltip.time_zone=Cylchamser
+tooltip.url=Tudalen Cartref
+# LOCALIZATION NOTE (tooltip.protected):
+#  whether the user's tweets are publicly visible.
+tooltip.protected=Diogelu Trydar
+# LOCALIZATION NOTE (tooltip.following):
+#  whether you are subscribed to the user's tweets.
+tooltip.following=Yn Dilyn ar Hyn o Bryd
+tooltip.name=Enw
+tooltip.description=Disgrifiad
+# LOCALIZATION NOTE (tooltip.*_count):
+#  Please see the right side of the official Twitter website UI.
+tooltip.friends_count=Dilyn
+tooltip.statuses_count=Trydar
+tooltip.followers_count=Dilynwyr
+tooltip.listed_count=Rhestrwyd
+
+# LOCALIZATION NOTE (yes, no):
+#  These are used to turn true/false values into a yes/no response.
+yes=Iawn
+no=Na
+
+command.follow=%S &lt;username&gt;[ &lt;username&gt;]*: Cychwynnwch ddilyn defnyddiwr / defnyddwyr.
+command.unfollow=%S &lt;username&gt;[ &lt;username&gt;]*: Rhowch y gorau i ddilyn defnyddiwr / defnyddwyr.
+
+twitter.disabled=Nid yw Twitter yn cael ei gefnogi bellach oherwydd bod Twitter wedi analluogi eu protocol ffrydio.
diff --git a/l10n-cy/chat/xmpp.properties b/l10n-cy/chat/xmpp.properties
new file mode 100644
index 0000000000..5b5abe3875
--- /dev/null
+++ b/l10n-cy/chat/xmpp.properties
@@ -0,0 +1,276 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (connection.*)
+#   These will be displayed in the account manager in order to show the progress
+#   of the connection.
+#   (These will be displayed in account.connection.progress from
+#    accounts.properties, which adds … at the end, so do not include
+#    periods at the end of these messages.)
+connection.initializingStream=Cychwyn llif
+connection.initializingEncryption=Cychwyn amgryptio
+connection.authenticating=Dilysu
+connection.gettingResource=Derbyn adnoddau
+connection.downloadingRoster=Llwytho rhestr cyswllt i lawr
+connection.srvLookup=Archwilio'r cofnod SRV
+
+# LOCALIZATION NOTE (connection.error.*)
+#   These will show in the account manager if an error occurs during the
+#   connection attempt.
+connection.error.invalidUsername=Enw defnyddiwr annilys (rhaid i'ch enw defnyddiwr gynnwys y nod '@')
+connection.error.failedToCreateASocket=Methwyd â chreu soced (Ydych chi all-lein?)
+connection.error.serverClosedConnection=Mae'r gweinydd wedi cau'r cysylltiad
+connection.error.resetByPeer=Mae'r cysylltiad wedi'i ailosod gan gyfoedion
+connection.error.timedOut=Daeth cyfnod y cysylltiad i ben
+connection.error.receivedUnexpectedData=Wedi derbyn data annisgwyl
+connection.error.incorrectResponse=Wedi derbyn ymateb anghywir
+connection.error.startTLSRequired=Mae'r gweinydd angen amgryptiad ond rydych wedi'i anablu
+connection.error.startTLSNotSupported=Nid yw'r gweinydd yn cynnal amgryptiad ond mae eich ffurfweddiad ei angen
+connection.error.failedToStartTLS=Methwyd â chychwyn amgryptiad
+connection.error.noAuthMec=Nid yw'r gweinydd yn cynnig peirianwaith dilysu
+connection.error.noCompatibleAuthMec=Nid oes yr un o'r dulliau amgryptio mae'r gweinydd yn eu cynnig yn cael eu cynnal
+connection.error.notSendingPasswordInClear=Dim ond amgryptiad drwy anfon cyfrinair mewn cleartext sy'n cael ei gynnal gan y gweinydd
+connection.error.authenticationFailure=Methu dilysu
+connection.error.notAuthorized=Dim awdurdod (Cyfrinair anghywir?)
+connection.error.failedToGetAResource=Methu estyn adnodd
+connection.error.failedMaxResourceLimit=Mae'r cyfrif wedi ei gysylltu o ormod o fannau ar yr un pryd.
+connection.error.failedResourceNotValid=Nid yw'r adnodd yn ddilys.
+connection.error.XMPPNotSupported=Nid yw'r gweinydd yn cynnal XMPP
+
+# LOCALIZATION NOTE (conversation.error.notDelivered):
+#   This is displayed in a conversation as an error message when a message
+#   the user has sent wasn't delivered.
+#   %S is replaced by the text of the message that wasn't delivered.
+conversation.error.notDelivered=Nid oedd modd trosglwyddo'r neges hon: %S
+#   This is displayed in a conversation as an error message when joining a MUC
+#   fails.
+#   %S is the name of the MUC.
+conversation.error.joinFailed=Methu ymuno: %S
+#   This is displayed in a conversation as an error message when the user is
+#   banned from a room.
+#   %S is the name of the MUC room.
+conversation.error.joinForbidden=Methu ymuno â %S gan eich bod wedi eich atal o'r ystafell.
+conversation.error.joinFailedNotAuthorized=Mae angen cofrestru: Does gennych ddim hawl i ymuno â'r ystafell hon.
+conversation.error.creationFailedNotAllowed=Mynediad wedi ei gyfyngu: Nid oes gennych hawl i greu ystafelloedd.
+#   This is displayed in a conversation as an error message when remote server
+#   is not found.
+#   %S is the name of MUC room.
+conversation.error.joinFailedRemoteServerNotFound=Methu ymuno ag ystafell %S gan nad oedd modd cysylltu â'r gweinydd mae'r ystafell arni.
+conversation.error.changeTopicFailedNotAuthorized=Nid oes gennych hawl i osod pwnc yn yr ystafell hon.
+#   This is displayed in a conversation as an error message when the user sends
+#   a message to a room that he is not in.
+#   %1$S is the name of MUC room.
+#   %2$S is the text of the message that wasn't delivered.
+conversation.error.sendFailedAsNotInRoom=Nid oedd modd anfon at %1$S gan nad ydych bellach yn yr ystafell: %2$S
+#   This is displayed in a conversation as an error message when the user sends
+#   a message to a room that the recipient is not in.
+#   %1$S is the jid of the recipient.
+#   %2$S is the text of the message that wasn't delivered.
+conversation.error.sendFailedAsRecipientNotInRoom=Nid oedd modd anfon at %1$S gan nad yw'r derbynnydd bellach yn yr ystafell: %2$S
+#   These are displayed in a conversation as a system error message.
+conversation.error.remoteServerNotFound=Methu cyrraedd gweinydd y derbynnydd.
+conversation.error.unknownSendError=Digwyddodd gwall anhysbys wrth anfon y neges hon.
+#   %S is the name of the message recipient.
+conversation.error.sendServiceUnavailable=Nid yw'n bosib anfon negeseuon at %S ar hyn o bryd.
+#   %S is the nick of participant that is not in room.
+conversation.error.nickNotInRoom=Nis yw %S yn yr ystafell.
+conversation.error.banCommandAnonymousRoom=Nid oes modd i chi atal y sawl sy'n cymryd rhan mewn ystafell ddienw. Defnyddiwch /kick yn lle hynny.
+conversation.error.banKickCommandNotAllowed=Nid oes gennych y breintiau angenrheidiol i dynnu'r unigolyn yma o'r ystafell.
+conversation.error.banKickCommandConflict=Nid oes modd i chi dynnu eich hun o'r ystafell.
+conversation.error.changeNickFailedConflict=Methu newid eich llys enw i %S gan ei fod eisoes yn cael ei ddefnyddio.
+conversation.error.changeNickFailedNotAcceptable=Methu newid eich llys enw i %S gan fod llys enwau wedi eu cloi lawr yn yr ystafell hon.
+conversation.error.inviteFailedForbidden=Nid oes gennych y breintiau angenrheidiol i wahodd defnyddwyr i'r ystafell.
+#   %S is the jid of user that is invited.
+conversation.error.failedJIDNotFound=Methu cyrraedd %S.
+#   %S is the jid that is invalid.
+conversation.error.invalidJID=Mae %S yn jib annilys (Rhaid i enwau Jabber fod ar ffurf defnyddiwr@parth).
+conversation.error.commandFailedNotInRoom=Rhaid i chi ailymuno a'r ystafell i ddefnyddio'r gorchymyn yma.
+#   %S is the name of the recipient.
+conversation.error.resourceNotAvailable=Rhaid i chi siarad yn gyntaf fel bod %S yn gallu bod wedi cysylltu â mwy nag un cleient.
+
+# LOCALIZATION NOTE (conversation.error.version.*):
+#   %S is the name of the recipient.
+conversation.error.version.unknown=Nid yw'r cleient %S yn cynnal ymholi i'w fersiwn meddalwedd.
+
+# LOCALIZATION NOTE (tooltip.*):
+#   These are the titles of lines of information that will appear in
+#   the tooltip showing details about a contact or conversation.
+# LOCALIZATION NOTE (tooltip.status):
+#   %S will be replaced by the XMPP resource identifier
+tooltip.status=Statws (%S)
+tooltip.statusNoResource=Statws
+tooltip.subscription=Tanysgrifiad
+tooltip.fullName=Enw Llawn
+tooltip.nickname=Llysenw
+tooltip.email=E-bost
+tooltip.birthday=Pen-blwydd
+tooltip.userName=Enw Defnyddiwr
+tooltip.title=Teitl
+tooltip.organization=Corff
+tooltip.locality=Lleolad
+tooltip.country=Gwlad
+
+tooltip.telephone=Rhif ffôn
+
+# LOCALIZATION NOTE (chatRoomField.*):
+#   These are the name of fields displayed in the 'Join Chat' dialog
+#   for XMPP accounts.
+#   The _ character won't be displayed; it indicates the next
+#   character of the string should be used as the access key for this
+#   field.
+chatRoomField.room=_Room
+chatRoomField.server=_Server
+chatRoomField.nick=_Nick
+chatRoomField.password=_Password
+
+# LOCALIZATION NOTE (conversation.muc.*):
+#   These are displayed as a system message when a chatroom invitation is
+#   received.
+#   %1$S is the inviter.
+#   %2$S is the room.
+#   %3$S is the reason which is a message provided by the person sending the
+#   invitation.
+conversation.muc.invitationWithReason2=Mae %1$S wedi eich gwahodd i ymuno â %2$S: %3$S
+#   %3$S is the password of the room.
+#   %4$S is the reason which is a message provided by the person sending the
+#   invitation.
+conversation.muc.invitationWithReason2.password=Mae %1$S wedi eich gwahodd i ymuno â %2$S gyda'r cyfrinair %3$S: %4$S
+conversation.muc.invitationWithoutReason=Mae %1$S wedi eich gwahodd i ymuno â %2$S
+#   %3$S is the password of the room.
+conversation.muc.invitationWithoutReason.password=Mae %1$S wedi eich gwahodd i ymuno â %2$S gyda'r cyfrinair %3$S
+
+# LOCALIZATION NOTE (conversation.muc.join):
+#   This is displayed as a system message when a participant joins room.
+#   %S is the nick of the participant.
+conversation.message.join=Mae %S wedi dod i'r ystafell.
+
+# LOCALIZATION NOTE (conversation.muc.rejoined):
+#   This is displayed as a system message when a participant rejoins room after
+#   parting it.
+conversation.message.rejoined=Rydych wedi ailymuno â'r ystafell.
+
+# LOCALIZATION NOTE (conversation.message.parted.*):
+#   These are displayed as a system message when a participant parts a room.
+#   %S is the part message supplied by the user.
+conversation.message.parted.you=Rydych wedi gadael yr ystafell.
+conversation.message.parted.you.reason=Rydych wedi gadael yr ystafell: %S
+#   %1$S is the participant that is leaving.
+#   %2$S is the part message supplied by the participant.
+conversation.message.parted=Mae %1$S wedi gadael yr ystafell.
+conversation.message.parted.reason=Mae %1$S wedi gadael yr ystafell: %2$S
+
+# LOCALIZATION NOTE (conversation.message.invitationDeclined*):
+#   %1$S is the invitee that declined the invitation.
+#   %2$S is the decline message supplied by the invitee.
+conversation.message.invitationDeclined=Mae %1$S wedi gwrthod eich gwahoddiad.
+conversation.message.invitationDeclined.reason=Mae %1$S wedi gwrthod eich gwahoddiad: %2$S
+
+# LOCALIZATION NOTE (conversation.message.banned.*):
+#   These are displayed as a system message when a participant is banned from
+#   a room.
+#   %1$S is the participant that is banned.
+#   %2$S is the reason.
+#   %3$S is the person who is banning.
+conversation.message.banned=Mae %1$S wedi ei atal o'r ystafell.
+conversation.message.banned.reason=Mae %1$S wedi ei atal o'r ystafell: %2$S
+#   %1$S is the person who is banning.
+#   %2$S is the participant that is banned.
+#   %3$S is the reason.
+conversation.message.banned.actor=Mae %1$S wedi gwahardd %2$S o'r ystafell.
+conversation.message.banned.actor.reason=Mae %1$S wedi gwahardd %2$S o'r ystafell: %3$S
+conversation.message.banned.you=Rydych wedi eich gwahardd o'r ystafell.
+#   %1$S is the reason.
+conversation.message.banned.you.reason=Rydych wedi eich gwahardd o'r ystafell: %1$S
+#   %1$S is the person who is banning.
+#   %2$S is the reason.
+conversation.message.banned.you.actor=Mae %1$S wedi eich gwahardd o'r ystafell.
+conversation.message.banned.you.actor.reason=Mae %1$S wedi eich gwahardd o'r ystafell: %2$S
+
+# LOCALIZATION NOTE (conversation.message.kicked.*):
+#   These are displayed as a system message when a participant is kicked from
+#   a room.
+#   %1$S is the participant that is kicked.
+#   %2$S is the reason.
+conversation.message.kicked=Mae %1$S wedi cael ei gicio o'r ystafell.
+conversation.message.kicked.reason=Mae %1$S wedi ei gicio o'r ystafell: %2$S
+#   %1$S is the person who is kicking.
+#   %2$S is the participant that is kicked.
+#   %3$S is the reason.
+conversation.message.kicked.actor=Mae %1$S wedi cicio %2$S o'r ystafell.
+conversation.message.kicked.actor.reason=Mae %1$S wedi cicio %2$S o'r ystafell: %3$S
+conversation.message.kicked.you=Rydych wedi cael eich cicio o'r ystafell.
+#   %1$S is the reason.
+conversation.message.kicked.you.reason=Rydych wedi cael eich cicio o'r ystafell: %1$S
+#   %1$S is the person who is kicking.
+#   %2$S is the reason.
+conversation.message.kicked.you.actor=Mae %1$S wedi eich cicio chi o'r ystafell.
+conversation.message.kicked.you.actor.reason=Mae %1$S wedi eich cicio chi o'r ystafell: %2$S
+
+# LOCALIZATION NOTE (conversation.message.removedNonMember.*):
+#   These are displayed as a system message when a participant is removed from
+#   a room because the room has been changed to members-only.
+#   %1$S is the participant that is removed.
+#   %2$S is the person who changed the room configuration.
+conversation.message.removedNonMember=Mae %1$S wedi ei dynnu o'r ystafell gan fod y ffurfweddiad wedi ei newid i aelodau'n unig.
+conversation.message.removedNonMember.actor=Mae %1$S wedi ei dynnu o'r ystafell gan fod %2$S wedi ei newid i aelodau'n unig.
+conversation.message.removedNonMember.you=Rydych wedi eich tynnu o'r ystafell gan fod y ffurfweddiad wedi ei newid i aelodau'n unig.
+#   %1$S is the person who changed the room configuration.
+conversation.message.removedNonMember.you.actor=Rydych wedi eich tynnu o'r ystafell gan fod %1$S wedi ei newid i aelodau'n unig.
+
+# LOCALIZATION NOTE (conversation.message.MUCShutdown):
+#   These are displayed as a system message when a participant is removed from
+#   a room because of a system shutdown.
+conversation.message.mucShutdown=Rydych wedi eich tynnu o'r ystafell gan fod y system wedi ei gau i lawr.
+
+# LOCALIZATION NOTE (conversation.message.version*):
+#   %1$S is the name of the user whose version was requested.
+#   %2$S is the client name response from the client.
+#   %3$S is the client version response from the client.
+#   %4$S is the operating system(OS) response from the client.
+conversation.message.version=Mae %1$S yn defnyddio "%2$S %3$S".
+conversation.message.versionWithOS=Mae %1$S yn defnyddio "%2$S %3$S" ar %4$S.
+
+# LOCALIZATION NOTE (options.*):
+#   These are the protocol specific options shown in the account manager and
+#   account wizard windows.
+options.resource=Adnodd
+options.priority=Blaenoriaeth
+options.connectionSecurity=Diogelwch cysylltiad
+options.connectionSecurity.requireEncryption=Gofyn am amgryptiad
+options.connectionSecurity.opportunisticTLS=Defnyddio amgryptiad os yw ar gael
+options.connectionSecurity.allowUnencryptedAuth=Caniatáu anfon y cyfrinair heb amgryptiad
+options.connectServer=Gweinydd
+options.connectPort=Porth
+options.domain=Parth
+
+# LOCALIZATION NOTE (*.protocolName)
+#  This name is used whenever the name of the protocol is shown.
+gtalk.protocolName=Google Talk
+odnoklassniki.protocolName=Odnoklassniki
+
+# LOCALIZATION NOTE (gtalk.usernameHint):
+#  This is displayed inside the accountUsernameInfoWithDescription
+#  string defined in imAccounts.properties when the user is
+#  configuring a Google Talk account.
+gtalk.usernameHint=cyfeiriad e-bost
+
+# LOCALIZATION NOTE (odnoklassniki.usernameHint):
+#  This is displayed inside the accountUsernameInfoWithDescription
+#  string defined in imAccounts.properties when the user is
+#  configuring a Odnoklassniki account.
+odnoklassniki.usernameHint=Enw Proffil
+
+# LOCALZIATION NOTE (command.*):
+#  These are the help messages for each command.
+command.join3=%S [&lt;room&gt;[@&lt;server&gt;][/&lt;nick&gt;]] [&lt;password&gt;]: Ymunwch ag ystafell, o ddewis yn darparu gweinydd gwahanol neu lysenw neu gyfrinair ystafell.
+command.part2=%S [&lt;message&gt;]: Gadael y sianel gyfredol gydag neges ddewisol.
+command.topic=%S [&lt;new topic&gt;]: Gosod pwnc yr ystafell.
+command.ban=%S &lt;nick&gt;[&lt;message&gt;]: Gwahardd rhywun o'r ystafell. Rhaid eich bod yn weinyddwr yr ystafell i wneud hynny.
+command.kick=%S &lt;nick&gt;[&lt;message&gt;]: Tynnu rhywun o'r ystafell. Rhaid eich bod yn gymedrolwr ystafell i wneud hynny.
+command.invite=%S &lt;jid&gt;[&lt;message&gt;]: Gwahodd defnyddiwr i ymuno a'r ystafell gyfredol gyda neges ddewisol.
+command.inviteto=%S &lt;room jid&gt;[&lt;password&gt;]: Gwahoddwch eich partner sgwrsio i ymuno â'r ystafell, ynghyd â'r cyfrinair os oes angen.
+command.me=%S &lt;action to perform&gt;: Cyflawni gweithred.
+command.nick=%S &lt;new nickname&gt;: Newid eich llysenw.
+command.msg=%S &lt;nick&gt; &lt;message&gt;: Anfonwch neges breifat at rywun sy'n cymryd rhan yn yr ystafell.
+command.version=%S: Gofynnwch am wybodaeth am y cleient mae eich partner sgwrsio yn ei ddefnyddio.
diff --git a/l10n-cy/chat/yahoo.properties b/l10n-cy/chat/yahoo.properties
new file mode 100644
index 0000000000..9ff73652e3
--- /dev/null
+++ b/l10n-cy/chat/yahoo.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+yahoo.disabled=Nid yw Yahoo Messenger'n cael ei gynnal bellach wedi i Yahoo analluogi eu hen protocol.
diff --git a/l10n-cy/devtools/client/aboutdebugging.ftl b/l10n-cy/devtools/client/aboutdebugging.ftl
new file mode 100644
index 0000000000..afb9490a08
--- /dev/null
+++ b/l10n-cy/devtools/client/aboutdebugging.ftl
@@ -0,0 +1,394 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used inside the about:debugging UI.
+
+
+# Page Title strings
+
+# Page title (ie tab title) for the Setup page
+about-debugging-page-title-setup-page = Dadfygio - Gosod
+
+# Page title (ie tab title) for the Runtime page
+# { $selectedRuntimeId } is the id of the current runtime, such as "this-firefox", "localhost:6080", ...
+about-debugging-page-title-runtime-page = Dadfygio - Amser Rhedeg/ { $selectedRuntimeId }
+
+# Sidebar strings
+
+# Display name of the runtime for the currently running instance of Firefox. Used in the
+# Sidebar and in the Setup page.
+about-debugging-this-firefox-runtime-name = Y { -brand-shorter-name } hwn
+
+# Sidebar heading for selecting the currently running instance of Firefox
+about-debugging-sidebar-this-firefox =
+    .name = { about-debugging-this-firefox-runtime-name }
+
+# Sidebar heading for connecting to some remote source
+about-debugging-sidebar-setup =
+    .name = Gosod
+
+# Text displayed in the about:debugging sidebar when USB devices discovery is enabled.
+about-debugging-sidebar-usb-enabled = USB wedi'i alluogi
+
+# Text displayed in the about:debugging sidebar when USB devices discovery is disabled
+# (for instance because the mandatory ADB extension is not installed).
+about-debugging-sidebar-usb-disabled = USB wedi ei analluogi
+
+# Connection status (connected) for runtime items in the sidebar
+aboutdebugging-sidebar-runtime-connection-status-connected = Cysylltwyd
+# Connection status (disconnected) for runtime items in the sidebar
+aboutdebugging-sidebar-runtime-connection-status-disconnected = Datgysylltwyd
+
+# Text displayed in the about:debugging sidebar when no device was found.
+about-debugging-sidebar-no-devices = Heb ddarganfod unrhyw ddyfeisiau
+
+# Text displayed in buttons found in sidebar items representing remote runtimes.
+# Clicking on the button will attempt to connect to the runtime.
+about-debugging-sidebar-item-connect-button = Cysylltu
+
+# Text displayed in buttons found in sidebar items when the runtime is connecting.
+about-debugging-sidebar-item-connect-button-connecting = Cysylltu…
+
+# Text displayed in buttons found in sidebar items when the connection failed.
+about-debugging-sidebar-item-connect-button-connection-failed = Methodd y cysylltiad
+
+# Text displayed in connection warning on sidebar item of the runtime when connecting to
+# the runtime is taking too much time.
+about-debugging-sidebar-item-connect-button-connection-not-responding = Cysylltiad yn yr arfaeth o hyd, gwiriwch am negeseuon ar y porwr targed
+
+# Text displayed as connection error in sidebar item when the connection has timed out.
+about-debugging-sidebar-item-connect-button-connection-timeout = Cysylltiad wedi dod i ben
+
+# Temporary text displayed in sidebar items representing remote runtimes after
+# successfully connecting to them. Temporary UI, do not localize.
+about-debugging-sidebar-item-connected-label = Wedi cysylltu
+
+# Text displayed in sidebar items for remote devices where a compatible browser (eg
+# Firefox) has not been detected yet. Typically, Android phones connected via USB with
+# USB debugging enabled, but where Firefox is not started.
+about-debugging-sidebar-runtime-item-waiting-for-browser = Aros am borwr...
+
+# Text displayed in sidebar items for remote devices that have been disconnected from the
+# computer.
+about-debugging-sidebar-runtime-item-unplugged = Wedi'i ddatgysylltu
+
+# Title for runtime sidebar items that are related to a specific device (USB, WiFi).
+about-debugging-sidebar-runtime-item-name =
+    .title = { $displayName } ({ $deviceName })
+# Title for runtime sidebar items where we cannot get device information (network
+# locations).
+about-debugging-sidebar-runtime-item-name-no-device =
+    .title = { $displayName }
+
+# Text to show in the footer of the sidebar that links to a help page
+# (currently: https://developer.mozilla.org/docs/Tools/about:debugging)
+about-debugging-sidebar-support = Cefnogaeth dadfygio
+
+# Text to show as the ALT attribute of a help icon that accompanies the help about
+# debugging link in the footer of the sidebar
+about-debugging-sidebar-support-icon =
+    .alt = Eicon Cymorth
+
+# Text displayed in a sidebar button to refresh the list of USB devices. Clicking on it
+# will attempt to update the list of devices displayed in the sidebar.
+about-debugging-refresh-usb-devices-button = Adnewyddu dyfeisiau
+
+# Setup Page strings
+
+# Title of the Setup page.
+about-debugging-setup-title = Gosod
+
+# Introduction text in the Setup page to explain how to configure remote debugging.
+about-debugging-setup-intro = Ffurfweddwch y dull cysylltu rydych chi eisiau dadfygio eich dyfais o bell gydag ef.
+
+# Explanatory text in the Setup page about what the 'This Firefox' page is for
+about-debugging-setup-this-firefox2 = Defnyddiwch { about-debugging-this-firefox-runtime-name }</a> i ddadfygio tabiau, estyniadau a gweithwyr gwasanaeth ar y fersiwn hon o { -brand-shorter-name }.
+
+# Title of the heading Connect section of the Setup page.
+about-debugging-setup-connect-heading = Cysylltu Dyfais
+
+# USB section of the Setup page
+about-debugging-setup-usb-title = USB
+
+# Explanatory text displayed in the Setup page when USB debugging is disabled
+about-debugging-setup-usb-disabled = Bydd galluogi hyn yn llwytho i lawr ac yn ychwanegu'r cydrannau dadfygio Android USB at { -brand-shorter-name }.
+
+# Text of the button displayed in the USB section of the setup page when USB debugging is disabled.
+# Clicking on it will download components needed to debug USB Devices remotely.
+about-debugging-setup-usb-enable-button = Galluogi Dyfeisiau USB
+
+# Text of the button displayed in the USB section of the setup page when USB debugging is enabled.
+about-debugging-setup-usb-disable-button = Analluogi Dyfeisiau USB
+
+# Text of the button displayed in the USB section of the setup page while USB debugging
+# components are downloaded and installed.
+about-debugging-setup-usb-updating-button = Diweddaru…
+
+# USB section of the Setup page (USB status)
+about-debugging-setup-usb-status-enabled = Galluogwyd
+about-debugging-setup-usb-status-disabled = Analluogwyd
+about-debugging-setup-usb-status-updating = Diweddaru…
+
+# USB section step by step guide
+about-debugging-setup-usb-step-enable-dev-menu2 = Galluogi dewislen datblygwyr ar eich dyfais Android.
+
+# USB section step by step guide
+about-debugging-setup-usb-step-enable-debug2 = Galluogi Dadfygio USB yn Newislen Datblygwr Android.
+
+# USB section step by step guide
+about-debugging-setup-usb-step-enable-debug-firefox2 = Galluogi Dadfygio USB yn Firefox ar y ddyfais Android.
+
+# USB section step by step guide
+about-debugging-setup-usb-step-plug-device = Cysylltu'r ddyfais Android i'ch cyfrifiadur.
+
+# Text shown in the USB section of the setup page with a link to troubleshoot connection errors.
+# The link goes to https://developer.mozilla.org/docs/Tools/Remote_Debugging/Debugging_over_USB
+about-debugging-setup-usb-troubleshoot = Anhawster cysylltu â'r ddyfais USB? <a>Datrys problemau</a>
+
+# Network section of the Setup page
+about-debugging-setup-network =
+    .title = Lleoliad Rhwydwaith
+
+# Text shown in the Network section of the setup page with a link to troubleshoot connection errors.
+# The link goes to https://developer.mozilla.org/en-US/docs/Tools/Remote_Debugging/Debugging_over_a_network
+about-debugging-setup-network-troubleshoot = Anawsterau cysylltu drwy leoliad rhwydwaith? <a>Datrys problemau</a>
+
+# Text of a button displayed after the network locations "Host" input.
+# Clicking on it will add the new network location to the list.
+about-debugging-network-locations-add-button = Ychwanegu
+
+# Text to display when there are no locations to show.
+about-debugging-network-locations-empty-text = Nid oes unrhyw leoliadau rhwydwaith wedi'u hychwanegu eto.
+
+# Text of the label for the text input that allows users to add new network locations in
+# the Connect page. A host is a hostname and a port separated by a colon, as suggested by
+# the input's placeholder "localhost:6080".
+about-debugging-network-locations-host-input-label = Gwesteiwr
+
+# Text of a button displayed next to existing network locations in the Connect page.
+# Clicking on it removes the network location from the list.
+about-debugging-network-locations-remove-button = Tynnu
+
+# Text used as error message if the format of the input value was invalid in the network locations form of the Setup page.
+# Variables:
+#   $host-value (string) - The input value submitted by the user in the network locations form
+about-debugging-network-location-form-invalid = Gwestai annilys  “{ $host-value }”.Y fformat disgwyliedig yw “hostname:portnumber”.
+
+# Text used as error message if the input value was already registered in the network locations form of the Setup page.
+# Variables:
+#   $host-value (string) - The input value submitted by the user in the network locations form
+about-debugging-network-location-form-duplicate = Mae'r gwestai “{ $host-value }” eisoes wedi ei gofrestru
+
+# Runtime Page strings
+
+# Below are the titles for the various categories of debug targets that can be found
+# on "runtime" pages of about:debugging.
+# Title of the temporary extensions category (only available for "This Firefox" runtime).
+about-debugging-runtime-temporary-extensions =
+    .name = Estyniadau Dros Dro
+# Title of the extensions category.
+about-debugging-runtime-extensions =
+    .name = Estyniadau
+# Title of the tabs category.
+about-debugging-runtime-tabs =
+    .name = Tabiau
+# Title of the service workers category.
+about-debugging-runtime-service-workers =
+    .name = Service Workers
+# Title of the shared workers category.
+about-debugging-runtime-shared-workers =
+    .name = Shared Workers
+# Title of the other workers category.
+about-debugging-runtime-other-workers =
+    .name = Other Workers
+# Title of the processes category.
+about-debugging-runtime-processes =
+    .name = Prosesau
+
+# Label of the button opening the performance profiler panel in runtime pages for remote
+# runtimes.
+about-debugging-runtime-profile-button2 = Perfformiad proffil
+
+# This string is displayed in the runtime page if the current configuration of the
+# target runtime is incompatible with service workers. "Learn more" points to MDN.
+# https://developer.mozilla.org/en-US/docs/Tools/about%3Adebugging#Service_workers_not_compatible
+about-debugging-runtime-service-workers-not-compatible = Nid yw ffurfweddiad eich porwr yn cydweddu â Service Workers. <a>Dysgu rhagor</a>
+
+# This string is displayed in the runtime page if the remote browser version is too old.
+# "Troubleshooting" link points to https://developer.mozilla.org/docs/Tools/about:debugging#Troubleshooting
+# { $runtimeVersion } is the version of the remote browser (for instance "67.0a1")
+# { $minVersion } is the minimum version that is compatible with the current Firefox instance (same format)
+about-debugging-browser-version-too-old = Mae gan y porwr cysylltiedig hen fersiwn ({ $runtimeVersion }). Y fersiwn lleiaf sy'n cael ei gynnal yw ({ $minVersion }). Mae hwn yn osodiad sydd dim yn cael ei gynnal a gall achosi i DevTools fethu. Diweddarwch y porwr cysylltiedig. <a>Datrys problemau</a>
+
+# Dedicated message for a backward compatibility issue that occurs when connecting:
+# from Fx 70+ to the old Firefox for Android (aka Fennec) which uses Fx 68.
+about-debugging-browser-version-too-old-fennec = Nid oes modd i'r fersiwn yma o Firefox ddadfygio Firefox ar gyfer Android (68). Rydym yn argymell gosod Firefox ar gyfer Android Nightly ar eich ffôn i'w brofi. <a> Rhagor o fanylion </a>
+
+# This string is displayed in the runtime page if the remote browser version is too recent.
+# "Troubleshooting" link points to https://developer.mozilla.org/docs/Tools/about:debugging#Troubleshooting
+# { $runtimeID } is the build ID of the remote browser (for instance "20181231", format is yyyyMMdd)
+# { $localID } is the build ID of the current Firefox instance (same format)
+# { $runtimeVersion } is the version of the remote browser (for instance "67.0a1")
+# { $localVersion } is the version of your current browser (same format)
+about-debugging-browser-version-too-recent = Mae'r porwr cysylltiedig yn fwy diweddar ( { $runtimeVersion }, buildID { $runtimeID }) na'ch { -brand-shorter-name } ({ $localVersion }, BuildID{ $localID }). Mae hwn yn osodiad heb gefnogaeth ac fe all beri i DevTools fethu. Diweddarwch Firefox. <a>Datrys Problemau</a>
+
+# Displayed for runtime info in runtime pages.
+# { $name } is brand name such as "Firefox Nightly"
+# { $version } is version such as "64.0a1"
+about-debugging-runtime-name = { $name } ({ $version })
+
+# Text of a button displayed in Runtime pages for remote runtimes.
+# Clicking on the button will close the connection to the runtime.
+about-debugging-runtime-disconnect-button = Datgysylltu
+
+# Text of the connection prompt button displayed in Runtime pages, when the preference
+# "devtools.debugger.prompt-connection" is false on the target runtime.
+about-debugging-connection-prompt-enable-button = Galluogi anogyn cysylltu
+
+# Text of the connection prompt button displayed in Runtime pages, when the preference
+# "devtools.debugger.prompt-connection" is true on the target runtime.
+about-debugging-connection-prompt-disable-button = Analluogi anogyn cysylltu
+
+# Title of a modal dialog displayed on remote runtime pages after clicking on the Profile Runtime button.
+about-debugging-profiler-dialog-title2 = Proffiliwr
+
+# Clicking on the header of a debug target category will expand or collapse the debug
+# target items in the category. This text is used as ’title’ attribute of the header,
+# to describe this feature.
+about-debugging-collapse-expand-debug-targets = Cau / ehangu
+
+# Debug Targets strings
+
+# Displayed in the categories of "runtime" pages that don't have any debug target to
+# show. Debug targets depend on the category (extensions, tabs, workers...).
+about-debugging-debug-target-list-empty = Dim byd eto.
+
+# Text of a button displayed next to debug targets of "runtime" pages. Clicking on this
+# button will open a DevTools toolbox that will allow inspecting the target.
+# A target can be an addon, a tab, a worker...
+about-debugging-debug-target-inspect-button = Archwilio
+
+# Text of a button displayed in the "This Firefox" page, in the Temporary Extension
+# section. Clicking on the button will open a file picker to load a temporary extension
+about-debugging-tmp-extension-install-button = Llwytho Ychwanegyn Dros Dro…
+
+# Text displayed when trying to install a temporary extension in the "This Firefox" page.
+about-debugging-tmp-extension-install-error = Digwyddodd gwall wrth osod ychwanegyn dros dro
+
+# Text of a button displayed for a temporary extension loaded in the "This Firefox" page.
+# Clicking on the button will reload the extension.
+about-debugging-tmp-extension-reload-button = Ail-lwytho
+
+# Text of a button displayed for a temporary extension loaded in the "This Firefox" page.
+# Clicking on the button will uninstall the extension and remove it from the page.
+about-debugging-tmp-extension-remove-button = Tynnu
+
+# Message displayed in the file picker that opens to select a temporary extension to load
+# (triggered by the button using "about-debugging-tmp-extension-install-button")
+# manifest.json .xpi and .zip should not be localized.
+# Note: this message is only displayed in Windows and Linux platforms.
+about-debugging-tmp-extension-install-message = Dewis ffeil maniffest.json neu .xpi /.zip
+
+# This string is displayed as a message about the add-on having a temporaryID.
+about-debugging-tmp-extension-temporary-id = Mae gan y WebExtension ID dros dro. <a>Dysgu rhagor</a>
+
+# Text displayed for extensions in "runtime" pages, before displaying a link the extension's
+# manifest URL.
+about-debugging-extension-manifest-url =
+    .label = URL Maniffest
+
+# Text displayed for extensions in "runtime" pages, before displaying the extension's uuid.
+# UUIDs look like b293e463-481e-5148-a487-5aaf7a130429
+about-debugging-extension-uuid =
+    .label = UUID mewnol
+
+# Text displayed for extensions (temporary extensions only) in "runtime" pages, before
+# displaying the location of the temporary extension.
+about-debugging-extension-location =
+    .label = Lleoliad
+
+# Text displayed for extensions in "runtime" pages, before displaying the extension's ID.
+# For instance "geckoprofiler@mozilla.com" or "{ed26ddcb-5611-4512-a89a-51b8db81cfb2}".
+about-debugging-extension-id =
+    .label = Enw'r Estyniadau
+
+# This string is displayed as a label of the button that pushes a test payload
+# to a service worker.
+# Note this relates to the "Push" API, which is normally not localized so it is
+# probably better to not localize it.
+about-debugging-worker-action-push2 = Gwthio
+    .disabledTitle = Mae Gweithiwr Gwasanaeth gwthio wedi ei analluogi ar hyn o bryd ar gyfer amlbroses { -brand-shorter-name }
+
+# This string is displayed as a label of the button that starts a service worker.
+about-debugging-worker-action-start2 = Cychwyn
+    .disabledTitle = Mae Gweithiwr Gwasanaeth gwthio wedi ei analluogi ar hyn o bryd ar gyfer amlbroses { -brand-shorter-name }
+
+# This string is displayed as a label of the button that unregisters a service worker.
+about-debugging-worker-action-unregister = Dadgofrestru
+
+# Displayed for service workers in runtime pages that listen to Fetch events.
+about-debugging-worker-fetch-listening =
+    .label = Estyn
+    .value = Gwrando am ddigwyddiadau estyn
+
+# Displayed for service workers in runtime pages that do not listen to Fetch events.
+about-debugging-worker-fetch-not-listening =
+    .label = Estyn
+    .value = Ddim yn gwrando ar ddigwyddiadau estyn
+
+# Displayed for service workers in runtime pages that are currently running (service
+# worker instance is active).
+about-debugging-worker-status-running = Rhedeg
+
+# Displayed for service workers in runtime pages that are registered but stopped.
+about-debugging-worker-status-stopped = Wedi Atal
+
+# Displayed for service workers in runtime pages that are registering.
+about-debugging-worker-status-registering = Cofrestru
+
+# Displayed for service workers in runtime pages, to label the scope of a worker
+about-debugging-worker-scope =
+    .label = Cwmpas
+
+# Displayed for service workers in runtime pages, to label the push service endpoint (url)
+# of a worker
+about-debugging-worker-push-service =
+    .label = Gwasanaeth Gwthio
+
+# Displayed as title of the inspect button when service worker debugging is disabled.
+about-debugging-worker-inspect-action-disabled =
+    .title = Mae Gweithiwr Gwasanaeth gwthio wedi ei analluogi ar hyn o bryd ar gyfer amlbroses { -brand-shorter-name }
+
+# Displayed as title of the inspect button for zombie tabs (e.g. tabs loaded via a session restore).
+about-debugging-zombie-tab-inspect-action-disabled =
+    .title = Nid yw'r tab wedi'i lwytho'n llawn ac nid oes modd ei archwilio
+
+# Displayed as name for the Main Process debug target in the Processes category. Only for
+# remote runtimes, if `devtools.aboutdebugging.process-debugging` is true.
+about-debugging-main-process-name = Prif Broses
+
+# Displayed as description for the Main Process debug target in the Processes category.
+# Only for remote browsers, if `devtools.aboutdebugging.process-debugging` is true.
+about-debugging-main-process-description2 = Prif Broses y porwr targed
+
+# Displayed instead of the Main Process debug target when the preference
+# `devtools.browsertoolbox.fission` is true.
+about-debugging-multiprocess-toolbox-name = Blwch Offer Amlbroses
+
+# Description for the Multiprocess Toolbox target.
+about-debugging-multiprocess-toolbox-description = Prif Broses a Phrosesau Cynnwys ar gyfer y porwr targed
+
+# Alt text used for the close icon of message component (warnings, errors and notifications).
+about-debugging-message-close-icon =
+    .alt = Cau neges
+
+# Label text used for the error details of message component.
+about-debugging-message-details-label-error = Manylion gwall
+
+# Label text used for the warning details of message component.
+about-debugging-message-details-label-warning = Manylion rhybudd
+
+# Label text used for default state of details of message component.
+about-debugging-message-details-label = Manylion
diff --git a/l10n-cy/devtools/client/accessibility.ftl b/l10n-cy/devtools/client/accessibility.ftl
new file mode 100644
index 0000000000..682cd9b160
--- /dev/null
+++ b/l10n-cy/devtools/client/accessibility.ftl
@@ -0,0 +1,79 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used inside the Accessibility panel.
+
+accessibility-learn-more = Dysgu rhagor
+
+accessibility-text-label-header = Labeli ac Enwau Testun
+
+accessibility-keyboard-header = Bysellfwrdd
+
+## Text entries that are used as text alternative for icons that depict accessibility isses.
+
+accessibility-warning =
+    .alt = Rhybudd
+
+accessibility-fail =
+    .alt = Gwall
+
+accessibility-best-practices =
+    .alt = Ymarfer Gorau
+
+## Text entries for a paragraph used in the accessibility panel sidebar's checks section
+## that describe that currently selected accessible object has an accessibility issue
+## with its text label or accessible name.
+
+accessibility-text-label-issue-area = Defnyddiwch briodoledd <code>alt</code> i labelu elfennau <div>ardal</div> sydd â phriodoledd <span>href</span>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-dialog = Rhais labelu deialogau. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-document-title = Rhaid i ddogfennau feddu ar <code>deitl</code>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-embed = Rhaid labelu cynnwys wedi'i fewnblannu. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-figure = Dylid labelu nodau â chapsiynau dewisol. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-fieldset = Rhaid labelu elfennau <code>fielset</code>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-fieldset-legend2 = Defnyddiwch elfen <code>legend</code> i labelu <span>fieldset</span>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-form = Rhaid labelu elfennau ffurflen. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-form-visible = Dylai fod gan elfennau ffurflenni label testun gweladwy. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-frame = Rhaid labelu elfennau <code>frame</code>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-glyph = Defnyddiwch briodoledd <code>alt</code> i labelu elfennau <span>mglyph</span>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-heading = Rhaid labelu'r penawdau. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-heading-content = Dylai penawdau gynnwys testun gweladwy. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-iframe = Defnyddiwch briodoledd <code>title</code> i ddisgrifio cynnwys <span>iframe</span>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-image = Rhaid labelu cynnwys gyda delweddau. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-interactive = Rhaid labelu elfennau rhyngweithiol. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-optgroup-label2 = Defnyddiwch briodoledd <code>label</code> i labelu <span>optgroup</span>. <a>Dysgu rhagor</a>
+
+accessibility-text-label-issue-toolbar = Rhaid labelu bariau offer pan fydd mwy nag un bar offer. <a>Dysgu rhagor</a>
+
+## Text entries for a paragraph used in the accessibility panel sidebar's checks section
+## that describe that currently selected accessible object has a keyboard accessibility
+## issue.
+
+accessibility-keyboard-issue-semantics = Dylai elfennau ffocwsadwy fod â semanteg ryngweithiol. <a>Dysgu rhagor</a>
+
+accessibility-keyboard-issue-tabindex = Ceisiwch osgoi defnyddio priodoledd <code>tabindex</code> sy'n fwy na sero. <a>Dysgu rhagor</a>
+
+accessibility-keyboard-issue-action = Rhaid gallu actifadu elfennau rhyngweithiol gan ddefnyddio bysellfwrdd. <a>Dysgu rhagor</a>
+
+accessibility-keyboard-issue-focusable = Rhaid i elfennau rhyngweithiol fod yn ffocwsadwy. <a>Dysgu rhagor</a>
+
+accessibility-keyboard-issue-focus-visible = Efallai bod elfen ffocwsadwy yn brin o steilio ffocws. <a>Dysgu rhagor</a>
+
+accessibility-keyboard-issue-mouse-only = Dylai elfennau clicadwy fod â semanteg ryngweithiol. <a>Dysgu rhagor</a>
diff --git a/l10n-cy/devtools/client/accessibility.properties b/l10n-cy/devtools/client/accessibility.properties
new file mode 100644
index 0000000000..e38cca7550
--- /dev/null
+++ b/l10n-cy/devtools/client/accessibility.properties
@@ -0,0 +1,310 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Accessibility panel
+# which is available from the Web Developer sub-menu -> 'Accessibility'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (accessibility.role): A title text used for Accessibility
+# tree header column that represents accessible element role.
+accessibility.role=Rôl
+
+# LOCALIZATION NOTE (accessibility.name): A title text used for Accessibility
+# tree header column that represents accessible element name.
+accessibility.name=Enw
+
+# LOCALIZATION NOTE (accessibility.logo): A title text used for Accessibility
+# logo used on the accessibility panel landing page.
+accessibility.logo=Logo Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.properties): A title text used for header
+# for Accessibility details sidebar.
+accessibility.properties=Priodoleddau…
+
+# LOCALIZATION NOTE (accessibility.treeName): A title text used for
+# Accessibility tree (that represents accessible element name) container.
+accessibility.treeName=Coeden Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.accessible.notAvailable): A title text
+# displayed when accessible sidebar panel does not have an accessible object to
+# display.
+accessibility.accessible.notAvailable=Nid yw'r Wybodaeth Hygyrchedd ar Gael
+
+# LOCALIZATION NOTE (accessibility.enable): A title text for Enable
+# accessibility button used to enable accessibility service.
+accessibility.enable=Agor y Nodweddion Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.enabling): A title text for Enable
+# accessibility button used when accessibility service is being enabled.
+accessibility.enabling=Yn agor y nodweddion hygyrchedd…
+
+# LOCALIZATION NOTE (accessibility.disable): A title text for Disable
+# accessibility button used to disable accessibility service.
+accessibility.disable=Cau'r Nodweddion Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.disabling): A title text for Disable
+# accessibility button used when accessibility service is being
+# disabled.
+accessibility.disabling=Yn cau'r nodweddion hygyrchedd…
+
+# LOCALIZATION NOTE (accessibility.pick): A title text for Picker button
+# button used to pick accessible objects from the page.
+accessibility.pick=Dewis gwrthrych hygyrchedd o'r dudalen
+
+# LOCALIZATION NOTE (accessibility.disable.disabledTitle): A title text used for
+# a tooltip for Disable accessibility button when accessibility service can not
+# be disabled. It is the case when a user is using a 3rd party accessibility
+# tool such as screen reader.
+accessibility.disable.disabledTitle=Nid oes modd diffodd y gwasanaeth hygyrchedd. Mae'n cael ei ddefnyddio y tu allan i Offer Datblygwyr.
+
+# LOCALIZATION NOTE (accessibility.disable.enabledTitle): A title text used for
+# a tooltip for Disable accessibility button when accessibility service can be
+# disabled.
+accessibility.disable.enabledTitle=Bydd y gwasanaeth Hygyrchedd yn cael ei gau ar gyfer pob tab a ffenestr.
+
+# LOCALIZATION NOTE (accessibility.enable.disabledTitle): A title text used for
+# a tooltip for Enabled accessibility button when accessibility service can not
+# be enabled.
+accessibility.enable.disabledTitle=Nid oes modd agor y gwasanaeth hygyrchedd. Mae'n cael ei agor drwy ddewis preifatrwydd gwasanaethau hygyrchedd.
+
+# LOCALIZATION NOTE (accessibility.enable.enabledTitle): A title text used for
+# a tooltip for Enabled accessibility button when accessibility service can be
+# enabled.
+accessibility.enable.enabledTitle=Bydd gwasanaeth hygyrchedd yn cael ei agor ar gyfer pob tab a ffenestr.
+
+# LOCALIZATION NOTE (accessibility.learnMore): A text that is used as is or as textual
+# description in places that link to accessibility inspector documentation.
+accessibility.learnMore=Dysgu rhagor
+
+# LOCALIZATION NOTE (accessibility.description.general.p1): A title text for the first
+# paragraph, used when accessibility service description is provided before accessibility
+# inspector is enabled. %S in the content will be replaced by a link at run time
+# with the accessibility.learnMore string.
+accessibility.description.general.p1=Mae'r arolygydd hygyrchedd yn gadael i chi archwilio'r goeden hygyrchedd y dudalen gyfredol, sy'n cael ei ddefnyddio gan ddarllenwyr sgrin a thechnolegau cymorth eraill . %S
+
+# LOCALIZATION NOTE (accessibility.description.general.p2): A title text for the second
+# paragraph, used when accessibility service description is provided before accessibility
+# inspector is enabled.
+accessibility.description.general.p2=Gall nodweddion hygyrchedd effeithio ar berfformiad paneli eraill yr offer datblygwr a dylai gael ei gau pan nad yw'n cael ei ddefnyddio.
+
+# LOCALIZATION NOTE (accessibility.tree.menu.printToJSON): A title text used when a
+# context menu item for printing an accessible tree to JSON is rendered after triggering a
+# context menu for an accessible tree row.
+accessibility.tree.menu.printToJSON=Argraffu i JSON
+
+# LOCALIZATION NOTE (accessibility.checks): A title text used for header for checks
+# section in Accessibility details sidebar.
+accessibility.checks=Gwiriadau
+
+# LOCALIZATION NOTE (accessibility.checks.empty2): A title text used for indicating that
+# accessibility checks for a node yielded no results and another node should be
+# selected.
+accessibility.checks.empty2=Dim gwiriadau ar gyfer y nod hwn.
+
+# LOCALIZATION NOTE (accessibility.contrast.header): A title text used for header for
+# checks related to color and contrast.
+accessibility.contrast.header=Lliw a Chyferbyniad
+
+# LOCALIZATION NOTE (accessibility.contrast.error): A title text for the color
+# contrast ratio, used when the tool is unable to calculate the contrast ratio value.
+accessibility.contrast.error=Methu cyfrifo
+
+# LOCALIZATION NOTE (accessibility.contrast.large.text): A title text for the color
+# contrast ratio label indicating that the color contrast criteria used is if for large
+# text. This is lower case because it's used as a label for a tree item in accessibility
+# tree.
+accessibility.contrast.large.text=testun mawr
+
+# LOCALIZATION NOTE (accessibility.contrast.large.title): A title text for the tooltip
+# used for the large text label (see accessibility.contrast.large.text).
+accessibility.contrast.large.title=Mae'r testun yn 14 pwynt ac yn drwm neu'n fwy, neu 18 pwynt neu fwy.
+
+# LOCALIZATION NOTE (accessibility.contrast.annotation.AA): A title text for the paragraph
+# describing that the given colour contrast satisfies AA standard from Web Content
+# Accessibility Guidelines. %S in the content will be replaced by a link at run time
+# with the accessibility.learnMore string.
+accessibility.contrast.annotation.AA=Yn cyd-fynd â safonau AAA WCAG ar gyfer testun hygyrch. %S
+
+# LOCALIZATION NOTE (accessibility.contrast.annotation.AAA): A title text for the
+# paragraph describing that the given colour contrast satisfies AAA standard from Web
+# Content Accessibility Guidelines. %S in the content will be replaced by a link at run
+# time with the accessibility.learnMore string.
+accessibility.contrast.annotation.AAA=Yn cyd-fynd â safonau AAA WCAG ar gyfer testun hygyrch. %S
+
+# LOCALIZATION NOTE (accessibility.contrast.annotation.FAIL): A title text for the
+# paragraph describing that the given colour contrast fails to meet the minimum level from
+# Web Content Accessibility Guidelines. %S in the content will be replaced by a link at
+# run time with the accessibility.learnMore string.
+accessibility.contrast.annotation.FAIL=Nid yw'n bodloni safonau WCAG ar gyfer testun hygyrch. %S
+
+# LOCALIZATION NOTE (accessibility.contrast.annotation.transparent.error): A title text for the
+# paragraph suggesting a fix for error in color contrast calculation for text nodes with zero alpha.
+accessibility.contrast.annotation.transparent.error=Dewiswch liw nad yw'n dryloyw.
+
+# LOCALIZATION NOTE (accessibility.badges): A title text for the group of badges
+# that are rendered for each accessible row within the accessibility tree when
+# one or more accessibility checks fail.
+accessibility.badges=Gwiriadau hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.filter.none): A title text for the filter
+# that is rendered within the accessibility panel toolbar for a menu item that
+# resets all filtering in tree, and for the simulation menu item that resets
+# applied color matrices to the default matrix.
+accessibility.filter.none=Dim
+
+# LOCALIZATION NOTE (accessibility.filter.all2): A title text for the filter
+# that is rendered within the accessibility panel toolbar for a menu item that
+# filters the tree based on all accessibility failures within it.
+accessibility.filter.all2=Pob Mater
+
+# LOCALIZATION NOTE (accessibility.filter.contrast): A title text for the filter
+# that is rendered within the accessibility panel toolbar for a menu item that
+# filters the tree based on contrast accessibility failures within it.
+accessibility.filter.contrast=Cyferbyniad
+
+# LOCALIZATION NOTE (accessibility.filter.textLabel): A title text for the filter
+# that is rendered within the accessibility panel toolbar for a menu item that
+# filters the tree based on text label and name accessibility failures within it.
+accessibility.filter.textLabel=Labeli Testun
+
+# LOCALIZATION NOTE (accessibility.filter.keyboard): A title text for the filter
+# that is rendered within the accessibility panel toolbar for a menu item that
+# filters the tree based on keyboard accessibility failures within it.
+accessibility.filter.keyboard=Bysellfwrdd
+
+# LOCALIZATION NOTE (accessibility.badge.contrast): A title text for the badge
+# that is rendered within the accessible row in the accessibility tree for a
+# given accessible object that does not satisfy the WCAG guideline for colour
+# contrast.
+accessibility.badge.contrast=cyferbyniad
+
+# LOCALIZATION NOTE (accessibility.badge.contrast.warning): A label for the
+# badge and attached warning icon that is rendered within the accessible row in
+# the accessibility tree for a given accessible object that does not satisfy the
+# WCAG guideline for colour contrast.
+accessibility.badge.contrast.warning=rhybudd cyferbyniad
+
+# LOCALIZATION NOTE (accessibility.badge.keyboard): A title text for the
+# badge that is rendered within the accessible row in the accessibility tree for
+# a given accessible object that does not satisfy the WCAG guideline for
+# keyboard accessibility.
+accessibility.badge.keyboard=bysellfwrdd
+
+# LOCALIZATION NOTE (accessibility.badge.textLabel): A title text for the
+# badge that is rendered within the accessible row in the accessibility tree for
+# a given accessible object that does not satisfy the WCAG guideline for text
+# alternative.
+accessibility.badge.textLabel=label testun
+
+# LOCALIZATION NOTE (accessibility.badge.contrast.tooltip): A title text for the
+# badge tooltip that is rendered on mouse hover over the badge in the accessible
+# row in the accessibility tree for a given accessible object that does not
+# satisfy the WCAG guideline for colour contrast.
+accessibility.badge.contrast.tooltip=Nid yw'n bodloni safonau WCAG ar gyfer testun hygyrch.
+
+# LOCALIZATION NOTE (accessibility.badge.keyboard.tooltip): A title text
+# for the badge tooltip that is rendered on mouse hover over the badge in the
+# accessible row in the accessibility tree for a given accessible object that
+# does not satisfy the WCAG guideline for keyboard accessibility.
+accessibility.badge.keyboard.tooltip=Nid yw'n bodloni safonau WCAG ar gyfer testun hygyrch.
+
+# LOCALIZATION NOTE (accessibility.badge.textLabel.tooltip): A title text
+# for the badge tooltip that is rendered on mouse hover over the badge in the
+# accessible row in the accessibility tree for a given accessible object that
+# does not satisfy the WCAG guideline for text alternative.
+accessibility.badge.textLabel.tooltip=Nid yw'n bodloni safonau WCAG am destun hygyrch.
+
+# LOCALIZATION NOTE (accessibility.tree.filters): A title text for the toolbar
+# within the main accessibility panel that contains a list of filters to be for
+# accessibility audit.
+accessibility.tree.filters=Gwirio am anawsterau:
+
+# LOCALIZATION NOTE (accessibility.tree.filters.prefs): A title text for the
+# preferences button tooltip that contains preferences for accessibility audit.
+accessibility.tree.filters.prefs=Ffurfweddu dewisiadau
+
+# LOCALIZATION NOTE (accessibility.progress.initializing): A title text for the
+# accessibility panel overlay shown when accessibility audit is starting up.
+accessibility.progress.initializing=Cychwyn…
+
+# LOCALIZATION NOTE (accessibility.progress.initializing): A title text for the
+# accessibility panel overlay shown when accessibility audit is running showing
+# the number of nodes being audited. Semi-colon list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+accessibility.progress.progressbar=Gwirio #1 nod;Gwirio #1 nod;Gwirio #1 nod;Gwirio #1 nod;Gwirio #1 nod;Gwirio #1 nod
+
+# LOCALIZATION NOTE (accessibility.progress.finishing): A title text for the
+# accessibility panel overlay shown when accessibility audit is finishing up.
+accessibility.progress.finishing=Cwblhau…
+
+# LOCALIZATION NOTE (accessibility.beta): A title text for the features in the
+# accessibility panel that are currently in beta.
+accessibility.beta=beta
+
+# LOCALIZATION NOTE (accessibility.pref.scroll.into.view.title): A title
+# text for the tooltip for the checkbox pref in the accessibility panel that
+# sets node auto scroll.
+accessibility.pref.scroll.into.view.title=Sgroliwch y nod a ddewiswyd yn awtomatig i'r golwg
+
+# LOCALIZATION NOTE (accessibility.pref.scroll.into.view.label): A title
+# text for the checkbox pref in the accessibility panel that sets node auto
+# scroll.
+accessibility.pref.scroll.into.view.label=Sgroliwch i'r golwg
+
+# LOCALIZATION NOTE (accessibility.documentation.label): This is the label for
+# the Documentation menu item.
+accessibility.documentation.label=Dogfennaeth…
+
+# LOCALIZATION NOTE (accessibility.simulation): A title text for the toolbar
+# within the main accessibility panel that contains a list of simulations for
+# vision deficiencies.
+accessibility.simulation=Efelychu:
+
+# LOCALIZATION NOTE (accessibility.simulation.deuteranomaly): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the deuteranomaly simulation option.
+accessibility.simulation.deuteranomaly=Deuteranomaledd (gwyrdd isel)
+
+# LOCALIZATION NOTE (accessibility.simulation.protanomaly): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the protanomaly simulation option.
+accessibility.simulation.protanomaly=Protanomaledd (coch isel)
+
+# LOCALIZATION NOTE (accessibility.simulation.protanopia): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the protanopia simulation option.
+accessibility.simulation.protanopia=Protanopia (dim coch)
+
+# LOCALIZATION NOTE (accessibility.simulation.deuteranopia): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the deuteranopia simulation option.
+accessibility.simulation.deuteranopia=Deuteranopia (dim gwyrdd)
+
+# LOCALIZATION NOTE (accessibility.simulation.tritanopia): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the tritanopia simulation option.
+accessibility.simulation.tritanopia=Tritanopia (dim glas)
+
+# LOCALIZATION NOTE (accessibility.simulation.tritanomaly): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the tritanomaly simulation option.
+accessibility.simulation.tritanomaly=Tritanomaledd (glas isel)
+
+# LOCALIZATION NOTE (accessibility.simulation.contrastLoss): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the contrast loss simulation option.
+# It is also shown in the simulation menu button in the accessibility panel and represent the
+# contrast loss simulation option currently selected.
+accessibility.simulation.contrastLoss=Colli cyferbyniad
+
+# LOCALIZATION NOTE (accessibility.simulation.achromatopsia): This label is shown
+# in the "Simulate" menu in the accessibility panel and represent the achromatopsia simulation option.
+accessibility.simulation.achromatopsia=Acromatopsia (dim lliw)
+
+# LOCALIZATION NOTE (accessibility.toolbar.displayTabbingOrder.label): A title text for a checkbox label
+# in the accessibility panel toolbar that turns on/off the overlay of focusable elements in their
+# tabbing order.
+accessibility.toolbar.displayTabbingOrder.label=Dangos Trefn Tabio
+
+# LOCALIZATION NOTE (accessibility.toolbar.displayTabbingOrder.tooltip): A title text for a checkbox
+# tooltip in the accessibility panel toolbar that turns on/off the overlay of focusable elements in
+# their tabbing order.
+accessibility.toolbar.displayTabbingOrder.tooltip=Dangos trefn tabio elfennau a'u mynegai tabio.
diff --git a/l10n-cy/devtools/client/animationinspector.properties b/l10n-cy/devtools/client/animationinspector.properties
new file mode 100644
index 0000000000..05cb896a54
--- /dev/null
+++ b/l10n-cy/devtools/client/animationinspector.properties
@@ -0,0 +1,183 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Animation inspector
+# which is available as a sidebar panel in the Inspector.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (panel.noAnimation):
+# This is the label shown in the panel when there are no displayable animations.
+# (e.g. In case of user selected a non-element node or a node that is not animated).
+panel.noAnimation=Nid oes animeiddiadau wedi eu canfod ar gyfer yr elfen gyfredol.\nDewiswch elfen arall o'r dudalen.
+
+# LOCALIZATION NOTE (player.animationDurationLabel):
+# This string is displayed in each animation player widget. It is the label
+# displayed before the animation duration.
+player.animationDurationLabel=Hyd:
+
+# LOCALIZATION NOTE (player.infiniteDurationText):
+# This string is displayed in a tooltip on animation player widget, in case the
+# duration of the animation is infinite.
+player.infiniteDurationText=∞
+
+# LOCALIZATION NOTE (player.animationDelayLabel):
+# This string is displayed in each animation player widget. It is the label
+# displayed before the animation delay.
+player.animationDelayLabel=Oedi:
+
+# LOCALIZATION NOTE (player.animationEndDelayLabel):
+# This string is displayed in each animation player widget. It is the label
+# displayed before the animation endDelay.
+player.animationEndDelayLabel=Oedi diwedd:
+
+# LOCALIZATION NOTE (player.animationRateLabel):
+# This string is displayed in each animation player widget. It is the label
+# displayed before the animation playback rate.
+player.animationRateLabel=Cyfradd chwarae:
+
+# LOCALIZATION NOTE (player.animationIterationCountLabel):
+# This string is displayed in each animation player widget. It is the label
+# displayed before the number of times the animation is set to repeat.
+player.animationIterationCountLabel=Ail-adrodd:
+
+# LOCALIZATION NOTE (player.infiniteIterationCount):
+# In case the animation repeats infinitely, this string is displayed next to the
+# player.animationIterationCountLabel string, instead of a number.
+player.infiniteIterationCount=&#8734;
+
+# LOCALIZATION NOTE (player.infiniteIterationCountText):
+# See player.infiniteIterationCount for a description of what this is.
+# Unlike player.infiniteIterationCount, this string isn't used in HTML, but in
+# a tooltip.
+player.infiniteIterationCountText=∞
+
+# LOCALIZATION NOTE (player.animationIterationStartLabel2):
+# This string is displayed in a tooltip that appears when hovering over
+# animations in the timeline. It is the label displayed before the animation
+# iterationStart value.
+# %1$S will be replaced by the original iteration start value
+# %2$S will be replaced by the actual time of iteration start without time unit
+# e.g.
+# If iterationStart of animation is 0.5 and duration is 1 sec, the string will be
+# "Iteration start: 0.5 (0.5s)"
+player.animationIterationStartLabel2=Cychwyn iteriad: %1$S (%2$Ss)
+
+# LOCALIZATION NOTE (player.animationOverallEasingLabel):
+# This string is displayed in a tooltip that appears when hovering over
+# animations in the timeline. It is the label displayed before the easing
+# that applies to a whole iteration of an animation as opposed to the
+# easing that applies between animation keyframes.
+player.animationOverallEasingLabel=Lleddfu Cyffredinol:
+
+# LOCALIZATION NOTE (player.animationTimingFunctionLabel):
+# This string is displayed in a tooltip that appears when hovering over
+# animations in the timeline. It is the label displayed before the
+# animation-timing-function for CSS Animations.
+player.animationTimingFunctionLabel=Swyddogaethau amseru animeiddio:
+
+# LOCALIZATION NOTE (player.animationFillLabel):
+# This string is displayed in a tooltip that appears when hovering over
+# animations in the timeline. It is the label displayed before the animation
+# fill mode value.
+player.animationFillLabel=Llanw:
+
+# LOCALIZATION NOTE (player.animationDirectionLabel):
+# This string is displayed in a tooltip that appears when hovering over
+# animations in the timeline. It is the label displayed before the animation
+# direction value.
+player.animationDirectionLabel=Cyfeiriad:
+
+# LOCALIZATION NOTE (player.timeLabel):
+# This string is displayed in each animation player widget, to indicate either
+# how long (in seconds) the animation lasts, or what is the animation's current
+# time (in seconds too);
+player.timeLabel=%Ss
+
+# LOCALIZATION NOTE (player.infiniteDurationText):
+# This string is displayed in animation player widget, in case the duration of the
+# animation is infinite.
+player.infiniteTimeLabel=∞
+
+# LOCALIZATION NOTE (player.playbackRateLabel):
+# This string is displayed in each animation player widget, as the label of
+# drop-down list items that can be used to change the rate at which the
+# animation runs (1× being the default, 2× being twice as fast).
+player.playbackRateLabel=%S×
+
+# LOCALIZATION NOTE (player.runningOnCompositorTooltip):
+# This string is displayed as a tooltip for the icon that indicates that the
+# animation is running on the compositor thread.
+player.runningOnCompositorTooltip=Mae'r animeiddiad yn rhedeg ar linyn cysodydd
+
+# LOCALIZATION NOTE (player.allPropertiesOnCompositorTooltip):
+# This string is displayed as a tooltip for the icon that indicates that
+# all of animation is running on the compositor thread.
+player.allPropertiesOnCompositorTooltip=Mae holl briodweddau animeiddio wedi eu hoptimeiddio
+
+# LOCALIZATION NOTE (player.somePropertiesOnCompositorTooltip):
+# This string is displayed as a tooltip for the icon that indicates that
+# all of animation is not running on the compositor thread.
+player.somePropertiesOnCompositorTooltip=Mae rhai priodweddau animeiddi wedi eu hoptimeiddio
+
+# LOCALIZATION NOTE (timeline.pausedButtonTooltip):
+# This string is displayed in the timeline toolbar, as the tooltip of the
+# pause/resume button that can be used to pause or resume the animations
+timeline.pausedButtonTooltip=Ailgychwyn yr animeiddio
+
+# LOCALIZATION NOTE (timeline.resumedButtonTooltip):
+# This string is displayed in the timeline toolbar, as the tooltip of the
+# pause/resume button that can be used to pause or resume the animations
+timeline.resumedButtonTooltip=Oedi'r animeiddio
+
+# LOCALIZATION NOTE (timeline.rewindButtonTooltip):
+# This string is displayed in the timeline toolbar, as the tooltip of the
+# rewind button that can be used to rewind the animations
+timeline.rewindButtonTooltip=Mynd â'r animeiddio yn ôl
+
+# LOCALIZATION NOTE (timeline.timeGraduationLabel):
+# This string is displayed at the top of the animation panel, next to each time
+# graduation, to indicate what duration (in milliseconds) this graduation
+# corresponds to.
+timeline.timeGraduationLabel=%Sms
+
+# LOCALIZATION NOTE (timeline.cssanimation.nameLabel):
+# This string is displayed in a tooltip of the animation panel that is shown
+# when hovering over the name of a CSS Animation in the timeline UI.
+# %S will be replaced by the name of the animation at run-time.
+timeline.cssanimation.nameLabel=%S - Animeiddio CSS
+
+# LOCALIZATION NOTE (timeline.csstransition.nameLabel):
+# This string is displayed in a tooltip of the animation panel that is shown
+# when hovering over the name of a CSS Transition in the timeline UI.
+# %S will be replaced by the name of the transition at run-time.
+timeline.csstransition.nameLabel=%S - Trawsnewid CSS
+
+# LOCALIZATION NOTE (timeline.scriptanimation.nameLabel):
+# This string is displayed in a tooltip of the animation panel that is shown
+# when hovering over the name of a script-generated animation in the timeline UI.
+# %S will be replaced by the name of the animation at run-time.
+timeline.scriptanimation.nameLabel=%S - Animeiddio Sgript
+
+# LOCALIZATION NOTE (timeline.scriptanimation.unnamedLabel):
+# This string is displayed in a tooltip of the animation panel that is shown
+# when hovering over an unnamed script-generated animation in the timeline UI.
+timeline.scriptanimation.unnamedLabel=Animeiddio Sgript
+
+# LOCALIZATION NOTE (timeline.unknown.nameLabel):
+# This string is displayed in a tooltip of the animation panel that is shown
+# when hovering over the name of an unknown animation type in the timeline UI.
+# This can happen if devtools couldn't figure out the type of the animation.
+# %S will be replaced by the name of the transition at run-time.
+timeline.unknown.nameLabel=%S
+
+# LOCALIZATION NOTE (detail.propertiesHeader.percentage):
+# This string is displayed on header label in .animated-properties-header.
+# %S represents the value in percentage with two decimal points, localized.
+# there are two "%" after %S to escape and display "%"
+detail.propertiesHeader.percentage=%S%%
+
diff --git a/l10n-cy/devtools/client/application.ftl b/l10n-cy/devtools/client/application.ftl
new file mode 100644
index 0000000000..60302d9632
--- /dev/null
+++ b/l10n-cy/devtools/client/application.ftl
@@ -0,0 +1,187 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used inside the Application panel which is available
+### by setting the preference `devtools-application-enabled` to true.
+
+
+### The correct localization of this file might be to keep it in English, or another
+### language commonly spoken among web developers. You want to make that choice consistent
+### across the developer tools. A good criteria is the language in which you'd find the
+### best documentation on web development on the web.
+
+# Header for the list of Service Workers displayed in the application panel for the current page.
+serviceworker-list-header = Gweithwyr Gwasanaeth
+
+# Text displayed next to the list of Service Workers to encourage users to check out
+# about:debugging to see all registered Service Workers.
+serviceworker-list-aboutdebugging = Agor <a>about:debugging</a> ar gyfer Gweithwyr Gwasanaeth o barthau eraill
+
+# Text for the button to unregister a Service Worker. Displayed for active Service Workers.
+serviceworker-worker-unregister = Dadgofrestru
+
+# Text for the debug link displayed for an already started Service Worker. Clicking on the
+# link opens a new devtools toolbox for this service worker. The title attribute is only
+# displayed when the link is disabled.
+serviceworker-worker-debug = Dadfygio
+    .title = Dim ond gweithwyr gwasanaeth sy'n rhedeg y mae modd eu dadfygio
+
+# Text for the debug link displayed for an already started Service Worker, when we
+# are in multi e10s mode, which effectively disables this link.
+serviceworker-worker-debug-forbidden = Dadfygio
+    .title = Gall ddadfygio gweithwyr gwasanaeth os yw e10s lluosog wedi eu hanalluogi.
+
+# Text for the start link displayed for a registered but not running Service Worker.
+# Clicking on the link will attempt to start the service worker.
+serviceworker-worker-start2 = Cychwyn
+    .title = Gall gychwyn gweithwyr gwasanaeth os yw e10s lluosog wedi eu hanalluogi.
+
+# Alt text for the image icon displayed inside a debug link for a service worker.
+serviceworker-worker-inspect-icon =
+    .alt = Archwilio
+
+# Text for the start link displayed for a registered but not running Service Worker.
+# Clicking on the link will attempt to start the service worker.
+serviceworker-worker-start3 = Cychwyn
+
+# Text displayed for the updated time of the service worker. The <time> element will
+# display the last update time of the service worker script.
+serviceworker-worker-updated = Diweddarwyd <time>{ DATETIME($date, month: "long", year: "numeric", day: "numeric", hour: "numeric", minute: "numeric", second: "numeric") }</time>
+
+# Text displayed next to the URL for the source of the service worker (e-g. "Source my/path/to/worker-js")
+serviceworker-worker-source = Ffynhonnell
+
+# Text displayed next to the current status of the service worker.
+serviceworker-worker-status = Statws
+
+## Service Worker status strings: all serviceworker-worker-status-* strings are also
+## defined in aboutdebugging.properties and should be synchronized with them.
+
+# Service Worker status. A running service worker is registered, currently executed, can
+# be debugged and stopped.
+serviceworker-worker-status-running = Rhedeg
+
+# Service Worker status. A stopped service worker is registered but not currently active.
+serviceworker-worker-status-stopped = Aros
+
+# Text displayed when no service workers are visible for the current page. Clicking on the
+# link will open https://developer-mozilla-org/docs/Web/API/Service_Worker_API/Using_Service_Workers
+serviceworker-empty-intro = Mae angen cofrestru Gweithiwr Gwasanaeth i'w archwilio yma. <a>Dysgu rhagor</a>
+
+# Text displayed when there are no Service Workers to display for the current page,
+# introducing hints to debug Service Worker issues.
+serviceworker-empty-suggestions = Os ddylai'r ffenestr gyfredol fod â gweithiwr gwasanaeth, dyma rhai pethau i chi eu profi.
+
+# Suggestion to check for errors in the Console to investigate why a service worker is not
+# registered. Clicking on the link opens the webconsole.
+serviceworker-empty-suggestions-console = Chwilio drwy wallau yn y Consol. <a>Agor y Consol</a>
+
+# Suggestion to use the debugger to investigate why a service worker is not registered.
+# Clicking on the link will switch from the Application panel to the debugger.
+serviceworker-empty-suggestions-debugger = Camu drwy gofrestriad eich Gweithiwr Gwasanaeth a chwilio am eithriadau. <a>Agor y Dadfygiwr</a>
+
+# Suggestion to go to about:debugging in order to see Service Workers for all domains.
+# Clicking on the link will open about:debugging in a new tab.
+serviceworker-empty-suggestions-aboutdebugging = Archwilio'r Gweithwyr Gwasanaeth o barthau eraill. <a>Agor about:debugging</a>
+
+# Text displayed when no service workers are visible for the current page.
+serviceworker-empty-intro2 = Heb ganfod unrhyw weithwyr gwasanaeth
+
+# Link will open https://developer.mozilla.org/docs/Web/API/Service_Worker_API/Using_Service_Workers
+serviceworker-empty-intro-link = Dysgu mwy
+
+# Text displayed when there are no Service Workers to display for the current page,
+# introducing hints to debug Service Worker issues.
+# <a> and <span> are links that will open the webconsole and the debugger, respectively.
+serviceworker-empty-suggestions2 = Os dylai'r gweithiwr cyfredol fod â gweithiwr gwasanaeth, fe allech chi chwilio am wallau yn y <a>Consol</a> neu gamu trwy'ch cofrestriad gweithiwr gwasanaeth yn y <span>Dadfygiwr</span>.
+
+# Suggestion to go to about:debugging in order to see Service Workers for all domains.
+# Link will open about:debugging in a new tab.
+serviceworker-empty-suggestions-aboutdebugging2 = Gweld gweithwyr gwasanaeth o barthau eraill
+
+# Header for the Manifest page when we have an actual manifest
+manifest-view-header = Maniffest Ap
+
+# Header for the Manifest page when there's no manifest to inspect
+# The link will open https://developer.mozilla.org/en-US/docs/Web/Manifest
+manifest-empty-intro = Mae angen ychwanegu Maniffest ap gwe i'w archwilio yma. <a>Dysgu rhagor</a>
+
+# Header for the Manifest page when there's no manifest to inspect
+manifest-empty-intro2 = Heb ganfod maniffesto ap gwe
+
+# The link will open https://developer.mozilla.org/en-US/docs/Web/Manifest
+manifest-empty-intro-link = Dysgwch sut i ychwanegu maniffest
+
+# Header for the Errors and Warnings section of Manifest inspection displayed in the application panel.
+manifest-item-warnings = Gwallau a Rhybuddion
+
+# Header for the Identity section of Manifest inspection displayed in the application panel.
+manifest-item-identity = Hunaniaeth
+
+# Header for the Presentation section of Manifest inspection displayed in the application panel.
+manifest-item-presentation = Cyflwyniad
+
+# Header for the Icon section of Manifest inspection displayed in the application panel.
+manifest-item-icons = Eiconau
+
+# Text displayed while we are loading the manifest file
+manifest-loading = Llwytho maniffest ...
+
+# Text displayed when the manifest has been successfully loaded
+manifest-loaded-ok = Manifest wedi'i lwytho.
+
+# Text displayed as a caption when there has been an error while trying to
+# load the manifest
+manifest-loaded-error = Bu gwall wrth lwytho'r maniffest:
+
+# Text displayed as an error when there has been a Firefox DevTools error while
+# trying to load the manifest
+manifest-loaded-devtools-error = Gwall Firefox DevTools
+
+# Text displayed when the page has no manifest available
+manifest-non-existing = Heb ganfod maniffest i'w arolygu
+
+# Text displayed when the page has a manifest embedded in a Data URL and
+# thus we cannot link to it.
+manifest-json-link-data-url = Mae'r maniffest wedi'i fewnosod mewn URL Data.
+
+# Text displayed at manifest icons to label their purpose, as declared
+# in the manifest.
+manifest-icon-purpose = Pwrpas: <code>{ $purpose }</code>
+
+# Text displayed as the alt attribute for <img> tags showing the icons in the
+# manifest.
+manifest-icon-img =
+    .alt = Eicon
+
+# Text displayed as the title attribute for <img> tags showing the icons in the
+# manifest. `$sizes` is a user-dependent string that has been parsed as a
+# space-separated list of `<width>x<height>` sizes or the keyword `any`.
+manifest-icon-img-title = Eicon gyda meintiau: { $sizes }
+
+# Text displayed as the title attribute for <img> tags showing the icons in the
+# manifest, in case there's no icon size specified by the user
+manifest-icon-img-title-no-sizes = Eicon maint amhenodol
+
+# Sidebar navigation item for Manifest sidebar item section
+sidebar-item-manifest = Maniffest
+    .alt = Eicon Maniffest
+    .title = Maniffest
+
+# Sidebar navigation item for Service Workers sidebar item section
+sidebar-item-service-workers = Gweithwyr Gwasanaeth
+    .alt = Eicon Gweithwyr Gwasanaeth
+    .title = Gweithwyr Gwasanaeth
+
+# Text for the ALT and TITLE attributes of the warning icon
+icon-warning =
+    .alt = Eicon rhybuddio
+    .title = Rhybudd
+
+# Text for the ALT and TITLE attributes of the error icon
+icon-error =
+    .alt = Eicon gwall
+    .title = Gwall
+
diff --git a/l10n-cy/devtools/client/boxmodel.properties b/l10n-cy/devtools/client/boxmodel.properties
new file mode 100644
index 0000000000..2a95fd2753
--- /dev/null
+++ b/l10n-cy/devtools/client/boxmodel.properties
@@ -0,0 +1,48 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE : FILE This file contains the Layout View strings.
+# The Layout View is a panel displayed in the computed view tab of the Inspector sidebar.
+
+# LOCALIZATION NOTE : FILE The correct localization of this file might be to
+# keep it in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (boxmodel.title) This is the title of the box model panel and is
+# displayed as a label.
+boxmodel.title=Model Blwch
+
+# LOCALIZATION NOTE: (boxmodel.geometryButton.tooltip) This label is displayed as a
+# tooltip that appears when hovering over the button that allows users to edit the
+# position of an element in the page.
+boxmodel.geometryButton.tooltip=Golygu safle
+
+# LOCALIZATION NOTE: (boxmodel.propertiesLabel) This label is displayed as the header
+# for showing and collapsing the properties underneath the box model in the layout view
+boxmodel.propertiesLabel=Priodoleddau Model Blwch
+
+# LOCALIZATION NOTE (boxmodel.propertiesHideLabel):
+# This is the spoken label for the twisty.
+# If the properties are currently showing, it will say "Hide".
+boxmodel.propertiesHideLabel=Cuddio
+
+# LOCALIZATION NOTE (boxmodel.propertiesShowLabel):
+# This is the spoken label for the twisty.
+# If the properties are currently hidden, it will say "Show".
+boxmodel.propertiesShowLabel=Dangos
+
+# LOCALIZATION NOTE: (boxmodel.offsetParent) This label is displayed inside the list of
+# properties, below the box model, in the layout view. It is displayed next to the
+# position property, when position is absolute, relative, sticky. This label tells users
+# what the DOM node previewed next to it is: an offset parent for the position element.
+boxmodel.offsetParent=atred
+
+# LOCALIZATION NOTE: (boxmodel.offsetParent.title) This label is displayed as a
+# tooltip that appears when hovering over the offset label, inside the list of properties,
+# below the box model, in the layout view. This label tells users
+# what the DOM node previewed next to it is: an offset parent for the position element.
+boxmodel.offsetParent.title=Rhiant offset yr elfen hon
+
diff --git a/l10n-cy/devtools/client/changes.properties b/l10n-cy/devtools/client/changes.properties
new file mode 100644
index 0000000000..80bc8d2798
--- /dev/null
+++ b/l10n-cy/devtools/client/changes.properties
@@ -0,0 +1,64 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE This file contains the strings for the Changes panel accessible from
+# the Inspector sidebar.
+
+# LOCALIZATION NOTE (changes.noChanges): This text is shown when no changes are available.
+changes.noChanges=Heb ganfod newidiadau.
+
+# LOCALIZATION NOTE (changes.noChangesDescription): This text is shown when no changes are
+# available and provides additional context for the purpose of the Changes panel.
+changes.noChangesDescription=Bydd newidiadau i CSS yn yr Arolygydd yn ymddangos yma.
+
+# LOCALIZATION NOTE (changes.inlineStyleSheetLabel): This label appears in the Changes
+# panel above changes done to inline stylesheets. The variable will be replaced with the
+# index of the stylesheet within its document like so: Inline #1
+changes.inlineStyleSheetLabel=%S mewnlin
+
+# LOCALIZATION NOTE (changes.elementStyleLabel): This label appears in the Changes
+# panel above changes done to element styles.
+changes.elementStyleLabel=Elfen
+
+# LOCALIZATION NOTE (changes.iframeLabel): This label appears next to URLs of stylesheets
+# and element inline styles hosted by iframes. Lowercase intentional.
+changes.iframeLabel=iframe
+
+# LOCALIZATION NOTE (changes.contextmenu.copy): Label for "Copy" option in Changes panel
+# context menu
+changes.contextmenu.copy=Copïo
+
+# LOCALIZATION NOTE (changes.contextmenu.copy.accessKey): Access key for "Copy"
+# option in the Changes panel.
+changes.contextmenu.copy.accessKey=C
+
+# LOCALIZATION NOTE (changes.contextmenu.copyAllChanges): Label for "Copy All Changes"
+# option in Changes panel context menu which copies all changed CSS declarations from a
+# stylesheet
+changes.contextmenu.copyAllChanges=Copïo Pob Newid
+
+# LOCALIZATION NOTE (changes.contextmenu.copyAllChangesDescription): Detailed explanation
+# for "Copy All Changes" option in Changes panel. Used as title attribute on "Copy All
+# Changes" button
+changes.contextmenu.copyAllChangesDescription=Copïo rhestr o'r holl newidiadau CSS i'r clipfwrdd.
+
+# LOCALIZATION NOTE (changes.contextmenu.copyDeclaration): Label for "Copy Declaration"
+# option in Changes panel context menu which copies the target CSS declaration.
+changes.contextmenu.copyDeclaration=Datganiad Copïo
+
+# LOCALIZATION NOTE (changes.contextmenu.copyRule): Label for "Copy Rule" option in
+# Changes panel context menu which copies the complete contents of a CSS rule.
+changes.contextmenu.copyRule=Copïo Rheol
+
+# LOCALIZATION NOTE (changes.contextmenu.copyRuleDescription): Detailed explanation for
+# "Copy Rule" option in Changes panel. Used as title attribute on "Copy Rule" button.
+changes.contextmenu.copyRuleDescription=Copïo cynnwys y rheol CSS hon i'r clipfwrdd.
+
+# LOCALIZATION NOTE (changes.contextmenu.selectAll): Label for "Select All" option in the
+# Changes panel context menu to select all text content.
+changes.contextmenu.selectAll=Dewis Popeth
+
+# LOCALIZATION NOTE (changes.contextmenu.selectAll.accessKey): Access key for "Select All"
+# option in the Changes panel.
+changes.contextmenu.selectAll.accessKey=P
diff --git a/l10n-cy/devtools/client/compatibility.ftl b/l10n-cy/devtools/client/compatibility.ftl
new file mode 100644
index 0000000000..fb0ef8f3a2
--- /dev/null
+++ b/l10n-cy/devtools/client/compatibility.ftl
@@ -0,0 +1,53 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Messages used as headers in the main pane
+
+compatibility-selected-element-header = Elfennau Dewiswyd
+compatibility-all-elements-header = Pob Cyhoeddiad
+
+## Message used as labels for the type of issue
+
+compatibility-issue-deprecated = (anghymeradwy)
+compatibility-issue-experimental = (arbrofol)
+compatibility-issue-prefixneeded = (angen rhagddodiad)
+compatibility-issue-deprecated-experimental = (anghymeradwy, arbrofol)
+
+compatibility-issue-deprecated-prefixneeded = (anghymeradwy, angen rhagddodiad)
+compatibility-issue-experimental-prefixneeded = (arbrofol, angen rhagddodiad)
+compatibility-issue-deprecated-experimental-prefixneeded = anghymeradwy, arbrofol, angen rhagddodiad)
+
+## Messages used as labels and titles for buttons in the footer
+
+compatibility-settings-button-label = Gosodiadau
+compatibility-settings-button-title =
+    .title = Gosodiadau
+compatibility-feedback-button-label = Adborth
+compatibility-feedback-button-title =
+    .title = Adborth
+
+## Messages used as headers in settings pane
+
+compatibility-settings-header = Gosodiadau
+compatibility-target-browsers-header = Porwyr Targed
+
+##
+
+# Text used as the label for the number of nodes where the issue occurred
+# Variables:
+#   $number (Number) - The number of nodes where the issue occurred
+compatibility-issue-occurrences =
+    { $number ->
+        [zero] { $number } digwyddiad
+        [one] { $number } digwyddiad
+        [two] { $number } digwyddiad
+        [few] { $number } digwyddiad
+        [many] { $number } digwyddiad
+       *[other] { $number } digwyddiad
+    }
+
+compatibility-no-issues-found = Dim materion cydnawsedd. wedi'u canfod.
+compatibility-close-settings-button =
+    .title = Cau'r gosodiadau
diff --git a/l10n-cy/devtools/client/components.properties b/l10n-cy/devtools/client/components.properties
new file mode 100644
index 0000000000..bf6e664a1e
--- /dev/null
+++ b/l10n-cy/devtools/client/components.properties
@@ -0,0 +1,24 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used in the shared React components,
+# so files in `devtools/client/shared/components/*`.
+
+# LOCALIZATION NOTE (frame.unknownSource): When we do not know the source filename of
+# a frame, we use this string instead.
+frame.unknownSource=(anhysbys)
+
+# LOCALIZATION NOTE (frame.viewsourceindebugger): The label for the tooltip when hovering over
+# a source link that links to the debugger.
+# %S represents the URL to match in the debugger.
+frame.viewsourceindebugger=Gweld y ffynhonnell yn y Dadfygiwr → %S
+
+# LOCALIZATION NOTE (frame.viewsourceinstyleeditor): The label for the tooltip when hovering over
+# a source link that links to the Style Editor.
+# %S represents the URL to match in the style editor.
+frame.viewsourceinstyleeditor=Gweld y ffynhonnell yn y Golygydd Arddull → %S
+
+# LOCALIZATION NOTE (notificationBox.closeTooltip): The content of a tooltip that
+# appears when hovering over the close button in a notification box.
+notificationBox.closeTooltip=Cau'r neges hon
diff --git a/l10n-cy/devtools/client/debugger.properties b/l10n-cy/devtools/client/debugger.properties
new file mode 100644
index 0000000000..59424fdade
--- /dev/null
+++ b/l10n-cy/devtools/client/debugger.properties
@@ -0,0 +1,1131 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Debugger
+# which is available from the Web Developer sub-menu -> 'Debugger'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (collapseSources): This is the tooltip for the button
+# that collapses the Sources and Outlines panes in the debugger UI.
+collapseSources=Cau paenau Ffynonellau ac Amlinellau
+
+# LOCALIZATION NOTE (collapseBreakpoints): This is the tooltip for the button
+# that collapses the Breakpoints panes in the debugger UI.
+collapseBreakpoints=Paen Cau Torbwyntiau
+
+# LOCALIZATION NOTE (copyToClipboard.label): This is the text that appears in the
+# context menu to copy the text that the user selected.
+copyToClipboard.label=Copïo i'r clipfwrdd
+copyToClipboard.accesskey=C
+
+# LOCALIZATION NOTE (copySource.label): This is the text that appears in the
+# context menu to copy all of the text in the open file.
+copySource.label=Copïo ffynhonnell testun
+copySource.accesskey=o
+
+# LOCALIZATION NOTE (copySourceUri2): This is the text that appears in the
+# context menu to copy the source URI of file open.
+copySourceUri2=Copïo’r URI ffynhonnell
+copySourceUri2.accesskey=u
+
+# LOCALIZATION NOTE (collapseAll.label): This is the text that appears in the
+# context menu to collapse a directory and all of its subdirectories.
+collapseAll.label=Cau popeth
+
+# LOCALIZATION NOTE (expandAll.label): This is the text that appears in the
+# context menu to expand a directory and all of its subdirectories.
+expandAll.label=Ehangu popeth
+
+# LOCALIZATION NOTE (setDirectoryRoot.label): This is the text that appears in the
+# context menu to set a directory as root directory
+setDirectoryRoot.label=Gosod gwraidd cyfeiriadur
+setDirectoryRoot.accesskey=r
+
+# LOCALIZATION NOTE (removeDirectoryRoot.label): This is the text that appears in the
+# context menu to remove a directory as root directory
+removeDirectoryRoot.label=Tynnu cyfeiriadur gwraidd
+
+# LOCALIZATION NOTE (blackBoxAll.label): Text associated with the blackbox context menu item
+blackBoxAll.label=Blwch du
+
+# LOCALIZATION NOTE (blackBoxAllInGroup.label): This is the text that appears in the
+# context submenu to blackbox all files inside of the selected group
+blackBoxAllInGroup.label=Gosod ffeiliau'r grŵp hwn mewn blwch du
+
+# LOCALIZATION NOTE (unblackBoxAllInGroup.label): This is the text that appears in the
+# context submenu to unblackbox all files inside of the selected group
+unblackBoxAllInGroup.label=Tynnu ffeiliau'r grŵp hwn o'r blwch du
+
+# LOCALIZATION NOTE (blackBoxAllOutsideGroup.label): This is the text that appears in the
+# context submenu to blackbox all files outside of the selected group
+blackBoxAllOutsideGroup.label=Gosod ffeiliau'r grŵp hwn tu allan i'r blwch du
+
+# LOCALIZATION NOTE (unblackBoxAllOutsideGroup.label): This is the text that appears in the
+# context submenu to unblackbox all files outside of the selected group
+unblackBoxAllOutsideGroup.label=Tynnu ffeiliau'r grŵp hwn tu hwnt i'r blwch du
+
+# LOCALIZATION NOTE (blackBoxAllInDir.label): This is the text that appears in the
+# context submenu to blackbox all files inside of the selected directory
+blackBoxAllInDir.label=Gosod ffeiliau'r grŵp hwn yn y cyfeiriadur hwn
+
+# LOCALIZATION NOTE (unblackBoxAllInDir.label): This is the text that appears in the
+# context submenu to unblackbox all files inside of the selected directory
+unblackBoxAllInDir.label=Tynnu ffeiliau'r cyfeiriadur hwn o'r blwch du
+
+# LOCALIZATION NOTE (blackBoxAllOutsideDir.label): This is the text that appears in the
+# context submenu to blackbox all files outside of the selected directory
+blackBoxAllOutsideDir.label=Gosod ffeiliau'r cyfeiriadur hwn tu allan i'r blwch du
+
+# LOCALIZATION NOTE (unblackBoxAllOutsideDir.label: This is the text that appears in the
+# context submenu to unblackbox all files outside of the selected directory
+unblackBoxAllOutsideDir.label=Tynnu ffeiliau'r cyfeiriadur hwn tu allan i'r blwch du
+
+# LOCALIZATION NOTE (ignoreAll.label): Text associated with the ignore context menu item
+ignoreAll.label=anwybyddu
+
+# LOCALIZATION NOTE (ignoreAllInGroup.label): This is the text that appears in the
+# context submenu to ignore all files inside of the selected group
+ignoreAllInGroup.label=Anwybyddu ffeiliau yn y grŵp hwn
+
+# LOCALIZATION NOTE (unignoreAllInGroup.label): This is the text that appears in the
+# context submenu to unignore all files inside of the selected group
+unignoreAllInGroup.label=Peidio anwybyddu ffeiliau yn y grŵp hwn
+
+# LOCALIZATION NOTE (ignoreAllOutsideGroup.label): This is the text that appears in the
+# context submenu to ignore all files outside of the selected group
+ignoreAllOutsideGroup.label=Anwybyddu ffeiliau y tu allan i'r grŵp hwn
+
+# LOCALIZATION NOTE (unignoreAllOutsideGroup.label): This is the text that appears in the
+# context submenu to unignore all files outside of the selected group
+unignoreAllOutsideGroup.label=Peidio anwybyddu ffeiliau y tu allan i'r grŵp hwn
+
+# LOCALIZATION NOTE (ignoreAllInDir.label): This is the text that appears in the
+# context submenu to ignore all files inside of the selected directory
+ignoreAllInDir.label=Anwybyddu ffeiliau yn y cyfeiriadur hwn
+
+# LOCALIZATION NOTE (unignoreAllInDir.label): This is the text that appears in the
+# context submenu to unignore all files inside of the selected directory
+unignoreAllInDir.label=Peidio anwybyddu ffeiliau yn y cyfeiriadur hwn
+
+# LOCALIZATION NOTE (ignoreAllOutsideDir.label): This is the text that appears in the
+# context submenu to ignore all files outside of the selected directory
+ignoreAllOutsideDir.label=Anwybyddu ffeiliau y tu allan i'r cyfeiriadur hwn
+
+# LOCALIZATION NOTE (unignoreAllOutsideDir.label: This is the text that appears in the
+# context submenu to unignore all files outside of the selected directory
+unignoreAllOutsideDir.label=Peidio anwybyddu ffeiliau y tu allan i'r cyfeiriadur hwn
+
+# LOCALIZATION NOTE (copyFunction.label): This is the text that appears in the
+# context menu to copy the function the user selected
+copyFunction.label=Swyddogaeth Copïo
+copyFunction.accesskey=S
+
+# LOCALIZATION NOTE (copyStackTrace): This is the text that appears in the
+# context menu to copy the stack trace methods, file names and row number.
+copyStackTrace=Copïo Olrhain Stac
+copyStackTrace.accesskey=c
+
+# LOCALIZATION NOTE (restartFrame): This is the text that appears in the
+# context menu to restart a frame.
+restartFrame=Ailgychwyn ffrâm
+restartFrame.accesskey=a
+
+# LOCALIZATION NOTE (expandSources): This is the tooltip for the button
+# that expands the Sources and Outlines panes in the debugger UI.
+expandSources=Agor paenau Ffynonellau ac Amlinellau
+
+# LOCALIZATION NOTE (expandBreakpoints): This is the tooltip for the button
+# that expands the Breakpoints panes in the debugger UI.
+expandBreakpoints=Ehangu paen Torbwyntiau
+
+# LOCALIZATION NOTE (evaluateInConsole.label): Editor right-click menu item
+# to execute selected text in browser console.
+evaluateInConsole.label=Gwerthuso o fewn consol
+
+# LOCALIZATION NOTE (pauseButtonTooltip): The tooltip that is displayed for the pause
+# button when the debugger is in a running state.
+pauseButtonTooltip=Oedi %S
+
+# LOCALIZATION NOTE (pausePendingButtonTooltip): The tooltip that is displayed for
+# the pause button after it's been clicked but before the next JavaScript to run.
+pausePendingButtonTooltip=Disgwyl y gweithrediad nesaf
+
+# LOCALIZATION NOTE (resumeButtonTooltip): The label that is displayed on the pause
+# button when the debugger is in a paused state.
+resumeButtonTooltip=Ailgychwyn %S
+
+# LOCALIZATION NOTE (stepOverTooltip): The label that is displayed on the
+# button that steps over a function call.
+stepOverTooltip=Camu Dros %S
+
+# LOCALIZATION NOTE (stepInTooltip): The label that is displayed on the
+# button that steps into a function call.
+stepInTooltip=Camu i Mewn %S
+
+# LOCALIZATION NOTE (stepOutTooltip): The label that is displayed on the
+# button that steps out of a function call.
+stepOutTooltip=Camu Allan %S
+
+# LOCALIZATION NOTE (skipPausingTooltip.label): The tooltip text for disabling all
+# breakpoints and pausing triggers
+skipPausingTooltip.label=Dad-weithredu torbwyntiau
+
+# LOCALIZATION NOTE (undoSkipPausingTooltip.label): The tooltip text for enabling all
+# breakpoints and pausing triggers
+undoSkipPausingTooltip.label=Gweithredu torbwyntiau
+
+# LOCALIZATION NOTE (pauseOnExceptionsItem2): The pause on exceptions checkbox description
+# when the debugger will pause on all exceptions.
+pauseOnExceptionsItem2=Oedi'r eithriadau
+
+# LOCALIZATION NOTE (pauseOnCaughtExceptionsItem): The pause on exceptions checkbox description
+# when the debugger should pause on caught exceptions
+pauseOnCaughtExceptionsItem=Oedi wrth eithriadau wedi eu cipio
+
+# LOCALIZATION NOTE (threadsHeader): The text to describe the threads header
+threadsHeader=Edafedd
+
+# LOCALIZATION NOTE (mainThread): The text to describe the thread of the
+# program as opposed to worker threads.
+mainThread=Prif Edafedd
+
+# LOCALIZATION NOTE (noSourcesText): The text to display in the sources list
+# when there are no sources.
+noSourcesText=Nid oes gan y dudalen ffynonellau.
+
+# LOCALIZATION NOTE (eventListenersHeader1): The text to display in the events
+# header.
+eventListenersHeader1=Torbwyntiau Gwrandäwr Digwyddiad
+
+# LOCALIZATION NOTE (noDomMutationBreakpoints): The text to
+# display in the DOM Mutation Breakpoints pane when there are no events.
+# %S will be replaced by an active link using inspectorTool as text
+noDomMutationBreakpoints=Rhowch glic de i elfen yn y %S a dewis “Toriad ar…” i ychwanegu torbwynt
+
+# LOCALIZATION NOTE (inspectorTool): The text to describe the the Inspector tool
+inspectorTool=Archwiliwr
+
+# LOCALIZATION NOTE (eventListenersHeader1.placeholder): The placeholder text in
+# the event search input bar
+eventListenersHeader1.placeholder=Hidlo yn ôl math o ddigwyddiad
+
+# LOCALIZATION NOTE (domMutationHeader): The text to display in the
+# DOM Mutation Breakpoints header
+domMutationHeader=Torbwyntiau Treiglad DOM
+
+# LOCALIZATION NOTE (domMutationTypes.attribute): The text to display in the
+# DOM Mutation Breakpoints panel for an attribute change
+domMutationTypes.attribute=Addasu Priodoledd
+
+# LOCALIZATION NOTE (domMutationTypes.removal): The text to display in the
+# DOM Mutation Breakpoints panel for a DOM node removal
+domMutationTypes.removal=Tynnu Nodau
+
+# LOCALIZATION NOTE (domMutationTypes.subtree): The text to display in the
+# DOM Mutation Breakpoints panel for a DOM subtree change
+domMutationTypes.subtree=Addasu Is-goeden
+
+# LOCALIZATION NOTE (sources.search.key2): Key shortcut to open the search for
+# searching all the source files the debugger has seen.
+# Do not localize "CmdOrCtrl+P", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+sources.search.key2=CmdOrCtrl+P
+
+# LOCALIZATION NOTE (sources.search.alt.key): A second key shortcut to open the
+# search for searching all the source files the debugger has seen.
+# Do not localize "CmdOrCtrl+O", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+sources.search.alt.key=CmdOrCtrl+O
+
+# LOCALIZATION NOTE (projectTextSearch.key): A key shortcut to open the
+# full project text search for searching all the files the debugger has seen.
+# Do not localize "CmdOrCtrl+Shift+F", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+projectTextSearch.key=CmdOrCtrl+Shift+F
+
+# LOCALIZATION NOTE (allShortcut.key): A key shortcut to open the
+# modal of full shortcuts list.
+# Do not localize "CmdOrCtrl+/", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+allShortcut.key=CmdOrCtrl+/
+
+# LOCALIZATION NOTE (functionSearch.key): A key shortcut to open the
+# modal for searching functions in a file.
+# Do not localize "CmdOrCtrl+Shift+O", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+functionSearch.key=CmdOrCtrl+Shift+O
+
+# LOCALIZATION NOTE (toggleBreakpoint.key): A key shortcut to toggle
+# breakpoints.
+# Do not localize "CmdOrCtrl+B", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+toggleBreakpoint.key=CmdOrCtrl+B
+
+# LOCALIZATION NOTE (toggleCondPanel.breakpoint.key): A key shortcut to toggle
+# the conditional panel for breakpoints.
+# Do not localize "CmdOrCtrl+Shift+B", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+toggleCondPanel.breakpoint.key=CmdOrCtrl+Shift+B
+
+# LOCALIZATION NOTE (toggleCondPanel.logPoint.key): A key shortcut to toggle
+# the conditional panel for log points.
+# Do not localize "CmdOrCtrl+Shift+Y", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+toggleCondPanel.logPoint.key=CmdOrCtrl+Shift+Y
+
+# LOCALIZATION NOTE (stepOut.key): A key shortcut to
+# step out.
+stepOut.key=Shift+F11
+
+# LOCALIZATION NOTE (shortcuts.header.editor): Sections header in
+# the shortcuts modal for keyboard shortcuts related to editing.
+shortcuts.header.editor=Golygydd
+
+# LOCALIZATION NOTE (shortcuts.header.stepping): Sections header in
+# the shortcuts modal for keyboard shortcuts related to stepping.
+shortcuts.header.stepping=Stepio
+
+# LOCALIZATION NOTE (shortcuts.header.search): Sections header in
+# the shortcuts modal for keyboard shortcuts related to search.
+shortcuts.header.search=Chwilio
+
+# LOCALIZATION NOTE (projectTextSearch.placeholder): A placeholder shown
+# when searching across all of the files in a project.
+projectTextSearch.placeholder=Canfod yn y ffeiliau…
+
+# LOCALIZATION NOTE (projectTextSearch.noResults): The center pane Text Search
+# message when the query did not match any text of all files in a project.
+projectTextSearch.noResults=Heb ganfod canlyniadau
+
+# LOCALIZATION NOTE (sourceSearch.search.key2): Key shortcut to open the search
+# for searching within a the currently opened files in the editor
+# Do not localize "CmdOrCtrl+F", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+sourceSearch.search.key2=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (sourceSearch.search.placeholder): placeholder text in
+# the source search input bar
+sourceSearch.search.placeholder=Chwilio mewn ffeiliau…
+
+# LOCALIZATION NOTE (sourceSearch.search.placeholder2): placeholder text in
+# the source search input bar
+sourceSearch.search.placeholder2=Canfod mewn ffeil…
+
+# LOCALIZATION NOTE (sourceSearch.search.again.key3): Key shortcut to highlight
+# the next occurrence of the last search triggered from a source search
+# Do not localize "Cmd+G", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+sourceSearch.search.again.key3=Cmd+G
+
+# LOCALIZATION NOTE (sourceSearch.search.againPrev.key3): Key shortcut to highlight
+# the previous occurrence of the last search triggered from a source search
+# Do not localize "Cmd+Shift+G", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+sourceSearch.search.againPrev.key3=Cmd+Shift+G
+
+# LOCALIZATION NOTE (sourceSearch.resultsSummary2): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Shows a summary of the number of matches for autocomplete
+sourceSearch.resultsSummary2=#1 canlyniadau;#1 canlyniad;#1 canlyniad;#1 canlyniad;#1 canlyniad;#1 canlyniad
+
+# LOCALIZATION NOTE (breakpointHeadingMenuItem.*): The text for all the elements
+# that are displayed in the breakpoint headings menu item popup.
+breakpointHeadingsMenuItem.enableInSource.label=Galluogi torbwyntiau
+breakpointHeadingsMenuItem.enableInSource.accesskey=G
+breakpointHeadingsMenuItem.disableInSource.label=Analluogi torbwyntiau
+breakpointHeadingsMenuItem.disableInSource.accesskey=A
+breakpointHeadingsMenuItem.removeInSource.label=Tynnu torbwyntiau
+breakpointHeadingsMenuItem.removeInSource.accesskey=A
+
+# LOCALIZATION NOTE (breakpointMenuItem): The text for all the elements that
+# are displayed in the breakpoints menu item popup.
+breakpointMenuItem.enableSelf2.label=Galluogi
+breakpointMenuItem.enableSelf2.accesskey=G
+breakpointMenuItem.disableSelf2.label=Analluogi
+breakpointMenuItem.disableSelf2.accesskey=A
+breakpointMenuItem.deleteSelf2.label=Tynnu
+breakpointMenuItem.deleteSelf2.accesskey=T
+breakpointMenuItem.disabledbg.label=Peidiwch byth ag oedi yma
+breakpointMenuItem.enabledbg.label=Oedi yma
+breakpointMenuItem.enableOthers2.label=Galluogi eraill
+breakpointMenuItem.enableOthers2.accesskey=e
+breakpointMenuItem.disableOthers2.label=Analluogi eraill
+breakpointMenuItem.disableOthers2.accesskey=n
+breakpointMenuItem.deleteOthers2.label=Tynnu eraill
+breakpointMenuItem.deleteOthers2.accesskey=y
+breakpointMenuItem.enableAll2.label=Galluogi popeth
+breakpointMenuItem.enableAll2.accesskey=p
+breakpointMenuItem.disableAll2.label=Analluogi popeth
+breakpointMenuItem.disableAll2.accesskey=o
+breakpointMenuItem.deleteAll2.label=Tynnu popeth
+breakpointMenuItem.deleteAll2.accesskey=n
+breakpointMenuItem.removeCondition2.label=Tynnu'r cyflwr
+breakpointMenuItem.removeCondition2.accesskey=c
+breakpointMenuItem.addCondition2.label=Ychwanegu'r cyflwr
+breakpointMenuItem.addCondition2.accesskey=Y
+breakpointMenuItem.editCondition2.label=Golygu'r cyflwr
+breakpointMenuItem.editCondition2.accesskey=G
+breakpointMenuItem.enableSelf=Galluogi torbwynt
+breakpointMenuItem.disableSelf=Anablu torbwynt
+breakpointMenuItem.deleteSelf=Tynnu torbwynt
+breakpointMenuItem.enableOthers=Galluogi eraill
+breakpointMenuItem.disableOthers=Analluogi eraill
+breakpointMenuItem.deleteOthers=Tynnu eraill
+breakpointMenuItem.enableAll=Galluogi pob torbwynt
+breakpointMenuItem.disableAll=Anablu pob torbwynt
+breakpointMenuItem.deleteAll=Tynnu pob torbwynt
+breakpointMenuItem.disableAllAtLine.label=Analluogi torbwyntiau ar y linell
+breakpointMenuItem.disableAllAtLine.accesskey=A
+breakpointMenuItem.enableAllAtLine.label=Galluogi torbwyntiau ar y linell
+breakpointMenuItem.enableAllAtLine.accesskey=G
+breakpointMenuItem.removeAllAtLine.label=Tynnu torbwyntiau ar y linell
+breakpointMenuItem.removeAllAtLine.accesskey=l
+
+# LOCALIZATION NOTE (breakpoints.header): Breakpoints right sidebar pane header.
+breakpoints.header=Torbwyntiau
+
+# LOCALIZATION NOTE (breakpoints.enable): The text that may appear as a tooltip
+# when hovering over the 'disable breakpoints' switch button in right sidebar
+breakpoints.enable=Galluogi Torbwynt
+
+# LOCALIZATION NOTE (breakpoints.disable): The text that may appear as a tooltip
+# when hovering over the 'disable breakpoints' switch button in right sidebar
+breakpoints.disable=Analluogi Torbwynt
+
+# LOCALIZATION NOTE (breakpoints.removeBreakpointTooltip): The tooltip that is displayed
+# for remove breakpoint button in right sidebar
+breakpoints.removeBreakpointTooltip=Tynnu Torbwynt
+
+# LOCALIZATION NOTE (callStack.header): Call Stack right sidebar pane header.
+callStack.header=Galw Stac
+
+# LOCALIZATION NOTE (callStack.notPaused): Call Stack right sidebar pane
+# message when not paused.
+callStack.notPaused=Heb Oedi
+
+# LOCALIZATION NOTE (callStack.collapse): Call Stack right sidebar pane
+# message to hide some of the frames that are shown.
+callStack.collapse=Cau Rhesi
+
+# LOCALIZATION NOTE (callStack.expand): Call Stack right sidebar pane
+# message to show more of the frames.
+callStack.expand=Ehangu Rhesi
+
+# LOCALIZATION NOTE (callStack.group.expandTooltip): The text that will appear
+# when hovering a collapsed Group of frames in the callStack panel. `frames` is
+# always plural since a group can only exist if it contain more that 1 frame.
+# %S is replaced by the name of the library of the frames in the group.
+# example: `Show React frames`.
+callStack.group.expandTooltip=Dangos fframiau %S
+
+# LOCALIZATION NOTE (callStack.group.collapseTooltip): The text that will appear
+# when hovering an expanded Group of frames in the callStack panel. `frames` is
+# always plural since a group can only exist if it contain more that 1 frame.
+# %S is replaced by the name of the library of the frames in the group.
+# example: `Collapse React frames`.
+callStack.group.collapseTooltip=Cau fframiau %S
+
+# LOCALIZATION NOTE (editor.searchResults1): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Editor Search bar message to summarize the selected search result. e.g. 5 of 10 results.
+editor.searchResults1=%d o #1 canlyniadau;%d o #1 canlyniad;%d o #1 canlyniad;%d o #1 canlyniad;%d o #1 canlyniad;%d o #1 canlyniad
+
+# LOCALIZATION NOTE (editor.noResultsFound): Editor Search bar message
+# for when no results found.
+editor.noResultsFound=Heb ganfod canlyniadau
+
+# LOCALIZATION NOTE (editor.searchResults.nextResult): Editor Search bar
+# tooltip for traversing to the Next Result
+editor.searchResults.nextResult=Canlyniad Nesaf
+
+# LOCALIZATION NOTE (editor.searchResults.prevResult): Editor Search bar
+# tooltip for traversing to the Previous Result
+editor.searchResults.prevResult=Canlyniad Blaenorol
+
+# LOCALIZATION NOTE (editor.continueToHere.label): Editor gutter context
+# menu item for jumping to a new paused location
+editor.continueToHere.label=Parhau i Yma
+editor.continueToHere.accesskey=Y
+
+# LOCALIZATION NOTE (editor.addBreakpoint): Editor gutter context menu item
+# for adding a breakpoint on a line.
+editor.addBreakpoint=Ychwanegu Torbwynt
+
+# LOCALIZATION NOTE (editor.disableBreakpoint): Editor gutter context menu item
+# for disabling a breakpoint on a line.
+editor.disableBreakpoint=Analluogi Torbwynt
+editor.disableBreakpoint.accesskey=G
+
+# LOCALIZATION NOTE (editor.enableBreakpoint): Editor gutter context menu item
+# for enabling a breakpoint on a line.
+editor.enableBreakpoint=Galluogi Torbwynt
+
+# LOCALIZATION NOTE (editor.removeBreakpoint): Editor gutter context menu item
+# for removing a breakpoint on a line.
+editor.removeBreakpoint=Tynnu Torbwynt
+
+# LOCALIZATION NOTE (editor.addConditionBreakpoint): Editor gutter context
+# menu item for adding a breakpoint condition on a line.
+editor.addConditionBreakpoint=Ychwanegu cyflwr
+editor.addConditionBreakpoint.accesskey=c
+
+# LOCALIZATION NOTE (editor.editConditionBreakpoint): Editor gutter context menu item
+# for setting a breakpoint condition on a line.
+editor.editConditionBreakpoint=Golygu cyflwr
+
+# LOCALIZATION NOTE (editor.addLogPoint): Editor gutter context
+# menu item for adding a log point on a line.
+editor.addLogPoint=Ychwanegu cofnod
+editor.addLogPoint.accesskey=f
+
+# LOCALIZATION NOTE (editor.editLogPoint): Editor gutter context menu item
+# for editing a log point already set on a line.
+editor.editLogPoint=Golygu cofnod
+editor.editLogPoint.accesskey=G
+
+# LOCALIZATION NOTE (editor.removeLogPoint): Context menu item for removing
+# a log point on a line.
+editor.removeLogPoint.label=Tynnu cofnod
+editor.removeLogPoint.accesskey=T
+
+# LOCALIZATION NOTE (editor.conditionalPanel.placeholder2): Placeholder text for
+# input element inside ConditionalPanel component
+editor.conditionalPanel.placeholder2=Cyflwr torbwynt, e.e. items.length> 0
+
+# LOCALIZATION NOTE (editor.conditionalPanel.logPoint.placeholder2): Placeholder text for
+# input element inside ConditionalPanel component when a log point is set
+editor.conditionalPanel.logPoint.placeholder2=Neges cofnod, e.e. displayName
+
+# LOCALIZATION NOTE (editor.jumpToMappedLocation1): Context menu item
+# for navigating to a source mapped location
+editor.jumpToMappedLocation1=Neidio i leoliad %S
+editor.jumpToMappedLocation1.accesskey=n
+
+# LOCALIZATION NOTE (downloadFile.label): Context menu item
+# for downloading a source's content
+downloadFile.label=Llwytho ffeil i lawr
+downloadFile.accesskey=L
+
+# LOCALIZATION NOTE (inlinePreview.show.label): Context menu item
+# for showing the inline preview blocks
+inlinePreview.show.label=Dangos rhagolwg mewnlin
+
+# LOCALIZATION NOTE (inlinePreview.hide.label): Context menu item
+# for hiding the inline preview block
+inlinePreview.hide.label=Cuddio rhagolwg mewnlin
+
+# LOCALIZATION NOTE (inlinePreview.toggle.label): Context menu item
+# that will toggle display of inline preview
+inlinePreview.toggle.label=Rhagolwg Newidyn Mewnol
+
+# LOCALIZATION NOTE (inlinePreview.toggle.tooltip): Context menu item
+# tooltip that will describe toggling inline preview
+inlinePreview.toggle.tooltip=Dangos rhagolwg mewnlin yn y golygydd dadfygio
+
+# LOCALIZATION NOTE (editorWrapping.show.label): Context menu item
+# for showing the wrap lines block
+editorWrapping.show.label=Llinellau lapio
+
+# LOCALIZATION NOTE (editorWrapping.hide.label): Context menu item
+# for showing the wrap lines block
+editorWrapping.hide.label=Llinellau heb eu lapio
+
+# LOCALIZATION NOTE (editorWrapping.toggle.label): Context menu item
+# label for toggling the lines wrapping feature
+editorWrapping.toggle.label=Llinellau Lapio
+
+# LOCALIZATION NOTE (editorWrapping.toggle.tooltip): Context menu item
+# tooltip for toggling the lines wrapping feature
+editorWrapping.toggle.tooltip=Llinellau lapio yn y golygydd dadfygio
+
+# LOCALIZATION NOTE (settings.button.label): Label for Settings button
+settings.button.label=Dewisiadau Dadfygio
+
+# LOCALIZATION NOTE (settings.disableJavaScript.label): Context menu item
+# label for disabling JavaScript
+settings.disableJavaScript.label=Analluogi JavaScript
+
+# LOCALIZATION NOTE (settings.disableJavaScript.tooltip): Context menu item
+# tooltip for disabling JavaScript
+settings.disableJavaScript.tooltip=Yn analluogi JavaScript (Angen ail gychwyn)
+
+# LOCALIZATION NOTE (settings.toggleSourceMaps.tooltip): Context menu item
+# tooltip for toggling the source maps feature
+settings.toggleSourceMaps.tooltip=Galluogi Mapiau Ffynhonnell i adael i DevTools lwytho'ch ffynonellau gwreiddiol yn ogystal â'r rhai a gynhyrchwyd gennych
+
+# LOCALIZATION NOTE (settings.toggleSourceMaps.label): Context menu item
+# label for toggling the source maps feature
+settings.toggleSourceMaps.label=Mapiau Ffynhonnell
+
+# LOCALIZATION NOTE (preview.noProperties): Label shown in the preview
+# popup when there are no properties to show.
+preview.noProperties=Dim priodweddau
+
+# LOCALIZATION NOTE (framework.disableGrouping): This is the text that appears in the
+# context menu to disable framework grouping.
+framework.disableGrouping=Analluogi Grwpio Fframwaith
+framework.disableGrouping.accesskey=w
+
+# LOCALIZATION NOTE (framework.enableGrouping): This is the text that appears in the
+# context menu to enable framework grouping.
+framework.enableGrouping=Galluogi Grwpio Fframwaith
+framework.enableGrouping.accesskey=w
+
+# LOCALIZATION NOTE (generated): Source Map term for a server source location
+generated=cynhyrchwyd
+
+# LOCALIZATION NOTE (original): Source Map term for a debugger UI source location
+original=gwreiddiol
+
+# LOCALIZATION NOTE (expressions.placeholder): Placeholder text for expression
+# input element
+expressions.placeholder=Ychwanegu Mynegiad Gwylio
+
+# LOCALIZATION NOTE (expressions.errorMsg): Error text for expression
+# input element
+expressions.errorMsg=Mynegiad annilys…
+expressions.label=Ychwanegu mynegiant gwylio
+expressions.accesskey=e
+expressions.remove.tooltip=Tynnu mynegiad gwylio
+
+# LOCALIZATION NOTE (xhrBreakpoints.header): The pause on any XHR breakpoints headings
+xhrBreakpoints.header=Torbwyntiau XHR
+xhrBreakpoints.placeholder=Torri pan fydd URL yn cynnwys
+xhrBreakpoints.label=Ychwanegu torbwynt XHR
+
+# LOCALIZATION NOTE (xhrBreakpoints.item.label): message displayed when reaching a breakpoint for XHR requests. %S is replaced by the path provided as condition for the breakpoint.
+xhrBreakpoints.item.label=Mae'r URL yn cynnwys “%S”
+
+# LOCALIZATION NOTE (pauseOnAnyXHR): The pause on any XHR checkbox description
+# when the debugger will pause on any XHR requests.
+pauseOnAnyXHR=Oedi ar unrhyw URL
+
+# LOCALIZATION NOTE (watchpoints.submenu): This is the text for the watchpoints sub-menu.
+watchpoints.submenu=Torri ar…
+
+# LOCALIZATION NOTE (watchpoints.getWatchpoint): This is the text that appears in the
+# watchpoints sub-menu to add a "get" watchpoint on an object property.
+watchpoints.getWatchpoint=Priodwedd get
+
+# LOCALIZATION NOTE (watchpoints.setWatchpoint): This is the text that appears in the
+# watchpoints submenu to add a "set" watchpoint on an object property.
+watchpoints.setWatchpoint=Priodwedd set
+
+# LOCALIZATION NOTE (watchpoints.getOrSetWatchpoint): This is the text that appears in the
+# watchpoints submenu to add a "set" watchpoint on an object property.
+watchpoints.getOrSetWatchpoint=Priodwedd get neu set
+
+# LOCALIZATION NOTE (watchpoints.removeWatchpoint): This is the text that appears in the
+# context menu to delete a watchpoint on an object property.
+watchpoints.removeWatchpoint=Tynnu'r pwynt gwylio
+
+# LOCALIZATION NOTE (watchpoints.removeWatchpointTooltip): This is the text that appears in the
+# tooltip to delete a watchpoint on an object property.
+watchpoints.removeWatchpointTooltip=Tynnu'r pwynt gwylio
+
+# LOCALIZATION NOTE (sourceTabs.closeTab): Editor source tab context menu item
+# for closing the selected tab below the mouse.
+sourceTabs.closeTab=Cau tab
+sourceTabs.closeTab.accesskey=c
+sourceTabs.closeTab.key=CmdOrCtrl+W
+
+# LOCALIZATION NOTE (sourceTabs.closeOtherTabs): Editor source tab context menu item
+# for closing the other tabs.
+sourceTabs.closeOtherTabs=Cau eraill
+sourceTabs.closeOtherTabs.accesskey=i
+
+# LOCALIZATION NOTE (sourceTabs.closeTabsToEnd): Editor source tab context menu item
+# for closing the tabs to the end (the right for LTR languages) of the selected tab.
+sourceTabs.closeTabsToEnd=Cau tabiau i'r dde
+sourceTabs.closeTabsToEnd.accesskey=e
+
+# LOCALIZATION NOTE (sourceTabs.closeAllTabs): Editor source tab context menu item
+# for closing all tabs.
+sourceTabs.closeAllTabs=Cau pob tab
+sourceTabs.closeAllTabs.accesskey=a
+
+# LOCALIZATION NOTE (sourceTabs.revealInTree): Editor source tab context menu item
+# for revealing source in tree.
+sourceTabs.revealInTree=Amlygu mewn Coeden
+sourceTabs.revealInTree.accesskey=A
+
+# LOCALIZATION NOTE (sourceTabs.prettyPrint): Editor source tab context menu item
+# for pretty printing the source.
+sourceTabs.prettyPrint=Ffynhonnell Pretty Print
+sourceTabs.prettyPrint.accesskey=p
+
+# LOCALIZATION NOTE (sourceFooter.blackbox): Tooltip text associated
+# with the blackbox button
+sourceFooter.blackbox=Blwchduo'r Ffynhonnell
+
+# LOCALIZATION NOTE (sourceFooter.unblackbox): Tooltip text associated
+# with the blackbox button
+sourceFooter.unblackbox=Dadflwchduo'r Ffynhonnell
+
+# LOCALIZATION NOTE (blackboxContextItem.blackbox): Text associated
+# with the blackbox context menu item
+blackboxContextItem.blackbox=Ffynhonnell blwch du
+blackboxContextItem.blackbox.accesskey=B
+
+# LOCALIZATION NOTE (blackboxContextItem.unblackbox): Text associated
+# with the unblackbox context menu item
+blackboxContextItem.unblackbox=Dim ffynhonnell blwch du
+blackboxContextItem.unblackbox.accesskey=D
+
+# LOCALIZATION NOTE (sourceFooter.ignores): Tooltip text associated
+# with the ignores button
+sourceFooter.ignore=Anwybyddu ffynhonnell
+
+# LOCALIZATION NOTE (sourceFooter.unignore): Tooltip text associated
+# with the ignore button
+sourceFooter.unignore=Peidio anwybyddu ffynhonnell
+
+# LOCALIZATION NOTE (ignoreContextItem.ignore): Text associated
+# with the ignore context menu item
+ignoreContextItem.ignore=Anwybyddu ffynhonnell
+ignoreContextItem.ignore.accesskey=A
+
+# LOCALIZATION NOTE (ignoreContextItem.unignore): Text associated
+# with the unignore context menu item
+ignoreContextItem.unignore=Peidio anwybyddu ffynhonnell
+ignoreContextItem.unignore.accesskey=P
+
+# LOCALIZATION NOTE (sourceFooter.mappedSource): Text associated
+# with a mapped source. %S is replaced by the source map origin.
+sourceFooter.mappedSource=(O %S)
+
+# LOCALIZATION NOTE (sourceFooter.mappedSourceTooltip): Tooltip text associated
+# with a mapped source. %S is replaced by the source map origin.
+sourceFooter.mappedSourceTooltip=(Ffynhonnell wedi ei fapio o %S)
+
+# LOCALIZATION NOTE (sourceFooter.mappedSuffix): Text associated
+# with a mapped source.  Displays next to URLs in tree and tabs.
+sourceFooter.mappedSuffix=(mapio)
+
+# LOCALIZATION NOTE (sourceFooter.currentCursorPosition): Text associated
+# with the current cursor line and column
+sourceFooter.currentCursorPosition=(%S, %S)
+
+# LOCALIZATION NOTE (sourceFooter.currentCursorPosition.tooltip): Text associated
+# with the current cursor line and column
+sourceFooter.currentCursorPosition.tooltip=(Llinell %1$S, colofn %2$S)
+
+# LOCALIZATION NOTE (sourceTabs.closeTabButtonTooltip): The tooltip that is displayed
+# for close tab button in source tabs.
+sourceTabs.closeTabButtonTooltip=Cau tab
+
+# LOCALIZATION NOTE (scopes.header): Scopes right sidebar pane header.
+scopes.header=Sgopau
+
+# LOCALIZATION NOTE (scopes.notAvailable): Scopes right sidebar pane message
+# for when the debugger is paused, but there isn't pause data.
+scopes.notAvailable=Sgopau Ddim ar Gael
+
+# LOCALIZATION NOTE (scopes.notPaused): Scopes right sidebar pane message
+# for when the debugger is not paused.
+scopes.notPaused=Heb Oedi
+
+# LOCALIZATION NOTE (scopes.mapping.label): Scopes right sidebar pane
+# tooltip for checkbox and label
+scopes.mapping.label=Mapio enwau newidiol gwreiddiol
+
+# LOCALIZATION NOTE (eventlisteners.log.label): Event listeners tooltip for
+# checkbox and label
+eventlisteners.log.label=Cofnodi digwyddiadau i'r consol
+
+# LOCALIZATION NOTE (eventlisteners.log): Checkbox label for logging events
+eventlisteners.log=Cofnod
+
+# LOCALIZATION NOTE (scopes.helpTooltip.label): Scopes right sidebar pane
+# icon tooltip for link to MDN
+scopes.helpTooltip.label=Dysgu rhagor ystodau mapio
+
+# LOCALIZATION NOTE (scopes.map.label): Checkbox label to map scopes
+scopes.map.label=Mapio
+
+# LOCALIZATION NOTE (scopes.block): Refers to a block of code in
+# the scopes pane when the debugger is paused.
+scopes.block=Bloc
+
+# LOCALIZATION NOTE (sources.header): Sources left sidebar header
+sources.header=Ffynonellau
+
+# LOCALIZATION NOTE (outline.header): Outline left sidebar header
+outline.header=Amlinell
+
+# LOCALIZATION NOTE (outline.placeholder): Placeholder text for the filter input
+# element
+outline.placeholder=Hidlo swyddogaethau
+
+# LOCALIZATION NOTE (outline.sortLabel): Label for the sort button
+outline.sortLabel=Trefnu yn ôl enw
+
+# LOCALIZATION NOTE (outline.noFunctions): Outline text when there are no functions to display
+outline.noFunctions=Dim swyddogaethau
+
+# LOCALIZATION NOTE (outline.noFileSelected): Outline text when there are no files selected
+outline.noFileSelected=Heb ddewis ffeil
+
+# LOCALIZATION NOTE (sources.search): Sources left sidebar prompt
+# e.g. Cmd+P to search. On a mac, we use the command unicode character.
+# On windows, it's ctrl.
+sources.search=%S i chwilio
+
+# LOCALIZATION NOTE (watchExpressions.header): Watch Expressions right sidebar
+# pane header.
+watchExpressions.header=Mynegiadau Gwylio
+
+# LOCALIZATION NOTE (watchExpressions.refreshButton): Watch Expressions header
+# button for refreshing the expressions.
+watchExpressions.refreshButton=Adnewyddu
+
+# LOCALIZATION NOTE (welcome.search): The center pane welcome panel's
+# search prompt. e.g. cmd+p to search for files. On windows, it's ctrl, on
+# a mac we use the unicode character.
+welcome.search=%S i chwilio am ffeiliau
+
+# LOCALIZATION NOTE (welcome.search2): The center pane welcome panel's
+# search prompt. e.g. cmd+p to search for files. On windows, it's ctrl, on
+# a mac we use the unicode character.
+welcome.search2=%S Mynd i ffeil
+
+# LOCALIZATION NOTE (welcome.findInFiles): The center pane welcome panel's
+# search prompt. e.g. cmd+f to search for files. On windows, it's ctrl+shift+f, on
+# a mac we use the unicode character.
+welcome.findInFiles=%S i ganfod mewn ffeiliau
+
+# LOCALIZATION NOTE (welcome.findInFiles2): The center pane welcome panel's
+# search prompt. e.g. cmd+f to search for files. On windows, it's ctrl+shift+f, on
+# a mac we use the unicode character.
+welcome.findInFiles2=%S Canfod mewn ffeil
+
+# LOCALIZATION NOTE (welcome.allShortcuts): The label to open the modal of
+# shortcuts, displayed in the welcome panel.
+welcome.allShortcuts=Dangos pob llwybr byr
+
+# LOCALIZATION NOTE (sourceSearch.search): The center pane Source Search
+# prompt for searching for files.
+sourceSearch.search=Chwilio'r Ffynonellau…
+
+# LOCALIZATION NOTE (sourceSearch.search2): The center pane Source Search
+# prompt for searching for files.
+sourceSearch.search2=Mynd i ffeil…
+
+# LOCALIZATION NOTE (pauseOnExceptions): The pause on exceptions button tooltip
+# when the debugger will pause on all exceptions.
+pauseOnExceptions=Oedi ar yr holl eithriadau. Cliciwch i anwybyddu eithriadau
+
+# LOCALIZATION NOTE (loadingText): The text that is displayed in the script
+# editor when the loading process has started but there is no file to display
+# yet.
+loadingText=Llwytho…
+
+# LOCALIZATION NOTE (wasmIsNotAvailable): The text that is displayed in the
+# script editor when the WebAssembly source is not available.
+wasmIsNotAvailable=Adnewyddwch i ddadfygio'r modiwl hwn
+
+# LOCALIZATION NOTE (errorLoadingText3): The text that is displayed in the debugger
+# viewer when there is an error loading a file
+errorLoadingText3=Gwall wrth lwytho'r URI: %S
+
+# LOCALIZATION NOTE(gotoLineModal.placeholder): The placeholder
+# text displayed when the user searches for specific lines in a file
+gotoLineModal.placeholder=Mynd i linell…
+
+# LOCALIZATION NOTE(gotoLineModal.title): The message shown to users
+# to open the go to line modal
+gotoLineModal.title=Mynd i rif llinell mewn ffeil
+
+# LOCALIZATION NOTE(gotoLineModal.key3): The shortcut for opening the
+# go to line modal
+# Do not localize "Ctrl+G", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+gotoLineModal.key3=Ctrl+G
+
+# LOCALIZATION NOTE(symbolSearch.search.functionsPlaceholder): The placeholder
+# text displayed when the user searches for functions in a file
+symbolSearch.search.functionsPlaceholder=Swyddogaethau chwilio…
+symbolSearch.search.functionsPlaceholder.title=Chwilio am swyddogaeth mewn ffeil
+
+# LOCALIZATION NOTE(symbolSearch.search.variablesPlaceholder): The placeholder
+# text displayed when the user searches for variables in a file
+symbolSearch.search.variablesPlaceholder=Amrywiolion chwilio…
+symbolSearch.search.variablesPlaceholder.title=Chwilio am amrywiolyn mewn ffeil
+
+# LOCALIZATION NOTE(symbolSearch.search.key2): The Key Shortcut for
+# searching for a function or variable
+# Do not localize "CmdOrCtrl+Shift+O", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+symbolSearch.search.key2=CmdOrCtrl+Shift+O
+
+# LOCALIZATION NOTE(symbolSearch.searchModifier.modifiersLabel): A label
+# preceding the group of modifiers
+symbolSearch.searchModifier.modifiersLabel=Addaswyr:
+
+# LOCALIZATION NOTE(symbolSearch.searchModifier.regex): A search option
+# when searching text in a file
+symbolSearch.searchModifier.regex=Regex
+
+# LOCALIZATION NOTE(symbolSearch.searchModifier.caseSensitive): A search option
+# when searching text in a file
+symbolSearch.searchModifier.caseSensitive=Llythrennau mawr/bach o bwys
+
+# LOCALIZATION NOTE(symbolSearch.searchModifier.wholeWord): A search option
+# when searching text in a file
+symbolSearch.searchModifier.wholeWord=Gair Cyfan
+
+experimental=Mae hon yn nodwedd arbrofol
+
+# LOCALIZATION NOTE (whyPaused.debuggerStatement): The text that is displayed
+# in a info block explaining how the debugger is currently paused due to a `debugger`
+# statement in the code
+whyPaused.debuggerStatement=Oedwyd ar ddatganiad dadfygiwr
+
+# LOCALIZATION NOTE (whyPaused.breakpoint): The text that is displayed
+# in a info block explaining how the debugger is currently paused on a breakpoint
+whyPaused.breakpoint=Oedwyd ar dorbwynt
+
+# LOCALIZATION NOTE (whyPaused.eventBreakpoint): The text that is displayed
+# in a info block explaining how the debugger is currently paused on an event
+# breakpoint.
+whyPaused.eventBreakpoint=Oedwyd ar dorbwynt digwyddiad
+
+# LOCALIZATION NOTE (whyPaused.exception): The text that is displayed
+# in a info block explaining how the debugger is currently paused on an exception
+whyPaused.exception=Oedwyd ar eithriad
+
+# LOCALIZATION NOTE (whyPaused.mutationBreakpoint): The text that is displayed
+# in a info block explaining how the debugger is currently paused on a
+# DOM mutation breakpoint
+whyPaused.mutationBreakpoint=Oedwyd ar mudiad DOM
+
+# LOCALIZATION NOTE (whyPaused.mutationBreakpointAdded): The text that
+# is displayed to describe an added node which triggers a subtree modification
+whyPaused.mutationBreakpointAdded=Ychwanegwyd:
+
+# LOCALIZATION NOTE (whyPaused.mutationBreakpointRemoved): The text that
+# is displayed to describe a removed node which triggers a subtree modification
+whyPaused.mutationBreakpointRemoved=Tynnwyd:
+
+# LOCALIZATION NOTE (whyPaused.interrupted): The text that is displayed
+# in a info block explaining how the debugger is currently paused at
+# a JS execution
+whyPaused.interrupted=Oedwyd ar ei Weithredu
+
+# LOCALIZATION NOTE (whyPaused.resumeLimit): The text that is displayed
+# in a info block explaining how the debugger is currently paused while stepping
+# in or out of the stack
+whyPaused.resumeLimit=Oedwyd tra'n stepio
+
+# LOCALIZATION NOTE (whyPaused.pauseOnDOMEvents): The text that is displayed
+# in a info block explaining how the debugger is currently paused on a
+# dom event
+whyPaused.pauseOnDOMEvents=Oedwyd ar wrandawr digwyddiad
+
+# LOCALIZATION NOTE (whyPaused.breakpointConditionThrown): The text that is displayed
+# in an info block when evaluating a conditional breakpoint throws an error
+whyPaused.breakpointConditionThrown=Gwall gyda torbwynt amodol
+
+# LOCALIZATION NOTE (whyPaused.XHR): The text that is displayed
+# in a info block explaining how the debugger is currently paused on an
+# xml http request
+whyPaused.XHR=Oedwyd ar XMLHttpRequest
+
+# LOCALIZATION NOTE (whyPaused.promiseRejection): The text that is displayed
+# in a info block explaining how the debugger is currently paused on a
+# promise rejection
+whyPaused.promiseRejection=Oedwyd ar wrthodiad addewid
+
+# LOCALIZATION NOTE (whyPaused.getWatchpoint): The text that is displayed
+# in a info block explaining how the debugger is currently paused at a
+# watchpoint on an object property
+whyPaused.getWatchpoint=Wedi'i oedi ar fynediad i briodoledd
+
+# LOCALIZATION NOTE (whyPaused.setWatchpoint): The text that is displayed
+# in an info block explaining how the debugger is currently paused at a
+# watchpoint on an object property
+whyPaused.setWatchpoint=Wedi'i oedi ar briodwedd set
+
+# LOCALIZATION NOTE (whyPaused.assert): The text that is displayed
+# in a info block explaining how the debugger is currently paused on an
+# assert
+whyPaused.assert=Oedwyd ar honiad
+
+# LOCALIZATION NOTE (whyPaused.debugCommand): The text that is displayed
+# in a info block explaining how the debugger is currently paused on a
+# debugger statement
+whyPaused.debugCommand=Oedwyd ar swyddogaeth dadfygio
+
+# LOCALIZATION NOTE (whyPaused.other): The text that is displayed
+# in a info block explaining how the debugger is currently paused on an event
+# listener breakpoint set
+whyPaused.other=Oedwyd y dadfygiwr
+
+# LOCALIZATION NOTE (ctrl): The text that is used for documenting
+# keyboard shortcuts that use the control key
+ctrl=Ctrl
+
+# LOCALIZATION NOTE (anonymousFunction): this string is used to display
+# JavaScript functions that have no given name - they are said to be
+# anonymous.
+anonymousFunction=<anhysbys>
+
+# LOCALIZATION NOTE (stacktrace.asyncStack): this string is used to
+# indicate that a given stack frame has an async parent.
+# %S is the "Async Cause" of the frame.
+stacktrace.asyncStack=(Async: %S)
+
+# LOCALIZATION NOTE (shortcuts.toggleBreakpoint): text describing
+# keyboard shortcut action for toggling breakpoint
+shortcuts.toggleBreakpoint=Toglo'r Torbwynt
+shortcuts.toggleBreakpoint.accesskey=T
+
+# LOCALIZATION NOTE (shortcuts.toggleCondPanel.breakpoint): text describing
+# keyboard shortcut action for toggling conditional panel for breakpoints
+shortcuts.toggleCondPanel.breakpoint=Golygu Torbwyntiau Amodol
+
+# LOCALIZATION NOTE (shortcuts.toggleCondPanel.logPoint): text describing
+# keyboard shortcut action for toggling conditional panel for log points
+shortcuts.toggleCondPanel.logPoint=Golygu'r Mewngofnod
+
+# LOCALIZATION NOTE (shortcuts.pauseOrResume): text describing
+# keyboard shortcut action for pause of resume
+shortcuts.pauseOrResume=Oedi/Ailgychwyn
+
+# LOCALIZATION NOTE (shortcuts.stepOver): text describing
+# keyboard shortcut action for stepping over
+shortcuts.stepOver=Camu Dros
+
+# LOCALIZATION NOTE (shortcuts.stepIn): text describing
+# keyboard shortcut action for stepping in
+shortcuts.stepIn=Camu i Mewn
+
+# LOCALIZATION NOTE (shortcuts.stepOut): text describing
+# keyboard shortcut action for stepping out
+shortcuts.stepOut=Camu Allan
+
+# LOCALIZATION NOTE (shortcuts.fileSearch): text describing
+# keyboard shortcut action for source file search
+shortcuts.fileSearch=Chwilio Ffynhonnell y Ffeil
+
+# LOCALIZATION NOTE (shortcuts.fileSearch2): text describing
+# keyboard shortcut action for source file search
+shortcuts.fileSearch2=Mynd i ffeil
+
+# LOCALIZATION NOTE (shortcuts.gotoLine): text describing
+# keyboard shortcut for jumping to a specific line
+shortcuts.gotoLine=Mynd i linell
+
+# LOCALIZATION NOTE (shortcuts.searchAgain): text describing
+# keyboard shortcut action for searching again
+shortcuts.searchAgain=Chwilio Eto
+
+# LOCALIZATION NOTE (shortcuts.searchAgain2): text describing
+# keyboard shortcut action for searching again
+shortcuts.searchAgain2=Canfod nesaf
+
+# LOCALIZATION NOTE (shortcuts.projectSearch): text describing
+# keyboard shortcut action for full project search
+shortcuts.projectSearch=Chwilio'r Holl Broject
+
+# LOCALIZATION NOTE (shortcuts.projectSearch2): text describing
+# keyboard shortcut action for full project search
+shortcuts.projectSearch2=Canfod mewn ffeiliau
+
+# LOCALIZATION NOTE (shortcuts.functionSearch): text describing
+# keyboard shortcut action for function search
+shortcuts.functionSearch=Chwilio'r Swyddogaeth
+
+# LOCALIZATION NOTE (shortcuts.functionSearch2): text describing
+# keyboard shortcut action for function search
+shortcuts.functionSearch2=Canfod swyddogaeth
+
+# LOCALIZATION NOTE (shortcuts.buttonName): text describing
+# keyboard shortcut button text
+shortcuts.buttonName=Llwybrau byr bysellfwrdd
+
+# LOCALIZATION NOTE (variablesSeparatorLabel): The text that is displayed
+# in the variables list as a separator between the name and value.
+variablesSeparatorLabel=:
+
+variablesViewOptimizedOut=(optimeiddiwyd i ffwrdd)
+variablesViewUninitialized=(heb gychwyn)
+variablesViewMissingArgs=(ddim ar gael)
+
+# LOCALIZATION NOTE (variablesDomNodeValueTooltip): The text that is displayed
+# in a tooltip on the "open in inspector" button in the the variables list for a
+# DOMNode item.
+variablesDomNodeValueTooltip=Cliciwch i ddewis nod yn yr archwiliwr
+
+# LOCALIZATION NOTE (variablesEditButtonTooltip): The text that is displayed
+# in the variables list on a getter or setter which can be edited.
+variablesEditButtonTooltip=Clicio i osod y gwerth
+
+# LOCALIZATION NOTE (variablesViewErrorStacktrace): This is the text that is
+# shown before the stack trace in an error.
+variablesViewErrorStacktrace=Stac olrhain:
+
+# LOCALIZATION NOTE (variablesViewMoreObjects): the text that is displayed
+# when you have an object preview that does not show all of the elements. At the end of the list
+# you see "N more..." in the web console output.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of remaining items in the object
+# example: 3 more…
+variablesViewMoreObjects=Dim yn rhagor…;#1 yn rhagor…;#1 yn rhagor…;#1 yn rhagor…;#1 yn rhagor…;#1 yn rhagor…
+
+# LOCALIZATION NOTE (variablesEditableNameTooltip): The text that is displayed
+# in the variables list on an item with an editable name.
+variablesEditableNameTooltip=Clic dwbl i olygu
+
+# LOCALIZATION NOTE (variablesEditableValueTooltip): The text that is displayed
+# in the variables list on an item with an editable value.
+variablesEditableValueTooltip=Clic i newid gwerth
+
+# LOCALIZATION NOTE (variablesCloseButtonTooltip): The text that is displayed
+# in the variables list on an item which can be removed.
+variablesCloseButtonTooltip=Cliciwch i'w dynnu
+
+# LOCALIZATION NOTE (configurable|...|Tooltip): The text that is displayed
+# in the variables list on certain variables or properties as tooltips.
+# Explanations of what these represent can be found at the following links:
+# https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
+# https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/isExtensible
+# https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/isFrozen
+# https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object/isSealed
+# It's probably best to keep these in English.
+configurableTooltip=ffurfwedadwy
+enumerableTooltip=rhifadwy
+writableTooltip=ysgrifenadwy
+frozenTooltip=wedi'i rhewi
+sealedTooltip=wedi'i selio
+extensibleTooltip=estynadwy
+overriddenTooltip=gwrthwnaed
+WebIDLTooltip=WebIDL
+
+# LOCALIZATION NOTE (serviceWorkerInfo.parsed): State displayed for a service
+# worker that has been parsed.
+serviceWorkerInfo.parsed=dosranwyd
+# LOCALIZATION NOTE (serviceWorkerInfo.installing): State displayed for a
+# service worker that is being installed.
+serviceWorkerInfo.installing=Yn gosod
+# LOCALIZATION NOTE (serviceWorkerInfo.installed): State displayed for a
+# service worker that has finished being installed.
+serviceWorkerInfo.installed=Wedi'i osod
+# LOCALIZATION NOTE (serviceWorkerInfo.activating): State displayed for a
+# service worker that is being activated.
+serviceWorkerInfo.activating=gweithredu
+# LOCALIZATION NOTE (serviceWorkerInfo.activated): State displayed for a
+# service worker that has finished being activated.
+serviceWorkerInfo.activated=wedi'i weithredu
+# LOCALIZATION NOTE (serviceWorkerInfo.redundant): State displayed for a
+# service worker that is redundant.
+serviceWorkerInfo.redundant=diangen
+# LOCALIZATION NOTE (serviceWorkerInfo.unknown): State displayed for a
+# service worker that is in an unknown state.
+serviceWorkerInfo.unknown=anhysbys
diff --git a/l10n-cy/devtools/client/device.properties b/l10n-cy/devtools/client/device.properties
new file mode 100644
index 0000000000..54e2685722
--- /dev/null
+++ b/l10n-cy/devtools/client/device.properties
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside Device Emulation developer
+# tools. The correct localization of this file might be to keep it in English,
+# or another language commonly spoken among web developers.  You want to make
+# that choice consistent across the developer tools.  A good criteria is the
+# language in which you'd find the best documentation on web development on the
+# web.
+
+# LOCALIZATION NOTE:
+# These strings are category names in a list of devices that a user can choose
+# to simulate (e.g. "ZTE Open C", "VIA Vixen", "720p HD Television", etc).
+device.phones=Ffonau
+device.tablets=Tabledi
+device.laptops=Gliniaduron
+device.televisions=Teledu
+device.consoles=Consolau gemau
+device.watches=Gwylfeydd
diff --git a/l10n-cy/devtools/client/dom.properties b/l10n-cy/devtools/client/dom.properties
new file mode 100644
index 0000000000..7d9e217960
--- /dev/null
+++ b/l10n-cy/devtools/client/dom.properties
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the DOM panel
+# which is available from the Web Developer sub-menu -> 'DOM'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (dom.filterDOMPanel): A placeholder text used for
+# DOM panel search box.
+dom.filterDOMPanel=Hidlo Panel DOM
+
+# LOCALIZATION NOTE (dom.refresh): A label for Refresh button in
+# DOM panel toolbar
+dom.refresh=Adnewyddu
diff --git a/l10n-cy/devtools/client/filterwidget.properties b/l10n-cy/devtools/client/filterwidget.properties
new file mode 100644
index 0000000000..236dfe41db
--- /dev/null
+++ b/l10n-cy/devtools/client/filterwidget.properties
@@ -0,0 +1,59 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used in the CSS Filter Editor Widget
+# which can be found in a tooltip that appears in the Rule View when clicking
+# on a filter swatch displayed next to CSS declarations like 'filter: blur(2px)'.
+
+# LOCALIZATION NOTE (emptyFilterList):
+# This string is displayed when filter's list is empty
+# (no filter specified / all removed)
+emptyFilterList=Heb bennu hidl
+
+# LOCALIZATION NOTE (emptyPresetList):
+# This string is displayed when preset's list is empty
+emptyPresetList=Nid oes gennych rhagosodion wedi eu cadw. Gallwch gadw rhagosodion hidl drwy ddewis enw a'u cadw. Mae rhagosodion ar gael yn hwylus ac mae modd eu defnyddio'n rhwydd.
+
+# LOCALIZATION NOTE (addUsingList):
+# This string is displayed under [emptyFilterList] when filter's
+# list is empty, guiding user to add a filter using the list below it
+addUsingList=Ychwanegwch hidl gan ddefnyddio'r rhestr isod
+
+# LOCALIZATION NOTE (dropShadowPlaceholder):
+# This string is used as a placeholder for drop-shadow's input
+# in the filter list (shown when <input> is empty)
+dropShadowPlaceholder=lliw radiws x y
+
+# LOCALIZATION NOTE (dragHandleTooltipText):
+# This string is used as a tooltip text (shown on mouse hover) on the
+# drag handles of filters which are used to re-order filters
+dragHandleTooltipText=Llusgwch i fyny neu i lawr i ad-drefnu'r hidl
+
+# LOCALIZATION NOTE (labelDragTooltipText):
+# This string is used as a tooltip text (shown on mouse hover) on the
+# filters' labels which can be dragged left/right to increase/decrease
+# the filter's value (like photoshop)
+labelDragTooltipText=Llusgwch i'r dde neu i'r chwith i leihau neu gynyddu'r gwerth
+
+# LOCALIZATION NOTE (filterListSelectPlaceholder):
+# This string is used as a preview option in the list of possible filters
+# <select>
+filterListSelectPlaceholder=Dewis Hidl
+
+# LOCALIZATION NOTE (addNewFilterButton):
+# This string is displayed on a button used to add new filters
+addNewFilterButton=Ychwanegu
+
+# LOCALIZATION NOTE (newPresetPlaceholder):
+# This string is used as a placeholder in the list of presets which is used to
+# save a new preset
+newPresetPlaceholder=Enw'r Rhagosod
+
+# LOCALIZATION NOTE (savePresetButton):
+# This string is displayed on a button used to save a new preset
+savePresetButton=Cadw
+
+# LOCALIZATION NOTE(presetsToggleButton):
+# This string is used in a button which toggles the presets list
+presetsToggleButton=Rhagosodiadau
diff --git a/l10n-cy/devtools/client/font-inspector.properties b/l10n-cy/devtools/client/font-inspector.properties
new file mode 100644
index 0000000000..c67803bd4d
--- /dev/null
+++ b/l10n-cy/devtools/client/font-inspector.properties
@@ -0,0 +1,69 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE This file contains the Font Inspector strings.
+# The Font Inspector is a panel accessible in the Inspector sidebar.
+
+# LOCALIZATION NOTE (fontinspector.system) This label indicates that the font is a local
+# system font.
+fontinspector.system=system
+
+# LOCALIZATION NOTE (fontinspector.noFontsUsedOnCurrentElement): This label is shown when
+# no fonts were used on the selected element.
+fontinspector.noFontsUsedOnCurrentElement=Dim ffontiau'n cael eu defnyddio ar yr elfen gyfredol.
+
+# LOCALIZATION NOTE (fontinspector.copyURL): This is the text that appears in a tooltip
+# displayed when the user hovers over the copy icon next to the font URL.
+# Clicking the copy icon copies the full font URL to the user's clipboard
+fontinspector.copyURL=Copïo URL
+
+# LOCALIZATION NOTE (fontinspector.customInstanceName): Think of instances as presets
+# (groups of settings that apply in bulk to a thing). Instances have names. When the user
+# creates a new instance, it doesn't have a name. This is the text that appears as the
+# default name for a new instance. It shows up in a dropdown from which users can select
+# between predefined instances and this custom instance.
+fontinspector.customInstanceName=Cyfaddasu
+
+# LOCALIZATION NOTE (fontinspector.fontInstanceLabel): This label is shown next to the UI
+# in the font editor which allows a user to select a font instance option from a
+# dropdown. An instance is like a preset. A "font instance" is the term used by the font
+# authors to mean a group of predefined font settings.
+fontinspector.fontInstanceLabel=Enghraifft
+
+# LOCALIZATION NOTE (fontinspector.fontSizeLabel): This label is shown next to the UI
+# in the font editor which allows the user to change the font size.
+fontinspector.fontSizeLabel=Maint
+
+# LOCALIZATION NOTE (fontinspector.fontWeightLabel): This label is shown next to the UI
+# in the font editor which allows the user to change the font weight.
+fontinspector.fontWeightLabel=Pwysau
+
+# LOCALIZATION NOTE (fontinspector.fontItalicLabel): This label is shown next to the UI
+# in the font editor which allows the user to change the style of the font to italic.
+fontinspector.fontItalicLabel=Italig
+
+# LOCALIZATION NOTE (fontinspector.showMore): Label for a collapsed list of fonts.
+fontinspector.showMore=Dangos rhagor
+
+# LOCALIZATION NOTE (fontinspector.showLess): Label for an expanded list of fonts.
+fontinspector.showLess=Dangos llai
+
+# LOCALIZATION NOTE (fontinspector.letterSpacingLabel): Label for the UI to change the
+# letter spacing in the font editor.
+fontinspector.letterSpacingLabel=Bylchu
+
+# LOCALIZATION NOTE (fontinspector.lineHeightLabelCapitalized): Label for the UI to change the line height in the font editor.
+fontinspector.lineHeightLabelCapitalized=Uchder Llinell
+
+# LOCALIZATION NOTE (fontinspector.allFontsOnPageHeader): Header for the section listing
+# all the fonts on the current page.
+fontinspector.allFontsOnPageHeader=Holl ffontiau ar dudalen
+
+# LOCALIZATION NOTE (fontinspector.fontsUsedLabel): Label for the Font Editor section
+# which shows the fonts used on the selected element.
+fontinspector.fontsUsedLabel=Ffontiau'n cael eu Defnyddio
+
+# LOCALIZATION NOTE (fontinspector.previewTextPlaceholder): Placeholder for the input
+# where the user can type text to get a preview of it using a font.
+fontinspector.previewTextPlaceholder=Testun rhagolwg ffont
diff --git a/l10n-cy/devtools/client/graphs.properties b/l10n-cy/devtools/client/graphs.properties
new file mode 100644
index 0000000000..cc8c1bb529
--- /dev/null
+++ b/l10n-cy/devtools/client/graphs.properties
@@ -0,0 +1,24 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Performance Tools
+# which is available from the Web Developer sub-menu -> 'Performance'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web. These strings
+# are specifically for marker names in the performance tool.
+
+# LOCALIZATION NOTE (graphs.label.average):
+# This string is displayed on graphs when showing an average.
+graphs.label.average=cyf
+
+# LOCALIZATION NOTE (graphs.label.minimum):
+# This string is displayed on graphs when showing a minimum.
+graphs.label.minimum=llei
+
+# LOCALIZATION NOTE (graphs.label.maximum):
+# This string is displayed on graphs when showing a maximum.
+graphs.label.maximum=mwy
diff --git a/l10n-cy/devtools/client/har.properties b/l10n-cy/devtools/client/har.properties
new file mode 100644
index 0000000000..3ec33f2bae
--- /dev/null
+++ b/l10n-cy/devtools/client/har.properties
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Network Monitor
+# which is available from the Web Developer sub-menu -> 'Network Monitor'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (har.responseBodyNotIncluded): A label used within
+# HAR file explaining that HTTP response bodies are not includes
+# in exported data.
+har.responseBodyNotIncluded=Nid yw cyrff ymateb wedi eu cynnwys.
+
+# LOCALIZATION NOTE (har.responseBodyNotIncluded): A label used within
+# HAR file explaining that HTTP request bodies are not includes
+# in exported data.
+har.requestBodyNotIncluded=Nid yw cyrff ymateb wedi eu cynnwys.
+
diff --git a/l10n-cy/devtools/client/inspector.properties b/l10n-cy/devtools/client/inspector.properties
new file mode 100644
index 0000000000..4dae99c537
--- /dev/null
+++ b/l10n-cy/devtools/client/inspector.properties
@@ -0,0 +1,557 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Inspector
+# which is available from the Web Developer sub-menu -> 'Inspect'.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+inspector.panelLabel.markupView=Golwg Nodi
+
+# LOCALIZATION NOTE (markupView.more.showing)
+# When there are too many nodes to load at once, we will offer to
+# show all the nodes.
+markupView.more.showing=Roedd rhai nodau wedi eu cuddio.
+
+# LOCALIZATION NOTE (markupView.more.showAll2): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+markupView.more.showAll2=Dangos dim un o'r nodau;Dangos pob un o'r #1 nod;Dangos pob un o'r #1 nod;Dangos pob un o'r #1 nod;Dangos pob un o'r #1 nod;Dangos pob un o'r #1 nod
+
+# LOCALIZATION NOTE (markupView.whitespaceOnly.label)
+# Used in the badge that appears when whitespace-only text nodes are displayed in the
+# inspector.
+markupView.whitespaceOnly.label=bwlch gwyn
+
+# LOCALIZATION NOTE (markupView.whitespaceOnly)
+# Used in a tooltip that appears when the user hovers over whitespace-only text nodes in
+# the inspector. %S in the content will be replaced by the whitespace characters used in
+# the text node.
+markupView.whitespaceOnly=Nod testun bwlch gwyn yn unig: %S
+
+# LOCALIZATION NOTE (markupView.display.flex.tooltiptext2)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.flex.tooltiptext2=Mae'r elfen hon yn ymddwyn fel elfen bloc ac yn gosod ei chynnwys yn ôl y model flexbox. Cliciwch i doglo'r troshaen flexbox ar gyfer yr elfen hon.
+
+# LOCALIZATION NOTE (markupView.display.inlineFlex.tooltiptext2)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.inlineFlex.tooltiptext2=Mae'r elfen hon yn ymddwyn fel elfen bloc ac yn gosod ei chynnwys yn ôl y model flexbox. Cliciwch i doglo'r troshaen flexbox ar gyfer yr elfen hon.
+
+# LOCALIZATION NOTE (markupView.display.grid.tooltiptext2)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.grid.tooltiptext2=Mae'r elfen hon yn ymddwyn fel elfen bloc ac yn gosod ei chynnwys yn ôl y model grid. Cliciwch i doglo'r troshaen grid ar gyfer yr elfen hon.
+
+# LOCALIZATION NOTE (markupView.display.inlineGrid.tooltiptext2)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.inlineGrid.tooltiptext2=Mae'r elfen hon yn ymddwyn fel elfen bloc ac yn gosod ei chynnwys yn ôl y model grid. Cliciwch i doglo'r troshaen grid ar gyfer yr elfen hon.
+
+# LOCALIZATION NOTE (markupView.display.subgrid.tooltiptext)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.subgrid.tooltiptiptext=Mae'r elfen hon yn gosod alla ei chyd-destun yn ôl model y grid ond yn ildio'r diffiniad i'w resi a/neu golofnau i'w gynhwysydd grid rhiant.
+
+# LOCALIZATION NOTE (markupView.display.flowRoot.tooltiptext)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.flowRoot.tooltiptext=Mae'r elfen hon yn creu blwch elfen bloc sy'n sefydlu cyd-destun fformat bloc newydd.
+
+# LOCALIZATION NOTE (markupView.display.contents.tooltiptext2)
+# Used in a tooltip that appears when the user hovers over the display type button in
+# the markup view.
+markupView.display.contents.tooltiptext2=Nid yw'r elfen hon yn cynhyrchu blwch penodol ei hun, ond yn llunio ei gynnwys.
+
+# LOCALIZATION NOTE (markupView.event.tooltiptext)
+# Used in a tooltip that appears when the user hovers over 'event' badge in
+# the markup view.
+markupView.event.tooltiptext=Gwrandawyr digwyddiadau
+
+# LOCALIZATION NOTE (markupView.custom.tooltiptext)
+# Used in a tooltip that appears when the user hovers over 'custom' badge in
+# the markup view. Only displayed on custom elements with a shadow root attached.
+markupView.custom.tooltiptext=Dangos diffiniad elfen cyfaddas
+
+# LOCALIZATION NOTE (markupView.newAttribute.label)
+# This is used to speak the New Attribute button when editing a tag
+# and a screen reader user tabs to it. This string is not visible onscreen.
+markupView.newAttribute.label=Priodoledd newydd
+
+# LOCALIZATION NOTE (markupView.revealLink.tooltip)
+# Used as a tooltip for an icon in the markup view when displaying elements inserted in
+# <slot> nodes in a custom  component. When clicking on the icon, the corresponding
+# non-slotted container will be selected
+markupView.revealLink.tooltip=Datgelu
+
+#LOCALIZATION NOTE: Used in the image preview tooltip when the image could not be loaded
+previewTooltip.image.brokenImage=Methu llwytho'r ddelwedd
+
+# LOCALIZATION NOTE: Used in color picker tooltip when the eyedropper is disabled for
+# non-HTML documents
+eyedropper.disabled.title=Ddim ar gael ar ddogfennau sydd ddim yn HTML
+
+#LOCALIZATION NOTE: Used in the event tooltip to allow the debugger to be opened
+eventsTooltip.openInDebugger=Agor yn y Dadfygiwr
+
+#LOCALIZATION NOTE: Used in the event tooltip when a script's filename cannot be detected
+eventsTooltip.unknownLocation=Lleoliad anhysbys
+
+#LOCALIZATION NOTE: Used in the mouseover tooltip when hovering "Unknown location."
+eventsTooltip.unknownLocationExplanation=Nid oes modd canfod lleoliad gwreiddiol y gwrandawr hwn. Efallai fod y cod wedi ei drawsbilio gan wasanaeth fel Babel.
+
+#LOCALIZATION NOTE: Used in the tooltip for Bubbling
+eventsTooltip.Bubbling=Swigodi
+
+#LOCALIZATION NOTE: Used in the tooltip for Capturing
+eventsTooltip.Capturing=Cipio
+
+# LOCALIZATION NOTE (allTabsMenuButton.tooltip): The tooltip that gets
+# displayed when hovering over the tabs overflow button.
+allTabsMenuButton.tooltip=Dangos pob tab
+
+# LOCALIZATION NOTE (inspector.showThreePaneMode): This is the tooltip for the button
+# that toggles on the 3 pane inspector mode.
+inspector.showThreePaneMode=Toglo cychwyn yr archwiliwr 3 paen
+
+# LOCALIZATION NOTE (inspector.hideThreePaneMode): This is the tooltip for the button
+# that toggles off the 3 pane inspector mode.
+inspector.hideThreePaneMode=Toglo diffodd yr archwiliwr 3 paen
+
+# LOCALIZATION NOTE (inspector.searchResultsCount2): This is the label that
+# will show up next to the inspector search box. %1$S is the current result
+# index and %2$S is the total number of search results. For example: "3 of 9".
+# This won't be visible until the search box is updated in Bug 835896.
+inspector.searchResultsCount2=%1$S o %2$S
+
+# LOCALIZATION NOTE (inspector.searchResultsNone): This is the label that
+# will show up next to the inspector search box when no matches were found
+# for the given string.
+# This won't be visible until the search box is updated in Bug 835896.
+inspector.searchResultsNone=Dim cydweddu
+
+# LOCALIZATION NOTE (inspector.menu.openUrlInNewTab.label): This is the label of
+# a menu item in the inspector contextual-menu that appears when the user right-
+# clicks on the attribute of a node in the inspector that is a URL, and that
+# allows to open that URL in a new tab.
+inspector.menu.openUrlInNewTab.label=Agor Dolen mewn Tab Newydd
+
+# LOCALIZATION NOTE (inspector.menu.copyUrlToClipboard.label): This is the label
+# of a menu item in the inspector contextual-menu that appears when the user
+# right-clicks on the attribute of a node in the inspector that is a URL, and
+# that allows to copy that URL in the clipboard.
+inspector.menu.copyUrlToClipboard.label=Copïo Cyfeiriad Dolen
+
+# LOCALIZATION NOTE (inspector.menu.selectElement.label): This is the label of a
+# menu item in the inspector contextual-menu that appears when the user right-
+# clicks on the attribute of a node in the inspector that is the ID of another
+# element in the DOM (like with <label for="input-id">), and that allows to
+# select that element in the inspector.
+inspector.menu.selectElement.label=Dewis Elfen #%S
+
+# LOCALIZATION NOTE (inspectorEditAttribute.label): This is the label of a
+# sub-menu "Attribute" in the inspector contextual-menu that appears
+# when the user right-clicks on the node in the inspector, and that allows
+# to edit an attribute on this node.
+inspectorEditAttribute.label=Golygu Priodoledd “%S”
+inspectorEditAttribute.accesskey=G
+
+# LOCALIZATION NOTE (inspectorRemoveAttribute.label): This is the label of a
+# sub-menu "Attribute" in the inspector contextual-menu that appears
+# when the user right-clicks on the attribute of a node in the inspector,
+# and that allows to remove this attribute.
+inspectorRemoveAttribute.label=Tynnu Priodoledd “%S”
+inspectorRemoveAttribute.accesskey=T
+
+# LOCALIZATION NOTE (inspectorCopyAttributeValue.label): This is the label of a
+# sub-menu "Attribute" in the inspector contextual-menu that appears
+# when the user right-clicks on the attribute of a node in the inspector,
+# and that allows to copy the attribute value to clipboard.
+inspectorCopyAttributeValue.label=Copïo Gwerth Priodoledd “%S”
+inspectorCopyAttributeValue.accesskey=G
+
+# LOCALIZATION NOTE (inspector.nodePreview.highlightNodeLabel):
+# This string is displayed in a tooltip that is shown when hovering over a the
+# inspector icon displayed next to a DOM node preview (e.g. next to something
+# like "div#foo.bar").
+# DOM node previews can be displayed in places like the animation-inspector, the
+# console or the object inspector.
+# The tooltip invites the user to click on the icon in order to highlight the
+# node in the page.
+inspector.nodePreview.highlightNodeLabel=Cliciwch i amlygu'r nod ar y dudalen
+
+# LOCALIZATION NOTE (inspectorHTMLEdit.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users edit the
+# (outer) HTML of the current node
+inspectorHTMLEdit.label=Golygu fel HTML
+inspectorHTMLEdit.accesskey=G
+
+# LOCALIZATION NOTE (inspectorCopyInnerHTML.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users copy the
+# inner HTML of the current node
+inspectorCopyInnerHTML.label=HTML Mewnol
+inspectorCopyInnerHTML.accesskey=H
+
+# LOCALIZATION NOTE (inspectorCopyOuterHTML.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users copy the
+# outer HTML of the current node
+inspectorCopyOuterHTML.label=HTML Allanol
+inspectorCopyOuterHTML.accesskey=A
+
+# LOCALIZATION NOTE (inspectorCopyCSSSelector.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users copy
+# the CSS Selector of the current node
+inspectorCopyCSSSelector.label=Dewisydd CSS
+inspectorCopyCSSSelector.accesskey=S
+
+# LOCALIZATION NOTE (inspectorCopyCSSPath.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users copy
+# the full CSS path of the current node
+inspectorCopyCSSPath.label=Llwybr CSS
+inspectorCopyCSSPath.accesskey=L
+
+# LOCALIZATION NOTE (inspectorCopyXPath.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users copy
+# the XPath of the current node
+inspectorCopyXPath.label=XPath
+inspectorCopyXPath.accesskey=X
+
+# LOCALIZATION NOTE (inspectorPasteOuterHTML.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users paste outer
+# HTML in the current node
+inspectorPasteOuterHTML.label=HTML Allanol
+inspectorPasteOuterHTML.accesskey=A
+
+# LOCALIZATION NOTE (inspectorPasteInnerHTML.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users paste inner
+# HTML in the current node
+inspectorPasteInnerHTML.label=HTML Mewnol
+inspectorPasteInnerHTML.accesskey=H
+
+# LOCALIZATION NOTE (inspectorHTMLPasteBefore.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users paste
+# the HTML before the current node
+inspectorHTMLPasteBefore.label=Cyn
+inspectorHTMLPasteBefore.accesskey=C
+
+# LOCALIZATION NOTE (inspectorHTMLPasteAfter.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users paste
+# the HTML after the current node
+inspectorHTMLPasteAfter.label=Wedi
+inspectorHTMLPasteAfter.accesskey=W
+
+# LOCALIZATION NOTE (inspectorHTMLPasteFirstChild.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users paste
+# the HTML as the first child the current node
+inspectorHTMLPasteFirstChild.label=Fel y Plentyn Cyntaf
+inspectorHTMLPasteFirstChild.accesskey=C
+
+# LOCALIZATION NOTE (inspectorHTMLPasteLastChild.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users paste
+# the HTML as the last child the current node
+inspectorHTMLPasteLastChild.label=Fel y Plentyn Olaf
+inspectorHTMLPasteLastChild.accesskey=O
+
+# LOCALIZATION NOTE (inspectorScrollNodeIntoView.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users scroll
+# the current node into view
+inspectorScrollNodeIntoView.label=Sgrolio i Golwg
+inspectorScrollNodeIntoView.accesskey=S
+
+# LOCALIZATION NOTE (inspectorHTMLDelete.label): This is the label shown in
+# the inspector contextual-menu for the item that lets users delete the
+# current node
+inspectorHTMLDelete.label=Dileu Nod
+inspectorHTMLDelete.accesskey=D
+
+# LOCALIZATION NOTE (inspectorAttributesSubmenu.label): This is the label
+# shown in the inspector contextual-menu for the sub-menu of the other
+# attribute items, which allow to:
+# - add new attribute
+# - edit attribute
+# - remove attribute
+inspectorAttributesSubmenu.label=Priodweddau
+inspectorAttributesSubmenu.accesskey=P
+
+# LOCALIZATION NOTE (inspectorAddAttribute.label): This is the label shown in
+# the inspector contextual-menu for the item that lets users add attribute
+# to current node
+inspectorAddAttribute.label=Ychwanegu Priodwedd
+inspectorAddAttribute.accesskey=Y
+
+# LOCALIZATION NOTE (inspectorPseudoClassSubmenu.label): This is the label
+# shown in the inspector contextual-menu for the sub-menu of the pseudo-classes.
+inspectorPseudoClassSubmenu.label=Newid dosbarth ffug
+
+# LOCALIZATION NOTE (inspectorBreakpointSubmenu.label): This is the label
+# shown in the inspector contextual-menu for the sub-menu of the DOM breakpoints.
+inspectorBreakpointSubmenu.label=Torri ar…
+
+# LOCALIZATION NOTE (inspectorSubtreeModification.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users add a DOM breakpoint
+# for subtree modification.
+inspectorSubtreeModification.label=Newid Isgoeden
+
+# LOCALIZATION NOTE (inspectorAttributeModification.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users add a DOM breakpoint
+# for attribute modification.
+inspectorAttributeModification.label=Newid Priodoledd
+
+# LOCALIZATION NOTE (inspectorNodeRemoval.label): This is the label shown
+# in the inspector contextual-menu for the item that lets users add a DOM breakpoint
+# for node removal.
+inspectorNodeRemoval.label=Tynnu Nod
+
+# LOCALIZATION NOTE (inspectorSearchHTML.label3): This is the label that is
+# shown as the placeholder for the markup view search in the inspector.
+inspectorSearchHTML.label3=Chwilio HTML
+
+# LOCALIZATION NOTE (inspectorImageDataUri.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users copy
+# the URL embedding the image data encoded in Base 64 (what we name
+# here Image Data URL). For more information:
+# https://developer.mozilla.org/en-US/docs/Web/HTTP/data_URIs
+inspectorImageDataUri.label=Delwedd Data-URL
+
+# LOCALIZATION NOTE (inspectorShowDOMProperties.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users see
+# the DOM properties of the current node. When triggered, this item
+# opens the split Console and displays the properties in its side panel.
+inspectorShowDOMProperties.label=Dangos Priodoleddau DOM
+
+# LOCALIZATION NOTE (inspectorShowAccessibilityProperties.label): This is the
+# label shown in the inspector contextual-menu for the item that lets users see
+# the accessibility tree and accessibility properties of the current node.
+# When triggered, this item opens accessibility panel and selects an accessible
+# object for the given node.
+inspectorShowAccessibilityProperties.label=Dangos Priodoleddau Hygyrchedd
+
+# LOCALIZATION NOTE (inspectorUseInConsole.label): This is the label
+# shown in the inspector contextual-menu for the item that outputs a
+# variable for the current node to the console. When triggered,
+# this item opens the split Console.
+inspectorUseInConsole.label=Defnyddio yn y Consol
+
+# LOCALIZATION NOTE (inspectorExpandNode.label): This is the label
+# shown in the inspector contextual-menu for recursively expanding
+# mark-up elements
+inspectorExpandNode.label=Ehangu Popeth
+
+# LOCALIZATION NOTE (inspectorCollapseAll.label): This is the label
+# shown in the inspector contextual-menu for recursively collapsing
+# mark-up elements
+inspectorCollapseAll.label=Cau Popeth
+
+# LOCALIZATION NOTE (inspectorScreenshotNode.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users take
+# a screenshot of the currently selected node.
+inspectorScreenshotNode.label=Nod Llun Sgrin
+
+# LOCALIZATION NOTE (inspectorDuplicateNode.label): This is the label
+# shown in the inspector contextual-menu for the item that lets users
+# duplicate the currently selected node.
+inspectorDuplicateNode.label=Nod Dyblyg
+
+# LOCALIZATION NOTE (inspectorAddNode.label): This is the label shown in
+# the inspector toolbar for the button that lets users add elements to the
+# DOM (as children of the currently selected element).
+inspectorAddNode.label=Creu Nod Newydd
+inspectorAddNode.accesskey=C
+
+# LOCALIZATION NOTE (inspectorCopyHTMLSubmenu.label): This is the label
+# shown in the inspector contextual-menu for the sub-menu of the other
+# copy items, which allow to:
+# - Copy Inner HTML
+# - Copy Outer HTML
+# - Copy Unique selector
+# - Copy Image data URI
+inspectorCopyHTMLSubmenu.label=Copïo
+
+# LOCALIZATION NOTE (inspectorPasteHTMLSubmenu.label): This is the label
+# shown in the inspector contextual-menu for the sub-menu of the other
+# paste items, which allow to:
+# - Paste Inner HTML
+# - Paste Outer HTML
+# - Before
+# - After
+# - As First Child
+# - As Last Child
+inspectorPasteHTMLSubmenu.label=Gludo
+
+# LOCALIZATION NOTE (inspectorCustomElementDefinition.label): This is the label
+# shown in the inspector contextual-menu for custom elements to which a shadow root has
+# been attached. Clicking on the menu item will open the Debugger on the custom element
+# definition location.
+inspectorCustomElementDefinition.label=Dangos Elfen Gyfaddas
+
+# LOCALIZATION NOTE (inspector.searchHTML.key):
+# Key shortcut used to focus the DOM element search box on top-right corner of
+# the markup view
+inspector.searchHTML.key=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (markupView.hide.key):
+# Key shortcut used to hide the selected node in the markup view.
+markupView.hide.key=h
+
+# LOCALIZATION NOTE (markupView.edit.key):
+# Key shortcut used to hide the selected node in the markup view.
+markupView.edit.key=F2
+
+# LOCALIZATION NOTE (markupView.scrollInto.key):
+# Key shortcut used to scroll the webpage in order to ensure the selected node
+# is visible
+markupView.scrollInto.key=s
+
+# LOCALIZATION NOTE (inspector.sidebar.fontInspectorTitle):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying the list of fonts used in the page.
+inspector.sidebar.fontInspectorTitle=Ffontiau
+
+# LOCALIZATION NOTE (inspector.sidebar.changesViewTitle):
+# Title of the Changes sidebar tab shown in the Inspector panel. The Changes panel shows
+# style changes made using DevTools.
+inspector.sidebar.changesViewTitle=Newidiadau
+
+# LOCALIZATION NOTE (inspector.sidebar.ruleViewTitle):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying the list of CSS rules used
+# in the page.
+inspector.sidebar.ruleViewTitle=Rheolau
+
+# LOCALIZATION NOTE (inspector.sidebar.computedViewTitle):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying the list of computed CSS values
+# used in the page.
+inspector.sidebar.computedViewTitle=Cyfrifwyd
+
+# LOCALIZATION NOTE (inspector.sidebar.layoutViewTitle2):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying layout information defined in the page.
+inspector.sidebar.layoutViewTitle2=Cynllun
+
+# LOCALIZATION NOTE (inspector.sidebar.animationInspectorTitle):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying animations defined in the page.
+inspector.sidebar.animationInspectorTitle=Animeiddiadau
+
+# LOCALIZATION NOTE (inspector.sidebar.compatibilityViewTitle):
+# This is the title shown in a tab in the side panel of the Inspector panel
+# that corresponds to the tool displaying web compatibility information about the page.
+inspector.sidebar.compatibilityViewTitle=Cydnawsedd
+
+# LOCALIZATION NOTE (inspector.eyedropper.label): A string displayed as the tooltip of
+# a button in the inspector which toggles the Eyedropper tool
+inspector.eyedropper.label=Cipio lliw o'r dudalen
+
+# LOCALIZATION NOTE (inspector.breadcrumbs.label): A string visible only to a screen reader and
+# is used to label (using aria-label attribute) a container for inspector breadcrumbs
+inspector.breadcrumbs.label=Briwsion
+
+# LOCALIZATION NOTE (inspector.browserStyles.label): This is the label for the checkbox
+# that specifies whether the styles that are not from the user's stylesheet should be
+# displayed or not.
+inspector.browserStyles.label=Arddulliau porwr
+
+# LOCALIZATION NOTE (inspector.filterStyles.placeholder): This is the placeholder that
+# goes in the search box when no search term has been entered.
+inspector.filterStyles.placeholder=Arddulliau Hidlau
+
+# LOCALIZATION NOTE (inspector.addRule.tooltip): This is the tooltip shown when
+# hovering the `Add new rule` button in the rules view toolbar. This should
+# match ruleView.contextmenu.addNewRule in styleinspector.properties
+inspector.addRule.tooltip=Ychwanegu rheol newydd
+
+# LOCALIZATION NOTE (inspector.togglePseudo.tooltip): This is the tooltip
+# shown when hovering over the `Toggle Pseudo Class Panel` button in the
+# rule view toolbar.
+inspector.togglePseudo.tooltip=Toglo dosbarthiadau ffug
+
+# LOCALIZATION NOTE (inspector.classPanel.toggleClass.tooltip): This is the tooltip
+# shown when hovering over the `Toggle Class Panel` button in the
+# rule view toolbar.
+inspector.classPanel.toggleClass.tooltip=Toglo'r dosbarthiadau
+
+# LOCALIZATION NOTE (inspector.classPanel.newClass.placeholder): This is the placeholder
+# shown inside the text field used to add a new class in the rule-view.
+inspector.classPanel.newClass.placeholder=Ychwanegu dosbarth newydd
+
+# LOCALIZATION NOTE (inspector.classPanel.noClasses): This is the text displayed in the
+# class panel when the current element has no classes applied.
+inspector.classPanel.noClasses=Dim dosbarthiadau yn yr elfen hon
+
+# LOCALIZATION NOTE (inspector.noProperties): In the case where there are no CSS
+# properties to display e.g. due to search criteria this message is
+# displayed.
+inspector.noProperties=Heb ganfod priodweddau CSS.
+
+# LOCALIZATION NOTE (inspector.printSimulation.tooltip):
+# This is the tooltip of the print simulation button in the Rule View toolbar
+# that toggles print simulation.
+inspector.printSimulation.tooltip = Toggle efelychu cyfryngau print ar gyfer y dudalen
+
+# LOCALIZATION NOTE (inspector.colorSchemeSimulation.tooltip):
+# This is the tooltip of the color scheme simulation button in the Rule View
+# toolbar that toggles color scheme simulation.
+inspector.colorSchemeSimulation.tooltip=Toglo efelychiad cynllun lliw'r dudalen
+
+# LOCALIZATION NOTE (markupView.scrollableBadge.label): This is the text displayed inside a
+# badge, in the inspector, next to nodes that are scrollable in the page.
+markupView.scrollableBadge.label=sgrolio
+
+# LOCALIZATION NOTE (markupView.scrollableBadge.tooltip): This is the tooltip that is displayed
+# when hovering over badges next to scrollable elements in the inspector.
+markupView.scrollableBadge.tooltip=Mae gan yr elfen hon troslifo sgrolio.
+
+# LOCALIZATION NOTE (markupView.scrollableBadge.interactive.tooltip): This is the tooltip that is displayed
+# when hovering over interactive badges next to scrollable elements in the inspector.
+markupView.scrollableBadge.interactive.tooltip=Mae gan yr elfen hon orlif sgroliadwy. Cliciwch i ddatgelu elfennau sy'n achosi'r gorlif.
+
+# LOCALIZATION NOTE (markupView.overflowBadge.label): This is the text displayed inside a
+# badge, in the inspector, next to nodes that are causing overflow in other elements.
+markupView.overflowBadge.label=gorlif
+
+# LOCALIZATION NOTE (markupView.overflowBadge.tooltip): This is the tooltip that is displayed
+# when hovering over badges next to overflow causing elements in the inspector.
+markupView.overflowBadge.tooltip=Mae'r elfen hon yn achosi i elfen orlifo.
+
+# LOCALIZATION NOTE (rulePreviewTooltip.noAssociatedRule): This is the text displayed inside
+# the RulePreviewTooltip when a rule cannot be found for a CSS property declaration.
+rulePreviewTooltip.noAssociatedRule=Dim rheol gysylltiedig
+
+# LOCALIZATION NOTE (colorPickerTooltip.contrastAgainstBgTitle): A title text for the
+# contrast ratio value description that labels the background the color contrast ratio is calculated
+# against, used together with the actual background color. %S in the content will be replaced by a
+# span (containing bg color swatch) and textNode (containing bg color hex string) at run time
+colorPickerTooltip.contrastAgainstBgTitle=Cyfrifwyd yn erbyn y cefndir: %S
+
+# LOCALIZATION NOTE (colorPickerTooltip.spectrumDraggerTitle): A title text for the
+# spectrum dragger panel in the color picker tooltip.
+colorPickerTooltip.spectrumDraggerTitle=Sbectrwm
+
+# LOCALIZATION NOTE (colorPickerTooltip.eyedropperTitle): A title text for the
+# eyedropper in the color picker tooltip.
+colorPickerTooltip.eyedropperTitle=Dewiswch liw ar y dudalen
+
+# LOCALIZATION NOTE (colorPickerTooltip.colorNameTitle): A title text for the
+# closest color name shown in the color picker tooltip, used together with the actual color.
+# %S in the content will be replaced by the color name the current color is closest to.
+colorPickerTooltip.colorNameTitle=Yr agosaf at: %S
+
+# LOCALIZATION NOTE (colorPickerTooltip.hueSliderTitle): A title text for the
+# hue slider in the color picker tooltip.
+colorPickerTooltip.hueSliderTitle=Arlliw
+
+# LOCALIZATION NOTE (colorPickerTooltip.alphaSliderTitle): A title text for the
+# alpha slider in the color picker tooltip.
+colorPickerTooltip.alphaSliderTitle=Didreiddedd
+
+# LOCALIZATION NOTE (colorPickerTooltip.contrast.large.title): A title text for the color
+# contrast ratio description in the color picker tooltip, used together with the specification
+# that the color contrast criteria used is for large text. %S in the content will be replaced by a
+# large text indicator span at run time.
+colorPickerTooltip.contrast.large.title=Cydraniad %S:
diff --git a/l10n-cy/devtools/client/jit-optimizations.properties b/l10n-cy/devtools/client/jit-optimizations.properties
new file mode 100644
index 0000000000..f00a32b0d1
--- /dev/null
+++ b/l10n-cy/devtools/client/jit-optimizations.properties
@@ -0,0 +1,35 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used within the JIT tools
+# in the Performance Tools which is available from the Web Developer
+# sub-menu -> 'Performance' The correct localization of this file might
+# be to keep it in English, or another language commonly spoken among
+# web developers. You want to make that choice consistent across the
+# developer tools. A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (jit.title):
+# This string is displayed in the header of the JIT Optimizations view.
+jit.title=Optimeiddiadau JIT
+
+# LOCALIZATION NOTE (jit.optimizationFailure):
+# This string is displayed in a tooltip when no JIT optimizations were detected.
+jit.optimizationFailure=Methodd yr optimeiddio
+
+# LOCALIZATION NOTE (jit.samples):
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This string is displayed for the unit representing the number of times a
+# frame is sampled.
+# "#1" represents the number of samples
+# example: 30 samples
+jit.samples=Dim samplau;#1 sampl;#1 sampl;#1 sampl;#1 sampl;#1 sampl
+
+# LOCALIZATION NOTE (jit.types):
+# This string is displayed for the group of Ion Types in the optimizations view.
+jit.types=Mathau
+
+# LOCALIZATION NOTE (jit.attempts):
+# This string is displayed for the group of optimization attempts in the optimizations view.
+jit.attempts=Ceisiadau
diff --git a/l10n-cy/devtools/client/jsonview.properties b/l10n-cy/devtools/client/jsonview.properties
new file mode 100644
index 0000000000..651eedea18
--- /dev/null
+++ b/l10n-cy/devtools/client/jsonview.properties
@@ -0,0 +1,47 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used in the JSON View tool
+# that is used to inspect application/json document types loaded
+# in the browser.
+
+# LOCALIZATION NOTE The correct localization of this file might be to keep it
+# in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best documentation
+# on web development on the web.
+
+# LOCALIZATION NOTE (jsonViewer.tab.JSON, jsonViewer.tab.RawData,
+# jsonViewer.tab.Headers): Label for a panel tab.
+jsonViewer.tab.JSON=JSON
+jsonViewer.tab.RawData=Data Bras
+jsonViewer.tab.Headers=Penynnau
+
+# LOCALIZATION NOTE (jsonViewer.responseHeaders, jsonViewer.requestHeaders):
+# Label for header groups within the 'Headers' panel.
+jsonViewer.responseHeaders=Pennyn Ymateb
+jsonViewer.requestHeaders=Pennyn Gofyn
+
+# LOCALIZATION NOTE (jsonViewer.Save): Label for save command
+jsonViewer.Save=Cadw
+
+# LOCALIZATION NOTE (jsonViewer.Copy): Label for clipboard copy command
+jsonViewer.Copy=Copïo
+
+# LOCALIZATION NOTE (jsonViewer.ExpandAll): Label for expanding all nodes
+jsonViewer.ExpandAll=Ehangu Popeth
+
+jsonViewer.ExpandAllSlow=Ehangu Pawb (araf)
+
+# LOCALIZATION NOTE (jsonViewer.CollapseAll): Label for collapsing all nodes
+jsonViewer.CollapseAll=Cau Popeth
+
+# LOCALIZATION NOTE (jsonViewer.PrettyPrint): Label for JSON
+# pretty print action button.
+jsonViewer.PrettyPrint=Argraffu Del
+
+# LOCALIZATION NOTE (jsonViewer.filterJSON): Label used in search box
+# at the top right cornder of the JSON Viewer.
+jsonViewer.filterJSON=Hidl JSON
+
diff --git a/l10n-cy/devtools/client/layout.properties b/l10n-cy/devtools/client/layout.properties
new file mode 100644
index 0000000000..9194afba42
--- /dev/null
+++ b/l10n-cy/devtools/client/layout.properties
@@ -0,0 +1,129 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE This file contains the Layout Inspector strings.
+# The Layout Inspector is a panel accessible in the Inspector sidebar.
+
+# LOCALIZATION NOTE (flexbox.header): The accordion header for the Flexbox panel when
+# no flex container or item is selected.
+flexbox.header=Flexbox
+
+# LOCALIZATION NOTE (flexbox.backButtonLabel): The spoken label for the button
+# that returns from the display of a flex item to the flex item list.
+# This label is spoken by screen readers, not displayed on screen.
+flexbox.backButtonLabel=Nôl i Gynhwysydd Flex
+
+# LOCALIZATION (flexbox.flexContainer): The accordion header for the Flexbox panel
+# when a flex container is selected.
+flexbox.flexContainer=Cynhwysydd Flex
+
+# LOCALIZATION NOTE) (flexbox.flexItemOf): The accordion header for the Flexbox panel
+# when a flex item is selected. %s represents the flex container selector.
+flexbox.flexItemOf=Eitem Flex %S
+
+# LOCALIZATION NOTE (flexbox.noFlexboxeOnThisPage): In the case where there are no CSS
+# flex containers to display.
+flexbox.noFlexboxeOnThisPage=Dewiswch gynhwysydd neu eitem Flex i barhau.
+
+# LOCALIZATION NOTE (flexbox.flexItems): Header label displayed for the flex item list.
+flexbox.flexItems=Eitemau Flex
+
+# LOCALIZATION NOTE (flexbox.noFlexItems): Label shown in the flex items list section if
+# there are no flex items for the flex container to display.
+flexbox.noFlexItems=Dim eitemau flex
+
+# LOCALIZATION NOTE (flexbox.itemSizing.baseSizeSectionHeader): Header label displayed
+# at the start of the flex item sizing Base Size section.
+flexbox.itemSizing.baseSizeSectionHeader=Maint y Sail
+
+# LOCALIZATION NOTE (flexbox.itemSizing.flexibilitySectionHeader): Header label displayed
+# at the start of the flex item sizing Flexibility section.
+flexbox.itemSizing.flexibilitySectionHeader=Hyblygrwydd
+
+# LOCALIZATION NOTE (flexbox.itemSizing.minSizeSectionHeader): Header label displayed
+# at the start of the flex item sizing Minimum Size section.
+flexbox.itemSizing.minSizeSectionHeader=Lleiafswm Maint
+
+# LOCALIZATION NOTE (flexbox.itemSizing.maxSizeSectionHeader): Header label displayed at
+# the start of the flex item sizing Maximum Size section.
+flexbox.itemSizing.maxSizeSectionHeader=Lleiafswm Maint
+
+# LOCALIZATION NOTE (flexbox.itemSizing.finalSizeSectionHeader): Header label displayed at
+# the start of the flex item sizing Final Size section.
+flexbox.itemSizing.finalSizeSectionHeader=Maint Trefynnol
+
+# LOCALIZATION NOTE (flexbox.itemSizing.itemContentSize): Label shown in the flex item
+# sizing panel. It tells users that a given item’s base size was calculated from its
+# content size when unconstrained.
+flexbox.itemSizing.itemContentSize=Maint Cynnwys
+
+# LOCALIZATION NOTE (flexbox.itemSizing.clampedToMax): Label shown in the flexbox item
+# sizing panel. It tells users that a given item attempted to grow but ended up being
+# clamped to a smaller max size.
+# (Note that clamp is a common word in flexbox terminology. It refers to constraining an
+# item's size to some defined min/max-width/height set on the element, even though there
+# might have been room for it to grow, or reason for it to shrink more).
+flexbox.itemSizing.clampedToMax=Clampiwyd yr eitem i'w maint llawn.
+
+# LOCALIZATION NOTE (flexbox.itemSizing.clampedToMin): Label shown in the flexbox item
+# sizing panel. It tells users that a given item attempted to grow but ended up being
+# clamped to a larger min size.
+# (Note that clamp is a common word in flexbox terminology. It refers to constraining an
+# item's size to some defined min/max-width/height set on the element, even though there
+# might have been room for it to grow, or reason for it to shrink more).
+flexbox.itemSizing.clampedToMin=Clampiwyd yr eitem i'w lleiafswm maint.
+
+# LOCALIZATION NOTE (flexbox.itemSizing.setToGrow): Label shown in the flex item sizing
+# panel. It tells users that a given item was set to grow.
+flexbox.itemSizing.setToGrow=Roedd yr eitem ar fin tyfu.
+
+# LOCALIZATION NOTE (flexbox.itemSizing.setToShrink): Label shown in the flexbox item
+# sizing panel. It tells users that a given item was set to shrink.
+flexbox.itemSizing.setToShrink=Roedd yr eitem ar fin crebachu.
+
+# LOCALIZATION NOTE (flexbox.itemSizing.notSetToGrow): Label shown in the
+# flexbox item sizing panel. It tells users that a given item was not set to grow, even
+# though there might have been space on the flex line for it to grow.
+flexbox.itemSizing.notSetToGrow=Nid oedd yr eitem ar fin crebachu.
+
+# LOCALIZATION NOTE (flexbox.itemSizing.notSetToShrink): Label shown in the
+# flexbox item sizing panel. It tells users that a given item did not shrink even though
+# there might not have been enough space on the flex line for all items to fit.
+flexbox.itemSizing.notSetToShrink=Nid oedd yr eitem wedi ei osod i grebachu.
+
+# LOCALIZATION NOTE (flexbox.togglesFlexboxHighlighter2): The tooltip text for the Flexbox
+# toggle button.
+flexbox.togglesFlexboxHighlighter2=Newid Amlygwr Flexbox
+
+# LOCALIZATION NOTE (layout.cannotShowGridOutline, layout.cannotSHowGridOutline.title):
+# In the case where the grid outline cannot be effectively displayed.
+layout.cannotShowGridOutline=Methu dangos amlinelliad i'r grid
+layout.cannotShowGridOutline.title=Nid oes modd ffitio'r amlinelliad grid o fewn panel y cyllun iddo fod yn ddefnyddiol.
+
+# LOCALIZATION NOTE (layout.displayAreaNames): Label of the display area names setting
+# option in the CSS Grid panel.
+layout.displayAreaNames=Enwau'r maes dangos
+
+# LOCALIZATION NOTE (layout.displayLineNumbers): Label of the display line numbers
+# setting option in the CSS Grid panel.
+layout.displayLineNumbers=Dangos rhifau llinellau
+
+# LOCALIZATION NOTE (layout.extendLinesInfinitely): Label of the extend lines
+# infinitely setting option in the CSS Grid panel.
+layout.extendLinesInfinitely=Estyn llinellau'n ddiderfyn
+
+# LOCALIZATION NOTE (layout.header): The accordion header for the CSS Grid panel.
+layout.header=Grid
+
+# LOCALIZATION NOTE (layout.gridDisplaySettings): The header for the grid display
+# settings container in the CSS Grid panel.
+layout.gridDisplaySettings=Gosodiadau Dangos Grid
+
+# LOCALIZATION NOTE (layout.noGridsOnThisPage): In the case where there are no CSS grid
+# containers to display.
+layout.noGridsOnThisPage=Nid yw Grid CSS y cael ei ddefnyddio ar y dudalen hon
+
+# LOCALIZATION NOTE (layout.overlayGrid): Alternate header for the list of grid container
+# elements if only one item can be selected.
+layout.overlayGrid=Grid Troshaen
diff --git a/l10n-cy/devtools/client/markers.properties b/l10n-cy/devtools/client/markers.properties
new file mode 100644
index 0000000000..26e69644b6
--- /dev/null
+++ b/l10n-cy/devtools/client/markers.properties
@@ -0,0 +1,139 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Performance Tools
+# which is available from the Web Developer sub-menu -> 'Performance'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web. These strings
+# are specifically for marker names in the performance tool.
+
+# LOCALIZATION NOTE (marker.label.*):
+# These strings are displayed in the Performance Tool waterfall, identifying markers.
+# We want to use the same wording as Google Chrome when appropriate.
+marker.label.styles=Ail-gyfrifo'r Arddull
+marker.label.stylesApplyChanges=Gosod Newidiadau Arddull
+marker.label.reflow=Cynllun
+marker.label.paint=Paent
+marker.label.composite=Haenau Cyfansawdd
+marker.label.compositeForwardTransaction=Anfonwyd Cais Cyfansawdd
+marker.label.javascript=Galwad Swyddogaeth
+marker.label.parseHTML=Didoli HTML
+marker.label.parseXML=Didoli XML
+marker.label.domevent=Digwyddiad DOM
+marker.label.consoleTime=Consol
+marker.label.garbageCollection2=Casglu Sbwriel
+marker.label.garbageCollection.incremental=GC Cynnyddol
+marker.label.garbageCollection.nonIncremental=GC anghynyddol
+marker.label.minorGC=GC Bach
+marker.label.cycleCollection=Casgliad Cylchol
+marker.label.cycleCollection.forgetSkippable=Lleihad Graff CC
+marker.label.timestamp=Stamp Amser
+marker.label.worker=Gweithwyr
+marker.label.messagePort=MessagePort
+marker.label.unknown=Anhysbys
+
+# LOCALIZATION NOTE (marker.label.javascript.*):
+# These strings are displayed as JavaScript markers that have special
+# reasons that can be translated.
+marker.label.javascript.scriptElement=Tag Sgript
+marker.label.javascript.promiseCallback=Adalw Addewid
+marker.label.javascript.promiseInit=Cychwyn Addewid
+marker.label.javascript.workerRunnable=Gweithwyr
+marker.label.javascript.jsURI=URI JavaScript
+marker.label.javascript.eventHandler=Triniwr Digwyddiad
+
+# LOCALIZATION NOTE (marker.field.*):
+# Strings used in the waterfall sidebar as property names.
+
+# General marker fields
+marker.field.start=Cychwyn:
+marker.field.end=Diwedd:
+marker.field.duration=Hyd:
+
+# General "reason" for a marker (JavaScript, Garbage Collection)
+marker.field.causeName=Achos:
+# General "type" for a marker (Cycle Collection, Garbage Collection)
+marker.field.type=Math:
+# General "label" for a marker (user defined)
+marker.field.label=Label:
+
+# Field names for stack values
+marker.field.stack=Stac:
+marker.field.startStack=Stacio ar y cychwyn:
+marker.field.endStack=Stacio ar y diwedd:
+
+# %S is the "Async Cause" of a marker, and this signifies that the cause
+# was an asynchronous one in a displayed stack.
+marker.field.asyncStack=(Async: %S)
+
+# For console.time markers
+marker.field.consoleTimerName=Enw'r Amserydd:
+
+# For DOM Event markers
+marker.field.DOMEventType=Math o Ddigwyddiad:
+marker.field.DOMEventPhase=Cyfnod:
+
+# Non-incremental cause for a Garbage Collection marker
+marker.field.nonIncrementalCause=Cymal Anghynyddol:
+
+# For "Recalculate Style" markers
+marker.field.isAnimationOnly=Animeiddio'n Unig:
+
+# The type of operation performed by a Worker.
+marker.worker.serializeDataOffMainThread=Cyfresu data mewn Gweithiwr
+marker.worker.serializeDataOnMainThread=Cyfresu data yn y prif edefyn
+marker.worker.deserializeDataOffMainThread=Dadgyfresu data yn y Gweithiwr
+marker.worker.deserializeDataOnMainThread=Dadgyfresu data ar y prif edefyn
+
+# The type of operation performed by a MessagePort
+marker.messagePort.serializeData=Cyfresoli data
+marker.messagePort.deserializeData=Dadgyfresoli data
+
+# Strings used in the waterfall sidebar as values.
+marker.value.unknownFrame=<lleoliadau anhysbys>
+marker.value.DOMEventTargetPhase=Targed
+marker.value.DOMEventCapturingPhase=Cipio
+marker.value.DOMEventBubblingPhase=Byrlymu
+
+# LOCALIZATION NOTE (marker.gcreason.label.*):
+# These strings are used to give a concise but readable description of a GC reason.
+marker.gcreason.label.API=Galwad API
+marker.gcreason.label.EAGER_ALLOC_TRIGGER=Triger Dynodi Awyddus
+marker.gcreason.label.DESTROY_RUNTIME=Diffodd
+marker.gcreason.label.LAST_DITCH=Dim Cof ar Ôl
+marker.gcreason.label.TOO_MUCH_MALLOC=Gormod o Feitiau Wedi eu Dynodi
+marker.gcreason.label.ALLOC_TRIGGER=Gormod o Ddyraniadau
+marker.gcreason.label.DEBUG_GC=Dadfygio GC
+marker.gcreason.label.COMPARTMENT_REVIVED=Adfer y Marw Cyffredinol
+marker.gcreason.label.RESET=Gorffen Cylch Cynyddol
+marker.gcreason.label.OUT_OF_NURSERY=Meithrinfa'n Llawn
+marker.gcreason.label.EVICT_NURSERY=Dadfeddiant Meithrin
+marker.gcreason.label.FULL_STORE_BUFFER=Gwrthrychau Meithrin yn Rhy Weithgar
+marker.gcreason.label.SHARED_MEMORY_LIMIT=Methodd y Dynodiad Mawr
+marker.gcreason.label.PERIODIC_FULL_GC=GC Cyfnodol yn Llawn
+marker.gcreason.label.INCREMENTAL_TOO_SLOW=Graddfa Dynodi'n Rhy Gyflym
+marker.gcreason.label.COMPONENT_UTILS=Cu.forceGC
+marker.gcreason.label.MEM_PRESSURE=Cof yn Isel
+marker.gcreason.label.CC_WAITING=Gorfodwyd gan Gasglu Cylchol
+marker.gcreason.label.CC_FINISHED=Gorffennwyd y Casgliad Cylchol
+marker.gcreason.label.CC_FORCED=Gorfodwyd gan Gasglu Cylchol
+marker.gcreason.label.LOAD_END=Gorffennwyd Llwytho'r Dudalen
+marker.gcreason.label.PAGE_HIDE=Symudwyd i'r Cefndir
+marker.gcreason.label.NSJSCONTEXT_DESTROY=Dinistrio Cyd-destun JS
+marker.gcreason.label.SET_NEW_DOCUMENT=Dogfen Newydd
+marker.gcreason.label.SET_DOC_SHELL=Dogfen Newydd
+marker.gcreason.label.DOM_UTILS=Galwad API
+marker.gcreason.label.DOM_IPC=IPC
+marker.gcreason.label.DOM_WORKER=GC Gweithiwr Cyfnodol
+marker.gcreason.label.INTER_SLICE_GC=Sleisen Cynyddol Cyfnodol GC
+marker.gcreason.label.FULL_GC_TIMER=GC Cyfnodol yn Llawn
+marker.gcreason.label.SHUTDOWN_CC=Diffodd
+marker.gcreason.label.DOM_WINDOW_UTILS=Defnyddiwr Anweithredol
+marker.gcreason.label.USER_INACTIVE=Defnyddiwr Anweithredol
+
+# The name of a nursery collection.
+marker.nurseryCollection=Casgliad Meithrin
diff --git a/l10n-cy/devtools/client/memory.properties b/l10n-cy/devtools/client/memory.properties
new file mode 100644
index 0000000000..1416e9191f
--- /dev/null
+++ b/l10n-cy/devtools/client/memory.properties
@@ -0,0 +1,426 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Memory Tools
+# which is available from the Web Developer sub-menu -> 'Memory'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (snapshot.io.save): The label for the link that saves a
+# snapshot to disk.
+snapshot.io.save=Cadw
+
+# LOCALIZATION NOTE (snapshot.io.delete): The label for the link that deletes
+# a snapshot
+snapshot.io.delete=Dileu
+
+# LOCALIZATION NOTE (snapshot.io.save.window): The title for the window
+# displayed when saving a snapshot to disk.
+snapshot.io.save.window=Cymryd Ciplun
+
+# LOCALIZATION NOTE (snapshot.io.import.window): The title for the window
+# displayed when importing a snapshot form disk.
+snapshot.io.import.window=Mewnforio Ciplun
+
+# LOCALIZATION NOTE (snapshot.io.filter): The title for the filter used to
+# filter file types (*.fxsnapshot)
+snapshot.io.filter=Cipluniau Firefox
+
+# LOCALIZATION NOTE (aggregate.mb): The label annotating the number of bytes (in
+# megabytes) in a snapshot. %S represents the value, rounded to 2 decimal
+# points.
+aggregate.mb=%S MB
+
+# LOCALIZATION NOTE (snapshot-title.loading): The title for a snapshot before
+# it has a creation time to display.
+snapshot-title.loading=Prosesu…
+
+# LOCALIZATION NOTE (checkbox.recordAllocationStacks): The label describing the
+# boolean checkbox whether or not to record call stacks.
+checkbox.recordAllocationStacks=Cofnodi galwadau stac
+
+# LOCALIZATION NOTE (checkbox.recordAllocationStacks.tooltip): The tooltip for
+# the label describing the boolean checkbox whether or not to record call
+# stacks.
+checkbox.recordAllocationStacks.tooltip=Toglwch y recordiad o'r alwad pentwr o pan gafodd y gwrthrych ei ddyrannu. Bydd cipluniau dilynol yn gallu grwpio a labelu gwrthrychau drwy staciau galwad, ond dim ond gyda rhai gwrthrychau a grëwyd ar ôl toglo'r dewis hwn. Mae staciau galwadau yn achosi traul ar y perfformaid.
+
+# LOCALIZATION NOTE (toolbar.displayBy): The label describing the select menu
+# options of the display options.
+toolbar.displayBy=Grwpio yn ôl:
+
+# LOCALIZATION NOTE (toolbar.displayBy.tooltip): The tooltip for the label
+# describing the select menu options of the display options.
+toolbar.displayBy.tooltip=Newid sut mae gwrthrychau yn cael eu grwpio
+
+# LOCALIZATION NOTE (toolbar.pop-view): The text in the button to go back to the
+# previous view.
+toolbar.pop-view=←
+
+# LOCALIZATION NOTE (toolbar.pop-view.label): The text for the label for the
+# button to go back to the previous view.
+toolbar.pop-view.label=Nôl i'r cyfanredol
+
+# LOCALIZATION NOTE (toolbar.viewing-individuals): The text letting the user
+# know that they are viewing individual nodes from a census group.
+toolbar.viewing-individuals=⁂ Edrych ar unigolion mewn grŵp
+
+# LOCALIZATION NOTE (censusDisplays.coarseType.tooltip): The tooltip for the
+# "coarse type" display option.
+censusDisplays.coarseType.tooltip=Grwpio o eitemau yn ôl eu math
+
+# LOCALIZATION NOTE (censusDisplays.allocationStack.tooltip): The tooltip for
+# the "call stack" display option.
+censusDisplays.allocationStack.tooltip=Grwpio eitemau yn ôl y cofnod pentwr JavaScript pan gafodd y gwrthrych ei ddyrannu
+
+# LOCALIZATION NOTE (censusDisplays.invertedAllocationStack.tooltip): The
+# tooltip for the "inverted call stack" display option.
+censusDisplays.invertedAllocationStack.tooltip=Grwpio eitemau yn ôl y galwad pentwr JavaScript pan gafodd y gwrthrych ei ddyrannu
+
+# LOCALIZATION NOTE (toolbar.labelBy): The label describing the select menu
+# options of the label options.
+toolbar.labelBy=Label gan:
+
+# LOCALIZATION NOTE (toolbar.labelBy.tooltip): The tooltip for the label describing the
+# select menu options of the label options.
+toolbar.labelBy.tooltip=Newid sut mae gwrthrychau'n cael eu labelu
+
+# LOCALIZATION NOTE (dominatorTreeDisplays.coarseType.tooltip): The tooltip for
+# the "coarse type" dominator tree display option.
+dominatorTreeDisplays.coarseType.tooltip=Labelu gwrthrychau yn ôl y categorïau cyffredinol maen nhw'n ffitio iddynt
+
+# LOCALIZATION NOTE (dominatorTreeDisplays.allocationStack.tooltip): The
+# tooltip for the "call stack" dominator tree display option.
+dominatorTreeDisplays.allocationStack.tooltip=Labelu eitemau yn ôl y cofnod pentwr JavaScript pan gafodd y gwrthrych ei ddyrannu
+
+# LOCALIZATION NOTE (treeMapDisplays.coarseType.tooltip): The tooltip for
+# the "coarse type" tree map display option.
+treeMapDisplays.coarseType.tooltip=Labelu gwrthrychau yn ôl y categorïau cyffredinol maen nhw'n ffitio iddynt
+
+# LOCALIZATION NOTE (toolbar.view): The label for the view selector in the
+# toolbar.
+toolbar.view=Dangos:
+
+# LOCALIZATION NOTE (toolbar.view.tooltip): The tooltip for the label for the
+# view selector in the toolbar.
+toolbar.view.tooltip=Newid golwg y ciplun
+
+# LOCALIZATION NOTE (toolbar.view.census): The label for the census view option
+# in the toolbar.
+toolbar.view.census=Casglu
+
+# LOCALIZATION NOTE (toolbar.view.census.tooltip): The tooltip for the label for
+# the census view option in the toolbar.
+toolbar.view.census.tooltip=Gweld crynodeb o gynnwys ciplun pentwr drwy grynhoi gwrthrychau i grwpiau
+
+# LOCALIZATION NOTE (toolbar.view.dominators): The label for the dominators view
+# option in the toolbar.
+toolbar.view.dominators=Goruchafwyr
+
+# LOCALIZATION NOTE (toolbar.view.dominators.tooltip): The tooltip for the label
+# for the dominators view option in the toolbar.
+toolbar.view.dominators.tooltip=Gweld y goeden dominyddu ac arwyneb y strwythur mwyaf yn y ciplun gwres
+
+# LOCALIZATION NOTE (toolbar.view.treemap): The label for the tree map option
+# in the toolbar.
+toolbar.view.treemap=Map Coeden
+
+# LOCALIZATION NOTE (toolbar.view.treemap.tooltip): The tooltip for the label for
+# the tree map view option in the toolbar.
+toolbar.view.treemap.tooltip=Defnydd y cof gweledol: mae blociau mwy yn cyfrif fel y canran fwyaf o'r defnydd o'r cof
+
+# LOCALIZATION NOTE (take-snapshot): The label describing the button that
+# initiates taking a snapshot, either as the main label, or a tooltip.
+take-snapshot=Cymryd ciplun
+
+# LOCALIZATION NOTE (import-snapshot): The label describing the button that
+# initiates importing a snapshot.
+import-snapshot=Mewnforio…
+
+# LOCALIZATION NOTE (clear-snapshots.tooltip): The tooltip for the button that
+# deletes existing snapshot.
+clear-snapshots.tooltip=Dileu pob ciplun
+
+# LOCALIZATION NOTE (diff-snapshots.tooltip): The tooltip for the button that
+# initiates selecting two snapshots to diff with each other.
+diff-snapshots.tooltip=Cymharu cipluniau
+
+# LOCALIZATION NOTE (filter.placeholder): The placeholder text used for the
+# memory tool's filter search box.
+filter.placeholder=Hidlo
+
+# LOCALIZATION NOTE (filter.tooltip): The tooltip text used for the memory
+# tool's filter search box.
+filter.tooltip=Hidlo cynnwys y ciplun
+
+# LOCALIZATION NOTE (tree-item.view-individuals.tooltip): The tooltip for the
+# button to view individuals in this group.
+tree-item.view-individuals.tooltip=Gweld nodau unigol o'r grŵp a'u llwybrau cadw
+
+# LOCALIZATION NOTE (tree-item.load-more): The label for the links to fetch the
+# lazily loaded sub trees in the dominator tree view.
+tree-item.load-more=Llwytho rhagor…
+
+# LOCALIZATION NOTE (tree-item.rootlist): The label for the root of the
+# dominator tree.
+tree-item.rootlist=Gwreiddiau GC
+
+# LOCALIZATION NOTE (tree-item.nostack): The label describing the row in the heap tree
+# that represents a row broken down by call stack when no stack was available.
+tree-item.nostack=(dim stac i'w dangos)
+
+# LOCALIZATION NOTE (tree-item.nofilename): The label describing the row in the
+# heap tree that represents a row broken down by filename when no filename was
+# available.
+tree-item.nofilename=(dim enw ffeil ar gael)
+
+# LOCALIZATION NOTE (tree-item.root): The label describing the row in the heap tree
+# that represents the root of the tree when inverted.
+tree-item.root=(gwraidd)
+
+# LOCALIZATION NOTE (tree-item.percent2): A percent of bytes or count displayed in the tree view.
+# there are two "%" after %S to escape and display "%"
+tree-item.percent2=%S%%
+
+# LOCALIZATION NOTE (diffing.baseline): The name of the baseline snapshot in a
+# diffing comparison.
+diffing.baseline=Gwaelodlin
+
+# LOCALIZATION NOTE (diffing.comparison): The name of the snapshot being
+# compared to the baseline in a diffing comparison.
+diffing.comparison=Cymhariaeth
+
+# LOCALIZATION NOTE (diffing.prompt.selectBaseline): The prompt to select the
+# first snapshot when doing a diffing comparison.
+diffing.prompt.selectBaseline=Dewis ciplun gwaelodlin
+
+# LOCALIZATION NOTE (diffing.prompt.selectComparison): The prompt to select the
+# second snapshot when doing a diffing comparison.
+diffing.prompt.selectComparison=Dewis ciplun i'w gymharu â'r gwaelodlin
+
+# LOCALIZATION NOTE (diffing.state.error): The label describing the diffing
+# state ERROR, used in the snapshot list when an error occurs while diffing two
+# snapshots.
+diffing.state.error=Gwall
+
+# LOCALIZATION NOTE (diffing.state.error.full): The text describing the diffing
+# state ERROR, used in the main view when an error occurs while diffing two
+# snapshots.
+diffing.state.error.full=Bu gwall wrth gymharu cipluniau.
+
+# LOCALIZATION NOTE (diffing.state.taking-diff): The label describing the diffin
+# state TAKING_DIFF, used in the snapshots list when computing the difference
+# between two snapshots.
+diffing.state.taking-diff=Gwahaniaeth cyfrifiaduro…
+
+# LOCALIZATION NOTE (diffing.state.taking-diff.full): The label describing the
+# diffing state TAKING_DIFF, used in the main view when computing the difference
+# between two snapshots.
+diffing.state.taking-diff.full=Gwahaniaeth cyfrifiaduro…
+
+# LOCALIZATION NOTE (diffing.state.selecting): The label describing the diffing
+# state SELECTING.
+diffing.state.selecting=Dewis dau ciplun i'w cymharu
+
+# LOCALIZATION NOTE (diffing.state.selecting.full): The label describing the
+# diffing state SELECTING, used in the main view when selecting snapshots to
+# diff.
+diffing.state.selecting.full=Dewis dau ciplun i'w cymharu
+
+# LOCALIZATION NOTE (dominatorTree.state.computing): The label describing the
+# dominator tree state COMPUTING.
+dominatorTree.state.computing=Cynhyrchu adroddiad domineiddwyr…
+
+# LOCALIZATION NOTE (dominatorTree.state.computing.full): The label describing the
+# dominator tree state COMPUTING, used in the dominator tree view.
+dominatorTree.state.computing.full=Cynhyrchu adroddiad domineiddwyr…
+
+# LOCALIZATION NOTE (dominatorTree.state.fetching): The label describing the
+# dominator tree state FETCHING.
+dominatorTree.state.fetching=Meintiau cyfrifiadura…
+
+# LOCALIZATION NOTE (dominatorTree.state.fetching.full): The label describing the
+# dominator tree state FETCHING, used in the dominator tree view.
+dominatorTree.state.fetching.full=Cyfrifo maint cadw'r domineiddwyr…
+
+# LOCALIZATION NOTE (dominatorTree.state.incrementalFetching): The label
+# describing the dominator tree state INCREMENTAL_FETCHING.
+dominatorTree.state.incrementalFetching=Estyn…
+
+# LOCALIZATION NOTE (dominatorTree.state.incrementalFetching.full): The label describing the
+# dominator tree state INCREMENTAL_FETCHING, used in the dominator tree view.
+dominatorTree.state.incrementalFetching.full=Estyn rhagor…
+
+# LOCALIZATION NOTE (dominatorTree.state.error): The label describing the
+# dominator tree state ERROR.
+dominatorTree.state.error=Gwall
+
+# LOCALIZATION NOTE (dominatorTree.state.error.full): The label describing the
+# dominator tree state ERROR, used in the dominator tree view.
+dominatorTree.state.error.full=Bu gwall wrth brosesu'r goeden goruchafu
+
+# LOCALIZATION NOTE (snapshot.state.saving.full): The label describing the
+# snapshot state SAVING, used in the main heap view.
+snapshot.state.saving.full=Cadw ciplun…
+
+# LOCALIZATION NOTE (snapshot.state.reading.full): The label describing the
+# snapshot state READING, and SAVED, due to these states being combined
+# visually, used in the main heap view.
+snapshot.state.reading.full=Darllen y ciplun…
+
+# LOCALIZATION NOTE (snapshot.state.saving-census.full): The label describing
+# the snapshot state SAVING, used in the main heap view.
+snapshot.state.saving-census.full=Cynhyrchu adroddiad…
+
+# LOCALIZATION NOTE (snapshot.state.saving-tree-map.full): The label describing
+# the snapshot state SAVING, used in the main heap view.
+snapshot.state.saving-tree-map.full=Cadw map coeden…
+
+# LOCALIZATION NOTE (snapshot.state.error.full): The label describing the
+# snapshot state ERROR, used in the main heap view.
+snapshot.state.error.full=Bu gwall wrth brosesu'r ciplun.
+
+# LOCALIZATION NOTE (individuals.state.error): The short message displayed when
+# there is an error fetching individuals from a group.
+individuals.state.error=Gwall
+
+# LOCALIZATION NOTE (individuals.state.error.full): The longer message displayed
+# when there is an error fetching individuals from a group.
+individuals.state.error.full=Bu gwall wrth estyn unigolion yn y grŵp
+
+# LOCALIZATION NOTE (individuals.state.fetching): The short message displayed
+# while fetching individuals.
+individuals.state.fetching=Estyn…
+
+# LOCALIZATION NOTE (individuals.state.fetching.full): The longer message
+# displayed while fetching individuals.
+individuals.state.fetching.full=Estyn unigolion mewn grŵp…
+
+# LOCALIZATION NOTE (individuals.field.node): The header label for an individual
+# node.
+individuals.field.node=Nod
+
+# LOCALIZATION NOTE (individuals.field.node.tooltip): The tooltip for the header
+# label for an individual node.
+individuals.field.node.tooltip=Nod unigol mewn ciplun
+
+# LOCALIZATION NOTE (snapshot.state.saving): The label describing the snapshot
+# state SAVING, used in the snapshot list view
+snapshot.state.saving=Cadw ciplun…
+
+# LOCALIZATION NOTE (snapshot.state.importing): The label describing the
+# snapshot state IMPORTING, used in the snapshot list view
+snapshot.state.importing=Mewnforio ciplun…
+
+# LOCALIZATION NOTE (snapshot.state.reading): The label describing the snapshot
+# state READING, and SAVED, due to these states being combined visually, used in
+# the snapshot list view.
+snapshot.state.reading=Darllen y ciplun…
+
+# LOCALIZATION NOTE (snapshot.state.saving-census): The label describing the
+# snapshot state SAVING, used in snapshot list view.
+snapshot.state.saving-census=Cadw adroddiad…
+
+# LOCALIZATION NOTE (snapshot.state.saving-census): The label describing the
+# snapshot state SAVING, used in snapshot list view.
+snapshot.state.saving-tree-map=Cadw map coeden…
+
+# LOCALIZATION NOTE (snapshot.state.error): The label describing the snapshot
+# state ERROR, used in the snapshot list view.
+snapshot.state.error=Gwall
+
+# LOCALIZATION NOTE (heapview.no-difference): Message displayed when there is no
+# difference between two snapshots.
+heapview.no-difference=Dim gwahaniaeth rhwng y llinell sail a'r gymhariaeth.
+
+# LOCALIZATION NOTE (heapview.none-match): Message displayed when there are no
+# matches when filtering.
+heapview.none-match=Dim cydweddu.
+
+# LOCALIZATION NOTE (heapview.none-match): Message displayed when there report
+# is empty.
+heapview.empty=Gwag.
+
+# LOCALIZATION NOTE (heapview.noAllocationStacks): The message displayed to
+# users when selecting a display by "call stack" but no call stacks
+# were recorded in the heap snapshot.
+heapview.noAllocationStacks=Dim staciau galw i'w canfod. Cofnodwch staciau galw cyn cymryd cipluniau.
+
+# LOCALIZATION NOTE (heapview.field.retainedSize): The name of the column in the
+# dominator tree view for retained byte sizes.
+heapview.field.retainedSize=Meintiau Cadwyd (Didau)
+
+# LOCALIZATION NOTE (heapview.field.retainedSize.tooltip): The tooltip for the
+# column header in the dominator tree view for retained byte sizes.
+heapview.field.retainedSize.tooltip=Swm maint y gwrthrych ei hun, a meintiau'r holl gwrthrychau eraill sy'n cael eu cadw'n fyw drwyddo
+
+# LOCALIZATION NOTE (heapview.field.shallowSize): The name of the column in the
+# dominator tree view for shallow byte sizes.
+heapview.field.shallowSize=Meintiau Bas (Didau)
+
+# LOCALIZATION NOTE (heapview.field.shallowSize.tooltip): The tooltip for the
+# column header in the dominator tree view for shallow byte sizes.
+heapview.field.shallowSize.tooltip=Maint y gwrthrych ei hun
+
+# LOCALIZATION NOTE (dominatortree.field.label): The name of the column in the
+# dominator tree for an object's label.
+dominatortree.field.label=Dominyddwr
+
+# LOCALIZATION NOTE (dominatortree.field.label.tooltip): The tooltip for the column
+# header in the dominator tree view for an object's label.
+dominatortree.field.label.tooltip=Label ar gyfer gwrthrych yn y cof
+
+# LOCALIZATION NOTE (heapview.field.bytes): The name of the column in the heap
+# view for bytes.
+heapview.field.bytes=Beit
+
+# LOCALIZATION NOTE (heapview.field.bytes.tooltip): The tooltip for the column
+# header in the heap view for bytes.
+heapview.field.bytes.tooltip=Y nifer o ddidau sy'n cael eu defnyddio gan y grŵp hwn, ag eithrio is-grwpiau
+
+# LOCALIZATION NOTE (heapview.field.count): The name of the column in the heap
+# view for count.
+heapview.field.count=Cyfrif
+
+# LOCALIZATION NOTE (heapview.field.count.tooltip): The tooltip for the column
+# header in the heap view for count.
+heapview.field.count.tooltip=Y nifer o wrthrychau cyraeddadwy yn y grŵp hwn, ag eithrio is-grwpiau
+
+# LOCALIZATION NOTE (heapview.field.totalbytes): The name of the column in the
+# heap view for total bytes.
+heapview.field.totalbytes=Cyfanswm y Beitiau
+
+# LOCALIZATION NOTE (heapview.field.totalbytes.tooltip): The tooltip for the
+# column header in the heap view for total bytes.
+heapview.field.totalbytes.tooltip=Y nifer o ddidau sy'n cael eu defnyddio gan y grŵp hwn, gan gynnwys is-grwpiau
+
+# LOCALIZATION NOTE (heapview.field.totalcount): The name of the column in the
+# heap view for total count.
+heapview.field.totalcount=Cyfanswm
+
+# LOCALIZATION NOTE (heapview.field.totalcount.tooltip): The tooltip for the
+# column header in the heap view for total count.
+heapview.field.totalcount.tooltip=Y nifer o wrthrychau cyraeddadwy yn y grŵp hwn, gan gynnwys is-grwpiau
+
+# LOCALIZATION NOTE (heapview.field.name): The name of the column in the heap
+# view for name.
+heapview.field.name=Grŵp
+
+# LOCALIZATION NOTE (heapview.field.name.tooltip): The tooltip for the column
+# header in the heap view for name.
+heapview.field.name.tooltip=Enw'r grŵp hwn
+
+# LOCALIZATION NOTE (shortest-paths.header): The header label for the shortest
+# paths pane.
+shortest-paths.header=Llwybrau cadw (o Wraidd y Casglwr Sbwriel)
+
+# LOCALIZATION NOTE (shortest-paths.select-node): The message displayed in the
+# shortest paths pane when a node is not yet selected.
+shortest-paths.select-node=Dewiswch eitem i weld ei llwybrau cadw
+
+# LOCALIZATION NOTE (tree-map.node-count): The label for the count value of a
+# node in the tree map
+tree-map.node-count=cyfrif
diff --git a/l10n-cy/devtools/client/menus.properties b/l10n-cy/devtools/client/menus.properties
new file mode 100644
index 0000000000..341d41eb42
--- /dev/null
+++ b/l10n-cy/devtools/client/menus.properties
@@ -0,0 +1,35 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (devtoolsRemoteDebugging.label): This is the label for the menu item
+# in Tools > Web Developer. Clicking on this menu item will open about:debugging which
+# acts as a hub for debugging remote devices.
+devtoolsRemoteDebugging.label = Dadfygio Pell
+devtoolsRemoteDebugging.accesskey = P
+
+browserConsoleCmd.label = Consol y Porwr
+browserConsoleCmd.accesskey = P
+
+responsiveDesignMode.label = Modd Cynllunio Ymatebol
+responsiveDesignMode.accesskey = Y
+
+eyedropper.label = Dewisydd
+eyedropper.accesskey = D
+
+# LOCALIZATION NOTE (browserToolboxMenu.label): This is the label for the
+# application menu item that opens the browser toolbox UI in the Tools menu.
+browserToolboxMenu.label = Blwch Offer y Porwr
+browserToolboxMenu.accesskey = B
+
+# LOCALIZATION NOTE (browserContentToolboxMenu.label): This is the label for the
+# application menu item that opens the browser content toolbox UI in the Tools menu.
+# This toolbox allows to debug the chrome of the content process in multiprocess builds.
+browserContentToolboxMenu.label = Blwch Offer Cynnwys y Porwr
+browserContentToolboxMenu.accesskey = B
+
+devToolboxMenuItem.label = Offer Toglo
+devToolboxMenuItem.accesskey = O
+
+getMoreDevtoolsCmd.label = Estyn Rhagor o Offer
+getMoreDevtoolsCmd.accesskey = E
diff --git a/l10n-cy/devtools/client/netmonitor.properties b/l10n-cy/devtools/client/netmonitor.properties
new file mode 100644
index 0000000000..764d238e86
--- /dev/null
+++ b/l10n-cy/devtools/client/netmonitor.properties
@@ -0,0 +1,1539 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Network Monitor
+# which is available from the Web Developer sub-menu -> 'Network Monitor'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (netmonitor.security.state.secure)
+# This string is used as an tooltip for request that was performed over secure
+# channel i.e. the connection was encrypted.
+netmonitor.security.state.secure=Roedd y cysylltiad defnyddiwyd i estyn yr adnodd yn un diogel.
+
+# LOCALIZATION NOTE (netmonitor.security.state.insecure)
+# This string is used as an tooltip for request that was performed over insecure
+# channel i.e. the connection was not https
+netmonitor.security.state.insecure=Doedd y cysylltiad defnyddiwyd i estyn yr adnodd ddim yn un diogel.
+
+# LOCALIZATION NOTE (netmonitor.security.state.broken)
+# This string is used as an tooltip for request that failed due to security
+# issues.
+netmonitor.security.state.broken=Rhwystrodd gwall diogelwch yr adnodd rhag cael ei lwytho.
+
+# LOCALIZATION NOTE (netmonitor.security.state.weak)
+# This string is used as an tooltip for request that had minor security issues
+netmonitor.security.state.weak=Trosglwyddwyd yr adnodd dros gysylltiad sy'n defnyddio amgryptiad gwan.
+
+# LOCALIZATION NOTE (netmonitor.security.enabled):
+# This string is used to indicate that a specific security feature is used by
+# a connection in the security details tab.
+# For example: "HTTP Strict Transport Security: Enabled"
+netmonitor.security.enabled=Galluogwyd
+
+# LOCALIZATION NOTE (netmonitor.security.disabled):
+# This string is used to indicate that a specific security feature is not used by
+# a connection in the security details tab.
+# For example: "HTTP Strict Transport Security: Disabled"
+netmonitor.security.disabled=Analluogwyd
+
+# LOCALIZATION NOTE (netmonitor.security.hostHeader):
+# This string is used as a header for section containing security information
+# related to the remote host. %S is replaced with the domain name of the remote
+# host. For example: Host example.com
+netmonitor.security.hostHeader=Gwesteiwr %S:
+
+# LOCALIZATION NOTE (netmonitor.security.notAvailable):
+# This string is used to indicate that a certain piece of information is not
+# available to be displayed. For example a certificate that has no organization
+# defined:
+#   Organization: <Not Available>
+netmonitor.security.notAvailable=<Dim ar gael>
+
+# LOCALIZATION NOTE (collapseDetailsPane): This is the tooltip for the button
+# that collapses the network details pane in the UI.
+collapseDetailsPane=Cuddio manylion ceisiadau
+
+# LOCALIZATION NOTE (collapseActionPane): This is the tooltip for the button
+# that collapses the network action pane in the UI.
+collapseActionPane=Cuddio gweithredu rhwydwaith
+
+# LOCALIZATION NOTE (allTabsMenuButton.tooltip): The tooltip that gets
+# displayed when hovering over the tabs overflow button.
+allTabsMenuButton.tooltip=Dangos pob tab
+
+# LOCALIZATION NOTE (headersEmptyText): This is the text displayed in the
+# headers tab of the network details pane when there are no headers available.
+headersEmptyText=Dim pennyn ar gyfer y cais hwn
+
+# LOCALIZATION NOTE (headersFilterText): This is the text displayed in the
+# headers tab of the network details pane for the filtering input.
+headersFilterText=Penynnau hidlo
+
+# LOCALIZATION NOTE (messagesEmptyText): This is the text displayed in the
+# WebSockets tab of the network details pane when there are no frames available.
+messagesEmptyText=Dim negeseuon ar gyfer y cais hwn
+
+# LOCALIZATION NOTE (cookiesEmptyText): This is the text displayed in the
+# cookies tab of the network details pane when there are no cookies available.
+cookiesEmptyText=Dim cwcis ar gyfer y cais hwn
+
+# LOCALIZATION NOTE (cookiesFilterText): This is the text displayed in the
+# cookies tab of the network details pane for the filtering input.
+cookiesFilterText=Hidlo cwcis
+
+# LOCALIZATION NOTE (responseEmptyText): This is the text displayed in the
+# response tab of the network details pane when the response is empty or not
+# available for shown.
+responseEmptyText=Does dim data ymateb ar gael ar gyfer y cais hwn
+
+# LOCALIZATION NOTE (paramsEmptyText): This is the text displayed in the
+# request tab of the network details pane when there are no params available.
+paramsEmptyText=Dim paramedrau ar gyfer y cais
+
+# LOCALIZATION NOTE (paramsFilterText): This is the text displayed in the
+# request tab of the network details pane for the filtering input.
+paramsFilterText=Hidlo cais paramedrau
+
+# LOCALIZATION NOTE (paramsQueryString): This is the label displayed
+# in the network details request tab identifying the query string.
+paramsQueryString=Llinyn ymholi
+
+# LOCALIZATION NOTE (paramsFormData): This is the label displayed
+# in the network details request tab identifying the form data.
+paramsFormData=Data ffurflen
+
+# LOCALIZATION NOTE (paramsPostPayload): This is the label displayed
+# in the network details request tab identifying the request payload.
+paramsPostPayload=Llwyth gofyn
+
+# LOCALIZATION NOTE (requestHeaders): This is the label displayed
+# in the network details headers tab identifying the request headers.
+requestHeaders=Penynnau gofyn
+
+# LOCALIZATION NOTE (requestHeadersFromUpload): This is the label displayed
+# in the network details headers tab identifying the request headers from
+# the upload stream of a POST request's body.
+requestHeadersFromUpload=Pennyn cais o'r drefn uwch
+
+# LOCALIZATION NOTE (responseHeaders): This is the label displayed
+# in the network details headers tab identifying the response headers.
+responseHeaders=Penynnau ymateb
+
+# LOCALIZATION NOTE (requestCookies): This is the label displayed
+# in the network details request tab identifying the request cookies.
+requestCookies=Cwcis gofyn
+
+# LOCALIZATION NOTE (responseCookies): This is the label displayed
+# in the network details request tab identifying the response cookies.
+responseCookies=Cwcis gofyn
+
+# LOCALIZATION NOTE (responsePayload): This is the label displayed
+# in the network details response tab identifying the response payload.
+responsePayload=Llwyth ymateb
+
+# LOCALIZATION NOTE (jsonFilterText): This is the text displayed
+# in the response tab of the network details pane for the JSON filtering input.
+jsonFilterText=Priodweddau hidlo
+
+# LOCALIZATION NOTE (jsonScopeName): This is the text displayed
+# in the response tab of the network details pane for a JSON scope.
+jsonScopeName=JSON
+
+# LOCALIZATION NOTE (jsonpScopeName): This is the text displayed
+# in the response tab of the network details pane for a JSONP scope.
+jsonpScopeName=JSONP → adalw %S()
+
+# LOCALIZATION NOTE (responseTruncated): This is the text displayed
+# in the response tab of the network details pane when the response is over
+# the truncation limit and thus was truncated.
+responseTruncated=Ymateb wedi ei dalfyrru
+
+# LOCALIZATION NOTE (requestTruncated): This is the text displayed
+# in the request tab of the network details pane when the request is over
+# the truncation limit and thus was truncated.
+requestTruncated=Cais wedi ei dalfyrru
+
+# LOCALIZATION NOTE (responsePreview): This is the text displayed
+# in the response tab of the network details pane for an HTML preview.
+responsePreview=Rhagolwg
+
+# LOCALIZATION NOTE (networkMenu.raced): This is the label displayed
+# in the network menu specifying the transfer or a request is
+# raced. %S refers to the current transfer size.
+networkMenu.raced=%S (rasio)
+
+# LOCALIZATION NOTE (networkMenu.sortedAsc): This is the tooltip displayed
+# in the network table toolbar, for any column that is sorted ascending.
+networkMenu.sortedAsc=Trefnu esgynnol
+
+# LOCALIZATION NOTE (networkMenu.sortedDesc): This is the tooltip displayed
+# in the network table toolbar, for any column that is sorted descending.
+networkMenu.sortedDesc=Trefnu disgynnol
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.perf): A tooltip explaining
+# what the perf button does
+networkMenu.summary.tooltip.perf=Cychwyn dadansoddi perfformiad
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.domContentLoaded): A tooltip explaining
+# what the DOMContentLoaded label displays
+networkMenu.summary.tooltip.domContentLoaded=Yr amser pryd ddigwyddodd digwyddiad “DOMContentLoad”
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.load): A tooltip explaining
+# what the load label displays
+networkMenu.summary.tooltip.load=Yr amser pryd ddigwyddodd y digwyddiad “load”
+
+# LOCALIZATION NOTE (networkMenu.summary.requestsCount2): This label is displayed
+# in the network table footer providing the number of requests
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+networkMenu.summary.requestsCount2=Dim ceisiadau;#1 cais;#1 gais;#1 cais;#1 chais;#1 cais
+
+# LOCALIZATION NOTE (networkMenu.summary.requestsCountEmpty): This label is displayed
+# in the network table footer when there are no requests
+networkMenu.summary.requestsCountEmpty=Dim ceisiadau
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.requestsCount): A tooltip explaining
+# what the requestsCount label displays
+networkMenu.summary.tooltip.requestsCount=Nifer y ceisiadau
+
+# LOCALIZATION NOTE (networkMenu.summary.transferred): This label is displayed
+# in the network table footer providing the transferred size.
+networkMenu.summary.transferred=%S / %S wedi eu trosglwyddo
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.transferred): A tooltip explaining
+# what the transferred label displays
+networkMenu.summary.tooltip.transferred=Maint/maint trosglwyddo pob cais
+
+# LOCALIZATION NOTE (networkMenu.summary.finish): This label is displayed
+# in the network table footer providing the transfer time.
+networkMenu.summary.finish=Gorffen: %S
+
+# LOCALIZATION NOTE (networkMenu.summary.tooltip.finish): A tooltip explaining
+# what the finish label displays
+networkMenu.summary.tooltip.finish=Cyfanswm yr amser oedd ei angen i lwytho pob cais
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.framesCount2): This label is displayed
+# in the messages table footer providing the number of frames
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+networkMenu.ws.summary.framesCount2=Un neges:#1 neges;#1 neges;#1 neges;#1 neges;#1 neges;#1 neges
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.framesCountEmpty): This label is displayed
+# in the messages table footer when there are no frames
+networkMenu.ws.summary.framesCountEmpty=Dim negeseuon
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.tooltip.framesCount): A tooltip explaining
+# what the framesCount label displays
+networkMenu.ws.summary.tooltip.framesCount=Y nifer o negeseuon
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.tooltip.framesTotalSize): A tooltip explaining
+# what the framesTotalSize label displays
+networkMenu.ws.summary.tooltip.framesTotalSize=Cyfanswm maint y negeseuon sy'n cael eu harddangos
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.label.framesTranferredSize): A label showing
+# summary size info related to the current list of WS messages
+# %1$S is the total size of the transferred data, %2$S is the size of sent data, %3$S is the size of received data.
+networkMenu.ws.summary.label.framesTranferredSize=Cyfanswm %1$S, %2$SS wedi'i anfon, %3$S wedi'u derbyn
+
+# LOCALIZATION NOTE (networkMenu.ws.summary.tooltip.framesTotalTime): A tooltip explaining
+# what framesTotalTime displays
+networkMenu.ws.summary.tooltip.framesTotalTime=Cyfanswm yr amser a aeth heibio rhwng y negeseuon cyntaf ac olaf a ddangoswyd
+
+# LOCALIZATION NOTE (networkMenu.sizeB): This is the label displayed
+# in the network menu specifying the size of a request (in bytes).
+networkMenu.sizeB=%S B
+
+# LOCALIZATION NOTE (networkMenu.sizeKB): This is the label displayed
+# in the network menu specifying the size of a request (in kilobytes).
+networkMenu.sizeKB=%S KB
+
+# LOCALIZATION NOTE (networkMenu.sizeMB): This is the label displayed
+# in the network menu specifying the size of a request (in megabytes).
+networkMenu.sizeMB=%S MB
+
+# LOCALIZATION NOTE (networkMenu.sizeGB): This is the label displayed
+# in the network menu specifying the size of a request (in gigabytes).
+networkMenu.sizeGB=%S GB
+
+# LOCALIZATION NOTE (networkMenu.sizeUnavailable): This is the label displayed
+# in the network menu specifying the transferred size of a request is
+# unavailable.
+networkMenu.sizeUnavailable=—
+
+# LOCALIZATION NOTE (networkMenu.sizeUnavailable.title): This is the tooltip
+# displayed in the network menu specifying that the transferred size of a
+# request is unavailable.
+networkMenu.sizeUnavailable.title=Nid yw'r maint trosglwyddwyd ar gael
+
+# LOCALIZATION NOTE (networkMenu.sizeCached): This is the label displayed
+# in the network menu and the headers panel specifying the transfer or a request is
+# cached.
+networkMenu.sizeCached=storiwyd dros dro
+
+# LOCALIZATION NOTE (networkMenu.sizeServiceWorker): This is the label displayed
+# in the network menu and the headers panel specifying the transferred of a request
+# computed by a service worker.
+networkMenu.sizeServiceWorker=service worker
+
+# LOCALIZATION NOTE (networkMenu.blocked2): This is a generic message for a
+# URL that has been blocked for an unknown reason
+networkMenu.blocked2=Rhwystrwyd
+
+# LOCALIZATION NOTE (networkMenu.blockedby): This is a generic message for a
+# URL that has been blocked by an extension
+# %S is the extension name.
+networkMenu.blockedby=Rhwystrwyd gan %S
+
+# LOCALIZATION NOTE (networkMenu.blockedTooltip): This is a the text displayed
+# as a tooltip for the blocked icon in the request list
+networkMenu.blockedTooltip=Rhwystrwyd
+
+# LOCALIZATION NOTE (networkMenu.totalMS2): This is the label displayed
+# in the network menu specifying the time for a request to finish (in milliseconds).
+networkMenu.totalMS2=%S ms
+
+# This string is used to concatenate tooltips (netmonitor.waterfall.tooltip.*)
+# in the requests waterfall for total time (in milliseconds). \\u0020 represents
+# a whitespace. You can replace this with a different character, e.g. an hyphen
+# or a period, if a comma doesn't work for your language.
+netmonitor.waterfall.tooltip.separator=,\u0020
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.total): This is part of the tooltip
+# displayed in the requests waterfall for total time (in milliseconds).
+netmonitor.waterfall.tooltip.total=Cyfanswm %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.blocked): This is part of the tooltip
+# displayed in the requests waterfall for blocked time (in milliseconds).
+netmonitor.waterfall.tooltip.blocked=Rhwystrwyd %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.dns): This is part of the tooltip
+# displayed in the requests waterfall for dns time (in milliseconds).
+netmonitor.waterfall.tooltip.dns=DNS %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.ssl): This is part of the tooltip
+# displayed in the requests waterfall for tls setup time (in milliseconds).
+netmonitor.waterfall.tooltip.ssl=TLS %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.connect): This is part of the tooltip
+# displayed in the requests waterfall for connect time (in milliseconds).
+netmonitor.waterfall.tooltip.connect=Cysylltu %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.send): This is part of the tooltip
+# displayed in the requests waterfall for send time (in milliseconds).
+netmonitor.waterfall.tooltip.send=Anfon %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.wait): This is part of the tooltip
+# displayed in the requests waterfall for wait time (in milliseconds).
+netmonitor.waterfall.tooltip.wait=Aros %S ms
+
+# LOCALIZATION NOTE (netmonitor.waterfall.tooltip.receive): This is part of the tooltip
+# displayed in the requests waterfall for receive time (in milliseiconds).
+netmonitor.waterfall.tooltip.receive=Derbyn %S ms
+
+# LOCALIZATION NOTE (netmonitor.timings.requestTiming): This is the title of the existing
+# section in Timings side panel. This section contains request timings.
+netmonitor.timings.requestTiming=Gofyn am Amseru
+
+# LOCALIZATION NOTE (netmonitor.timings.serverTiming): This is the title of a new section
+# in Timings side panel. This section contains server timings transferred from the server
+# through the "Server-Timing" header.
+netmonitor.timings.serverTiming=Amseru Gweinydd
+
+# LOCALIZATION NOTE (netmonitor.timings.queuedAt): This is relative queued time to the
+# first request. %S is time expressed in milliseconds or minutes.
+netmonitor.timings.queuedAt=Ciwio: %S
+
+# LOCALIZATION NOTE (netmonitor.timings.startedAt): Relative to the first request,
+# when the request actually started. %S is time expressed in milliseconds or minutes.
+netmonitor.timings.startedAt=Cychwynwyd: %S
+
+# LOCALIZATION NOTE (netmonitor.timings.downloadedAt): Relative to first request,
+# when the request actually finished downloading.
+# %S is time expressed in milliseconds or minutes.
+netmonitor.timings.downloadedAt=Llwythwyd i Lawr: %S
+
+# LOCALIZATION NOTE (netmonitor.timings.noTimings): Message that displays in the
+# timings pane when thea request has been blocked
+netmonitor.timings.noTimings=Dim amseriadau ar gyfer y cais hwn
+
+# LOCALIZATION NOTE (networkMenu.millisecond): This is the label displayed
+# in the network menu specifying timing interval divisions (in milliseconds).
+networkMenu.millisecond=%S ms
+
+# LOCALIZATION NOTE (networkMenu.second): This is the label displayed
+# in the network menu specifying timing interval divisions (in seconds).
+networkMenu.second=%S s
+
+# LOCALIZATION NOTE (networkMenu.minute): This is the label displayed
+# in the network menu specifying timing interval divisions (in minutes).
+networkMenu.minute=%S mun
+
+# LOCALIZATION NOTE (pieChart.loading): This is the label displayed
+# for pie charts (e.g., in the performance analysis view) when there is
+# no data available yet.
+pieChart.loading=Llwytho
+
+# LOCALIZATION NOTE (pieChart.unavailable): This is the label displayed
+# for pie charts (e.g., in the performance analysis view) when there is
+# no data available, even after loading it.
+pieChart.unavailable=Gwag
+
+# LOCALIZATION NOTE (tableChart.loading): This is the label displayed
+# for table charts (e.g., in the performance analysis view) when there is
+# no data available yet.
+tableChart.loading=Arhoswch…
+
+# LOCALIZATION NOTE (tableChart.unavailable): This is the label displayed
+# for table charts (e.g., in the performance analysis view) when there is
+# no data available, even after loading it.
+tableChart.unavailable=Dim data ar gael
+
+# LOCALIZATION NOTE (charts.sizeKB): This is the label displayed
+# in pie or table charts specifying the size of a request (in kilobytes).
+charts.sizeKB=%S KB
+
+# LOCALIZATION NOTE (charts.transferredSizeKB): This is the label displayed
+# in pie or table charts specifying the size of a transferred request (in kilobytes).
+charts.transferredSizeKB=%S KB
+
+# LOCALIZATION NOTE (charts.totalS): This is the label displayed
+# in pie or table charts specifying the time for a request to finish (in seconds).
+charts.totalS=%S s
+
+# LOCALIZATION NOTE (charts.totalTransferredSize): This is the label displayed
+# in the performance analysis view for total transferred size, in kilobytes.
+charts.totalTransferredSize=Maint Trosglwyddo: %S KB
+
+# LOCALIZATION NOTE (charts.cacheEnabled): This is the label displayed
+# in the performance analysis view for "cache enabled" charts.
+charts.cacheEnabled=Storfa dros dro wedi ymgychwyn
+
+# LOCALIZATION NOTE (charts.cacheDisabled): This is the label displayed
+# in the performance analysis view for "cache disabled" charts.
+charts.cacheDisabled=Gwagio'r storfa dros dro
+
+# LOCALIZATION NOTE (charts.learnMore): This is the label displayed
+# in the performance analysis view, with a link to external documentation.
+charts.learnMore=Dysgu rhagor am yr ddadansoddi perfformiad
+
+# LOCALIZATION NOTE (charts.totalSize): This is the label displayed
+# in the performance analysis view for total requests size, in kilobytes.
+charts.totalSize=Maint: %S KB
+
+# LOCALIZATION NOTE (charts.totalSeconds): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This is the label displayed in the performance analysis view for the
+# total requests time, in seconds.
+charts.totalSeconds=Dim Amserau;Amser: #1 eiliad;Amser: #1 eiliad;Amser: #1 eiliad;Amser: #1 eiliad;Amser: #1 eiliad
+
+# LOCALIZATION NOTE (charts.totalSecondsNonBlocking): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This is the label displayed in the performance analysis view for the
+# total requests time (non-blocking), in seconds.
+charts.totalSecondsNonBlocking=Dim amserau heb eu rhwystro;Amser heb ei rwystro: #1 eiliad;Amser heb ei rwystro: #1 eiliad;Amser heb ei rwystro: #1 eiliad;Amser heb ei rwystro: #1 eiliad;Amser heb ei rwystro: #1 eiliad
+
+# LOCALIZATION NOTE (charts.totalCached): This is the label displayed
+# in the performance analysis view for total cached responses.
+charts.totalCached=Ymatebion storfa dros dro: %S
+
+# LOCALIZATION NOTE (charts.totalCount): This is the label displayed
+# in the performance analysis view for total requests.
+charts.totalCount=Cyfanswm ceisiadau: %S
+
+# LOCALIZATION NOTE (charts.size): This is the label displayed
+# in the header column in the performance analysis view for size of the request.
+charts.size=Maint
+
+# LOCALIZATION NOTE (charts.type): This is the label displayed
+# in the header column in the performance analysis view for type of request.
+charts.type=Math
+
+# LOCALIZATION NOTE (charts.transferred): This is the label displayed
+# in the header column in the performance analysis view for transferred
+# size of the request.
+charts.transferred=Trosglwyddwyd
+
+# LOCALIZATION NOTE (charts.time): This is the label displayed
+# in the header column in the performance analysis view for time of request.
+charts.time=Amser
+
+# LOCALIZATION NOTE (charts.nonBlockingTime): This is the label displayed
+# in the header column in the performance analysis view for non blocking
+# time of request.
+charts.nonBlockingTime=Amser heb ei rwystro
+
+# LOCALIZATION NOTE (netRequest.originalFileURL.tooltip): This is the tooltip
+# displayed for the file's original URL value displayed in the file column of
+# a request.
+netRequest.originalFileURL.tooltip=Gwreiddiol: %S
+
+# LOCALIZATION NOTE (netRequest.decodedFileURL.tooltip): This is the tooltip
+# displayed for the file's decoded URL value displayed in the file column of
+# a request.
+netRequest.decodedFileURL.tooltip=Wedi'i ddadgodio: %S
+
+# LOCALIZATION NOTE (certmgr.subjectinfo.label):
+# A label used for a certificate section in security tab.
+# This section displays Name and organization who has been assigned the fingerprints
+certmgr.subjectinfo.label=Dynodwyd i
+
+# LOCALIZATION NOTE (certmgr.certdetail.cn):
+# A label used for Issued To and Issued By sub-section in security tab
+certmgr.certdetail.cn=Enw Cyffredin (CN):
+
+# LOCALIZATION NOTE (certmgr.certdetail.o):
+# A label used for Issued To and Issued By sub-section in security tab
+certmgr.certdetail.o=Corff (O):
+
+# LOCALIZATION NOTE (certmgr.certdetail.ou):
+# A label used for Issued To and Issued By sub-section in security tab
+certmgr.certdetail.ou=Uned Corff (OU):
+
+# LOCALIZATION NOTE (certmgr.issuerinfo.label):
+# A label used for a certificate section in security tab
+# This section displays Name and organization who issued the fingerprints
+certmgr.issuerinfo.label=Cyhoeddwyd Gan
+
+# LOCALIZATION NOTE (certmgr.periodofvalidity.label):
+# A label used for a certificate section in security tab
+# This section displays the valid period of this fingerprints
+certmgr.periodofvalidity.label=Cyfnod Dilysrwydd
+
+# LOCALIZATION NOTE (certmgr.begins):
+# A label used for Period of Validity sub-section in security tab
+certmgr.begins=Cychwyn ar:
+
+# LOCALIZATION NOTE (certmgr.expires):
+# A label used for Period of Validity sub-section in security tab
+certmgr.expires=Gorffen ar:
+
+# LOCALIZATION NOTE (certmgr.fingerprints.label):
+# A label used for a certificate section in security tab
+# This section displays the valid period of this fingerprints
+certmgr.fingerprints.label=Olion Bysedd
+
+# LOCALIZATION NOTE (certmgr.certdetail.sha256fingerprint):
+# A label used for Fingerprints sub-section in security tab
+certmgr.certdetail.sha256fingerprint=Ôl bys SHA-256:
+
+# LOCALIZATION NOTE (certmgr.certdetail.sha1fingerprint):
+# A label used for Fingerprints sub-section in security tab
+certmgr.certdetail.sha1fingerprint=Ôl Bys SHA1:
+
+# LOCALIZATION NOTE (certmgr.certificateTransparency.label):
+# This string is used as a label in the security tab.
+certmgr.certificateTransparency.label=Tryloywder:
+
+# LOCALIZATION NOTE (certmgr.certificateTransparency.status.ok):
+# This string is used to indicate that there are valid signed certificate
+# timestamps. This is a property for the 'Transparency'
+# field in the security tab.
+certmgr.certificateTransparency.status.ok=Cofnodion SCT dilys
+
+# LOCALIZATION NOTE (certmgr.certificateTransparency.status.notEnoughSCTS):
+# This string is used to indicate that there are not enough valid signed
+# certificate timestamps. This is a property for the 'Transparency'
+# field in the security tab.
+certmgr.certificateTransparency.status.notEnoughSCTS=Dim digon o SCT
+
+# LOCALIZATION NOTE (certmgr.certificateTransparency.status.notDiverseSCTS):
+# This string is used to indicate that there ar not enough diverse signed
+# certificate timestamps. This is a property for the 'Transparency'
+# field in the security tab.
+certmgr.certificateTransparency.status.notDiverseSCTS=Dim SCT amrywiol
+
+# LOCALIZATION NOTE (netmonitor.perfNotice1/2/3): These are the labels displayed
+# in the network table when empty to start performance analysis.
+netmonitor.perfNotice1=• Clicio ar y botwm
+netmonitor.perfNotice2=i gychwyn dadansoddi perfformiad.
+netmonitor.perfNotice3=Dadansoddi
+
+# LOCALIZATION NOTE (netmonitor.reload1/2/3): These are the labels displayed
+# in the network table when empty to start logging network requests.
+netmonitor.reloadNotice1=• Gwneud cais neu
+netmonitor.reloadNotice2=Ail-lwytho
+netmonitor.reloadNotice3=y dudalen i weld gwybodaeth fanwl am weithgaredd y rhwydwaith.
+
+# LOCALIZATION NOTE (netmonitor.toolbar.status3): This is the label displayed
+# in the network table toolbar, above the "status" column.
+netmonitor.toolbar.status3=Statws
+
+# LOCALIZATION NOTE (netmonitor.toolbar.method): This is the label displayed
+# in the network table toolbar, above the "method" column.
+netmonitor.toolbar.method=Dull
+
+# LOCALIZATION NOTE (netmonitor.toolbar.file): This is the label displayed
+# in the network table toolbar, above the "file" column.
+netmonitor.toolbar.file=Ffeil
+
+# LOCALIZATION NOTE (netmonitor.toolbar.url): This is the label displayed
+# in the network table toolbar, above the "url" column.
+netmonitor.toolbar.url=URL
+
+# LOCALIZATION NOTE (netmonitor.toolbar.protocol): This is the label displayed
+# in the network table toolbar, above the "protocol" column.
+netmonitor.toolbar.protocol=Protocol
+
+# LOCALIZATION NOTE (netmonitor.toolbar.domain): This is the label displayed
+# in the network table toolbar, above the "domain" column.
+netmonitor.toolbar.domain=Parth
+
+# LOCALIZATION NOTE (netmonitor.toolbar.remoteip): This is the label displayed
+# in the network table toolbar, above the "remoteip" column.
+netmonitor.toolbar.remoteip=IP pell
+
+# LOCALIZATION NOTE (netmonitor.toolbar.initiator): This is the label displayed
+# in the network table toolbar, above the "initiator" column.
+netmonitor.toolbar.initiator=Cychwynnwr
+
+# LOCALIZATION NOTE (netmonitor.toolbar.type): This is the label displayed
+# in the network table toolbar, above the "type" column.
+netmonitor.toolbar.type=Math
+
+# LOCALIZATION NOTE (netmonitor.toolbar.cookies): This is the label displayed
+# in the network table toolbar, above the "cookies" column.
+netmonitor.toolbar.cookies=Cwcis
+
+# LOCALIZATION NOTE (netmonitor.toolbar.setCookies): This is the label displayed
+# in the network table toolbar, above the "set cookies" column.
+# Set-Cookie is a HTTP response header. This string is the plural form of it.
+# See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie
+netmonitor.toolbar.setCookies=Gosod Cwcis
+
+# LOCALIZATION NOTE (netmonitor.toolbar.scheme): This is the label displayed
+# in the network table toolbar, above the "scheme" column.
+netmonitor.toolbar.scheme=Cynllun
+
+# LOCALIZATION NOTE (netmonitor.toolbar.startTime): This is the label displayed
+# in the network table toolbar, above the "start time" column, which is the time
+# from start of 1st request until the start of this request.
+netmonitor.toolbar.startTime=Amser Cychwyn
+
+# LOCALIZATION NOTE (netmonitor.toolbar.endTime): This is the label displayed
+# in the network table toolbar, above the "end time" column, which is the time
+# from start of 1st request until the end of this response.
+netmonitor.toolbar.endTime=Amser Gorffen
+
+# LOCALIZATION NOTE (netmonitor.toolbar.responseTime): This is the label displayed
+# in the network table toolbar, above the "response time" column, which is the time
+# from start of 1st request until the beginning of download of this response.
+netmonitor.toolbar.responseTime=Amser Ymateb
+
+# LOCALIZATION NOTE (netmonitor.toolbar.duration): This is the label displayed
+# in the network table toolbar, above the "duration" column, which is the time
+# from start of this request until the end of this response.
+netmonitor.toolbar.duration=Hyd
+
+# LOCALIZATION NOTE (netmonitor.toolbar.latency): This is the label displayed
+# in the network table toolbar, above the "latency" column, which is the time
+# from end of this request until the beginning of download of this response.
+netmonitor.toolbar.latency=Cuddni
+
+# LOCALIZATION NOTE (netmonitor.toolbar.transferred): This is the label displayed
+# in the network table toolbar, above the "transferred" column and in general
+# section of the headers panel, which is the compressed / encoded size.
+netmonitor.toolbar.transferred=Trosglwyddwyd
+
+# LOCALIZATION NOTE (netmonitor.toolbar.contentSize): This is the label displayed
+# in the network table toolbar, above the "size" column, which is the
+# uncompressed / decoded size.
+netmonitor.toolbar.contentSize=Maint
+
+# LOCALIZATION NOTE (netmonitor.toolbar.waterfall): This is the label displayed
+# in the network table toolbar, above the "waterfall" column.
+netmonitor.toolbar.waterfall=Llinell Amser
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.size): This is the label displayed
+# in the messages table header, above the "size" column.
+netmonitor.ws.toolbar.size=Maint
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.data): This is the label displayed
+# in the messages table header, above the "data" column.
+netmonitor.ws.toolbar.data=Data
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.opCode): This is the label displayed
+# in the messages table header, above the "opCode" column.
+netmonitor.ws.toolbar.opCode=OpCode
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.maskBit): This is the label displayed
+# in the messages table header, above the "maskBit" column.
+netmonitor.ws.toolbar.maskBit=MaskBit
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.finBit): This is the label displayed
+# in the messages table header, above the "finBit" column.
+netmonitor.ws.toolbar.finBit=FinBit
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.time): This is the label displayed
+# in the messages table header, above the "time" column.
+netmonitor.ws.toolbar.time=Amser
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.eventName): This is the label displayed
+# in the messages table header, above the "eventName" column.
+netmonitor.ws.toolbar.eventName=Enw Digwyddiad
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.retry): This is the label displayed
+# in the messages table header, above the "retry" column.
+netmonitor.ws.toolbar.retry=Ceisio eto
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.lastEventId): This is the label displayed
+# in the messages table header, above the "lastEventId" column.
+netmonitor.ws.toolbar.lastEventId=ID Digwyddiad Diwethaf
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.clear): This is the label displayed
+# in the messages panel toolbar for the "Clear" button.
+netmonitor.ws.toolbar.clear=Clir
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.filterFreetext.label): This is the label
+# displayed in the messages panel toolbar for the frames filtering textbox.
+netmonitor.ws.toolbar.filterFreetext.label=Hidlo Negeseuon
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.filterFreetext.key): This is the
+# shortcut key to focus on the messages panel toolbar messages filtering textbox
+netmonitor.ws.toolbar.filterFreetext.key=CmdOrCtrl+E
+
+# LOCALIZATION NOTE (netmonitor.ws.toolbar.resetColumns): This is the label
+# displayed in the messages panel table header context menu.
+netmonitor.ws.toolbar.resetColumns=Ailosod Colofnau
+
+# LOCALIZATION NOTE (netmonitor.ws.context.all): This is the label displayed
+# on the context menu that shows "All" WebSocket frames.
+netmonitor.ws.context.all=Y Cyfan
+
+# LOCALIZATION NOTE (netmonitor.ws.context.all.accesskey): This is the access key
+# for the "All" menu item displayed in the context menu in the websocket toolbar.
+netmonitor.ws.context.all.accesskey=C
+
+# LOCALIZATION NOTE (netmonitor.ws.context.sent): This is the label displayed
+# on the context menu that shows "Sent" WebSocket frames.
+netmonitor.ws.context.sent=Anfonwyd
+
+# LOCALIZATION NOTE (netmonitor.ws.context.sent.accesskey): This is the access key
+# for the "Sent" menu item displayed in the context menu in the websocket toolbar.
+netmonitor.ws.context.sent.accesskey=A
+
+# LOCALIZATION NOTE (netmonitor.ws.context.received): This is the label displayed
+# on the context menu that shows "Received" WebSocket frames.
+netmonitor.ws.context.received=Derbyniwyd
+
+# LOCALIZATION NOTE (netmonitor.ws.context.received.accesskey): This is the access key
+# for the "Received" menu item displayed in the context menu in the websocket toolbar.
+netmonitor.ws.context.received.accesskey=D
+
+# LOCALIZATION NOTE (netmonitor.ws.context.controlFrames): This is the label displayed
+# on the context menu that shows "Control Frames" WebSocket frames.
+netmonitor.ws.context.controlFrames=Rheoli
+
+# LOCALIZATION NOTE (netmonitor.ws.context.controlFrames.accesskey): This is the access key
+# for the "Control Frames" menu item displayed in the context menu in the websocket toolbar.
+netmonitor.ws.context.controlFrames.accesskey=R
+
+# LOCALIZATION NOTE (netmonitor.ws.context.copyFrame): This is the label displayed
+# on the context menu that shows "Copy Message".
+netmonitor.ws.context.copyFrame=Copïo Neges
+
+# LOCALIZATION NOTE (netmonitor.ws.context.copyFrame.accesskey): This is the access key
+# for the "Copy Message" menu item displayed in the context menu of a WebSocket frame.
+netmonitor.ws.context.copyFrame.accesskey=C
+
+# LOCALIZATION NOTE (netmonitor.ws.connection.closed): This is the text displayed in the
+# websocket messages panel when the connection is closed
+netmonitor.ws.connection.closed=Cysylltiad wedi Cau
+
+# LOCALIZATION NOTE (netmonitor.ws.type.sent): This is the label used as
+# accessible text for the "sent" type icon in the websocket table's "data" column.
+netmonitor.ws.type.sent=Anfonwyd
+
+# LOCALIZATION NOTE (netmonitor.ws.type.received): This is the label used as
+# accessible text for the "received" type icon in the websocket table's "data" column.
+netmonitor.ws.type.received=Derbyniwyd
+
+# LOCALIZATION NOTE (netmonitor.ws.rawData.header): This is the label displayed
+# in the messages panel identifying the raw data.
+netmonitor.ws.rawData.header=Data Crai (%S)
+
+# LOCALIZATION NOTE (netmonitor.search.toolbar.inputPlaceholder): This is the label
+# displayed in the search toolbar for the search input as the placeholder.
+netmonitor.search.toolbar.inputPlaceholder=Canfod yn yr adnoddau...
+
+# LOCALIZATION NOTE (netmonitor.search.toolbar.close): This is the label
+# displayed in the search toolbar to close the search panel.
+netmonitor.search.toolbar.close=Cau'r Panel Chwilio
+
+# LOCALIZATION NOTE (netmonitor.search.toolbar.clear): This is the label
+# displayed in the search toolbar to clear the search panel.
+netmonitor.search.toolbar.clear=Clirio'r Canlyniadau Chwilio
+
+# LOCALIZATION NOTE (netmonitor.search.toolbar.caseSensitive): This is the label
+# displayed in the search toolbar to do a case sensitive search.
+netmonitor.search.toolbar.caseSensitive=Sensitif i Faint Nodau
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.fetching): This is the label
+# displayed in the search results status bar when status is set to fetching.
+netmonitor.search.status.labels.fetching=Chwilio…
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.canceled): This is the label
+# displayed in the search results status bar when status is set to cancelled.
+netmonitor.search.status.labels.canceled=Chwilio wedi'i ddileu.
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.done): This is the label
+# displayed in the search results status bar when status is set to done.
+# %1$S is the number of matching lines in search results (netmonitor.search.status.labels.matchingLines)
+# %2$S is the number of files in which matching lines were found (netmonitor.search.status.labels.fileCount)
+netmonitor.search.status.labels.done=Chwilio wedi gorffen. %1$S %2$S.
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.matchingLines): Semi-colon list of plural forms.
+# This is the label displayed in the search results status bar showing matching lines found.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of matching lines found
+netmonitor.search.status.labels.matchingLines=Wedi canfod #1 llinell cyfatebol;Wedi canfod #1 llinell cyfatebol;Wedi canfod #1 llinell cyfatebol;Wedi canfod #1 llinell cyfatebol;Wedi canfod #1 llinell cyfatebol;Wedi canfod #1 llinell cyfatebol
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.fileCount): Semi-colon list of plural forms.
+# This is the label displayed in the search results status bar showing file count
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of files in which matching lines were found
+netmonitor.search.status.labels.fileCount=mewn #1 ffeil ;mewn #1 ffeil;mewn #1 ffeil;mewn #1 ffeil;mewn #1 ffeil;mewn #1 ffeil
+
+# LOCALIZATION NOTE (netmonitor.search.status.labels.error): This is the label
+# displayed in the search results status bar when status is set to error.
+netmonitor.search.status.labels.error=Gwall chwilio.
+
+# LOCALIZATION NOTE (netmonitor.toolbar.requestBlocking): This is the tooltip displayed
+# over the toolbar's Request Blocking buttonn
+netmonitor.toolbar.requestBlocking=Gofyn am Rwystro
+
+# LOCALIZATION NOTE (netmonitor.actionbar.requestBlocking2): This is the label displayed
+# in the action bar's request blocking tab
+netmonitor.actionbar.requestBlocking2=Rhwystro
+
+# LOCALIZATION NOTE (netmonitor.actionbar.enableBlocking): This is the label displayed
+# in request blocking tab to represent if requests blocking should be enabled
+netmonitor.actionbar.enableBlocking=Galluogi Cais Rhwystro
+
+# LOCALIZATION NOTE (netmonitor.actionbar.blockSearchPlaceholder): This is the
+# placeholder text for the request addition form
+netmonitor.actionbar.blockSearchPlaceholder=Rhwystro adnodd pan fydd URL yn cynnwys
+
+# LOCALIZATION NOTE (netmonitor.actionbar.removeBlockedUrl): This is the
+# tooltip shown over the remove button for blocked URL item
+netmonitor.actionbar.removeBlockedUrl=Tynnu patrwm
+
+# LOCALIZATION NOTE (netmonitor.actionbar.requestBlockingUsageNotice): This is the
+# usage notice displayed when network blocking list is empty
+netmonitor.actionbar.requestBlockingUsageNotice=Ychwanegwch batrymau URL yma i rwystro ceisiadau cydweddu.
+
+# LOCALIZATION NOTE (netmonitor.actionbar.requestBlockingAddNotice): This is the
+# add notice that explains ways to add blocking pattern that is displayed when
+# network blocking list is empty
+netmonitor.actionbar.requestBlockingAddNotice=Cychwynnwch drwy ychwanegu patrwm neu lusgo rhes o'r tabl rhwydwaith.
+
+# LOCALIZATION NOTE (netmonitor.requestBlockingMenu.removeAllBlockedUrls): This is the
+# context menu item for removing all blocked URLs
+netmonitor.requestBlockingMenu.removeAllBlockedUrls=Tynnu popeth
+
+# LOCALIZATION NOTE (netmonitor.requestBlockingMenu.enableAllBlockedUrls): This is the
+# context menu item for enabling all blocked URLs
+netmonitor.requestBlockingMenu.enableAllBlockedUrls=Galluogi popeth
+
+# LOCALIZATION NOTE (netmonitor.requestBlockingMenu.disableAllBlockedUrls): This is the
+# context menu item for disabling all blocked URLs
+netmonitor.requestBlockingMenu.disableAllBlockedUrls=Analluogi popeth
+
+# LOCALIZATION NOTE (netmonitor.actionbar.search): This is the label displayed
+# in the action bar's search tab
+netmonitor.actionbar.search=Chwilio
+
+# LOCALIZATION NOTE (messagesTruncated): This is the text displayed
+# in the messages panel when the number of messages is over the
+# truncation limit.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+netmonitor.ws.truncated-messages.warning=Mae un neges wedi'i chwtogi i gynilo'r cof;mae #1 neges wedi'u cwtogi i gynilo'r cof;mae #1 neges wedi'u cwtogi i gynilo'r cof;mae #1 neges wedi'u cwtogi i gynilo'r cof;mae #1 neges wedi'u cwtogi i gynilo'r cof;mae #1 neges wedi'u cwtogi i gynilo'r cof
+
+# LOCALIZATION NOTE (disableMessagesTruncation): This is the text displayed
+# in the messages panel checkbox label for toggling message truncation.
+toggleMessagesTruncation=Cadwch bob neges yn y dyfodol
+
+# LOCALIZATION NOTE (toggleMessagesTruncation.title): This is the title used
+# to describe the checkbox used to toggle message truncation.
+toggleMessagesTruncation.title=Cadw pob neges yn y dyfodol neu barhau i ddangos negeseuon wedi'u cwtogi
+
+# LOCALIZATION NOTE (messageDataTruncated): This is the text displayed
+# to describe to describe data truncation in the messages panel.
+messageDataTruncated=Mae data wedi'i gwtogi
+
+# LOCALIZATION NOTE (netmonitor.tab.headers): This is the label displayed
+# in the network details pane identifying the headers tab.
+netmonitor.tab.headers=Penynnau
+
+# LOCALIZATION NOTE (netmonitor.tab.messages): This is the label displayed
+# in the network details pane identifying the messages tab.
+netmonitor.tab.messages=Neges
+
+# LOCALIZATION NOTE (netmonitor.tab.cookies): This is the label displayed
+# in the network details pane identifying the cookies tab.
+netmonitor.tab.cookies=Cwcis
+
+# LOCALIZATION NOTE (netmonitor.tab.cache): This is the label displayed
+# in the network details pane identifying the cache tab.
+netmonitor.tab.cache=Storfa Dros Dro
+
+# LOCALIZATION NOTE (netmonitor.tab.params): This is the label displayed
+# in the network details pane identifying the params tab.
+netmonitor.tab.params=Params
+
+# LOCALIZATION NOTE (netmonitor.tab.request): This is the label displayed
+# in the network details pane identifying the request tab.
+netmonitor.tab.request=Cais
+
+# LOCALIZATION NOTE (netmonitor.tab.response): This is the label displayed
+# in the network details pane identifying the response tab.
+netmonitor.tab.response=Ymateb
+
+# LOCALIZATION NOTE (netmonitor.tab.timings): This is the label displayed
+# in the network details pane identifying the timings tab.
+netmonitor.tab.timings=Amseru
+
+# LOCALIZATION NOTE (netmonitor.tab.stackTrace): This is the label displayed
+# in the network details pane identifying the stack-trace tab.
+netmonitor.tab.stackTrace=Olrhain Stac
+
+# LOCALIZATION NOTE (netmonitor.tab.security): This is the label displayed
+# in the network details pane identifying the security tab.
+netmonitor.tab.security=Diogelwch
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.all): This is the label displayed
+# in the network toolbar for the "All" filtering button.
+netmonitor.toolbar.filter.all=Popeth
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.html): This is the label displayed
+# in the network toolbar for the "HTML" filtering button.
+netmonitor.toolbar.filter.html=HTML
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.css): This is the label displayed
+# in the network toolbar for the "CSS" filtering button.
+netmonitor.toolbar.filter.css=CSS
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.js): This is the label displayed
+# in the network toolbar for the "JS" filtering button.
+netmonitor.toolbar.filter.js=JS
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.xhr): This is the label displayed
+# in the network toolbar for the "XHR" filtering button.
+netmonitor.toolbar.filter.xhr=XHR
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.fonts): This is the label displayed
+# in the network toolbar for the "Fonts" filtering button.
+netmonitor.toolbar.filter.fonts=Ffontiau
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.images): This is the label displayed
+# in the network toolbar for the "Images" filtering button.
+netmonitor.toolbar.filter.images=Delweddau
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.media): This is the label displayed
+# in the network toolbar for the "Media" filtering button.
+netmonitor.toolbar.filter.media=Cyfrwng
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.flash): This is the label displayed
+# in the network toolbar for the "Flash" filtering button.
+netmonitor.toolbar.filter.flash=Flash
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.ws): This is the label displayed
+# in the network toolbar for the "WS" filtering button.
+netmonitor.toolbar.filter.ws=WS
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filter.other): This is the label displayed
+# in the network toolbar for the "Other" filtering button.
+netmonitor.toolbar.filter.other=Arall
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filterFreetext.label): This is the label
+# displayed in the network toolbar for the url filtering textbox.
+netmonitor.toolbar.filterFreetext.label=Hidlo URLau
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filterFreetext.key): This is the
+# shortcut key to focus on the toolbar url filtering textbox
+netmonitor.toolbar.filterFreetext.key=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (netmonitor.toolbar.search.key): This is the
+# shortcut key to toggle the search panel
+netmonitor.toolbar.search.key=CmdOrCtrl+Shift+F
+
+# LOCALIZATION NOTE (netmonitor.toolbar.copy.key): This is the
+# shortcut key to copy a selected request url from the network table
+netmonitor.toolbar.copy.key=CmdOrCtrl+C
+
+# LOCALIZATION NOTE (netmonitor.toolbar.filterFreetext.learnMore): This is
+# the title used for MDN icon in filtering textbox
+netmonitor.toolbar.filterFreetext.learnMore=Dysgu rhagor am hidlo
+
+# LOCALIZATION NOTE (netmonitor.toolbar.enablePersistentLogs.label): This is the label
+# displayed for the checkbox for enabling persistent logs.
+netmonitor.toolbar.enablePersistentLogs.label=Cofnodion Parhaol
+
+# LOCALIZATION NOTE (netmonitor.toolbar.enablePersistentLogs.tooltip): This is the tooltip
+# displayed for the checkbox for enabling persistent logs.
+netmonitor.toolbar.enablePersistentLogs.tooltip=Os fyddwch yn galluogi'r dewis hwn bydd y rhestr ceisiadau ddim yn cael ei glirio bob tro fyddwch yn symud i dudalen newydd
+
+# LOCALIZATION NOTE (netmonitor.toolbar.disableCache.label): This is the label
+# displayed for the checkbox for disabling browser cache.
+netmonitor.toolbar.disableCache.label=Analluogi'r storfa dros dro
+
+# LOCALIZATION NOTE (netmonitor.toolbar.disableCache.tooltip): This is the tooltip
+# displayed for the checkbox for disabling browser cache.
+netmonitor.toolbar.disableCache.tooltip=Analluogi storfa dros dro HTTP
+
+# LOCALIZATION NOTE (netmonitor.toolbar.clear): This is the label displayed
+# in the network toolbar for the "Clear" button.
+netmonitor.toolbar.clear=Clirio
+
+# LOCALIZATION NOTE (netmonitor.toolbar.toggleRecording): This is the label displayed
+# in the network toolbar for the toggle recording button.
+netmonitor.toolbar.toggleRecording=Oedi/Ailgychwyn recordio cofnod rhwydwaith
+
+# LOCALIZATION NOTE (netmonitor.toolbar.search): This is the tooltip label displayed
+# in the network toolbar for the search  button.
+netmonitor.toolbar.search=Chwilio
+
+# LOCALIZATION NOTE (netmonitor.toolbar.resetColumns): This is the label
+# displayed in the network table header context menu.
+netmonitor.toolbar.resetColumns=Ailosod Colofnau
+
+# LOCALIZATION NOTE (netmonitor.toolbar.resetSorting): This is the label
+# displayed in the network table header context menu to reset sorting
+netmonitor.toolbar.resetSorting=Ailosod Didoli
+
+# LOCALIZATION NOTE (netmonitor.toolbar.resizeColumnToFitContent): This is the label
+# displayed in the network table header context menu to resize a column to fit its content
+netmonitor.toolbar.resizeColumnToFitContent=Newid Maint Colofn I Ffitio'r Cynnwys
+
+# LOCALIZATION NOTE (netmonitor.toolbar.resizeColumnToFitContent.title): This is the title
+# tooltip displayed when draggable resizer in network table headers is hovered
+netmonitor.toolbar.resizeColumnToFitContent.title=Cliciwch ddwywaith i ffitio'r golofn i'r cynnwys
+
+# LOCALIZATION NOTE (netmonitor.toolbar.timings): This is the label
+# displayed in the network table header context menu for the timing submenu
+netmonitor.toolbar.timings=Amseru
+
+# LOCALIZATION NOTE (netmonitor.toolbar.responseHeaders): This is the
+# label displayed in the network table header context menu for the
+# response headers submenu.
+netmonitor.toolbar.responseHeaders=Penynnau Ymateb
+
+# LOCALIZATION NOTE (netmonitor.headers.toolbar.block): This is the
+# label displayed in the network details headers tab identifying the
+# block url toolbar button.
+netmonitor.headers.toolbar.block=Rhwystro
+
+# LOCALIZATION NOTE (netmonitor.headers.address): This is the label displayed
+# in the network details headers tab identifying the remote address.
+netmonitor.headers.address=Cyfeiriad
+
+# LOCALIZATION NOTE (netmonitor.headers.status): This is the label displayed
+# in the network details headers tab identifying the status code.
+netmonitor.headers.status=Statws
+
+# LOCALIZATION NOTE (netmonitor.headers.size): This is the label displayed
+# in the network details headers tab identifying the size.
+netmonitor.headers.size=Maint
+
+# LOCALIZATION NOTE (networkMenu.headers.sizeDetails): This label is displayed
+# in the network details headers tab providing the size details.
+# %1$S is the transferred size, %2$S is the size.
+netmonitor.headers.sizeDetails=%1$S (maint %2$S)
+
+# LOCALIZATION NOTE (netmonitor.headers.version): This is the label displayed
+# in the network details headers tab identifying the http version.
+netmonitor.headers.version=Fersiwn
+
+# LOCALIZATION NOTE (netmonitor.summary.learnMore): This is the label displayed
+# in the network details headers tab, with a link to external documentation for
+# status codes.
+netmonitor.summary.learnMore=Dysgu rhagor am god statws
+
+# LOCALIZATION NOTE (netmonitor.headers.referrerPolicy): This is the label displayed
+# in the network details headers tab identifying the referrer policy.
+netmonitor.headers.referrerPolicy=Polisi Cyfeiriwr:
+
+# LOCALIZATION NOTE (netmonitor.headers.contentBlocking): This is the label displayed
+# in the network details headers tab identifying the content blocking mode.
+netmonitor.headers.contentBlocking=Yn Rhwystro
+
+# LOCALIZATION NOTE (netmonitor.summary.editAndResend): This is the label displayed
+# on the button in the headers tab that opens a form to edit and resend the currently
+# displayed request
+netmonitor.summary.editAndResend=Golygu ac Ail anfon
+
+# LOCALIZATION NOTE (netmonitor.headers.raw): This is the label displayed
+# on the button in the headers tab that toggle view for raw request/response headers
+# from the currently displayed request
+netmonitor.headers.raw=Bras
+
+# LOCALIZATION NOTE (netmonitor.response.name): This is the label displayed
+# in the network details response tab identifying an image's file name.
+netmonitor.response.name=Enw:
+
+# LOCALIZATION NOTE (netmonitor.response.dimensions): This is the label displayed
+# in the network details response tab identifying an image's dimensions.
+netmonitor.response.dimensions=Maint:
+
+# LOCALIZATION NOTE (netmonitor.response.mime): This is the label displayed
+# in the network details response tab identifying an image's mime.
+netmonitor.response.mime=Math MIME:
+
+# LOCALIZATION NOTE (netmonitor.timings.blocked): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "blocked" state.
+netmonitor.timings.blocked=Rhwystrwyd:
+
+# LOCALIZATION NOTE (netmonitor.timings.dns): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "dns" state.
+netmonitor.timings.dns=Cydraniad DNS:
+
+# LOCALIZATION NOTE (netmonitor.timings.ssl): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "tls" handshake state.
+netmonitor.timings.ssl=Gosodiad TLS:
+
+# LOCALIZATION NOTE (netmonitor.timings.connect): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "connect" state.
+netmonitor.timings.connect=Cysylltu:
+
+# LOCALIZATION NOTE (netmonitor.timings.send): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "send" state.
+netmonitor.timings.send=Anfon:
+
+# LOCALIZATION NOTE (netmonitor.timings.wait): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "wait" state.
+netmonitor.timings.wait=Aros:
+
+# LOCALIZATION NOTE (netmonitor.timings.receive): This is the label displayed
+# in the network details timings tab identifying the amount of time spent
+# in a "receive" state.
+netmonitor.timings.receive=Derbyn:
+
+# LOCALIZATION NOTE (netmonitor.timings.learnMore): This is the label displayed
+# in the network details timings tab, with a link to external documentation
+netmonitor.timings.learnMore=Dysgu rhagor am amseru
+
+# LOCALIZATION NOTE (netmonitor.audits.slowIconTooltip): This is the tooltip text displayed
+# in the network request list file column, on the slow icon button.
+# %1$S is the waiting time %2$S is the slow threshold.
+netmonitor.audits.slowIconTooltip=Amser ymateb gweinydd araf (%1$S). Y terfyn sy'n cael ei argymell yw %2$S
+
+# LOCALIZATION NOTE (netmonitor.security.warning.cipher): A tooltip
+# for warning icon that indicates a connection uses insecure cipher suite.
+netmonitor.security.warning.cipher=Mae'r seiffr sy'n cael ei ddefnyddio ar gyfer amgryptio yn anghymeradwy ac anniogel.
+
+# LOCALIZATION NOTE (netmonitor.security.error): This is the label displayed
+# in the security tab if a security error prevented the connection.
+netmonitor.security.error=Digwyddodd gwall:
+
+# LOCALIZATION NOTE (netmonitor.security.protocolVersion): This is the label displayed
+# in the security tab describing TLS/SSL protocol version.
+netmonitor.security.protocolVersion=Fersiwn y protocol:
+
+# LOCALIZATION NOTE (netmonitor.security.cipherSuite): This is the label displayed
+# in the security tab describing the cipher suite used to secure this connection.
+netmonitor.security.cipherSuite=Casgliad seiffer:
+
+# LOCALIZATION NOTE (netmonitor.security.keaGroup): This is the label displayed
+# in the security tab describing the key exchange group suite used to secure
+# this connection.
+netmonitor.security.keaGroup=Grŵp Cyfnewid Allwedd:
+
+# LOCALIZATION NOTE (netmonitor.security.keaGroup.none): This is the label
+# displayed in the security tab describing the case when no group was used.
+netmonitor.security.keaGroup.none=dim
+
+# LOCALIZATION NOTE (netmonitor.security.keaGroup.custom): This is the label
+# displayed in the security tab describing the case when a custom group was used.
+netmonitor.security.keaGroup.custom=cyfaddasu
+
+# LOCALIZATION NOTE (netmonitor.security.keaGroup.unknown): This is the value
+# displayed in the security tab describing an unknown group.
+netmonitor.security.keaGroup.unknown=grŵp anhysbys
+
+# LOCALIZATION NOTE (netmonitor.security.signatureScheme): This is the label
+# displayed in the security tab describing the signature scheme used by for
+# the server certificate in this connection.
+netmonitor.security.signatureScheme=Cynllun Llofnod:
+
+# LOCALIZATION NOTE (netmonitor.security.signatureScheme.none): This is the
+# label displayed in the security tab describing the case when no signature
+# was used.
+netmonitor.security.signatureScheme.none=dim
+
+# LOCALIZATION NOTE (netmonitor.security.signatureScheme.unknown): This is the
+# value displayed in the security tab describing an unknown signature scheme.
+netmonitor.security.signatureScheme.unknown=cynllun llofnod anhysbys
+
+# LOCALIZATION NOTE (netmonitor.security.hsts): This is the label displayed
+# in the security tab describing the usage of HTTP Strict Transport Security.
+netmonitor.security.hsts=Diogelwch Trosglwyddo Llym HTTP:
+
+# LOCALIZATION NOTE (netmonitor.security.hpkp): This is the label displayed
+# in the security tab describing the usage of Public Key Pinning.
+netmonitor.security.hpkp=Pinio Allwedd Gyhoeddus:
+
+# LOCALIZATION NOTE (netmonitor.security.connection): This is the label displayed
+# in the security tab describing the section containing information related to
+# the secure connection.
+netmonitor.security.connection=Cysylltiad:
+
+# LOCALIZATION NOTE (netmonitor.security.certificate): This is the label displayed
+# in the security tab describing the server certificate section.
+netmonitor.security.certificate=Tystysgrif:
+
+# LOCALIZATION NOTE (netmonitor.trackingResource.tooltip): This is the label used
+# in the Network monitor panel as a tooltip for tracking resource icon.
+netmonitor.trackingResource.tooltip=Mae'r URL hwn yn cyfateb i draciwr hysbys a fyddai'n cael ei rwystro gyda Rhwystro Cynnwys ymlaen.
+
+# LOCALIZATION NOTE (netmonitor.trackingResource.enhancedTrackingProtection): This is
+# the label used in the Network monitor panel for showing enhanced tracking protection.
+netmonitor.trackingResource.enhancedTrackingProtection=Diogelwch Uwch Rhag Tracio
+
+# LOCALIZATION NOTE (netmonitor.enhancedTrackingProtection.learnMore): This is the label
+# displayed in the network details headers tab, with a link to external documentation for
+# enhanced tracking protection.
+netmonitor.enhancedTrackingProtection.learnMore=Dysgu rhagor am ddiogelwch tracio uwch
+
+# LOCALIZATION NOTE (netmonitor.context.copy): This is the label displayed
+# for the copy sub-menu in the context menu for a request
+netmonitor.context.copy=Copïo
+
+# LOCALIZATION NOTE (netmonitor.context.copy.accesskey): This is the access key
+# for the copy menu/sub-menu displayed in the context menu for a request
+netmonitor.context.copy.accesskey=C
+
+# LOCALIZATION NOTE (netmonitor.context.copyUrl): This is the label displayed
+# on the context menu that copies the selected request's url
+netmonitor.context.copyUrl=Copïo URL
+
+# LOCALIZATION NOTE (netmonitor.context.copyUrl.accesskey): This is the access key
+# for the Copy URL menu item displayed in the context menu for a request
+netmonitor.context.copyUrl.accesskey=U
+
+# LOCALIZATION NOTE (netmonitor.context.copyUrlParams): This is the label displayed
+# on the context menu that copies the selected request's url parameters
+netmonitor.context.copyUrlParams=Copïo Paramedrau URL
+
+# LOCALIZATION NOTE (netmonitor.context.copyUrlParams.accesskey): This is the access key
+# for the Copy URL Parameters menu item displayed in the context menu for a request
+netmonitor.context.copyUrlParams.accesskey=P
+
+# LOCALIZATION NOTE (netmonitor.context.copyRequestData): This is the label displayed
+# on the context menu that copies the selected request's data
+netmonitor.context.copyRequestData=Copïo Data %S
+
+# LOCALIZATION NOTE (netmonitor.context.copyRequestData.accesskey): This is the access key
+# for the Copy POST/PATCH/PUT/DELETE Data menu item displayed in the context menu for a request
+netmonitor.context.copyRequestData.accesskey=D
+
+# LOCALIZATION NOTE (netmonitor.context.copyAsCurl): This is the label displayed
+# on the context menu that copies the selected request as a cURL command.
+# The capitalization is part of the official name and should be used throughout all languages.
+# http://en.wikipedia.org/wiki/CURL
+netmonitor.context.copyAsCurl=Copïo fel cURL
+
+# LOCALIZATION NOTE (netmonitor.context.copyAsCurl.accesskey): This is the access key
+# for the Copy as cURL menu item displayed in the context menu for a request
+netmonitor.context.copyAsCurl.accesskey=C
+
+# LOCALIZATION NOTE (netmonitor.context.copyAsCurl.*): This is the template used to add
+# a target platform to the label for "Copy as cURL" command
+# e.g. Copy as cURL (Windows)
+# Localized label for "Copy as cURL": %S
+netmonitor.context.copyAsCurl.win=%S (Windows)
+netmonitor.context.copyAsCurl.win.accesskey=W
+netmonitor.context.copyAsCurl.posix=%S (POSIX)
+netmonitor.context.copyAsCurl.posix.accesskey=P
+
+# LOCALIZATION NOTE (netmonitor.context.copyAsFetch): This is the label displayed
+# on the context menu that copies the selected request as a fetch request.
+netmonitor.context.copyAsFetch=Copïo fel Fetch
+
+# LOCALIZATION NOTE (netmonitor.context.copyAsFetch.accesskey): This is the access key
+# for the Copy as fetch menu item displayed in the context menu for a request
+netmonitor.context.copyAsFetch.accesskey=F
+
+# LOCALIZATION NOTE (netmonitor.context.copyRequestHeaders): This is the label displayed
+# on the context menu that copies the selected item's request headers
+netmonitor.context.copyRequestHeaders=Copïo'r Penynnau Gofyn
+
+# LOCALIZATION NOTE (netmonitor.context.copyRequestHeaders.accesskey): This is the access key
+# for the Copy Request Headers menu item displayed in the context menu for a request
+netmonitor.context.copyRequestHeaders.accesskey=P
+
+# LOCALIZATION NOTE (netmonitor.context.copyResponseHeaders): This is the label displayed
+# on the context menu that copies the selected item's response headers
+netmonitor.context.copyResponseHeaders=Copïo Penynnau Ymateb
+
+# LOCALIZATION NOTE (netmonitor.context.copyResponseHeaders.accesskey): This is the access key
+# for the Copy Response Headers menu item displayed in the context menu for a response
+netmonitor.context.copyResponseHeaders.accesskey=P
+
+# LOCALIZATION NOTE (netmonitor.context.copyResponse): This is the label displayed
+# on the context menu that copies the selected response as a string
+netmonitor.context.copyResponse=Copïo'r Ymateb
+
+# LOCALIZATION NOTE (netmonitor.context.copyResponse.accesskey): This is the access key
+# for the Copy Response menu item displayed in the context menu for a request
+netmonitor.context.copyResponse.accesskey=R
+
+# LOCALIZATION NOTE (netmonitor.context.copyImageAsDataUri): This is the label displayed
+# on the context menu that copies the selected image as data uri
+netmonitor.context.copyImageAsDataUri=Copïo Delwedd fel Data URI
+
+# LOCALIZATION NOTE (netmonitor.context.copyImageAsDataUri.accesskey): This is the access key
+# for the Copy Image As Data URI menu item displayed in the context menu for a request
+netmonitor.context.copyImageAsDataUri.accesskey=I
+
+# LOCALIZATION NOTE (netmonitor.context.useAsFetch): This is the label displayed
+# on the context menu that copies the selected request as a fetch command.
+netmonitor.context.useAsFetch=Defnyddio fel Fetch i=yn y Consol
+
+# LOCALIZATION NOTE (netmonitor.context.useAsFetch.accesskey): This is the access key
+# for the Copy as fetch menu item displayed in the context menu for a request
+netmonitor.context.useAsFetch.accesskey=F
+
+# LOCALIZATION NOTE (netmonitor.context.saveImageAs): This is the label displayed
+# on the context menu that save the Image
+netmonitor.context.saveImageAs=Cadw Delwedd Fel
+
+# LOCALIZATION NOTE (netmonitor.context.saveImageAs.accesskey): This is the access key
+# for the Copy Image As Data URI menu item displayed in the context menu for a request
+netmonitor.context.saveImageAs.accesskey=D
+
+# LOCALIZATION NOTE (netmonitor.context.copyAll): This is the label displayed
+# on the context menu that copies all data
+netmonitor.context.copyAll=Copïo Popeth
+
+# LOCALIZATION NOTE (netmonitor.context.copyAll.accesskey): This is the access key
+# for the Copy All menu item displayed in the context menu for a properties view panel
+netmonitor.context.copyAll.accesskey=P
+
+# LOCALIZATION NOTE (netmonitor.context.copyAllAsHar): This is the label displayed
+# on the context menu that copies all as HAR format
+netmonitor.context.copyAllAsHar=Copïo Popeth fel HAR
+
+# LOCALIZATION NOTE (netmonitor.context.copyAllAsHar.accesskey): This is the access key
+# for the Copy All As HAR menu item displayed in the context menu for a network panel
+netmonitor.context.copyAllAsHar.accesskey=O
+
+# LOCALIZATION NOTE (netmonitor.context.saveAllAsHar): This is the label displayed
+# on the context menu that saves all as HAR format
+netmonitor.context.saveAllAsHar=Cadw Popeth fel HAR
+
+# LOCALIZATION NOTE (netmonitor.context.saveAllAsHar.accesskey): This is the access key
+# for the Save All As HAR menu item displayed in the context menu for a network panel
+netmonitor.context.saveAllAsHar.accesskey=H
+
+# LOCALIZATION NOTE (netmonitor.context.importHar.accesskey): This is the access key
+# for the Import HAR menu item displayed in the context menu for a network panel
+netmonitor.context.importHar.accesskey=M
+
+# LOCALIZATION NOTE (netmonitor.har.importHarDialogTitle): This is a label
+# used for import file open dialog
+netmonitor.har.importHarDialogTitle=Mewnforio Ffeil HAR
+
+# LOCALIZATION NOTE (netmonitor.har.importDialogHARFilter):
+# This string is displayed as a filter for importing HAR file
+netmonitor.har.importDialogHARFilter=Ffeiliau HAR
+
+# LOCALIZATION NOTE (netmonitor.har.importDialogAllFilter):
+# This string is displayed as a filter for importing HAR file
+netmonitor.har.importDialogAllFilter=Pob Ffeil
+
+# LOCALIZATION NOTE (netmonitor.context.resend.label): This is the label displayed
+# on the context menu that resends the currently displayed request immediately
+netmonitor.context.resend.label=Ail anfon
+
+# LOCALIZATION NOTE (netmonitor.context.resend.accesskey): This is the access key
+# for the "Resend" menu item displayed in the context menu for a request
+netmonitor.context.resend.accesskey=a
+
+# LOCALIZATION NOTE (netmonitor.context.editAndResend): This is the label displayed
+# on the context menu that opens a form to edit and resend the currently
+# displayed request
+netmonitor.context.editAndResend=Golygu ac Ail anfon
+
+# LOCALIZATION NOTE (netmonitor.context.editAndResend.accesskey): This is the access key
+# for the "Edit and Resend" menu item displayed in the context menu for a request
+netmonitor.context.editAndResend.accesskey=G
+
+# LOCALIZATION NOTE (netmonitor.context.blockURL): This is the label displayed
+# on the context menu that blocks any requests matching the selected request's URL.
+netmonitor.context.blockURL=Rhwystro URL
+
+# LOCALIZATION NOTE (netmonitor.context.unblockURL): This is the label displayed
+# on the context menu that unblocks any requests matching the selected request's URL.
+netmonitor.context.unblockURL=Dad-rwystro URL
+
+# LOCALIZATION NOTE (netmonitor.context.newTab):  This is the label
+# for the Open in New Tab menu item displayed in the context menu of the
+# network container
+netmonitor.context.newTab=Agor mewn Tab Newydd
+
+# LOCALIZATION NOTE (netmonitor.context.newTab.accesskey): This is the access key
+# for the Open in New Tab menu item displayed in the context menu of the
+# network container
+netmonitor.context.newTab.accesskey=T
+
+# LOCALIZATION NOTE (netmonitor.context.openInDebugger):  This is the label
+# for the Open in Debugger menu item displayed in the context menu of the
+# network container
+netmonitor.context.openInDebugger=Agor yn y Dadfygiwr
+
+# LOCALIZATION NOTE (netmonitor.context.openInDebugger.accesskey): This is the access key
+# for the Open in Debugger menu item displayed in the context menu of the
+# network container
+netmonitor.context.openInDebugger.accesskey=D
+
+# LOCALIZATION NOTE (netmonitor.context.openInStyleEditor):  This is the label
+# for the Open in Style Editor menu item displayed in the context menu of the
+# network container
+netmonitor.context.openInStyleEditor=Agor yn y Golygydd Arddull
+
+# LOCALIZATION NOTE (netmonitor.context.openInStyleEditor.accesskey): This is
+# the access key for the Open in Style Editor menu item displayed in the
+# context menu of the network container
+netmonitor.context.openInStyleEditor.accesskey=A
+
+# LOCALIZATION NOTE (netmonitor.context.perfTools): This is the label displayed
+# on the context menu that shows the performance analysis tools
+netmonitor.context.perfTools=Cychwyn Dadansoddi Perfformiad…
+
+# LOCALIZATION NOTE (netmonitor.context.perfTools.accesskey): This is the access key
+# for the performance analysis menu item displayed in the context menu for a request
+netmonitor.context.perfTools.accesskey=A
+
+# LOCALIZATION NOTE (netmonitor.custom.newRequest): This is the label displayed
+# as the title of the new custom request form
+netmonitor.custom.newRequest=Cais Newydd
+
+# LOCALIZATION NOTE (netmonitor.custom.newRequestMethodLabel): This is the label displayed
+# above the method text input field of the new custom request form
+netmonitor.custom.newRequestMethodLabel=Dull
+
+# LOCALIZATION NOTE (netmonitor.custom.newRequestUrlLabel): This is the label displayed
+# above the url text input field of the new custom request form
+netmonitor.custom.newRequestUrlLabel=URL
+
+# LOCALIZATION NOTE (netmonitor.custom.query): This is the label displayed
+# above the query string entry in the custom request form
+netmonitor.custom.query=Llinyn Ymholi:
+
+# LOCALIZATION NOTE (netmonitor.custom.headers): This is the label displayed
+# above the request headers entry in the custom request form
+netmonitor.custom.headers=Pennyn Gofyn:
+
+# LOCALIZATION NOTE (netmonitor.custom.postData): This is the label displayed
+# above the request body entry in the custom request form
+netmonitor.custom.postData=Corff sy'n Gofyn:
+
+# LOCALIZATION NOTE (netmonitor.custom.send): This is the label displayed
+# on the button which sends the custom request
+netmonitor.custom.send=Anfon
+
+# LOCALIZATION NOTE (netmonitor.custom.cancel): This is the label displayed
+# on the button which cancels and closes the custom request form
+netmonitor.custom.cancel=Diddymu
+
+# LOCALIZATION NOTE (netmonitor.backButton): This is the label displayed
+# on the button which exists the performance statistics view
+netmonitor.backButton=Nôl
+
+# LOCALIZATION NOTE (netmonitor.status.tooltip.simple): This is the tooltip of the
+# column status code, when request is not being cached or is not from a service worker
+# %1$S is the status code, %2$S is the status text.
+netmonitor.status.tooltip.simple = %1$S %2$S
+
+# LOCALIZATION NOTE (netmonitor.status.tooltip.cached): This is the tooltip of
+# the column status code, when the request is cached
+# %1$S is the status code, %2$S is the status text.
+netmonitor.status.tooltip.cached = %1$S %2$S (wedi ei storio dros dro)
+
+# LOCALIZATION NOTE (netmonitor.status.tooltip.worker): This is the tooltip of
+# the column status code, when the request is from a service worker
+# %1$S is the status code, %2$S is the status text.
+netmonitor.status.tooltip.worker = %1$S %2$S (gweithiwr gwasanaeth)
+
+# LOCALIZATION NOTE (netmonitor.status.tooltip.cachedworker): This is the tooltip
+# of the column status code, when the request is cached and is from a service worker
+# %1$S is the status code, %2$S is the status text.
+netmonitor.status.tooltip.cachedworker = %1$S %2$S (wedi ei storio dros dro, gweithiwr gwasanaeth)
+
+# LOCALIZATION NOTE (netmonitor.label.dropHarFiles): This is a label
+# rendered within the Network panel when *.har file(s) are dragged
+# over the content.
+netmonitor.label.dropHarFiles = Gollwng ffeiliau HAR yma
+
+# LOCALIZATION NOTE (netmonitor.label.har): This is a label used
+# as a tooltip for toolbar drop-down button with HAR actions
+netmonitor.label.har=Allforio/Mewnforio HAR
+
+# LOCALIZATION NOTE (netmonitor.cache.cache): This is the label text for the parent
+# node in the TreeView.
+netmonitor.cache.cache=Storfa Dros Dro
+
+# LOCALIZATION NOTE (netmonitor.cache.empty): This is the text displayed when cache
+# information is not available.
+netmonitor.cache.empty=Dim gwybodaeth am y storfa dros dro
+
+# LOCALIZATION NOTE (netmonitor.cache.notAvailable): This is the text displayed under
+# a node that has no information available.
+netmonitor.cache.notAvailable=Dim ar gael
+
+# LOCALIZATION NOTE (netmonitor.cache.dataSize): This is the label text for
+# the datasize of the cached object.
+netmonitor.cache.dataSize=Maint Data
+
+# LOCALIZATION NOTE (netmonitor.cache.expires): This is the label text for the
+# expires time of the cached object.
+netmonitor.cache.expires=Daw i ben
+
+# LOCALIZATION NOTE (netmonitor.cache.fetchCount): This is the label text for the
+# fetch count of the cached object.
+netmonitor.cache.fetchCount=Cyfrif Estyn
+
+# LOCALIZATION NOTE (netmonitor.cache.lastFetched): This is the label text for the
+# last fetched date/time of the cached object.
+netmonitor.cache.lastFetched=Estynnwyd Diwethaf
+
+# LOCALIZATION NOTE (netmonitor.cache.lastModified): This is the label text for the
+# last modified date/time of the cached object.
+netmonitor.cache.lastModified=Newidiwyd Diwethaf
+
+# LOCALIZATION NOTE (netmonitor.cache.device): This is the label text for the device
+# where a cached object was fetched from (e.g. "disk").
+netmonitor.cache.device=Dyfais
+
+# LOCALIZATION NOTE (netmonitor.settings.menuTooltip): This is the tooltip that gets displayed
+# when the settings menu button is hovered.
+netmonitor.settings.menuTooltip=Gosodiadau Rhwydwaith
+
+# LOCALIZATION NOTE (netmonitor.settings.importHarTooltip): This is the tooltip that gets displayed
+# when the HAR import menu item is hovered
+netmonitor.settings.importHarTooltip=Mewnforio ffeil HAR o ddata rhwydwaith
+
+# LOCALIZATION NOTE (netmonitor.settings.saveHarTooltip): This is the tooltip that gets displayed
+# when the HAR save menu item is hovered
+netmonitor.settings.saveHarTooltip=Cadw data rhwydwaith i ffeil HAR
+
+# LOCALIZATION NOTE (netmonitor.settings.copyHarTooltip): This is the tooltip that gets displayed
+# when the HAR copy menu item is hovered
+netmonitor.settings.copyHarTooltip=Copïo data rhwydwaith i'r clipfwrdd
+
+# LOCALIZATION NOTE (netmonitor.errorpanel.description): This is the information displayed once the monitor errors out
+netmonitor.errorpanel.description=Mae'r panel Rhwydwaith wedi chwalu.
+
+# LOCALIZATION NOTE (netmonitor.errorpanel.fileBugButton): This is the text that appears in the button to visit the bug filing link.
+netmonitor.errorpanel.fileBugButton=Lluniwch Adroddiad Gwall
+
+# LOCALIZATION NOTE (netmonitor.errorpanel.reloadPanelInfo): This is the text that appears after Network panel errors to instruct the user to reload the panel.
+netmonitor.errorpanel.reloadPanelInfo=Caewch ac ailagor y blwch offer i glirio'r gwall hwn.
diff --git a/l10n-cy/devtools/client/network-throttling.properties b/l10n-cy/devtools/client/network-throttling.properties
new file mode 100644
index 0000000000..ce910a28cd
--- /dev/null
+++ b/l10n-cy/devtools/client/network-throttling.properties
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the NetworkThrottlingSelector
+# component used to throttle network bandwidth.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE These strings are used inside the NetworkThrottlingMenu
+# component used to throttle network bandwidth.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (responsive.noThrottling): UI option in a menu to configure
+# network throttling.  This option is the default and disables throttling so you
+# just have normal network conditions.  There is not very much room in the UI
+# so a short string would be best if possible.
+responsive.noThrottling=Dim cyfyngu
diff --git a/l10n-cy/devtools/client/performance.dtd b/l10n-cy/devtools/client/performance.dtd
new file mode 100644
index 0000000000..ea1b52eaa3
--- /dev/null
+++ b/l10n-cy/devtools/client/performance.dtd
@@ -0,0 +1,136 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE : FILE This file contains the Performance strings -->
+<!-- LOCALIZATION NOTE : FILE Do not translate commandkey -->
+
+<!-- LOCALIZATION NOTE : FILE The correct localization of this file might be to
+  - keep it in English, or another language commonly spoken among web developers.
+  - You want to make that choice consistent across the developer tools.
+  - A good criteria is the language in which you'd find the best
+  - documentation on web development on the web. -->
+<!-- LOCALIZATION NOTE (performanceUI.bufferStatusTooltip): This string
+  -  is displayed as the tooltip for the buffer capacity during a recording. -->
+
+
+
+<!ENTITY performanceUI.bufferStatusTooltip "Mae'r proffiliwr yn cadw samplau mewn byffer cylchol ac unwaith mae'r byffer yn cyrraedd y terfyn ar gyfer recordiad, bydd samplau newydd yn cychwyn trosysgrifennu samplau ar gychwyn recordiad.">
+<!-- LOCALIZATION NOTE (performanceUI.disabledRealTime.nonE10SBuild): This string
+  -  is displayed as a message for why the real time overview graph is disabled
+  -  when running on a non-multiprocess build. -->
+
+<!-- LOCALIZATION NOTE (performanceUI.disabledRealTime.disabledE10S): This string
+  -  is displayed as a message for why the real time overview graph is disabled
+  -  when running on a build that can run multiprocess Firefox, but just is not enabled. -->
+
+<!ENTITY performanceUI.disabledRealTime.disabledE10S "Galluogi Firefox amlbroses yn y dewisiadau ar gyfer cynhyrchu data recordio mewn gwir amser.">
+<!-- LOCALIZATION NOTE (performanceUI.bufferStatusFull): This string
+  -  is displayed when the profiler's circular buffer has started to overlap. -->
+
+<!ENTITY performanceUI.bufferStatusFull "Mae'r byffer yn llawn. Mae hen samplau nawr yn cael eu trosysgrifennu.">
+<!-- LOCALIZATION NOTE (performanceUI.loadingNotice): This is the label shown
+  -  in the details view while the profiler is unavailable, for example, while
+  -  in Private Browsing mode. -->
+
+<!ENTITY performanceUI.unavailableNoticePB "Nid yw recordio proffil ar gael ar hyn o bryd. Caewch bob ffenestr pori breifat a cheisio eto.">
+<!-- LOCALIZATION NOTE (performanceUI.loadingNotice): This is the label shown
+  -  in the details view while loading a profile. -->
+
+<!ENTITY performanceUI.loadingNotice "Llwytho…">
+<!-- LOCALIZATION NOTE (performanceUI.toolbar.*): These strings are displayed
+  -  in the toolbar on buttons that select which view is currently shown. -->
+
+<!ENTITY performanceUI.toolbar.waterfall "Rhaeadr">
+<!ENTITY performanceUI.toolbar.waterfall.tooltiptext "Dangos y gwananol weithredoedd mae'r porwr yn eu gwneud wrth recordio, wedi eu gosod allan yn eu tro ac fel rhaeadr.">
+<!ENTITY performanceUI.toolbar.js-calltree "Coeden Alw">
+<!ENTITY performanceUI.toolbar.js-calltree.tooltiptext "Amlygu swyddogaethau JavaScript lle mae'r porwr yn treulio rhan fwyaf o'i amser yn ystod y recordiad.">
+<!ENTITY performanceUI.toolbar.memory-calltree "Dynodiadau">
+<!ENTITY performanceUI.toolbar.allocations.tooltiptext "Dangos lle mae'r cof wedi ei neilltuo yn ystod y recordio.">
+<!ENTITY performanceUI.toolbar.js-flamegraph "Siart Fflam JS">
+<!ENTITY performanceUI.toolbar.js-flamegraph.tooltiptext "Dangos y pentwr galw JavaScript yn ystod y recordiad.">
+<!ENTITY performanceUI.toolbar.memory-flamegraph "Siart Fflam Dynodiadau">
+<!-- LOCALIZATION NOTE (performanceUI.table.*): These strings are displayed
+  -  in the call tree headers for a recording. -->
+
+<!ENTITY performanceUI.table.totalDuration            "Cyfanswm Amser">
+<!ENTITY performanceUI.table.totalDuration.tooltip    "Maint yr amser sy'n cael ei dreulio yn y swyddogaeth yma a'r swyddogaethau mae'n eu galw.">
+<!ENTITY performanceUI.table.selfDuration             "Eich Amser Chi">
+<!ENTITY performanceUI.table.selfDuration.tooltip     "Y maint o amser a dreuliwyd dim ond gyda'r swyddogaeth hon.">
+<!ENTITY performanceUI.table.totalPercentage          "Cyfanswm Cost">
+<!ENTITY performanceUI.table.totalPercentage.tooltip  "Maint yr amser sy'n cael ei dreulio yn y swyddogaeth yma a'r swyddogaethau mae'n eu galw.">
+<!ENTITY performanceUI.table.selfPercentage           "Cost Hunan">
+<!ENTITY performanceUI.table.selfPercentage.tooltip   "Canran yr amser sy'n cael ei dreulio dim ond o fewn y swyddogaeth yma.">
+<!ENTITY performanceUI.table.samples                  "Samplau">
+<!ENTITY performanceUI.table.samples.tooltip          "Y nifer o weithiau fu'r swyddogaeth ar y stac pan gymrodd y proffil sampl.">
+<!ENTITY performanceUI.table.function                 "Ffwythiant">
+<!ENTITY performanceUI.table.function.tooltip         "Enw a lleoliad ffynhonnell y swyddogaeth sampledig.">
+<!ENTITY performanceUI.table.totalAlloc               "Cyfanswm Dynodiadau Samplwyd">
+<!ENTITY performanceUI.table.totalAlloc.tooltip       "Cyfanswm y nifer o ddynodiadau Gwrthrych samplwyd yn y lleoliad hwn a'i alwadwyr.">
+<!-- LOCALIZATION NOTE (performanceUI.options.filter.tooltiptext): This string
+  -  is displayed next to the filter button-->
+
+<!ENTITY performanceUI.options.filter.tooltiptext "Dewiswch pa ddata i'w ddangos yn y llinell amser">
+<!-- LOCALIZATION NOTE (performanceUI.options.gear.tooltiptext): This is the
+  -  tooltip for the options button. -->
+
+<!ENTITY performanceUI.options.gear.tooltiptext "Ffurfweddu'r dewisiadau perfformiad.">
+<!-- LOCALIZATION NOTE (performanceUI.invertTree): This is the label shown next to
+  -  a checkbox that inverts and un-inverts the profiler's call tree. -->
+
+<!ENTITY performanceUI.invertTree             "Gwrthdroi'r Goeden Alw">
+<!ENTITY performanceUI.invertTree.tooltiptext "Bydd gwrthdroi'r goeden alw'n dangos y llwybrau galw proffwyd gan gychwyn o'r fframiau ieuengaf ac ehangu i'r fframiau hŷn.">
+<!-- LOCALIZATION NOTE (performanceUI.invertFlameGraph): This is the label shown next to
+  -  a checkbox that inverts and un-inverts the profiler's flame graph. -->
+
+<!ENTITY performanceUI.invertFlameGraph             "Gwrthdroi'r Siart Fflam">
+<!ENTITY performanceUI.invertFlameGraph.tooltiptext "Bydd gwrthdroi'r siart fflam yn dangos y llwybrau galw proffilwyd gan gychwyn o'r fframiau ieuengaf ac ehangu i'r fframiau hŷn.">
+<!-- LOCALIZATION NOTE (performanceUI.showPlatformData): This is the
+  -  label for the checkbox that toggles whether or not Gecko platform data
+  -  is displayed in the profiler. -->
+
+<!ENTITY performanceUI.showPlatformData             "Dangos Data Platfform Gecko">
+<!ENTITY performanceUI.showPlatformData.tooltiptext "Mae dangos data'r platfform yn galluogi adroddiadau Proffiliwr JavaScript i gynnwys symbolau platfform Gecko.">
+<!-- LOCALIZATION NOTE (performanceUI.showJITOptimizations): This string
+  -  is displayed next to a checkbox determining whether or not JIT optimization data
+  -  should be displayed. -->
+
+<!ENTITY performanceUI.showJITOptimizations             "Dangos Optimeiddiadau JIT">
+<!ENTITY performanceUI.showJITOptimizations.tooltiptext "Dangos optimeiddiadau data JIT samplwyd ym mhob ffrâm JavaScript.">
+<!-- LOCALIZATION NOTE (performanceUI.flattenTreeRecursion): This is the
+  -  label for the checkbox that toggles the flattening of tree recursion in inspected
+  -  functions in the profiler. -->
+
+<!ENTITY performanceUI.flattenTreeRecursion             "Gwastatau Dychweliad Coeden">
+<!ENTITY performanceUI.flattenTreeRecursion.tooltiptext "Gwastatau dychweliadau wrth archwilio swyddogaethau.">
+<!-- LOCALIZATION NOTE (performanceUI.enableMemory): This string
+  -  is displayed next to a checkbox determining whether or not memory
+  -  measurements are enabled. -->
+
+<!ENTITY performanceUI.enableMemory             "Cofnodi Cof">
+<!ENTITY performanceUI.enableMemory.tooltiptext "Cofnodi'r defnydd o'r cof wrth broffilio.">
+<!-- LOCALIZATION NOTE (performanceUI.enableAllocations): This string
+  -  is displayed next to a checkbox determining whether or not allocation
+  -  measurements are enabled. -->
+
+<!ENTITY performanceUI.enableAllocations             "Dyraniad Cofnodion">
+<!ENTITY performanceUI.enableAllocations.tooltiptext "Cofnodi dyraniad Gwrthrych Cofnodi wrth broffilio.">
+<!-- LOCALIZATION NOTE (performanceUI.enableFramerate): This string
+  -  is displayed next to a checkbox determining whether or not framerate
+  -  is recorded. -->
+
+<!ENTITY performanceUI.enableFramerate             "Cofnodi'r graddfa fframio">
+<!ENTITY performanceUI.enableFramerate.tooltiptext "Cofnodi'r raddfa fframio wrth broffilio.">
+<!-- LOCALIZATION NOTE (performanceUI.console.recordingNoticeStart/recordingNoticeEnd):
+  -  This string is displayed when a recording is selected that started via console.profile.
+  -  Wraps the command used to start, like "Currently recording via console.profile("label")" -->
+
+<!ENTITY performanceUI.console.recordingNoticeStart "Wrthi'n recordio drwy">
+<!ENTITY performanceUI.console.recordingNoticeEnd   "">
+<!-- LOCALIZATION NOTE (performanceUI.console.stopCommandStart/stopCommandEnd):
+  -  This string is displayed when a recording is selected that started via console.profile.
+  -  Indicates how to stop the recording, wrapping the command, like
+  -  "Stop recording by entering console.profileEnd("label") into the console." -->
+
+<!ENTITY performanceUI.console.stopCommandStart "Atal recordio drwy gyflwyno">
+<!ENTITY performanceUI.console.stopCommandEnd   "i'r consol.">
diff --git a/l10n-cy/devtools/client/performance.properties b/l10n-cy/devtools/client/performance.properties
new file mode 100644
index 0000000000..95a599322e
--- /dev/null
+++ b/l10n-cy/devtools/client/performance.properties
@@ -0,0 +1,160 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Performance Tools
+# which is available from the Web Developer sub-menu -> 'Performance'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (noRecordingsText): The text to display in the
+# recordings menu when there are no recorded profiles yet.
+noRecordingsText=Nid oes proffiliau eto.
+
+# LOCALIZATION NOTE (recordingsList.itemLabel):
+# This string is displayed in the recordings list of the Performance Tools,
+# identifying a set of function calls. %S represents the number of recording,
+# iterating for every new recording, resulting in "Recording #1", "Recording #2", etc.
+recordingsList.itemLabel=Recordio #%S
+
+# LOCALIZATION NOTE (recordingsList.recordingLabel):
+# This string is displayed in the recordings list of the Performance Tools,
+# for an item that has not finished recording.
+recordingsList.recordingLabel=Cynnydd…
+
+# LOCALIZATION NOTE (recordingsList.loadingLabel):
+# This string is displayed in the recordings list of the Performance Tools,
+# for an item that is finished and is loading.
+recordingsList.loadingLabel=Llwytho…
+
+# LOCALIZATION NOTE (recordingsList.durationLabel):
+# This string is displayed in the recordings list of the Performance Tools,
+# for an item that has finished recording.
+recordingsList.durationLabel=%S ms
+
+# LOCALIZATION NOTE (recordingsList.saveLabel):
+# This string is displayed in the recordings list of the Performance Tools,
+# for saving an item to disk.
+recordingsList.saveLabel=Cadw
+
+# LOCALIZATION NOTE (graphs.fps):
+# This string is displayed in the framerate graph of the Performance Tools,
+# as the unit used to measure frames per second. This label should be kept
+# AS SHORT AS POSSIBLE so it doesn't obstruct important parts of the graph.
+graphs.fps=ff/e
+
+# LOCALIZATION NOTE (graphs.ms):
+# This string is displayed in the flamegraph of the Performance Tools,
+# as the unit used to measure time (in milliseconds). This label should be kept
+# AS SHORT AS POSSIBLE so it doesn't obstruct important parts of the graph.
+graphs.ms=ms
+
+# LOCALIZATION NOTE (graphs.memory):
+# This string is displayed in the memory graph of the Performance tool,
+# as the unit used to memory consumption. This label should be kept
+# AS SHORT AS POSSIBLE so it doesn't obstruct important parts of the graph.
+graphs.memory=MB
+
+# LOCALIZATION NOTE (category.*):
+# These strings are displayed in the categories graph of the Performance Tools,
+# as the legend for each block in every bar. These labels should be kept
+# AS SHORT AS POSSIBLE so they don't obstruct important parts of the graph.
+category.other=Gecko
+category.layout=Cynllun
+category.js=JIT
+category.gc=GC
+category.network=Rhwydwaith
+category.graphics=Graffigau
+category.dom=DOM
+category.idle=Segur
+category.tools=Offer
+
+# LOCALIZATION NOTE (table.bytes):
+# This string is displayed in the call tree after bytesize units.
+# %S represents the value in bytes.
+table.bytes=%S B
+
+# LOCALIZATION NOTE (table.ms2):
+# This string is displayed in the call tree after units of time in milliseconds.
+# %S represents the value in milliseconds.
+table.ms2=%S ms
+
+# LOCALIZATION NOTE (table.percentage3):
+# This string is displayed in the call tree after units representing percentages.
+# %S represents the value in percentage with two decimal points, localized.
+# there are two "%" after %S to escape and display "%"
+table.percentage3=%S%%
+
+# LOCALIZATION NOTE (table.root):
+# This string is displayed in the call tree for the root node.
+table.root=(gwraidd)
+
+# LOCALIZATION NOTE (table.idle):
+# This string is displayed in the call tree for the idle blocks.
+table.idle=(oedi)
+
+# LOCALIZATION NOTE (table.url.tooltiptext):
+# This string is displayed in the call tree as the tooltip text for the url
+# labels which, when clicked, jump to the debugger.
+table.url.tooltiptext=Darllen y ffynhonnell yn y Dadfygiwr
+
+# LOCALIZATION NOTE (table.view-optimizations.tooltiptext2):
+# This string is displayed in the icon displayed next to frames that
+# have optimization data
+table.view-optimizations.tooltiptext2=Mae'r ffrâm yn cynnwys data wedi ei optimeiddio ar gyfer JIT
+
+# LOCALIZATION NOTE (recordingsList.importDialogTitle):
+# This string is displayed as a title for importing a recoring from disk.
+recordingsList.importDialogTitle=Mewnforio recordiad…
+
+# LOCALIZATION NOTE (recordingsList.saveDialogTitle):
+# This string is displayed as a title for saving a recording to disk.
+recordingsList.saveDialogTitle=Cadw recordiad…
+
+# LOCALIZATION NOTE (recordingsList.saveDialogJSONFilter):
+# This string is displayed as a filter for saving a recording to disk.
+recordingsList.saveDialogJSONFilter=Ffeiliau JSON
+
+# LOCALIZATION NOTE (recordingsList.saveDialogAllFilter):
+# This string is displayed as a filter for saving a recording to disk.
+recordingsList.saveDialogAllFilter=Pob Ffeil
+
+# LOCALIZATION NOTE (timeline.tick):
+# This string is displayed in the timeline overview, for delimiting ticks
+# by time, in milliseconds.
+timeline.tick=%S ms
+
+# LOCALIZATION NOTE (timeline.records):
+# This string is displayed in the timeline waterfall, as a title for the menu.
+timeline.records=COFNODION
+
+# LOCALIZATION NOTE (profiler.bufferFull):
+# This string is displayed when recording, indicating how much of the
+# buffer is currently be used.
+# %S is the percentage of the buffer used -- there are two "%"s after to escape
+# the % that is actually displayed.
+# Example: "Buffer 54% full"
+profiler.bufferFull=Byffer %S%% yn llawn
+
+# LOCALIZATION NOTE (recordings.start):
+# The label shown on the main recording buttons to start recording.
+recordings.start=Cychwyn Recordio Perfformiad
+
+# LOCALIZATION NOTE (recordings.stop):
+# The label shown on the main recording buttons to stop recording.
+recordings.stop=Atal Recordio Perfformiad
+
+# LOCALIZATION NOTE (recordings.start.tooltip):
+# This string is displayed as a tooltip on a button that starts a new profile.
+recordings.start.tooltip=Toglo cyflwr recordio o berfformiad recordio.
+
+# LOCALIZATION NOTE (recordings.import.tooltip):
+# This string is displayed on a button that opens a dialog to import a saved profile data file.
+recordings.import.tooltip=Mewnforio…
+
+# LOCALIZATION NOTE (recordings.clear.tooltip):
+# This string is displayed on a button that removes all the recordings.
+recordings.clear.tooltip=Clirio
diff --git a/l10n-cy/devtools/client/perftools.ftl b/l10n-cy/devtools/client/perftools.ftl
new file mode 100644
index 0000000000..d59e369c38
--- /dev/null
+++ b/l10n-cy/devtools/client/perftools.ftl
@@ -0,0 +1,106 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used in DevTools’ performance-new panel, about:profiling, and
+### the remote profiling panel. There are additional profiler strings in the appmenu.ftl
+### file that are used for the profiler popup.
+
+perftools-intro-title = Gosodiadau'r Proffiliwr
+perftools-intro-description =
+    Mae'r cofnodion yn cychwyn profiler.firefox.com mewn tab newydd. Mae'r holl ddata yn cael ei storio
+    yn lleol, ond gallwch ddewis ei lwytho i'w rannu.
+
+## All of the headings for the various sections.
+
+perftools-heading-settings = Gosodiadau Llawn
+perftools-heading-buffer = Gosodiadau'r Byffer
+perftools-heading-features = Nodweddion
+perftools-heading-features-default = Nodweddion (Ymlaen yn rhagosodedig drwy argymhelliad)
+perftools-heading-features-disabled = Nodweddion wedi'u Hanalluogi
+perftools-heading-features-experimental = Arbrofol
+perftools-heading-threads = Trywyddion
+perftools-heading-local-build = Adeiladedd lleol
+
+##
+
+perftools-description-intro =
+    Mae'r cofnodion yn cychwyn <a>profiler.firefox.com</a> mewn tab newydd. Mae'r holl ddata yn cael ei storio
+    yn lleol, ond gallwch ddewis ei lwytho i'w rannu.
+perftools-description-local-build =
+    Os ydych chi'n proffilio adeiladedd rydych wedi’i lunio'ch hun, ar y 
+    peiriant hwn,
+    ychwanegwch objdir eich adeiladedd at y rhestr isod fel bod
+    modd ei ddefnyddio i chwilio am fanylion symbolau.
+
+## The controls for the interval at which the profiler samples the code.
+
+perftools-range-interval-label = Cyfnod samplu:
+perftools-range-interval-milliseconds = { NUMBER($interval, maxFractionalUnits: 2) } ms
+
+##
+
+# The size of the memory buffer used to store things in the profiler.
+perftools-range-entries-label = Maint byffer:
+perftools-custom-threads-label = Ychwanegwch drywydd cyfaddas yn ôl enw:
+perftools-devtools-interval-label = Cyfnod:
+perftools-devtools-threads-label = Trywyddion:
+perftools-devtools-settings-label = Gosodiadau
+
+## Various statuses that affect the current state of profiling, not typically displayed.
+
+perftools-status-private-browsing-notice =
+    Mae'r proffiliwr wedi'i analluogi pan fydd Pori Preifat wedi'i alluogi.
+    Caewch yr holl Windows Preifat i ail-alluogi'r proffiliwr
+perftools-status-recording-stopped-by-another-tool = Cafodd y cofnodi ei atal gan offeryn arall.
+perftools-status-restart-required = Rhaid ailgychwyn y porwr i alluogi'r nodwedd hon.
+
+## These are shown briefly when the user is waiting for the profiler to respond.
+
+perftools-request-to-stop-profiler = Atal y cofnodi
+perftools-request-to-get-profile-and-stop-profiler = Cipio proffil
+
+##
+
+perftools-button-start-recording = Cychwyn cofnodi
+perftools-button-capture-recording = Cipio'r cofnod
+perftools-button-cancel-recording = Diddymu'r cofnodi
+perftools-button-save-settings = Cadw gosodiadau a mynd nôl
+perftools-button-restart = Ailgychwyn
+perftools-button-add-directory = Ychwanegwch gyfeiriadur
+perftools-button-remove-directory = Tynnwch y dewis
+perftools-button-edit-settings = Golygu Gosodiadau...
+
+## These messages are descriptions of the threads that can be enabled for the profiler.
+
+perftools-thread-gecko-main =
+    .title = Y prif brosesau ar gyfer y broses riant a phrosesau cynnwys
+perftools-thread-compositor =
+    .title = Cyfansoddion gyda'i gilydd gwahanol elfennau wedi'u paentio ar y dudalen
+perftools-thread-dom-worker =
+    .title = Dolen gweithwyr gwe a gweithwyr gwasanaeth
+perftools-thread-renderer =
+    .title = Pan fydd WebRender wedi'i alluogi, mae'r trywydd sy'n gweithredu OpenGL yn galw
+perftools-thread-render-backend =
+    .title = Trywydd WebRender RenderBackend
+perftools-thread-paint-worker =
+    .title = Pan mae off-main-thread wedi'i alluogi, yr edefyn y mae paentio yn digwydd arno
+perftools-thread-style-thread =
+    .title = Mae cyfrifiant arddull yn cael ei rannu i drywyddion lluosog
+pref-thread-stream-trans =
+    .title = Cludiant llif rhwydwaith
+perftools-thread-socket-thread =
+    .title = Y trywydd lle mae cod rhwydweithio yn rhedeg unrhyw alwadau rhwystro socedi
+perftools-thread-img-decoder =
+    .title = Trywyddion datgodio delwedd
+perftools-thread-dns-resolver =
+    .title = Mae datrysiad DNS yn digwydd ar y trywydd hwn
+perftools-thread-js-helper =
+    .title = Gwaith cefndir injan JS fel crynhoadau oddi ar y prif drywydd
+
+##
+
+perftools-record-all-registered-threads = Osgoi'r dewisiadau uchod a chofnodi'r holl drywyddion cofrestredig
+perftools-tools-threads-input-label =
+    .title = Mae'r enwau trywyddion hyn yn rhestr sydd wedi'i gwahanu â choma sy'n cael ei ddefnyddio i alluogi proffilio trywydd yn y proffiliwr. Mae angen i'r enw fod yn cyfateb yn unig â'r enw trywydd i'w gynnwys. Mae'n sensitif i ofod gwyn.
diff --git a/l10n-cy/devtools/client/responsive.properties b/l10n-cy/devtools/client/responsive.properties
new file mode 100644
index 0000000000..8f711cd63b
--- /dev/null
+++ b/l10n-cy/devtools/client/responsive.properties
@@ -0,0 +1,173 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Responsive Design Mode,
+# available from the Web Developer sub-menu -> 'Responsive Design Mode'.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (responsive.editDeviceList2): Context menu item displayed in the
+# device selector.
+responsive.editDeviceList2=Golygu Rhestr…
+
+# LOCALIZATION NOTE (responsive.exit): Tooltip text of the exit button.
+responsive.exit=Cau'r Modd Cynllunio Ymatebol
+
+# LOCALIZATION NOTE (responsive.rotate): Tooltip text of the rotate button.
+responsive.rotate=Cylchdroi'r port golwg
+
+# LOCALIZATION NOTE (responsive.responsiveMode): Placeholder text for the
+# device selector.
+responsive.responsiveMode=Ymatebol
+
+# LOCALIZATION NOTE (responsive.enableTouch): Tooltip text for the touch
+# simulation button when it's disabled.
+responsive.enableTouch=Galluogi efelychiad cyffwrdd
+
+# LOCALIZATION NOTE (responsive.disableTouch): Tooltip text for the touch
+# simulation button when it's enabled.
+responsive.disableTouch=Analluogi efelychiad cyffwrdd
+
+# LOCALIZATION NOTE  (responsive.screenshot): Tooltip of the screenshot button.
+responsive.screenshot=Cymryd llun sgrin o'r porth gweld
+
+# LOCALIZATION NOTE (responsive.screenshotGeneratedFilename): The auto generated
+# filename.
+# The first argument (%1$S) is the date string in yyyy-mm-dd format and the
+# second argument (%2$S) is the time string in HH.MM.SS format.
+responsive.screenshotGeneratedFilename=Llun Sgrin %1$S yn %2$S
+
+# LOCALIZATION NOTE (responsive.remoteOnly): Message displayed in the tab's
+# notification box if a user tries to open Responsive Design Mode in a
+# non-remote tab.
+responsive.remoteOnly=Mae'r Modd Cynllun Ymatebol ar gael yn unig ar gyfer tabiau porwyr pell, megis rhai sy'n cael ei ddefnyddio ar gyfer cynnwys gwe yn Firefox amlbroses.
+
+# LOCALIZATION NOTE (responsive.changeDevicePixelRatio): Tooltip for the
+# device pixel ratio dropdown when is enabled.
+responsive.changeDevicePixelRatio=Newid cyfradd picsel dyfais o'r portholwg
+
+# LOCALIZATION NOTE (responsive.devicePixelRatio.auto): Tooltip for the device pixel ratio
+# dropdown when it is disabled because a device is selected.
+# The argument (%1$S) is the selected device (e.g. iPhone 6) that set
+# automatically the device pixel ratio value.
+responsive.devicePixelRatio.auto=Cyfradd picsel dyfais yn cael ei osod yn awtomatig gan %1$S
+
+# LOCALIZATION NOTE (responsive.customDeviceName): Default value in a form to
+# add a custom device based on an arbitrary size (no association to an existing
+# device).
+responsive.customDeviceName=Dyfais Gyfaddas
+
+# LOCALIZATION NOTE (responsive.customDeviceNameFromBase): Default value in a
+# form to add a custom device based on the properties of another.  %1$S is the
+# name of the device we're staring from, such as "Apple iPhone 6".
+responsive.customDeviceNameFromBase=%1$S (Cyfaddas)
+
+# LOCALIZATION NOTE (responsive.addDevice2): Button text that reveals a form to
+# be used for adding custom devices.
+responsive.addDevice2=Ychwanegu Dyfais Gyfaddas…
+
+# LOCALIZATION NOTE (responsive.deviceAdderName): Label of form field for the
+# name of a new device.
+responsive.deviceAdderName=Enw
+
+# LOCALIZATION NOTE (responsive.deviceAdderSize): Label of form field for the
+# size of a new device.
+responsive.deviceAdderSize=Maint
+
+# LOCALIZATION NOTE (responsive.deviceAdderPixelRatio2): Label of form field for
+# the device pixel ratio of a new device.
+responsive.deviceAdderPixelRatio2=Cymhareb Picsel Dyfais
+
+# LOCALIZATION NOTE (responsive.deviceAdderUserAgent2): Label of form field for
+# the user agent of a new device.
+responsive.deviceAdderUserAgent2=Llinyn Asiant Defnyddiwr
+
+# LOCALIZATION NOTE (responsive.deviceAdderTouch2): Label of form field for the
+# touch input support of a new device.
+responsive.deviceAdderTouch2=Sgrin Gyffwrdd
+
+# LOCALIZATION NOTE (responsive.deviceAdderSave): Button text that submits a
+# form to add a new device.
+responsive.deviceAdderSave=Cyffwrdd
+
+# LOCALIZATION NOTE (responsive.deviceAdderCancel): Button text that cancels a
+# form to add a new device.
+responsive.deviceAdderCancel=Diddymu
+
+# LOCALIZATION NOTE (responsive.deviceDetails): Tooltip that appears when
+# hovering on a device in the device modal.  %1$S is the width of the device.
+# %2$S is the height of the device.  %3$S is the device pixel ratio value of the
+# device.  %4$S is the user agent of the device.  %5$S is a boolean value
+# noting whether touch input is supported.
+responsive.deviceDetails=Maint: %1$S x %2$S\nDPR: %3$S\nUA: %4$S\nCyffwrdd: %5$S
+
+# LOCALIZATION NOTE (responsive.deviceDetails.browserAndOS): Used to display the browser
+# and the OS in a tooltip that appears when hovering on a device in the device modal.
+# %1$S: browser
+# %2$S: OS
+responsive.deviceDetails.browserAndOS=%1$S ar %2$S
+
+# LOCALIZATION NOTE (responsive.deviceDetails.size): Used to display the pixel
+# size in a tooltip that appears when hovering on a device in the device modal.
+# %1$S: width
+# %2$S: height
+responsive.deviceDetails.size=Maint: %1$S x %2$S
+
+# LOCALIZATION NOTE (responsive.deviceDetails.DPR): Used to display the DPR in a tooltip
+# that appears when hovering on a device in the device modal.
+# %1$S: device pixel ratio
+responsive.deviceDetails.DPR=DPR: %1$S
+
+# LOCALIZATION NOTE (responsive.deviceDetails.UA): Used to display the UA in a tooltip
+# that appears when hovering on a device in the device modal.
+# %1$S: user agent
+responsive.deviceDetails.UA=UA: %1$S
+
+# LOCALIZATION NOTE (responsive.deviceDetails.touch): Used to display a boolean value
+# which is whether the touch input is supported or not in a tooltip that appears when
+# hovering on a device in the device modal.
+# %1$S: touch
+responsive.deviceDetails.touch=Cyffwrdd: %1$S
+
+# LOCALIZATION NOTE (responsive.devicePixelRatioOption): UI option in a menu to configure
+# the device pixel ratio. %1$S is the devicePixelRatio value of the device.
+responsive.devicePixelRatioOption=DPR: %1$S
+
+# LOCALIZATION NOTE (responsive.reloadConditions.touchSimulation): Label on checkbox used
+# to select whether to reload when touch simulation is toggled.
+responsive.reloadConditions.touchSimulation=Ail-lwytho pan mae efelychiad cyffwrdd wedi ei doglo
+
+# LOCALIZATION NOTE (responsive.reloadConditions.userAgent): Label on checkbox used
+# to select whether to reload when user agent is changed.
+responsive.reloadConditions.userAgent=Ail-lwytho pan mae asiant defnyddiwr wedi ei newid
+
+# LOCALIZATION NOTE (responsive.reloadNotification.description2): Text in notification bar
+# shown on first open to clarify that some features need a reload to apply.
+responsive.reloadNotification.description2=Mae newidiadau i efelychiad dyfais angen ail-lwytho i weithio'n iawn. Mae ail-lwytho awtomatig wedi eu hanalluogi drwy ragosodiad i osgoi colli unrhyw newidiadau yn DevTools. Gallwch alluogi ail-lwytho drwy'r ddewislen Gosodiadau.
+
+# LOCALIZATION NOTE (responsive.leftAlignViewport): Label on checkbox used in the settings
+# menu.
+responsive.leftAlignViewport=Alinio Viweport i'r chwith
+
+# LOCALIZATION NOTE (responsive.customUserAgent): This is the placeholder for the user
+# agent input in the responsive design mode toolbar.
+responsive.customUserAgent=Asiant Defnyddiwr Cyfaddas
+
+responsive.showUserAgentInput=Dangos asiant defnyddiwr
+
+# LOCALIZATION NOTE (responsive.deviceSettings): The header text for the device settings
+# view.
+responsive.deviceSettings=Gosodiadau Dyfais
+
+# LOCALIZATION NOTE (responsive.deviceNameAlreadyInUse): This is the text shown when adding a new
+# device with an already existing device name.
+responsive.deviceNameAlreadyInUse=Mae'r enw dyfais hwn eisoes yn cael ei ddefnyddio
+
+# LOCALIZATION NOTE (responsive.deviceFormUpdate): Button text that updates a custom
+# device when the form is submitted.
+responsive.deviceFormUpdate=Diweddaru
diff --git a/l10n-cy/devtools/client/shared.properties b/l10n-cy/devtools/client/shared.properties
new file mode 100644
index 0000000000..ae1cf972fe
--- /dev/null
+++ b/l10n-cy/devtools/client/shared.properties
@@ -0,0 +1,26 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (dimensions): This is used to display the dimensions
+# of a node or image, like 100×200.
+dimensions=%S×%S
+
+# LOCALIZATION NOTE (boxModelSize.accessibleLabel): This is used to read the
+# dimensions of a node by a screen reader. This helps communicate
+# the visual information in a more explicit form. Example:
+# Size: Width 100, height 200.
+boxModelSize.accessibleLabel=Size: Width %1$S, height %2$S
+
+# LOCALIZATION NOTE (boxModelInfo.accessibleLabel): This is used to read the
+# dimensions and position of a node by a screen reader. This helps communicate
+# the visual information in a more explicit form. Example:
+# Dimensions: Width 100, height 200, position static.
+boxModelInfo.accessibleLabel=Dimensions: Width %1$S, height %2$S, position %3$S
+
+# LOCALIZATION NOTE (boxModelEditable.accessibleLabel): The string spoken by
+# screen readers for each button in the box model view that opens that property
+# for editing. %1$S is the property displayed in the tooltip when hovering.
+# %2$S is the value that is visually displayed.
+# Example: margin-left: 0.
+boxModelEditable.accessibleLabel=%1$S: %2$S
diff --git a/l10n-cy/devtools/client/sourceeditor.dtd b/l10n-cy/devtools/client/sourceeditor.dtd
new file mode 100644
index 0000000000..eda7d9777d
--- /dev/null
+++ b/l10n-cy/devtools/client/sourceeditor.dtd
@@ -0,0 +1,25 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE : FILE This file contains the Source Editor component
+  - strings. The source editor component is used within the Scratchpad and
+  - Style Editor tools. -->
+
+<!-- LOCALIZATION NOTE : FILE This file contains the Source Editor component
+  - strings. The source editor component is used within the Style Editor. -->
+
+<!-- LOCALIZATION NOTE : FILE Do not translate commandkeys -->
+
+<!-- LOCALIZATION NOTE : FILE The correct localization of this file might be to
+  - keep it in English, or another language commonly spoken among web developers.
+  - You want to make that choice consistent across the developer tools.
+  - A good criteria is the language in which you'd find the best
+  - documentation on web development on the web. -->
+
+
+
+
+<!ENTITY gotoLineCmd.label         "Neidio i linell…">
+<!ENTITY gotoLineCmd.key           "J">
+<!ENTITY gotoLineCmd.accesskey     "N">
diff --git a/l10n-cy/devtools/client/sourceeditor.properties b/l10n-cy/devtools/client/sourceeditor.properties
new file mode 100644
index 0000000000..955a2655ec
--- /dev/null
+++ b/l10n-cy/devtools/client/sourceeditor.properties
@@ -0,0 +1,117 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Source Editor component.
+# This component is used whenever source code is displayed for the purpose of
+# being edited, inside the Firefox developer tools - current examples are the
+# Scratchpad and the Style Editor tools.
+
+# LOCALIZATION NOTE These strings are used inside the Source Editor component.
+# This component is used whenever source code is displayed for the purpose of
+# being edited, inside the Firefox developer tools (like Style Editor).
+
+# LOCALIZATION NOTE The correct localization of this file might be to keep it
+# in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best documentation
+# on web development on the web.
+
+# LOCALIZATION NOTE  (findCmd.promptMessage): This is the message shown when
+# the user wants to search for a string in the code. You can
+# access this feature by pressing Ctrl-F on Windows/Linux or Cmd-F on Mac.
+findCmd.promptMessage=Chwilio am:
+
+# LOCALIZATION NOTE  (gotoLineCmd.promptTitle): This is the dialog title used
+# when the user wants to jump to a specific line number in the code. You can
+# access this feature by pressing Ctrl-J on Windows/Linux or Cmd-J on Mac.
+gotoLineCmd.promptTitle=Mynd i linell…
+
+# LOCALIZATION NOTE  (autocompletion.docsLink): This is the text shown on
+# the link inside of the documentation popup.  If you type 'document' in Scratchpad
+# then press Shift+Space you can see the popup.
+autocompletion.docsLink=docs
+
+# LOCALIZATION NOTE  (autocompletion.notFound): This is the text shown in
+# the documentation popup if Tern fails to find a type for the object.
+autocompletion.notFound=heb ei ganfod
+
+# LOCALIZATION NOTE  (jumpToLine.commandkey): This is the key to use in
+# conjunction with accel (Command on Mac or Ctrl on other platforms) to jump to
+# a specific line in the editor.
+jumpToLine.commandkey=J
+
+# LOCALIZATION NOTE  (toggleComment.commandkey): This is the key to use in
+# conjunction with accel (Command on Mac or Ctrl on other platforms) to either
+# comment or uncomment selected lines in the editor.
+toggleComment.commandkey=/
+
+# LOCALIZATION NOTE  (indentLess.commandkey): This is the key to use in
+# conjunction with accel (Command on Mac or Ctrl on other platforms) to reduce
+# indentation level in CodeMirror. However, its default value also used by
+# the Toolbox to switch between tools so we disable it.
+#
+# DO NOT translate this key without proper synchronization with toolbox.dtd.
+indentLess.commandkey=[
+
+# LOCALIZATION NOTE  (indentMore.commandkey): This is the key to use in
+# conjunction with accel (Command on Mac or Ctrl on other platforms) to increase
+# indentation level in CodeMirror. However, its default value also used by
+# the Toolbox to switch between tools
+#
+# DO NOT translate this key without proper synchronization with toolbox.dtd.
+indentMore.commandkey=]
+
+# LOCALIZATION NOTE  (moveLineUp.commandkey): This is the combination of keys
+# used to move the current line up.
+# Do not localize "Alt", "Up", or change the format of the string. These are key
+# identifiers, not messages displayed to the user.
+moveLineUp.commandkey=Alt-Up
+
+# LOCALIZATION NOTE  (moveLineDown.commandkey): This is the combination of keys
+# used to move the current line up.
+# Do not localize "Alt", "Down", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+moveLineDown.commandkey=Alt-Down
+
+# LOCALIZATION NOTE  (autocompletion.commandkey): This is the key, used with
+# Ctrl, for code autocompletion.
+# Do not localize "Space", it's the key identifier, not a message displayed to
+# the user.
+autocompletion.commandkey=Space
+
+# LOCALIZATION NOTE  (showInformation2.commandkey): This is the combination of
+# keys used to display more information, like type inference.
+# Do not localize "Shift", "Ctrl", "Space", or change the format of the string.
+# These are key identifiers, not messages displayed to the user.
+showInformation2.commandkey=Shift-Ctrl-Space
+
+# LOCALIZATION NOTE  (find.key):
+# Key shortcut used to find the typed search
+# Do not localize "CmdOrCtrl", "F", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+find.key=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (replaceAll.key):
+# Key shortcut used to replace the content of the editor
+# Do not localize "Shift", "CmdOrCtrl", "F", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+replaceAll.key=Shift+CmdOrCtrl+F
+
+# LOCALIZATION NOTE (replaceAllMac.key):
+# Key shortcut used to replace the content of the editor on Mac
+# Do not localize "Alt", "CmdOrCtrl", "F", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+replaceAllMac.key=Alt+CmdOrCtrl+F
+
+# LOCALIZATION NOTE  (findNext.key):
+# Key shortcut used to find again the typed search
+# Do not localize "CmdOrCtrl", "G", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+findNext.key=CmdOrCtrl+G
+
+# LOCALIZATION NOTE (findPrev.key):
+# Key shortcut used to find the previous typed search
+# Do not localize "Shift", "CmdOrCtrl", "G", or change the format of the string. These are
+# key identifiers, not messages displayed to the user.
+findPrev.key=Shift+CmdOrCtrl+G
diff --git a/l10n-cy/devtools/client/startup.properties b/l10n-cy/devtools/client/startup.properties
new file mode 100644
index 0000000000..df29e4561f
--- /dev/null
+++ b/l10n-cy/devtools/client/startup.properties
@@ -0,0 +1,253 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (optionsButton.tooltip): This is used as the tooltip
+# for the options panel tab.
+optionsButton.tooltip=Dewisiadau Blwch Offer
+
+# LOCALIZATION NOTE (options.label): This is used as the label of the tab in
+# the devtools window.
+options.label=Dewisiadau
+
+# LOCALIZATION NOTE (options.panelLabel): This is used as the label for the
+# toolbox panel.
+options.panelLabel=Panel Dewisiadau Blwch Offer
+
+# LOCALIZATION NOTE (options.darkTheme.label2)
+# Used as a label for dark theme
+options.darkTheme.label2=Tywyll
+
+# LOCALIZATION NOTE (options.lightTheme.label2)
+# Used as a label for light theme
+options.lightTheme.label2=Golau
+
+# LOCALIZATION NOTE (performance.label):
+# This string is displayed in the title of the tab when the profiler is
+# displayed inside the developer tools window and in the Developer Tools Menu.
+performance.label=Perfformiad
+
+# LOCALIZATION NOTE (performance.panelLabel):
+# This is used as the label for the toolbox panel.
+performance.panelLabel=Panel Perfformiad
+
+# LOCALIZATION NOTE (performance.accesskey)
+# Used for the menuitem in the tool menu
+performance.accesskey=P
+
+# LOCALIZATION NOTE (performance.tooltip):
+# This string is displayed in the tooltip of the tab when the profiler is
+# displayed inside the developer tools window.
+# Keyboard shortcut for Performance Tools will be shown inside brackets.
+performance.tooltip=Perfformiad (%S)
+
+# LOCALIZATION NOTE (MenuWebconsole.label): the string displayed in the Tools
+# menu as a shortcut to open the devtools with the Web Console tab selected.
+MenuWebconsole.label=Consol Gwe
+
+# LOCALIZATION NOTE (ToolboxTabWebconsole.label): the string displayed as the
+# label of the tab in the devtools window.
+ToolboxTabWebconsole.label=Consol
+
+# LOCALIZATION NOTE (ToolboxWebConsole.panelLabel): the string used as the
+# label for the toolbox panel.
+ToolboxWebConsole.panelLabel=Panel y Consol
+
+# LOCALIZATION NOTE (ToolboxWebconsole.tooltip2): the string displayed in the
+# tooltip of the tab when the Web Console is displayed inside the developer
+# tools window.
+# Keyboard shortcut for Console will be shown inside the brackets.
+ToolboxWebconsole.tooltip2=Consol Gwe (%S)
+
+webConsoleCmd.accesskey=G
+
+# LOCALIZATION NOTE (ToolboxDebugger.label):
+# This string is displayed in the title of the tab when the debugger is
+# displayed inside the developer tools window and in the Developer Tools Menu.
+ToolboxDebugger.label=Dadfygiwr
+
+# LOCALIZATION NOTE (ToolboxDebugger.panelLabel):
+# This is used as the label for the toolbox panel.
+ToolboxDebugger.panelLabel=Panel Dadfygio
+
+# LOCALIZATION NOTE (ToolboxDebugger.tooltip4):
+# This string is displayed in the tooltip of the tab when the debugger is
+# displayed inside the developer tools window.
+ToolboxDebugger.tooltip4=Dadfygiwr JavaScript (%S)
+
+# LOCALIZATION NOTE (debuggerMenu.accesskey)
+# Used for the menuitem in the tool menu
+debuggerMenu.accesskey=D
+
+# LOCALIZATION NOTE (ToolboxStyleEditor.label):
+# This string is displayed in the title of the tab when the style editor is
+# displayed inside the developer tools window and in the Developer Tools Menu.
+ToolboxStyleEditor.label=Golygydd Arddull
+
+# LOCALIZATION NOTE (ToolboxStyleEditor.panelLabel):
+# This is used as the label for the toolbox panel.
+ToolboxStyleEditor.panelLabel=Panel Golygydd Arddull
+
+# LOCALIZATION NOTE (ToolboxStyleEditor.tooltip3):
+# This string is displayed in the tooltip of the tab when the style editor is
+# displayed inside the developer tools window.
+# A keyboard shortcut for Stylesheet Editor will be shown inside the latter pair of brackets.
+ToolboxStyleEditor.tooltip3=Golygydd Dalenni Steil (CSS) (%S)
+
+# LOCALIZATION NOTE (open.accesskey): The access key used to open the style
+# editor.
+open.accesskey=S
+
+# LOCALIZATION NOTE (inspector.*)
+# Used for the menuitem in the tool menu
+inspector.label=Archwiliwr
+inspector.accesskey=A
+
+# LOCALIZATION NOTE (inspector.panelLabel)
+# Labels applied to the panel and views within the panel in the toolbox
+inspector.panelLabel=Panel Archwilio
+
+# LOCALIZATION NOTE (inspector.tooltip2)
+# Keyboard shortcut for DOM and Style Inspector will be shown inside brackets.
+inspector.tooltip2=Arsylwr DOM ac Arddull (%S)
+
+# LOCALIZATION NOTE (inspector.mac.tooltip)
+# This is the exact same string as inspector.tooltip2, except that we show it
+# on mac only, where we support toggling the inspector with either cmd+shift+C,
+# or cmd+opt+C
+inspector.mac.tooltip=DOM a'r Archwilydd Arddull (%1$S neu %2$S)
+
+# LOCALIZATION NOTE (netmonitor.label):
+# This string is displayed in the title of the tab when the Network Monitor is
+# displayed inside the developer tools window and in the Developer Tools Menu.
+netmonitor.label=Rhwydwaith
+
+# LOCALIZATION NOTE (netmonitor.panelLabel):
+# This is used as the label for the toolbox panel.
+netmonitor.panelLabel=Panel Rhwydwaith
+
+# LOCALIZATION NOTE (netmonitor.accesskey)
+# Used for the menuitem in the tool menu
+netmonitor.accesskey=R
+
+# LOCALIZATION NOTE (netmonitor.tooltip2):
+# This string is displayed in the tooltip of the tab when the Network Monitor is
+# displayed inside the developer tools window.
+# Keyboard shortcut for Network Monitor will be shown inside the brackets.
+netmonitor.tooltip2=Monitor Rhwydwaith (%S)
+
+# LOCALIZATION NOTE (storage.accesskey): The access key used to open the storage
+# editor.
+storage.accesskey=S
+
+# LOCALIZATION NOTE (storage.label):
+# This string is displayed as the label of the tab in the developer tools window
+storage.label=Storfa
+
+# LOCALIZATION NOTE (storage.menuLabel):
+# This string is displayed in the Tools menu as a shortcut to open the devtools
+# with the Storage Inspector tab selected.
+storage.menuLabel=Archwiliwr Storio
+
+# LOCALIZATION NOTE (storage.panelLabel):
+# This string is used as the aria-label for the iframe of the Storage Inspector
+# tool in developer tools toolbox.
+storage.panelLabel=Panel Storio
+
+# LOCALIZATION NOTE (storage.tooltip3):
+# This string is displayed in the tooltip of the tab when the storage editor is
+# displayed inside the developer tools window.
+# A keyboard shortcut for Storage Inspector will be shown inside the brackets.
+storage.tooltip3=Archwiliwr Storio (Cwcis, Storio Lleol …) (%S)
+
+# LOCALIZATION NOTE (memory.label): This string is displayed in the title of the
+# tab when the memory tool is displayed inside the developer tools window and in
+# the Developer Tools Menu.
+memory.label=Cof
+
+# LOCALIZATION NOTE (memory.panelLabel): This is used as the label for the
+# toolbox panel.
+memory.panelLabel=Panel Cof
+
+# LOCALIZATION NOTE (memory.tooltip): This string is displayed in the tooltip of
+# the tab when the memory tool is displayed inside the developer tools window.
+memory.tooltip=Cof
+
+# LOCALIZATION NOTE (dom.label):
+# This string is displayed in the title of the tab when the DOM panel is
+# displayed inside the developer tools window and in the Developer Tools Menu.
+dom.label=DOM
+
+# LOCALIZATION NOTE (dom.panelLabel):
+# This is used as the label for the toolbox panel.
+dom.panelLabel=Panel DOM
+
+# LOCALIZATION NOTE (dom.accesskey)
+# Used for the menuitem in the tool menu
+dom.accesskey=D
+
+# LOCALIZATION NOTE (dom.tooltip):
+# This string is displayed in the tooltip of the tab when the DOM is
+# displayed inside the developer tools window.
+# Keyboard shortcut for DOM panel will be shown inside the brackets.
+dom.tooltip=DOM (%S)
+
+# LOCALIZATION NOTE (accessibility.label):
+# This string is displayed in the title of the tab when the Accessibility panel
+# is displayed inside the developer tools window and in the Developer Tools Menu.
+accessibility.label=Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.panelLabel):
+# This is used as the label for the toolbox panel.
+accessibility.panelLabel=Panel Hygyrchedd
+
+# LOCALIZATION NOTE (accessibility.accesskey)
+# Used for the menuitem in the tool menu
+accessibility.accesskey=y
+
+# LOCALIZATION NOTE (accessibility.tooltip3):
+# This string is displayed in the tooltip of the tab when the Accessibility is
+# displayed inside the developer tools window.
+# Keyboard shortcut for Accessibility panel will be shown inside the brackets.
+accessibility.tooltip3=Hygyrchedd (%S)
+
+# LOCALIZATION NOTE (application.label):
+# This string is displayed in the title of the tab when the Application panel
+# is displayed inside the developer tools window and in the Developer Tools Menu.
+application.label=Rhaglen
+
+# LOCALIZATION NOTE (application.panelLabel):
+# This is used as the label for the toolbox panel.
+application.panelLabel=Panel Rhaglenni
+
+# LOCALIZATION NOTE (application.tooltip):
+# This string is displayed in the tooltip of the tab when the Application panel is
+# displayed inside the developer tools window.
+application.tooltip=Panel Rhaglenni
+
+# LOCALIZATION NOTE (toolbox.buttons.responsive):
+# This is the tooltip of the button in the toolbox toolbar that toggles
+# the Responsive mode.
+# Keyboard shortcut will be shown inside brackets.
+toolbox.buttons.responsive = Modd Cynllunio Ymatebol (%S)
+
+# LOCALIZATION NOTE (toolbox.buttons.paintflashing):
+# This is the tooltip of the paintflashing button in the toolbox toolbar
+# that toggles paintflashing.
+toolbox.buttons.paintflashing = Toglo fflachio paent
+
+# LOCALIZATION NOTE (toolbox.buttons.screenshot):
+# This is the tooltip of the button in the toolbox toolbar that allows you to
+# take a screenshot of the entire page
+toolbox.buttons.screenshot = Cymrwch llun sgrin o'r dudalen gyfan
+
+# LOCALIZATION NOTE (toolbox.buttons.rulers):
+# This is the tooltip of the button in the toolbox toolbar that toggles the
+# rulers in the page
+toolbox.buttons.rulers = Toglo mesurydd y dudalen
+
+# LOCALIZATION NOTE (toolbox.buttons.measure):
+# This is the tooltip of the button in the toolbox toolbar that toggles the
+# measuring tools
+toolbox.buttons.measure = Mesur cyfran o'r dudalen
+
diff --git a/l10n-cy/devtools/client/storage.dtd b/l10n-cy/devtools/client/storage.dtd
new file mode 100644
index 0000000000..685a264f05
--- /dev/null
+++ b/l10n-cy/devtools/client/storage.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE : This file contains the Storage Inspector strings. -->
+
+<!-- LOCALIZATION NOTE : Placeholder for the searchbox that allows you to filter the table items. -->
+<!ENTITY searchBox.placeholder         "Hidlo eitemau">
+
+<!-- LOCALIZATION NOTE : Label of popup menu action to delete all storage items. -->
+<!ENTITY storage.popupMenu.deleteAllLabel "Dileu'r Cyfan">
+
+<!-- LOCALIZATION NOTE : Label of popup menu action to delete all session cookies. -->
+<!ENTITY storage.popupMenu.deleteAllSessionCookiesLabel "Dileu Pob Cwci Sesiwn">
+
+<!-- LOCALIZATION NOTE : Label of popup menu action to copy a storage item. -->
+<!ENTITY storage.popupMenu.copyLabel "Copïo">
diff --git a/l10n-cy/devtools/client/storage.ftl b/l10n-cy/devtools/client/storage.ftl
new file mode 100644
index 0000000000..032e5230d3
--- /dev/null
+++ b/l10n-cy/devtools/client/storage.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### These strings are used inside the Storage Inspector.
+
+# Hint shown when the selected storage host does not contain any data
+storage-table-empty-text = Dim data'n bresennol ar gyfer y gwesteiwr hwn
+
+# Hint shown when the cookies storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/Cookies
+storage-table-type-cookies-hint = Gweld a golygu cwcis trwy ddewis gwesteiwr. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
+
+# Hint shown when the local storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/Local_Storage_Session_Storage
+storage-table-type-localstorage-hint = Gweld a golygu'r storio lleol trwy ddewis gwesteiwr. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
+
+# Hint shown when the session storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/Local_Storage_Session_Storage
+storage-table-type-sessionstorage-hint = Gweld a golygu storio'r sesiwn trwy ddewis gwesteiwr. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
+
+# Hint shown when the IndexedDB storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/IndexedDB
+storage-table-type-indexeddb-hint = Gweld a dileu cofnodion IndexedDB trwy ddewis cronfa ddata. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
+
+# Hint shown when the cache storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/Cache_Storage
+storage-table-type-cache-hint = Gweld a dileu'r cofnodion storio storfa trwy ddewis storfa. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
+
+# Hint shown when the extension storage type is selected. Clicking the link will open
+# https://developer.mozilla.org/docs/Tools/Storage_Inspector/Extension_Storage
+storage-table-type-extensionstorage-hint = Gweld a golygu storfa'r estyniad trwy ddewis gwesteiwr. <a data-l10n-name="learn-more-link">Dysgu mwy</a>
diff --git a/l10n-cy/devtools/client/storage.properties b/l10n-cy/devtools/client/storage.properties
new file mode 100644
index 0000000000..458cae0bdd
--- /dev/null
+++ b/l10n-cy/devtools/client/storage.properties
@@ -0,0 +1,104 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Storage Editor tool.
+# LOCALIZATION NOTE The correct localization of this file might be to keep it
+# in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best documentation
+# on web development on the web.
+
+# LOCALIZATION NOTE (storage.filter.key):
+# Key shortcut used to focus the filter box on top of the data view
+storage.filter.key=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (tree.labels.*):
+# These strings are the labels for Storage type groups present in the Storage
+# Tree, like cookies, local storage etc.
+tree.labels.cookies=Cwcis
+tree.labels.localStorage=Storfa Leol
+tree.labels.sessionStorage=Storfa Sesiwn
+tree.labels.indexedDB=Cronfa Ddata wedi ei Fynegeio
+tree.labels.Cache=Storfa'r Storio Dros Dro
+
+tree.labels.extensionStorage=Storio Estyniad
+
+# LOCALIZATION NOTE (table.headers.*.*):
+# These strings are the header names of the columns in the Storage Table for
+# each type of storage available through the Storage Tree to the side.
+table.headers.cookies.name=Enw
+table.headers.cookies.value=Gwerth
+
+table.headers.cookies.expires2=Daw i ben / Oed-Uchaf
+table.headers.cookies.size=Maint
+table.headers.cookies.lastAccessed2=Mynediad Diwethaf
+table.headers.cookies.creationTime2=Crëwyd
+
+table.headers.Cache.status=Statws
+
+table.headers.indexedDB.uniqueKey=Allwedd unigryw
+table.headers.indexedDB.name=Allwedd
+table.headers.indexedDB.db=Enw Cronfa Ddata
+table.headers.indexedDB.storage=Storfa
+table.headers.indexedDB.objectStore=Enw Gwrthrych Storio
+table.headers.indexedDB.value=Gwerth
+table.headers.indexedDB.origin=Tarddiad
+table.headers.indexedDB.version=Fersiwn
+table.headers.indexedDB.objectStores=Storfa Gwrthrych
+table.headers.indexedDB.keyPath2=Llwybr Allwedd
+table.headers.indexedDB.autoIncrement=Awto-gynyddiad
+table.headers.indexedDB.indexes=Mynegeion
+
+table.headers.extensionStorage.area=Ardal Storio
+
+# LOCALIZATION NOTE (label.expires.session):
+# This string is displayed in the expires column when the cookie is Session
+# Cookie
+label.expires.session=Sesiwn
+
+# LOCALIZATION NOTE (storage.search.placeholder):
+# This is the placeholder text in the sidebar search box
+storage.search.placeholder=Gwerthoedd hidl
+
+# LOCALIZATION NOTE (storage.data.label):
+# This is the heading displayed over the item value in the sidebar
+storage.data.label=Data
+
+# LOCALIZATION NOTE (storage.parsedValue.label):
+# This is the heading displayed over the item parsed value in the sidebar
+storage.parsedValue.label=Gwerth Didoli
+
+# LOCALIZATION NOTE (storage.popupMenu.deleteLabel):
+# Label of popup menu action to delete storage item.
+storage.popupMenu.deleteLabel=Dileu “%S”
+
+# LOCALIZATION NOTE (storage.popupMenu.addItemLabel):
+# Label of popup menu action to add an item.
+storage.popupMenu.addItemLabel=Ychwanegu Eitem
+
+# LOCALIZATION NOTE (storage.popupMenu.refreshItemLabel):
+# Label of popup menu action to refresh an item.
+storage.popupMenu.refreshItemLabel=Adnewyddu eitemau
+
+# LOCALIZATION NOTE (storage.popupMenu.deleteAllFromLabel):
+# Label of popup menu action to delete all storage items.
+storage.popupMenu.deleteAllFromLabel=Dileu Popeth o “%S”
+
+# LOCALIZATION NOTE (storage.idb.deleteBlocked):
+# Warning notification when IndexedDB database could not be deleted immediately.
+storage.idb.deleteBlocked=Bydd y gronfa ddata “%S” yn cael ei ddileu ar ôl cau pob cysylltiadau.
+
+# LOCALIZATION NOTE (storage.idb.deleteError):
+# Error notification when IndexedDB database could not be deleted.
+storage.idb.deleteError=Nid oedd modd dileu cronfa ddata “%S”.
+
+# LOCALIZATION NOTE (storage.expandPane):
+# This is the tooltip for the button that collapses the right panel in the
+# storage UI when the panel is closed.
+storage.expandPane=Ehangu Paen
+
+# LOCALIZATION NOTE (storage.collapsePane):
+# This is the tooltip for the button that collapses the right panel in the
+# storage UI when the panel is open.
+storage.collapsePane=Cau Paen
diff --git a/l10n-cy/devtools/client/styleeditor.ftl b/l10n-cy/devtools/client/styleeditor.ftl
new file mode 100644
index 0000000000..1c42093716
--- /dev/null
+++ b/l10n-cy/devtools/client/styleeditor.ftl
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+styleeditor-new-button =
+    .tooltiptext = Creu ac atodi dalen arddull newydd i'r ddogfen
+    .accesskey = N
+styleeditor-import-button =
+    .tooltiptext = Mewnforio ac atodi dalen arddull cyfredol i'r ddogfen
+    .accesskey = M
+styleeditor-visibility-toggle =
+    .tooltiptext = Toglo gwelwdedd tudalen arddull
+    .accesskey = C
+styleeditor-save-button = Cadw
+    .tooltiptext = Cadw'r ddalen arddull i ffeil
+    .accesskey = C
+styleeditor-options-button =
+    .tooltiptext = Dewisiadau'r Golygydd Arddull
+styleeditor-media-rules = Rheolau @media
+styleeditor-editor-textbox =
+    .data-placeholder = Teipio'r CSS yma.
+styleeditor-no-stylesheet = Nid oes gan y dudalen ddalen arddull.
+styleeditor-no-stylesheet-tip = Efallai'r hoffech chi <a data-l10n-name="append-new-stylesheet">atodi dalen arddull newydd</a>?
+styleeditor-open-link-new-tab =
+    .label = Agor Dolen mewn Tab Newydd
+styleeditor-copy-url =
+    .label = Copïo'r URL
diff --git a/l10n-cy/devtools/client/styleeditor.properties b/l10n-cy/devtools/client/styleeditor.properties
new file mode 100644
index 0000000000..48eafaac7d
--- /dev/null
+++ b/l10n-cy/devtools/client/styleeditor.properties
@@ -0,0 +1,67 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Style Editor.
+# LOCALIZATION NOTE The correct localization of this file might be to keep it
+# in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best documentation
+# on web development on the web.
+
+# LOCALIZATION NOTE  (inlineStyleSheet): This is the name used for an style sheet
+# that is declared inline in the <style> element. Shown in the stylesheets list.
+# the argument is the index (order) of the containing <style> element in the
+# document.
+inlineStyleSheet=<inline style sheet #%S>
+
+# LOCALIZATION NOTE  (newStyleSheet): This is the default name for a new
+# user-created style sheet.
+newStyleSheet=Dalen arddull newydd #%S
+
+# LOCALIZATION NOTE  (ruleCount.label): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This is shown in the style sheets list.
+# #1 rule.
+# example: 111 rules.
+ruleCount.label=Dim rheolau.;#1 rheol.;#1 reol.;#1 rheol.;#1 rheol.;#1 rheol.
+
+# LOCALIZATION NOTE  (error-load): This is shown when loading fails.
+error-load=Methu llwytho'r ddalen arddull.
+
+# LOCALIZATION NOTE  (error-save): This is shown when saving fails.
+error-save=Methu cadw'r ddalen arddull.
+
+# LOCALIZATION NOTE  (importStyleSheet.title): This is the file picker title,
+# when you import a style sheet into the Style Editor.
+importStyleSheet.title=Mewnforio dalen arddull
+
+# LOCALIZATION NOTE  (importStyleSheet.filter): This is the *.css filter title
+importStyleSheet.filter=Ffeiliau CSS
+
+# LOCALIZATION NOTE  (saveStyleSheet.title): This is the file picker title,
+# when you save a style sheet from the Style Editor.
+saveStyleSheet.title=Cadw dalen arddull
+
+# LOCALIZATION NOTE  (saveStyleSheet.filter): This is the *.css filter title
+saveStyleSheet.filter=Ffeiliau CSS
+
+# LOCALIZATION NOTE  (saveStyleSheet.commandkey): This the key to use in
+# conjunction with accel (Command on Mac or Ctrl on other platforms) to Save
+saveStyleSheet.commandkey=S
+
+# LOCALIZATION NOTE  (showOriginalSources.label): This is the label on the context
+# menu item to toggle showing original sources in the editor.
+showOriginalSources.label=Dangos y ffynonellau gwreiddiol
+
+# LOCALIZATION NOTE  (showOriginalSources.accesskey): This is the access key for
+# the menu item to toggle showing original sources in the editor.
+showOriginalSources.accesskey=D
+
+# LOCALIZATION NOTE  (showMediaSidebar.label): This is the label on the context
+# menu item to toggle showing @media rule shortcuts in a sidebar.
+showMediaSidebar.label=Dangos bar ochr @media
+
+# LOCALIZATION NOTE  (showMediaSidebar.accesskey): This is the access key for
+# the menu item to toggle showing the @media sidebar.
+showMediaSidebar.accesskey=m
diff --git a/l10n-cy/devtools/client/toolbox-options.ftl b/l10n-cy/devtools/client/toolbox-options.ftl
new file mode 100644
index 0000000000..916f352c1d
--- /dev/null
+++ b/l10n-cy/devtools/client/toolbox-options.ftl
@@ -0,0 +1,139 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### Localization for Developer Tools options
+
+
+## Default Developer Tools section
+
+# The heading
+options-select-default-tools-label = Offer Datblygu Firefox Rhagosodedig
+
+# The label for the explanation of the * marker on a tool which is currently not supported
+# for the target of the toolbox.
+options-tool-not-supported-label = * Dim cefnogaeth ar gyfer targed y blwch offer cyfredol
+
+# The label for the heading of group of checkboxes corresponding to the developer tools
+# added by add-ons. This heading is hidden when there is no developer tool installed by add-ons.
+options-select-additional-tools-label = Offer Datblygu wedi eu gosod gan ychwanegion
+
+# The label for the heading of group of checkboxes corresponding to the default developer
+# tool buttons.
+options-select-enabled-toolbox-buttons-label = Botymau Blwch Offer sydd ar Gael
+
+# The label for the heading of the radiobox corresponding to the theme
+options-select-dev-tools-theme-label = Themâu
+
+## Inspector section
+
+# The heading
+options-context-inspector = Archwiliwr
+
+# The label for the checkbox option to show user agent styles
+options-show-user-agent-styles-label = Dangos Arddulliau Porwr
+options-show-user-agent-styles-tooltip =
+    .title = Bydd cychwyn hwn yn dangos yr arddulliau rhagosodedig sy'n cael eu llwytho gan y porwr.
+
+# The label for the checkbox option to enable collapse attributes
+options-collapse-attrs-label = Tocio priodoleddau DOM
+options-collapse-attrs-tooltip =
+    .title = Tocio'r priodoleddau hir yn yr arolygydd
+
+## "Default Color Unit" options for the Inspector
+
+options-default-color-unit-label = Uned lliw rhagnodedig
+options-default-color-unit-authored = Fel ei Awduro
+options-default-color-unit-hex = Hecs
+options-default-color-unit-hsl = HSL(A)
+options-default-color-unit-rgb = RGB(A)
+options-default-color-unit-name = Enw Lliwiau
+
+## Style Editor section
+
+# The heading
+options-styleeditor-label = Golygydd Arddull
+
+# The label for the checkbox that toggles autocompletion of css in the Style Editor
+options-stylesheet-autocompletion-label = Awtogwblhau CSS
+options-stylesheet-autocompletion-tooltip =
+    .title = Awtogwblhau priodweddau CSS, gwerthoedd a dewiswyr yn y Golygydd Steil wrth i chi deipio
+
+## Screenshot section
+
+# The heading
+options-screenshot-label = Ymddygiad Llun Sgrin
+
+# Label for the checkbox that toggles screenshot to clipboard feature
+options-screenshot-clipboard-label = Llun sgrin i'r clipfwrdd
+options-screenshot-clipboard-tooltip =
+    .title = Yn cadw i'r llun sgrin yn uniongyrchol i'r clipfwrdd
+
+# Label for the checkbox that toggles the camera shutter audio for screenshot tool
+options-screenshot-audio-label = Chwarae sain caead camera
+options-screenshot-audio-tooltip =
+    .title = Galluogi sain camera wrth gymryd llun sgrin
+
+## Editor section
+
+# The heading
+options-sourceeditor-label = Dewisiadau Golygu
+
+options-sourceeditor-detectindentation-tooltip =
+    .title = Dyfalu mewnoliad ar sail cynnwys y ffynhonnell
+options-sourceeditor-detectindentation-label = Canfod mewnoliad
+options-sourceeditor-autoclosebrackets-tooltip =
+    .title = Gosod bracedi cau yn awtomatig
+options-sourceeditor-autoclosebrackets-label = Cau bracedi'n awtomatig
+options-sourceeditor-expandtab-tooltip =
+    .title = Defnyddio bylchau yn lle nod tab
+options-sourceeditor-expandtab-label = Mewnoli gan ddefnyddio bylchau
+options-sourceeditor-tabsize-label = Maint tab
+options-sourceeditor-keybinding-label = Rhwymwyr allwedd
+options-sourceeditor-keybinding-default-label = Rhagosodiad
+
+## Advanced section
+
+# The heading
+options-context-advanced-settings = Gosodiadau uwch
+
+# The label for the checkbox that toggles the HTTP cache on or off
+options-disable-http-cache-label = Analluogi Storfa Dros Dro HTTP (pan mae'r blwch offer ar agor)
+options-disable-http-cache-tooltip =
+    .title = Bydd cychwyn y dewis hwn yn analluogi storfa dros dro'r HTTP ar gyfer pob tab sydd a' r blwch offer ar agor. Nid yw Service Workers yn cael eu heffeithio gan y dewis hwn.
+
+# The label for checkbox that toggles JavaScript on or off
+options-disable-javascript-label = Analluogi JavaScript *
+options-disable-javascript-tooltip =
+    .title = Bydd cychwyn y nodwedd hon yn analluogi JavaScript yn y tab cyfredol. Os fydd y tab neu’r blwch offer yn cael eu cau yna bydd y gosodiad hwn yn cael ei anghofio.
+
+# The label for checkbox that toggles chrome debugging, i.e. the devtools.chrome.enabled preference
+options-enable-chrome-label = Galluogi chrome y porwr ac ychwanegion blychau offer dadfygio
+options-enable-chrome-tooltip =
+    .title = Bydd cychwyn y dewis hwn yn caniatáu i chi ddefnyddio offer datblygwyr amrywiol o fewn cyd-destun porwr (drwy Offer > Datblygwr Gwe > Blwch Offer y Porwr) a dadfygio ychwanegion o'r Rheolwr Ychwanegion
+
+# The label for checkbox that toggles remote debugging, i.e. the devtools.debugger.remote-enabled preference
+options-enable-remote-label = Galluogi dadfygio pell
+
+options-enable-remote-tooltip2 =
+    .title = Bydd troi'r dewis hwn ymlaen yn caniatáu dadfygio enghraifft y porwr hwn o bell
+
+# The label for checkbox that toggles the service workers testing over HTTP on or off.
+options-enable-service-workers-http-label = Galluogi Service Workers dros HTTP (pan fydd y blwch offer ar agor)
+options-enable-service-workers-http-tooltip =
+    .title = Bydd cychwyn y dewis wn yn caniatáu i nodwedd service workers dros HTTP ar gyfer pob tab sydd â blwch offer ar agor.
+
+# The label for the checkbox that toggles source maps in all tools.
+options-source-maps-label = Galluogi Mapiau Ffynhonnell
+options-source-maps-tooltip =
+    .title = Os ydych yn galluogi'r dewis hwn bydd ffenylalanin cael eu mapio yn yr offer.
+
+# The message shown for settings that trigger page reload
+options-context-triggers-page-refresh = * Sesiwn gyfredol yn unig, ail-lwytho'r dudalen
+
+# The label for the checkbox that toggles the display of the platform data in the
+# Profiler i.e. devtools.profiler.ui.show-platform-data a boolean preference in about:config
+options-show-platform-data-label = Dangos data platfform Gecko
+options-show-platform-data-tooltip =
+    .title = Os ydych wedi galluogi'r dewis hwn bydd adroddiadau Proffiliwr JavaScript yn cynnwys symbolau platfform Gecko
diff --git a/l10n-cy/devtools/client/toolbox.properties b/l10n-cy/devtools/client/toolbox.properties
new file mode 100644
index 0000000000..e86405c021
--- /dev/null
+++ b/l10n-cy/devtools/client/toolbox.properties
@@ -0,0 +1,285 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (toolbox.titleTemplate1): This is the template
+# used to format the title of the toolbox.
+# The URL of the page being targeted: %1$S.
+toolbox.titleTemplate1=Offer Datblygu - %1$S
+
+# LOCALIZATION NOTE (toolbox.titleTemplate2): This is the template
+# used to format the title of the toolbox.
+# The page title or other name for the thing being targeted: %1$S
+# The URL of the page being targeted: %2$S.
+toolbox.titleTemplate2=Offer Datblygu - %1$S - %2$S
+
+# LOCALIZATION NOTE (toolbox.multiProcessBrowserToolboxTitle): Title used for
+# the Browser Toolbox when the pref `devtools.browsertoolbox.fission` is true.
+# This Browser Toolbox allows to debug the parent process as well as the content
+# processes in the same toolbox.
+toolbox.multiProcessBrowserToolboxTitle=Blwch Offer Amlbroses
+
+# LOCALIZATION NOTE (toolbox.defaultTitle): This is used as the tool
+# name when no tool is selected.
+toolbox.defaultTitle=Offer Datblygwyr
+
+# LOCALIZATION NOTE (toolbox.label): This is used as the label for the
+# toolbox as a whole
+toolbox.label=Offer Datblygwyr
+
+# LOCALIZATION NOTE (options.toolNotSupportedMarker): This is the template
+# used to add a * marker to the label for the Options Panel tool checkbox for the
+# tool which is not supported for the current toolbox target.
+# The name of the tool: %1$S.
+options.toolNotSupportedMarker=%1$S *
+
+# LOCALIZATION NOTE (toolbox.pickButton.tooltip)
+# This is the tooltip of the element picker button in the toolbox toolbar.
+# %S is the keyboard shortcut that toggles the element picker.
+toolbox.elementPicker.tooltip=Dewis elfen o'r dudalen (%S)
+
+# LOCALIZATION NOTE (toolbox.pickButton.mac.tooltip)
+# Like toolbox.pickButton.tooltip, but for macOS there are two possible keyboard
+# shortcuts: Cmd+Shift+C or Cmd+Opt+C
+toolbox.elementPicker.mac.tooltip=Dewis elfen o'r dudalen (%1$S neu %2$S)
+
+# LOCALIZATION NOTE (toolbox.elementPicker.key)
+# Key shortcut used to toggle the element picker.
+toolbox.elementPicker.key=CmdOrCtrl+Shift+C
+
+# LOCALIZATION NOTE (toolbox.elementPicker.mac.key)
+# Key shortcut used to toggle the element picker for macOS.
+toolbox.elementPicker.mac.key=Cmd+Opt+C
+
+# LOCALIZATION NOTE (toolbox.noContentProcessForTab.message)
+# Used as a message in the alert displayed when trying to open a browser
+# content toolbox and there is no content process running for the current tab
+toolbox.noContentProcessForTab.message=Dim cynnwys proses ar gyfer y tab.
+
+# LOCALIZATION NOTE (toolbox.viewCssSourceInStyleEditor.label)
+# Used as a message in either tooltips or contextual menu items to open the
+# corresponding URL as a css file in the Style-Editor tool.
+# DEV NOTE: Mostly used wherever toolbox.viewSourceInStyleEditorByXX is used.
+toolbox.viewCssSourceInStyleEditor.label=Agor Ffeil yn y Golygydd Arddull
+
+# LOCALIZATION NOTE (toolbox.viewJsSourceInDebugger.label)
+# Used as a message in either tooltips or contextual menu items to open the
+# corresponding URL as a js file in the Debugger tool.
+# DEV NOTE: Mostly used wherever toolbox.viewSourceInDebugger is used.
+toolbox.viewJsSourceInDebugger.label=Agor Ffeil yn y Dadfygiwr
+
+toolbox.resumeOrderWarning=Nid yw'r dudalen wedi ailgychwyn wedi i'r dadfygiwr gael ei atodi. I gywiro hyn, caewch ac ailagor y blwch offer.
+
+# LOCALIZATION NOTE (toolbox.help.key)
+# Key shortcut used to open the options panel
+toolbox.help.key=F1
+
+# LOCALIZATION NOTE (toolbox.nextTool.key)
+# Key shortcut used to select the next tool
+toolbox.nextTool.key=CmdOrCtrl+]
+
+# LOCALIZATION NOTE (toolbox.previousTool.key)
+# Key shortcut used to select the previous tool
+toolbox.previousTool.key=CmdOrCtrl+[
+
+# LOCALIZATION NOTE (toolbox.zoom*.key)
+# Key shortcuts used to zomm in/out or reset the toolbox
+# Should match fullZoom*Cmd.commandkey values from browser.dtd
+toolbox.zoomIn.key=CmdOrCtrl+Plus
+toolbox.zoomIn2.key=CmdOrCtrl+=
+
+toolbox.zoomOut.key=CmdOrCtrl+-
+toolbox.zoomOut2.key=
+
+toolbox.zoomReset.key=CmdOrCtrl+0
+toolbox.zoomReset2.key=
+
+# LOCALIZATION NOTE (toolbox.reload*.key)
+# Key shortcuts used to reload the page
+toolbox.reload.key=CmdOrCtrl+R
+toolbox.reload2.key=F5
+
+# LOCALIZATION NOTE (toolbox.forceReload*.key)
+# Key shortcuts used to force reload of the page by bypassing caches
+toolbox.forceReload.key=CmdOrCtrl+Shift+R
+toolbox.forceReload2.key=CmdOrCtrl+F5
+
+# LOCALIZATION NOTE (toolbox.toggleHost.key)
+# Key shortcut used to move the toolbox in bottom or side of the browser window
+toolbox.toggleHost.key=CmdOrCtrl+Shift+D
+
+# LOCALIZATION NOTE (toolbox.closeToolbox.key) Key shortcut used to close the toolbox
+toolbox.closeToolbox.key=CmdOrCtrl+W
+
+# LOCALIZATION NOTE (toolbox.toggleToolbox.key) Key shortcut used to toggle the toolbox
+toolbox.toggleToolbox.key=CmdOrCtrl+Shift+I
+
+# LOCALIZATION NOTE (toolbox.toggleToolboxOSX.key) Key shortcut used to toggle the toolbox
+toolbox.toggleToolboxOSX.key=CmdOrCtrl+Alt+I
+
+# LOCALIZATION NOTE (toolbox.toggleToolboxF12.key) Key shortcut used to toggle the toolbox
+toolbox.toggleToolboxF12.key=F12
+
+# LOCALIZATION NOTE (toolbox.frames.tooltip): This is the label for
+# the iframes menu list that appears only when the document has some.
+# It allows you to switch the context of the whole toolbox.
+toolbox.frames.tooltip=Dewiswch iframe fel y ddogfen targed cyfredol
+
+# LOCALIZATION NOTE (toolbox.frames.disabled.tooltip): This is the title
+# displayed as a tooltip of the iframes menu button, when disabled. The button
+# is normally hidden when no frames are available. But if the user is on the
+# DevTools Options panel, the button is always shown for discoverability.
+toolbox.frames.disabled.tooltip=Dim ond ar dudalennau gyda nifer o iframes mae'r botwm yma ar gael
+
+# LOCALIZATION NOTE (toolbox.showFrames.key)
+# Key shortcut used to show frames menu when 'frames' button is focused
+toolbox.showFrames.key=Alt+Down
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.button.tooltip): This is the tooltip
+# for the "..." button on the developer tools toolbox.
+toolbox.meatballMenu.button.tooltip=Cyfaddasu Offer Datblygwyr a chael cymorth
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.dock.*.label): These labels are shown
+# in the "..." menu in the toolbox and represent the different arrangements for
+# docking (or undocking) the developer tools toolbox.
+toolbox.meatballMenu.dock.bottom.label=Docio i'r gwaelod
+toolbox.meatballMenu.dock.left.label=Docio i'r chwith
+toolbox.meatballMenu.dock.right.label=Docio i'r dde
+toolbox.meatballMenu.dock.separateWindow.label=Ffenestr ar wahân
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.{splitconsole,hideconsole}.label):
+# These are the labels in the "..." menu in the toolbox for toggling the split
+# console window.
+# The keyboard shortcut will be shown to the side of the label.
+toolbox.meatballMenu.splitconsole.label=Dangos consol hollt
+toolbox.meatballMenu.hideconsole.label=Cuddio'r consol hollt
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.noautohide.label): This is the label
+# in the "..." menu in the toolbox to force the popups/panels to stay visible on
+# blur.
+# This is only visible in the browser toolbox as it is meant for
+# addon developers and Firefox contributors.
+toolbox.meatballMenu.noautohide.label=Analluogi awtoguddio llamlenni
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.settings.label): This is the label for
+# the item in the "..." menu in the toolbox that brings up the Settings
+# (Options) panel.
+# The keyboard shortcut will be shown to the side of the label.
+toolbox.meatballMenu.settings.label=Gosodiadau
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.documentation.label): This is the
+# label for the Documentation menu item.
+toolbox.meatballMenu.documentation.label=Dogfennaeth…
+
+# LOCALIZATION NOTE (toolbox.meatballMenu.community.label): This is the label
+# for the Community menu item.
+toolbox.meatballMenu.community.label=Cymuned…
+
+# LOCALIZATION NOTE (toolbox.closebutton.tooltip): This is the tooltip for
+# the close button the developer tools toolbox.
+toolbox.closebutton.tooltip=Cau'r Bar Offer Datblygwyr
+
+# LOCALIZATION NOTE (toolbox.errorCountButton.tooltip): This is the tooltip for
+# the error count button displayed in the developer tools toolbox.
+toolbox.errorCountButton.tooltip=Dangos Consol Hollt
+
+# LOCALIZATION NOTE (toolbox.errorCountButton.description): This is the description that
+# will be used for the error count button in the devTools settings panel.
+toolbox.errorCountButton.description=Dangos nifer y gwallau ar y dudalen
+
+# LOCALIZATION NOTE (toolbox.sourceMapFailure): This is shown in the web console
+# when there is a failure to fetch or parse a source map.
+# The text of the error: %1$S
+# The URL that caused DevTools to try to fetch a source map: %2$S
+# The URL of the source map itself: %3$S
+toolbox.sourceMapFailure=Gwall map ffynhonnell %1$S\nURL yr adnodd: %2$S\nURL map ddynhonnell: %3$S
+
+# LOCALIZATION NOTE (toolbox.sourceMapSourceFailure): This is shown in
+# the web console when there is a failure to fetch or parse an
+# original source that was mentioned in a source map.
+# The text of the error: %1$S
+# The URL of the source: %2$S
+toolbox.sourceMapSourceFailure=Gwall wrth estyn y ffynhonnell wreiddiol: %1$S\nURL ffynhonnell: %2$S
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.runtimeLabel): This is displayed as a toolbox
+# header in about:devtools-toolbox. about:devtools-toolbox is used for instance when
+# inspecting tabs in about:debugging.
+# e.g. Mozilla Fennec (65.0a1)
+# The name of runtime: %1$S
+# The version of runtime: %2$S
+toolbox.debugTargetInfo.runtimeLabel=%1$S (%2$S)
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.runtimeLabel.thisFirefox): this is displayed
+# as a toolbox header in about:devtools-toolbox, when inspecting the current Firefox runtime
+# (for instance, when inspecting one of its tabs in about:debugging)
+# e.g. This Firefox (65.0a1)
+# The version of runtime: %S
+toolbox.debugTargetInfo.runtimeLabel.thisFirefox=Y Firefox hwn (%S)
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.tabTitleRemote):
+# Used as the tab title for about:devtools-toolbox when connected to a remote target.
+# The connection type (see toolbox.debugTargetInfo.connection.*): %1$S
+# The target type (see toolbox.debugTargetInfo.targetType.*): %2$S
+# The target name (retrieved from DevTools, eg the extension's name): %3$S
+toolbox.debugTargetInfo.tabTitleRemote=Blwch offer (%1$S) - %2$S / %3$S
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.tabTitleLocal):
+# Used as the tab title for about:devtools-toolbox when connected to This Firefox.
+# The target type (see toolbox.debugTargetInfo.targetType.*): %1$S
+# The target name (retrieved from DevTools, eg the extension's name): %2$S
+toolbox.debugTargetInfo.tabTitleLocal=Blwch offer - %1$S / %2$S
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.tabTitleError):
+# Used as the tab title for about:devtools-toolbox when it failed to connect to the
+# target.
+toolbox.debugTargetInfo.tabTitleError=Blwch offer - digwyddodd gwall
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.connection.*): This is displayed in the
+# toolbox header in about:devtools-toolbox, to indicate how the connection to the
+# runtime being inspected was made.
+toolbox.debugTargetInfo.connection.usb=USB
+toolbox.debugTargetInfo.connection.network=Rhwydwaith
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.reload):
+# Used as the reload button tooltip
+toolbox.debugTargetInfo.reload=Ail-lwytho
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.forward):
+# Used as the navigation's "forward" button tooltip
+toolbox.debugTargetInfo.forward=Ymlaen
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.back):
+# Used as the navigation's "back" button tooltip
+toolbox.debugTargetInfo.back=Nôl
+
+# LOCALIZATION NOTE (toolbox.debugTargetInfo.targetType.*): This is displayed as the
+# alt attribute for an icon in the toolbox header in about:devtools-toolbox,
+# to indicate what is the type of the debug target being inspected.
+toolbox.debugTargetInfo.targetType.extension=Estyniad
+toolbox.debugTargetInfo.targetType.process=Proses
+toolbox.debugTargetInfo.targetType.tab=Tab
+toolbox.debugTargetInfo.targetType.worker=Gweithwyr
+
+# LOCALIZATION NOTE (browserToolbox.statusMessage): This is the label
+# shown next to status details when the Browser Toolbox fails to connect or
+# appears to be taking a while to do so.
+browserToolbox.statusMessage=Statws cysylltu Blwch Offer Porwr:
+
+# LOCALIZATION NOTE (toolbox.debugTargetErrorPage.title): This is the title
+# for the Error view shown by the toolbox when a connection to a debug target
+# could not be made
+toolbox.debugTargetErrorPage.title = Gwall
+
+# LOCALIZATION NOTE (toolbox.debugTargetErrorPage.description): This is the
+# text that appears in the Error view and explains to the user that an error
+# has happened while trying to connect to a debug target
+toolbox.debugTargetErrorPage.description = Methu cysylltu â'r targed dadfygio. Gweler y manylion gwall isod:
+
+# LOCALIZATION NOTE (options.deprecationNotice): This is the text that appears in the
+# settings panel for panel that will be removed in future releases.
+# This entire text is treated as a link to an MDN page.
+options.deprecationNotice=Anghydnaws. Dysgu Rhagor…
+
+# LOCALIZATION NOTE (options.enableMultiProcessToolbox): This is the text that appears in the
+# settings panel for the checkbox that enables the Multiprocess Browser Toolbox.
+options.enableMultiProcessToolbox=Galluogi'r Blwch Offer Porwr Amlbroses (mae angen ailgychwyn Blwch Offer y Porwr)
diff --git a/l10n-cy/devtools/client/tooltips.ftl b/l10n-cy/devtools/client/tooltips.ftl
new file mode 100644
index 0000000000..c0bdc72121
--- /dev/null
+++ b/l10n-cy/devtools/client/tooltips.ftl
@@ -0,0 +1,71 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### Localization for Developer Tools tooltips.
+
+learn-more = <span data-l10n-name ="link">Dysgu rhagor</span>
+
+## In the Rule View when a CSS property cannot be successfully applied we display
+## an icon. When this icon is hovered this message is displayed to explain why
+## the property is not applied.
+## Variables:
+##   $property (string) - A CSS property name e.g. "color".
+##   $display (string) - A CSS display value e.g. "inline-block".
+
+inactive-css-not-grid-or-flex-container = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n gynhwysydd flex nac yn gynhwysydd grid.
+inactive-css-not-grid-or-flex-container-or-multicol-container = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n gynhwysydd fflecs, yn gynhwysydd grid, neu'n gynhwysydd aml-golofn.
+inactive-css-not-grid-or-flex-item = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n grid nac yn eitem flex.
+inactive-css-not-grid-item = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n eitem grid.
+inactive-css-not-grid-container = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n gynhwysydd grid.
+inactive-css-not-flex-item = Nid yw <strong>{ $property }</strong> yn cael unrhyw effaith ar yr elfen hon gan nad yw'n eitem hyblyg.
+inactive-css-not-flex-container = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n gynhwysydd flex.
+inactive-css-not-inline-or-tablecell = Nid yw <strong> { $property } </strong> yn cael unrhyw effaith ar yr elfen hon gan nad yw'n elfen mewnlin neu gell tabl.
+inactive-css-property-because-of-display = Nid oes gan <strong>{ $property }</strong> unrhyw effaith ar yr elfen hon gan ei bod yn dangos  <strong>{ $display }</strong>.
+inactive-css-not-display-block-on-floated = Mae'r peiriant wedi newid y gwerth <strong>display</strong> i <strong>block</strong> oherwydd bod yr elfen yn <strong>arnofio</strong>.
+inactive-css-property-is-impossible-to-override-in-visited = Mae'n amhosib diystyru <strong>{ $property }</strong> oherwydd cyfyngiadau <strong>:visited</strong>.
+inactive-css-position-property-on-unpositioned-box = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n eitem wedi'i lleoli.
+inactive-text-overflow-when-no-overflow = Nid yw <strong>{ $property }</strong> yn cael unrhyw effaith ar yr elfen hon gan nad yw <strong>overflow:hidden</strong> wedi'i osod.
+inactive-outline-radius-when-outline-style-auto-or-none = Nid yw <strong>{ $property }</strong> yn cael unrhyw effaith ar yr elfen hon oherwydd bod ei <strong>arddull amlinellol</strong> yn <strong>awto</strong> neu'n <strong>ddim</strong>.
+inactive-css-not-for-internal-table-elements = Nid yw <strong>{ $property }</strong> yn cael unrhyw effaith ar elfennau tablau mewnol.
+inactive-css-not-for-internal-table-elements-except-table-cells = Nid yw <strong>{ $property }</strong> yn cael unrhyw effaith ar elfennau bwrdd mewnol ac eithrio celloedd bwrdd.
+inactive-css-not-table = Nid yw <strong>{ $property }</strong> yn effeithio ar yr elfen hon gan nad yw'n dabl.
+
+## In the Rule View when a CSS property cannot be successfully applied we display
+## an icon. When this icon is hovered this message is displayed to explain how
+## the problem can be solved.
+
+inactive-css-not-grid-or-flex-container-fix = Ceisiwch ychwanegu <strong>display:grid</strong> neu <strong>display:flex</strong>. { learn-more }
+inactive-css-not-grid-or-flex-container-or-multicol-container-fix = Ceisiwch ychwanegu naill ai <strong>display:grid</strong>, <strong>display:flex</strong>, neu <strong>columns:2</strong>. { learn-more }
+inactive-css-not-grid-or-flex-item-fix-2 = Ceisiwch ychwanegu <strong>display:grid</strong>, <strong>display:flex</strong>, <strong>display:inline-grid</strong> neu <strong>display:inline-flex</strong>. { learn-more }
+inactive-css-not-grid-item-fix-2 = Ceisiwch ychwanegu <strong>display:grid</strong> neu <strong>display:inline-grid</strong> at riant yr elfen. { learn-more }
+inactive-css-not-grid-container-fix = Ceisiwch ychwanegu <strong>display:grid</strong> neu <strong>display:inline-grid</strong>. { learn-more }
+inactive-css-not-flex-item-fix-2 = Ceisiwch ychwanegu <strong>display:flex</strong> neu <strong>display:inline-flex</strong> i riant yr elfen. { learn-more }
+inactive-css-not-flex-container-fix = Ceisiwch ychwanegu <strong>display:flex</strong> neu <strong>display:inline-flex</strong>. { learn-more }
+inactive-css-not-inline-or-tablecell-fix = Ceisiwch ychwanegu <strong>display:inline</strong> neu <strong>display:table-cell</strong>. { learn-more }
+inactive-css-non-replaced-inline-or-table-row-or-row-group-fix = Ceisiwch ychwanegu <strong>display:inline-block</strong> neu <strong>display:block</strong>. { learn-more }
+inactive-css-non-replaced-inline-or-table-column-or-column-group-fix = Ceisiwch ychwanegu <strong>display:inline-block</strong>. { learn-more }
+inactive-css-not-display-block-on-floated-fix = Ceisiwch dynnu <strong>float</strong> neu <strong>display:block</strong>. { learn-more }
+inactive-css-position-property-on-unpositioned-box-fix = Ceisiwch osod priodwedd ei <strong>leoliad</strong> i rywbeth arall heblaw <strong>statig</strong>. { learn-more }
+inactive-text-overflow-when-no-overflow-fix = Ceisiwch ychwanegu <strong>overflow:hidden</strong>. { learn-more }
+inactive-css-not-for-internal-table-elements-fix = Ceisiwch osod ei briodwedd <strong>arddangos</strong> i rywbeth arall heblaw <strong>cell-tabl</strong>, <strong>colofn-tabl</strong>, <strong>rhes-tabl</strong>, <strong>tabl-colofn-grŵp</strong>, <strong>tabl-rhes-grŵp</strong>, neu <strong>tabl-troedyn-grŵp</strong>. { learn-more }
+inactive-css-not-for-internal-table-elements-except-table-cells-fix = Ceisiwch osod ei briodwedd <strong>arddangos</strong> i rywbeth arall heblaw <strong>cell-tabl</strong>, <strong>colofn-tabl</strong>, <strong>rhes-tabl</strong>, <strong>tabl-colofn-grŵp</strong>, <strong>tabl-rhes-grŵp</strong>, neu <strong>tabl-troedyn-grŵp</strong>. { learn-more }
+inactive-outline-radius-when-outline-style-auto-or-none-fix = Ceisiwch osod ei briodwedd <strong>amlinellol</strong> i rywbeth heblaw'n <strong>awto</strong> neu'n <strong>ddim</strong>. { learn-more }
+inactive-css-not-table-fix = Ceisiwch ychwanegu <strong>display:table</strong> neu <strong>display:inline-table</strong>. { learn-more }
+
+## In the Rule View when a CSS property may have compatibility issues with other browsers
+## we display an icon. When this icon is hovered this message is displayed to explain why
+## the property is incompatible and the platforms it is incompatible on.
+## Variables:
+##   $property (string) - A CSS declaration name e.g. "-moz-user-select" that can be a platform specific alias.
+##   $rootProperty (string) - A raw CSS property name e.g. "user-select" that is not a platform specific alias.
+
+css-compatibility-default-message = Nid yw <strong>{ $property }</strong> yn cael ei gefnogi gan y porwyr canlynol:
+css-compatibility-deprecated-experimental-message = Roedd <strong>{ $property }</strong> yn briodoledd arbrofol sydd bellach yn cael ei anghymeradwyo gan safonau'r W3C. Nid yw'n cael ei gefnogi gan y porwyr canlynol:
+css-compatibility-deprecated-experimental-supported-message = Roedd <strong>{ $property }</strong> yn briodwedd arbrofol sydd bellach yn cael ei anghymeradwyo gan safonau'r W3C.
+css-compatibility-deprecated-message = Mae <strong>{ $property }</strong> yn cael ei anghymeradwyo gan safonau'r W3C. Nid yw'n cael ei gefnogi gan y porwyr canlynol:
+css-compatibility-deprecated-supported-message = Mae <strong>{ $property }</strong> yn cael ei anghymeradwyo gan safonau'r W3C.
+css-compatibility-experimental-message = Mae <strong>{ $property }</strong> yn briodwedd arbrofol. Nid yw'n cael ei gefnogi gan y porwyr canlynol:
+css-compatibility-experimental-supported-message = Mae <strong>{ $property }</strong> yn briodwedd arbrofol.
+css-compatibility-learn-more-message = <span data-l10n-name="link">Dysgu rhagor</span> am <strong>{ $rootProperty }</strong>
diff --git a/l10n-cy/devtools/client/webconsole.properties b/l10n-cy/devtools/client/webconsole.properties
new file mode 100644
index 0000000000..ee61556a3a
--- /dev/null
+++ b/l10n-cy/devtools/client/webconsole.properties
@@ -0,0 +1,561 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# LOCALIZATION NOTE
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (browserConsole.title): shown as the
+# title when opening the browser console popup
+browserConsole.title=Consol y Porwr
+
+# LOCALIZATION NOTE (multiProcessBrowserConsole.title): Title of the Browser
+# Console window when the pref `devtools.browsertoolbox.fission` is true. This
+# Browser Console will log messages from all processes, not just the the parent
+# process.
+multiProcessBrowserConsole.title=Consol Porwr Amlbroses
+
+# LOCALIZATION NOTE (timestampFormat): %1$02S = hours (24-hour clock),
+# %2$02S = minutes, %3$02S = seconds, %4$03S = milliseconds.
+timestampFormat=%02S:%02S:%02S.%03S
+
+ConsoleAPIDisabled=Mae'r API cofnodi Consol Gwe (console.log, console.info, console.warn, console.error) wedi ei analluogi gan sgript ar y dudalen.
+
+# LOCALIZATION NOTE (webConsoleXhrIndicator): the indicator displayed before
+# a URL in the Web Console that was requested using an XMLHttpRequest.
+webConsoleXhrIndicator=XHR
+
+# LOCALIZATION NOTE (webConsoleMoreInfoLabel): the more info tag displayed
+# after security related web console messages.
+webConsoleMoreInfoLabel=Dysgu Rhagor
+
+# LOCALIZATION NOTE (stacktrace.anonymousFunction): this string is used to
+# display JavaScript functions that have no given name - they are said to be
+# anonymous. Test console.trace() in the webconsole.
+stacktrace.anonymousFunction=<anhysbys>
+
+# LOCALIZATION NOTE (stacktrace.asyncStack): this string is used to
+# indicate that a given stack frame has an async parent.
+# %S is the "Async Cause" of the frame.
+stacktrace.asyncStack=(Async: %S)
+
+# LOCALIZATION NOTE (timeLog): this string is used to display the result of
+# the console.timeLog() call. Parameters: %1$S is the name of the timer, %2$S
+# is the number of milliseconds.
+timeLog=%1$S: %2$Sms
+
+# LOCALIZATION NOTE (console.timeEnd): this string is used to display the result of
+# the console.timeEnd() call. Parameters: %1$S is the name of the timer, %2$S
+# is the number of milliseconds.
+console.timeEnd=%1$S: %2$Sms - daeth yr amserydd i ben
+
+# LOCALIZATION NOTE (consoleCleared): this string is displayed when receiving a
+# call to console.clear() to let the user know the previous messages of the
+# console have been removed programmatically.
+consoleCleared=Cliriwyd y consol.
+
+# LOCALIZATION NOTE (noCounterLabel): this string is used to display
+# count-messages with no label provided.
+noCounterLabel=<no label>
+
+# LOCALIZATION NOTE (counterDoesntExist): this string is displayed when
+# console.countReset() is called with a counter that doesn't exist.
+counterDoesntExist=Nid yw amserydd “%S” yn bodoli.
+
+# LOCALIZATION NOTE (noGroupLabel): this string is used to display
+# console.group messages with no label provided.
+noGroupLabel=<no group label>
+
+maxTimersExceeded=Aethpwyd dros y nifer o amseryddion mae'r dudalen yn eu caniatáu.
+timerAlreadyExists=Mae amserydd “%S” yn bodoli eisoes.
+timerDoesntExist=Nid yw amserydd “%S” yn bodoli.
+timerJSError=Methu prosesu enw'r amserydd.
+
+# LOCALIZATION NOTE (connectionTimeout): message displayed when the Remote Web
+# Console fails to connect to the server due to a timeout.
+connectionTimeout=Terfynwyd amser y cysylltiad. Gwiriwch y Consol Gwall ar y ddau ben am negeseuon gwall posib. Ail agorwch y Consol Gwe i geisio eto.
+
+# LOCALIZATION NOTE (propertiesFilterPlaceholder): this is the text that
+# appears in the filter text box for the properties view container.
+propertiesFilterPlaceholder=Priodweddau hidlau
+
+# LOCALIZATION NOTE (messageRepeats.tooltip2): the tooltip text that is displayed
+# when you hover the red bubble that shows how many times a message is repeated
+# in the web console output.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of message repeats
+# example: 3 repeats
+messageRepeats.tooltip2=Dim ailadroddiadau;#1 ailadroddiad;#1 ailadroddiad;#1 ailadroddiad;#1 ailadroddiad;#1 ailadroddiad
+
+# LOCALIZATION NOTE (openNodeInInspector): the text that is displayed in a
+# tooltip when hovering over the inspector icon next to a DOM Node in the console
+# output
+openNodeInInspector=Cliciwch i ddewis nod yn yr archwiliwr
+
+# LOCALIZATION NOTE (cdFunctionInvalidArgument): the text that is displayed when
+# cd() is invoked with an invalid argument.
+cdFunctionInvalidArgument=Methu gwneud cd() i ffenestr. Ymresymiad annilys.
+
+# LOCALIZATION NOTE (selfxss.msg): the text that is displayed when
+# a new user of the developer tools pastes code into the console
+# %1 is the text of selfxss.okstring
+selfxss.msg=Rhybudd rhag Twyll: Cymrwch ofal wrth gludo pethau nad ydych yn eu deall. Gall hyn ganiatáu i ymosodwyr ddwyn eich hunaniaeth neu gymryd rheolaeth o'ch cyfrifiadur. Teipiwch '%S' isod (does dim angen pwyso Enter) i ganiatáu gludo.
+
+# LOCALIZATION NOTE (selfxss.okstring): the string to be typed
+# in by a new user of the developer tools when they receive the sefxss.msg prompt.
+# Please avoid using non-keyboard characters here
+selfxss.okstring=caniatáu gludo
+
+# LOCALIZATION NOTE (messageToggleDetails): the text that is displayed when
+# you hover the arrow for expanding/collapsing the message details. For
+# console.error() and other messages we show the stacktrace.
+messageToggleDetails=Dangos/cuddio manylion neges.
+
+# LOCALIZATION NOTE (groupToggle): the text that is displayed when
+# you hover the arrow for expanding/collapsing the messages of a group.
+groupToggle=Dangos cuddio grŵp.
+
+# LOCALIZATION NOTE (table.index, table.iterationIndex, table.key, table.value):
+# the column header displayed in the console table widget.
+table.index=(mynegai)
+table.iterationIndex=(mynegai iteriad)
+table.key=Allwedd
+table.value=Gwerthoedd
+
+# LOCALIZATION NOTE (level.error, level.warn, level.info, level.log, level.debug):
+# tooltip for icons next to console output
+level.error=Gwall
+level.warn=Rhybudd
+level.info=Gwybodaeth
+level.log=Cofnodi
+level.debug=Dadfygio
+
+# LOCALIZATION NOTE (logpoint.title)
+# Tooltip shown for logpoints sent from the debugger
+logpoint.title=Pwyntiau cofnodi o'r dadfygiwr
+
+# LOCALIZATION NOTE (blockedReason.title)
+# Tooltip shown for blocked network events sent from the network panel
+blockedrequest.label=Wedi'i rwystro gan DevTools
+
+# LOCALIZATION NOTE (webconsole.find.key)
+# Key shortcut used to focus the search box on upper right of the console
+webconsole.find.key=CmdOrCtrl+F
+
+# LOCALIZATION NOTE (webconsole.close.key)
+# Key shortcut used to close the Browser console (doesn't work in regular web console)
+webconsole.close.key=CmdOrCtrl+W
+
+# LOCALIZATION NOTE (webconsole.clear.key*)
+# Key shortcut used to clear the console output
+webconsole.clear.key=Ctrl+Shift+L
+webconsole.clear.keyOSX=Ctrl+L
+webconsole.clear.alternativeKeyOSX=Cmd+K
+
+# LOCALIZATION NOTE (webconsole.menu.copyURL.label)
+# Label used for a context-menu item displayed for network message logs. Clicking on it
+# copies the URL displayed in the message to the clipboard.
+webconsole.menu.copyURL.label=Copïo Lleoliad Dolen
+webconsole.menu.copyURL.accesskey=C
+
+# LOCALIZATION NOTE (webconsole.menu.openURL.label)
+# Label used for a context-menu item displayed for network message logs. Clicking on it
+# opens the URL displayed in a new browser tab.
+webconsole.menu.openURL.label=Agor URL mewn Tab Newydd
+webconsole.menu.openURL.accesskey=T
+
+# LOCALIZATION NOTE (webconsole.menu.openInNetworkPanel.label)
+# Label used for a context-menu item displayed for network message logs. Clicking on it
+# opens the network message in the Network panel
+webconsole.menu.openInNetworkPanel.label=Agor mewn Panel Rhwydwaith
+webconsole.menu.openInNetworkPanel.accesskey=P
+
+# LOCALIZATION NOTE (webconsole.menu.resendNetworkRequest.label)
+# Label used for a context-menu item displayed for network message logs. Clicking on it
+# resends the network request
+webconsole.menu.resendNetworkRequest.label=Ail anfon Cais
+webconsole.menu.resendNetworkRequest.accesskey=a
+
+# LOCALIZATION NOTE (webconsole.menu.openNodeInInspector.label)
+# Label used for a context-menu item displayed for DOM Node logs. Clicking on it will
+# reveal that specific DOM Node in the Inspector.
+webconsole.menu.openNodeInInspector.label=Datgelu yn yr Arolygydd
+webconsole.menu.openNodeInInspector.accesskey=Q
+
+# LOCALIZATION NOTE (webconsole.menu.storeAsGlobalVar.label)
+# Label used for a context-menu item displayed for object/variable logs. Clicking on it
+# creates a new global variable pointing to the logged variable.
+webconsole.menu.storeAsGlobalVar.label=Cadw fel amrywiolyn cyffredinol
+webconsole.menu.storeAsGlobalVar.accesskey=C
+
+# LOCALIZATION NOTE (webconsole.menu.copyMessage.label)
+# Label used for a context-menu item displayed for any log. Clicking on it will copy the
+# content of the log (or the user selection, if any).
+webconsole.menu.copyMessage.label=Copïo neges
+webconsole.menu.copyMessage.accesskey=C
+
+# LOCALIZATION NOTE (webconsole.menu.copyObject.label)
+# Label used for a context-menu item displayed for object/variable log. Clicking on it
+# will copy the object/variable.
+webconsole.menu.copyObject.label=Copïo gwrthrych
+webconsole.menu.copyObject.accesskey=g
+
+# LOCALIZATION NOTE (webconsole.menu.selectAll.label)
+# Label used for a context-menu item that will select all the content of the webconsole
+# output.
+webconsole.menu.selectAll.label=Dewis popeth
+webconsole.menu.selectAll.accesskey=p
+
+# LOCALIZATION NOTE (webconsole.menu.openInSidebar.label)
+# Label used for a context-menu item displayed for object/variable logs. Clicking on it
+# opens the webconsole sidebar for the logged variable.
+webconsole.menu.openInSidebar.label1=Archwiliwch y gwrthrych yn y Bar Ochr
+webconsole.menu.openInSidebar.accesskey=A
+
+# LOCALIZATION NOTE (webconsole.menu.exportSubmenu.label)
+# Label used for a context-menu item displayed on the output. Clicking on it
+# opens a submenu where the user can select how to export messages.
+webconsole.menu.exportSubmenu.label=Allforio negeseuon gweladwy i
+
+# LOCALIZATION NOTE (webconsole.menu.exportClipboard.label)
+# Label used for a context-menu item displayed on the output. Clicking on it
+# copies the entire output of the console to the clipboard.
+webconsole.menu.exportSubmenu.exportCliboard.label=Clipfwrdd
+
+# LOCALIZATION NOTE (webconsole.menu.exportFile.label)
+# Label used for a context-menu item displayed on the output. Clicking on it
+# opens a file picker to allow the user save a file containing
+# the output of the console.
+webconsole.menu.exportSubmenu.exportFile.label=Ffeil
+
+# LOCALIZATION NOTE (webconsole.clearButton.tooltip)
+# Label used for the tooltip on the clear logs button in the console top toolbar bar.
+# Clicking on it will clear the content of the console.
+webconsole.clearButton.tooltip=Clirio allbwn y Consol Gwe
+
+# LOCALIZATION NOTE (webconsole.toggleFilterButton.tooltip)
+# Label used for the tooltip on the toggle filter bar button in the console top
+# toolbar bar. Clicking on it will toggle the visibility of an additional bar which
+# contains filter buttons.
+webconsole.toggleFilterButton.tooltip=Toglo bar yr hidl
+
+# LOCALIZATION NOTE (webconsole.filterInput.placeholder)
+# Label used for for the placeholder on the filter input, in the console top toolbar.
+webconsole.filterInput.placeholder=Allbwn hidl
+
+# LOCALIZATION NOTE (webconsole.errorsFilterButton.label)
+# Label used as the text of the "Errors" button in the additional filter toolbar.
+# It shows or hides error messages, either inserted in the page using
+# console.error() or as a result of a javascript error..
+webconsole.errorsFilterButton.label=Gwallau
+
+# LOCALIZATION NOTE (webconsole.warningsFilterButton.label)
+# Label used as the text of the "Warnings" button in the additional filter toolbar.
+# It shows or hides warning messages, inserted in the page using console.warn().
+webconsole.warningsFilterButton.label=Rhybuddion
+
+# LOCALIZATION NOTE (webconsole.logsFilterButton.label)
+# Label used as the text of the "Logs" button in the additional filter toolbar.
+# It shows or hides log messages, inserted in the page using console.log().
+webconsole.logsFilterButton.label=Cofnodi
+
+# LOCALIZATION NOTE (webconsole.infoFilterButton.label)
+# Label used as the text of the "Info" button in the additional filter toolbar.
+# It shows or hides info messages, inserted in the page using console.info().
+webconsole.infoFilterButton.label=Gwybodaeth
+
+# LOCALIZATION NOTE (webconsole.debugFilterButton.label)
+# Label used as the text of the "Debug" button in the additional filter toolbar.
+# It shows or hides debug messages, inserted in the page using console.debug().
+webconsole.debugFilterButton.label=Dadfygio
+
+# LOCALIZATION NOTE (webconsole.cssFilterButton.label)
+# Label used as the text of the "CSS" button in the additional filter toolbar.
+# It shows or hides CSS warning messages, inserted in the page by the browser
+# when there are CSS errors in the page.
+webconsole.cssFilterButton.label=CSS
+
+# LOCALIZATION NOTE (webconsole.cssFilterButton.inactive.tooltip)
+# Label used as the tooltip of the "CSS" button in the additional filter toolbar, when the
+# filter is inactive (=unchecked).
+webconsole.cssFilterButton.inactive.tooltip=Bydd taflenni arddull yn cael eu hailddidoli i wirio am wallau. Adnewyddwch y dudalen hefyd i weld gwallau o daflenni arddull wedi'u haddasu o Javascript.
+
+# LOCALIZATION NOTE (webconsole.xhrFilterButton.label)
+# Label used as the text of the "XHR" button in the additional filter toolbar.
+# It shows or hides messages displayed when the page makes an XMLHttpRequest or
+# a fetch call.
+webconsole.xhrFilterButton.label=XHR
+
+# LOCALIZATION NOTE (webconsole.requestsFilterButton.label)
+# Label used as the text of the "Requests" button in the additional filter toolbar.
+# It shows or hides messages displayed when the page makes a network call, for example
+# when an image or a scripts is requested.
+webconsole.requestsFilterButton.label=Ceisiadau
+
+# LOCALIZATION NOTE (webconsole.filteredMessagesByText.label)
+# Text on the filter input displayed when some console messages are hidden because the
+# user has filled in the input.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# example: 345 hidden.
+webconsole.filteredMessagesByText.label=#1 cudd;#1 cudd;#1 cudd;#1 cudd;#1 cudd;
+
+# LOCALIZATION NOTE (webconsole.filteredMessagesByText.tooltip)
+# Tooltip on the filter input "hidden" text, displayed when some console messages are
+# hidden because the user has filled in the input.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# example: 345 items hidden by text filter.
+webconsole.filteredMessagesByText.tooltip=Dim eitemau wedi eu cuddio gan hidlyddion;#1 eitem wedi ei guddio gan hidlyddion;#1 eitem wedi eu cuddio gan hidlyddion;#1 eitem wedi eu cuddio gan hidlyddion;#1 eitem wedi eu cuddio gan hidlyddion;#1 eitem wedi eu cuddio gan hidlyddion
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.menuButton.tooltip)
+# Tooltip for the filter bar preferences menu. This menu will display multiple perefences for the
+# filter bar, such as enabling the compact toolbar mode, enable the timestamps, persist logs, etc
+webconsole.console.settings.menu.button.tooltip=Gosodiadau'r Consol
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.compactToolbar.label)
+# Label for the `Compact Toolbar` preference option. This will turn the message filters buttons
+# into a Menu Button, making the filter bar more compact.
+webconsole.console.settings.menu.item.compactToolbar.label=Bar Offer Cryno
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.timestamps.label)
+# Label for enabling the timestamps in the Web Console.
+webconsole.console.settings.menu.item.timestamps.label=Dangos Stampiau Amser
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.timestamps.tooltip)
+webconsole.console.settings.menu.item.timestamps.tooltip=Os ydych chi'n galluogi'r dewis hwn bydd gorchmynion ac allbwn yn y Consol Gwe yn dangos stamp amser
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.warningGroups.label)
+# Label for grouping the similar messages in the Web Console
+webconsole.console.settings.menu.item.warningGroups.label=Grwpio Negeseuon Tebyg
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.warningGroups.tooltip)
+webconsole.console.settings.menu.item.warningGroups.tooltip=Pan wedi eu galluogi, bydd negeseuon tebyg yn cael eu rhoi mewn grwpiau
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.autocomplete.label)
+# Label for enabling autocomplete for input in the Web Console
+webconsole.console.settings.menu.item.autocomplete.label=Galluogi awtogwblhau
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.autocomplete.tooltip)
+webconsole.console.settings.menu.item.autocomplete.tooltip=Os fyddwch yn galluogi'r dewis hwn, bydd y mewnbwn yn dangos awgrymiadau wrth i chi deipio ynddo
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.enablePersistentLogs.label)
+webconsole.console.settings.menu.item.enablePersistentLogs.label=Cofnodion Parhaus
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.enablePersistentLogs.tooltip)
+webconsole.console.settings.menu.item.enablePersistentLogs.tooltip=Os ydych wedi galluogi'r dewis hwn ni fydd yr allbwn yn cael ei glirio bob tro fyddwch yn symud i dudalen newydd
+
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.instantEvaluation.label)
+webconsole.console.settings.menu.item.instantEvaluation.label=Gwerthuso ar Unwaith
+# LOCALIZATION NOTE (webconsole.console.settings.menu.item.instantEvaluation.tooltip)
+webconsole.console.settings.menu.item.instantEvaluation.tooltip=Os ydych yn galluogi'r dewis hwn, bydd y mewnbwn yn cael ei werthuso ar unwaith wrth i chi deipio ynddo
+
+# LOCALIZATION NOTE (browserconsole.contentMessagesCheckbox.label)
+# Label used in the browser console filter bar. This label is used for a checkbox that
+# allows the user to show or hide console messages from the content process in the browser
+# console.
+browserconsole.contentMessagesCheckbox.label=Dangos Negeseuon Cynnwys
+# LOCALIZATION NOTE (browserconsole.contentMessagesCheckbox.tooltip)
+# Tooltip for the "Show content messages" checkbox in the Browser Console filter bar.
+browserconsole.contentMessagesCheckbox.tooltip=Galluogi hyn i ddangos negeseuon o'r broses gynnwys yn yr allbwn
+
+# LOCALIZATION NOTE (webconsole.navigated): this string is used in the console when the
+# current inspected page is navigated to a new location.
+# Parameters: %S is the new URL.
+webconsole.navigated=Wedi mynd i %S
+
+# LOCALIZATION NOTE (webconsole.closeSplitConsoleButton.tooltip): This is the tooltip for
+# the close button of the split console.
+webconsole.closeSplitConsoleButton.tooltip=Cau Consol Hollt (Esc)
+
+# LOCALIZATION NOTE (webconsole.closeSidebarButton.tooltip): This is the tooltip for
+# the close button of the sidebar.
+webconsole.closeSidebarButton.tooltip=Cau Bar Ochr
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.input.placeHolder):
+# This string is displayed in the placeholder of the reverse search input in the console.
+webconsole.reverseSearch.input.placeHolder=Hanes chwilio
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.result.closeButton.tooltip):
+# This string is displayed in the tooltip of the close button in the reverse search toolbar.
+# A keyboard shortcut will be shown inside the latter pair of brackets.
+webconsole.reverseSearch.closeButton.tooltip=Cau (%S)
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.results):
+# This string is displayed in the reverse search UI when there are at least one result
+# to the search.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 index of current search result displayed.
+# #2 total number of search results.
+webconsole.reverseSearch.results=1 canlyniad;#1 o #2 canlyniad;#1 o #2 canlyniad;#1 o #2 canlyniad;#1 o #2 canlyniad;#1 o #2 canlyniad
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.noResult):
+# This string is displayed in the reverse search UI when there is no results to the search.
+webconsole.reverseSearch.noResult=Dim canlyniad
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.result.previousButton.tooltip):
+# This string is displayed in the tooltip of the "previous result" button in the reverse search toolbar.
+# A keyboard shortcut will be shown inside the latter pair of brackets.
+webconsole.reverseSearch.result.previousButton.tooltip=Canlyniad blaenorol (%S)
+
+# LOCALIZATION NOTE (webconsole.reverseSearch.result.nextButton.tooltip):
+# This string is displayed in the tooltip of the "next result" button in the reverse search toolbar.
+# A keyboard shortcut will be shown inside the latter pair of brackets.
+webconsole.reverseSearch.result.nextButton.tooltip=Canlyniad nesaf (%S)
+
+# LOCALIZATION NOTE (webconsole.confirmDialog.getter.label)
+# Label used for the "invoke getter" confirm dialog that appears in the console when
+# a user tries to autocomplete a property with a getter.
+# Example: given the following object `x = {get y() {}}`, when the user types `x.y.`, it
+# would return "Invoke getter y to retrieve the property list?".
+# Parameters: %S is the name of the getter.
+webconsole.confirmDialog.getter.label=Cychwyn getter %S i estyn y rhestr priodwedd?
+
+# LOCALIZATION NOTE (webconsole.confirmDialog.getter.invokeButtonLabelWithShortcut)
+# Label used for the confirm button in the "invoke getter" dialog that appears in the
+# console when a user tries to autocomplete a property with a getter.
+# A keyboard shortcut will be shown inside the latter pair of brackets.
+webconsole.confirmDialog.getter.invokeButtonLabelWithShortcut=Cychwyn (%S)
+
+# LOCALIZATION NOTE (webconsole.confirmDialog.getter.closeButton.tooltip)
+# Label used as the tooltip for the close  button in the "invoke getter" dialog that
+# appears in the console when a user tries to autocomplete a property with a getter.
+# A keyboard shortcut will be shown inside the latter pair of brackets.
+webconsole.confirmDialog.getter.closeButton.tooltip=Cau (%S)
+
+# LOCALIZATION NOTE (webconsole.cssWarningElements.label)
+# Label for the list of HTML elements matching the selector associated
+# with the CSS warning. Parameters: %S is the CSS selector.
+webconsole.cssWarningElements.label=Elfennau sy'n cyfateb i'r detholwr: %S
+
+# LOCALIZATION NOTE (webconsole.message.componentDidCatch.label)
+# Label displayed when the webconsole couldn't handle a given packet.
+# Parameters: %S is the URL to file a bug about the error.
+webconsole.message.componentDidCatch.label=[DEVTOOLS ERROR] Mae'n ddrwg gennym, nid oedd modd i ni rendro'r neges. Dylai hyn ddim fod wedi digwydd - ffeiliwch wall yn %S gyda metadata'r neges yn y disgrifiad.
+
+# LOCALIZATION NOTE (webconsole.message.commands.blockedURL)
+# Label displayed when the :block <url> command is successful
+# Parameters: %S is the URL filter
+webconsole.message.commands.blockedURL=Mae ceisiadau i URL sy'n cynnwys “%S” bellach wedi'u rhwystro
+
+# LOCALIZATION NOTE (webconsole.message.commands.unblockedURL)
+# Label displayed when the :unblock <url> command is successful
+# Parameters: %S is the URL filter
+webconsole.message.commands.unblockedURL=Hidlydd rhwystro “%S” wedi'i dynnu
+
+# LOCALIZATION NOTE (webconsole.messages.commands.blockArgMissing)
+# Message displayed when no filter is passed to block/unblock command
+webconsole.messages.commands.blockArgMissing=Hidlydd heb ei bennu
+
+# LOCALIZATION NOTE (webconsole.message.componentDidCatch.copyButton.label)
+# Label displayed on the button next to the message we display when the webconsole
+# couldn't handle a given packet (See webconsole.message.componentDidCatch.label).
+webconsole.message.componentDidCatch.copyButton.label=Copïo metadata'r neges i'r clipfwrdd
+
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.executeButton.label)
+# Label used for the text of the execute button, in the editor toolbar, which is
+# displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+webconsole.editor.toolbar.executeButton.label=Rhedeg
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.reverseSearchButton.openReverseSearch.tooltip)
+# Label used for the tooltip on the reverse search button for opening the Reverse Search UI.
+# The Reverse Search is a feature that mimics the bash-like reverse search of
+# command history in WebConsole, searching commands from the last item backwards.
+# Parameters: %S is the keyboard shortcut.
+webconsole.editor.toolbar.reverseSearchButton.openReverseSearch.tooltip=Agor Chwilio Gwrthdroi Hanes (%S)
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.reverseSearchButton.closeReverseSearch.tooltip)
+# Label used for the tooltip on the reverse search button for closing the Reverse Search UI.
+# The Reverse Search is a feature that mimics the bash-like reverse search of
+# command history in WebConsole, searching commands from the last item backwards.
+# Parameters: %S is the keyboard shortcut.
+webconsole.editor.toolbar.reverseSearchButton.closeReverseSearch.tooltip=Cau Chwilio Gwrthdroi Hanes (%S)
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.executeButton.tooltip)
+# Label used for the tooltip on the execute button, in the editor toolbar, which is
+# displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+# Parameters: %S is the keyboard shortcut.
+webconsole.editor.toolbar.executeButton.tooltip=Mynegiant rhedeg (%S). Ni fydd hyn yn clirio'r mewnbwn.
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.prettyPrintButton.tooltip)
+# Label used for the tooltip on the prettyPrint button, in the editor toolbar, which is
+# displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+webconsole.editor.toolbar.prettyPrintButton.tooltip=Mynegiad prettyPrint
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.executeButton.tooltip)
+# Label used for the tooltip on the history previous expression, in the editor toolbar,
+# which is displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+webconsole.editor.toolbar.history.prevExpressionButton.tooltip=Mynegiant Blaenorol
+
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.executeButton.tooltip)
+# Label used for the tooltip on the history next expression, in the editor toolbar,
+# which is displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+webconsole.editor.toolbar.history.nextExpressionButton.tooltip=Mynegiant Nesaf
+
+# LOCALIZATION NOTE (webconsole.editor.toolbar.closeButton.tooltip2)
+# Label used for the tooltip on the close button, in the editor toolbar, which is
+# displayed when the editor mode is enabled (devtools.webconsole.input.editor=true).
+# Parameters: %S is the keyboard shortcut.
+webconsole.editor.toolbar.closeButton.tooltip2=Newid nôl i'r modd mewnlin (%S)
+
+# LOCALIZATION NOTE (webconsole.input.openEditorButton.tooltip2)
+# Label used for the tooltip on the open editor button, in console input, which is
+# displayed when the console is in regular mode.
+# Parameters: %S is the keyboard shortcut.
+webconsole.input.openEditorButton.tooltip2=Newid i'r modd golygydd aml-linell (%S)
+
+# LOCALIZATION NOTE (webconsole.warningGroup.messageCount.tooltip): the tooltip text
+# displayed when you hover a warning group badge (i.e. repeated warning messages for a
+# given category, for example Content Blocked messages) in the web console output.
+# This is a semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of message in the group.
+# example: 3 messages
+webconsole.warningGroup.messageCount.tooltip=#1 neges:#1 neges;#1 neges;#1 neges;#1 neges;#1 neges;#1 neges
+
+# LOCALIZATION NOTE (webconsole.input.editor.onboarding.label): the text that is displayed
+# when displaying the multiline-input mode for the first time, until the user dismiss the
+# text.
+# Parameters: %1$S is Enter key, %2$S is the shorcut to evaluate the expression (
+# Ctrl+Enter or Cmd+Enter on OSX).
+webconsole.input.editor.onboarding.label=Iteru eich cod yn gyflymach gyda'r modd golygydd aml-linell newydd. Defnyddiwch%1$S i ychwanegu llinellau newydd a %2$S i'w redeg.
+
+# LOCALIZATION NOTE (webconsole.input.editor.onboarding.dismiss.label): the text that is
+# displayed in the multiline-input mode onboarding UI to dismiss it.
+webconsole.input.editor.onboarding.dismiss.label=Iawn, rwy'n deall!
+
+# LOCALIZATION NOTE (webconsole.enterKey): The text that will be used to represent the
+# Enter key in the editor onboarding UI, as well as on the Editor toolbar "Run" button
+# tooltip.
+webconsole.enterKey=Enter
+
+# LOCALIZATION NOTE (webconsole.input.openJavaScriptFile): This is a label
+# used for opening a file in the console input (Ctrl+O or Cmd+O on OSX while
+# being focused on the input).
+webconsole.input.openJavaScriptFile=Agor Ffeil JavaScript
+
+# LOCALIZATION NOTE (webconsole.input.openJavaScriptFileFilter):
+# This string is displayed as a filter when opening a file in the console input.
+webconsole.input.openJavaScriptFileFilter=Ffeiliau JavaScript
+
+# LOCALIZATION NOTE (webconsole.input.selector.top): This is the term used
+# to describe the primary thread of execution in the page
+webconsole.input.selector.top=Brig
+
+# LOCALIZATION NOTE (webconsole.input.selector.tooltip): This is the tooltip
+# shown when users select a thread that they want to evaluate an
+# expression for.
+webconsole.input.selector.tooltip=Dewis cyd-destun gwerthuso
+
+# LOCALIZATION NOTE (webconsole.group.cookieSameSiteLaxByDefaultEnabled): do not translate 'sameSite'.
+webconsole.group.cookieSameSiteLaxByDefaultEnabled=Mae rhai cwcis yn camddefnyddio'r priodoledd “sameSite”, felly nid yw'n gweithio yn ôl y disgwyl
+# LOCALIZATION NOTE (webconsole.group.cookieSameSiteLaxByDefaultDisabled): do not translate 'sameSite'.
+webconsole.group.cookieSameSiteLaxByDefaultDisabled=Mae rhai cwcis yn camddefnyddio'r priodoledd “sameSite” sy'n cael ei argymell
+
+# LOCALIZATION NOTE (webconsole.group.cookieSameSiteLaxByDefaultEnabled2): do not translate 'SameSite'.
+webconsole.group.cookieSameSiteLaxByDefaultEnabled2=Mae rhai cwcis yn camddefnyddio'r priodoledd “SameSite”, felly nid yw'n gweithio yn ôl y disgwyl
+# LOCALIZATION NOTE (webconsole.group.cookieSameSiteLaxByDefaultDisabled2): do not translate 'SameSite'.
+webconsole.group.cookieSameSiteLaxByDefaultDisabled2=Mae rhai cwcis yn camddefnyddio'r priodoledd “SameSite” sy'n cael ei argymell
diff --git a/l10n-cy/devtools/shared/accessibility.properties b/l10n-cy/devtools/shared/accessibility.properties
new file mode 100644
index 0000000000..42226199ee
--- /dev/null
+++ b/l10n-cy/devtools/shared/accessibility.properties
@@ -0,0 +1,142 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (accessibility.contrast.ratio): A title text for the color contrast
+# ratio description, used by the accessibility highlighter to display the value. %S in the
+# content will be replaced by the contrast ratio numerical value.
+accessibility.contrast.ratio=Cydraniad: %S
+
+# LOCALIZATION NOTE (accessibility.contrast.ratio.error): A title text for the color
+# contrast ratio, used when the tool is unable to calculate the contrast ratio value.
+accessibility.contrast.ratio.error=Methu cyfrifo
+
+# LOCALIZATION NOTE (accessibility.contrast.ratio.label): A title text for the color
+# contrast ratio description, used together with the actual values.
+accessibility.contrast.ratio.label=Cyferbyniad:
+
+# LOCALIZATION NOTE (accessibility.contrast.ratio.label.large): A title text for the color
+# contrast ratio description that also specifies that the color contrast criteria used is
+# if for large text.
+accessibility.contrast.ratio.label.large=Cyferbyniad (testun mawr):
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.area): A title text that
+# describes that currently selected accessible object for an <area> element must have
+# its name provided via the alt attribute.
+accessibility.text.label.issue.area = Defnyddiwch briodoledd “alt” i labelu elfennau “ardal” sydd â'r priodoledd “href”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.dialog): A title text that
+# describes that currently selected accessible object for a dialog should have a name
+# provided.
+accessibility.text.label.issue.dialog = Rhaid labelu deialogau.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.document.title): A title text that
+# describes that currently selected accessible object for a document must have a name
+# provided via title.
+accessibility.text.label.issue.document.title = Rhaid i ddogfennau feddu ar deitl.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.embed): A title text that
+# describes that currently selected accessible object for an <embed> must have a name
+# provided.
+accessibility.text.label.issue.embed = Rhaid labelu cynnwys wedi'i fewnblannu.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.figure): A title text that
+# describes that currently selected accessible object for a figure should have a name
+# provided.
+accessibility.text.label.issue.figure = Rhaid labelu ffigurau gyda chapsiynau dewisol.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.fieldset): A title text that
+# describes that currently selected accessible object for a <fieldset> must have a name
+# provided.
+accessibility.text.label.issue.fieldset = Rhaid labelu elfennau “fieldset”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.fieldset.legend2): A title text that
+# describes that currently selected accessible object for a <fieldset> must have a name
+# provided via <legend> element.
+accessibility.text.label.issue.fieldset.legend2 = Defnyddiwch yr elfen “legend” i labelu elfennau “fieldset”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.form): A title text that
+# describes that currently selected accessible object for a form element must have a name
+# provided.
+accessibility.text.label.issue.form = Rhaid labelu elfennau ffurflen.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.form.visible): A title text that
+# describes that currently selected accessible object for a form element should have a name
+# provided via a visible label/element.
+accessibility.text.label.issue.form.visible = Dylai fod gan elfennau ffurflenni label testun gweladwy.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.frame): A title text that
+# describes that currently selected accessible object for a <frame> must have a name
+# provided.
+accessibility.text.label.issue.frame = Rhaid labelu elfennau “frame”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.glyph): A title text that
+# describes that currently selected accessible object for a <mglyph> must have a name
+# provided via alt attribute.
+accessibility.text.label.issue.glyph = Defnyddiwch briodoledd “alt” i labelu elfennau “mglyph”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.heading): A title text that
+# describes that currently selected accessible object for a heading must have a name
+# provided.
+accessibility.text.label.issue.heading = Rhaid labelu'r penawdau.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.heading.content): A title text that
+# describes that currently selected accessible object for a heading must have visible
+# content.
+accessibility.text.label.issue.heading.content = Dylai penawdau gynnwys testun gweladwy.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.iframe): A title text that
+# describes that currently selected accessible object for an <iframe> have a name
+# provided via title attribute.
+accessibility.text.label.issue.iframe = Defnyddiwch briodoledd “teitl” i ddisgrifio cynnwys “iframe”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.image): A title text that
+# describes that currently selected accessible object for graphical content must have a
+# name provided.
+accessibility.text.label.issue.image = Rhaid labelu cynnwys gyda delweddau.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.interactive): A title text that
+# describes that currently selected accessible object for interactive element must have a
+# name provided.
+accessibility.text.label.issue.interactive = Rhaid labelu elfennau rhyngweithiol.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.optgroup.label2): A title text that
+# describes that currently selected accessible object for an <optgroup> must have a
+# name provided via label attribute.
+accessibility.text.label.issue.optgroup.label2 = Defnyddiwch briodoledd “label” i labelu elfennau “optgroup”.
+
+# LOCALIZATION NOTE (accessibility.text.label.issue.toolbar): A title text that
+# describes that currently selected accessible object for a toolbar must have a
+# name provided when there is more than one toolbar in the document.
+accessibility.text.label.issue.toolbar = Rhaid labelu bariau offer pan fydd mwy nag un bar offer.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.semantics): A title text that
+# describes that currently selected accessible object is focusable and should
+# indicate that it could be interacted with.
+accessibility.keyboard.issue.semantics=Dylai elfennau ffocwsadwy fod â semanteg ryngweithiol.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.tabindex): A title text that
+# describes that currently selected accessible object has a corresponding
+# DOMNode that defines a tabindex attribute greater that 0 which can result in
+# unexpected behaviour when navigating with keyboard.
+accessibility.keyboard.issue.tabindex=Ceisiwch osgoi defnyddio priodoledd “tabindex” sy'n fwy na sero.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.action): A title text that
+# describes that currently selected accessible object is interactive but can not
+# be activated using keyboard or accessibility API.
+accessibility.keyboard.issue.action=Rhaid gallu actifadu elfennau rhyngweithiol gan ddefnyddio bysellfwrdd.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.focusable): A title text that
+# describes that currently selected accessible object is interactive but is not
+# focusable with a keyboard.
+accessibility.keyboard.issue.focusable=Rhaid labelu elfennau ffocwsadwy.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.focus.visible): A title text
+# that describes that currently selected accessible object is focusable but
+# might not have appropriate focus styling.
+accessibility.keyboard.issue.focus.visible=Efallai bod elfen ffocwsadwy yn brin o arddull ffocws.
+
+# LOCALIZATION NOTE (accessibility.keyboard.issue.mouse.only): A title text that
+# describes that currently selected accessible object is not focusable and not
+# semantic but can be activated via mouse (e.g. has click handler).
+accessibility.keyboard.issue.mouse.only=Dylai elfennau clicadwy fod yn ffocwsadwy a bod â semanteg rhyngweithiol.
diff --git a/l10n-cy/devtools/shared/debugger.properties b/l10n-cy/devtools/shared/debugger.properties
new file mode 100644
index 0000000000..f7add98d7a
--- /dev/null
+++ b/l10n-cy/devtools/shared/debugger.properties
@@ -0,0 +1,59 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Debugger
+# which is available from the Web Developer sub-menu -> 'Debugger'.
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (remoteIncomingPromptTitle): The title displayed on the
+# dialog that prompts the user to allow the incoming connection.
+remoteIncomingPromptTitle=Cysylltiad i Mewn
+
+# LOCALIZATION NOTE (remoteIncomingPromptHeader): Header displayed on the
+# dialog that prompts the user to allow the incoming connection.
+remoteIncomingPromptHeader=Canfuwyd cais i mewn i ganiatáu cysylltiad dadfygio pell. Gall cleient pell gymryd reolaeth lwyr o'ch porwr!
+# LOCALIZATION NOTE (remoteIncomingPromptClientEndpoint): Part of the prompt
+# dialog for the user to choose whether an incoming connection should be
+# allowed.
+# %1$S: The host and port of the client such as "127.0.0.1:6000"
+remoteIncomingPromptClientEndpoint=Diweddbwynt Cleient: %1$S
+# LOCALIZATION NOTE (remoteIncomingPromptServerEndpoint): Part of the prompt
+# dialog for the user to choose whether an incoming connection should be
+# allowed.
+# %1$S: The host and port of the server such as "127.0.0.1:6000"
+remoteIncomingPromptServerEndpoint=Diweddbwynt Gweinydd: %1$S
+# LOCALIZATION NOTE (remoteIncomingPromptFooter): Footer displayed on the
+# dialog that prompts the user to allow the incoming connection.
+remoteIncomingPromptFooter=Caniatáu'r cysylltiad?
+
+# LOCALIZATION NOTE (remoteIncomingPromptDisable): The label displayed on the
+# third button in the incoming connection dialog that lets the user disable the
+# remote debugger server.
+remoteIncomingPromptDisable=Anablu
+
+# LOCALIZATION NOTE (clientSendOOBTitle): The title displayed on the dialog that
+# instructs the user to transfer an authentication token to the server.
+clientSendOOBTitle=Enw cleient
+# LOCALIZATION NOTE (clientSendOOBHeader): Header displayed on the dialog that
+# instructs the user to transfer an authentication token to the server.
+clientSendOOBHeader=Mae'r diweddbwynt rydych yn cysylltu â hi angen mwy o wybodaeth i ddilysu'r cysylltiad hwn.  Darparwch y tocyn isod yn yr anogwr sy'n ymddangos ar y pen arall.
+# LOCALIZATION NOTE (clientSendOOBHash): Part of the dialog that instructs the
+# user to transfer an authentication token to the server.
+# %1$S: The client's cert fingerprint
+clientSendOOBHash=My Cert: %1$S
+# LOCALIZATION NOTE (clientSendOOBToken): Part of the dialog that instructs the
+# user to transfer an authentication token to the server.
+# %1$S: The authentication token that the user will transfer.
+clientSendOOBToken=Tocyn: %1$S
+
+# LOCALIZATION NOTE (serverReceiveOOBTitle): The title displayed on the dialog
+# that instructs the user to provide an authentication token from the client.
+serverReceiveOOBTitle=Darparwch Docyn Cleient
+# LOCALIZATION NOTE (serverReceiveOOBBody): Main text displayed on the dialog
+# that instructs the user to provide an authentication token from the client.
+serverReceiveOOBBody=Dylai'r cleient fod yn dangos gwerth tocyn.  Rhowch werth y tocyn yma i gwblhau dilysiad y cleient hwn.
diff --git a/l10n-cy/devtools/shared/eyedropper.properties b/l10n-cy/devtools/shared/eyedropper.properties
new file mode 100644
index 0000000000..35f20c53b1
--- /dev/null
+++ b/l10n-cy/devtools/shared/eyedropper.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used in the Eyedropper color tool.
+# LOCALIZATION NOTE The correct localization of this file might be to keep it
+# in English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best documentation
+# on web development on the web.
+
+# LOCALIZATION NOTE  (colorValue.copied): This text is displayed when the user selects a
+# color with the eyedropper and it's copied to the clipboard.
+colorValue.copied=copïwyd
diff --git a/l10n-cy/devtools/shared/highlighters.properties b/l10n-cy/devtools/shared/highlighters.properties
new file mode 100644
index 0000000000..62256f7b45
--- /dev/null
+++ b/l10n-cy/devtools/shared/highlighters.properties
@@ -0,0 +1,35 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE This file contains strings used in highlighters.
+# Highlighters are visualizations that DevTools draws on top of content to aid
+# in understanding content sizing, etc.
+
+# LOCALIZATION NOTE (grid.rowColumnPositions): The row and column position of a grid
+# cell shown in the grid cell infobar when hovering over the CSS grid outline.
+grid.rowColumnPositions=Rhes %S / Colofn %S
+
+# LOCALIZATION NOTE (gridType.container): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is a grid container.
+gridType.container=Cynhwysydd Grid
+
+# LOCALIZATION NOTE (gridType.item): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is a grid item.
+gridType.item=Eitem Grid
+
+# LOCALIZATION NOTE (gridType.dual): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is both a grid container and a grid item.
+gridType.dual=Cynhwysydd Grid/Item
+
+# LOCALIZATION NOTE (flexType.container): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is a flex container.
+flexType.container=Cynhwysydd Flex
+
+# LOCALIZATION NOTE (flexType.item): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is a flex item.
+flexType.item=Eitem Flex
+
+# LOCALIZATION NOTE (flexType.dual): the layout type of an element shown in
+# the infobar when hovering over a DOM element and it is both a flex container and a flex item.
+flexType.dual=Cynhwysydd Flex/Item
diff --git a/l10n-cy/devtools/shared/screenshot.properties b/l10n-cy/devtools/shared/screenshot.properties
new file mode 100644
index 0000000000..eecfe350f2
--- /dev/null
+++ b/l10n-cy/devtools/shared/screenshot.properties
@@ -0,0 +1,138 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside Web Console commands.
+# The Web Console command line is available from the Web Developer sub-menu
+# -> 'Web Console'.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+# LOCALIZATION NOTE (screenshotDesc) A very short description of the
+# 'screenshot' command. Displayed when the --help flag is passed to
+# the screenshot command.
+screenshotDesc=Cadw delwedd o'r dudalen
+
+# LOCALIZATION NOTE (screenshotFilenameDesc) A very short string to describe
+# the 'filename' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the screenshot command.
+screenshotFilenameDesc=Enw ffeil cyrchfan
+
+# LOCALIZATION NOTE (screenshotFilenameManual) A fuller description of the
+# 'filename' parameter to the 'screenshot' command.
+screenshotFilenameManual=Enw'r ffeil (dylai fod ag estyniad ‘.png’) y byddwn yn ysgrifennu'r llun sgrin ati.
+
+# LOCALIZATION NOTE (screenshotClipboardDesc) A very short string to describe
+# the 'clipboard' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the screenshot command.
+screenshotClipboardDesc=Copïo llun sgrin i'r clipfwrdd? (true/false)
+
+# LOCALIZATION NOTE (screenshotClipboardManual) A fuller description of the
+# 'clipboard' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the screenshot command.
+screenshotClipboardManual=True os ydych eisiau copïo'r llun sgrin yn lle ei gadw i ffeil.
+
+# LOCALIZATION NOTE (screenshotGroupOptions) A label for the optional options of
+# the screenshot command. Displayed when the --help flag is passed to the
+# screenshot command.
+screenshotGroupOptions=Dewisiadau
+
+# LOCALIZATION NOTE (screenshotDelayDesc) A very short string to describe
+# the 'delay' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the screenshot command.
+screenshotDelayDesc=Oedi (eiliadau)
+
+# LOCALIZATION NOTE (screenshotDelayManual) A fuller description of the
+# 'delay' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the screenshot command.
+screenshotDelayManual=Amser disgwyl (mewn eiliadau) cyn i'r llun sgrin gael ei gymryd
+
+# LOCALIZATION NOTE (screenshotDPRDesc) A very short string to describe
+# the 'dpr' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotDPRDesc=Graddfa picsel dyfais
+
+# LOCALIZATION NOTE (screenshotDPRManual) A fuller description of the
+# 'dpr' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotDPRManual=Y raddfa picsel i'w defnyddio wrth gymryd y llun sgrin
+
+# LOCALIZATION NOTE (screenshotFullPageDesc) A very short string to describe
+# the 'fullpage' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotFullPageDesc=Gwefan gyfan? (true/false)
+
+# LOCALIZATION NOTE (screenshotFullPageManual) A fuller description of the
+# 'fullpage' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotFullPageManual=True os yw'r llun sgrin yn cynnwys rhannau o'r dudalen we tu allan i gyfyngiadau'r sgrolio cyfredol.
+
+# LOCALIZATION NOTE (screenshotFileDesc) A very short string to describe
+# the 'file' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotFileDesc=Cadw i ffeil? (true/false)
+
+# LOCALIZATION NOTE (screenshotFileManual) A fuller description of the
+# 'file' parameter to the 'screenshot' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+screenshotFileManual=True os ddylai'r llun sgrin gadw'r ffeil hyd yn oed pan mae dewisiadau eraill wedi eu galluogi (e.e. clipfwrdd).
+
+# LOCALIZATION NOTE (screenshotGeneratedFilename) The auto generated filename
+# when no file name is provided. The first argument (%1$S) is the date string
+# in yyyy-mm-dd format and the second argument (%2$S) is the time string
+# in HH.MM.SS format. Please don't add the extension here.
+screenshotGeneratedFilename=Llun Sgrin %1$S yn %2$S
+
+# LOCALIZATION NOTE (screenshotErrorSavingToFile) Text displayed to user upon
+# encountering error while saving the screenshot to the file specified.
+# The argument (%1$S) is the filename.
+screenshotErrorSavingToFile=Gwall wrth gadw i %1$S
+
+# LOCALIZATION NOTE (screenshotSavedToFile) Text displayed to user when the
+# screenshot is successfully saved to the file specified.
+# The argument (%1$S) is the filename.
+screenshotSavedToFile=Cadwyd i %1$S
+
+# LOCALIZATION NOTE (screenshotErrorCopying) Text displayed to user upon
+# encountering error while copying the screenshot to clipboard.
+screenshotErrorCopying=Digwyddodd gwall wrth gopïo llun sgrin i'r clipfwrdd.
+
+# LOCALIZATION NOTE (screenshotCopied) Text displayed to user when the
+# screenshot is successfully copied to the clipboard.
+screenshotCopied=Llun sgrin wedi ei gopïo i'r clipfwrdd.
+
+# LOCALIZATION NOTE (inspectNodeDesc) A very short string to describe the
+# 'node' parameter to the 'inspect' command. Displayed when the
+# --help flag is passed to the `screenshot command.
+inspectNodeDesc=Dewisydd CSS
+
+# LOCALIZATION NOTE (inspectNodeManual) A fuller description of the 'node'
+# parameter to the 'inspect' command. Displayed when the --help flag is
+# passed to the `screenshot command.
+inspectNodeManual=Dewisydd CSS ar gyfer defnyddio gyda document.querySelector sy'n adnabod elfen unigol
+
+# LOCALIZATION NOTE (screenshotTruncationWarning) Text displayed to user when the image
+# that would be created by the screenshot is too big and needs to be truncated to avoid
+# errors.
+# The first parameter is the width of the final image and the second parameter is the
+# height of the image.
+screenshotTruncationWarning=Torrwyd y ddelwedd i %1$S×%2$S gan fod y ddelwedd a ddeilliodd ohoni yn rhy fawr
+
+# LOCALIZATION NOTE (screenshotDPRDecreasedWarning2) Text displayed to user when
+# taking the screenshot initially failed. When the Device Pixel Ratio is larger
+# than 1.0 a second try immediately after displaying this message is attempted.
+screenshotDPRDecreasedWarning=Gostyngwyd cymhareb picsel y ddyfais i 1 gan fod y ddelwedd o ganlyniad yn rhy fawr
+
+# LOCALIZATION NOTE (screenshotRenderingError) Text displayed to user upon
+# encountering an error while rendering the screenshot. This most often happens when the
+# resulting image is too large to be rendered.
+screenshotRenderingError=Gwall wrth greu'r ddelwedd. Mae'n debyg bod y ddelwedd o ganlyniad yn rhy fawr.
+
+# LOCALIZATION NOTE (screenshotNoSelectorMatchWarning) Text displayed to user when the
+# provided selector for the screenshot does not match any element on the page.
+# The argument (%1$S) is selector.
+screenshotNoSelectorMatchWarning=Nid yw’r dewisydd ‘%S’ yn cyfateb i unrhyw elfen ar y dudalen.
diff --git a/l10n-cy/devtools/shared/shared.properties b/l10n-cy/devtools/shared/shared.properties
new file mode 100644
index 0000000000..0978450dee
--- /dev/null
+++ b/l10n-cy/devtools/shared/shared.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (ellipsis): The ellipsis (three dots) character
+ellipsis=…
diff --git a/l10n-cy/devtools/shared/styleinspector.properties b/l10n-cy/devtools/shared/styleinspector.properties
new file mode 100644
index 0000000000..1afb40cdf8
--- /dev/null
+++ b/l10n-cy/devtools/shared/styleinspector.properties
@@ -0,0 +1,242 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE These strings are used inside the Style Inspector.
+#
+# The correct localization of this file might be to keep it in
+# English, or another language commonly spoken among web developers.
+# You want to make that choice consistent across the developer tools.
+# A good criteria is the language in which you'd find the best
+# documentation on web development on the web.
+
+
+# LOCALIZATION NOTE (rule.status): For each style property the panel shows
+# the rules which hold that specific property. For every rule, the rule status
+# is also displayed: a rule can be the best match, a match, a parent match, or a
+# rule did not match the element the user has highlighted.
+rule.status.BEST=Cydweddiad Gorau
+rule.status.MATCHED=Cydweddwyd
+rule.status.PARENT_MATCH=Cydweddiad Rhiant
+
+# LOCALIZATION NOTE (rule.sourceElement, rule.sourceInline): For each
+# style property the panel shows the rules which hold that specific property.
+# For every rule, the rule source is also displayed: a rule can come from a
+# file, from the same page (inline), or from the element itself (element).
+rule.sourceInline=mewnlin
+rule.sourceElement=elfen
+
+# LOCALIZATION NOTE (rule.inheritedFrom): Shown for CSS rules
+# that were inherited from a parent node. Will be passed a node
+# identifier of the parent node.
+# e.g "Inherited from body#bodyID"
+rule.inheritedFrom=Etifeddwyd gan %S
+
+# LOCALIZATION NOTE (rule.keyframe): Shown for CSS Rules keyframe header.
+# Will be passed an identifier of the keyframe animation name.
+rule.keyframe=Fframiau allwedd %S
+
+# LOCALIZATION NOTE (rule.userAgentStyles): Shown next to the style sheet
+# link for CSS rules that were loaded from a user agent style sheet.
+# These styles will not be editable, and will only be visible if the
+# devtools.inspector.showUserAgentStyles pref is true.
+rule.userAgentStyles=(asiant defnyddiwr)
+
+# LOCALIZATION NOTE (rule.pseudoElement): Shown for CSS rules
+# pseudo element header
+rule.pseudoElement=Ffug-elfennau
+
+# LOCALIZATION NOTE (rule.selectedElement): Shown for CSS rules element header if
+# pseudo elements are present in the rule view.
+rule.selectedElement=Yr Elfen Hon
+
+# LOCALIZATION NOTE (rule.warning.title): When an invalid property value is
+# entered into the rule view a warning icon is displayed. This text is used for
+# the title attribute of the warning icon.
+rule.warning.title=Gwerth priodwedd annilys
+
+# LOCALIZATION NOTE (rule.warningName.title): When an invalid property name is
+# entered into the rule view a warning icon is displayed. This text is used for
+# the title attribute of the warning icon.
+rule.warningName.title=Enw priodoledd annilys
+
+# LOCALIZATION NOTE (rule.filterProperty.title): Text displayed in the tooltip
+# of the search button that is shown next to a property that has been overridden
+# in the rule view.
+rule.filterProperty.title=Rheolau’r hidl sy'n cynnwys y polisi
+
+# LOCALIZATION NOTE (rule.empty): Text displayed when the highlighter is
+# first opened and there's no node selected in the rule view.
+rule.empty=Heb ddewis elfen.
+
+# LOCALIZATION NOTE (rule.variableValue): Text displayed in a tooltip
+# when the mouse is over a variable use (like "var(--something)") in
+# the rule view.  The first argument is the variable name and the
+# second argument is the value.
+rule.variableValue=%S = %S
+
+# LOCALIZATION NOTE (rule.variableUnset): Text displayed in a tooltip
+# when the mouse is over a variable use (like "var(--something)"),
+# where the variable is not set.  the rule view.  The argument is the
+# variable name.
+rule.variableUnset=Nid yw %S wedi ei osod
+
+# LOCALIZATION NOTE (rule.selectorHighlighter.tooltip): Text displayed in a
+# tooltip when the mouse is over a selector highlighter icon in the rule view.
+rule.selectorHighlighter.tooltip=Amlygu'r holl elfennau sy'n cydweddu â'r dewis hwn
+
+# LOCALIZATION NOTE (rule.colorSwatch.tooltip): Text displayed in a tooltip
+# when the mouse is over a color swatch in the rule view.
+rule.colorSwatch.tooltip=Cliciwch i agor y dewisydd lliw shift+clic i newid lliw'r fformat
+
+# LOCALIZATION NOTE (rule.bezierSwatch.tooltip): Text displayed in a tooltip
+# when the mouse is over a cubic-bezier swatch in the rule view.
+rule.bezierSwatch.tooltip=Cliciwch i agor golygydd y swyddogaeth amseru
+
+# LOCALIZATION NOTE (rule.filterSwatch.tooltip): Text displayed in a tooltip
+# when the mouse is over a filter swatch in the rule view.
+rule.filterSwatch.tooltip=Cliciwch i agor y golygydd hidlo
+
+# LOCALIZATION NOTE (rule.angleSwatch.tooltip): Text displayed in a tooltip
+# when the mouse is over a angle swatch in the rule view.
+rule.angleSwatch.tooltip=Shift+clic i newid y fformat onglog
+
+# LOCALIZATION NOTE (rule.flexToggle.tooltip): Text displayed in a tooltip
+# when the mouse is over a Flexbox toggle icon in the rule view.
+rule.flexToggle.tooltip=Cliciwch i doglo amlygydd Flexbox
+
+# LOCALIZATION NOTE (rule.gridToggle.tooltip): Text displayed in a tooltip
+# when the mouse is over a CSS Grid toggle icon in the rule view.
+rule.gridToggle.tooltip=Cliciwch i doglo amlygwr Grid CSS
+
+# LOCALIZATION NOTE (rule.filterStyles.placeholder): This is the placeholder that
+# goes in the search box when no search term has been entered.
+rule.filterStyles.placeholder=Arddulliau Hidlau
+
+# LOCALIZATION NOTE (rule.addRule.tooltip): This is the tooltip shown when
+# hovering the `Add new rule` button in the rules view toolbar.
+rule.addRule.tooltip=Ychwanegu rheol newydd
+
+# LOCALIZATION NOTE (rule.togglePseudo.tooltip): This is the tooltip
+# shown when hovering over the `Toggle Pseudo Class Panel` button in the
+# rule view toolbar.
+rule.togglePseudo.tooltip=Toglo dosbarthiadau ffug
+
+# LOCALIZATION NOTE (rule.classPanel.toggleClass.tooltip): This is the tooltip
+# shown when hovering over the `Toggle Class Panel` button in the
+# rule view toolbar.
+rule.classPanel.toggleClass.tooltip=Toglo dosbarthiadau
+
+# LOCALIZATION NOTE (rule.classPanel.newClass.placeholder): This is the placeholder
+# shown inside the text field used to add a new class in the rule-view.
+rule.classPanel.newClass.placeholder=Ychwanegu dosbarth newydd
+
+# LOCALIZATION NOTE (rule.classPanel.noClasses): This is the text displayed in the
+# class panel when the current element has no classes applied.
+rule.classPanel.noClasses=Dim dosbarthiadau yn yr elfen hon
+
+# LOCALIZATION NOTE (rule.printSimulation.tooltip):
+# This is the tooltip of the print simulation button in the Rule View toolbar
+# that toggles print simulation.
+rule.printSimulation.tooltip=Toggle efelychu cyfryngau print ar gyfer y dudalen
+
+# LOCALIZATION NOTE (rule.colorSchemeSimulation.tooltip):
+# This is the tooltip of the color scheme simulation button in the Rule View
+# toolbar that toggles color-scheme simulation.
+rule.colorSchemeSimulation.tooltip=Toglo efelychiad cynllun lliw'r dudalen
+
+# LOCALIZATION NOTE (rule.twistyCollapse.label): The text a screen reader
+# speaks when the header of a rule is expanded.
+rule.twistyCollapse.label=Cau
+
+# LOCALIZATION NOTE (rule.twistyExpand.label): The text a screen reader
+# speaks when the header of a rule is collapsed.
+rule.twistyExpand.label=Ehangu
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyColor): Text displayed in the rule
+# and computed view context menu when a color value was clicked.
+styleinspector.contextmenu.copyColor=Copïo Lliw
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyColor.accessKey): Access key for
+# the rule and computed view context menu "Copy Color" entry.
+styleinspector.contextmenu.copyColor.accessKey=L
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyUrl): In rule and computed view :
+# text displayed in the context menu for an image URL.
+# Clicking it copies the URL to the clipboard of the user.
+styleinspector.contextmenu.copyUrl=Copïo URL
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyUrl.accessKey): Access key for
+# the rule and computed view context menu "Copy URL" entry.
+styleinspector.contextmenu.copyUrl.accessKey=U
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyImageDataUrl): In rule and computed view :
+# text displayed in the context menu for an image URL.
+# Clicking it copies the image as Data-URL to the clipboard of the user.
+styleinspector.contextmenu.copyImageDataUrl=Copïo Data Delwedd-URL
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyImageDataUrl.accessKey): Access key for
+# the rule and computed view context menu "Copy Image Data-URL" entry.
+styleinspector.contextmenu.copyImageDataUrl.accessKey=I
+
+# LOCALIZATION NOTE (styleinspector.copyImageDataUrlError): Text set in the clipboard
+# if an error occurs when using the copyImageDataUrl context menu action
+# (invalid image link, timeout, etc...)
+styleinspector.copyImageDataUrlError=Methwyd copïo delwedd Data-URL
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.toggleOrigSources): Text displayed in the rule view
+# context menu.
+styleinspector.contextmenu.toggleOrigSources=Dangos y Ffynonellau Gwreiddiol
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.toggleOrigSources.accessKey): Access key for
+# the rule view context menu "Show original sources" entry.
+styleinspector.contextmenu.toggleOrigSources.accessKey=I
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.addNewRule): Text displayed in the
+# rule view context menu for adding a new rule to the element.
+# This should match inspector.addRule.tooltip in inspector.properties
+styleinspector.contextmenu.addNewRule=Ychwanegu Rheol Newydd
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.addNewRule.accessKey): Access key for
+# the rule view context menu "Add rule" entry.
+styleinspector.contextmenu.addNewRule.accessKey=R
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.selectAll): Text displayed in the
+# computed view context menu.
+styleinspector.contextmenu.selectAll=Dewis Popeth
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.selectAll.accessKey): Access key for
+# the computed view context menu "Select all" entry.
+styleinspector.contextmenu.selectAll.accessKey=A
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copy): Text displayed in the
+# computed view context menu.
+styleinspector.contextmenu.copy=Copïo
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copy.accessKey): Access key for
+# the computed view context menu "Copy" entry.
+styleinspector.contextmenu.copy.accessKey=C
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyLocation): Text displayed in the
+# rule view context menu for copying the source location.
+styleinspector.contextmenu.copyLocation=Copïo'r Lleoliad
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyDeclaration): Text
+# displayed in the rule view context menu for copying the CSS declaration.
+styleinspector.contextmenu.copyDeclaration=Copïo'r Datganiad
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyPropertyName): Text displayed in
+# the rule view context menu for copying the property name.
+styleinspector.contextmenu.copyPropertyName=Copïo'r Enw Priodwedd
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyPropertyValue): Text displayed in
+# the rule view context menu for copying the property value.
+styleinspector.contextmenu.copyPropertyValue=Copïo'r Gwerth Priodwedd
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copyRule): Text displayed in the
+# rule view context menu for copying the rule.
+styleinspector.contextmenu.copyRule=Copïo'r Gwerth
+
+# LOCALIZATION NOTE (styleinspector.contextmenu.copySelector): Text displayed in the
+# rule view context menu for copying the selector.
+styleinspector.contextmenu.copySelector=Dewisydd Copïo
diff --git a/l10n-cy/devtools/startup/aboutDevTools.ftl b/l10n-cy/devtools/startup/aboutDevTools.ftl
new file mode 100644
index 0000000000..19f676e715
--- /dev/null
+++ b/l10n-cy/devtools/startup/aboutDevTools.ftl
@@ -0,0 +1,57 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+head-title = Ynghylch Developer Tools
+enable-title = Galluogi Firefox Developer Tools
+enable-inspect-element-title = Galluogi Firefox Developer Tools i ddefnyddio Inspect Element
+enable-inspect-element-message = Archwilio a golygu HTML a CSS gyda'r Archwiliwr Developer Tools.
+enable-about-debugging-message = Datblygu a dadfygio WebExtensions, gweithwyr gwe, gweithwyr gwasanaeth a mwy gyda Firefox Developer Tools.
+enable-key-shortcut-message = Rydych wedi cychwyn llwybr byr Developer Tools. Os oedd hynny'n gamgymeriad, gallwch gau'r tab hwn.
+enable-menu-message = Perffeithio HTML, CSS, a JavaScript eich gwefan gydag offer fel yr Archwiliwr a'r Dadfygiwr.
+enable-common-message = Mae'r Firefox Developer Tools wedi ei analluogi yn rhagosodedig i roi mwy o reolaeth i chi dros eich porwr.
+enable-learn-more-link = Dysgu rhagor am Developer Tools
+enable-enable-button = Galluogi Developer Tools
+enable-close-button = Cau'r Tab hwn
+
+welcome-title = Croeso i Firefox Developer Tools!
+newsletter-title = Mozilla Developer Newsletter
+newsletter-message = Derbyn newyddion, triciau ac adnoddau ar gyfer datblygwyr yn syth i'ch blwch derbyn.
+newsletter-email-placeholder =
+    .placeholder = E-bost
+newsletter-privacy-label = Rwy'n fodlon i Mozilla drin fy manylion fel mae'n cael ei esbonio yn <a data-l10n-name="privacy-policy">y Polisi Preifatrwydd hwn</a>.
+newsletter-subscribe-button = Tanysgrifio
+newsletter-thanks-title = Diolch!
+newsletter-thanks-message = Os nad ydych eisoes wedi cadarnhau tanysgrifiad i gylchlythyr yn perthyn i Mozilla, mae'n bosib y bydd yn rhaid i chi wneud hynny. Gwiriwch eich blwch derbyn neu eich hidl sbam am e-bost gennym ni.
+
+footer-title = Firefox Developer Edition
+footer-message = Chwilio am fwy na dim ond Developer Tools? Edrychwch ar y porwr Firefox sydd wedi ei adeiladu yn benodol ar gyfer datblygwyr a'r llif gwaith modern.
+footer-learn-more-link = Dysgu rhagor
+
+features-learn-more = Dysgu rhagor
+features-inspector-title = Archwiliwr
+features-inspector-desc = Archwilio a gwella cod er mwyn adeiladu cynlluniau picsel berffaith. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-console-title = Consol
+features-console-desc = Tracio mateion CSS, JavaScript, diogelwch a rhwydwaith. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-debugger-title = Dadfygiwr
+features-debugger-desc = Dadfygiwr JavaScript pwerus gyda chefnogaeth am eich fframwaith. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-network-title = Rhwydwaith
+features-network-desc = Monitro ceisiadau rhwydwaith sy'n gallu arafu neu rwystro eich gwefan. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-storage-title = Storfa
+features-storage-desc = Ychwanegu, newid neu dynnu data storfa dros dro, cwcis, cronfeydd data a data sesiynau. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-responsive-title = Modd Cynllunio Ymatebol
+features-responsive-desc = Profi gwefannau ar ddyfeisiau wedi eu hefelychu o fewn eich porwr. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-visual-editing-title = Golygu Gweledol
+features-visual-editing-desc = Cywiro animeiddiadau, aliniad a phadio. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-performance-title = Perfformiad
+features-performance-desc = Agor rhwystrau, llyfnhau prosesau a gwneud y mwyaf o asedau. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+features-memory-title = Cof
+features-memory-desc = Canfod colli cof a gwneud eich rhaglenni'n chwim. <a data-l10n-name="learn-more">{ features-learn-more }</a>
+# Variables:
+#   $errorDescription (String) - The error that occurred e.g. 404 - Not Found
+newsletter-error-common = Methodd cais am danysgrifiad ({ $errorDescription }).
+newsletter-error-unknown = Digwyddodd gwall annisgwyl.
+newsletter-error-timeout = Daeth y cais am danysgrifiad i ben.
+# Variables:
+#   $shortcut (String) - The keyboard shortcut used for the tool
+welcome-message = Rydych wedi galluogi Developer Tools yn llwyddiannus! I gychwyn arni, edrychwch ar ddewislen y Datblygwr Gwe neu agor yr offer gyda { $shortcut }.
diff --git a/l10n-cy/devtools/startup/key-shortcuts.properties b/l10n-cy/devtools/startup/key-shortcuts.properties
new file mode 100644
index 0000000000..a5bdf43188
--- /dev/null
+++ b/l10n-cy/devtools/startup/key-shortcuts.properties
@@ -0,0 +1,67 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (toggleToolbox.commandkey):
+# Key pressed to open a toolbox with the default panel selected
+toggleToolbox.commandkey=I
+
+# LOCALIZATION NOTE (toggleToolboxF12.commandkey):
+# Alternative key pressed to open a toolbox with the default panel selected
+toggleToolboxF12.commandkey=VK_F12
+
+# LOCALIZATION NOTE (browserToolbox.commandkey):
+# Key pressed to open the Browser Toolbox, used for debugging Firefox itself
+browserToolbox.commandkey=I
+
+# LOCALIZATION NOTE (browserConsole.commandkey):
+# Key pressed to open the Browser Console, used for debugging Firefox itself
+browserConsole.commandkey=J
+
+# LOCALIZATION NOTE (responsiveDesignMode.commandkey):
+# Key pressed to toggle on the Responsive Design Mode
+responsiveDesignMode.commandkey=M
+
+# LOCALIZATION NOTE (inspector.commandkey):
+# Key pressed to open a toolbox with the inspector panel selected
+inspector.commandkey=C
+
+# LOCALIZATION NOTE (webconsole.commandkey):
+# Key pressed to open a toolbox with the web console panel selected
+webconsole.commandkey=K
+
+# LOCALIZATION NOTE (jsdebugger.commandkey2):
+# Key pressed to open a toolbox with the debugger panel selected
+jsdebugger.commandkey2=Z
+
+# LOCALIZATION NOTE (netmonitor.commandkey):
+# Key pressed to open a toolbox with the network monitor panel selected
+netmonitor.commandkey=E
+
+# LOCALIZATION NOTE (styleeditor.commandkey):
+# Key pressed to open a toolbox with the style editor panel selected
+styleeditor.commandkey=VK_F7
+
+# LOCALIZATION NOTE (performance.commandkey):
+# Key pressed to open a toolbox with the performance panel selected
+performance.commandkey=VK_F5
+
+# LOCALIZATION NOTE (storage.commandkey):
+# Key pressed to open a toolbox with the storage panel selected
+storage.commandkey=VK_F9
+
+# LOCALIZATION NOTE (dom.commandkey):
+# Key pressed to open a toolbox with the DOM panel selected
+dom.commandkey=W
+
+# LOCALIZATION NOTE (accessibilityF12.commandkey):
+# Key pressed to open a toolbox with the accessibility panel selected
+accessibilityF12.commandkey=VK_F12
+
+# LOCALIZATION NOTE (profilerStartStop.commandkey):
+# Key pressed to start or stop the performance profiler
+profilerStartStop.commandkey=VK_1
+
+# LOCALIZATION NOTE (profilerCapture.commandkey):
+# Key pressed to capture a recorded performance profile
+profilerCapture.commandkey=VK_2
diff --git a/l10n-cy/devtools/startup/startup.properties b/l10n-cy/devtools/startup/startup.properties
new file mode 100644
index 0000000000..f323244ccc
--- /dev/null
+++ b/l10n-cy/devtools/startup/startup.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (enableDevTools.label):
+# Label for the menu item displayed in Tools > Developer Tools when DevTools are disabled.
+enableDevTools.label=Galluogi Offer Datblygwr…
+enableDevTools.accesskey=G
diff --git a/l10n-cy/dom/chrome/accessibility/AccessFu.properties b/l10n-cy/dom/chrome/accessibility/AccessFu.properties
new file mode 100644
index 0000000000..8ce1559878
--- /dev/null
+++ b/l10n-cy/dom/chrome/accessibility/AccessFu.properties
@@ -0,0 +1,360 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Screen reader started/stopped
+screenReaderStarted = Darllenydd sgrin wedi agor
+screenReaderStopped = Mae'r Darllenydd Sgrin wedi ei atal
+
+# Roles
+menubar        =       bar dewislen
+scrollbar      =       bar sgrolio
+grip           =       grip
+alert          =       rhybudd
+menupopup      =       llamlen dewislen
+document       =       dogfen
+pane           =       paen
+dialog         =       deialog
+separator      =       ymwahanydd
+toolbar        =       bar offer
+statusbar      =       bar statws
+table          =       tabl
+columnheader   =       pennyn colofn
+rowheader      =       pennyn rhes
+column         =       colofn
+row            =       rhes
+cell           =       cell
+link           =       dolen
+list           =       rhestr
+listitem       =       eitem rhestr
+outline        =       amlinell
+outlineitem    =       eitem amlinell
+pagetab        =       tab
+propertypage   =       tudalen priodwedd
+graphic        =       graffig
+switch         =       newid
+pushbutton     =       botwm
+checkbutton    =       botwm gwirio
+radiobutton    =       botwm radio
+combobox       =       blwch cyfun
+progressbar    =       bar cynnydd
+slider         =       llithrydd
+spinbutton     =       botwm troilli
+diagram        =       diagram
+animation      =       animeiddio
+equation       =       hafaliad
+buttonmenu     =       dewislen botwm
+whitespace     =       bwlch gwyn
+pagetablist    =       rhestr tabiau
+canvas         =       cynfas
+checkmenuitem  =       eitem dewislen gwirio
+label          =       label
+passwordtext   =       testun cyfrinair
+radiomenuitem  =       eitem dewislen radio
+textcontainer  =       cynhwysydd testun
+togglebutton   =       botwm toglo
+treetable      =       tabl coeden
+header         =       pennyn
+footer         =       troedyn
+paragraph      =       paragraff
+entry          =       cofnod
+caption        =       pennawd
+heading        =       pennyn
+section        =       adran
+form           =       ffurflen
+comboboxlist   =       rhestr blwch cyfun
+comboboxoption =       dewis blwch cyfun
+imagemap       =       map delwedd
+listboxoption  =       dewisol
+listbox        =       blwch rhestr
+flatequation   =       hafaliad gwastad
+gridcell       =       cell grid
+note           =       nodyn
+figure         =       ffigwr
+definitionlist =       rhestr diffiniadau
+term           =       term
+definition     =       diffiniad
+
+mathmltable              = tabl math
+mathmlcell               = cell
+mathmlenclosed           = amgau
+mathmlfraction           = ffracsiwn
+mathmlfractionwithoutbar = ffracsiwn heb far
+mathmlroot               = gwraidd
+mathmlscripted           = sgriptiwyd
+mathmlsquareroot         = ail isradd
+
+# More sophisticated roles which are not actual numeric roles
+textarea       =       ardal testun
+
+base           =       sylfaen
+close-fence    =       cau ffens
+denominator    =       enwadur
+numerator      =       rhifiadur
+open-fence     =       agor ffens
+overscript     =       trosgript
+presubscript   =       rhagis-ysgrif
+presuperscript =       rhag uwchysgrifen
+root-index     =       mynegai gwraidd
+subscript      =       isysgrif
+superscript    =       uwchysgrif
+underscript    =       tanysgrif
+
+# Text input types
+textInputType_date   =       dyddiad
+textInputType_email  =       e-bost
+textInputType_search =       chwilio
+textInputType_tel    =       ffôn
+textInputType_url    =       URL
+
+# More sophisticated object descriptions
+headingLevel   =       lefel pennyn %S
+
+# more sophisticated list announcement
+listStart      =       Eitem gyntaf
+listEnd        =       Eitem olaf
+# LOCALIZATION NOTE (listItemsCount): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+listItemsCount =       Dim eitemau;#1 eitem;#1 eitem;#1 eitem;#1 eitem;#1 eitem
+
+# LOCALIZATION NOTE: # %1$S is the position of the item n the set.
+# %2$S is the total number of such items in the set.
+# An expanded example would read "2 of 5".
+objItemOfN      =       %1$S o %2$S
+
+# Landmark announcements
+banner         =       baner
+complementary  =       cyflenwol
+contentinfo    =       gwybodaeth cynnwys
+main           =       prif
+navigation     =       symud
+search         =       chwilio
+
+region         =       ardal
+
+# LOCALIZATION NOTE (tblColumnInfo): Semi-colon list of plural forms.
+# Number of columns within the table.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+tblColumnInfo = Dim colofnau;gydag #1 colofn;gydag #1 golofn;gydag #1 colofn;gydag #1 cholofn;gydag #1 colofn
+# LOCALIZATION NOTE (tblRowInfo): Semi-colon list of plural forms.
+# Number of rows within the table or grid.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+tblRowInfo = a dim rhesi;ac #1 rhes;a #1 res;a #1 rhes;a #1 rhes;a #1 rhes
+
+# table or grid cell information
+columnInfo = Colofn %S
+rowInfo = Rhes %S
+spansColumns = estyn %S colofn
+spansRows = estyn %S rhes
+
+# Invoked actions
+jumpAction     =      neidio
+pressAction    =      pwyso
+checkAction    =      ticio
+uncheckAction  =      heb dicio
+onAction       =      ymlaen
+offAction      =      diffodd
+selectAction   =      dewiswyd
+unselectAction =      heb ddewis
+openAction     =      agor
+closeAction    =      cau
+switchAction   =      newid
+clickAction    =      clic
+collapseAction =      cauwyd
+expandAction   =      ehangwyd
+activateAction =      gweithredu
+cycleAction    =      cylchu
+
+# Live regions
+# 'hidden' will be spoken when something disappears in a live region.
+hidden         =      cudd
+
+# Tab states
+tabLoading     =      llwytho
+tabLoaded      =      llwythwyd
+tabNew         =      tab newydd
+tabLoadStopped =      llwytho wedi dod i ben
+tabReload      =      ail-lwytho
+
+# Object states
+stateChecked     =    ticiwyd
+stateOn          =    ymlaen
+stateNotChecked  =    heb eu ticio
+stateOff         =    diffodd
+statePressed     =    pwyso
+# No string for a not pressed toggle button
+stateExpanded    =    ehangwyd
+stateCollapsed   =    caewyd
+stateUnavailable =    ddim ar gael
+stateReadonly    =    darllen yn unig
+stateRequired    =    angenrheidiol
+stateTraversed   =    ymwelwyd
+stateHasPopup    =    llamlen
+stateSelected    =    dewiswyd
+
+# App modes
+editingMode    =      golygu
+navigationMode =      llywio
+
+# Quick navigation modes
+quicknav_Simple      = Rhagosodiad
+quicknav_Anchor      = Angorau
+quicknav_Button      = Botymau
+quicknav_Combobox    = Blychau cyfun
+quicknav_Landmark    = Tirnodau
+quicknav_Entry       = Cofnodion
+quicknav_FormElement = Elfennau ffurflen
+quicknav_Graphic     = Delweddau
+quicknav_Heading     = Penawdau
+quicknav_ListItem    = Eitem rhestr
+quicknav_Link        = Dolenni
+quicknav_List        = Rhestrau
+quicknav_PageTab     = Tabiau tudalen
+quicknav_RadioButton = Botwm radio
+quicknav_Separator   = Ymwahanyddion
+quicknav_Table       = Tablau
+quicknav_Checkbox    = Blychau ticio
+
+# MathML menclose notations.
+# See developer.mozilla.org/docs/Web/MathML/Element/menclose#attr-notation
+notation-longdiv            = rhaniad hir
+notation-actuarial          = ystadeg yswiriant
+notation-phasorangle        = ongl diagram gwedd
+notation-radical            = cysefin
+notation-box                = blwch
+notation-roundedbox         = blwch crwn
+notation-circle             = cylch
+notation-left               = chwith
+notation-right              = de
+notation-top                = brig
+notation-bottom             = gwaelod
+notation-updiagonalstrike   = trawiad croeslin i fyny
+notation-downdiagonalstrike = trawiad croeslin i lawr
+notation-verticalstrike     = trawiad fertigol
+notation-horizontalstrike   = trawiad llorweddol
+notation-updiagonalarrow    = saeth croeslin i fyny
+notation-madruwb            = madruwb
+
+# Shortened role names for braille
+menubarAbbr        =       bar dewislen
+scrollbarAbbr      =       bar sgrolio
+gripAbbr           =       grip
+alertAbbr          =       rhybudd
+menupopupAbbr      =       llamlen dewislen
+documentAbbr       =       dogfen
+paneAbbr           =       paen
+dialogAbbr         =       deialog
+separatorAbbr      =       ymwahanydd
+toolbarAbbr        =       bar offer
+statusbarAbbr      =       bar statws
+tableAbbr          =       tbl
+columnheaderAbbr   =       pennyn colofn
+rowheaderAbbr      =       pennyn rhes
+columnAbbr         =       colofn
+rowAbbr            =       rhes
+cellAbbr           =       cell
+linkAbbr           =       dolen
+listAbbr           =       rhestr
+listitemAbbr       =       eitem rhestr
+outlineAbbr        =       amlinell
+outlineitemAbbr    =       eitem amlinell
+pagetabAbbr        =       tab
+propertypageAbbr   =       tudalen priodwedd
+graphicAbbr        =       graffig
+pushbuttonAbbr     =       btwm
+checkbuttonAbbr    =       botwm gwirio
+radiobuttonAbbr    =       botwm radio
+comboboxAbbr       =       blwch cyfun
+progressbarAbbr    =       bar cynnydd
+sliderAbbr         =       llithrydd
+spinbuttonAbbr     =       botwm troilli
+diagramAbbr        =       diagram
+animationAbbr      =       animeiddio
+equationAbbr       =       hafaliad
+buttonmenuAbbr     =       dewislen botwm
+whitespaceAbbr     =       bwlch gwyn
+pagetablistAbbr    =       rhestr tabiau
+canvasAbbr         =       cynfas
+checkmenuitemAbbr  =       eitem dewislen gwirio
+labelAbbr          =       label
+passwordtextAbbr   =       passwdtxt
+radiomenuitemAbbr  =       eitem dewislen radio
+textcontainerAbbr  =       cynhwysydd testun
+togglebuttonAbbr   =       botwm toglo
+treetableAbbr      =       tabl coeden
+headerAbbr         =       pennyn
+footerAbbr         =       troedyn
+paragraphAbbr      =       paragraff
+entryAbbr          =       cofnod
+captionAbbr        =       pennawd
+headingAbbr        =       pennyn
+sectionAbbr        =       adran
+formAbbr           =       ffurflen
+comboboxlistAbbr   =       rhestr blwch cyfun
+comboboxoptionAbbr =       dewis blwch cyfun
+imagemapAbbr       =       imgmap
+listboxoptionAbbr  =       dewisol
+listboxAbbr        =       blwch rhestr
+flatequationAbbr   =       hafaliad gwastad
+gridcellAbbr       =       cell grid
+noteAbbr           =       nodyn
+figureAbbr         =       fig
+definitionlistAbbr =       rhestr diffiniadau
+termAbbr           =       term
+definitionAbbr     =       diffiniad
+textareaAbbr       =       ardal testun
+
+# LOCALIZATION NOTE (tblColumnInfoAbbr): Semi-colon list of plural forms.
+# Number of columns within the table.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+tblColumnInfoAbbr = 0c;#1c;#1c;#1c;#1c;#1c
+# LOCALIZATION NOTE (tblRowInfoAbbr): Semi-colon list of plural forms.
+# Number of rows within the table or grid.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+tblRowInfoAbbr = 01r;#1r;#1r;#1r;#1r;#1r
+cellInfoAbbr = c%Sr%S
+
+stateCheckedAbbr = (x)
+stateUncheckedAbbr = ( )
+statePressedAbbr = (x)
+stateUnpressedAbbr = ( )
+
+mathmlenclosedAbbr           = amgau
+mathmltableAbbr              = tbl
+mathmlcellAbbr               = cell
+mathmlfractionAbbr           = frac
+mathmlfractionwithoutbarAbbr = frac dim bar
+mathmlrootAbbr               = gwraidd
+mathmlscriptedAbbr           = sgriptiwyd
+mathmlsquarerootAbbr         = sqrt
+
+baseAbbr           = sylfaen
+close-fenceAbbr    = cau
+denominatorAbbr    = den
+numeratorAbbr      = num
+open-fenceAbbr     = agor
+overscriptAbbr     = tros
+presubscriptAbbr   = presub
+presuperscriptAbbr = presup
+root-indexAbbr     = mynegai
+subscriptAbbr      = sub
+superscriptAbbr    = sup
+underscriptAbbr    = o dan
+
+notation-longdivAbbr            = rhaniad hir
+notation-actuarialAbbr          = act
+notation-phasorangleAbbr        = phasang
+notation-radicalAbbr            = rad
+notation-boxAbbr                = blwch
+notation-roundedboxAbbr         = rndbox
+notation-circleAbbr             = circ
+notation-leftAbbr               = lft
+notation-rightAbbr              = rght
+notation-topAbbr                = brig
+notation-bottomAbbr             = bot
+notation-updiagonalstrikeAbbr   = updiagstrike
+notation-downdiagonalstrikeAbbr = dwndiagstrike
+notation-verticalstrikeAbbr     = vstrike
+notation-horizontalstrikeAbbr   = hstrike
+notation-updiagonalarrowAbbr    = updiagarrow
+notation-madruwbAbbr            = madruwb
diff --git a/l10n-cy/dom/chrome/accessibility/mac/accessible.properties b/l10n-cy/dom/chrome/accessibility/mac/accessible.properties
new file mode 100644
index 0000000000..7a75e21f53
--- /dev/null
+++ b/l10n-cy/dom/chrome/accessibility/mac/accessible.properties
@@ -0,0 +1,65 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+jump    =       Neidio
+press   =       Pwyso
+check   =       Gwiro
+uncheck =       Dad-dicio
+select  =       Dewis
+open    =       Agor
+close   =       Cau
+switch  =       Newid
+click   =       Clicio
+collapse=       Cwympo
+expand  =       Ymledu
+activate=       Gweithredu
+cycle   =       Cylchdroi
+
+# Universal Access API support
+# (Mac Only)
+# The Role Description for AXWebArea (the web widget). Like in Safari.
+htmlContent = Cynnwys HTML
+# The Role Description for the Tab button.
+tab     =       tab
+# The Role Description for definition list dl, dt and dd
+term    =       term
+definition =    diffiniad
+# The Role Description for an input type="search" text field
+searchTextField = chwilio'r maes testun
+# The Role Description for WAI-ARIA Landmarks
+application =   rhaglen
+search  =       chwilio
+banner  =       baner
+navigation =    llywio
+complementary = cyflenwol
+content =       cynnwys
+main    =       prif
+# The (spoken) role description for various WAI-ARIA roles
+alert       =      rhybudd
+alertDialog =      deialog rhybudd
+dialog      =      deialog
+article     =      erthygl
+document    =      dogfen
+# The (spoken) role description for the WAI-ARIA figure role
+# https://w3c.github.io/aria/core-aam/core-aam.html#role-map-figure
+figure     =      ffigwr
+# The (spoken) role description for the WAI-ARIA heading role
+# https://w3c.github.io/aria/core-aam/core-aam.html#role-map-heading
+heading     =      pennawd
+log         =      cofnod
+marquee     =      marquee
+math        =      math
+note        =      nodyn
+region      =      ardal
+status      =      statws y rhaglen
+timer       =      amserydd
+tooltip     =      cyngor
+separator    =      ymwahanydd
+tabPanel     =      panel tab
+# The roleDescription for the html:mark element
+highlight = amlygu
+# The roleDescription for the details element
+details = manylion
+# The roleDescription for the summary element
+summary = crynodeb
diff --git a/l10n-cy/dom/chrome/accessibility/unix/accessible.properties b/l10n-cy/dom/chrome/accessibility/unix/accessible.properties
new file mode 100644
index 0000000000..97b90e26db
--- /dev/null
+++ b/l10n-cy/dom/chrome/accessibility/unix/accessible.properties
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+jump    =       Neidio
+press   =       Pwyso
+check   =       Gwiro
+uncheck =       Dad-dicio
+select  =       Dewis
+open    =       Agor
+close   =       Cau
+switch  =       Newid
+click   =       Clicio
+collapse=       Cwympo
+expand  =       Ymledu
+activate=       Gweithredu
+cycle   =       Cylchdroi
diff --git a/l10n-cy/dom/chrome/accessibility/win/accessible.properties b/l10n-cy/dom/chrome/accessibility/win/accessible.properties
new file mode 100644
index 0000000000..97b90e26db
--- /dev/null
+++ b/l10n-cy/dom/chrome/accessibility/win/accessible.properties
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+jump    =       Neidio
+press   =       Pwyso
+check   =       Gwiro
+uncheck =       Dad-dicio
+select  =       Dewis
+open    =       Agor
+close   =       Cau
+switch  =       Newid
+click   =       Clicio
+collapse=       Cwympo
+expand  =       Ymledu
+activate=       Gweithredu
+cycle   =       Cylchdroi
diff --git a/l10n-cy/dom/chrome/appstrings.properties b/l10n-cy/dom/chrome/appstrings.properties
new file mode 100644
index 0000000000..1e6780db50
--- /dev/null
+++ b/l10n-cy/dom/chrome/appstrings.properties
@@ -0,0 +1,38 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+malformedURI2=Gwiriwch fod yr URL yn gywir a cheisiwch eto.
+fileNotFound=Nid oes modd canfod ffeil %S. Gwiriwch y lleoliad a cheisio eto.
+fileAccessDenied=Nid yw ffeil %S yn ddarllenadwy.
+dnsNotFound2=Methu canfod %S. Gwiriwch yr enw a cheisiwch eto.
+unknownProtocolFound=Nid yw un o'r canlynol (%S) yn brotocol cofrestredig ac nid yw'n cael ei ganiatáu yn y cyd-destun hwn.
+connectionFailure=Gwrthodwyd y cyswllt wrth geisio cysylltu â %S.
+netInterrupt=Daeth y cyswllt a %S i be yn annisgwyl. Mae peth data wedi ei drosglwyddo.
+netTimeout=Daeth yr amser i ben wrth geisio cysylltu â %S.
+redirectLoop=Mae'r terfyn ailgyfeirio ar gyfer yr URL wedi ei groesi.  Methu llwytho'r dudalen honno.  Gall hyn fod wedi ei achosi gan gwcis sydd wedi ei rwystro.
+confirmRepostPrompt=I ddangos y dudalen, rhaid i'r rhaglen anfon gwybodaeth sy'n ailadrodd unrhyw weithred (megis chwilio neu gadarnhad gorchymyn) gyflawnwyd ynghynt.
+resendButton.label=Ail-anfon
+unknownSocketType=Nid oes modd dangos y ddogfen heblaw eich bod yn gosod y Rheolwr Diogelwch Personol (PSM). Llwythwch a gosod PSM a cheisio eto, neu cysylltwch â'ch Gweinyddwr System.
+netReset=Nid yw'r ddogfen yn cynnwys data.
+notCached=Nid yw'r ddogfen ar gael bellach.
+netOffline=Nid oes modd dangos y ddogfen tra'n all-lein. I fynd ar-lein, dad-diciwch Gweithio All-lein yn newislen Ffeil.
+isprinting=Nid oes modd newid y ddogfen wrth Argraffu neu yn Rhagolwg Argraffu.
+deniedPortAccess=Nae mynediad at rhif y porth wedi ei analluogi am resymau diogelwch.
+proxyResolveFailure=Nid oedd modd canfod y gweinydd dirprwyol rydych wedi ei ffurfweddu. Gwiriwch eich gosodiadau a cheisio eto.
+proxyConnectFailure=Cafodd y cyswllt ei wrthod wrth geisio cysylltu â'r gweinydd dirprwyol rydych wedi ei ffurfweddu. Gwiriwch eich gosodiadau a cheisio eto.
+contentEncodingError=Methu dangos y dudalen rydych yn ceisio ei darllen am ei bod yn defnyddio math annilys a heb ei gynnal o gywasgiad.
+unsafeContentType=Methu dangos y dudalen rydych yn ceisio ei darllen am ei bod yn cynnwys math o ffeil y gall fod nad yw'n ddiogel i'w hagor. Cysylltwch â pherchennog y wefan i'w hysbysu.
+malwareBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+harmfulBlocked=Mae'r wefan, %S yn hysbys fel gwefan peryglus posib ac wedi ei rhwystro ar sail eich dewisiadau diogelwch.
+unwantedBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro ar sail eich dewisiadau diogelwch.
+deceptiveBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan twyllodrus ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+cspBlocked=Mae gan y dudalen bolisi diogelwch cynnwys sy'n ei hatal rhag cael ei llwytho yn y ffordd yma.
+xfoBlocked=Mae gan y dudalen hon bolisi X-Frame-Options sy'n ei hatal rhag cael ei lwytho yn y cyd-destun hwn.
+corruptedContentErrorv2=Mae'r wefan %S wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
+remoteXUL=Mae'r dudalen yn defnyddio technoleg nad yw'n cael ei gynnal bellach drwy ragosodiad.
+sslv3Used=Nid yw %S yn gallu gwarantu diogelwch eich data gan ei fod yn defnyddio SSLv3, protocol diogelwch sydd wedi torri.
+weakCryptoUsed=Mae perchennog %S wedi ffurfweddu ei wefan yn anghywir. I rwystro eich manylion rhag cael eu dwyn, nid yw Firefox wedi cysylltu â'r wefan.
+inadequateSecurityError=Mae'r wefan wedi ceisio negydu lefel annigonol o ddiogelwch.
+blockedByPolicy=Mae eich sefydliad wedi rhwystro mynediad i'r dudalen hon neu'r wefan.
+networkProtocolError=Mae Firefox wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
diff --git a/l10n-cy/dom/chrome/dom/dom.properties b/l10n-cy/dom/chrome/dom/dom.properties
new file mode 100644
index 0000000000..02e3b4a00d
--- /dev/null
+++ b/l10n-cy/dom/chrome/dom/dom.properties
@@ -0,0 +1,430 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+KillScriptTitle=Rhybudd: Sgript anymatebol
+KillScriptMessage=Gall fod y sgript ar y dudalen hon yn brysur, neu gall ei fod wedi peidio ymateb. Gallwch atal y sgript nawr, neu barhau i weld os fydd y sgript yn cwblhau.
+KillScriptWithDebugMessage=Gall fod sgript ar y dudalen yn brysur, neu mae wedi peidio ymateb. Gallwch atal y sgript yn awr, agor y sgript mewn dadfygiwr, neu adael i'r sgript barhau.
+KillScriptLocation=Sgript: %S
+
+KillAddonScriptTitle=Rhybudd: Sgript anymatebol yn yr ychwanegyn
+# LOCALIZATION NOTE (KillAddonScriptMessage): %1$S is the name of an extension.
+# %2$S is the name of the application (e.g., Firefox).
+KillAddonScriptMessage=Mae sgript o estyniad “%1$S” yn rhedeg ar y dudalen hon ac yn gwneud %2$S yn anymatebol.\n \nGall ei fod yn brysur neu ei fod wedi peidio ag ymateb o gwbl. Gallwch atal y sgript nawr neu barhau a gweld a fydd yn cwblhau.
+KillAddonScriptGlobalMessage=Atal estyniad y sgript rhag rhedeg ar y dudalen hon nes ei fod wedi ail lwytho
+
+StopScriptButton=Atal y sgript
+DebugScriptButton=Dadfygio'r sgript
+WaitForScriptButton=Ymlaen
+DontAskAgain=&Peidiwch gofyn i mi eto
+WindowCloseBlockedWarning=Efallai na fydd sgriptiau'n cau ffenestri nad agorwyd gan sgriptiau.
+OnBeforeUnloadTitle=Ydych chi'n siŵr?
+OnBeforeUnloadMessage=Mae'r dudalen yn gofyn i chi gadarnhau eich bod am adael - efallai na fydd data'n cael ei gadw.
+OnBeforeUnloadStayButton=Aros ar y Dudalen
+OnBeforeUnloadLeaveButton=Gadael y Dudalen
+EmptyGetElementByIdParam=Cafodd llinyn gwag ei drosglwyddo i getElementById().
+SpeculationFailed=Ysgrifennwyd y goeden anghytbwys gan ddefnyddio document.write() gan achosi i ddata o'r rhwydwaith gael ei ail ddidoli. Am fwy o wybodaeth https://developer.mozilla.org/en/Optimizing_Your_Pages_for_Speculative_Parsing
+DocumentWriteIgnored=Anwybyddwyd galwad i document.write() o sgript allanoll lwythwyd yn anghytamseredig.
+# LOCALIZATION NOTE (EditorFileDropFailed): Do not translate contenteditable, %S is the error message explaining why the drop failed.
+EditorFileDropFailed=Methwyd gollwng ffeil i elfen cynnwys golygadwy: %S.
+FormValidationTextTooLong=Cyfyngwch y testun i %S nod neu lai (rydych yn defnyddio %S nod ar hyn o bryd).
+FormValidationTextTooShort=Defnyddiwch o leiaf %S nod (rydych yn defnyddio %S nod ar hyn o bryd).
+FormValidationValueMissing=Llanwch y maes yma.
+FormValidationCheckboxMissing=Ticiwch y blwch os ydych am barhau.
+FormValidationRadioMissing=Dewiswch un o'r tri dewis.
+FormValidationFileMissing=Dewiswch ffeil.
+FormValidationSelectMissing=Dewiswch eitem yn y rhestr.
+FormValidationInvalidEmail=Rhowch gyfeiriad e-bost.
+FormValidationInvalidURL=Rhowch URL.
+FormValidationInvalidDate =Rhowch ddyddiad dilys.
+FormValidationPatternMismatch=Cydweddwch y fformat.
+# LOCALIZATION NOTE (FormValidationPatternMismatchWithTitle): %S is the (possibly truncated) title attribute value.
+FormValidationPatternMismatchWithTitle=Cydweddwch y fformat: %S.
+# LOCALIZATION NOTE (FormValidationNumberRangeOverflow): %S is a number.
+FormValidationNumberRangeOverflow=Dewiswch werth sy'n llai na %S.
+# LOCALIZATION NOTE (FormValidationDateTimeRangeOverflow): %S is a date or a time.
+FormValidationDateTimeRangeOverflow=Dewiswch werth sydd ddim hwyrach na %S.
+# LOCALIZATION NOTE (FormValidationNumberRangeUnderflow): %S is a number.
+FormValidationNumberRangeUnderflow=Dewiswch werth sydd ddim llai na %S.
+# LOCALIZATION NOTE (FormValidationDateTimeRangeUnderflow): %S is a date or a time.
+FormValidationDateTimeRangeUnderflow=Dewiswch werth sydd ddim cynt na %S.
+# LOCALIZATION NOTE (FormValidationStepMismatch): both %S can be a number, a date or a time.
+FormValidationStepMismatch=Dewiswch werth dilys. Y gwerthoedd dilys nesaf yw %S a %S,.
+# LOCALIZATION NOTE (FormValidationStepMismatchOneValue): %S can be a number, a date or a time. This is called instead of FormValidationStepMismatch when the second value is the same as the first.
+FormValidationStepMismatchOneValue=Dewiswch werth dilys. Y gwerthoedd dilys agosaf yw %S.
+# LOCALIZATION NOTE (FormValidationTimeReversedRangeUnderflowAndOverflow): %1$S,%2$S are time.
+FormValidationTimeReversedRangeUnderflowAndOverflow=Dewiswch werth rhwng %1$S a %2$S.
+FormValidationBadInputNumber=Rhowch rif.
+FullscreenDeniedDisabled=Gwrthodwyd cais am sgrin lawn oherwydd mae'r API Sgrin Llawn wedi ei analluogi yn newisiadau'r defnyddiwr.
+FullscreenDeniedFocusedPlugin=Gwrthodwyd cais am sgrin lawn gan fod yr ategyn ffenestr wedi ei ffocysu.
+FullscreenDeniedHidden=Gwrthodwyd y cais am y sgrin lawn am nad yw'r ddogfen bellach yn weladwy.
+FullscreenDeniedHTMLDialog=Gwrthodwyd y cais am sgrin lawn oherwydd mae'r elfen yn elfen <dialog>.
+FullscreenDeniedContainerNotAllowed=Gwrthodwyd cais am sgrin lawn gan nad yw o leiaf un o'r ddogfennau yn cynnwys elfennau nad yw'n iframes nac yn cynnwys priodwedd "allowfullscreen".
+FullscreenDeniedNotInputDriven=Gwrthodwyd cais am sgrin lawn gan nad oedd Element.requestFullscreen() wedi ei alw o fewn triniwr digwyddiad rhedeg yn fyr gynhyrchwyd gan y defnyddiwr.
+FullscreenDeniedMouseEventOnlyLeftBtn=Gwrthodwyd cais am sgrin lawn gan fod Element.requestFullscreen() wedi ei alw o fewn triniwr digwyddiad llygoden nad oedd wedi ei gychwyn gan fotwm chwith y llygoden.
+FullscreenDeniedNotHTMLSVGOrMathML=Gwrthodwyd cais am sgrin lawn gan nad yw'r elfen oedd yn gofyn amdano yn <svg>, <math>, neu elfen HTML.
+FullscreenDeniedNotInDocument=Gwrthodwyd cais am sgrin lawn gan nad yw'r elfen oedd yn gofyn amdano bellach o fewn ei ddogfen.
+FullscreenDeniedMovedDocument=Gwrthodwyd y cais am sgrin lawn oherwydd roedd mae'r elfen oedd yn gofyn wedi symud dogfen.
+FullscreenDeniedLostWindow=Gwrthodwyd y cais am sgrin lawn oherwydd nad oes gennym ffenestr.
+FullscreenDeniedSubDocFullscreen=Gwrthodwyd y cais am sgrin lawn oherwydd mae'r isddogfen y ddogfen sy'n gofyn am sgrin lawn eisoes yn sgrin lawn.
+FullscreenDeniedNotDescendant=Gwrthodwyd cais am sgrin lawn oherwydd nad yw'r elfen sy'n gofyn yn ddisgynnydd o'r elfen sgrin lawn gyfredol.
+FullscreenDeniedNotFocusedTab=Gwrthodwyd cais am sgrin lawn oherwydd nad oedd yr elfen o fewn y tab canolbwyntio cyfredol.
+FullscreenDeniedFeaturePolicy=Gwrthodwyd cais am sgrin lawn oherwydd cyfarwyddid FeaturePolicy.
+FullscreenExitWindowFocus=Wedi gadael y sgrin lawn oherwydd bod ffenestr wedi'i ffocysu.
+RemovedFullscreenElement=Gadawyd y sgrin llawn gan i'r elfen sgrin llawn gael ei dynnu o'r ddogfen.
+FocusedWindowedPluginWhileFullscreen=Gadawyd y sgrin llawn gan fod yr ategyn ffenestrog wedi ei ganolbwyntio.
+PointerLockDeniedDisabled=Gwrthodwyd cais am sgrin lawn oherwydd mae'r API Clo Pwyntydd wedi ei analluogi yn newisiadau'r defnyddiwr.
+PointerLockDeniedInUse=Gwrthodwyd cais am glo pwyntydd oherwydd bod y pwyntydd yn cael ei reoli gan ddogfen wahanol.
+PointerLockDeniedNotInDocument=Gwrthodwyd cais am glo pwyntydd oherwydd nad yw'r elfen sy'n gofyn mewn dogfen.
+PointerLockDeniedSandboxed=Gwrthodwyd cais am gol pwyntydd gan fod API Clo Pwyntydd wedi ei gyfyngu drwy flwch tywod.
+PointerLockDeniedHidden=Gwrthodwyd y cais am y clo sgrin am nad yw'r ddogfen bellach yn weladwy.
+PointerLockDeniedNotFocused=Gwrthodwyd cais am glo pwyntydd oherwydd nad yw'r ddogfen wedi ei ffocysu.
+PointerLockDeniedMovedDocument=Gwrthodwyd y cais am glo pwyntydd oherwydd roedd yr elfen oedd yn gofyn wedi symud dogfen.
+PointerLockDeniedNotInputDriven=Gwrthodwyd y cais am glo pwyntydd oherwydd nad oedd Element.requestPointerLock() wedi ei alw o fewn triniwr digwyddiad byr cynhyrchwyd gan ddefnyddiwr, ac nad yw'r ddogfen yn sgrin llawn.
+PointerLockDeniedFailedToLock=Gwrthodwyd cais am glo pwyntydd oherwydd methiant y porwr i gloi'r pwyntydd.
+HTMLSyncXHRWarning=Nid yw didoli HTML yn XMLHttpRequest yn cael ei gynnal yn y modd cydamserol.
+# LOCALIZATION NOTE: %S is the name of the header in question
+ForbiddenHeaderWarning=Cafodd ymgais i osod pennyn gwaharddedig ei wrthod: %S
+ResponseTypeSyncXHRWarning=Nid yw defnydd o briodwedd responseType XMLHttpRequest yn cael ei gynnal bellach yn y modd cydamserol o fewn cyd-destun ffenestr.
+TimeoutSyncXHRWarning=Nid yw'r defnydd o briodwedd allan o amser XMLHttpRequest yn cael ei gynnal yn y modd cydweddu o fewn cyd-destun ffenestr.
+# LOCALIZATION NOTE: Do not translate navigator.sendBeacon, unload, pagehide, or XMLHttpRequest.
+UseSendBeaconDuringUnloadAndPagehideWarning=Mae'r defnydd o navigator.sendBeacon yn lle XMLHttpRequest cydweddus wrth llwytho a cudd-dalen yn gwella profiad y defnyddiwr.
+JSONCharsetWarning=Gwnaed cais i ddatgan amgodiad an UTF-8 ar gyfer JSON wedi ei adfer gan ddefnyddio XMLHttpRequest. Dim ond UTF-8 sy'n cael ei gynnal i dadgodio JSON.
+# LOCALIZATION NOTE: Do not translate decodeAudioData.
+MediaDecodeAudioDataUnknownContentType=Mae'r byffer pasiwyd i decodeAudioData yn cynnwys math anhysbys o gynnwys.
+# LOCALIZATION NOTE: Do not translate decodeAudioData.
+MediaDecodeAudioDataUnknownError=Digwyddodd gwall anhysbys wrth brosesu decodeAudioData.
+# LOCALIZATION NOTE: Do not translate decodeAudioData.
+MediaDecodeAudioDataInvalidContent=Mae'r byffer pasiwyd i decodeAudioData yn cynnwys deunydd annilys nad oes modd ei ddadgodio'n llwyddiannus.
+# LOCALIZATION NOTE: Do not translate decodeAudioData.
+MediaDecodeAudioDataNoAudio=Nid yw'r byffer basiwyd i decodeAudioData yn cynnwys unrhyw sain.
+# LOCALIZATION NOTE: Do not translate HTMLMediaElement and createMediaElementSource.
+MediaElementAudioSourceNodeCrossOrigin=Mae gan yr HTMLMediaElement basiwyd i createMediaElementSource adnodd croesdarddiad, bydd y nod yn allbynnu tawelwch.
+# LOCALIZATION NOTE: Do not translate MediaStream and createMediaStreamSource.
+MediaStreamAudioSourceNodeCrossOrigin=Mae gan y MediaStream basiwyd i createMediaElementSource adnodd croesdarddiad, bydd y nod yn allbynnu tawelwch.
+# LOCALIZATION NOTE : Do not translate MediaStreamTrack and createMediaStreamTrackSource.
+MediaStreamTrackAudioSourceNodeCrossOrigin=Mae'r MediaStream basiwyd i createMediaElementSource yn adnodd croesdarddiad, bydd y nod yn allbynnu tawelwch.
+# LOCALIZATION NOTE: Do not translate HTMLMediaElement and MediaStream.
+MediaElementAudioCaptureOfMediaStreamError=Mae'r HTMLMediaElement gafodd ei gipio'n chwarae MediaStream. Nid yw gosod statws maint sain na tewi'n cael ei gynnal ar hyn o bryd.
+# LOCALIZATION NOTE: Do not translate HTMLMediaElement and MediaStream.
+MediaElementStreamCaptureCycle=Daw'r MediaStream a neilltuwyd i srcObject o gipio'r HTMLMediaElement hwn, gan ffurfio cylch, anwybyddu aseiniad.
+MediaLoadExhaustedCandidates=Methodd llwytho pob adnodd ymgeisydd. Oedwyd llwytho cyfrwng.
+MediaLoadSourceMissingSrc=Nid oes gan elfen <source> briodwedd “src”. Methodd llwytho'r adnoddau cyfrwng.
+MediaStreamAudioSourceNodeDifferentRate=Nid yw cysylltu AudioNodes o AudioContexts gyda graddfa samplo gwahanol yn cael ei gynnal.
+# LOCALIZATION NOTE: %1$S is the Http error code the server returned (e.g. 404, 500, etc), %2$S is the URL of the media resource which failed to load.
+MediaLoadHttpError=Methodd llwytho HTTP gyda statws %1$S. Methodd llwytho adnoddau %2$S.
+# LOCALIZATION NOTE: %S is the URL of the media resource which failed to load.
+MediaLoadInvalidURI=URI annilys. Methodd llwytho adnoddau %S.
+# LOCALIZATION NOTE: %1$S is the media resource's format/codec type (basically equivalent to the file type, e.g. MP4,AVI,WMV,MOV etc), %2$S is the URL of the media resource which failed to load.
+MediaLoadUnsupportedTypeAttribute=Nid yw priodwedd “type” o “%1$S” ipenodol yn cael eu cynnal. Methodd llwytho cyfrwng %2$S.
+MediaLoadUnsupportedTypeAttributeLoadingNextChild=Nid yw priodoledd “type” penodedig o “%1$S” yn cael ei gynnal. Methodd llwytho adnoddau cyfryngau %2$S. Wrthi'n ceisio llwytho o'r elfen <source> nesaf.
+# LOCALIZATION NOTE: %1$S is the MIME type HTTP header being sent by the web server, %2$S is the URL of the media resource which failed to load.
+MediaLoadUnsupportedMimeType=Nid yw “Content-Type” o “%1$S” HTTP yn cael eu cynnal. Methodd llwytho adnoddau %2$S.
+# LOCALIZATION NOTE: %S is the URL of the media resource which failed to load because of error in decoding.
+MediaLoadDecodeError=Nid oedd modd dadgodio adnodd cyfrwng %S.
+MediaWidevineNoWMF=Ceisio chwarae Widevine heb Windows Media Foundation. Gw. https://support.mozilla.org/kb/fix-video-audio-problems-firefox-windows
+# LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
+MediaWMFNeeded=I chwarae fformatau fideo %S, mae angen gosod meddalwedd ychwanegol gan Microsoft, gw. https://support.mozilla.org/kb/fix-video-audio-problems-firefox-windows
+# LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
+MediaPlatformDecoderNotFound=Nid oes modd chwarae'r fideo ar y dudalen hon. Efallai nad oes gan eich system y codecs fideo angenrheidiol ar gyfer: %S
+MediaUnsupportedLibavcodec=Nid oes modd chwarae'r fideo ar y dudalen hon. Mae gan eich system fersiwn o libavcodec sydd ddim yn cael ei gynnal
+# LOCALIZATION NOTE: %1$S is the URL of the media resource, %2$S is technical information (in English)
+MediaDecodeError=Nid oedd modd dadgodio adnodd cyfrwng%1$S, gwall: %2$S
+# LOCALIZATION NOTE: %1$S is the URL of the media resource, %2$S is technical information (in English)
+MediaDecodeWarning=Nid oedd modd dadgodio adnodd cyfrwng%1$S, ond gyda gwall: %2$S
+# LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
+MediaCannotPlayNoDecoders=Nid oes modd chwarae'r cyfrwng. Nid oes datgodwyr ar gyfer y fformatau hyn: %S
+# LOCALIZATION NOTE: %S is a comma-separated list of codecs (e.g. 'video/mp4, video/webm')
+MediaNoDecoders=Dim datgodwyr angenrheidiol ar gyfer rhai o'r fformatau hyn: %S
+MediaCannotInitializePulseAudio=Methu defnyddio PulseAudio
+# LOCALIZATION NOTE: Do not translate "MediaRecorder".
+MediaRecorderMultiTracksNotSupported=Nid yw MediaRecorder yn cynnal recordio traciau lluosog o'r un math ar hyn o bryd.
+# LOCALIZATION NOTE: %S is the URL of the web page which is not served on HTTPS and thus is not encrypted and considered insecure.
+MediaEMEInsecureContextDeprecatedWarning=Mae defnyddio Encrypted Media Extensions yn %S ar gyd-destun anniogel (nid HTTPS) yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir. Dylech ystyried newid i wraidd diogel fel HTTPS.
+# LOCALIZATION NOTE: %S is the URL of the web page which is calling web APIs without passing data (either an audioCapabilities or a videoCapabilities) that will soon be required. See https://bugzilla.mozilla.org/show_bug.cgi?id=1368583#c21 for explanation of this string.
+MediaEMENoCapabilitiesDeprecatedWarning=Mae galw navigator.requestMediaKeySystemAccess() (yn %S) heb basio ymgeisydd MediaKeySystemConfiguration yn cynnwys audioCapabilities neu videoCapabilities wedi ei anghymeradwyo ac ni fydd yn cael ei gynnal cyn bo hir.
+# LOCALIZATION NOTE: %S is the URL of the web page which is calling web APIs without passing data (a "codecs" string in the "contentType") that will soon be required. See https://bugzilla.mozilla.org/show_bug.cgi?id=1368583#c21 for explanation of this string.
+MediaEMENoCodecsDeprecatedWarning=Mae galw navigator.requestMediaKeySystemAccess() (yn %S) pasio ymgeisydd MediaKeySystemConfiguration yn cynnwys audioCapabilities neu videoCapabilities heb contentType gyda llinyn “codecs” wedi ei anghymeradwyo ac ni fydd yn cael ei gynnal cyn bo hir.
+# LOCALIZATION NOTE: Do not translate "Mutation Event" and "MutationObserver"
+MutationEventWarning=Mae'r defnydd o Ddigwyddiadau Mutadiad yn anghymeradwy. Defnyddiwch MutationObserveryn lle hynny.
+BlockAutoplayError=Mae awtochwarae ddim ond yn cael ei ganiatáu pan mae wedi ei gymeradwyo gan y defnyddiwr, y wefan wedi ei agor gan y defnyddiwr neu'r cyfrwng wedi ei dewi.
+BlockAutoplayWebAudioStartError=Gwaharddwyd AudioContext rhag cychwyn yn awtomatig. Rhaid ei greu neu ei ailddechrau ar ôl ystum defnyddiwr ar y dudalen.
+# LOCALIZATION NOTE: Do not translate "Components"
+ComponentsWarning=Mae'r gwrthrych Cydran yn anghymarus. Bydd yn cael ei dynnu cyn bo hir.
+PluginHangUITitle=Rhybudd: Ategyn anymatebol
+PluginHangUIMessage=Gall fod %S ar y dudalen hon yn brysur, neu gall ei fod wedi peidio ymateb. Gallwch atal y sgript nawr, neu barhau i weld os fydd y sgript yn cwblhau.
+PluginHangUIWaitButton=Ymlaen
+PluginHangUIStopButton=Atal yr ategyn
+# LOCALIZATION NOTE: Do not translate "NodeIterator" or "detach()".
+NodeIteratorDetachWarning=Nid yw galw detach() ar NodeIterator yn creu effaith bellach.
+# LOCALIZATION NOTE: Do not translate "LenientThis" and "this"
+LenientThisWarning=Anwybyddu get neu set priodoledd sy'n cynnwys [LenientThis] oherwydd bod y gwrthrych “this” yn anghywir.
+# LOCALIZATION NOTE: Do not translate "captureEvents()" or "addEventListener()"
+UseOfCaptureEventsWarning=Mae'r defnydd o captureEvents() yn anghymeradwy. I ddiweddaru eich cod defnyddiwch y dull DOM 2 addEventListener(). Am gymorth pellach gw. http://developer.mozilla.org/en/docs/DOM:element.addEventListener
+# LOCALIZATION NOTE: Do not translate "releaseEvents()" or "removeEventListener()"
+UseOfReleaseEventsWarning=Mae'r defnydd o releaseEvents() yn anghymeradwy. I ddiweddaru eich cod defnyddiwch y dull DOM 2 removeEventListener(). Am gymorth pellach gw. http://developer.mozilla.org/en/docs/DOM:element.removeEventListener
+# LOCALIZATION NOTE: Do not translate "XMLHttpRequest"
+SyncXMLHttpRequestWarning=Mae XMLHttpRequest cydamseredig ar y prif edafedd yn anghydnaws oherwydd ei effeithiau negyddol i brofiad y defnyddiwr. Am ragor o gymorth gweler http://xhr.spec.whatwg.org/
+# LOCALIZATION NOTE: Do not translate "window.controllers/Controllers"
+Window_Cc_ontrollersWarning=Mae window.controllers/Controllers yn anghymeradwy. Peidiwch a'i ddefnyddio ar gyfer canfod UA.
+ImportXULIntoContentWarning=Mae mewnforio nodau XUL i ddogfen cynnwys yn anghymeradwy. Bydd y swyddogaeth yma'n cael ei dynnu'n fuan.
+# LOCALIZATION NOTE: Do not translate "IndexedDB".
+IndexedDBTransactionAbortNavigation=Mae'r trosglwyddiad IndexedDB oedd heb ei gwblhau wedi ei atal oherwydd llywio tudalen.
+# LOCALIZATION NOTE: Do not translate Will-change, %1$S,%2$S are numbers.
+IgnoringWillChangeOverBudgetWarning=Mae'r defnydd o gof will-change yn rhy uchel. Amcangyfrifwch derfyn arwynebedd y ddogfen wedi ei luosogi gyda %1$S (%2$S px). Bydd pob enghraifft o will-change sydd dros yr amcan yn cael eu hanwybyddu.
+# LOCALIZATION NOTE: Do not translate "Worker".
+HittingMaxWorkersPerDomain2=Nid oedd modd cychwyn ServiceWorker yn syth gan fod dogfennau eraill o'r un man eisoes yn defnyddio'r uchafswm nifer o weithwyr. Mae'r ServiceWorker nawr mewn ciw a bydd yn cael ei gychwyn wedi i weithwyr eraill orffen.
+# LOCALIZATION NOTE: Do not translate "Application Cache API", "AppCache" and "ServiceWorker".
+AppCacheWarning=Mae Application Cache API (AppCache) yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir.  Ystyriwch ddefnyddio Service Worker ar gyfer cefnogaeth all-lein.
+# LOCALIZATION NOTE: Do not translate "Worker".
+EmptyWorkerSourceWarning=Yn ceisio creu Gweithiwr o ffynhonnell wag. Mae hyn ar gam, debyg.
+WebrtcDeprecatedPrefixWarning=Mae WebRTC sy'n rhyngweithio gyda'r rhagosodiad "moz" (mozRTCPeerConnection, mozRTCSessionDescription, mozRTCIceCandidate) nawr yn anghymeradwy.
+NavigatorGetUserMediaWarning=Mae navigator.mediaDevices.getUserMedia wedi cymryd lle navigator.mozGetUserMedia
+# LOCALIZATION NOTE: Do not translate "RTCPeerConnection", "getLocalStreams", "getRemoteStreams", "getSenders" or "getReceivers".
+RTCPeerConnectionGetStreamsWarning=Mae RTCPeerConnection.getLocalStreams/getRemoteStreams yn anghymeradwy. Defnyddiwch RTCPeerConnection.getSenders/getReceivers yn lle hynny.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker". %S is a URL.
+InterceptionFailedWithURL=Methwyd llwytho ‘%S’. Mae Service Worker wedi rhyngdorri’r cais ac wedi canfod gwall annisgwyl.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "cors", "Response", "same-origin" or "Request". %1$S is a URL, %2$S is a URL.
+CorsResponseForSameOriginRequest=Wedi methu llwytho ‘%1$S’ drwy ymateb ‘%2$S’. Nid oes modd i Weithiwr Gwasanaeth syntheseiddio cors Response am Request o'r un tarddiad.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "FetchEvent.respondWith()", "FetchEvent", "no-cors", "opaque", "Response", or "RequestMode". %1$S is a URL. %2$S is a RequestMode value.
+BadOpaqueInterceptionRequestModeWithURL=Methwyd llwytho ‘%1$S’. Pasiodd ServiceWorker Response didraidd i FetchEvent.respondWith() tra'n trin‘%2$S’ FetchEvent. Mae gwrthrychau Opaque Response yn ddilys dim ond pan fo'r RequestMode yn ‘no-cors’.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "Error", "Response", "FetchEvent.respondWith()", or "fetch()". %S is a URL.
+InterceptedErrorResponseWithURL=Methwyd llwytho ‘%S’. Pasiodd ServiceWorker Error Response i FetchEvent.respondWith(). Fel arfer mae hyn yn meddwl fod y Service Worker wedi cyflawni galwad fetch() annilys.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "Response", "FetchEvent.respondWith()", or "Response.clone()". %S is a URL.
+InterceptedUsedResponseWithURL=Methwyd llwytho ‘%S’. Pasiodd ServiceWorker hen ymateb Response i FetchEvent.respondWith(). Gall corff y Response gael ei ddarllen unwaith yn unig. Defnyddiwch Response.clone() i gael mynediad i'r corff mwy nag unwaith.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "opaqueredirect", "Response", "FetchEvent.respondWith()", or "FetchEvent". %s is a URL.
+BadOpaqueRedirectInterceptionWithURL=Methwyd llwytho ‘%S’. Pasiodd ServiceWorker opaqueredirect Response t i FetchEvent.respondWith() tra nad oedd FetchEvent.request yn gais llywio.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "Response", "FetchEvent.respondWith()", "RedirectMode" or "follow". %S is a URL.
+BadRedirectModeInterceptionWithURL=Methwyd llwytho ‘%S’. Pasiodd ServiceWorker ailgyfeiriwyd Response to FetchEvent.respondWith() tra nad yw RedirectMode yn ‘follow’.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker" or "FetchEvent.preventDefault()". %S is a URL.
+InterceptionCanceledWithURL=Methwyd llwytho ‘%S’. Diddymodd y ServiceWorker y llwyth drwy alw FetchEvent.preventDefault().
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "promise", or "FetchEvent.respondWith()". %1$S is a URL. %2$S is an error string.
+InterceptionRejectedResponseWithURL=Methwyd llwytho ‘%1$S’. Mae'r ServiceWorker wedi pasio addewid i FetchEvent.respondWith() a wrthodwyd gyda '%2$S'.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "promise", "FetchEvent.respondWith()", or "Response". %1$S is a URL. %2$S is an error string.
+InterceptedNonResponseWithURL=Methwyd llwytho ‘%1$S’. Mae'r ServiceWorker wedi pasio addewid i FetchEvent.respondWith() a ddatryswyd gyda gwrth non-Response ‘%2$S’.
+# LOCALIZATION NOTE: Do not translate "mozImageSmoothingEnabled", or "imageSmoothingEnabled"
+PrefixedImageSmoothingEnabledWarning=Mae'r defnydd o mozimagesmoothingenabled yn waharddedig. Defnyddiwch delwedd y briodwedd anrhagddodiad imagesmoothingenabled yn lle hynny.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker", "Service-Worker-Allowed" or "HTTP". %1$S and %2$S are URLs.
+ServiceWorkerScopePathMismatch=Methu cofrestru ServiceWorker: Nid yw'r llwybr o'r ystod ddarparwyd ‘%1$S’ yr un a'r ystod mwyaf sy'n cael ei ganiatáu ‘%2$S’. Addaswch yr ystod, symud sgript y Service Worker, neu ddefnyddio'r pennyn Service-Worker-Allowed HTTP i ganiatáu'r ystod.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker". %1$S is a URL representing the scope of the ServiceWorker, %2$S is a stringified numeric HTTP status code like "404" and %3$S is a URL.
+ServiceWorkerRegisterNetworkError=Methwyd cofrestru/diweddaru ServiceWorker ar gyfer sgôp ‘%1$S’: Methodd y lwyth gyda statws %2$S sgript ‘%3$S’.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker". %1$S is a URL representing the scope of the ServiceWorker, %2$S is a MIME Media Type like "text/plain" and %3$S is a URL.
+ServiceWorkerRegisterMimeTypeError2=Wedi methu â chofrestru /update ServiceWorker ar gyfer cwmpas ‘%1$S’: Bad Content-Type of ‘%2$S’ a dderbyniwyd ar gyfer sgript '%3$S'. Rhaid bod yn fath MIME JavaScript.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker". %S is a URL representing the scope of the ServiceWorker.
+ServiceWorkerRegisterStorageError=Wedi methu i gofrestr/diweddaru ServiceWorker ar gyfer cwmpas '%S': Cyfyngir ar fynediad storio mewn cyd-destun hwn oherwydd gosodiadau defnyddiwr neu modd pori preifat.
+ServiceWorkerGetRegistrationStorageError=Wedi methu cael cofrestriad(au) gweithwyr gwasanaeth: Mae mynediad i storfa yn gyfyngedig yn y cyd-destun hwn oherwydd gosodiadau defnyddiwr neu'r modd pori preifat.
+ServiceWorkerGetClientStorageError=Wedi methu cael cleient(iaid) gweithwyr gwasanaeth: Mae mynediad i storfa yn gyfyngedig yn y cyd-destun hwn oherwydd gosodiadau defnyddiwr neu'r modd pori preifat.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker" and "postMessage". %S is a URL representing the scope of the ServiceWorker.
+ServiceWorkerPostMessageStorageError=Me'r Gweithiwr Gwasanaeth ar gyfer sgop ‘%S’ wedi methu gweithredu ‘postMessage‘ oherwydd fod mynediad i storfa yn gyfyngedig yn y cyd-destun hwn oherwydd gosodiadau defnyddiwr neu'r modd pori preifat.
+# LOCALIZATION NOTE: Do not translate "ServiceWorker". %1$S is a URL representing the scope of the ServiceWorker.
+ServiceWorkerGraceTimeoutTermination=Terfynnu ServiceWorker ar gyfer sgôp ‘%1$S’ gyda waitUntil/respondWith yn aros gan addo oherwydd oedi amser allan.
+# LOCALIZATION NOTE (ServiceWorkerNoFetchHandler): Do not translate "Fetch".
+ServiceWorkerNoFetchHandler=Rhaid i estynwyr trinwyr digwyddiad gael eu ychwanegu yn ystod gwerthuso cychwynnol sgript y gweithiwr.
+ExecCommandCutCopyDeniedNotInputDriven=Gwrthodwyd document.execCommand(‘cut’/‘copy’) gan nad yw wedi cael ei alw o fewn triniwr digwyddiad rhedeg byr cynnyrch defnyddiwr.
+ManifestShouldBeObject=Rhaid i'r maniffest fod yn wrthrych.
+ManifestScopeURLInvalid=Mae'r URL ystod yn annilys.
+ManifestScopeNotSameOrigin=Rhaid i'r URL ystod fod o'r un ffynhonnell â'r ddogfen.
+ManifestStartURLOutsideScope=Mae'r URL cychwyn y tu allan i'r ystod, felly mae'r ystod yn annilys.
+ManifestStartURLInvalid=Mae'r URL cychwyn yn annilys.
+ManifestStartURLShouldBeSameOrigin=Rhaid i'r URL cychwynnol fod o'r un ffynhonnell â'r ddogfen.
+# LOCALIZATION NOTE: %1$S is the name of the object whose property is invalid. %2$S is the name of the invalid property. %3$S is the expected type of the property value. E.g. "Expected the manifest's start_url member to be a string."
+ManifestInvalidType=Disgwyliwyd i'r aelod %1$S %2$S fod yn %3$S.
+# LOCALIZATION NOTE: %1$S is the name of the property whose value is invalid. %2$S is the (invalid) value of the property. E.g. "theme_color: 42 is not a valid CSS color."
+ManifestInvalidCSSColor=%1$S: Nid yw %2$S yn lliw CSS dilys.
+# LOCALIZATION NOTE: %1$S is the name of the property whose value is invalid. %2$S is the (invalid) value of the property. E.g. "lang: 42 is not a valid language code."
+ManifestLangIsInvalid=%1$S: Nid yw %2$S yn god iaith dilys.
+# LOCALIZATION NOTE: %1$S is the name of the parent property whose value is invalid (e.g., "icons"). %2$S is the index of the image object that is invalid (from 0). %3$S is the name of actual member that is invalid. %4$S is the invalid value. E.g. "icons item at index 2 is invalid. The src member is an invalid URL http://:Invalid"
+ManifestImageURLIsInvalid=Mae eitem %1$S ar fynegai %2$S yn annilys. Mae'r aelod %3$S yn URL annilys %4$S
+# LOCALIZATION NOTE: %1$S is the name of the parent property that that contains the unusable image object (e.g., "icons"). %2$S is the index of the image object that is unusable (from 0). E.g. "icons item at index 2 lacks a usable purpose. It will be ignored."
+ManifestImageUnusable=Nid oes gan eitem %1$S ar fynegai %2$S bwrpas defnyddiol. Bydd yn cael ei anwybyddu.
+# LOCALIZATION NOTE: %1$S is the name of the parent property that contains the unsupported value (e.g., "icons"). %2$S is the index of the image object that has the unsupported value (from 0). %3$S are the unknown purposes. E.g. "icons item at index 2 includes unsupported purpose(s): a b."
+ManifestImageUnsupportedPurposes=Mae gan eitem %1$S ar fynegai %2$S bwrpas(au) heb eu cynnal: %3$S.
+# LOCALIZATION NOTE: %1$S is the name of the parent property that has a repeated purpose (e.g., "icons"). %2$S is the index of the image object that has the repeated purpose (from 0). %3$S is the repeated purposes. E.g. "icons item at index 2 includes repeated purpose(s): a b."
+ManifestImageRepeatedPurposes=Mae gan eitem %1$S ar fynegai %2$S bwrpas(au) sy'n cynnwys eu hailadrodd: %3$S.
+PatternAttributeCompileFailure=Methu gwirio <input pattern='%S'> gan nad yw'r patrwm yn regexp dilys: %S
+# LOCALIZATION NOTE: Do not translate "postMessage" or DOMWindow. %S values are origins, like https://domain.com:port
+TargetPrincipalDoesNotMatch=Methu gweithredu ‘postMessage’ ar ‘DOMWindow’: Nid yw'r ffynhonnell targed ddarparwyd (‘%S’) yn cyd fynd â ffynhonnell ffenestr y derbynnydd (‘%S’).
+# LOCALIZATION NOTE: Do not translate 'YouTube'. %S values are origins, like https://domain.com:port
+RewriteYouTubeEmbed=Ailysgrifennu mewnblaniad Flash YouTube (%S) hen ffasiwn i fewnblaniad iframe (%S). Diweddarwch y dudalen i ddefnyddio iframe yn lle embed/object, os yn bosib.
+# LOCALIZATION NOTE: Do not translate 'YouTube'. %S values are origins, like https://domain.com:port
+RewriteYouTubeEmbedPathParams=Ailysgrifennu mewnblaniad Flash YouTube (%S) hen ffasiwn i mewnblaniad iframe (%S). Roedd yr ymholiad yn annilys ac mae wedi ei dynnu o'r URL. Diweddarwch y dudalen i ddefnyddio iframe yn lle embed/object, os yn bosib.
+# LOCALIZATION NOTE: This error is reported when the "Encryption" header for an
+# incoming push message is missing or invalid. Do not translate "ServiceWorker",
+# "Encryption", and "salt". %1$S is the ServiceWorker scope URL.
+PushMessageBadEncryptionHeader=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘Encryption’ gynnwys baramedr unigryw ‘salt‘ ar gyfer pob neges. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-3.1 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when the "Crypto-Key" header for an
+# incoming push message is missing or invalid. Do not translate "ServiceWorker",
+# "Crypto-Key", and "dh". %1$S is the ServiceWorker scope URL.
+PushMessageBadCryptoKeyHeader=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘Crypto-Key’ gynnwys baramedr ‘dh‘ sy'n cynnwys allwedd gyhoeddus gweinydd yr ap. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-4 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt because the deprecated
+# "Encryption-Key" header for an incoming push message is missing or invalid.
+# Do not translate "ServiceWorker", "Encryption-Key", "dh", "Crypto-Key", and
+# "Content-Encoding: aesgcm". %1$S is the ServiceWorker scope URL.
+PushMessageBadEncryptionKeyHeader=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘Encryption-Key’ gynnwys baramedr ‘dh‘. Mae'r pennyn yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir. Defnyddiwch ‘Crypto-Key‘ gyda‘Content-Encoding: aesgcm‘ yn lle hynny. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-4 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt
+# because the "Content-Encoding" header is missing or contains an
+# unsupported encoding. Do not translate "ServiceWorker", "Content-Encoding",
+# "aesgcm", and "aesgcm128". %1$S is the ServiceWorker scope URL.
+PushMessageBadEncodingHeader=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘Content-Encoding’ fod ‘aesgcm‘. Mae ‘aesgcm128‘ yn cael ei ganiatáu ond yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-2 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt
+# because the "dh" parameter is not valid base64url. Do not translate
+# "ServiceWorker", "dh", "Crypto-Key", and "base64url". %1$S is the
+# ServiceWorker scope URL.
+PushMessageBadSenderKey=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘dh’ yn y pennyn ‘Crypto-Key‘ fod yn allwedd gyhoeddus Diffie-Hellman gweinydd yr ap, amgodiad base64url (https://tools.ietf.org/html/rfc7515#appendix-C) ac mewn ffurf “dad-gywasgedig” neu “fras” (65 did cyn amgodio). Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-4 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt
+# because the "salt" parameter is not valid base64url. Do not translate
+# "ServiceWorker", "salt", "Encryption", and "base64url". %1$S is the
+# ServiceWorker scope URL.
+PushMessageBadSalt=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘salt’ yn y pennyn ‘Encryption‘ fod yn amgodiad base64url (https://tools.ietf.org/html/rfc7515#appendix-C) ac o leiaf 16 did cyn amgodio. Gwe https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-3.1 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt
+# because the "rs" parameter is not a number, or is less than the pad size.
+# Do not translate "ServiceWorker", "rs", or "Encryption". %1$S is the
+# ServiceWorker scope URL. %2$S is the minimum value (1 for aesgcm128, 2 for
+# aesgcm).
+PushMessageBadRecordSize=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Rhaid i'r pennyn ‘rs’ fod %2$S and 2^36-31, neu wedi ei hepgor yn llwyr. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-3.1 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when a push message fails to decrypt
+# because an encrypted record is shorter than the pad size, the pad is larger
+# than the record, or any of the padding bytes are non-zero. Do not translate
+# "ServiceWorker". %1$S is the ServiceWorker scope URL. %2$S is the pad size
+# (1 for aesgcm128, 2 for aesgcm).
+PushMessageBadPaddingError=Mae'r ServiceWorker ar gyfer sgôp ‘%1$S’ wedi methu dadgryptio neges gwthio. Nid oedd cofnod o'r neges amgryptiedig wedi ei badio'n gywir. Gw https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-02#section-2 am ragor o wybodaeth.
+# LOCALIZATION NOTE: This error is reported when push message decryption fails
+# and no specific error info is available. Do not translate "ServiceWorker".
+# %1$S is the ServiceWorker scope URL.
+PushMessageBadCryptoError=Mae'r ServiceWorker ar gyfer ystod ‘%1$S’ wedi methu dadgryptio neges gwthio. I dderbyn cymorth gyda amgryptio, gweler https://developer.mozilla.org/docs/Web/API/Push_API/Using_the_Push_API#Encryption
+# LOCALIZATION NOTE: %1$S is the type of a DOM event. 'passive' is a literal parameter from the DOM spec.
+PreventDefaultFromPassiveListenerWarning=Anwybyddu galwad ‘preventDefault()’ ar ddigwyddiad o fath ‘%1$S’ o wrandawr wedi ei gofrestru fel ‘passive’.
+# LOCALIZATION NOTE: 'ImageBitmapRenderingContext.transferImageBitmap' and 'ImageBitmapRenderingContext.transferFromImageBitmap' should not be translated
+ImageBitmapRenderingContext_TransferImageBitmapWarning=Mae ImageBitmapRenderingContext.transferImageBitmap yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir. Defnyddiwch ImageBitmapRenderingContext.transferFromImageBitmap yn lle hynny.
+IIRFilterChannelCountChangeWarning=Gall cyfrif sianel IIRFilterNode greu anawsterau gyda'r sain.
+BiquadFilterChannelCountChangeWarning=Gall cyfrif sianel BiquadFilterNode greu anawsterau gyda'r sain.
+# LOCALIZATION NOTE: Do not translate ".png"
+GenericImageNamePNG=delwedd.png
+GenericFileName=ffeil
+# LOCALIZATION NOTE: Do not translate "Large-Allocation", as it is a literal header name
+LargeAllocationSuccess=Mae'r dudalen wedi ei llwytho mewn proses newydd oherwydd pennyn Large-Allocation.
+# LOCALIZATION NOTE: Do not translate "Large-Allocation", as it is a literal header name. Do not translate GET.
+LargeAllocationNonGetRequest=Anwybyddwyd pennyn Large-Allocation oherwydd y llwyth roedd yn ei gychwyn gan gais nad oedd yn GET.
+# LOCALIZATION NOTE: Do not translate "Large-Allocation", as it is a literal header name. Do not translate `window.opener`.
+LargeAllocationNotOnlyToplevelInTabGroup=Anwybyddwyd pennyn Large-Allocation oherwydd presenoldeb ffenestri sydd â chyfeirnod i'r cyd-destun pori hwn drwy hierarchiaeth ffrâm neu window.opener.
+# LOCALIZATION NOTE: Do not translate "Large-Allocation", as it is a literal header name
+LargeAllocationNonE10S=Anwybyddwyd pennyn Large-Allocation oherwydd nad oedd y ddogfen wedi ei llwytho tu allan i'r broses.
+GeolocationInsecureRequestIsForbidden=Dim ond mewn cyd-destun diogel y mae modd cyflawni cais geoleoliad.
+NotificationsInsecureRequestIsForbidden=Dim ond mewn cyd-destun diogel y mae modd gofyn am ganiatâd Hysbysiad.
+NotificationsCrossOriginIframeRequestIsForbidden=Dim ond mewn dogfen lefel uchaf neu iframe o'r un tarddiad y gofynnir am y caniatâd Hysbysu.
+NotificationsRequireUserGesture=Dim ond o fewn triniwr digwyddiad byr wedi ei gynhyrchu gan y defnyddiwr y kae modd gofyn am ganiatad hysbysu.
+NotificationsRequireUserGestureDeprecationWarning=Nid yw gofyn am ganiatâd Hysbysiad y tu allan i drinwr digwyddiadau sy'n cael ei gynhyrchu gan ddefnyddwyr yn anghymeradwy ac ni fydd yn cael ei gefnogi yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate "Large-Allocation", as it is a literal header name.
+LargeAllocationNonWin32=Bydd y dudalen yn cael ei llwytho i broses newydd oherwydd pennyn Large-Allocation, er hynny mae creu proses Large-Allocation wedi ei anablu ar blatfformau nad ydynt yn rhai Win32.
+# LOCALIZATION NOTE: Do not translate "content", "Window", and "window.top"
+WindowContentUntrustedWarning=Mae priodwedd ‘content’ gwrthrychau Windows yn anghymeradwy. Defnyddiwch ‘window.top’ yn lle hynny.
+# LOCALIZATION NOTE: The first %S is the tag name of the element that starts the loop, the second %S is the element's ID.
+SVGRefLoopWarning=Mae gan SVG <%S> gydag ID “%S” gylch cyfeirinod.
+# LOCALIZATION NOTE: The first %S is the tag name of the element in the chain where the chain was broken, the second %S is the element's ID.
+SVGRefChainLengthExceededWarning=Cafodd gadwyn cyfeirio SVG <%S> sy'n rhy hir ei adael wrth yr elfen gydag ID “%S”.
+# LOCALIZATION NOTE: Do not translate "<script>".
+ScriptSourceEmpty=Mae priodoledd ‘%S’ elfen <script> yn wag.
+# LOCALIZATION NOTE: Do not translate "<script>".
+ScriptSourceInvalidUri=Nid yw priodoledd elfen <script> ‘%S’ yn URI dilys: “%S”
+# LOCALIZATION NOTE: Do not translate "<script>".
+ScriptSourceLoadFailed=Methwyd llwytho <script> o ffynhonnell “%S”.
+ModuleSourceLoadFailed=Methodd llwytho'r modiwl sydd â ffynhonnell “%S”.
+# LOCALIZATION NOTE: Do not translate "<script>".
+ScriptSourceMalformed=Mae ffynhonnell URI <script> wedi ei anffurfio: “%S”.
+ModuleSourceMalformed=Mae ffynhonnell modiwl URI wedi ei anffurfio: “%S”.
+# LOCALIZATION NOTE: Do not translate "<script>".
+ScriptSourceNotAllowed=Nid yw ffynhonnell URI <script> yn cael ei ganiatáu yn y ddogfen hon: “%S”.
+ModuleSourceNotAllowed=Nid oes caniatâd ar gyfer ffynhonnell modiwl URI yn y ddogfen hon: “%S”.
+ModuleResolveFailure=Gwall wrth ddatrys manylebwr modiwl “%S”. Rhaid i fanylebwyr modiwlau cymharol ddechrau gyda “./”, “../” neu “/”.
+# LOCALIZATION NOTE: %1$S is the invalid property value and %2$S is the property name.
+InvalidKeyframePropertyValue=Mae gwerth priodoledd keyframe “%1$S” yn annilys yn ôl y gystrawen ar gyfer “%2$S”.
+# LOCALIZATION NOTE: Do not translate "ReadableStream".
+ReadableStreamReadingFailed=Wedi methu darllen data o ReadableStream: “%S”.
+# LOCALIZATION NOTE: Do not translate "registerProtocolHandler"
+RegisterProtocolHandlerPrivateBrowsingWarning=Methu defnyddio registerProtocolHandler y tu mewn i'r modd pori preifat.
+MotionEventWarning=Mae defnydd o'r synhwyrydd symud yn anghymeradwy.
+OrientationEventWarning=Mae defnydd o'r synhwyrydd cyfeiriad yn anghymeradwy.
+ProximityEventWarning=Mae defnydd o'r synhwyrydd agosrwydd yn anghymeradwy.
+AmbientLightEventWarning=Mae defnydd o'r synhwyrydd golau'r amgylchedd  yn anghymeradwy.
+# LOCALIZATION NOTE: Do not translate "storage", "indexedDB.open" and "navigator.storage.persist()".
+IDBOpenDBOptions_StorageTypeWarning=Mae'r briodoledd ‘storage’ yn y dewisiadau wedi eu pasio i indexedDB.open yn anghymeradwy a bydd yn cael ei dynnu cyn bo hir. I gael storio parhaus defnyddiwch navigator.storage.persist() yn lle hynny.
+UnsupportedEntryTypesIgnored=Anwybyddu entryTypes heb gymorth: %S.
+AllEntryTypesIgnored=Dim entryTypes dilys; atal y cofrestru.
+# LOCALIZATION NOTE: do not localize key=“%S” modifiers=“%S” id=“%S”
+GTK2Conflict2=Nid yw'r digwyddiad allweddol ar gael ar GTK2:: key=“%S” modifiers=“%S” id=“%S”
+WinConflict2=Nid yw'r digwyddiad allweddol ar gael ar rhai cynlluniau bysellfwrdd: key=“%S” modifiers=“%S” id=“%S”
+# LOCALIZATION NOTE: do not trnaslated "document.domain"
+DocumentSetDomainNotAllowedWarning=Nid yw gosod document.domain yn cael ei ganiatáu mewn amgylchedd ynysig traws-darddiad.
+
+#LOCALIZATION NOTE(DeprecatedTestingInterfaceWarning): Do not translate this message. It's just testing only.
+DeprecatedTestingInterfaceWarning=Mae TestingDeprecatedInterface yn rhyngwyneb profi a hwn yw ei neges anghymeradwy profi.
+#LOCALIZATION NOTE(DeprecatedTestingMethodWarning): Do not translate this message. It's just testing only.
+DeprecatedTestingMethodWarning=Mae TestingDeprecatedInterface.deprecatedMethod() yn ddull profi yn unig a hwn yw ei neges anghymeradwy profi.
+#LOCALIZATION NOTE(DeprecatedTestingAttributeWarning): Do not translate this message. It's just testing only.
+DeprecatedTestingAttributeWarning=Mae TestingDeprecatedInterface.deprecatedAttribute yn briodoledd profi yn unig a hwn yw ei neges anghymeradwy profi.
+# LOCALIZATION NOTE (CreateImageBitmapCanvasRenderingContext2DWarning): Do not translate CanvasRenderingContext2D and createImageBitmap.
+CreateImageBitmapCanvasRenderingContext2DWarning=Nid yw defnyddio CanvasRenderingContext2D yn createImageBitmap yn dderbyniol.
+# LOCALIZATION NOTE (MozRequestFullScreenDeprecatedPrefixWarning): Do not translate mozRequestFullScreen.
+MozRequestFullScreenDeprecatedPrefixWarning=Mae mozRequestFullScreen() yn anghymeradwy.
+# LOCALIZATION NOTE (MozfullscreenchangeDeprecatedPrefixWarning): Do not translate onmozfullscreenchange.
+MozfullscreenchangeDeprecatedPrefixWarning=Mae onmozfullscreenchange yn anghymeradwy.
+# LOCALIZATION NOTE (MozfullscreenerrorDeprecatedPrefixWarning): Do not translate onmozfullscreenerror.
+MozfullscreenerrorDeprecatedPrefixWarning=Mae onmozfullscreenerror yn anghymeradwy.
+# LOCALIZATION NOTE(External_AddSearchProviderWarning): Do not translate AddSearchProvider.
+External_AddSearchProviderWarning=Mae AddSearchProvider yn anghymarus.
+# LOCALIZATION NOTE: Do not translate "MouseEvent.mozPressure" and "PointerEvent.pressure".
+MouseEvent_MozPressureWarning=Mae MouseEvent.mozPressure yn anghymeradwy. Defnyddiwch PointerEvent.pressure yn lle hynny.
+# LOCALIZATION NOTE: Do not translate MathML, align, numalign and denomalign.
+MathML_DeprecatedAlignmentAttributesWarning=Mae priodoleddau MathML yn “align”, “numalign” a “denomalign” yn werthoedd anghymeradwy a byddant yn cael eu tynnu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML and bevelled.
+MathML_DeprecatedBevelledAttribute=Mae priodoledd MathML “bevelled” yn anghymeradwy ac efallai bydd yn cael ei ddileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate thin, medium, thick and linethickness.
+MathML_DeprecatedLineThicknessValueWarning=Mae “thin”, “thin” a “thick” yn werthoedd anghymeradwy ar gyfer y priodoledd trwch llinell a byddan nhw'n cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate small, normal, big and mathsize.
+MathML_DeprecatedMathSizeValueWarning=Mae “small”, “normal” a “big” yn werthoedd anghymeradwy ar gyfer y priodoledd mathsize a byddan nhw'n cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate veryverythinmathspace, verythinmathspace,
+# thinmathspace, mediummathspace, thickmathspace, verythickmathspace, veryverythickmathspace and MathML.
+MathML_DeprecatedMathSpaceValueWarning=Mae “veryverythinmathspace”, “verythinmathspace”, “thinmathspace”, “mediummathspace”, “thickmathspace”, “verythickmathspace” a “veryverythickmathspace” yn werthoedd anghymeradwy ar gyfer darnau MathML a byddan nhw'n cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate radical, notation and menclose.
+MathML_DeprecatedMencloseNotationRadical=Mae'r gwerth “radical” yn cael ei anghymeradwyo o gymharu â phriodoledd “notation” elfen <menclose> a bydd yn cael ei dynnu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML or mfenced.
+MathML_DeprecatedMfencedElement=Mae priodoledd MathML nfenced yn anghymeradwy a bydd yn cael ei ddileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML, subscriptshift and superscriptshift.
+MathML_DeprecatedScriptShiftAttributes=Mae priodoleddau MathML “subscriptshift” a “superscriptshift” yn cael eu anghymeradwyo a byddant yn cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML, background, color, fontfamily, fontsize, fontstyle and fontweight.
+MathML_DeprecatedStyleAttributeWarning=Mae priodoleddau MathML “background”, “color”, “fontfamily”, “fontsize”, “fontstyle” a “fontweight” yn anghymeradwy a byddan nhw'n cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML and XLink.
+MathML_DeprecatedXLinkAttributeWarning=Mae priodoleddau XLink “href”, “type”, “show” ac “actuate” yn anghymreadwy ar elfennau MathML a byddant yn cael eu dileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML and STIXGeneral. %S is a documentation URL.
+MathML_DeprecatedStixgeneralOperatorStretchingWarning=Mae cefnogaeth ar gyfer rendro gweithredwyr MathML estynedig gyda ffontiau STIXGeneral yn anghymeradwy ac o bosib yn cael ei ddileu yn y dyfodol. Am fanylion am ffontiau diweddarach a fydd yn parhau i gael eu cefnogi, gweler %S.
+# LOCALIZATION NOTE: Do not translate MathML and scriptminsize.
+MathML_DeprecatedScriptminsizeAttributeWarning=Mae priodoledd MathML “scriptminsize” yn anghymeradwy ac efallai bydd yn cael ei ddileu yn y dyfodol.
+# LOCALIZATION NOTE: Do not translate MathML and scriptsizemultiplier.
+MathML_DeprecatedScriptsizemultiplierAttributeWarning=Mae priodoledd MathML “scriptsizemultiplier” yn anghymeradwy ac efallai bydd yn cael ei ddileu yn y dyfodol.
+WebShareAPI_Failed=Methodd y weithred rhannu.
+WebShareAPI_Aborted=Ataliwyd y weithred rhannu.
+# LOCALIZATION NOTE (UnknownProtocolNavigationPrevented): %1$S is the destination URL.
+UnknownProtocolNavigationPrevented=Wedi atal llywio i “%1$S” oherwydd protocol anhysbys.
+PostMessageSharedMemoryObjectToCrossOriginWarning=Methu postio neges sy'n cynnwys gwrthrych cof a rennir i ffenestr traws-darddiad.
+# LOCALIZATION NOTE: %S is the URL of the resource in question
+UnusedLinkPreloadPending=Nid yw'r yr adnodd ar “%S” rhag-lwythwyd gyda dolen rhag-lwythwyd wedi ei ddefnyddio o fewn ychydig eiliadau. Gwnewch yn siŵr fod holl briodoleddau'r tag rhag-lwytho wedi'u gosod yn gywir.
+
+# LOCALIZATION NOTE: Do not translate document.requestStorageAccess(), iframe, allow-same-origin and sandbox (though you may translate "sandboxed").
+RequestStorageAccessNullPrincipal=Nid oes modd galw document.requestStorageAccess() ar ddogfen gyda tharddiad aneglur, fel iframe blwch tywod heb allow-same-origin yn ei briodweddau blwch tywod.
+# LOCALIZATION NOTE: Do not translate document.requestStorageAccess(), iframe, allow-storage-access-by-user-activation and sandbox (though you may translate "sandboxed").
+RequestStorageAccessSandboxed=Nid oes modd galw document.requestStorageAccess() ar ddogfen mewn iframe blwch tywod heb allow-same-origin yn ei briodweddau blwch tywod.
+# LOCALIZATION NOTE: Do not translate document.requestStorageAccess() and iframe.
+RequestStorageAccessNested=Nid oes modd galw document.requestStorageAccess() mewn iframe nythog.
+# LOCALIZATION NOTE: Do not translate document.requestStorageAccess(). In some locales it may be preferable to not translate "event handler", either.
+RequestStorageAccessUserGesture=Nid oes modd galw document.requestStorageAccess() ond o fewn triniwr digwyddiad wedi ei gynhyrchu, tymor byr.
+# LOCALIZATION NOTE: Do not translate "Location" and "History".
+LocChangeFloodingPrevented=Gormod o alwadau i APIs Lleoliad neu Hanes o fewn cyfnod byr.
+FolderUploadPrompt.title = Cadarnhau'r Llwytho
+# LOCALIZATION NOTE: %S is the name of the folder the user selected in the file picker.
+FolderUploadPrompt.message = Ydych chi'n siŵr eich bod chi am lwytho pob ffeil o “%S”? Gwnewch hyn dim ond os ydych chi'n ymddiried yn y wefan.
+FolderUploadPrompt.acceptButtonLabel = Llwytho
+InputPickerBlockedNoUserActivation=Cafodd y dewisydd <input> ei rwystro oherwydd diffyg gweithredu gan y defnyddiwr.
+ExternalProtocolFrameBlockedNoUserActivation=Cafodd Iframe â phrotocol allanol ei rwystro oherwydd diffyg gweithredu gan y defnyddiwr, neu oherwydd nad oes digon o amser wedi mynd heibio ers i'r iframe olaf gael ei lwytho.
+MultiplePopupsBlockedNoUserActivation=Cafodd agor llamlenni lluosog eu rhwystro oherwydd diffyg gweithredu gan y defnyddiwr.
+# LOCALIZATION NOTE: %S is the URL of the preload that was ignored.
+PreloadIgnoredInvalidAttr=Anwybyddwyd rhaglwytho %S oherwydd gwerthoedd anhysbys “as” neu “type”, neu briodoledd “media” nad oedd yn cyfateb.
diff --git a/l10n-cy/dom/chrome/global-strres.properties b/l10n-cy/dom/chrome/global-strres.properties
new file mode 100644
index 0000000000..bebf6dc626
--- /dev/null
+++ b/l10n-cy/dom/chrome/global-strres.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+16389=Digwyddodd gwall anhysbys (%1$S)
diff --git a/l10n-cy/dom/chrome/global.dtd b/l10n-cy/dom/chrome/global.dtd
new file mode 100644
index 0000000000..661fb351f4
--- /dev/null
+++ b/l10n-cy/dom/chrome/global.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY locale.dir "ltr">
diff --git a/l10n-cy/dom/chrome/layout/HtmlForm.properties b/l10n-cy/dom/chrome/layout/HtmlForm.properties
new file mode 100644
index 0000000000..589decedf6
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/HtmlForm.properties
@@ -0,0 +1,43 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Reset=Ailosod
+Submit=Cyflwyno Ymholiad
+Browse=Pori…
+FileUpload=Llwytho Ffeil i Fyny
+DirectoryUpload=Dewis Ffolder i'w Lwytho
+DirectoryPickerOkButtonLabel=Llwytho
+ForgotPostWarning=Mae'r ffurflen yn cynnwys enctype=%S, ond nid method=post.  Cyflwyno fel rheol gyda method=GET a dim enctype yn lle hynny.
+ForgotFileEnctypeWarning=Mae'r ffurflen yn cynnwys mewnbwn ffeil ond mae method=POST a enctype=multipart/form-data ar goll ar y ffurflen.  Ni fydd y ffeil yn cael ei hanfon.
+# LOCALIZATION NOTE (DefaultFormSubject): %S will be replaced with brandShortName
+DefaultFormSubject=Form Post o %S
+CannotEncodeAllUnicode=Cafodd ffurflen ei chyflwyno mewn amgodiad %S nad yw'n gallu amgodio'r holl nodau Unicode, fell gall mewnbwn defnyddiwr gael ei lygru. Er mwyn osgoi'r broblem hon, dylai'r dudalen gael ei newid fel bod y ffurflen yn cael ei chyflwyno mewn amgodiad UTF-8 un ai drwy newid y amgodiad y dudalen i UTF-8 neu drwy bennu accept-charset=utf-8 ar elfen y ffurflen.
+AllSupportedTypes=Pob Math a Gynhelir
+# LOCALIZATION NOTE (NoFileSelected): this string is shown on a
+# <input type='file'> when there is no file selected yet.
+NoFileSelected=Heb ddewis ffeil.
+# LOCALIZATION NOTE (NoFilesSelected): this string is shown on a
+# <input type='file' multiple> when there is no file selected yet.
+NoFilesSelected=Heb ddewis ffeiliau.
+# LOCALIZATION NOTE (NoDirSelected): this string is shown on a
+# <input type='file' directory/webkitdirectory> when there is no directory
+# selected yet.
+NoDirSelected=Dim cyfeiriadur wedi'i ddewis.
+# LOCALIZATION NOTE (XFilesSelected): this string is shown on a
+# <input type='file' multiple> when there are more than one selected file.
+# %S will be a number greater or equal to 2.
+XFilesSelected=Wedi dewis %S ffeil.
+ColorPicker=Dewis lliw
+# LOCALIZATION NOTE (AndNMoreFiles): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# This string is shown at the end of the tooltip text for <input type='file'
+# multiple> when there are more than 21 files selected (when we will only list
+# the first 20, plus an "and X more" line). #1 represents the number of files
+# minus 20 and will always be a number equal to or greater than 2. So the
+# singular case will never be used.
+AndNMoreFiles=a 0 arall;a #1 arall;a #1 arall;a #1 arall;a #1 arall;a #1 arall
+# LOCALIZATION NOTE (DefaultSummary): this string is shown on a <details> when
+# it has no direct <summary> child. Google Chrome should already have this
+# string translated.
+DefaultSummary=Manylion
diff --git a/l10n-cy/dom/chrome/layout/MediaDocument.properties b/l10n-cy/dom/chrome/layout/MediaDocument.properties
new file mode 100644
index 0000000000..392b119744
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/MediaDocument.properties
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#LOCALIZATION NOTE (ImageTitleWithDimensions2AndFile): first %S is filename, second %S is type, third %S is width and fourth %S is height
+#LOCALIZATION NOTE (ImageTitleWithoutDimensions): first %S is filename, second %S is type
+#LOCALIZATION NOTE (ImageTitleWithDimensions2): first %S is type, second %S is width and third %S is height
+#LOCALIZATION NOTE (ImageTitleWithNeitherDimensionsNorFile): first %S is type
+#LOCALIZATION NOTE (MediaTitleWithFile): first %S is filename, second %S is type
+#LOCALIZATION NOTE (MediaTitleWithNoInfo): first %S is type
+ImageTitleWithDimensions2AndFile=%S (Delwedd %S, %S × %S picsel)
+ImageTitleWithoutDimensions=%S (Delwedd %S)
+ImageTitleWithDimensions2=(Delwedd %S, %Sx%S picsel)
+ImageTitleWithNeitherDimensionsNorFile=(Gwrthrych %S)
+MediaTitleWithFile=%S (Gwrthrych %S)
+MediaTitleWithNoInfo=(Gwrthrych %S)
+
+InvalidImage=Nid oes modd dangos delwedd “%S” am ei fod yn cynnwys gwallau.
+ScaledImage=Graddiwyd (%S%%)
+
+TitleWithStatus=%S - %S
diff --git a/l10n-cy/dom/chrome/layout/css.properties b/l10n-cy/dom/chrome/layout/css.properties
new file mode 100644
index 0000000000..261b203c8a
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/css.properties
@@ -0,0 +1,46 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+MimeNotCss=Cafodd dalen steil %1$S ddim ei llwytho am nad oedd ei fath MIME, “%2$S”, yn “text/css”.
+MimeNotCssWarn=Cafodd y ddalen steil %1$S ei llwytho fel CSS er nad yw ei fath MIME type, "%2$S", yn “text/css”.
+
+PEDeclDropped=Datganiad wedi ei hepgor.
+PEDeclSkipped=Neidio i'r datganiad nesaf.
+PEUnknownProperty=Priodwedd anhysbys ‘%1$S’.
+PEValueParsingError=Gwall didoli gwerth priodwedd ‘%1$S’.
+PEUnknownAtRule=At-rule anhysbys neu wall didoli at-rule ‘%1$S’.
+PEMQUnexpectedOperator=Gweithredwr annisgwyl yn y rhestr cyfrwng.
+PEMQUnexpectedToken=Tocyn anniagwyl ‘%1$S’ yn y rhestr cyfrwng.
+PEAtNSUnexpected=Tocyn annisgwyl o fewn @namespace: ‘%1$S’.
+PEKeyframeBadName=Dynodwr disgwyliedig @rheolau keyframes.
+PEBadSelectorRSIgnored=Anwybyddwyd set rheolau oherwydd dewisydd gwallus.
+PEBadSelectorKeyframeRuleIgnored=Anwybyddwyd rheol keyframe oherwydd adran wael.
+PESelectorGroupNoSelector=Disgwyl dewisydd.
+PESelectorGroupExtraCombinator=Cyfuniadur rhydd.
+PEClassSelNotIdent=Disgwyl dynodydd dewisydd dosbarth ond canfod ‘%1$S’.
+PETypeSelNotType=Disgwyl enw elfen neu '*' ond canfod ‘%1$S’.
+PEUnknownNamespacePrefix=Rhagddodiad bwlch enw anhysbys ‘%1$S’.
+PEAttributeNameExpected=Disgwyl dynodydd enw priodoledd ond canfod ‘%1$S’.
+PEAttributeNameOrNamespaceExpected=Disgwyl enw priodoledd neu gyswllt ond canfod ‘%1$S’.
+PEAttSelNoBar=Disgwyl '|' ond canfod ‘%1$S’.
+PEAttSelUnexpected=Dewisydd priodoledd mewn tocyn annisgwyl: ‘%1$S’.
+PEAttSelBadValue=Disgwyl dynodydd neu linyn gwerth mewn dewisydd priodoledd ond canfod ‘%1$S’.
+PEPseudoSelBadName=Disgwyl dynodydd ffug ddosbarth neu ffug elfen ond canfod ‘%1$S’.
+PEPseudoSelEndOrUserActionPC=Disgwyl diwedd dewisydd neu gweithred defnyddiwr siwdo ddosbarth ar ôl siwdo elfen ond canfod ‘%1$S’.
+PEPseudoSelUnknown=Ffug ddosbarth neu ffug elfen ‘%1$S’.
+PENegationBadArg=Ymresymiad coll mewn ffug ddosbarth negydydd ‘%1$S’.
+PEPseudoClassArgNotIdent=Disgwyl dynodwr paramedr ffug-ddosbarth ond wedi canfod ‘%1$S’.
+PEColorNotColor=Disgwyl lliw ond canfod ‘%1$S’.
+PEParseDeclarationDeclExpected=Disgwyl cyhoeddiad ond canfod ‘%1$S’.
+PEUnknownFontDesc=Disgrifiad anhysbys ‘%1$S’ yn @font-face rule.
+PEMQExpectedFeatureName=Disgwyl enw nodwedd cyfrwng ond wedi canfod '‘%1$S’.
+PEMQNoMinMaxWithoutValue=Rhaid i nodweddion cyfrwng sydd â min- neu max- fod â gwerth.
+PEMQExpectedFeatureValue=Canfod gwerth annilys ar gyfer nodwedd cyfrwng.
+PEExpectedNoneOrURL=Disgwyl 'none' neu URL ond canfod ‘%1$S’.
+PEExpectedNoneOrURLOrFilterFunction=Disgwyl 'none', URL, neu swyddogaethau hidl ond canfod ‘%1$S’.
+
+PEDisallowedImportRule=Nid yw rheolau @import yn ddilys eto mewn taflenni arddull wedi'u hadeiladu.
+
+TooLargeDashedRadius=Mae radiws yr ymyl yn rhy fawr ar gyfer arddull toredig (y terfyn yw 100000px). Rendro fel solet.
+TooLargeDottedRadius=Mae radiws yr ymyl yn rhy fawr ar gyfer arddull dotiog (y terfyn yw 100000px). Rendro fel solet.
diff --git a/l10n-cy/dom/chrome/layout/htmlparser.properties b/l10n-cy/dom/chrome/layout/htmlparser.properties
new file mode 100644
index 0000000000..d3f7cd74c8
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/htmlparser.properties
@@ -0,0 +1,134 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Encoding warnings and errors
+EncNoDeclarationFrame=Nid oedd amgodio nod dogfen fframeddig wedi ei datgan. Gall y ddogfen ymddangos yn wahanol heb y ddogfen yn ei fframio.
+EncNoDeclarationPlain=Nid yw amgodio nod y ddogfen testun plaen wedi ei ddatgan. Bydd y ddogfen yn cael ei ffurfio gyda thestun annealladwy yn ffurfweddiad rhai porwyr os fydd y ddogfen yn cynnwys nodau y tu allan i ystod nodau US-ASCII. Rhaid i amgodio nod ffeil gael ei ddatgan yn y ffeil protocol trosglwyddo neu mae angen i'r ffeil ddefnyddio marc trefn beit fel llofnod amgodio.
+EncNoDeclaration=Nid yw amgodio nod y ddogfen HTML wedi ei ddatgan. Bydd y ddogfen yn cael ei ffurfio gyda thestun annealladwy yn ffurfweddiad rhai porwyr os fydd y ddogfen yn cynnwys nodau y tu allan i ystod nodau US-ASCII. Rhaid i amgodio nod ffeil gael ei ddatgan yn y ffeil protocol trosglwyddo neu mae angen i'r ffeil ddefnyddio marc trefn beit fel llofnod amgodio.
+EncLateMetaFrame=Nid oedd datganiad amgodiad nod y ddogfen HTML fframedig wedi ei chanfod wrth rag sganio 1024 cyntaf y ffeil. Wrth edrych arni heb y fframio dogfen bydd y dudalen yn ail-lwytho'n awtomatig. Mae angen symud y datganiad amgodio i fod o fewn y 1024 beit cyntaf y ffeil.
+EncLateMeta=Nid oedd datganiad amgodiad nod y ddogfen HTML wedi ei chanfod wrth rag sganio 1024 cyntaf y ffeil. Wrth edrych arni heb y fframio dogfen bydd y dudalen yn ail-lwytho'n awtomatig. Mae angen symud y datganiad amgodio i fod o fewn y 1024 beit cyntaf y ffeil.
+EncLateMetaReload=Cafodd y dudalen ei ail lwytho gan na chanfuwyd datganiad amgodio nod y ddogfen HTML wrth rag sganio 1024 beit cyntaf y ffeil. Mae angen symud y datganiad amgodio i fod o fewn y 1024 beit cyntaf y ffeil.
+EncLateMetaTooLate=Canfuwyd datganiad amgodiad nod y ddogfen yn rhy hwyr i greu effaith. Mae angen symud y datganiad amgodio i fod o fewn y 1024 beit cyntaf y ffeil.
+EncMetaUnsupported=Datganwyd amgodiad nod sydd ddim yn cael ei gynnal ar gyfer y ddogfen HTML gan ddefnyddio tag meta. Anwybyddwyd y datganiad.
+EncProtocolUnsupported=Datganwyd amgodiad nod sydd heb ei gynnal ar lefel protocol trosglwyddo. Anwybyddwyd y datganiad.
+EncBomlessUtf16=Canfuwyd testun Basic Lladin yn unig wedi ei amgodio i UTF-16 heb farc trefn beit a heb ddatganiad lefel protocol trosglwyddo. Mae amgodio'r cynnwys i UTF-16 yn aneffeithiol a dylai'r amgodiad fod wedi ei ddatgan beth bynnag.
+EncMetaUtf16=Defnyddiwyd tag meta i ddatgan amgodiad nod fel UTF-16. Cafodd hyn ei ddehongli fel datganiad UTF-8 yn lle hynny.
+EncMetaUserDefined=Cafodd tag meta ei ddefnyddio i ddatgan nod amgodio fel defnyddiwr diffiniedig x. Cafodd ei ddehongli fel datganiad windows-1252 yn lle hynny ar gyfer cydnawsedd gyda hen ffontiau wedi eu cam amgodio'n fwriadol. Dylai'r wefan symud i ddefnyddio Unicode.
+
+# The bulk of the messages below are derived from
+# https://hg.mozilla.org/projects/htmlparser/file/1f633cef7de7/src/nu/validator/htmlparser/impl/ErrorReportingTokenizer.java
+# which is available under the MIT license.
+
+# Tokenizer errors
+errGarbageAfterLtSlash=Sbwriel ar ôl “</”.
+errLtSlashGt=Wedi gweld “</>”. Rhesymau tebygol “<” (escape as “&lt;”) Heb ddianc neu tag diwedd wedi ei gamdeipio.
+errCharRefLacksSemicolon=Nid yw'r cyfeirnod nod wedi ei deffynnu gan hanner colon.
+errNoDigitsInNCR=Dim nodau yng nhyfeiriad nod rhifol.
+errGtInSystemId=“>” mewn dynodydd system.
+errGtInPublicId=“>” mewn new cyhoeddus.
+errNamelessDoctype=Doctype dienw.
+errConsecutiveHyphens=Nid yw cysylltnodau dilynol wedi terfynu sylw. Ni chaniateir “--” o fewn sylw, ond mae e.e. “- -” yn iawn.
+errPrematureEndOfComment=Sylw'n dod i ben yn rhy sydyn. Defnyddiwch “-->” i derfynu sylw'n briodol.
+errBogusComment=Sylw gau.
+errUnquotedAttributeLt=“<” mewn gwerth priodwedd annyfynedig. Achos tebygol: Coll “>” yn syth o'i flaen.
+errUnquotedAttributeGrave=Mae “`” yn werth priodwedd heb ei ddyfynnu. Achos tebygol: Defnyddio nod anghywir fel dyfyniad.
+errUnquotedAttributeQuote=Mae dyfyniad yn werth priodwedd heb ei ddyfynnu. Achos tebygol: Priodweddau'n rhedeg gyda'i gilydd neu linyn ymholiad URL mewn gwerth priodwedd heb ddyfyniad.
+errUnquotedAttributeEquals=“=” mewn gwerth priodwedd heb ei ddyfynnu. Achos tebygol: Priodweddau'n rhedeg gyda'i gilydd neu linyn ymholiad URL mewn gwerth priodwedd heb ddyfyniad.
+errSlashNotFollowedByGt=Nid oedd slaes yn cael ei ddilyn yn syth gan“>”.
+errNoSpaceBetweenAttributes=Dim bwlch rhwng priodweddau.
+errUnquotedAttributeStartLt="<" ar ddechrau gwerth priodwedd heb ei ddyfynnu. Achos tebygol: “>” coll yn syth o'i flaen.
+errUnquotedAttributeStartGrave=“`” ar ddechrau gwerth priodwedd heb gyfeiriad. Achos tebygol: Defnyddio'r nod anghywir fel dyfyniad.
+errUnquotedAttributeStartEquals=“=” ar gychwyn gwerth priodwedd heb ddyfyniad. Achos tebygol: Arwydd hafal dyblyg strae.
+errAttributeValueMissing=Gwerth priodwedd ar goll.
+errBadCharBeforeAttributeNameLt=Wedi gweld“<” pan yn disgwyl enw priodwedd. Achos tebygol: “>” coll yn syth o'i flaen.
+errEqualsSignBeforeAttributeName=Gweld “=” pan yn disgwyl enw priodwedd. Achos tebygol: Enw priodwedd ar goll.
+errBadCharAfterLt=Nod gwael ar ôl “<”. Achos tebygol: Heb ddianc “<”. Ceisiwch ei ddianc fel “&lt;”.
+errLtGt=Gweld “<>”. Achos tebygol: Heb ddianc “<” (dianc fel “&lt;”) neu tag cychwyn wedi ei gamdeipio.
+errProcessingInstruction=Gweld “<?”. Achos tebygol: Ceisio defnyddio cyfarwyddid proses XML yn HTML. (Nid yw cyfarwyddiadau prosesu XML yn cael eu cynnal yn HTML.)
+errUnescapedAmpersandInterpretedAsCharacterReference=Cafodd y llinyn sy'n dilyn “&” ei ddehongli fel nod cyfeirnod. (Dylai “&” fod wedi ei ddianc fel “&amp;”.)
+errNotSemicolonTerminated=Ni chafodd cyfeirnod nod enwyd ei derfynu gan hanner colon. (Neu dylai “&” fod wedi ei ddianc fel “&amp;”.)
+errNoNamedCharacterMatch=Nid yw “&” wedi cychwyn cyfeirnod nod. (Dylai “&” fod wedi ei ddianc fel “&amp;”.)
+errQuoteBeforeAttributeName=Gwelwyd dyfyniad pan yn disgwyl enw priodwedd. Achos tebygol: “=” ar goll yn union o'i flaen.
+errLtInAttributeName=“<” mewn enw priodwedd. Achos tebygol: “>” ar goll yn union o'i flaen.
+errQuoteInAttributeName=Dyfyniad o fewn enw priodwedd. Achos tebygol: Dyfyniad cyfatebol ar goll rhylw ynghynt.
+errExpectedPublicId=Disgwyl dynodwr cyhoeddus ynghynt ond diweddodd y doctype.
+errBogusDoctype=Doctype ffug.
+maybeErrAttributesOnEndTag=Roedd gan tag terfynnu briodweddau.
+maybeErrSlashInEndTag=Mae “/” strae ar ddiwedd tag terfynu.
+errNcrNonCharacter=Mae cyfeiriad nod yn estyn i an-nod.
+errNcrSurrogate=Mae cyfeiriad nod yn estyn i un benthyg.
+errNcrControlChar=Mae cyfeirnod nod yn estyn i un benthyg.
+errNcrCr=Estynnodd gyfeirnod rhifol i ddychwelydd.
+errNcrInC1Range=Estynnodd gyfeirnod rhifol i ystod rheolydd C1.
+errEofInPublicId=Diwedd ffeil o fewn dynodwr cyhoeddus.
+errEofInComment=Diwedd ffeil o fewn sylw.
+errEofInDoctype=Diwedd ffeil o fewn doctype.
+errEofInAttributeValue=Diwedd ffeil wedi ei gyrraedd o fewn gwerth priodwedd. Anwybyddu tag.
+errEofInAttributeName=Diwedd ffeil wedi digwydd o fewn enw priodwedd. Anwybyddu tag.
+errEofWithoutGt=Gweld diwedd ffeil heb derfyn tag blaenorol yn gorffen gyda “>”. Anwybyddu tag.
+errEofInTagName=Gweld diwedd ffeil wrth chwilio am enw tag. Anwybyddu tag.
+errEofInEndTag=Diwedd ffeil o fewn tag terfynnu. Anwybyddu tag.
+errEofAfterLt=Diwedd ffeil wedi “<”.
+errNcrOutOfRange=Cyfeirnod nod tu allan i ystod cymeradwy Unicode.
+errNcrUnassigned=Vyfeirnod nod yn estyn i bwynt cod heb ei ddynodi'n barhol.
+errDuplicateAttribute=Priodweddau dyblyg.
+errEofInSystemId=Diwedd ffeil o fewn dynodwr system.
+errExpectedSystemId=Disgwyl dynodwr system ond diweddodd y doctype.
+errMissingSpaceBeforeDoctypeName=Bwlch coll o flaen ewn doctype.
+errHyphenHyphenBang=“--!” wedi ei ganfod mewn sylw.
+errNcrZero=Cyfeirnod nod wedi estyn i sero.
+errNoSpaceBetweenDoctypeSystemKeywordAndQuote=Dim bwlch rhwng allweddair “SYSTEM” doctype a'r dyfyniad.
+errNoSpaceBetweenPublicAndSystemIds=Dim bwlch rhwng dynodwyr doctype cyhoeddus a system.
+errNoSpaceBetweenDoctypePublicKeywordAndQuote=Dim bwlch rhwng allweddair “PUBLIC” a'r dyfyniad.
+
+# Tree builder errors
+errDeepTree=Mae coeden y ddogfen yn rhy ddwfn. Bydd y goeden yn cael ei wastadau i fod yn 513 elfen o ddyfnder.
+errStrayStartTag2=Tag cychwyn strae “%1$S”.
+errStrayEndTag=Tag terfynnu strae “%1$S”.
+errUnclosedElements=Tag diweddu “%1$S” wedi ei weld, ond roedd yna elfennau agored.
+errUnclosedElementsImplied=Tag diweddu “%1$S” ymlhyg, ond roedd yna elfennau agored.
+errUnclosedElementsCell=Cafodd cell tabl ei gau ymlhyg, ond roedd yna elfennau agored.
+errStrayDoctype=Doctype strae.
+errAlmostStandardsDoctype=Doctype bron o fodd safonnol. Disgwyl “<!DOCTYPE html>”.
+errQuirkyDoctype=Doctype rhyfedd. Disgwyl “<!DOCTYPE html>”.
+errNonSpaceInTrailer=Nod dim bwlch yn nghynffon tudalen.
+errNonSpaceAfterFrameset=Dim bwlch ar ôl “frameset”.
+errNonSpaceInFrameset=Dim bwlch yn y “frameset”.
+errNonSpaceAfterBody=Nod dim bwlch ar ôl y corff.
+errNonSpaceInColgroupInFragment=Dim bwlch yn “colgroup” wrth ddidoli darn.
+errNonSpaceInNoscriptInHead=Nod dim bwlch o fewn “noscript” o fewn “head”.
+errFooBetweenHeadAndBody=Elfen “%1$S” rhwng “head” a “body”.
+errStartTagWithoutDoctype=Tag cychwyn wedi ei weld heb doctype yn gyntaf. Disgwyl “<!DOCTYPE html>”.
+errNoSelectInTableScope=Dim “select” yn nhabl cwmpas.
+errStartSelectWhereEndSelectExpected=Tag cychwyn “select” lle disgwyliwyd tag diweddu.
+errStartTagWithSelectOpen=Tag cychwyn “%1$S” gyda “select” ar agor.
+errBadStartTagInHead2=Tag cychwnyn gwael “%1$S” yn “head”.
+errBadStartTagInNoscriptInHead=Tag cychwyn gwael “%1$S” yn “noscript” yn “head”.
+errImage=Gweld tag cychwyn “image”.
+errFooSeenWhenFooOpen=Gweld tag cychwyn “%1$S” ond roedd elfen o'r un fath ar agor.
+errFooSeenWhenFooOpen2=Tag cychwynnol “%1$S” wedi'i weld ond roedd elfen o'r un math eisoes ar agor.
+errHeadingWhenHeadingOpen=Ni all y pennawd fod yn blentyn i bennawd arall.
+errFramesetStart=Gweld tag cychwyn “frameset”.
+errNoCellToClose=Dim cell i'w chau.
+errStartTagInTable=Gweld tag cychwyn “%1$S” mewn “table”.
+errFormWhenFormOpen=Gweld tag cychwyn “form”, ond roedd elfen “form” gweithredol yn barod. Nid oes caniatâd i ffurflenni nythiog. Anwybyddu'r tag.
+errTableSeenWhileTableOpen=Tag cychwynnol ar gyfer “table” wedi ei weld ond y “table” blaenorol ar agor o hyd.
+errStartTagInTableBody=Tag cychwyn “%1$S” yng nghorff y tabl.
+errEndTagSeenWithoutDoctype=Tag diweddu wedi ei weld heb weld y doctype yn gyntaf. Disgwyl “<!DOCTYPE html>”.
+errEndTagAfterBody=Gweld tag diweddu wedi i “body” gael ei gau.
+errEndTagSeenWithSelectOpen=Tag diweddu “%1$S” gyda “select” ar agor.
+errGarbageInColgroup=Sbwriel o fewn darn “colgroup”.
+errEndTagBr=Tag diweddu “br”.
+errNoElementToCloseButEndTagSeen=Dim elfen “%1$S” yn y sgôp ond wedi gweld tag diweddu “%1$S”.
+errHtmlStartTagInForeignContext=Tag cychwyn HTML “%1$S” mewn cydestun bwlch enw dieithr.
+errTableClosedWhileCaptionOpen=“table” wedi cau ond roedd “caption” dal ar agor.
+errNoTableRowToClose=Dim rhes tabl i'w chau.
+errNonSpaceInTable=Nodau dim bwlch wedi eu camosod o fewn tabl.
+errUnclosedChildrenInRuby=Plant heb eu cau o fewn “ruby”.
+errStartTagSeenWithoutRuby=Tag cychwyn “%1$S” wedi ei weld heb yr elfen “ruby” ar agor.
+errSelfClosing=Cystrawen hunan gau (“/>”) yn cael ei ddefnyddio mewn elfen HTML anrymus. Anwybyddu'r gwrthdaro a'i drin fel tag cychwyn.
+errNoCheckUnclosedElementsOnStack=Elfennau heb eu cau ar y stac.
+errEndTagDidNotMatchCurrentOpenElement=Nid yw'r tag diweddu “%1$S” yn cydweddu ag enw'r elfen sydd ar agor ar hyn o bryd (“%2$S”).
+errEndTagViolatesNestingRules=Mae tag diweddu “%1$S” yn torri rheolau nythu.
+errEndWithUnclosedElements=Tag diweddu “%1$S” wedi ei weld, ond roedd yna elfennau heb eu cau.
diff --git a/l10n-cy/dom/chrome/layout/layout_errors.properties b/l10n-cy/dom/chrome/layout/layout_errors.properties
new file mode 100644
index 0000000000..e66f4bd297
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/layout_errors.properties
@@ -0,0 +1,55 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+ImageMapRectBoundsError=Nid yw priodwedd “coords” tag <area shape="rect"> yn fformat “chwith,brig,de,gwaelod”.
+ImageMapCircleWrongNumberOfCoords=Nid yw priodoledd “coords” y tag <area shape="circle"> yn y fformat “center-x,center-y,radius”.
+ImageMapCircleNegativeRadius=Mae gan briodoledd “coords” y tag <area shape="circle"> radiws negyddol.
+ImageMapPolyWrongNumberOfCoords=Nid yw priodwedd “coords” tag <area shape="poly"> yn fformat “x1,y1,x2,y2…”.
+ImageMapPolyOddNumberOfCoords=Nid yw priodwedd "coords" tag <area shape="poly"> yn brin o'r cyfesurun olaf "y" (y fformat cywir yw "x1,y1,x2,y2 …").
+
+TablePartRelPosWarning=Mae gosod perthynol o resi tabl a rhesi grŵp yn cael ei gynnal nawr. Efallai byd angen diweddaru'r wefan os yw'n dibynnu ar y nodwedd yma.
+ScrollLinkedEffectFound2=Mae'r wefan hon i weld yn defnyddio effeithiau gosod sgrolio cysylltiedig. Efallai na fydd hwn yn gweithio'n dda gyda phanio anghydamseredig; gw. https://developer.mozilla.org/docs/Mozilla/Performance/ScrollLinkedEffects am wybodaeth bellach ac ymuno â'r drafodaeth ar yr offer a'r nodweddion cysylltiedig!
+
+## LOCALIZATION NOTE(CompositorAnimationWarningContentTooLargeArea):
+## %1$S is an integer value of the area of the frame
+## %2$S is an integer value of the area of a limit based on the viewport size
+CompositorAnimationWarningContentTooLargeArea=Nid oes modd rhedeg animeiddiad ar y cyfansoddwr gan fod maint y ffrâm (%1$S) yn rhy fawr mewn perthynas â'r viewport (mwy na %2$S)
+## LOCALIZATION NOTE(CompositorAnimationWarningContentTooLarge2):
+## (%1$S, %2$S) is a pair of integer values of the frame size
+## (%3$S, %4$S) is a pair of integer values of a limit based on the viewport size
+## (%5$S, %6$S) is a pair of integer values of an absolute limit
+CompositorAnimationWarningContentTooLarge2=Nid oes modd rhedeg yr animeiddio ar y cyfansoddwr oherwydd bod maint y ffrâm (%1$S, %2$S) yn rhy fawr mewn perthynas â'r porth gweld (yn fwy na (%3$S, %4$S)) neu'n yn fwy na'r gwerth mwyaf sy'n cael ei ganiatáu (%5$S, %6$S)
+## LOCALIZATION NOTE(CompositorAnimationWarningTransformBackfaceVisibilityHidden):
+## 'backface-visibility: hidden' is a CSS property, don't translate it.
+CompositorAnimationWarningTransformBackfaceVisibilityHidden=Animeiddio 'backface-visibility: nid oes modd rhedeg trawsnewidiadau cudd ar y cyfansoddwr
+## LOCALIZATION NOTE(CompositorAnimationWarningTransformSVG,
+##                   CompositorAnimationWarningTransformWithGeometricProperties,
+##                   CompositorAnimationWarningTransformWithSyncGeometricAnimations,
+##                   CompositorAnimationWarningTransformFrameInactive,
+##                   CompositorAnimationWarningOpacityFrameInactive):
+## 'transform' and 'opacity' mean CSS property names, don't translate it.
+CompositorAnimationWarningTransformSVG=Nid oes modd rhedeg animeiddiadau 'transform' ar elfennau o drawsnewidiadau SVG yn y cyfansoddwr
+CompositorAnimationWarningTransformWithGeometricProperties=Nid oes modd rhedeg animeiddiadau 'transform' yn y cyfansoddwr pan mae priodoleddau geometrig wedi eu hanimeiddio ar yr un elfen ar yr un pryd
+CompositorAnimationWarningTransformWithSyncGeometricAnimations=Nid oes modd rhedeg animeiddio'r ‘trawsffurfio’ yn y cyfansoddwr am y dylai gael ei gydamseru gydag animeiddiadau priodweddau geometrig gychwynnodd ar yr un pryd
+CompositorAnimationWarningTransformFrameInactive=Nid oes modd rhedeg animeiddiadau yn y cyfansoddwr gan nad oedd y ffrâm wedi ei nodi'n fyw ar gyfer animeiddio 'transform'
+CompositorAnimationWarningTransformIsBlockedByImportantRules=Ni all animeiddio trawsffurfiad gael ei redeg ar y cyfansoddwr oherwydd bod rheolau pwysig yn gwrthwneud priodweddau sy'n gysylltiedig â thrawsffurfiad
+CompositorAnimationWarningOpacityFrameInactive=Nid oes modd rhedeg animeiddiadau yn y cyfansoddwr gan nad oedd y ffrâm wedi ei nodi'n fyw ar gyfer animeiddio 'opacity'
+CompositorAnimationWarningHasRenderingObserver=Nid oes modd rhedeg animeiddio ar y cyfosodwr gan fod gan yr elfen wylwyr rendro (-moz-element neu glipio/masgio SVG)
+
+CompositorAnimationWarningHasCurrentColor=Nid oes modd rhedeg animeiddiadau o ‘background-color’ ar y cyfansoddwr gyda keyframe ‘current-colour’.
+
+## LOCALIZATION NOTE: Do not translate zoom, calc(), "transform", "transform-origin: 0 0"
+ZoomPropertyWarning=Mae'r dudalen hon yn defnyddio'r briodwedd ansafonol “zoom”. Ystyriwch ddefnyddio calc() yn y gwerthoedd priodwedd perthnasol, neu ddefnyddio “transform” ynghyd â “transform-origin: 0 0”.
+
+## LOCALIZATION NOTE(PrincipalWritingModePropagationWarning):
+## Do not translate <html>, <body>, CSS, "writing-mode", "direction", "text-orientation", :root, and "The Principal Writing Mode" because they are technical terms.
+PrincipalWritingModePropagationWarning=Wrth rendro'r elfen <html>, mae gwerthoedd a ddefnyddir priodweddau CSS “writing-mode”, “direction”, a “text-orientation” ar yr elfen <html> o werthoedd cyfrifedig yr elfen <body>, nid o werthoedd yr elfen <html> ei hun. Ystyriwch osod yr eiddo hyn ar: ffug-ddosbarth gwraidd CSS. Am fwy o wybodaeth darllenwch “The Principal Writing Mode” yn https://www.w3.org/TR/css-writing-modes-3/#principal-flow
+
+## LOCALIZATION NOTE(ScrollAnchoringDisabledInContainer):
+## %1$S is an integer value with the total number of adjustments
+## %2$S is a floating point value with the average distance adjusted
+## %3$S is a floating point value with the total adjusted distance
+ScrollAnchoringDisabledInContainer=Cafodd angori sgrolio ei analluogi mewn cynhwysydd sgrolio oherwydd gormod o addasiadau yn olynol (%1$S) gyda rhy ychydig o bellter (cyfartaledd %2$S px, cyfanswm %3$S px).
+
+ForcedLayoutStart=Gorfodwyd y cynllun cyn i'r dudalen gael ei llwytho'n llawn. Os nad yw taflenni arddull wedi'u llwytho eto gall hyn achosi fflach o gynnwys heb ei stilio.
diff --git a/l10n-cy/dom/chrome/layout/printing.properties b/l10n-cy/dom/chrome/layout/printing.properties
new file mode 100644
index 0000000000..cd58902adb
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/printing.properties
@@ -0,0 +1,56 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Page number formatting
+## @page_number The current page number
+#LOCALIZATION NOTE (pageofpages): Do not translate %ld in the following line.
+# Place the word %ld where the page number and number of pages should be
+# The first %ld will receive the the page number
+pagenumber=%1$d
+
+# Page number formatting
+## @page_number The current page number
+## @page_total The total number of pages
+#LOCALIZATION NOTE (pageofpages): Do not translate %ld in the following line.
+# Place the word %ld where the page number and number of pages should be
+# The first %ld will receive the the page number
+# the second %ld will receive the total number of pages
+pageofpages=%1$d o %2$d
+
+PrintToFile=Argraffu i Ffeil
+print_error_dialog_title=Gwall Argraffydd
+printpreview_error_dialog_title=Gwall Rhagolwg Argraffu
+
+# Printing error messages.
+#LOCALIZATION NOTE: Some of these messages come in pairs, one
+# for printing and one for print previewing.  You can remove that
+# distinction in your language by removing the entity with the _PP
+# suffix; then the entity without a suffix will be used for both.
+# You can also add that distinction to any of the messages that don't
+# already have it by adding a new entity with a _PP suffix.
+#
+# For instance, if you delete PERR_GFX_PRINTER_DOC_IS_BUSY_PP, then
+# the PERR_GFX_PRINTER_DOC_IS_BUSY message will be used for that error
+# condition when print previewing as well as when printing.  If you
+# add PERR_FAILURE_PP, then PERR_FAILURE will only be used when
+# printing, and PERR_FAILURE_PP will be used under the same conditions
+# when print previewing.
+#
+PERR_FAILURE=Digwyddodd gwall anhysbys wrth argraffu.
+
+PERR_ABORT=Terfynwyd y gwaith argraffu.
+PERR_NOT_AVAILABLE=Nid yw rhai swyddogaethau argraffu ar gael.
+PERR_NOT_IMPLEMENTED=Nid yw peth ffrwythiant wedi ei weithredu eto.
+PERR_OUT_OF_MEMORY=Nid oes digon o gof rhydd ar gael i argraffu.
+PERR_UNEXPECTED=Gwall annisgwyl wrth argraffu.
+
+PERR_GFX_PRINTER_NO_PRINTER_AVAILABLE=Dim argraffyddion ar gael.
+PERR_GFX_PRINTER_NO_PRINTER_AVAILABLE_PP=Dim argraffyddion ar gael, methu dangos rhagolwg argraffu.
+PERR_GFX_PRINTER_NAME_NOT_FOUND=Nid oedd modd dangos y dewis argraffydd.
+PERR_GFX_PRINTER_COULD_NOT_OPEN_FILE=Methu agor ffeil allbwn i'r ffeil ei hargraffu.
+PERR_GFX_PRINTER_STARTDOC=Methodd yr argraffu wrth gychwyn y gwaith argraffu.
+PERR_GFX_PRINTER_ENDDOC=Methodd yr argraffu wrth gwblhau'r gwaith argraffu.
+PERR_GFX_PRINTER_STARTPAGE=Methodd yr argraffu wrth gychwyn y dudalen.
+PERR_GFX_PRINTER_DOC_IS_BUSY=Methu argraffu'r ddogfen hon eto, mae'n cael ei llwytho.
+PERR_GFX_PRINTER_DOC_IS_BUSY_PP=Methu creu rhagolwg argraffu'r ddogfen yma eto, mae'n dal i gael ei llwytho.
diff --git a/l10n-cy/dom/chrome/layout/xmlparser.properties b/l10n-cy/dom/chrome/layout/xmlparser.properties
new file mode 100644
index 0000000000..e43372f4e8
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/xmlparser.properties
@@ -0,0 +1,48 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Map Expat error codes to error strings
+1 = dim cof ar ôl
+2 = gwall cystrawen
+3 = heb ganfod elfen gwraidd
+4 = heb ffurf dda
+5 = tocyn digau
+6 = nod rhannol
+7 = tag anghydweddiad
+8 = priodoledd ddyblyg
+9 = sothach ar ôl elfen dogfen
+10 = cyfeiriad paramedr endid anghyfreithlon
+11 = endid anniffiniedig
+12 = cyfeiriad endid ailadroddus
+13 = endid anghydamseredig
+14 = cyfeiriad at rif nod annilys
+15 = cyfeiriad at endid deuaidd
+16 = cyfeiriad at endid allanol yn y briodoledd
+17 = Nid yw datganiad testun neu XML ar gychwyn yr endiid
+18 = amgodio anhysbys
+19 = mae'r amgodio sydd wedi ei bennu yn natganiad XML yn anghywir
+20 = adran CDATA digau
+21 = gwall wrth brosesu cyfeirnod endyd allanol
+22 = nid yw'r ddogfen yn sefyll ei hun
+23 = cyflwr didolwr annisgwyl
+24 = endid wedi ei gyhoeddi mewn endid paramedr
+27 = rhagosodiad heb ei rwymo i ofod enw
+28 = rhaid peidio dad-ddatgan rhagosodiad
+29 = markup anghyflawn ym mharamedr endid
+30 = Datganiad XML heb ei ffurfio’n briodol
+31 = datganiad testun heb ei ffurfio'n briodol
+32 = nod(au) anghyfreithlon yn enw cyhoeddus
+38 = rhaid i ragosodiad ar gadw (xml) beidio bod heb ei ddatgan na'i rwymo i enw bwlchenw arall
+39 = rhaid i ragosodiad (xmlns) gadwyd peidio bod wedi ei ddatgan na'n ddiddatgan
+40 = rhaid i ragosodiad fod heb ei rwymo i un o'r enwau bwlchenw ar gadw
+
+# %1$S is replaced by the Expat error string, may be followed by Expected (see below)
+# %2$S is replaced by URL
+# %3$u is replaced by line number
+# %4$u is replaced by column number
+XMLParsingError = Gwall didoli XML: %1$S\nLleoliad: %2$S\nRhif Llinell %3$u, Colofn %4$u:
+
+# %S is replaced by a tag name.
+# This gets appended to the error string if the error is mismatched tag.
+Expected = . Disgwylir: </%S>.
diff --git a/l10n-cy/dom/chrome/layout/xul.properties b/l10n-cy/dom/chrome/layout/xul.properties
new file mode 100644
index 0000000000..fbf3becb82
--- /dev/null
+++ b/l10n-cy/dom/chrome/layout/xul.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+PINotInProlog=Nid yw'r cyfarwyddid prosesu <?%1$S?> yn cael unrhyw effaith y tuallan i'r prolog bellach (gw. gwall 360119).
diff --git a/l10n-cy/dom/chrome/mathml/mathml.properties b/l10n-cy/dom/chrome/mathml/mathml.properties
new file mode 100644
index 0000000000..3778cd6203
--- /dev/null
+++ b/l10n-cy/dom/chrome/mathml/mathml.properties
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+InvalidChild=Nod annilys: Nid yw <%1$S> yn cael ei ganiatáu fel plentyn <%2$S>.
+ChildCountIncorrect=Tagio annilys: Nifer anghywir o blant ar gyfer tag <%1$S/>.
+DuplicateMprescripts=Tagio annilys: Mwy nag un <mprescripts/>yn <mmultiscripts/>.
+# LOCALIZATION NOTE:  The first child of <mmultiscript/> is the base, that is the element to which scripts are attached.
+NoBase=Iaith tagio annilys: Disgwyl un elfen Sail yn <mmultiscripts/>.  Canfod dim.
+SubSupMismatch=Tagio annilys: : Pâr uwchysgrif/isysgrif anghyflawn yn <mmultiscripts/>.
+
+# LOCALIZATION NOTE:  When localizing the single quotes ('), follow the conventions in css.properties for your target locale.
+AttributeParsingError=Gwall wrth ddidoli'r gwerth priodoledd '%1$S' am '%2$S' <%3$S/>.  Anwybyddwyd y briodoledd.
+AttributeParsingErrorNoTag=Gwall wrth ddidoli'r gwerth priodoledd '%1$S' for '%2$S'.  Anwybyddwyd y briodoledd.
+LengthParsingError=Gwall wrth ddidoli gwerth priodoledd MathML '%1$S' fel hyd.  Anwybyddwyd y briodoledd.
+UnitlessValuesAreDeprecated=Mae gwerthodd di-uned yn anghymeradwy yn MathML 3.
diff --git a/l10n-cy/dom/chrome/netError.dtd b/l10n-cy/dom/chrome/netError.dtd
new file mode 100644
index 0000000000..cb48951308
--- /dev/null
+++ b/l10n-cy/dom/chrome/netError.dtd
@@ -0,0 +1,96 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY loadError.label "Gwall Llwytho Tudalen">
+<!ENTITY retry.label "Ceisiwch Eto">
+
+<!-- Specific error messages -->
+
+<!ENTITY connectionFailure.title "Methu Cysylltu">
+<!ENTITY connectionFailure.longDesc "<p>Er bod y wefan i'w weld yn ddilys, nid oedd y porwr yn gallu creu cysylltiad.</p><ul><li>Efallai nad yw'r wefan ar gael dros dro? Ceisiwch eto.</li><li>Methu pori safleoedd eraill?  Gwiriwch gysylltiad y cyfrifiadur â'r rhwydwaith.</li><li>A yw eich cyfrifiadur a'r rhwydwaith wedi eu hamddiffyn gan fur cadarn neu ddirprwy? Mae gosodiadau anghywir yn gallu ymyrryd â phori'r we.</li></ul>">
+
+<!ENTITY deniedPortAccess.title "Cyfyngwyd ar y Porth am Resymau Diogelwch">
+<!ENTITY deniedPortAccess.longDesc "<p>Gofynnodd y cyfeiriad am borth (e.e. <q>mozilla.org:80</q> sef porth 80 ar mozilla.org) sy'n cael ei ddefnyddio am resymau <em>heblaw</em> pori'r We. Mae'r porwr wedi diddymu eich cais er eich diogelwch.</p>">
+
+<!ENTITY dnsNotFound.title "Heb Ganfod Cyfeiriad">
+<!ENTITY dnsNotFound.longDesc "<p>Nid yw'r porwr yn gallu canfod y gweinydd gwestai ar gyfer y cyfeiriad yma.</p><ul><li>A wnaethoch gamgymeriad wrth deipio'r cyfeiriad? (e.e. <q><strong>ww</strong>.mozilla.org</q> yn lle <q><strong>www</strong>.mozilla.org</q>)</li><li>Ydych chi'n siŵr fod yr enw parth yn bodoli?   Efallai bod ei gofrestriad wedi dod i ben.</li><li>Ydych chi'n methu pori i wefannau eraill?   Gwiriwch eich cysylltiad rhwydwaith a gweinydd DNS.</li><li>A yw eich cyfrifiadur wedi ei amddiffyn gyda mur cadarn a dirprwy?  Gall gosodiadau anghywir ymyrryd â phori'r We.</li></ul>">
+
+<!ENTITY fileNotFound.title "Heb Ganfod Ffeil">
+<!ENTITY fileNotFound.longDesc "<ul><li>Efallai bod yr eitem wedi cael ei hailenwi, ei thynnu neu ei symud?</li><li>Oes yna wall sillafu, llythrennu neu wall teipio arall yn y cyfeiriad?</li><li>A oes gennych hawl digonol i gael mynediad at yr eitem hon?</li></ul>">
+
+<!ENTITY fileAccessDenied.title "Mae mynediad i'r ffeil wedi ei wrthod">
+<!ENTITY fileAccessDenied.longDesc "<ul><li>Gall ei fod wedi ei dynnu, symud neu fod caniatâd ffeiliau yn rhwystro mynediad.</li></ul>">
+
+<!ENTITY generic.title "Methu Cyflawni'r Cais">
+<!ENTITY generic.longDesc "<p>Nid oes gwybodaeth ar gael am y gwall neu broblem yma ar hyn o bryd.</p>">
+
+<!ENTITY malformedURI.title "Cyfeiriad Annilys">
+<!ENTITY malformedURI.longDesc "<p>Nid yw'r cyfeiriad yma mewn fformat adnabyddus. Gwiriwch y bar lleoliad a cheisiwch eto.</p>">
+
+<!ENTITY netInterrupt.title "Tarfu ar Drosglwyddo Data">
+<!ENTITY netInterrupt.longDesc "<p>Mae'r porwr wedi cysylltu'n llwyddiannus, ond cafodd y cysylltiad ei darfu wrth drosglwyddo gwybodaeth.   Ceisiwch eto.</p><ul><li>Methu pori gwefannau eraill? Gwiriwch gysylltiad y cyfrifiadur â'r rhwydwaith.</li><li>Yn dal i gael trwbl? Cysylltwch â'ch gweinyddwr rhwydwaith neu ddarparwr Rhyngrwyd am gymorth.</li></ul>">
+
+<!ENTITY notCached.title "Daeth y Ddogfen i Ben">
+<!ENTITY notCached.longDesc "<p>Nid yw'r ddogfen hon ar gael yn storfa dros dro'r porwr.</p><ul><li>Fel modd i ddiogelu nid yw'r porwr yn gofyn eto yn awtomatig am ddogfennau sensitif.</li><li>Cliciwch Ceisiwch Eto i ofyn eto am y ddogfen gan y wefan.</li></ul>">
+
+<!ENTITY netOffline.title "Modd All-lein">
+<!ENTITY netOffline.longDesc2 "<p>Mae&apos;r porwr yn gweithredu mewn modd all-lein ac nid oes modd cysylltu â&apos;r eitem hon.</p><ul><li>A yw&apos;r cyfrifiadur wedi cysylltu i rwydwaith fyw?</li><li>Cliciwch &quot;Ceisiwch Eto&quot; er mwyn newid i&apos;r modd ar-lein ac ail lwytho&apos;r dudalen.</li></ul>">
+
+<!ENTITY contentEncodingError.title "Gwall Amgodio Cynnwys">
+<!ENTITY contentEncodingError.longDesc "<p>Nid oes modd dangos y dudalen hon am ei bod yn defnyddio ffurf o gywasgiad sy'n anhysbys neu sydd ddim yn cael ei gynnal o .</p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY unsafeContentType.title "Math Anniogel o Ffeil">
+<!ENTITY unsafeContentType.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY netReset.title "Tarfu ar y Cyswllt">
+<!ENTITY netReset.longDesc "<p>Cafodd y cysylltiad rhwydwaith ei dorri wrth negydu cysylltiad. Ceisiwch eto.</p>">
+
+<!ENTITY netTimeout.title "Amser Allan y Rhwydwaith">
+<!ENTITY netTimeout.longDesc "<p>Nid yw'r wefan wedi ymateb i gais am gyswllt ac mae'r porwr wedi peidio aros am ateb.</p><ul><li>Gall fod y gweinydd yn profi galw uchel neu ataliad dros dro?  Ceisiwch eto.</li><li>A ydych yn methu pori i wefannau eraill? Gwiriwch gysylltiad rhwydwaith y cyfrifiadur.</li><li>A yw eich cyfrifiadur wedi ei ddiogelu gan fur cadarn neu ddirprwy?  Gall osodiadau anghywir effeithio ar bori'r we.</li><li>Dal yn cael problemau? Cysylltwch â'ch gweinyddwr rhwydwaith neu ddarparwr rhyngrwyd am gymorth.</li></ul>">
+
+<!ENTITY unknownProtocolFound.title "Protocol Anhysbys">
+<!ENTITY unknownProtocolFound.longDesc "<p>Mae'r cyfeiriad yn pennu protocol (e.e. <q>wxyz://</q>) nad yw'r porwr yn ei adnabod, felly nid yw'r porwr yn gallu cysylltu'n iawn â'r wefan.</p><ul><li>Ydych chi'n ceisio cael mynediad at wasanaethau aml-gyfrwng neu destun yn unig? Gwiriwch y wefan am yr anghenion ychwanegol hyn.</li><li>Mae rhai protocolau angen meddalwedd trydydd parti neu ategion cyn bod modd i'r porwr eu hadnabod.</li></ul>">
+
+<!ENTITY proxyConnectFailure.title "Gwrthododd y Gweinydd Dirprwyo'r cysylltiad">
+<!ENTITY proxyConnectFailure.longDesc "<p>Mae'r porwr wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy, ond mae'r dirprwy wedi gwrthod cysylltiad.</p><ul><li>A yw ffurfweddiad dirprwy'r porwr yn gywir? Gwiriwch y gosodiadau a cheisio eto.</li><li>A yw'r gwasanaeth dirprwy yn caniatáu cysylltiadau o'r rhwydwaith?</li><li>Dal yn cael problemau? Cysylltwch â'ch gweinyddwr rhwydwaith neu ddarparwr rhyngrwyd am gymorth.</li></ul>">
+
+<!ENTITY proxyResolveFailure.title "Heb ganfod y Gweinydd Dirprwyol">
+<!ENTITY proxyResolveFailure.longDesc "<p>Mae'r porwr wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy, ond nid oes modd canfod y dirprwy.</p><ul><li>A yw ffurfweddiad dirprwy'r porwr yn gywir? Gwiriwch y gosodiadau a cheisio eto.</li><li>A yw'r gwasanaeth dirprwy yn caniatáu cysylltiadau o'r rhwydwaith?</li><li>Dal yn cael problemau? Cysylltwch â'ch gweinyddwr rhwydwaith neu ddarparwr rhyngrwyd am gymorth.</li></ul>">
+
+<!ENTITY redirectLoop.title "Cylch Ailgyfeirio">
+<!ENTITY redirectLoop.longDesc "<p>Mae'r porwr wedi peidio ceisio estyn yr eitem. Mae'r safle'n ailgyfeirio'r cais mewn ffordd na fydd yn cael ei gwblhau.</p><ul><li>A ydych wedi analluogi neu rwystro cwcis angenrheidiol y wefan?</li><li><em>NODYN</em>: Os nad yw derbyn cwcis y safle'n datrys y broblem, mae'n debygol o fod yn fater ffurfweddiad y gweinydd ac nid eich cyfrifiadur.</li></ul>">
+
+<!ENTITY unknownSocketType.title "Ymateb Anghywir">
+<!ENTITY unknownSocketType.longDesc "<p>Ymatebodd y wefan i'r cais rhwydwaith mewn ffordd annisgwyl ac nid yw'r porwr yn gallu parhau.</p>">
+
+<!ENTITY nssFailure2.title "Methodd Cysylltiad Diogel">
+<!ENTITY nssFailure2.longDesc2 "<p>Nid oes modd dangos y dudalen rydych yn ceisio ei darllen gan nad oes modd gwirio dilysrwydd y data derbyniwyd.</p><ul><li>Cysylltwch â pherchennog y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY nssBadCert.title "Methodd Cysylltiad Diogel">
+<!ENTITY nssBadCert.longDesc2 "<ul> <li>Gall hyn fod yn anhawster gyda ffurfweddiad y gweinydd, neu gall fod bod rhywun yn ceisio ffugio'r gweinydd.</li> <li>Os ydych wedi cysylltu'n llwyddiannus a'r gweinydd yn y gorffennol, efallai mai gwall dros dro ydyw a gallwch geisio eto yn hwyrach.</li> </ul>">
+
+<!ENTITY securityOverride.linkText "Neu mae modd ychwanegu eithriad…">
+<!ENTITY securityOverride.warningContent "<p>Ni ddylech ychwanegu eithriad os ydych yn defnyddio cyswllt gwe nad ydych yn ymddiried yn llwyr ynddo neu os nad ydych wedi arfer a gweld negeseuon rhybudd ar gyfer y gweinydd hwn.</p> <p>Os ydych yn parhau i fod yn awyddus i ychwanegu eithriad i'r wefan, gallwch wneud hynny yng ngosodiadau uwch amgryptio.</p>">
+
+<!ENTITY cspBlocked.title "Rhwystrwyd gan Bolisi Diogelwch Cynnwys">
+<!ENTITY cspBlocked.longDesc "<p>Mae'r porwr wedi atal y dudalen rhag cael ei llwytho yn y ffordd yma gan fod gan y dudalen bolisi diogelwch cynnwys sy'n atal hynny.</p>">
+
+<!ENTITY xfoBlocked.title "Wedi'i rwystro gan Bolisi X-Frame-Options">
+<!ENTITY xfoBlocked.longDesc "<p>Ataliodd y porwr y dudalen hon rhag llwytho yn y cyd-destun hwn oherwydd bod gan y dudalen bolisi X-Frame-Options sy'n ei gwrthod.</p>">
+
+<!ENTITY corruptedContentErrorv2.title "Gwall Cynnwys Llygredig">
+<!ENTITY corruptedContentErrorv2.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio ei gweld yn sgil canfod gwall trosglwyddo data.</p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY remoteXUL.title "XUL pell">
+<!ENTITY remoteXUL.longDesc "<p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu am y broblem..</li></ul></p>">
+
+<!ENTITY inadequateSecurityError.title "Nid yw eich cysylltiad yn ddiogel">
+<!-- LOCALIZATION NOTE (inadequateSecurityError.longDesc) - Do not translate
+     "NS_ERROR_NET_INADEQUATE_SECURITY". -->
+<!ENTITY inadequateSecurityError.longDesc "Mae <p><span class='hostname'></span> yn defnyddio technoleg diogelwch sy'n hen ac yn agored i ymosodiad. Gall yr ymosodwr weld manylion am hyn roeddech yn meddwl ei fod yn ddiogel. Mae angen i weinyddwr y wefan drwsio'r gweinydd yn gyntaf cyn bod modd i chi ymweld â' r wefan.</p><p>Cod gwall: NS_ERROR_NET_INADEQUATE_SECURITY</p>">
+
+<!ENTITY blockedByPolicy.title "Tudalen wedi'i Rhwystro">
+
+<!ENTITY networkProtocolError.title "Gwall Protocol Rhwydwaith">
+<!ENTITY networkProtocolError.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio'i gweld oherwydd canfuwyd gwall yn y protocol rhwydwaith.</p><ul><li> Cysylltwch â pherchenogion y wefan i roi gwybod iddynt am y broblem hon.</li></ul>">
diff --git a/l10n-cy/dom/chrome/netErrorApp.dtd b/l10n-cy/dom/chrome/netErrorApp.dtd
new file mode 100644
index 0000000000..d245555380
--- /dev/null
+++ b/l10n-cy/dom/chrome/netErrorApp.dtd
@@ -0,0 +1,23 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- This file exists to allow applications to override one or more messages
+     from netError.dtd; Applications which want to do this should override
+     this file with their own version of netErrorApp.dtd -->
+
+<!-- An example (from Firefox):
+
+<!ENTITY securityOverride.linkText "Or you can add an exception…">
+<!ENTITY securityOverride.getMeOutOfHereButton "Get me out of here!">
+<!ENTITY securityOverride.exceptionButtonLabel "Add Exception…">
+
+<!ENTITY securityOverride.warningContent "
+<p>You should not add an exception if you are using an internet connection that you do not trust completely or if you are not used to seeing a warning for this server.</p>
+<p>If you still wish to add an exception for this site, you can do so in your advanced encryption settings.</p>
+
+<button id='getMeOutOfHereButton'>&securityOverride.getMeOutOfHereButton;</button>
+<button id='exceptionDialogButton'>&securityOverride.exceptionButtonLabel;</button>
+">
+
+-->
diff --git a/l10n-cy/dom/chrome/nsWebBrowserPersist.properties b/l10n-cy/dom/chrome/nsWebBrowserPersist.properties
new file mode 100644
index 0000000000..c7c0899fd7
--- /dev/null
+++ b/l10n-cy/dom/chrome/nsWebBrowserPersist.properties
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+readError=Methu cadw %S gan nad oedd modd darllen y ffeil ffynhonnell.\n\nCeisiwch eto neu cysylltwch â gweinyddwr eich system.
+writeError=Methu cadw %S, digwyddodd gwall anhysbys.\n\nCadwch i leoliad arall.
+launchError=Methu agor %S, digwyddodd gwall anhysbys.\n\nCadwch i ddisg yn gyntaf ac yna agor y ffeil.
+diskFull=Nid oes digon o le ar y ddisg i gadw %S.\n\nTynnwch ffeiliau diangen a ceisio eto, neu gadw mewn lleoliad gwahanol.
+readOnly=Methu cadw %S, gan fod y ddisg, ffolder neu ffeil wedi ei ddiogelu rhag ysgrifennu.\n\nGalluogwch ysgrifennu i'r ddisg a cheisio eto neu ei gadw i leoliad gwahanol.
+accessError=Methu cadw %S am nad oes modd newid cynnwys y ffolder.\n\nNewidiwch priodweddau'r ffolder a cheisio eto neu ei chadw i leoliad gwahanol.
+SDAccessErrorCardReadOnly=Methu llwytho'r ffeil i awr gan fod y cerdyn SD yn cael ei ddefnyddio.
+SDAccessErrorCardMissing=Methu llwytho'r ffeil i awr gan fod y cerdyn SD ar goll.
+helperAppNotFound=Methu agor %S am nad yw'r rhaglen gynorthwyol gysylltiedig yn bodoli. Newidiwch y cysylltiad yn eich dewisiadau.
+noMemory=Nid oes digon o gof i gyflawni'r weithred hon.\n\nCaewch rhai rhaglenni a cheisio eton.
+title=Llwytho %S i Lawr
+fileAlreadyExistsError=Methwyd cadw %S, gan fod ffeil yn bodoli eisoes gyda'r un enw â'r cyfeiriadur '_files'.\n\nCeisiwch gadw i leoliad arall.
+fileNameTooLongError=Methu cadw %S gan fod yr enw ffeil yn rhy hir.\n\nCeisiwch ei chadw gydag enw ffeil byrrach.
diff --git a/l10n-cy/dom/chrome/plugins.properties b/l10n-cy/dom/chrome/plugins.properties
new file mode 100644
index 0000000000..8191f7b2f4
--- /dev/null
+++ b/l10n-cy/dom/chrome/plugins.properties
@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+#    Those strings are inserted into an HTML page, so all HTML characters
+#    have to be escaped in a way that they show up correctly in HTML!
+
+# GMP Plugins
+gmp_license_info=Manylion trwyddedu
+gmp_privacy_info=Manylion Preifatrwydd
+
+openH264_name=OpenH264 Video Codec wedi ei ddarparu gan Cisco Systems, Inc.
+openH264_description2=Mae'r ategyn hwn yn cael ei osod yn awtomatig gan Mozilla er mwyn cyd-fynd â manyleb y WebRTC ac i alluogi galwadau WebRTC gyda dyfeisiau sydd angen y codec fideo H.264. Ewch i http://www.openh264.org/ i weld y cod ffynhonnell a dysgu rhagor am ei ddefnyddio.
+
+cdm_description2=Mae'r ategyn hwn yn galluogi chwarae cyfryngau amgryptiedig yn unol â manyleb Estyniadau Cyfryngau Amgryptiedig. Fel rheol defnyddir cyfryngau wedi'i amgryptio gan wefannau i ddiogelu rhag copïo cynnwys cyfryngau premiwm. Ewch i https://www.w3.org/TR/encrypted-media/ am fwy o wybodaeth ar Estyniadau Cyfryngau Amgryptiedig.
+
+widevine_description=Mae'r Widevine Content Decryption Module wedi ei ddarparu gan Google Inc.
diff --git a/l10n-cy/dom/chrome/security/caps.properties b/l10n-cy/dom/chrome/security/caps.properties
new file mode 100644
index 0000000000..19e76d5c97
--- /dev/null
+++ b/l10n-cy/dom/chrome/security/caps.properties
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+CheckLoadURIError = Gwall Diogelwch: Efallai na fydd cynnwys %S yn llwytho na chysylltu â %S.
+CheckSameOriginError = Gwall Diogelwch: Efallai na fydd cynnwys %S yn llwytho data o %S.
+ExternalDataError = Gwall Diogelwch: Ceisiodd cynnwys yn %S lwytho %S, ond nid yw'n cael llwytho data allanol wrth gael ei ddefnyddio fel delwedd.\u0020 
+
+CreateWrapperDenied = Gwrthodwyd caniatâd i greu amlapiwr i wrthrych dosbarth %S
+CreateWrapperDeniedForOrigin = Gwrthodwyd caniatâd i <%2$S> greu amlapiwr i wrthrych dosbarth %1$S
diff --git a/l10n-cy/dom/chrome/security/csp.properties b/l10n-cy/dom/chrome/security/csp.properties
new file mode 100644
index 0000000000..efca43a093
--- /dev/null
+++ b/l10n-cy/dom/chrome/security/csp.properties
@@ -0,0 +1,107 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# CSP Warnings:
+# LOCALIZATION NOTE (CSPViolation):
+# %1$S is the reason why the resource has not been loaded.
+CSPViolation = Mae gosodiadau'r dudalen wedi rhwystro llwytho adnodd: %1$S
+# LOCALIZATION NOTE (CSPViolationWithURI):
+# %1$S is the directive that has been violated.
+# %2$S is the URI of the resource which violated the directive.
+CSPViolationWithURI = Mae gosodiadau'r dudalen wedi rhwystro llwytho adnodd yn %2$S ("%1$S").
+# LOCALIZATION NOTE (CSPROViolation):
+# %1$S is the reason why the resource has not been loaded.
+CSPROViolation = Digwyddodd trosedd o bolisi adrodd yn unig CSP ("%1$S"). Caniatawyd yr ymddygiad a chafodd adroddiad CSP ei hanfon.
+# LOCALIZATION NOTE (CSPROViolationWithURI):
+# %1$S is the directive that has been violated.
+# %2$S is the URI of the resource which violated the directive.
+CSPROViolationWithURI = Gwelodd gosodiadau'r dudalen lwytho adnodd yn %2$S ("%1$S"). Mae adroddiad CSP yn cael ei hanfon.
+# LOCALIZATION NOTE (triedToSendReport):
+# %1$S is the URI we attempted to send a report to.
+triedToSendReport = Wedi ceisio anfon adroddiad at URI annilys: "%1$S"
+# LOCALIZATION NOTE (couldNotParseReportURI):
+# %1$S is the report URI that could not be parsed
+couldNotParseReportURI = methu didoli adroddiad URI: %1$S
+# LOCALIZATION NOTE (couldNotProcessUnknownDirective):
+# %1$S is the unknown directive
+couldNotProcessUnknownDirective = Methu prosesu cyfarwyddeb anhysbys '%1$S'
+# LOCALIZATION NOTE (ignoringUnknownOption):
+# %1$S is the option that could not be understood
+ignoringUnknownOption = Anwybyddu dewis anhysbys %1$S
+# LOCALIZATION NOTE (ignoringDuplicateSrc):
+# %1$S defines the duplicate src
+ignoringDuplicateSrc = Anwybyddu ffynhonnell dyblyg %1$S
+# LOCALIZATION NOTE (ignoringSrcFromMetaCSP):
+# %1$S defines the ignored src
+ignoringSrcFromMetaCSP = Anwybyddu ffynhonnell '%1$S' (Heb ei gynnal wrth ei ddarparu drwy elfen meta).
+# LOCALIZATION NOTE (ignoringSrcWithinScriptStyleSrc):
+# %1$S is the ignored src
+# script-src and style-src are directive names and should not be localized
+ignoringSrcWithinScriptStyleSrc = Anwybyddu "%1$S" o ffewn script-src: nonce-source neu hash-source penodol
+# LOCALIZATION NOTE (ignoringSrcForStrictDynamic):
+# %1$S is the ignored src
+# script-src, as well as 'strict-dynamic' should not be localized
+ignoringSrcForStrictDynamic = Anwybyddu “%1$S” o fewn script-src: ‘strict-dynamic’ wedi ei bennu
+# LOCALIZATION NOTE (ignoringStrictDynamic):
+# %1$S is the ignored src
+ignoringStrictDynamic = Anwybyddu ffynhonnell “%1$S” (Dim ond yn cael ei gynnal o fewn script-src).\u0020 
+# LOCALIZATION NOTE (strictDynamicButNoHashOrNonce):
+# %1$S is the csp directive that contains 'strict-dynamic'
+# 'strict-dynamic' should not be localized
+strictDynamicButNoHashOrNonce = Gall allweddair ‘strict-dynamic’ o fewn “%1$S” gyda dim nonce dilys na hash rwystro pob sgript rhag llwytho
+# LOCALIZATION NOTE (reportURInotHttpsOrHttp2):
+# %1$S is the ETLD of the report URI that is not HTTP or HTTPS
+reportURInotHttpsOrHttp2 = Dylai URI adroddiad (%1$S) fod yn URI HTTP neu HTTPS.
+# LOCALIZATION NOTE (reportURInotInReportOnlyHeader):
+# %1$S is the ETLD of the page with the policy
+reportURInotInReportOnlyHeader = Mae gan y wefan (%1$S) bolisi Adrodd yn Unig heb adroddiad URI. Ni fydd CSP yn rhwystro ac nid oes modd iddo adrodd ar dorri'r polisi.
+# LOCALIZATION NOTE (failedToParseUnrecognizedSource):
+# %1$S is the CSP Source that could not be parsed
+failedToParseUnrecognizedSource = Methwyd didoli ffynhonnell anadnabyddus %1$S
+# LOCALIZATION NOTE (upgradeInsecureRequest):
+# %1$S is the URL of the upgraded request; %2$S is the upgraded scheme.
+upgradeInsecureRequest = Diweddaru cais anniogel ‘%1$S’ i ddefnyddio ‘%2$S’
+# LOCALIZATION NOTE (ignoreSrcForDirective):
+ignoreSrcForDirective = Anwybyddu scs ar gyfer cyfarwyddid '%1$S'
+# LOCALIZATION NOTE (hostNameMightBeKeyword):
+# %1$S is the hostname in question and %2$S is the keyword
+hostNameMightBeKeyword = Dehongli %1$S fel enw gwesteiwr, nid allweddair. Os oeddech yn bwriadu iddo fod yn allweddair, defnyddiwch '%2$S' (wedi ei lapio mewn dyfynodau sengl).
+# LOCALIZATION NOTE (notSupportingDirective):
+# directive is not supported (e.g. 'reflected-xss')
+notSupportingDirective = Nid yw'n cynnal cyfarwyddeb '%1$S'. Bydd y cyfarwyddeb a gwerthoedd yn cael eu hanwybyddu.
+# LOCALIZATION NOTE (blockAllMixedContent):
+# %1$S is the URL of the blocked resource load.
+blockAllMixedContent = Rhwystro cais anniogel '%1$S'.
+# LOCALIZATION NOTE (ignoringDirectiveWithNoValues):
+# %1$S is the name of a CSP directive that requires additional values 
+ignoringDirectiveWithNoValues = Anwybyddu ‘%1$S‘ gan nad yw'n cynnwys unrhyw baramedrau.
+# LOCALIZATION NOTE (ignoringReportOnlyDirective):
+# %1$S is the directive that is ignored in report-only mode.
+ignoringReportOnlyDirective = Anwybyddu cyfarwyddeb blwch tywod pan y'i anfonwyd mewn polisi adrodd yn unig ‘%1$S’
+# LOCALIZATION NOTE (IgnoringSrcBecauseOfDirective):
+# %1$S is the name of the src that is ignored.
+# %2$S is the name of the directive that causes the src to be ignored.
+IgnoringSrcBecauseOfDirective=Anwybyddu ‘%1$S’ oherwydd cyfarwyddeb ‘%2$S’.
+
+# LOCALIZATION NOTE (IgnoringSourceWithinDirective):
+# %1$S is the ignored src
+# %2$S is the directive  which supports src
+IgnoringSourceWithinDirective = Anwybyddu ffynhonnell “%1$S” (Dim ond yn cael ei gynnal o fewn ‘%2$S’).
+ 
+# CSP Errors:
+# LOCALIZATION NOTE (couldntParseInvalidSource):
+# %1$S is the source that could not be parsed
+couldntParseInvalidSource = Methu didoli ffynhonnell annilys %1$S
+# LOCALIZATION NOTE (couldntParseInvalidHost):
+# %1$S is the host that's invalid
+couldntParseInvalidHost = Methwyd didoli gwestai annilys %1$S
+# LOCALIZATION NOTE (couldntParsePort):
+# %1$S is the string source
+couldntParsePort = Methu didoli porth yn %1$S
+# LOCALIZATION NOTE (duplicateDirective):
+# %1$S is the name of the duplicate directive
+duplicateDirective = Mae cyfarwyddebau %1$S dyblyg wedi eu canfod.  Bydd yr holl rhai heblaw'r cyntaf yn cael eu hanwybyddu.
+# LOCALIZATION NOTE (couldntParseInvalidSandboxFlag):
+# %1$S is the option that could not be understood
+couldntParseInvalidSandboxFlag = Methu didoli baner blwch tywod annilys ‘%1$S’
diff --git a/l10n-cy/dom/chrome/security/security.properties b/l10n-cy/dom/chrome/security/security.properties
new file mode 100644
index 0000000000..bbc413e490
--- /dev/null
+++ b/l10n-cy/dom/chrome/security/security.properties
@@ -0,0 +1,154 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Mixed Content Blocker
+# LOCALIZATION NOTE: "%1$S" is the URI of the blocked mixed content resource
+BlockMixedDisplayContent = Rhwystrwyd llwytho cynnwys arddangos cymysg "%1$S"
+BlockMixedActiveContent = Rhwystrwyd llwytho cynnwys gweithredol cymysg "%1$S"
+
+# CORS
+# LOCALIZATION NOTE: Do not translate "Access-Control-Allow-Origin", Access-Control-Allow-Credentials, Access-Control-Allow-Methods, Access-Control-Allow-Headers
+CORSDisabled=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: CORS wedi ei analluogi).
+CORSDidNotSucceed=Cais Traws Darddiad wedi ei Rwystro: Mae'r Un Polisi Tarddiad yn analluogi darllen yr adnodd pell yn %1$S. (Rheswm: methodd cais CORS).
+CORSOriginHeaderNotAdded=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: Pennyn CORS ‘Origin’ wedi methu cael ei ychwanegu).
+CORSExternalRedirectNotAllowed=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: cais ailgyfeirio allanol CORS heb ei ganiatâu).
+CORSRequestNotHttp=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: cais CORS nid http).
+CORSMissingAllowOrigin=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: pennyn CORS coll 'Access-Control-Allow-Origin' ).
+CORSMultipleAllowOriginNotAllowed=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: CORS 'Access-Control-Allow-Origin' lluosog ddim yn cael eu caniatáu ).
+CORSAllowOriginNotMatchingOrigin=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: pennyn CORS 'Access-Control-Allow-Origin' ddim yn cydweddu %2$S ).
+CORSNotSupportingCredentials=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: Nid yw'r cyflwyniad yn cael ei gynnal ym mhennyn 'Access-Control-Allow-Credentials' CORS os y pennyn yw ‘*’).
+CORSMethodNotFound=Rhwystrwyd Cais Croes Darddiad: Mae'r Polisi Un Tarddiad yn atal darllen yr adnodd pell yn %1$S. (Rheswm: methu canfod dull ym mhennyn CORS 'Access-Control-Allow-Methods' ).
+CORSMissingAllowCredentials=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: wedi disgwyl 'true' ym mhennyn 'Access-Control-Allow-Credentials' CORS ).
+CORSPreflightDidNotSucceed2=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: methodd ymateb cyn esgyn CORS).
+CORSInvalidAllowMethod=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: tocyn annilys '%2$S' ym mhennyn 'Access-Control-Allow-Methods' CORS ).
+CORSInvalidAllowHeader=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: tocyn annilys '%2$S' ym mhennyn 'Access-Control-Allow-Headers' CORS ).
+CORSMissingAllowHeaderFromPreflight2=Rhwystrwyd Cais Croes-Tarddiad: Mae'r Polisi Un Tarddiad yn rhwystro darllen yr adnodd pell yn %1$S. (Rheswm: nid oes hawl i bennyn ‘%2$S’ yn ôl pennyn 'Access-Control-Allow-Headers' sianel cyn ehedeg CORS).
+
+# LOCALIZATION NOTE: Do not translate "Strict-Transport-Security", "HSTS", "max-age" or "includeSubDomains"
+STSUnknownError=Strict-Transport-Security: Digwyddodd gwall anhysbys wrth brosesu'r pennyn dynodwyd gan y wefan.
+STSUntrustworthyConnection=Strict-Transport-Security: Mae'r cysylltiad i'r wefan yn anibynadwy, felly anwybyddwyd y pennyn hwn.
+STSCouldNotParseHeader=Strict-Transport-Security: Pennodd y wefan bennyn nad oedd modd ei didoli yn llwyddiannus.
+STSNoMaxAge=Strict-Transport-Security: Pennodd y wefan bennyn nad oedd yn cynnwys cyfarwyddid 'max-age'.
+STSMultipleMaxAges=Strict-Transport-Security: Pennodd y wefan bennyn oedd yn cynnwys cyfarwyddiadau 'max-age' lluosog.
+STSInvalidMaxAge=Strict-Transport-Security: Pennodd y wefan bennyn oedd yn cynnwys cyfarwyddid 'max-age' annilys.
+STSMultipleIncludeSubdomains=Strict-Transport-Security: Pennodd y pennyn oedd y cynnwys cyfarwyddiadau 'includeSubDomains' lluosog.
+STSInvalidIncludeSubdomains=Strict-Transport-Security: Pennodd y wefan bennyn oedd yn cynnwys cyfarwyddid 'includeSubDomains' annilys.
+STSCouldNotSaveState=Strict-Transport-Security: Digwyddodd gwall yn nodi'r wefan fel gwestai Strict-Transport-Security.
+
+# LOCALIZATION NOTE: Do not translate "SHA-1"
+SHA1Sig=Mae'r wefan yn defnyddio Tystysgrif SHA-1; argymhellir eich bod yn defnyddio tystysgrif sydd ag algorithm llofnod sy'n defnyddio swyddogaethau hash cryfach na SHA-1.
+InsecurePasswordsPresentOnPage=Mae'r meysydd cyfrinair yn cyflwyno tudalen anniogel (http://). Mae hyn yn berygl diogelwch sy'n caniatáu i fanylion mewngofnodi defnyddiwr gael ei ddwyn.
+InsecureFormActionPasswordsPresent=Mae'r meysydd cyfrinair yn cyflwyno gweithredu ffurflen (http://) anniogel. Mae hyn yn berygl diogelwch sy'n caniatáu i fanylion mewngofnodi defnyddiwr gael ei ddwyn.
+InsecurePasswordsPresentOnIframe=Mae'r meysydd cyfrinair yn cyflwyno iframe (http://) anniogel. Mae hyn yn berygl diogelwch sy'n caniatáu i fanylion mewngofnodi defnyddiwr gael ei ddwyn.
+# LOCALIZATION NOTE: "%1$S" is the URI of the insecure mixed content resource
+LoadingMixedActiveContent2=Llwytho cynnwys gweithredol (anniogel) cymysg ar dudalen diogel "%1$S"
+LoadingMixedDisplayContent2=Llwytho cynnwys gweithredol (anniogel) cymysg dangos ar dudalen diogel "%1$S"
+LoadingMixedDisplayObjectSubrequestDeprecation=Ni ddylid annog llwytho cynnwys cymysg (anniogel) “%1$S” o fewn ategyn ar dudalen ddiogel a bydd yn cael ei rwystro cyn bo hir.
+# LOCALIZATION NOTE: "%S" is the URI of the insecure mixed content download
+MixedContentBlockedDownload = Wedi rhwystro llwytho cynnwys anniogel “%S”.
+
+# LOCALIZATION NOTE: Do not translate "allow-scripts", "allow-same-origin", "sandbox" or "iframe"
+BothAllowScriptsAndSameOriginPresent=Mae modd i iframe sydd ag allow-scripts ac allow-same-origin i'w briodweddau sandbox fedru tynnu ei sandbox.
+
+# LOCALIZATION NOTE: Do not translate "allow-top-navigation-by-user-activation", "allow-top-navigation", "sandbox" or "iframe"
+BothAllowTopNavigationAndUserActivationPresent=Bydd iframe sydd â chaniatâd allow-top-navigation a chaniatáu-top-navigation-by-user-activation ar gyfer ei briodoledd blwch tywod yn caniatáu llywio uchaf.
+
+# Sub-Resource Integrity
+# LOCALIZATION NOTE: Do not translate "script" or "integrity". "%1$S" is the invalid token found in the attribute.
+MalformedIntegrityHash=Mae gan yr elfen script hash anffurfedig yn ei briodwedd integrity: "%1$S". Y fformat cywir yw "<hash algorithm>-<hash value>".
+# LOCALIZATION NOTE: Do not translate "integrity"
+InvalidIntegrityLength=Mae'r hash sydd o fewn y briodwedd integrity o'r hyd anghywir.
+# LOCALIZATION NOTE: Do not translate "integrity"
+InvalidIntegrityBase64=Nid oedd modd dadgodio'r hash sydd o fewn y briodwedd integrity.
+# LOCALIZATION NOTE: Do not translate "integrity". "%1$S" is the type of hash algorithm in use (e.g. "sha256").
+IntegrityMismatch=Nid yw dim o'r hash "%1$S" yn y briodwedd integrity yn cydweddu a chynnwys yr is adnodd.
+# LOCALIZATION NOTE: "%1$S" is the URI of the sub-resource that cannot be protected using SRI.
+IneligibleResource=Nid yw'r "%1$S" yn agored ar gyfer gwiriadau cyfanrwydd gan nad yw wedi ei alluogi ar gyfer CORS nac yn same-origin.
+# LOCALIZATION NOTE: Do not translate "integrity". "%1$S" is the invalid hash algorithm found in the attribute.
+UnsupportedHashAlg=Algorithm hash heb ei gynnal yn y briodwedd integrity: "%1$S"
+# LOCALIZATION NOTE: Do not translate "integrity"
+NoValidMetadata=Nid yw'r briodwedd integrity yn cynnwys unrhyw metadata dilys.
+
+# LOCALIZATION NOTE: Do not translate "RC4".
+WeakCipherSuiteWarning=Mae'r wefan yn defnyddio seiffr RC4 ar gyfer amgryptiad, sy'n anghymeradwy ac anniogel.
+
+DeprecatedTLSVersion2=Mae'r wefan hon yn defnyddio fersiwn anghymeradwy o TLS. Uwchraddiwch i TLS 1.2 neu 1.3 os gwelwch yn dda.
+
+#XCTO: nosniff
+# LOCALIZATION NOTE: Do not translate "X-Content-Type-Options: nosniff".
+MimeTypeMismatch2=Cafodd yr adnodd o “%1$S” ei rwystro oherwydd gwrthdaro math MIME (“%2$S”) (X-Content-Type-Options: nosniff).
+# LOCALIZATION NOTE: Do not translate "X-Content-Type-Options" and also do not translate "nosniff".
+XCTOHeaderValueMissing=Rhybudd pennyn X-Content-Type-Options: y gwerth oedd “%1$S”; a oedd yn fwriad gennych i anfon “nosniff”?
+# LOCALIZATION NOTE: Do not translate "X-Content-Type-Options" and also do not translate "nosniff".
+XTCOWithMIMEValueMissing=Ni luniwyd yr adnodd o “%1$S” oherwydd math MIME anhysbys, anghywir neu ar goll (X-Content-Type-Options: nosniff).
+
+BlockScriptWithWrongMimeType2=Cafodd y sgript “%1$S” ei rwystro oherwydd math gwaharddedig o MIME (“%2$S”).
+WarnScriptWithWrongMimeType=Cafodd y sgript o “%1$S” ei llwytho er nad yw ei fath MIME (“%2$S”) yn fath MIME JavaScript dilys.
+# LOCALIZATION NOTE: Do not translate "importScripts()"
+BlockImportScriptsWithWrongMimeType=Cafodd y sgript “%1$S” gyda importScripts() ei rwystro oherwydd math gwaharddedig o MIME (“%2$S”).
+BlockWorkerWithWrongMimeType=Rhwystrwyd llwytho modiwl o “%1$S” oherwydd math MIME (“%2$S”) heb ei ganiatáu.
+BlockModuleWithWrongMimeType=Rhwystrwyd llwytho modiwl o “%1$S” ei rwystro oherwydd math MIME (“%2$S”).
+
+# LOCALIZATION NOTE: Do not translate "data: URI".
+BlockTopLevelDataURINavigation=Llywio i ddata ar y lefel uchaf: dim URI (Rhwystro llwytho: “%1$S”)
+BlockSubresourceRedirectToData=Ailgyfeirio i ddata anniogel: dim caniatâd ar gyfer URI (Wedi rhwystro llwytho: “%1$S”)
+
+BlockSubresourceFTP=Nid yw llwytho is adnodd FTP o fewn o fewn tudalen http(s) yn cael ei ganiatáu (Rhwystrwyd llwytho : “%1$S”)
+
+RestrictBrowserEvalUsage=Nid yw eval() a'r defnydd tebyg i eval yn cael eu caniatáu yn y Broses Rhiant nac mewn Cyd-destunau System (Defnydd wedi'i rwystro yn “%1$S”)
+
+# LOCALIZATION NOTE (BrowserUpgradeInsecureDisplayRequest):
+# %1$S is the browser name "brandShortName"; %2$S is the URL of the upgraded request; %1$S is the upgraded scheme.
+BrowserUpgradeInsecureDisplayRequest = Mae %1$S yn diweddaru cais dangos anniogel ‘%2$S’ i ddefnyddio ‘%3$S’
+
+# LOCALIZATION NOTE (MixedContentAutoUpgrade):
+# %1$S is the URL of the upgraded request; %2$S is the upgraded scheme.
+MixedContentAutoUpgrade=Diweddaru cais dangos anniogel ‘%1$S’ i ddefnyddio ‘%2$S’
+# LOCALIZATION NOTE (RunningClearSiteDataValue):
+# %S is the URI of the resource whose data was cleaned up
+RunningClearSiteDataValue=Pennyn Clear-Site-Data wedi gorfodi glanhau data “%S”.
+UnknownClearSiteDataValue=Wedi canfod pennyn Clear-Site-Data. Gwerth anhysbys “%S”.
+
+# Reporting API
+ReportingHeaderInvalidJSON=Pennawd Adrodd: gwerth JSON annilys wedi ei dderbyn.
+ReportingHeaderInvalidNameItem=Pennawd Adrodd: enw annilys ar gyfer grŵp.
+ReportingHeaderDuplicateGroup=Pennawd Adrodd: anwybyddu'r grŵp dyblyg o'r enw “%S”.
+ReportingHeaderInvalidItem=Pennawd Adrodd: anwybyddu eitem annilys o'r enw “%S”.
+ReportingHeaderInvalidEndpoint=Pennawd Adrodd: anwybyddu'r pwynt diwedd ar gyfer eitem o'r enw “%S”.
+# LOCALIZATION NOTE(ReportingHeaderInvalidURLEndpoint): %1$S is the invalid URL, %2$S is the group name
+ReportingHeaderInvalidURLEndpoint=Pennawd Adrodd: anwybyddu'r pwynt diwedd URL “%1$S” ar gyfer eitem o'r enw “%2$S”.
+
+FeaturePolicyUnsupportedFeatureName=Feature Policy: Hepgor enw nodwedd heb ei gynnal “%S”.
+# TODO: would be nice to add a link to the Feature-Policy MDN documentation here. See bug 1449501
+FeaturePolicyInvalidEmptyAllowValue= Feature Policy: Hepgor rhestr caniatáu gwag nodwedd: “%S”.
+# TODO: would be nice to add a link to the Feature-Policy MDN documentation here. See bug 1449501
+FeaturePolicyInvalidAllowValue=Feature Policy: Hepgor enw nodwedd heb ei gynnal “%S”.
+
+# LOCALIZATION NOTE: "%1$S" is the limitation length (bytes) of referrer URI, "%2$S" is the origin of the referrer URI.
+ReferrerLengthOverLimitation=Pennyn HTTP Cyfeiriwr: Mae hyd dros derfyn beitiau “%1$S” - tynnu pennyn cyfeiriwr i lawr i'r gwreiddiol: “%2$S”
+# LOCALIZATION NOTE: "%1$S" is the limitation length (bytes) of referrer URI, "%2$S" is the origin of the referrer URI.
+ReferrerOriginLengthOverLimitation=Pennyn HTTP Cyfeiriwr: Mae hyd y gwreiddiol o fewn y cyfeiriwr dros terfyn didau “%1$S” - tynnu'r cyfeiriwr gyda'r gwreiddiol: “%2$S”.
+
+# X-Frame-Options
+# LOCALIZATION NOTE(XFrameOptionsInvalid): %1$S is the header value, %2$S is frame URI. Do not translate "X-Frame-Options".
+XFrameOptionsInvalid = Cafwyd hyd i bennawd annilys X-Frame-Options wrth lwytho “%2$SS”: nid yw “%1$S” yn gyfarwyddeb ddilys.
+# LOCALIZATION NOTE(XFrameOptionsDeny): %1$S is the header value, %2$S is frame URI and %3$S is the parent document URI. Do not translate "X-Frame-Options".
+XFrameOptionsDeny=Mae llwytho “%2$S” mewn ffrâm yn cael ei wrthod gan gyfarwyddeb “X-Frame-Options” sydd wedi ei osod i “%1$S”.
+
+# HTTPS-Only Mode
+# LOCALIZATION NOTE: %1$S is the URL of the upgraded request; %2$S is the upgraded scheme.
+HTTPSOnlyUpgradeRequest = Uwchraddio cais ansicr %1$S” i ddefnyddio %2$S.
+# LOCALIZATION NOTE: %1$S is the URL of request.
+HTTPSOnlyNoUpgradeException = Peidio ag uwchraddio cais anniogel “%1$S”  oherwydd ei fod wedi'i eithrio.
+# LOCALIZATION NOTE: %1$S is the URL of the failed request; %2$S is an error-code.
+HTTPSOnlyFailedRequest = Methodd uwchraddio cais anniogel “%1$S”. (%2$S)
+
+# LOCALIZATION NOTE: %S is the URL of the blocked request;
+IframeSandboxBlockedDownload = Cafodd llwytho “%S” ei rwystro oherwydd bod gan yr iframe sbarduno faner y blwch tywod wedi'i osod.
+
+# Sanitizer API
+# LOCALIZATION NOTE: Please do not localize "DocumentFragment". It's the name of an API.
+SanitizerRcvdNoInput = Wedi derbyn mewnbwn gwag neu ddim mewnbwn. Dychwelyd DocumentFragment gwag.
+# LOCALIZATION NOTE: "Sanitizer" is the name of the API. Please do not localize.
+SanitizerOptionsDiscarded = Nid yw opsiynau ar gyfer yr adeiladwr Sanitizer yn cael eu cynnal eto. Sylwch mai ymddygiad arbrofol yw hwn.
diff --git a/l10n-cy/dom/chrome/svg/svg.properties b/l10n-cy/dom/chrome/svg/svg.properties
new file mode 100644
index 0000000000..b19914a1c7
--- /dev/null
+++ b/l10n-cy/dom/chrome/svg/svg.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+AttributeParseWarning=Gwerth annisgwyl %2$S yn didoli priodwedd %1$S.
diff --git a/l10n-cy/dom/chrome/xml/prettyprint.dtd b/l10n-cy/dom/chrome/xml/prettyprint.dtd
new file mode 100644
index 0000000000..00e64c0c61
--- /dev/null
+++ b/l10n-cy/dom/chrome/xml/prettyprint.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY xml.nostylesheet "Does gan y ffeil XML yma ddim nodweddion steil yn perthyn iddi. Mae'r goeden ddogfen i'w weld isod.">
diff --git a/l10n-cy/dom/chrome/xslt/xslt.properties b/l10n-cy/dom/chrome/xslt/xslt.properties
new file mode 100644
index 0000000000..30d2eea40d
--- /dev/null
+++ b/l10n-cy/dom/chrome/xslt/xslt.properties
@@ -0,0 +1,39 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+1  = Methodd didoli dalen steil XSLT.
+2  = Methodd didoli'r mynegiant XPath.
+3  = 
+4  = Methodd trawsffurfiad XSLT.
+5  = Swyddogaeth XSLT/XPath annilys.
+6  = Dalen steil XSLT Stylesheet yn ailadroddus (o bosibl).
+7  = Gwerth priodwedd anghyfreithlon yn XSLT 1.0.
+8  = Disgwyliwyd i fynegiad XPath ddychwelyd NodeSet.
+9  = Ataliwyd trawsffurfiad XSLT gan <xsl:message>.
+10 = Digwyddodd gwall rhwydwaith wrth lwytho dalen steil XSLT:
+11 = Nid oes gan ddalensteil XSLT mimetype XML:
+12 = Mae dalen steil XSLT ynmewnforio neu gynnwys ei hun yn uniongyrchol neu anuniongyrchol:
+13 = Galwyd swyddogaeth XPath gyda'r nifer anghywir o ymresymiadau.
+14 = Galwyd estyniad XPath anhysbys.
+15 = Methiant didoli XPath: disgwyl ')':
+16 = Methiant didoli XPath: echelin annilys:
+17 = Methiant didoli XPath: Disgwyl enw neu brawf Nodetype:
+18 = Methiant didoli XPath: disgwyl ']':
+19 = Methiant didoli XPath: amrywiolyn annilys:
+20 = Methiant didoli XPath: diwedd ymadrodd annisgwyl:
+21 = Methiant didoli XPath: disgwyl gweithredydd:
+22 = Methiant didoli XPath: llythrennydd heb ei gau:
+23 = Methiant didoli XPath ':' annisgwyl:
+24 = Methiant didoli XPath: '!' unexpected, negation is not():
+25 = Methiant didoli XPath: canfod nod anghyfreithlon:
+26 = Methiant didoli XPath: disgwyl gweithredydd deuaidd:
+27 = Cafodd dalen steil XSLT ei rwystro am resymau diogelwch.
+28 = Gwerthuso mynegiad annilys.
+29 = Angor crwm anghytbwys.
+30 = Creu elfen gyda QName annilys.
+31 = Rwymo amrywiol yn cysgodi rhwymo amrywiol o fewn yr un templed.
+32 = Nid oes caniatâd i alwad i'r swyddogaeth allweddol.
+
+LoadingError = Gwall llwytho dalen steil: %S
+TransformError = Gwall yn ystod trawsffurfiad XSLT: %S
diff --git a/l10n-cy/dom/dom/media.ftl b/l10n-cy/dom/dom/media.ftl
new file mode 100644
index 0000000000..82565edee0
--- /dev/null
+++ b/l10n-cy/dom/dom/media.ftl
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+mediastatus-fallback-title = Mae { -brand-short-name } yn chwarae cyfryngau
diff --git a/l10n-cy/editor/ui/chrome/composer/editingOverlay.dtd b/l10n-cy/editor/ui/chrome/composer/editingOverlay.dtd
new file mode 100644
index 0000000000..0e3c011366
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editingOverlay.dtd
@@ -0,0 +1,40 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- File menu items -->
+<!ENTITY openFileCmd.label "Agor Ffeil…">
+<!ENTITY openFileCmd.accesskey "A">
+<!ENTITY openFileCmd.key "O">
+<!ENTITY openRemoteCmd.label "Agor Lleoliad Gwe…">
+<!ENTITY openRemoteCmd.accesskey "L">
+<!ENTITY openRemoteCmd.key "L">
+<!ENTITY fileRecentMenu.label "Tudalennau Diweddar">
+<!ENTITY fileRecentMenu.accesskey "T">
+<!ENTITY saveCmd.label "Cadw">
+<!ENTITY saveCmd.accesskey "C">
+<!ENTITY saveAsCmd.label "Cadw Fel…">
+<!ENTITY saveAsCmd.accesskey "F">
+<!ENTITY saveAsChangeEncodingCmd2.label "Cadw a Newid Amgodiad Nod">
+<!ENTITY saveAsChangeEncodingCmd2.accesskey "N">
+<!ENTITY publishCmd.label "Cyhoeddi">
+<!ENTITY publishCmd.accesskey "y">
+<!ENTITY publishCmd.key "S">
+<!ENTITY publishAsCmd.label "Cyhoeddi Fel…">
+<!ENTITY publishAsCmd.accesskey "F">
+<!ENTITY fileRevert.label "Dychwelyd">
+<!ENTITY fileRevert.accesskey "D">
+
+<!-- Edit menu items -->
+<!ENTITY publishSettings.label "Gosodiadau'r Wefan Cyhoeddi…">
+<!ENTITY publishSettings.accesskey "G">
+
+<!-- Toolbar buttons/items -->
+<!ENTITY newToolbarCmd.label "Newydd">
+<!ENTITY newToolbarCmd.tooltip "Creu tudalen Cyfansoddwr newydd">
+<!ENTITY openToolbarCmd.label "Agor">
+<!ENTITY openToolbarCmd.tooltip "Agor ffeil leol">
+<!ENTITY saveToolbarCmd.tooltip "Cadw ffeil i leoliad lleol">
+<!ENTITY publishToolbarCmd.tooltip "Llwytho ffeil i fyny i leoliad pell">
+<!ENTITY printToolbarCmd.label "Argraffu">
+<!ENTITY printToolbarCmd.tooltip "Argraffu'r dudalen hon">
diff --git a/l10n-cy/editor/ui/chrome/composer/editor.dtd b/l10n-cy/editor/ui/chrome/composer/editor.dtd
new file mode 100644
index 0000000000..627a63b9a4
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editor.dtd
@@ -0,0 +1,67 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+<!-- LOCALIZATION NOTE  (editorWindow.titlemodifier): DONT_TRANSLATE -->
+
+<!ENTITY editorWindow.titlemodifier "Composer"> 
+<!ENTITY editorWindow.titlemodifiermenuseparator " - ">
+<!-- Menu items:  the . means that the menu item isn't implemented yet -->
+<!-- Toolbar-only items -->
+
+
+<!ENTITY compositionToolbar.tooltip "Bar Offer Ysgrifennu">
+<!ENTITY previewToolbarCmd.label "Pori">
+<!ENTITY previewToolbarCmd.tooltip "Llwytho'r dudalen yn y porwr">
+<!-- File menu items -->
+
+<!ENTITY exportToTextCmd.label "Allforio i Destun…">
+<!ENTITY exportToTextCmd.accesskey "D">
+<!ENTITY previewCmd.label "Pori'r Dudalen">
+<!ENTITY previewCmd.accesskey "P">
+<!ENTITY sendPageCmd.label "Anfon y Dudalen…">
+<!ENTITY sendPageCmd.accesskey "A">
+<!-- View menu items -->
+
+<!ENTITY compositionToolbarCmd.label "Bar Offer Ysgrifennu">
+<!ENTITY compositionToolbarCmd.accesskey "Y">
+<!ENTITY formattingToolbarCmd.label "Bar Offer Fformatio">
+<!ENTITY formattingToolbarCmd.accesskey "F">
+<!ENTITY editmodeToolbarCmd.label "Bar Offer Modd Golygu">
+<!ENTITY editmodeToolbarCmd.accesskey "M">
+<!-- Format menu items -->
+
+<!ENTITY formatMenu.label "Fformat">
+<!ENTITY formatMenu.accesskey "o">
+<!ENTITY grid.label "Grid lleoli">
+<!ENTITY grid.accesskey "G">
+<!ENTITY pageProperties.label "Teitl Tudalen a Phriodoleddau…">
+<!ENTITY pageProperties.accesskey "T">
+<!-- Tools menu items -->
+
+<!ENTITY validateCmd.label "Gwirio HTML">
+<!ENTITY validateCmd.accesskey "G">
+<!-- Display Mode toolbar and View menu items -->
+
+<!ENTITY NormalModeTab.label "Arferol">
+<!ENTITY NormalMode.label "Modd Golygu Arferol">
+<!ENTITY NormalMode.accesskey "A">
+<!ENTITY NormalMode.tooltip "Dangos borderi tabl ac angorau a enwyd">
+<!ENTITY AllTagsModeTab.label "Tagiau HTML">
+<!ENTITY AllTagsMode.label "Tagiau HTML">
+<!ENTITY AllTagsMode.accesskey "H">
+<!ENTITY AllTagsMode.tooltip "Dangos eiconau am bob tag HTML">
+<!-- LOCALIZATION NOTE: (HTMLSourceModeTab.dir, HTMLSourceModeTab.label)
+     Do NOT translate text for 'HTMLSourceModeTab.dir', use latin "ltr" if
+     you want the <html> image to left of the 'HTMLSourceModeTab.label' text,
+     or use latin "rtl" if you want this image to the right of text. You do
+     not need to include HTML in the label 'HTMLSourceModeTab.label' -->
+<!ENTITY HTMLSourceModeTab.dir "De i Chwith">
+<!ENTITY HTMLSourceModeTab.label "Cod gwreiddiol">
+<!ENTITY HTMLSourceMode.label "Cod Gwreiddiol HTML">
+<!ENTITY HTMLSourceMode.accesskey "C">
+<!ENTITY HTMLSourceMode.tooltip "Golygu Cod Gwreiddiol HTML">
+<!ENTITY PreviewModeTab.label "Rhagolwg">
+<!ENTITY PreviewMode.label "Rhagolwg">
+<!ENTITY PreviewMode.accesskey "R">
+<!ENTITY PreviewMode.tooltip "Dangos fel WYSWYG (Be ti'n gweld yw be ti'n cael - fel yn y porwr)">
diff --git a/l10n-cy/editor/ui/chrome/composer/editor.properties b/l10n-cy/editor/ui/chrome/composer/editor.properties
new file mode 100644
index 0000000000..62a5d47d26
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editor.properties
@@ -0,0 +1,208 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE FILE: embedded "\n" represent HTML breaks (<br>)
+# Don't translate embedded "\n".
+# Don't translate strings like this: %variable% 
+#  as they will be replaced using JavaScript
+#
+No=Na
+Save=Cadw
+More=Rhagor
+Less=Llai
+MoreProperties=Rhagor o Briodweddau
+FewerProperties=Llai o Briodweddau
+PropertiesAccessKey=P
+None=Dim
+none=dim
+OpenHTMLFile=Agor Ffeil HTML
+OpenTextFile=Agor Ffeil Testun
+SelectImageFile=Dewiswch Ffeil Delwedd
+SaveDocument=Cadw Tudalen
+SaveDocumentAs=Cadw Tudalen Fel
+SaveTextAs=Cadw Testun Fel
+EditMode=Modd Golygu
+Preview=Rhagolwg
+Publish=Cyhoeddi
+PublishPage=Cyhoeddi Tudalen
+DontPublish=Peidio Cyhoeddi
+SavePassword=Defnyddiwch y Rheolwr Cyfrinair i gadw'r cyfrinair
+CorrectSpelling=(sillafu cywir)
+NoSuggestedWords=(dim geiriau'n cael eu cynnig)
+NoMisspelledWord=Does dim geiriau wedi'u camsillafu
+CheckSpellingDone=Cwblhawyd gwirio'r sillafu.
+CheckSpelling=Gwirio Sillafu
+InputError=Gwall
+Alert=Rhybudd
+CantEditFramesetMsg=Nid yw'r golygydd yn gallu golygu fframsetiau HTML na thudalennau gyda fframiau mewnlin. Ar gyfer fframsetiau ceisiwch olygu'r dudalen ar gyfer pob ffrâm ar wahân. Am dudalennau gyda fframiau, cadwch gopi o'r dudalen a thynnu'r tag <iframe>.
+CantEditMimeTypeMsg=Does dim modd golygu'r math yma o dudalen.
+CantEditDocumentMsg=Does dim modd golygu'r dudalen am reswm anhysbys.
+BeforeClosing=cyn cau
+BeforePreview=cyn edrych arno yn y porwr
+BeforeValidate=cyn gwirio'r ddogfen
+# LOCALIZATION NOTE (SaveFilePrompt, PublishPrompt): Don't translate %title% and %reason% (this is the reason for asking user to close, such as "before closing")
+SaveFilePrompt=Cadw newidiadau i "%title%" %reason%?\u0020
+PublishPrompt=Cadw newidiadau i "%title%" %reason%?\u0020
+SaveFileFailed=Methwyd cadw'r ffeil!
+
+# Publishing error strings:
+# LOCALIZATION NOTE Don't translate %dir% or %file% in the Publishing error strings:
+FileNotFound=Heb ganfod %file%.
+SubdirDoesNotExist=Nid yw'r is-gyfeiriadur "%dir%" yn bodoli ar y safle hwn neu mae'r enw ffeil "%file%" yn cael ei ddefnyddio gan is-gyfeiriadur arall.
+FilenameIsSubdir=Mae'r enw ffeil "%file%" yn cael ei ddefnyddio eisoes gan is-gyfeiriadur arall.
+ServerNotAvailable=Nid yw'r gweinydd ar gael. Gwiriwch eich cysylltiad a cheisiwch eto yn ddiweddarach.
+Offline=Rydych all-lein. Cliciwch yr eicon wrth ymyl y gornel de gwaelod unrhyw ffenestr i fynd ar-lein.
+DiskFull=Does dim digon o le ar ddisg ar gael i gadw ffeil "%file%."
+NameTooLong=Mae'r enw ffeil neu is-gyfeiriadur yn rhy hir.
+AccessDenied=Does gennych ddim caniatâd i chi gyhoeddi i'r lleoliad hwn.
+UnknownPublishError=Digwyddodd gwall cyhoeddi anhysbys.
+PublishFailed=Methodd y cyhoeddi.
+PublishCompleted=Wedi cwblhau'r cyhoeddi.
+AllFilesPublished=Pob ffeil eu cyhoeddi
+# LOCALIZATION NOTE Don't translate %x% or %total%
+FailedFileMsg=Methodd %x% o %total% ffeil gael eu cyhoeddi.
+# End-Publishing error strings
+Prompt=Anogiad
+# LOCALIZATION NOTE (PromptFTPUsernamePassword): Don't translate %host% 
+PromptFTPUsernamePassword=Rhowch enw defnyddiwr a chyfrinair ar gyfer gweinydd FTP %host%
+RevertCaption=Dychwelyd i Cadwyd Diwethaf
+Revert=Dychwelyd
+SendPageReason=cyn anfon y dudalen
+Send=Anfon
+## LOCALIZATION NOTE (PublishProgressCaption, PublishToSite, AbandonChanges): Don't translate %title%
+PublishProgressCaption=Cyhoeddi: %title%
+PublishToSite=Cyhoeddi i Wefan: %title%
+AbandonChanges=Gadael newidiadau heb eu cadw i "%title%" ac ail-lwytho'r dudalen?
+DocumentTitle=Teitl y Dudalen
+NeedDocTitle=Rhoi teitl i'r dudalen gyfredol.
+DocTitleHelp=Mae hwn yn adnabod y dudalen yn nheitl y ffenestr a'r nodau tudalen.
+CancelPublishTitle=Diddymu'r cyhoeddi?
+## LOCALIZATION NOTE: "Continue" in this sentence must match the text for
+## the CancelPublishContinue key below
+CancelPublishMessage=Gall diddymu argraffu arwain at eich ffeil(iau)'n cael eu trosglwyddo'n wallus. Parhau neu Diddymu?
+CancelPublishContinue=Parhau
+MissingImageError=Rhoi neu ddewis ddelwedd gif, jpg, neu png.
+EmptyHREFError=Rhaid rhoi neu ddewis lleoliad i greu dolen newydd.
+LinkText=Cysylltu Testun
+LinkImage=Cysylltu Delwedd
+MixedSelection=[Dewis cymysg]
+Mixed=(cymysg)
+# LOCALIZATION NOTE (NotInstalled): %S is the name of the font
+NotInstalled=%S (heb ei osod)
+EnterLinkText=Rhoi testun i'w arddangos ar gyfer y ddolen:
+EnterLinkTextAccessKey=T
+EmptyLinkTextError=Rhowch ychydig o destun ar gyfer y ddolen.
+EditTextWarning=Bydd hwn yn cymryd lle'r cynnwys cyfredol.
+#LOCALIZATION NOTE (ValidateNumber):Don't translate: %n% %min% %max%
+ValidateRangeMsg=Mae'r rhif rydych wedi'i rhoi (%n%) tu allan i'r amrediad sy'n cael ei ganiatáu.
+ValidateNumberMsg=Rhowch rif rhwng %min% a %max%.
+MissingAnchorNameError=Rhowch enw i'r angor.
+#LOCALIZATION NOTE (DuplicateAnchorNameError): Don't translate %name%
+DuplicateAnchorNameError=Mae "%name%" yn bodoli eisoes ar y dudalen. Rhowch enw gwahanol.
+BulletStyle=Arddull Bwled
+SolidCircle=Cylch solet
+OpenCircle=Cylch agored
+SolidSquare=Sgwâr solet
+NumberStyle=Arddull Rhif
+Automatic=Awtomatig
+Style_1=1, 2, 3…
+Style_I=I, II, III…
+Style_i=i, ii, iii…
+Style_A=A, B, C…
+Style_a=a, b, c…
+Pixels=picseli
+Percent=y cant
+PercentOfCell=% o gell
+PercentOfWindow=% o ffenestr
+PercentOfTable=% o dabl
+#LOCALIZATION NOTE (untitledTitle): %S is the window #.  No plural handling needed.
+untitledTitle=dideitl-%S
+untitledDefaultFilename=dideitl
+ShowToolbar=Dangos Bar Offer
+HideToolbar=Cuddio'r Bar Offer
+ImapError=Methu llwytho'r ddelwedd\u0020
+ImapCheck=\nDewiswch leoliad (URL) newydd a cheisiwch eto.
+SaveToUseRelativeUrl=Dim ond ar dudalennau sydd wedi'u cadw mae modd defnyddio URL sy'n perthyn
+NoNamedAnchorsOrHeadings=(Nid oes angorau a enwyd na phenawdau ar y dudalen)
+TextColor=Lliw Testun
+HighlightColor=Lliw Amlygu
+PageColor=Lliw Cefndir Tudalen
+BlockColor=Rhwystro Cefndir Lliw
+TableColor=Lliw Cefndir Tabl
+CellColor=Lliw Cefndir Cell
+TableOrCellColor=Lliw Tabl neu Gell
+LinkColor=Lliw'r Testun Dolen
+ActiveLinkColor=Lliw Dolen Gweithredol
+VisitedLinkColor=Lliw Dolen Ymwelwyd
+NoColorError=Cliciwch ar liw neu roi llinyn lliw o HTML dilys
+Table=Tabl
+TableCell=Cell Tabl
+NestedTable=Tabl Nythwyd
+HLine=Llinell Llorweddol
+Link=Dolen
+Image=Delwedd
+ImageAndLink=Delwedd a Dolen
+NamedAnchor=Angor a Enwyd
+List=Rhestr
+ListItem=Rhestri'r eitem
+Form=Ffurflen
+InputTag=Maes Ffurflen
+InputImage=Delwedd Ffurflen
+TextArea=Ardal Testun
+Select=Rhestr Dewis
+Button=Botwm
+Label=Label
+FieldSet=Set Maes
+Tag=Tag
+MissingSiteNameError=Rhowch enw ar gyfer y wefan cyhoeddi.
+MissingPublishUrlError=Rhowch leoliad i gyhoeddi'r dudalen.
+MissingPublishFilename=Rhowch enw ffeil ar gyfer y dudalen gyfredol.
+#LOCALIZATION NOTE (DuplicateSiteNameError): Don't translate %name%
+DuplicateSiteNameError=Mae "%name%" yn bodoli eisoes. Rhowch enw safle gwahanol.
+AdvancedProperties=Priodweddau Uwch…
+AdvancedEditForCellMsg=Nid yw Golygu Uwch ar gael pan fydd celloedd niferus wedi'u dewis
+# LOCALIZATION NOTE (ObjectProperties):Don't translate "%obj%" it will be replaced with one of above object nouns
+ObjectProperties=Priodweddau %obj%…
+# LOCALIZATION NOTE This character must be in the above string and not confict with other accesskeys in Format menu
+ObjectPropertiesAccessKey=o
+# LOCALIZATION NOTE (JoinSelectedCells): This variable should contain the "tableJoinCells.accesskey" 
+# letter as defined in editorOverlay.dtd
+JoinSelectedCells=Uno'r Celloedd
+# LOCALIZATION NOTE (JoinCellToRight): This variable should contain the "tableJoinCells.accesskey" 
+# letter as defined in editorOverlay.dtd
+JoinCellToRight=Uno gyda'r Gell i'r Dde
+JoinCellAccesskey=j
+# LOCALIZATION NOTE (TableSelectKey): Ctrl key on a keyboard
+TableSelectKey=Ctrl+
+# LOCALIZATION NOTE (XulKeyMac): Command key on a Mac keyboard
+XulKeyMac=Cmd+
+# LOCALIZATION NOTE (Del): Del key on a keyboard
+Del=Del
+Delete=Dileu
+DeleteCells=Dileu Celloedd
+DeleteTableTitle=Dileu Rhesi neu Golofnau
+DeleteTableMsg=Bydd lleihau'r nifer o resi neu golofnau yn dileu celloedd tabl a'u cynnwys. Ydych chi wir eisiau gwneud hyn?
+Clear=Clirio
+#Mouse actions
+Click=Cliciwch
+Drag=Llusgo
+Unknown=Anhysbys
+#
+# LOCALIZATION NOTE "RemoveTextStylesAccesskey" is used for both
+#  menu items: "RemoveTextStyles" and "StopTextStyles"
+RemoveTextStylesAccesskey=x
+RemoveTextStyles=Tynnu Pob Arddull Testun
+StopTextStyles=Peidio Parhau gyda'r Arddulliau Testun
+#
+# LOCALIZATION NOTE "RemoveLinksAccesskey" is used for both
+#  menu items: "RemoveLinks" and "StopLinks"
+RemoveLinksAccesskey=n
+RemoveLinks=Tynnu Dolenni
+StopLinks=Peidio Parhau gyda'r Ddolen
+#
+NoFormAction=Awgrymir eich bod yn rhoi gweithred ar gyfer y ffurflen. Nid yw ffurflenni hunan gofnodi'n gweithio ar bob porwr am ei fod yn dechneg flaengar.
+NoAltText=Argymhellir eich bod yn darparu testun arall fydd yn ymddangos mewn porwyr testun yn unig, a fydd hefyd yn ymddangos mewn porwyr eraill pan fydd delwedd yn llwytho neu pan fo llwytho delwedd wedi'i analluogi.
+#
+Malformed=Nid oedd modd trosi'r ffynhonnell yn ôl i'r ddogfen am nad yw'n XHTML dilys.
+NoLinksToCheck=Does dim elfennau gyda chysylltiadau i'w gwirio
diff --git a/l10n-cy/editor/ui/chrome/composer/editorOverlay.dtd b/l10n-cy/editor/ui/chrome/composer/editorOverlay.dtd
new file mode 100644
index 0000000000..e3b9c49832
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editorOverlay.dtd
@@ -0,0 +1,371 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Attn: Localization - some of the menus in this dialog directly affect mail also. -->
+
+<!-- File menu items -->
+<!ENTITY saveCmd.key "S">
+
+<!-- Edit menu items -->
+<!ENTITY pasteNoFormatting.label "Gludo heb fformatio">
+<!ENTITY pasteNoFormatting.accesskey "G">
+<!ENTITY pasteNoFormatting.key "V">
+<!ENTITY pasteAs.label "Gludo Fel">
+<!ENTITY pasteAs.accesskey "G">
+<!ENTITY pasteAsQuotationCmd.label "Gludo fel Dyfyniad">
+<!ENTITY pasteAsQuotationCmd.accesskey "D">
+<!ENTITY pasteAsQuotationCmd.key "o">
+<!ENTITY findBarCmd.label "Canfod…">
+<!ENTITY findReplaceCmd.label "Canfod a Newid…">
+<!ENTITY enableInlineSpellChecker.label "Gwirio Sillafu Wrth Deipio">
+<!ENTITY enableInlineSpellChecker.accesskey "S">
+<!ENTITY checkSpellingCmd2.label "Gwirio Sillafu…">
+<!ENTITY checkSpellingCmd2.accesskey "G">
+<!ENTITY checkSpellingCmd2.key "p">
+
+<!-- Insert menu items -->
+<!ENTITY insertMenu.label "Mewnosod">
+<!ENTITY insertMenu.accesskey "M">
+<!ENTITY insertLinkCmd2.label "Dolen…">
+<!ENTITY insertLinkCmd2.accesskey "D">
+<!ENTITY insertLinkCmd2.key "K">
+<!ENTITY insertAnchorCmd.label "Angor a Enwyd…">
+<!ENTITY insertAnchorCmd.accesskey "A">
+<!ENTITY insertImageCmd.label "Delwedd…">
+<!ENTITY insertImageCmd.accesskey "D">
+<!ENTITY insertHLineCmd.label "Llinell Llorweddol">
+<!ENTITY insertHLineCmd.accesskey "l">
+<!ENTITY insertTableCmd.label "Tabl…">
+<!ENTITY insertTableCmd.accesskey "T">
+<!ENTITY insertHTMLCmd.label "HTML…">
+<!ENTITY insertHTMLCmd.accesskey "H">
+<!ENTITY insertMathCmd.label "Mathemateg…">
+<!ENTITY insertMathCmd.accesskey "M">
+<!ENTITY insertCharsCmd.label "Nodau a Symbolau…">
+<!ENTITY insertCharsCmd.accesskey "N">
+<!ENTITY insertBreakAllCmd.label "Toriad Islaw Delwedd(au)">
+<!ENTITY insertBreakAllCmd.accesskey "I">
+
+<!-- Used just in context popup. -->
+<!ENTITY createLinkCmd.label "Creu Dolen…">
+<!ENTITY createLinkCmd.accesskey "D">
+<!ENTITY editLinkCmd.label "Golygu'r ddolen o fewn Cyfansoddwr Newydd">
+<!ENTITY editLinkCmd.accesskey "G">
+
+<!-- Font Face SubMenu -->
+<!ENTITY FontFaceSelect.title "Ffont">
+<!ENTITY FontFaceSelect.tooltip "Dewiswch ffont">
+<!ENTITY fontfaceMenu.label "Ffont">
+<!ENTITY fontfaceMenu.accesskey "F">
+<!ENTITY fontVarWidth.label "Lled Newidiol">
+<!ENTITY fontVarWidth.accesskey "N">
+<!ENTITY fontFixedWidth.label "Lled Osodedig">
+<!ENTITY fontFixedWidth.accesskey "O">
+<!ENTITY fontFixedWidth.key "T">
+<!ENTITY fontHelvetica.label "Helvetica, Arial">
+<!ENTITY fontHelvetica.accesskey "l">
+<!ENTITY fontTimes.label "Times">
+<!ENTITY fontTimes.accesskey "T">
+<!ENTITY fontCourier.label "Courier">
+<!ENTITY fontCourier.accesskey "C">
+
+<!-- Font Size SubMenu -->
+<!ENTITY FontSizeSelect.title "Maint Ffont">
+<!ENTITY FontSizeSelect.tooltip "Dewiswch faint y ffont">
+<!ENTITY decreaseFontSize.label "Llai">
+<!ENTITY decreaseFontSize.accesskey "L">
+<!ENTITY decrementFontSize.key "&lt;">
+<!ENTITY decrementFontSize.key2 ","> <!-- < is above this key on many keyboards -->
+<!ENTITY increaseFontSize.label "Mwy">
+<!ENTITY increaseFontSize.accesskey "M">
+<!ENTITY incrementFontSize.key "&gt;">
+<!ENTITY incrementFontSize.key2 "."> <!-- > is above this key on many keyboards -->
+
+<!ENTITY fontSizeMenu.label "Maint">
+<!ENTITY fontSizeMenu.accesskey "M">
+<!ENTITY size-tinyCmd.label "Bach Iawn">
+<!ENTITY size-tinyCmd.accesskey "I">
+<!ENTITY size-smallCmd.label "Bach">
+<!ENTITY size-smallCmd.accesskey "B">
+<!ENTITY size-mediumCmd.label "Canolig">
+<!ENTITY size-mediumCmd.accesskey "C">
+<!ENTITY size-largeCmd.label "Mawr">
+<!ENTITY size-largeCmd.accesskey "M">
+<!ENTITY size-extraLargeCmd.label "Mawr Iawn">
+<!ENTITY size-extraLargeCmd.accesskey "w">
+<!ENTITY size-hugeCmd.label "Anferth">
+<!ENTITY size-hugeCmd.accesskey "A">
+
+<!-- Font Style SubMenu -->
+<!ENTITY fontStyleMenu.label "Arddull Testun">
+<!ENTITY fontStyleMenu.accesskey "A">
+<!ENTITY styleBoldCmd.label "Trwm">
+<!ENTITY styleBoldCmd.accesskey "T">
+<!ENTITY styleBoldCmd.key "B">
+<!ENTITY styleItalicCmd.label "Italig">
+<!ENTITY styleItalicCmd.accesskey "I">
+<!ENTITY styleItalicCmd.key "I">
+<!ENTITY styleUnderlineCmd.label "Tanlinellu">
+<!ENTITY styleUnderlineCmd.accesskey "a">
+<!ENTITY styleUnderlineCmd.key "U">
+<!ENTITY styleStrikeThruCmd.label "Taro drwodd">
+<!ENTITY styleStrikeThruCmd.accesskey "o">
+<!ENTITY styleSuperscriptCmd.label "Uwchysgrif">
+<!ENTITY styleSuperscriptCmd.accesskey "U">
+<!ENTITY styleSubscriptCmd.label "Isysgrif">
+<!ENTITY styleSubscriptCmd.accesskey "I">
+<!ENTITY styleNonbreakingCmd.label "Ddim yn torri">
+<!ENTITY styleNonbreakingCmd.accesskey "D">
+<!ENTITY styleEm.label "Pwyslais">
+<!ENTITY styleEm.accesskey "P">
+<!ENTITY styleStrong.label "Pwyslais Cryfach">
+<!ENTITY styleStrong.accesskey "C">
+<!ENTITY styleCite.label "Dyfyniad">
+<!ENTITY styleCite.accesskey "D">
+<!ENTITY styleAbbr.label "Byrfodd">
+<!ENTITY styleAbbr.accesskey "B">
+<!ENTITY styleAcronym.label "Acronym">
+<!ENTITY styleAcronym.accesskey "A">
+<!ENTITY styleCode.label "Cod">
+<!ENTITY styleCode.accesskey "o">
+<!ENTITY styleSamp.label "Sampl Allbwn">
+<!ENTITY styleSamp.accesskey "S">
+<!ENTITY styleVar.label "Newidiol">
+<!ENTITY styleVar.accesskey "N">
+
+<!ENTITY formatFontColor.label "Lliw'r Testun…">
+<!ENTITY formatFontColor.accesskey "L">
+<!ENTITY tableOrCellColor.label "Lliw Cefndir y Tabl neu'r Gell…">
+<!ENTITY tableOrCellColor.accesskey "C">
+
+<!ENTITY formatRemoveStyles.key "Y">
+<!ENTITY formatRemoveLinks.key "K">
+<!ENTITY formatRemoveNamedAnchors.label "Tynnu Angorau Enwyd">
+<!ENTITY formatRemoveNamedAnchors.accesskey "T">
+<!ENTITY formatRemoveNamedAnchors2.key "R">
+
+<!ENTITY paragraphMenu.label "Paragraff">
+<!ENTITY paragraphMenu.accesskey "P">
+<!ENTITY paragraphParagraphCmd.label "Paragraff">
+<!ENTITY paragraphParagraphCmd.accesskey "P">
+<!ENTITY heading1Cmd.label "Pennyn 1">
+<!ENTITY heading1Cmd.accesskey "1">
+<!ENTITY heading2Cmd.label "Pennyn 2">
+<!ENTITY heading2Cmd.accesskey "2">
+<!ENTITY heading3Cmd.label "Pennyn 3">
+<!ENTITY heading3Cmd.accesskey "3">
+<!ENTITY heading4Cmd.label "Pennyn 4">
+<!ENTITY heading4Cmd.accesskey "4">
+<!ENTITY heading5Cmd.label "Pennyn 5">
+<!ENTITY heading5Cmd.accesskey "5">
+<!ENTITY heading6Cmd.label "Pennyn 6">
+<!ENTITY heading6Cmd.accesskey "6">
+<!ENTITY paragraphAddressCmd.label "Cyfeiriad">
+<!ENTITY paragraphAddressCmd.accesskey "C">
+<!ENTITY paragraphPreformatCmd.label "Rhagfformatio">
+<!ENTITY paragraphPreformatCmd.accesskey "R">
+
+<!-- List menu items -->
+<!ENTITY formatlistMenu.label "Rhestr">
+<!ENTITY formatlistMenu.accesskey "R">
+<!ENTITY noneCmd.label "Dim">
+<!ENTITY noneCmd.accesskey "D">
+<!ENTITY listBulletCmd.label "Bwledwyd">
+<!ENTITY listBulletCmd.accesskey "B">
+<!ENTITY listNumberedCmd.label "Rhifwyd">
+<!ENTITY listNumberedCmd.accesskey "R">
+<!ENTITY listTermCmd.label "Term">
+<!ENTITY listTermCmd.accesskey "T">
+<!ENTITY listDefinitionCmd.label "Diffiniad">
+<!ENTITY listDefinitionCmd.accesskey "D">
+<!ENTITY listPropsCmd.label "Priodweddau'r Rhestr…">
+<!ENTITY listPropsCmd.accesskey "R">
+
+<!ENTITY ParagraphSelect.title "Paragraff">
+<!ENTITY ParagraphSelect.tooltip "Dewiswch fformat paragraff">
+<!-- Shared in Paragraph, and Toolbar menulist -->
+<!ENTITY bodyTextCmd.label "Corff y Testun">
+<!ENTITY bodyTextCmd.accesskey "C">
+<!-- isn't used in menu now, but may be added in future -->
+<!ENTITY advancedPropertiesCmd.label "Priodweddau Uwch">
+<!ENTITY advancedPropertiesCmd.accesskey "U">
+
+<!-- Align menu items -->
+<!ENTITY alignMenu.label "Alinio">
+<!ENTITY alignMenu.accesskey "A">
+<!ENTITY alignLeft.label "Chwith">
+<!ENTITY alignLeft.accesskey "C">
+<!ENTITY alignLeft.tooltip "Alinio i'r Chwith">
+<!ENTITY alignCenter.label "Canol">
+<!ENTITY alignCenter.accesskey "a">
+<!ENTITY alignCenter.tooltip "Alinio i'r Canol">
+<!ENTITY alignRight.label "De">
+<!ENTITY alignRight.accesskey "D">
+<!ENTITY alignRight.tooltip "Alinio i'r Dde">
+<!ENTITY alignJustify.label "Unioni">
+<!ENTITY alignJustify.accesskey "U">
+<!ENTITY alignJustify.tooltip "Alinio Unioni">
+
+<!-- Layer toolbar items -->
+<!ENTITY absolutePosition.label "Lleoli">
+<!ENTITY layer.tooltip "Haen">
+<!ENTITY decreaseZIndex.label "Anfon i'r Cefn">
+<!ENTITY layerSendToBack.tooltip "Anfon i'r Cefn">
+<!ENTITY increaseZIndex.label "Dwyn i'r Blaen">
+<!ENTITY layerBringToFront.tooltip "Dwyn i'r Blaen">
+
+<!ENTITY increaseIndent.label "Cynyddu'r Mewnoliad">
+<!ENTITY increaseIndent.accesskey "y">
+<!ENTITY increaseIndent.key "]">
+<!ENTITY decreaseIndent.label "Lleihau Mewnoliad">
+<!ENTITY decreaseIndent.accesskey "L">
+<!ENTITY decreaseIndent.key "[">
+
+<!ENTITY colorsAndBackground.label "Lliwiau Tudalen a Chefndir…">
+<!ENTITY colorsAndBackground.accesskey "L">
+
+<!-- Table Menu -->
+<!ENTITY tableMenu.label "Tabl">
+<!ENTITY tableMenu.accesskey "b">
+
+<!-- Select Submenu -->
+<!ENTITY tableSelectMenu.label "Dewis">
+<!ENTITY tableSelectMenu.accesskey "D">
+
+<!ENTITY tableSelectMenu2.label "Dewis Tabl">
+<!ENTITY tableSelectMenu2.accesskey "T">
+<!ENTITY tableInsertMenu2.label "Mewnosod Tabl">
+<!ENTITY tableInsertMenu2.accesskey "M">
+<!ENTITY tableDeleteMenu2.label "Dileu Tabl">
+<!ENTITY tableDeleteMenu2.accesskey "D">
+
+<!-- Insert SubMenu -->
+<!ENTITY tableInsertMenu.label "Mewnosod">
+<!ENTITY tableInsertMenu.accesskey "M">
+<!ENTITY tableTable.label "Tabl">
+<!ENTITY tableTable.accesskey "T">
+<!ENTITY tableRow.label "Rhes">
+<!ENTITY tableRows.label "Rhes(i)">
+<!ENTITY tableRow.accesskey "R">
+<!ENTITY tableRowAbove.label "Rhes Uwchben">
+<!ENTITY tableRowAbove.accesskey "U">
+<!ENTITY tableRowBelow.label "Rhes Islaw">
+<!ENTITY tableRowBelow.accesskey "I">
+<!ENTITY tableColumn.label "Colofn">
+<!ENTITY tableColumns.label "Colofn(au)">
+<!ENTITY tableColumn.accesskey "o">
+<!ENTITY tableColumnBefore.label "Colofn Cynt">
+<!ENTITY tableColumnBefore.accesskey "y">
+<!ENTITY tableColumnAfter.label "Colofn yn Dilyn">
+<!ENTITY tableColumnAfter.accesskey "D">
+<!ENTITY tableCell.label "Cell">
+<!ENTITY tableCells.label "Cell(oedd)">
+<!ENTITY tableCell.accesskey "C">
+<!ENTITY tableCellContents.label "Cynnwys Cell">
+<!ENTITY tableCellContents.accesskey "y">
+<!ENTITY tableAllCells.label "Pob Cell">
+<!ENTITY tableAllCells.accesskey "P">
+<!ENTITY tableCellBefore.label "Cell Cynt">
+<!ENTITY tableCellBefore.accesskey "e">
+<!ENTITY tableCellAfter.label "Cell yn Dilyn">
+<!ENTITY tableCellAfter.accesskey "i">
+<!-- Delete SubMenu -->
+<!ENTITY tableDeleteMenu.label "Dileu">
+<!ENTITY tableDeleteMenu.accesskey "D">
+
+<!-- text for "Join Cells" is in editor.properties
+     ("JoinSelectedCells" and "JoinCellToRight")
+     the access key must exist in both of those strings
+     But value must be set here for accesskey to draw properly
+-->
+<!ENTITY tableJoinCells.label "j">
+<!ENTITY tableJoinCells.accesskey "j">
+<!ENTITY tableSplitCell.label "Rhannu Cell">
+<!ENTITY tableSplitCell.accesskey "R">
+<!ENTITY convertToTable.label "Creu Tabl o'r Dewis">
+<!ENTITY convertToTable.accesskey "D">
+<!ENTITY tableProperties.label "Priodweddau Tabl…">
+<!ENTITY tableProperties.accesskey "P">
+
+<!-- Toolbar-only items -->
+<!ENTITY menuBar.tooltip "Bar Dewislen">
+<!ENTITY formatToolbar.tooltip "Bar Offer Fformatio">
+<!ENTITY cutToolbarCmd.tooltip "Torri">
+<!ENTITY copyToolbarCmd.tooltip "Copïo">
+<!ENTITY pasteToolbarCmd.tooltip "Gludo">
+<!ENTITY printToolbarCmd.label "Argraffu">
+<!ENTITY printToolbarCmd.tooltip "Argraffu'r dudalen">
+<!ENTITY findToolbarCmd.label "Canfod">
+<!ENTITY findToolbarCmd.tooltip "Canfod y testun ar y dudalen">
+<!ENTITY spellToolbarCmd.label "Sillafu">
+<!ENTITY spellToolbarCmd.tooltip "Gwirio sillafu o adran neu o'r dudalen gyfan">
+<!ENTITY imageToolbarCmd.label "Delwedd">
+<!ENTITY imageToolbarCmd.tooltip "Mewnosod delwedd newydd neu olygu priodweddau'r ddelwedd">
+<!ENTITY hruleToolbarCmd.label "H.Line">
+<!ENTITY hruleToolbarCmd.tooltip "Mewnosod llinell lorweddol neu olygu priodweddau'r ddelwedd">
+<!ENTITY tableToolbarCmd.label "Tabl">
+<!ENTITY tableToolbarCmd.tooltip "Mewnosod tabl newydd neu olygu priodweddau'r tabl">
+<!ENTITY linkToolbarCmd.label "Dolen">
+<!ENTITY linkToolbarCmd.tooltip "Mewnosod dolen newydd neu olygu priodweddau'r ddolen">
+<!ENTITY anchorToolbarCmd.label "Angor">
+<!ENTITY anchorToolbarCmd.tooltip "Mewnosod angor a enwyd neu olygu priodweddau'r angor">
+<!ENTITY colorButtons.title "Lliwiau">
+<!ENTITY TextColorButton.tooltip "Dewiswch liw i'r testun">
+<!ENTITY BackgroundColorButton.tooltip "Dewiswch liw i'r cefndir">
+<!ENTITY throbber.tooltip "Mynd i dudalen gartref &vendorShortName;">
+<!ENTITY throbber.tooltip2 "Ewch i dudalen cartref &brandShortName;">
+<!ENTITY HighlightColorButton.label "Amlygwr">
+<!ENTITY HighlightColorButton.tooltip "Dewis lliw amlygu ar gyfer y testun">
+
+<!-- Editor toolbar -->
+<!ENTITY absoluteFontSize.label "Maint Ffont">
+<!ENTITY absoluteFontSizeToolbarCmd.tooltip "Gosod maint ffont">
+<!ENTITY smaller.label "Llai">
+<!ENTITY decreaseFontSizeToolbarCmd.tooltip "Maint ffont lai">
+<!ENTITY larger.label "Mwy">
+<!ENTITY increaseFontSizeToolbarCmd.tooltip "Maint ffont mwy">
+<!ENTITY bold.label "Trwm">
+<!ENTITY boldToolbarCmd.tooltip "Trwm">
+<!ENTITY italic.label "Italig">
+<!ENTITY italicToolbarCmd.tooltip "Italig">
+<!ENTITY underline.label "Tanlinellu">
+<!ENTITY underlineToolbarCmd.tooltip "Tanlinellu">
+<!ENTITY bullets.label "Bwledi">
+<!ENTITY bulletListToolbarCmd.tooltip "Gosod neu ddiddymu rhestr bwledi">
+<!ENTITY numbers.label "Rhifau">
+<!ENTITY numberListToolbarCmd.tooltip "Gosod neu ddiddymu rhestr rhifedig">
+<!ENTITY outdent.label "Alloliad">
+<!ENTITY outdentToolbarCmd.tooltip "Alloliad testun (symud i'r chwith)">
+<!ENTITY indent.label "Mewnoliad">
+<!ENTITY indentToolbarCmd.tooltip "Mewnoliad testun (symud i'r dde)">
+<!ENTITY AlignPopupButton.label "Aliniad">
+<!ENTITY AlignPopupButton.tooltip "Dewis aliniad testun">
+<!ENTITY InsertPopupButton.label "Mewnosod">
+<!ENTITY InsertPopupButton.tooltip "Mewnosod Dolen, Angor, Delwedd, Llinell Lorweddol neu Dabl">
+<!ENTITY alignLeftButton.label "Alinio i'r Chwith">
+<!ENTITY alignLeftButton.tooltip "Alinio testun ar hyd yr ymyl chwith">
+<!ENTITY alignCenterButton.label "Alinio i'r Canol">
+<!ENTITY alignCenterButton.tooltip "Alinio testun wedi'i ganoli">
+<!ENTITY alignRightButton.label "Alinio i'r Dde">
+<!ENTITY alignRightButton.tooltip "Alinio testun ar hyd yr ymyl dde">
+<!ENTITY alignJustifyButton.label "Alinio Unioni">
+<!ENTITY alignJustifyButton.tooltip "Alinio testun ar hyd ymylon de a chwith">
+
+<!-- Structure Toolbar Context Menu items -->
+<!ENTITY structSelect.label         "Dewis">
+<!ENTITY structSelect.accesskey     "D">
+<!ENTITY structRemoveTag.label      "Tynnu tag">
+<!ENTITY structRemoveTag.accesskey  "T">
+<!ENTITY structChangeTag.label      "Newid tag">
+<!ENTITY structChangeTag.accesskey  "N">
+
+<!-- TOC manipulation -->
+<!ENTITY insertTOC.label          "Mewnosod">
+<!ENTITY insertTOC.accesskey      "M">
+<!ENTITY updateTOC.label          "Diweddaru">
+<!ENTITY updateTOC.accesskey      "u">
+<!ENTITY removeTOC.label          "Tynnu">
+<!ENTITY removeTOC.accesskey      "T">
+<!ENTITY tocMenu.label            "Tabl Cynnwys…">
+<!ENTITY tocMenu.accesskey        "C">
diff --git a/l10n-cy/editor/ui/chrome/composer/editorPrefsOverlay.dtd b/l10n-cy/editor/ui/chrome/composer/editorPrefsOverlay.dtd
new file mode 100644
index 0000000000..5c2bbd27c4
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editorPrefsOverlay.dtd
@@ -0,0 +1,13 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!--LOCALIZATION NOTE (editorCheck.label): DONT_TRANSLATE -->
+
+
+<!ENTITY editorCheck.label "Composer">
+<!ENTITY editorCheck.accesskey "c">
+
+<!ENTITY compose.label "Cyfansoddwr">
+<!ENTITY editing.label "Gosodiadau Tudalen Newydd">
+<!ENTITY toolbars.label "Barrau Offer">
+<!ENTITY publish.label "Cyhoeddi">
diff --git a/l10n-cy/editor/ui/chrome/composer/editorSmileyOverlay.dtd b/l10n-cy/editor/ui/chrome/composer/editorSmileyOverlay.dtd
new file mode 100644
index 0000000000..4a37f2be0d
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/editorSmileyOverlay.dtd
@@ -0,0 +1,58 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Smiley Menu items -->
+<!ENTITY insertSmiley.label "Gwenog">
+<!ENTITY insertSmiley.accesskey "G">
+
+<!ENTITY smiley1Cmd.label "Gwên">
+<!ENTITY smiley1Cmd.accesskey "w">
+<!ENTITY smiley1Cmd.tooltip "Mewnosod wyneb gwenog">
+<!ENTITY smiley2Cmd.label "Gwg">
+<!ENTITY smiley2Cmd.accesskey "G">
+<!ENTITY smiley2Cmd.tooltip "Mewnosod wyneb gwg">
+<!ENTITY smiley3Cmd.label "Chwinc">
+<!ENTITY smiley3Cmd.accesskey "C">
+<!ENTITY smiley3Cmd.tooltip "Mewnosod wyneb chwinciog">
+<!ENTITY smiley4Cmd.label "Tafod allan">
+<!ENTITY smiley4Cmd.accesskey "T">
+<!ENTITY smiley4Cmd.tooltip "Mewnosod wyneb tafod hir">
+<!ENTITY smiley5Cmd.label "Chwerthin">
+<!ENTITY smiley5Cmd.accesskey "C">
+<!ENTITY smiley5Cmd.tooltip "Mewnosod wyneb chwerthin">
+<!ENTITY smiley6Cmd.label "Embaras">
+<!ENTITY smiley6Cmd.accesskey "E">
+<!ENTITY smiley6Cmd.tooltip "Mewnosod wyneb embaras">
+<!ENTITY smiley7Cmd.label "Heb benderfynu">
+<!ENTITY smiley7Cmd.accesskey "H">
+<!ENTITY smiley7Cmd.tooltip "Mewnosod wyneb heb benderfynu">
+<!ENTITY smiley8Cmd.label "Syndod">
+<!ENTITY smiley8Cmd.accesskey "S">
+<!ENTITY smiley8Cmd.tooltip "Mewnosod wyneb syn">
+<!ENTITY smiley9Cmd.label "Cusan">
+<!ENTITY smiley9Cmd.accesskey "u">
+<!ENTITY smiley9Cmd.tooltip "Mewnosod wyneb cusan">
+<!ENTITY smiley10Cmd.label "Gwaedd">
+<!ENTITY smiley10Cmd.accesskey "e">
+<!ENTITY smiley10Cmd.tooltip "Mewnosod wyneb gweiddi">
+<!ENTITY smiley11Cmd.label "Cwl">
+<!ENTITY smiley11Cmd.accesskey "l">
+<!ENTITY smiley11Cmd.tooltip "Mewnosod wyneb cwl">
+<!ENTITY smiley12Cmd.label "Ceg Aur">
+<!ENTITY smiley12Cmd.accesskey "A">
+<!ENTITY smiley12Cmd.tooltip "Mewnosod wyneb ceg arian">
+<!ENTITY smiley13Cmd.label "Ceg Fawr">
+<!ENTITY smiley13Cmd.accesskey "F">
+<!ENTITY smiley13Cmd.tooltip "Mewnosod wyneb ceg fawr">
+<!ENTITY smiley14Cmd.label "Diniwed">
+<!ENTITY smiley14Cmd.accesskey "D">
+<!ENTITY smiley14Cmd.tooltip "Mewnosod wyneb diniwed">
+<!ENTITY smiley15Cmd.label "Crio">
+<!ENTITY smiley15Cmd.accesskey "r">
+<!ENTITY smiley15Cmd.tooltip "Mewnosod wyneb crio">
+<!ENTITY smiley16Cmd.label "Dim Gair!">
+<!ENTITY smiley16Cmd.accesskey "D">
+<!ENTITY smiley16Cmd.tooltip "Mewnosod wyneb dim gair">
+<!ENTITY SmileButton.label "Mewnosod Gwenoglun">
+<!ENTITY SmileButton.tooltip "Mewnosod wyneb gwenog">
diff --git a/l10n-cy/editor/ui/chrome/composer/pref-composer.dtd b/l10n-cy/editor/ui/chrome/composer/pref-composer.dtd
new file mode 100644
index 0000000000..9d0ded2f07
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/pref-composer.dtd
@@ -0,0 +1,29 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- extracted from content/pref-composer.xul -->
+<!--LOCALIZATION NOTE : FILE 'Composer' prefs dialog. Similar to Communcator 4.x Document Properties/Colors and Background -->
+<!--LOCALIZATION NOTE (pref.composer.title): DONT_TRANSLATE -->
+
+
+
+<!ENTITY  pref.composer.title           "Composer">
+<!ENTITY  recentFiles.title             "Dewislen Tudalen Diweddar">
+<!ENTITY  documentsInMenu.label         "Nifer fwyaf o dudalennau wedi'u rhestru:">
+<!ENTITY  documentsInMenu.accesskey     "N">
+<!ENTITY  savingFiles.title             "Wrth Gadw neu Gyhoeddi Tudalennau">
+<!ENTITY  preserveExisting.label        "Cadw fformatio gwreiddiol y ffynhonnell">
+<!ENTITY  preserveExisting.accesskey    "f">
+<!ENTITY  preserveExisting.tooltip      "Cadw toriad llinell a fformatio gwreiddiol y dudalen">
+<!ENTITY  saveAssociatedFiles.label     "Cadw delweddau a ffeiliau cysylltiedig eraill wrth gadw tudalennau">
+<!ENTITY  saveAssociatedFiles.accesskey "d">
+<!ENTITY  showPublishDialog.label       "Dangos deialog Cyhoeddi wrth gyhoeddi tudalennau">
+<!ENTITY  showPublishDialog.accesskey   "D">
+<!ENTITY  composerEditing.label         "Golygu">
+<!ENTITY  maintainStructure.label       "Cadw cynllun tabl wrth fewnosod neu ddileu celloedd">
+<!ENTITY  maintainStructure.tooltip     "Cadw siâp petryal y tabl drwy ychwanegu celloedd yn awtomatig ar ôl mewnosod neu ddileu celloedd">
+<!ENTITY  maintainStructure.accesskey   "t">
+<!ENTITY  useCSS.label                  "Defnyddio arddulliau CSS yn lle elfennau a phriodweddau HTML">
+<!ENTITY  useCSS.accesskey              "a">
+<!ENTITY  crInPCreatesNewP.label        "Mae dychwelyd at baragraff yn creu paragraff newydd bob tro">
+<!ENTITY  crInPCreatesNewP.accesskey    "d">
diff --git a/l10n-cy/editor/ui/chrome/composer/pref-editing.dtd b/l10n-cy/editor/ui/chrome/composer/pref-editing.dtd
new file mode 100644
index 0000000000..9aed120104
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/composer/pref-editing.dtd
@@ -0,0 +1,32 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  pref.editing.title        "Gosodiadau Tudalen Newydd">
+
+<!ENTITY  authorName.label          "Awdur:">
+<!ENTITY  authorName.accesskey      "A">
+<!ENTITY  pageColorHeader           "Gwedd Tudalen Rhagosodedig">
+
+<!ENTITY defaultColors.label        "Lliwiau Rhagosodedig y Darllenydd (Peidio gosod lliwiau ar y dudalen)">
+<!ENTITY defaultColors.accesskey    "D">
+<!ENTITY customColors.label         "Defnyddio lliwiau cyfaddasu:">
+<!ENTITY customColors.accesskey     "c">
+
+<!ENTITY normalText.label           "Testun arferol">
+<!ENTITY normalText.accesskey       "a">
+<!ENTITY linkText.label             "Testun dolen">
+<!ENTITY linkText.accesskey         "d">
+<!ENTITY activeLinkText.label       "Cyswllt testun gweithredol">
+<!ENTITY activeLinkText.accesskey   "g">
+<!ENTITY visitedLinkText.label      "Testun dolen wedi ymweld">
+<!ENTITY visitedLinkText.accesskey  "y">
+<!ENTITY background.label           "Cefndir:">
+<!ENTITY background.accesskey       "C">
+<!ENTITY colon.character            ":">
+
+<!ENTITY backgroundImage.label      "Delwedd cefndir:">
+<!ENTITY backgroundImage.accesskey  "D">
+<!ENTITY chooseFile.label           "Dewis Ffeil…">
+<!ENTITY chooseFile.accesskey       "F">
+
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EdAdvancedEdit.dtd b/l10n-cy/editor/ui/chrome/dialogs/EdAdvancedEdit.dtd
new file mode 100644
index 0000000000..3521a919ef
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EdAdvancedEdit.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY WindowTitle.label              "Golygydd Priodwedd Uwch">
+<!ENTITY AttName.label                  "Priodoledd: ">
+<!ENTITY AttValue.label                 "Gwerth: ">
+<!ENTITY PropertyName.label             "Priodwedd: ">
+<!ENTITY currentattributesfor.label     "Priodweddau cyfredol: ">
+<!ENTITY tree.attributeHeader.label     "Priodoledd">
+<!ENTITY tree.propertyHeader.label      "Priodwedd">
+<!ENTITY tree.valueHeader.label         "Gwerth">
+<!ENTITY tabHTML.label                  "Priodweddau HTML">
+<!ENTITY tabCSS.label                   "Arddull Mewn-lein">
+<!ENTITY tabJSE.label                   "Digwyddiadau JavaScript">
+
+<!ENTITY editAttribute.label    "Cliciwch ar eitem i olygu ei gwerth">
+<!ENTITY removeAttribute.label  "Tynnu">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EdColorPicker.dtd b/l10n-cy/editor/ui/chrome/dialogs/EdColorPicker.dtd
new file mode 100644
index 0000000000..c3ded113f0
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EdColorPicker.dtd
@@ -0,0 +1,25 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Lliw">
+<!ENTITY lastPickedColor.label "Lliw dewiswyd diwethaf">
+<!ENTITY lastPickedColor.accessKey "L">
+<!ENTITY setColor1.label "Cliciwch ar liw neu">
+<!ENTITY setColor2.label "rhoi llinell HTML lliw">
+<!ENTITY setColor2.accessKey "H">
+<!ENTITY chooseColor1.label "Dewis lliw:">
+<!ENTITY chooseColor2.label "Rhoi llinyn liw HTML">
+<!ENTITY chooseColor2.accessKey "H">
+<!ENTITY setColorExample.label "(e.e.: &quot;#0000ff&quot; neu &quot;blue&quot;):">
+<!ENTITY default.label "Rhagosodiad">
+<!ENTITY default.accessKey "R">
+<!ENTITY palette.label "Palet:">
+<!ENTITY standardPalette.label "Safonol">
+<!ENTITY webPalette.label "Pob lliw gwe">
+<!ENTITY background.label "Cefndir i:">
+<!ENTITY background.accessKey "e">
+<!ENTITY table.label "Tabl">
+<!ENTITY table.accessKey "T">
+<!ENTITY cell.label "Cell(oedd)">
+<!ENTITY cell.accessKey "C">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EdConvertToTable.dtd b/l10n-cy/editor/ui/chrome/dialogs/EdConvertToTable.dtd
new file mode 100644
index 0000000000..d818f65eba
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EdConvertToTable.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Trosi i Dabl">
+<!ENTITY instructions1.label   "Mae Cyfansoddwr yn creu rhes tabl newydd am bob paragraff yn y dewis.">
+<!ENTITY instructions2.label   "Dewiswch y nod fydd yn cael ei ddefnyddio i wahanu'r dewis yn golofnau:">
+<!ENTITY commaRadio.label      "Collnod">
+<!ENTITY spaceRadio.label      "Lle">
+<!ENTITY otherRadio.label      "Nod Arall:">
+<!ENTITY deleteCharCheck.label "Dileu nod gwahanu">
+<!ENTITY collapseSpaces.label  "Anwybyddu'r bylchau ychwanegol">
+<!ENTITY collapseSpaces.tooltip "Trosi'r bylchau cyfagos i un gwahanydd">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EdDialogOverlay.dtd b/l10n-cy/editor/ui/chrome/dialogs/EdDialogOverlay.dtd
new file mode 100644
index 0000000000..121062d4b7
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EdDialogOverlay.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY AdvancedEditButton.label "Golygu Uwch…">
+<!ENTITY AdvancedEditButton.accessKey "G">
+<!ENTITY AdvancedEditButton.tooltip "Ychwanegu neu newid Priodweddau HTML, priodweddau arddulliau a JavaScript">
+<!ENTITY chooseFileButton.label "Dewis Ffeil...">
+<!ENTITY chooseFileButton.accessKey "D">
+<!ENTITY chooseFileLinkButton.label "Dewis Ffeil...">
+<!ENTITY chooseFileLinkButton.accessKey "D">
+<!ENTITY makeUrlRelative.label "Mae'r URL yn berthynol i'r lleoliad tudalen">
+<!ENTITY makeUrlRelative.accessKey "U">
+<!ENTITY makeUrlRelative.tooltip "Newid rhwng URL absoliwt a pherthynol. Rhaid cadw'r dudalen yn gyntaf cyn gwneud hyn.">
+
+<!-- Shared by Link and Image dialogs -->
+<!ENTITY LinkURLEditField.label "Rhowch leoliad tudalen gwe, ffeil leol neu ddewiswch Angor a Enwyd neu Bennyn o'r llamlen:">
+<!ENTITY LinkURLEditField.accessKey "R">
+<!ENTITY LinkURLEditField2.label "Rhowch leoliad tudalen gwe, ffeil leol neu ddewis Angor a Enwyd neu Bennawd o feysydd y ddewislen cyd-destun:">
+<!ENTITY LinkURLEditField2.accessKey "w">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EdNamedAnchorProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EdNamedAnchorProperties.dtd
new file mode 100644
index 0000000000..510508d130
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EdNamedAnchorProperties.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodoleddau'r Angor a Enwyd">
+<!ENTITY anchorNameEditField.label "Enw'r Angor:">
+<!ENTITY anchorNameEditField.accessKey "E">
+<!ENTITY nameInput.tooltip "Rhowch enw unigryw ar gyfer yr angor (targed)">
+
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditConflict.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditConflict.dtd
new file mode 100644
index 0000000000..2fc778d57e
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditConflict.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Dewis Newidiadau Golygu">
+<!ENTITY conflictWarning.label "Mae'r dudalen hon wedi'i newid gan raglen arall, ond mae gennych hefyd newidiadau heb eu cadw yn y Cyfansoddwr.">
+<!ENTITY conflictResolve.label "Dewis pa fersiwn i'w chadw:">
+<!ENTITY keepCurrentPageButton.label "Cadw'r newidiadau cyfredol i'r dudalen">
+<!ENTITY useOtherPageButton.label "Newid y dudalen gyfredol gyda'r newidiadau eraill">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorButtonProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorButtonProperties.dtd
new file mode 100644
index 0000000000..adcfaeb2a7
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorButtonProperties.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Botwm">
+
+<!ENTITY Settings.label "Gosodiadau">
+
+<!ENTITY ButtonType.label "Math">
+<!ENTITY ButtonType.accesskey "t">
+<!ENTITY submit.value "Cyflwyno">
+<!ENTITY reset.value "Ailosod">
+<!ENTITY button.value "Botwm">
+
+<!ENTITY ButtonName.label "Enw:">
+<!ENTITY ButtonName.accesskey "E">
+<!ENTITY ButtonValue.label "Gwerth:">
+<!ENTITY ButtonValue.accesskey "G">
+<!ENTITY tabIndex.label "Mynegai Tab:">
+<!ENTITY tabIndex.accesskey "M">
+<!ENTITY ButtonDisabled.label "Anablwyd">
+<!ENTITY ButtonDisabled.accesskey "A">
+<!ENTITY AccessKey.label "Allwedd Mynediad:">
+<!ENTITY AccessKey.accesskey "A">
+
+<!ENTITY RemoveButton.label "Botwm Tynnu">
+<!ENTITY RemoveButton.accesskey "B">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorColorProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorColorProperties.dtd
new file mode 100644
index 0000000000..2dffbd577a
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorColorProperties.dtd
@@ -0,0 +1,29 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Lliwiau Tudalen a Chefndir">
+<!ENTITY pageColors.label "Lliwiau Tudalen">
+<!ENTITY defaultColorsRadio.label "Lliwiau Rhagosodedig y Darllenydd (Peidio gosod lliwiau ar y dudalen)">
+<!ENTITY defaultColorsRadio.accessKey "L">
+<!ENTITY defaultColorsRadio.tooltip "Defnyddio gosodiad lliw porwr y gwyliwr (darllenydd) yn unig">
+<!ENTITY customColorsRadio.label "Defnyddio lliwiau addasu:">
+<!ENTITY customColorsRadio.accessKey "D">
+<!ENTITY customColorsRadio.tooltip "Mae'r gosodiadau lliw hyn yn drech na gosodiadau'r porwr">
+
+<!ENTITY normalText.label "Testun arferol">
+<!ENTITY normalText.accessKey "T">
+<!ENTITY linkText.label "Testun dolen">
+<!ENTITY linkText.accessKey "d">
+<!ENTITY activeLinkText.label "Cyswllt testun gweithredol">
+<!ENTITY activeLinkText.accessKey "g">
+<!ENTITY visitedLinkText.label "Testun dolen wedi ymweld">
+<!ENTITY visitedLinkText.accessKey "o">
+<!ENTITY background.label "Cefndir:">
+<!ENTITY background.accessKey "e">
+<!ENTITY colon.character ":">
+<!ENTITY backgroundImage.label "Delweddau Cefndir:">
+<!ENTITY backgroundImage.accessKey "D">
+<!ENTITY backgroundImage.tooltip "Defnyddio ffeil delwedd fel cefndir ar gyfer eich tudalen">
+<!ENTITY backgroundImage.shortenedDataURI "URI data byrrach (bydd copi'n gosod yr URI llawn ar i'r clipfwrdd)">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorFieldSetProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorFieldSetProperties.dtd
new file mode 100644
index 0000000000..fa5baca70b
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorFieldSetProperties.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau'r Set Maes">
+
+<!ENTITY Legend.label "Mynegai">
+<!ENTITY Legend.accesskey "M">
+
+<!ENTITY EditLegendText.label "Golygu'r Mynegai:">
+<!ENTITY EditLegendText.accesskey "G">
+<!ENTITY LegendAlign.label "Alinio'r Mynegai:">
+<!ENTITY LegendAlign.accesskey "A">
+<!ENTITY AlignDefault.label "Rhagosodedig">
+<!ENTITY AlignLeft.label "Chwith">
+<!ENTITY AlignCenter.label "Canol">
+<!ENTITY AlignRight.label "De">
+
+<!ENTITY RemoveFieldSet.label "Tynnu'r Set Maes">
+<!ENTITY RemoveFieldSet.accesskey "T">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorFormProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorFormProperties.dtd
new file mode 100644
index 0000000000..e3b953b9f5
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorFormProperties.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau'r Ffurflen">
+
+<!ENTITY Settings.label "Gosodiadau">
+
+<!ENTITY FormName.label "Enw'r Ffurflen:">
+<!ENTITY FormName.accesskey "E">
+<!ENTITY FormAction.label "URL Gweithredol:">
+<!ENTITY FormAction.accesskey "U">
+<!ENTITY FormMethod.label "Dull:">
+<!ENTITY FormMethod.accesskey "D">
+<!ENTITY FormEncType.label "Amgodio:">
+<!ENTITY FormEncType.accesskey "A">
+<!ENTITY FormTarget.label "Ffrâm Darged:">
+<!ENTITY FormTarget.accesskey "F">
+
+<!ENTITY RemoveForm.label "Tynnu'r Ffurflen">
+<!ENTITY RemoveForm.accesskey "F">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorHLineProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorHLineProperties.dtd
new file mode 100644
index 0000000000..659a9ae24b
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorHLineProperties.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Priodweddau Llinell Lorweddol">
+
+<!ENTITY dimensionsBox.label "Dimensiynau">
+<!ENTITY heightEditField.label "Uchder:">
+<!ENTITY heightEditField.accessKey "U">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY pixelsPopup.value "picseli">
+<!ENTITY alignmentBox.label "Aliniad">
+<!ENTITY leftRadio.label "Chwith">
+<!ENTITY leftRadio.accessKey "C">
+<!ENTITY centerRadio.label "Canol">
+<!ENTITY centerRadio.accessKey "a">
+<!ENTITY rightRadio.label "De">
+<!ENTITY rightRadio.accessKey "D">
+
+<!ENTITY threeDShading.label "Gradd liwio 3-D">
+<!ENTITY threeDShading.accessKey "G">
+<!ENTITY saveSettings.label "Defnyddio fel Rhagosodiad">
+<!ENTITY saveSettings.accessKey "R">
+<!ENTITY saveSettings.tooltip "Cadw'r gosodiadau hyn i'w defnyddio wrth fewnosod llinellau llorweddol newydd">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorImageProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorImageProperties.dtd
new file mode 100644
index 0000000000..7026e9118f
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorImageProperties.dtd
@@ -0,0 +1,79 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- These strings are for use specifically in the editor's image and form image dialogs. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Priodweddau Delwedd">
+
+<!ENTITY pixelsPopup.value "picseli">
+<!-- These are in the Location tab panel -->
+
+<!ENTITY locationEditField.label "Lleoliad delwedd:">
+<!ENTITY locationEditField.accessKey "L">
+<!ENTITY locationEditField.tooltip "Teipio enw neu leoliad ffeil y ddelwedd">
+<!ENTITY locationEditField.shortenedDataURI "URI data byrrach (bydd copi'n gosod yr URI llawn ar i'r clipfwrdd)">
+<!ENTITY title.label "Cyngor:">
+<!ENTITY title.accessKey "C">
+<!ENTITY title.tooltip "Y briodoledd 'teitl' sy'n cael ei ddangos fel cyngor">
+<!ENTITY altText.label "Testun eiledol:">
+<!ENTITY altText.accessKey "e">
+<!ENTITY altTextEditField.tooltip "Teipio testun i'w arddangos yn lle'r ddelwedd">
+<!ENTITY noAltText.label "Peidio defnyddio testun eiledol">
+<!ENTITY noAltText.accessKey "P">
+
+<!ENTITY previewBox.label "Rhagolwg Delwedd">
+<!-- These controls are in the Dimensions tab panel -->
+<!-- actualSize.label should be same as actualSizeRadio.label + ":" -->
+
+<!ENTITY actualSize.label "Maint Gwirioneddol:">
+<!ENTITY actualSizeRadio.label "Maint Gwirioneddol">
+<!ENTITY actualSizeRadio.accessKey "M">
+<!ENTITY actualSizeRadio.tooltip "Dychwelyd i faint gwirioneddol y ddelwedd">
+<!ENTITY customSizeRadio.label "Maint Cyfaddasu">
+<!ENTITY customSizeRadio.accessKey "a">
+<!ENTITY customSizeRadio.tooltip "Newid maint y ddelwedd fel y'i dangosir ar y dudalen">
+<!ENTITY heightEditField.label "Uchder:">
+<!ENTITY heightEditField.accessKey "U">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY constrainCheckbox.label "Cyfyngu">
+<!ENTITY constrainCheckbox.accessKey "f">
+<!ENTITY constrainCheckbox.tooltip "Cadw cyfradd agwedd y ddelwedd">
+<!-- These controls are in the Image Map box of the expanded area -->
+
+<!ENTITY imagemapBox.label "Map Delwedd">
+<!ENTITY removeImageMapButton.label "Tynnu">
+<!ENTITY removeImageMapButton.accessKey "T">
+<!-- These are the options for image alignment -->
+
+<!ENTITY alignment.label "Alinio Testun i'r Ddelwedd">
+<!ENTITY bottomPopup.value "Ar y gwaelod">
+<!ENTITY topPopup.value "Ar y brig">
+<!ENTITY centerPopup.value "Yn y canol">
+<!ENTITY wrapRightPopup.value "Amlapio i'r dde">
+<!ENTITY wrapLeftPopup.value "Amlapio i'r chwith">
+<!-- These controls are in the Spacing Box -->
+
+<!ENTITY spacingBox.label "Bylchu">
+<!ENTITY leftRightEditField.label "Chwith a De:">
+<!ENTITY leftRightEditField.accessKey "h">
+<!ENTITY topBottomEditField.label "Brig a Gwaelod:">
+<!ENTITY topBottomEditField.accessKey "B">
+<!ENTITY borderEditField.label "Ymyl Solet:">
+<!ENTITY borderEditField.accessKey "Y">
+<!-- These controls are in the Link Box -->
+
+<!ENTITY showImageLinkBorder.label "Dangos ymyl o amgylch delwedd gysylltiedig">
+<!ENTITY showImageLinkBorder.accessKey "D">
+<!ENTITY LinkAdvancedEditButton.label "Dolen Golygu Uwch…">
+<!ENTITY LinkAdvancedEditButton.accessKey "D">
+<!ENTITY LinkAdvancedEditButton.tooltip "Ychwanegu neu newid Priodweddau HTML, priodoleddau arddulliau a JavaScript">
+<!-- These tabs are currently used in the image input dialog -->
+
+<!ENTITY imageInputTab.label "Ffurflen">
+<!ENTITY imageLocationTab.label "Lleoliad">
+<!ENTITY imageDimensionsTab.label "Dimensiynau">
+<!ENTITY imageAppearanceTab.label "Gwedd">
+<!ENTITY imageLinkTab.label "Dolen">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInputProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInputProperties.dtd
new file mode 100644
index 0000000000..9d837b3db9
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInputProperties.dtd
@@ -0,0 +1,50 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Maes Ffurflen">
+<!ENTITY windowTitleImage.label "Priodweddau Delwedd Ffurflen">
+
+<!ENTITY InputType.label "Math o Faes">
+<!ENTITY InputType.accesskey "M">
+<!ENTITY text.value "Testun">
+<!ENTITY password.value "Cyfrinair">
+<!ENTITY checkbox.value "Blwch Ticio">
+<!ENTITY radio.value "Botwm Radio">
+<!ENTITY submit.value "Botwm Cyflwyno">
+<!ENTITY reset.value "Botwm Ailgychwyn">
+<!ENTITY file.value "Ffeil">
+<!ENTITY hidden.value "Cuddiedig">
+<!ENTITY image.value "Delwedd">
+<!ENTITY button.value "Botwm">
+
+<!ENTITY InputSettings.label "Gosodiadau Maes">
+<!ENTITY InputName.label "Enw Maes:">
+<!ENTITY InputName.accesskey "E">
+<!ENTITY GroupName.label "Enw Grŵp:">
+<!ENTITY GroupName.accesskey "G">
+<!ENTITY InputValue.label "Gwerth Maes:">
+<!ENTITY InputValue.accesskey "w">
+<!ENTITY InitialValue.label "Gwerth Cychwynnol:">
+<!ENTITY InitialValue.accesskey "C">
+<!ENTITY InputChecked.label "Gwiriad Cyntaf">
+<!ENTITY InputChecked.accesskey "i">
+<!ENTITY InputSelected.label "Dewis Cyntaf">
+<!ENTITY InputSelected.accesskey "D">
+<!ENTITY InputReadOnly.label "Darllen yn unig">
+<!ENTITY InputReadOnly.accesskey "u">
+<!ENTITY InputDisabled.label "Anablwyd">
+<!ENTITY InputDisabled.accesskey "A">
+<!ENTITY tabIndex.label "Mynegai Tab:">
+<!ENTITY tabIndex.accesskey "M">
+<!ENTITY TextSize.label "Maint Maes:">
+<!ENTITY TextSize.accesskey "M">
+<!ENTITY TextLength.label "Hyd Mwyaf:">
+<!ENTITY TextLength.accesskey "H">
+<!ENTITY AccessKey.label "Allwedd Mynediad:">
+<!ENTITY AccessKey.accesskey "A">
+<!ENTITY Accept.label "Mathau Derbyn:">
+<!ENTITY Accept.accesskey "D">
+
+<!ENTITY ImageProperties.label "Priodweddau Delweddau…">
+<!ENTITY ImageProperties.accesskey "P">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInsertChars.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertChars.dtd
new file mode 100644
index 0000000000..494e858a23
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertChars.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Mewnosod Nod">
+<!ENTITY category.label "Categori">
+<!ENTITY letter.label "Llythyren:">
+<!ENTITY letter.accessKey "L">
+<!ENTITY character.label "Nod:">
+<!ENTITY character.accessKey "N">
+<!ENTITY accentUpper.label "Acen Priflythyren">
+<!ENTITY accentLower.label "Acen Llythyren fach">
+<!ENTITY otherUpper.label "Priflythyren Arall">
+<!ENTITY otherLower.label "Llythyren Fach Arall">
+<!ENTITY commonSymbols.label "Symbolau Cyffredin">
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY closeButton.label "Cau">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInsertMath.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertMath.dtd
new file mode 100644
index 0000000000..c3533186a1
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertMath.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod Mathemateg">
+
+<!ENTITY sourceEditField.label "Rhosi'r cod ffynhonnell LaTeX:">
+
+<!ENTITY options.label "Dewisiadau">
+<!ENTITY optionInline.label "Modd mewnlin">
+<!ENTITY optionInline.accesskey "m">
+<!ENTITY optionDisplay.label "Modd dangos">
+<!ENTITY optionDisplay.accesskey "d">
+<!ENTITY optionLTR.label "Cyfeiriad chwith i'r dde">
+<!ENTITY optionLTR.accesskey "c">
+<!ENTITY optionRTL.label "Cyfeiriad de i'r chwith">
+<!ENTITY optionRTL.accesskey "d">
+
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY insertButton.accesskey "M">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInsertSource.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertSource.dtd
new file mode 100644
index 0000000000..09877577a5
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertSource.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod HTML">
+<!ENTITY sourceEditField.label "Gosod tagiau HTML a thestun:">
+<!ENTITY example.label "Enghraifft: ">
+<!-- LOCALIZATION NOTE (exampleOpenTag.label): DONT_TRANSLATE: they are text for HTML tagnames: "<i>" and "</i>" -->
+<!ENTITY exampleOpenTag.label "&lt;i&gt;">
+<!-- LOCALIZATION NOTE (exampleCloseTag.label): DONT_TRANSLATE: they are text for HTML tagnames: "<i>" and "</i>" -->
+<!ENTITY exampleCloseTag.label "&lt;/i&gt;">
+<!ENTITY exampleText.label "Helo Pawb!">
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY insertButton.accesskey "M">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTOC.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTOC.dtd
new file mode 100644
index 0000000000..e30f42dfb2
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTOC.dtd
@@ -0,0 +1,16 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY Window.title        "Tabl Cynnwys">
+<!ENTITY buildToc.label      "Creu'r tabl cynnwys o:">
+<!ENTITY tag.label           "Tag:">
+<!ENTITY class.label         "Dosbarth:">
+<!ENTITY header1.label       "Lefel 1">
+<!ENTITY header2.label       "Lefel 2">
+<!ENTITY header3.label       "Lefel 3">
+<!ENTITY header4.label       "Lefel 4">
+<!ENTITY header5.label       "Lefel 5">
+<!ENTITY header6.label       "Lefel 6">
+<!ENTITY makeReadOnly.label  "Gwneud y tabl cynnwys yn darllen yn unig">
+<!ENTITY orderedList.label   "Rhifo pob cofnod yn y tabl cynnwys">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTable.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTable.dtd
new file mode 100644
index 0000000000..9a6acaa5f3
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorInsertTable.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod Tabl">
+
+<!ENTITY size.label "Maint">
+<!ENTITY numRowsEditField.label "Rhesi:">
+<!ENTITY numRowsEditField.accessKey "R">
+<!ENTITY numColumnsEditField.label "Colofnau:">
+<!ENTITY numColumnsEditField.accessKey "C">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY borderEditField.label "Ymyl:">
+<!ENTITY borderEditField.accessKey "Y">
+<!ENTITY borderEditField.tooltip "Teipio rhif ar gyfer ymyl y tabl, neu deipio sero (0) am ddim ymyl">
+<!ENTITY pixels.label "picseli">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorLabelProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorLabelProperties.dtd
new file mode 100644
index 0000000000..91eef16883
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorLabelProperties.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Label">
+
+<!ENTITY Settings.label "Gosodiadau">
+<!ENTITY Settings.accesskey "G">
+
+<!ENTITY EditLabelText.label "Golygu Testun:">
+<!ENTITY EditLabelText.accesskey "T">
+<!ENTITY LabelFor.label "Rheolaeth:">
+<!ENTITY LabelFor.accesskey "R">
+<!ENTITY AccessKey.label "Allwedd Mynediad:">
+<!ENTITY AccessKey.accesskey "A">
+
+<!ENTITY RemoveLabel.label "Tynnu Label">
+<!ENTITY RemoveLabel.accesskey "T">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorLinkProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorLinkProperties.dtd
new file mode 100644
index 0000000000..8f775351aa
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorLinkProperties.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Dolen">
+<!ENTITY LinkURLBox.label "Lleoliad Dolen">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorListProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorListProperties.dtd
new file mode 100644
index 0000000000..15216ed8a2
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorListProperties.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Rhestri Priodweddau">
+
+<!ENTITY ListType.label "Math Rhestr">
+<!ENTITY bulletStyle.label "Arddull Bwled:">
+<!ENTITY startingNumber.label "Cychwyn yn:">
+<!ENTITY startingNumber.accessKey "C">
+<!ENTITY none.value "Dim">
+<!ENTITY bulletList.value "Rhestr Bwled (Heb ei rhifo)">
+<!ENTITY numberList.value "Rhestr wedi'i Rhifo">
+<!ENTITY definitionList.value "Rhestr Ddiffinio">
+<!ENTITY changeEntireListRadio.label "Newid y rhestr i gyd">
+<!ENTITY changeEntireListRadio.accessKey "N">
+<!ENTITY changeSelectedRadio.label "Newid rhai eitemau yn unig">
+<!ENTITY changeSelectedRadio.accessKey "r">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorPageProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorPageProperties.dtd
new file mode 100644
index 0000000000..5f01194498
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorPageProperties.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Priodweddau Tudalen">
+<!ENTITY location.label "Lleoliad:">
+<!ENTITY lastModified.label "Newidiwyd Diwethaf:">
+<!ENTITY titleInput.label "Teitl:">
+<!ENTITY titleInput.accessKey "T">
+<!ENTITY authorInput.label "Awdur:">
+<!ENTITY authorInput.accessKey "A">
+<!ENTITY descriptionInput.label "Disgrifiad:">
+<!ENTITY descriptionInput.accessKey "D">
+<!ENTITY locationNewPage.label "[Tudalen newydd, heb ei chadw eto]">
+<!ENTITY EditHEADSource1.label "Defnyddiwr uwch:">
+<!ENTITY EditHEADSource2.label "I olygu cynnwys arall ardal &lt;head&gt; defnyddiwch &quot;HTML Source&quot; yn newislen Golwg neu Bar Offer Modd Golygu.">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorPersonalDictionary.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorPersonalDictionary.dtd
new file mode 100644
index 0000000000..615b0746e8
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorPersonalDictionary.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Geiriadur Personol">
+
+<!ENTITY wordEditField.label "Gair newydd:">
+<!ENTITY wordEditField.accessKey "n">
+<!ENTITY AddButton.label "Ychwanegu">
+<!ENTITY AddButton.accessKey "Y">
+<!ENTITY DictionaryList.label "Geiriau yn y geiriadur:">
+<!ENTITY DictionaryList.accessKey "G">
+<!ENTITY ReplaceButton.label "Newid">
+<!ENTITY ReplaceButton.accessKey "N">
+<!ENTITY RemoveButton.label "Tynnu">
+<!ENTITY RemoveButton.accessKey "y">
+
+<!ENTITY CloseButton.label "Cau">
+<!ENTITY CloseButton.accessKey "u">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorPublish.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorPublish.dtd
new file mode 100644
index 0000000000..90a45033a4
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorPublish.dtd
@@ -0,0 +1,65 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label            "Cyhoeddi Tudalen">
+<!ENTITY windowTitleSettings.label    "Gosodiadau Cyhoeddi">
+<!ENTITY publishTab.label             "Cyhoeddi">
+<!ENTITY settingsTab.label            "Gosodiadau">
+<!ENTITY publishButton.label          "Cyhoeddi">
+<!-- Publish Tab Panel -->
+
+<!ENTITY siteList.label               "Enw Gwefan:">
+<!ENTITY siteList.accesskey           "E">
+<!ENTITY siteList.tooltip             "Dewis y wefan rydych eisiau cyhoeddi iddi">
+<!ENTITY newSiteButton.label          "Gwefan Newydd">
+<!ENTITY newSiteButton.accesskey      "N">
+<!ENTITY docDirList.label             "Is gyfeiriadur gwefan y dudalen:">
+<!ENTITY docDirList.accesskey         "I">
+<!ENTITY docDirList.tooltip           "Dewis neu rhoi enw'r is gyfeiriadur ar gyfer y dudalen hon">
+<!ENTITY publishImgCheckbox.label     "Cynnwys delweddau a ffeiliau eraill">
+<!ENTITY publishImgCheckbox.accesskey "C">
+<!ENTITY publishImgCheckbox.tooltip   "Cyhoeddi delweddau a ffeiliau eraill cyfeiriwyd atynt gan y dudalen hon">
+<!ENTITY sameLocationRadio.label      "Defnyddio'r un lleoliad a'r dudalen">
+<!ENTITY sameLocationRadio.accesskey  "D">
+<!ENTITY sameLocationRadio.tooltip    "Cyhoeddi ffeiliau i'r un lleoliad â'r dudalen">
+<!ENTITY useSubdirRadio.label         "Defnyddio is gyfeiriadur y wefan:">
+<!ENTITY useSubdirRadio.accesskey     "e">
+<!ENTITY useSubdirRadio.tooltip       "Cyhoeddi ffeiliau i'r is gyfeiriadur pell">
+<!ENTITY otherDirList.tooltip         "Dewis neu rhoi enw'r is gyfeiriadur pell lle bydd y ffeiliau'n cael eu cyhoeddi">
+<!ENTITY pageTitle.label              "Teitl Tudalen:">
+<!ENTITY pageTitle.accesskey          "T">
+<!ENTITY pageTitle.tooltip            "Rhoi teitl i adnabod y dudalen yn y ffenestr ac yn y nodau tudalen">
+<!ENTITY pageTitleExample.label       "e.e.: &quot;Tudalen Gwe&quot;">
+<!ENTITY filename.label               "Enw Ffeil:">
+<!ENTITY filename.accesskey           "F">
+<!ENTITY filename.tooltip             "Rhoi enw ar gyfer y ffeil hon, gan gynnwys '.html' ar gyfer tudalen gwe">
+<!ENTITY filenameExample.label        "e.e,: &quot;tudalen.html&quot;">
+<!ENTITY setDefaultButton.label       "Gosod fel y Rhagosodiad">
+<!ENTITY setDefaultButton.accesskey   "R">
+<!ENTITY removeButton.label           "Tynnu Gwefan">
+<!ENTITY removeButton.accesskey       "T">
+<!-- Settings Tab Panel -->
+
+<!ENTITY publishSites.label           "Gwefannau Cyhoeddi">
+<!ENTITY serverInfo.label             "Gwybodaeth am y Gweinydd">
+<!ENTITY loginInfo.label              "Gwybodaeth Mewngofnodi">
+<!ENTITY siteName.label               "Enw Gwefan:">
+<!ENTITY siteName.accesskey           "E">
+<!ENTITY siteName.tooltip             "Llys Enw sy'n hysbysu'r wefan cyhoeddi (e.e.: 'Gwefan')">
+<!ENTITY siteUrl.label                "Cyfeiriad cyhoeddi (e.e.: 'ftp://ftp.fyisp.com/fyenwdefnyddiwr'):">
+<!ENTITY siteUrl.accesskey            "y">
+<!ENTITY siteUrl.tooltip              "Cyfeiriad FTP:// neu HTTP:// sy'n cael ei ddarparu gan eich ISP neu wasanaeth gwesteio">
+<!ENTITY browseUrl.label              "Cyfeiriad HTTP eich tudalen cartref (e.e.: 'http://www.fyisp.com/fyenwdefnyddiwr'):">
+<!ENTITY browseUrl.accesskey          "H">
+<!ENTITY browseUrl.tooltip            "Cyfeiriad HTTP:// eich cyfeiriadur cartref (peidiwch cynnwys yr enw ffeil)">
+<!ENTITY username.label               "Enw defnyddiwr:">
+<!ENTITY username.accesskey           "E">
+<!ENTITY username.tooltip             "Enw defnyddiwr i chi gael mewngofnodi i'ch gwasanaeth ISP neu westeio">
+<!ENTITY password.label               "Cyfrinair:">
+<!ENTITY password.accesskey           "C">
+<!ENTITY password.tooltip             "Cyfrinair sy'n gysylltiedig â'ch enw defnyddiwr">
+<!ENTITY savePassword.label           "Cadw'r Cyfrinair">
+<!ENTITY savePassword.accesskey       "a">
+<!ENTITY savePassword.tooltip         "Dewis hwn i gadw eich cyfrinair yn ddiogel gan ddefnyddio'r Rheolwr Cyfrineiriau">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorPublishProgress.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorPublishProgress.dtd
new file mode 100644
index 0000000000..ea85469390
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorPublishProgress.dtd
@@ -0,0 +1,16 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY siteUrl.label         "URL Gwefan:">
+<!ENTITY docSubdir.label       "Is gyfeiriadur tudalen:">
+<!ENTITY otherSubdir.label     "Is gyfeiriadur delwedd:">
+
+<!ENTITY status.label          "Cyhoeddi…">
+<!ENTITY fileList.label        "Statws Cyhoeddi">
+<!ENTITY succeeded.label       "Llwyddiant">
+<!ENTITY failed.label          "Methiant">
+
+<!ENTITY keepOpen              "Cadw'r ffenestr hwn ar agor wedi i'r cyhoeddi gwblhau.">
+<!ENTITY closeButton.label     "Cau">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorReplace.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorReplace.dtd
new file mode 100644
index 0000000000..b0cd9b5d97
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorReplace.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- extracted from EdReplace.xul -->
+
+
+<!ENTITY replaceDialog.title "Canfod a Newid">
+<!ENTITY findField.label "Canfod testun:">
+<!ENTITY findField.accesskey "C">
+<!ENTITY replaceField.label "Newid gyda:">
+<!ENTITY replaceField.accesskey "N">
+<!ENTITY caseSensitiveCheckbox.label "Cydweddu maint">
+<!ENTITY caseSensitiveCheckbox.accesskey "C">
+<!ENTITY wrapCheckbox.label "Amlapio">
+<!ENTITY wrapCheckbox.accesskey "A">
+<!ENTITY backwardsCheckbox.label "Chwilio nôl">
+<!ENTITY backwardsCheckbox.accesskey "h">
+<!ENTITY findNextButton.label "Canfod nesaf">
+<!ENTITY findNextButton.accesskey "n">
+<!ENTITY replaceButton.label "Newid">
+<!ENTITY replaceButton.accesskey "N">
+<!ENTITY replaceAndFindButton.label "Newid a Chanfod">
+<!ENTITY replaceAndFindButton.accesskey "N">
+<!ENTITY replaceAllButton.label "Newid Popeth">
+<!ENTITY replaceAllButton.accesskey "N">
+<!ENTITY closeButton.label "Cau">
+<!ENTITY closeButton.accesskey "C">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorSaveAsCharset.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorSaveAsCharset.dtd
new file mode 100644
index 0000000000..6bbde21b3b
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorSaveAsCharset.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- These strings are generic to all or most of the editor's dialogs. -->
+<!-- This button is for the progressive disclosure of additional editing functionality -->
+<!-- These strings are for use specifically in the editor's link dialog. -->
+
+
+
+<!ENTITY windowTitle2.label "Cadw a Newid Amgodiad Nod">
+<!ENTITY documentTitleTitle.label "Teitl y Dudalen">
+<!ENTITY documentCharsetTitle2.label "Amgodiad Testun">
+<!ENTITY documentCharsetDesc2.label "Dewis yr amgodiad testun rydych am cadw dogfen ynddi:">
+<!ENTITY documentExportToText.label "Allforio i Destun">
+
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorSelectProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorSelectProperties.dtd
new file mode 100644
index 0000000000..0d46e9b2af
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorSelectProperties.dtd
@@ -0,0 +1,48 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Rhestr Dewis">
+
+<!ENTITY Select.label "Rhestr Dewis">
+<!ENTITY SelectName.label "Enw Rhestr:">
+<!ENTITY SelectName.accesskey "E">
+<!ENTITY SelectSize.label "Uchder:">
+<!ENTITY SelectSize.accesskey "U">
+<!ENTITY SelectMultiple.label "Dewis Niferus">
+<!ENTITY SelectMultiple.accesskey "D">
+<!ENTITY SelectDisabled.label "Analluogwyd">
+<!ENTITY SelectDisabled.accesskey "A">
+<!ENTITY SelectTabIndex.label "Mynegai Tab:">
+<!ENTITY SelectTabIndex.accesskey "M">
+
+<!ENTITY OptGroup.label "Grŵp Dewis">
+<!ENTITY OptGroupLabel.label "Label:">
+<!ENTITY OptGroupLabel.accesskey "L">
+<!ENTITY OptGroupDisabled.label "Anablwyd">
+<!ENTITY OptGroupDisabled.accesskey "d">
+
+<!ENTITY Option.label "Dewis">
+<!ENTITY OptionText.label "Testun:">
+<!ENTITY OptionText.accesskey "T">
+<!ENTITY OptionValue.label "Gwerth:">
+<!ENTITY OptionValue.accesskey "G">
+<!ENTITY OptionSelected.label "Dewis Cyntaf">
+<!ENTITY OptionSelected.accesskey "D">
+<!ENTITY OptionDisabled.label "Anablwyd">
+<!ENTITY OptionDisabled.accesskey "A">
+
+<!ENTITY TextHeader.label "Testun">
+<!ENTITY ValueHeader.label "Gwerth">
+<!ENTITY SelectedHeader.label "Dewiswyd">
+
+<!ENTITY AddOption.label "Ychwanegu Dewis">
+<!ENTITY AddOption.accesskey "Y">
+<!ENTITY AddOptGroup.label "Ychwanegu Grŵp">
+<!ENTITY AddOptGroup.accesskey "Y">
+<!ENTITY RemoveElement.label "Tynnu">
+<!ENTITY RemoveElement.accesskey "T">
+<!ENTITY MoveElementUp.label "Symud i Fyny">
+<!ENTITY MoveElementUp.accesskey "F">
+<!ENTITY MoveElementDown.label "Symud i Lawr">
+<!ENTITY MoveElementDown.accesskey "L">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorSnapToGrid.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorSnapToGrid.dtd
new file mode 100644
index 0000000000..9c29d22f28
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorSnapToGrid.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Snapio i'r Grid">
+
+<!ENTITY enableSnapToGrid.label "galluogi Snapio i'r Grid">
+<!ENTITY enableSnapToGrid.accessKey "G">
+
+<!ENTITY sizeEditField.label "Maint:">
+<!ENTITY sizeEditField.accessKey "M">
+
+<!ENTITY pixelsLabel.value "picseli">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorSpellCheck.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorSpellCheck.dtd
new file mode 100644
index 0000000000..e33f37022f
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorSpellCheck.dtd
@@ -0,0 +1,38 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Gwirio Sillafu">
+
+<!ENTITY misspelledWord.label "Gair wedi'i gamsillafu:">
+<!ENTITY wordEditField.label "Newid gyda:">
+<!ENTITY wordEditField.accessKey "N">
+<!ENTITY checkwordButton.label "Gwirio Gair">
+<!ENTITY checkwordButton.accessKey "G">
+<!ENTITY suggestions.label "Awgrymiadau:">
+<!ENTITY suggestions.accessKey "A">
+<!ENTITY ignoreButton.label "Anwybyddu">
+<!ENTITY ignoreButton.accessKey "A">
+<!ENTITY ignoreAllButton.label "Anwybyddu Popeth">
+<!ENTITY ignoreAllButton.accessKey "P">
+<!ENTITY replaceButton.label "Amnewid">
+<!ENTITY replaceButton.accessKey "m">
+<!ENTITY replaceAllButton.label "Newid y Cyfan">
+<!ENTITY replaceAllButton.accessKey "y">
+<!ENTITY stopButton.label "Atal">
+<!ENTITY stopButton.accessKey "A">
+<!ENTITY userDictionary.label "Geiriadur Personol:">
+<!ENTITY moreDictionaries.label "Llwytho rhagor o eiriaduron i lawr…">
+<!ENTITY addToUserDictionaryButton.label "Ychwanegu Gair">
+<!ENTITY addToUserDictionaryButton.accessKey "G">
+<!ENTITY editUserDictionaryButton.label "Golygu…">
+<!ENTITY editUserDictionaryButton.accessKey "G">
+<!ENTITY recheckButton2.label "Ailwirio'r Testun">
+<!ENTITY recheckButton2.accessKey "T">
+<!ENTITY closeButton.label "Cau">
+<!ENTITY closeButton.accessKey "u">
+<!ENTITY sendButton.label "Anfon">
+<!ENTITY sendButton.accessKey "A">
+<!ENTITY languagePopup.label "Iaith:">
+<!ENTITY languagePopup.accessKey "I">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorTableProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorTableProperties.dtd
new file mode 100644
index 0000000000..456758cfa6
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorTableProperties.dtd
@@ -0,0 +1,75 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY tableWindow.title                "Priodoleddau Tabl">
+<!ENTITY applyButton.label                "Gosod">
+<!ENTITY applyButton.accesskey            "G">
+<!ENTITY closeButton.label                "Cau">
+<!ENTITY tableTab.label                   "Tabl">
+<!ENTITY cellTab.label                    "Celloedd">
+<!ENTITY tableRows.label                  "Rhesi:">
+<!ENTITY tableRows.accessKey              "R">
+<!ENTITY tableColumns.label               "Colofnau:">
+<!ENTITY tableColumns.accessKey           "C">
+<!ENTITY tableHeight.label                "Uchder:">
+<!ENTITY tableHeight.accessKey            "U">
+<!ENTITY tableWidth.label                 "Lled:">
+<!ENTITY tableWidth.accessKey             "L">
+<!ENTITY tableBorderSpacing.label         "Ymyl a Bylchiad">
+<!ENTITY tableBorderWidth.label           "Ymyl:">
+<!ENTITY tableBorderWidth.accessKey       "Y">
+<!ENTITY tableSpacing.label               "Bylchu:">
+<!ENTITY tableSpacing.accessKey           "B">
+<!ENTITY tablePadding.label               "Padin:">
+<!ENTITY tablePadding.accessKey           "P">
+<!ENTITY tablePxBetwCells.label           "picseli rhwng celloedd">
+<!ENTITY tablePxBetwBrdrCellContent.label "picseli rhwng border celloedd a'r cynnwys">
+<!ENTITY tableAlignment.label             "Aliniad y Tabl:">
+<!ENTITY tableAlignment.accessKey         "T">
+<!ENTITY tableCaption.label               "Pennawd:">
+<!ENTITY tableCaption.accessKey           "e">
+<!ENTITY tableCaptionAbove.label          "Uwchlaw'r Tabl">
+<!ENTITY tableCaptionBelow.label          "Islaw'r Tabl">
+<!ENTITY tableCaptionLeft.label           "Chwith y Tabl">
+<!ENTITY tableCaptionRight.label          "De'r tabl">
+<!ENTITY tableCaptionNone.label           "Dim">
+<!ENTITY tableInheritColor.label           "(Gadael i liw'r dudalen ddangos drwodd)">
+
+<!ENTITY cellSelection.label              "Dewis">
+<!ENTITY cellSelectCell.label             "Cell">
+<!ENTITY cellSelectRow.label              "Rhes">
+<!ENTITY cellSelectColumn.label           "Colofn">
+<!ENTITY cellSelectNext.label             "Nesaf">
+<!ENTITY cellSelectNext.accessKey         "N">
+<!ENTITY cellSelectPrevious.label         "Blaenorol">
+<!ENTITY cellSelectPrevious.accessKey     "B">
+<!ENTITY applyBeforeChange.label          "Bydd y newidiadau cyfredol yn cael eu gosod chyn newid y dewis.">
+<!ENTITY cellContentAlignment.label       "Aliniad Cynnwys">
+<!ENTITY cellHorizontal.label             "Llorweddol:">
+<!ENTITY cellHorizontal.accessKey         "L">
+<!ENTITY cellVertical.label               "Fertigol:">
+<!ENTITY cellVertical.accessKey           "F">
+<!ENTITY cellStyle.label                  "Arddull Cell:">
+<!ENTITY cellStyle.accessKey              "A">
+<!ENTITY cellNormal.label                 "Arferol">
+<!ENTITY cellHeader.label                 "Pennyn">
+<!ENTITY cellTextWrap.label               "Amlapio Testun:">
+<!ENTITY cellTextWrap.accessKey           "A">
+<!ENTITY cellWrap.label                   "Amlapio">
+<!ENTITY cellNoWrap.label                 "Peidio amlapio">
+<!ENTITY cellAlignTop.label               "Brig">
+<!ENTITY cellAlignMiddle.label            "Canol">
+<!ENTITY cellAlignBottom.label            "Gwaelod">
+<!ENTITY cellAlignJustify.label           "Unioni">
+<!ENTITY cellInheritColor.label           "(Gadael lliw'r tabl ddangos trwodd)">
+<!ENTITY cellUseCheckboxHelp.label        "Defnyddio blychau ticio i bennu pa briodweddau sy'n cael eu cymhwyso i bob un o'r celloedd">
+<!-- Used in both Table and Cell panels  -->
+
+<!ENTITY size.label                       "Maint">
+<!ENTITY pixels.label                     "picseli">
+<!ENTITY backgroundColor.label            "Lliw Cefndir:">
+<!ENTITY backgroundColor.accessKey        "L">
+<!ENTITY AlignLeft.label                  "Chwith">
+<!ENTITY AlignCenter.label                "Canol">
+<!ENTITY AlignRight.label                 "De">
diff --git a/l10n-cy/editor/ui/chrome/dialogs/EditorTextAreaProperties.dtd b/l10n-cy/editor/ui/chrome/dialogs/EditorTextAreaProperties.dtd
new file mode 100644
index 0000000000..9d1cb5605c
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/dialogs/EditorTextAreaProperties.dtd
@@ -0,0 +1,33 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau'r Ardal Testun">
+
+<!ENTITY Settings.label "Gosodiadau">
+
+<!ENTITY TextAreaName.label "Enw Maes:">
+<!ENTITY TextAreaName.accessKey "E">
+<!ENTITY TextAreaRows.label "Rhesi:">
+<!ENTITY TextAreaRows.accessKey "R">
+<!ENTITY TextAreaCols.label "Colofnau:">
+<!ENTITY TextAreaCols.accessKey "C">
+<!ENTITY TextAreaReadOnly.label "Darllen yn unig">
+<!ENTITY TextAreaReadOnly.accessKey "D">
+<!ENTITY TextAreaDisabled.label "Anablwyd">
+<!ENTITY TextAreaDisabled.accessKey "A">
+<!ENTITY TextAreaTabIndex.label "Mynegai Tab:">
+<!ENTITY TextAreaTabIndex.accessKey "M">
+<!ENTITY TextAreaAccessKey.label "Allwedd Mynediad:">
+<!ENTITY TextAreaAccessKey.accessKey "A">
+<!ENTITY InitialText.label "Testun Cychwynnol:">
+<!ENTITY InitialText.accessKey "T">
+
+<!ENTITY TextAreaWrap.label "Modd Amlapio:">
+<!ENTITY TextAreaWrap.accessKey "M">
+<!ENTITY WrapDefault.value "Rhagosodiad">
+<!ENTITY WrapOff.value "Diffodd">
+<!ENTITY WrapHard.value "Caled">
+<!ENTITY WrapSoft.value "Meddal">
+<!ENTITY WrapPhysical.value "Corfforol">
+<!ENTITY WrapVirtual.value "Rhithiol">
diff --git a/l10n-cy/editor/ui/chrome/region/region.properties b/l10n-cy/editor/ui/chrome/region/region.properties
new file mode 100644
index 0000000000..fb6fac676e
--- /dev/null
+++ b/l10n-cy/editor/ui/chrome/region/region.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# editor.js
+# editor.properties
+editor.throbber.url=http://www.seamonkey-project.org/
diff --git a/l10n-cy/mail/all-l10n.js b/l10n-cy/mail/all-l10n.js
new file mode 100644
index 0000000000..6e0520e894
--- /dev/null
+++ b/l10n-cy/mail/all-l10n.js
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#filter substitution
+
+pref("general.useragent.locale", "@AB_CD@");
+pref("spellchecker.dictionary", "@AB_CD@");
diff --git a/l10n-cy/mail/branding/thunderbird/brand.dtd b/l10n-cy/mail/branding/thunderbird/brand.dtd
new file mode 100644
index 0000000000..a809c8a566
--- /dev/null
+++ b/l10n-cy/mail/branding/thunderbird/brand.dtd
@@ -0,0 +1,13 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!ENTITY  brandShortName        "Thunderbird">
+<!ENTITY  brandShorterName      "Thunderbird">
+<!ENTITY  brandFullName         "Mozilla Thunderbird">
+<!-- LOCALIZATION NOTE (brandProductName):
+   This brand name can be used in messages where the product name needs to
+   remain unchanged across different versions (Daily, Beta, etc.). -->
+<!ENTITY  brandProductName      "Thunderbird">
+<!ENTITY  vendorShortName       "Mozilla">
+<!ENTITY  trademarkInfo.part1   "Mae Mozilla Thunderbird a logos Thunderbird yn
+                                  nodau masnachu'r Mozilla Foundation.">
diff --git a/l10n-cy/mail/branding/thunderbird/brand.ftl b/l10n-cy/mail/branding/thunderbird/brand.ftl
new file mode 100644
index 0000000000..52f2d38d59
--- /dev/null
+++ b/l10n-cy/mail/branding/thunderbird/brand.ftl
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Thunderbird Brand
+##
+## Thunderbird must be treated as a brand, and kept in English.
+## It cannot be:
+## - Transliterated.
+## - Translated.
+##
+## Reference: https://www.mozilla.org/styleguide/communications/translation/
+
+-brand-shorter-name = Thunderbird
+-brand-short-name = Thunderbird
+-brand-full-name = Mozilla Thunderbird
+# This brand name can be used in messages where the product name needs to
+# remain unchanged across different versions (Daily, Beta, etc.).
+-brand-product-name = Thunderbird
+-vendor-short-name = Mozilla
diff --git a/l10n-cy/mail/branding/thunderbird/brand.properties b/l10n-cy/mail/branding/thunderbird/brand.properties
new file mode 100644
index 0000000000..9dd5011219
--- /dev/null
+++ b/l10n-cy/mail/branding/thunderbird/brand.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+brandShortName=Thunderbird
+brandShorterName=Thunderbird
+brandFullName=Mozilla Thunderbird
+vendorShortName=Mozilla
diff --git a/l10n-cy/mail/chrome/communicator/utilityOverlay.dtd b/l10n-cy/mail/chrome/communicator/utilityOverlay.dtd
new file mode 100644
index 0000000000..f55398934e
--- /dev/null
+++ b/l10n-cy/mail/chrome/communicator/utilityOverlay.dtd
@@ -0,0 +1,47 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE : FILE This file contains the global menu items -->
+
+<!ENTITY fileMenu.label          "Ffeil">
+<!ENTITY fileMenu.accesskey        "F">
+<!ENTITY newMenu.label            "Newydd">
+<!ENTITY newMenu.accesskey          "N">
+
+<!ENTITY editMenu.label          "Golygu">
+<!ENTITY editMenu.accesskey        "G">
+<!ENTITY undoCmd.label            "Dadwneud">
+<!ENTITY undoCmd.accesskey          "u">
+<!ENTITY redoCmd.label            "Ailwneud">
+<!ENTITY redoCmd.accesskey          "A">
+<!ENTITY deleteCmd.label          "Dileu">
+<!ENTITY deleteCmd.accesskey        "D">
+<!ENTITY preferencesCmd2.label "Dewisiadau">
+<!ENTITY preferencesCmd2.accesskey "D">
+<!ENTITY preferencesCmdUnix.label       "Dewisiadau">
+<!ENTITY preferencesCmdUnix.accesskey     "D">
+
+<!ENTITY customizeCmd.label "Cyfaddasu">
+<!ENTITY customizeCmd.accesskey "f">
+
+<!ENTITY viewMenu.label          "Golwg">
+<!ENTITY viewMenu.accesskey        "l">
+<!ENTITY viewToolbarsMenu.label        "Barrau Offer">
+<!ENTITY viewToolbarsMenu.accesskey      "B">
+<!ENTITY showTaskbarCmd.label          "Bar Statws">
+<!ENTITY showTaskbarCmd.accesskey        "S">
+
+<!ENTITY closeCmd.label      "Cau">
+<!ENTITY closeCmd.key      "W">
+<!ENTITY closeCmd.accesskey    "u">
+
+<!ENTITY quitApplicationCmd.label  "Gadael">
+<!ENTITY quitApplicationCmd.key    "Q">
+<!ENTITY quitApplicationCmd.accesskey  "G">
+
+<!ENTITY quitApplicationCmdUnix.label  "Gadael">
+<!ENTITY quitApplicationCmdUnix.accesskey  "G">
+
+<!ENTITY quitApplicationCmdMac.label  "Gadael &brandShortName;">
+<!ENTITY quitApplicationCmdMac.accesskey  "G">
diff --git a/l10n-cy/mail/chrome/messenger-mapi/mapi.properties b/l10n-cy/mail/chrome/messenger-mapi/mapi.properties
new file mode 100644
index 0000000000..b85c9e9a31
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-mapi/mapi.properties
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Mail Integration Dialog
+dialogTitle=%S
+dialogText=Hoffech chi ddefnyddio %S fel eich rhaglen e-bost arferol?\u0020
+newsDialogText=Hoffech chi ddefnyddio %S fel eich rhaglen newyddion arferol?
+feedDialogText=Hoffech chi ddefnyddio %S fel eich casglwr llif arferol?
+checkboxText=Peidio dangos y deialog eto
+setDefaultMail=Nid yw %S wedi'i osod fel eich rhaglen e-bost rhagosodedig.  Hoffech chi ei gwneud yn rhaglen e-bost rhagosodedig?
+setDefaultNews=Nid yw %S wedi'i osod fel eich rhaglen newyddion rhagosodedig.  Hoffech chi ei gwneud yn rhaglen newyddion rhagosodedig?
+setDefaultFeed=Nid yw %S wedi ei osod fel eich rhaglen casglwr llif rhagosodedig.  Hoffech chi ei gwneud yn rhaglen casglwr llif rhagosodedig?
+alreadyDefaultMail=Mae %S eisoes wedi'i gosod fel eich rhaglen e-bost rhagosodedig.
+alreadyDefaultNews=Mae %S eisoes wedi'i gosod fel eich rhaglen newyddion rhagosodedig.
+alreadyDefaultFeed=Mae %S eisoes wedi'i gosod fel eich rhaglen casglwr llif rhagosodedig.
+
+# MAPI Messages
+loginText=Rhowch gyfrinair ar gyfer %S:
+loginTextwithName=Rhowch eich enw defnyddiwr a chyfrinair\u0020
+loginTitle=%S
+PasswordTitle=%S
+
+# MAPI Error Messages
+errorMessage=Nid oedd modd gosod %S fel y rhaglen e-bost rhagosodedig am nad oedd modd diweddaru allwedd yn y gofrestrfa. Gwiriwch gyda'ch gweinyddwr system fod gennych fynediad ysgrifennu i'r gofrestrfa ac yna ceisiwch eto.
+errorMessageNews=Nid oedd modd gosod %S fel y rhaglen newyddion rhagosodedig am nad oedd modd diweddaru allwedd yn y gofrestrfa. Gwiriwch gyda'ch gweinyddwr system fod gennych fynediad ysgrifennu i'r gofrestrfa ac yna ceisiwch eto.
+errorMessageTitle=%S
+
+# MAPI Security Messages
+mapiBlindSendWarning=Mae rhaglen arall yn ceisio anfon e-bost gan ddefnyddio eich proffil defnyddiwr. Ydych chi'n siŵr eich bod eisiau anfon e-bost?
+mapiBlindSendDontShowAgain=Rhybuddio pan fydd rhaglen arall yn ceisio anfon e-bost oddi wrthyf i
+
+#Default Mail Display String
+# localization note, %S is the vendor name
+defaultMailDisplayTitle=%S
+
diff --git a/l10n-cy/mail/chrome/messenger-newsblog/am-newsblog.dtd b/l10n-cy/mail/chrome/messenger-newsblog/am-newsblog.dtd
new file mode 100644
index 0000000000..f1167fa481
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-newsblog/am-newsblog.dtd
@@ -0,0 +1,14 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY biffAll.label                 "Galluogi diweddariad i bob llif">
+<!ENTITY biffAll.accesskey             "G">
+
+<!ENTITY newFeedSettings.label         "Y Gosodiadau Rhagosodedig i Lif Newydd">
+
+<!ENTITY manageSubscriptions.label     "Rheoli Tanysgrifiadau…">
+<!ENTITY manageSubscriptions.accesskey "T">
+
+<!ENTITY feedWindowTitle.label         "Dewin Cyfrif Llif">
+<!ENTITY feeds.accountName             "Blogiau a Llif Newyddion">
diff --git a/l10n-cy/mail/chrome/messenger-newsblog/feed-subscriptions.dtd b/l10n-cy/mail/chrome/messenger-newsblog/feed-subscriptions.dtd
new file mode 100644
index 0000000000..6f3a640ef9
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-newsblog/feed-subscriptions.dtd
@@ -0,0 +1,55 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Subscription Dialog -->
+<!ENTITY feedSubscriptions.label     "Tanysgrifiad Llif">
+<!ENTITY learnMore.label             "Dysgu rhagor am Llif">
+
+<!ENTITY feedTitle.label             "Teitl:">
+<!ENTITY feedTitle.accesskey         "T">
+
+<!ENTITY feedLocation.label          "URL Llif:">
+<!ENTITY feedLocation.accesskey      "L">
+<!ENTITY feedLocation2.placeholder   "Rhowch URL llif dilys">
+<!ENTITY locationValidate.label      "Dilysu">
+<!ENTITY validateText.label          "Gwirio dilysiad ac estyn url dilys.">
+
+<!ENTITY feedFolder.label            "Cadw erthyglau yn:">
+<!ENTITY feedFolder.accesskey        "e">
+
+<!-- Account Settings and Subscription Dialog -->
+<!ENTITY biffStart.label             "Gwirio am erthyglau newydd bob ">
+<!ENTITY biffStart.accesskey         "e">
+<!ENTITY biffMinutes.label           "munud">
+<!ENTITY biffMinutes.accesskey       "m">
+<!ENTITY biffDays.label              "diwrnod">
+<!ENTITY biffDays.accesskey          "d">
+<!ENTITY recommendedUnits.label      "Argymhelliad y cyhoeddwr:">
+
+<!ENTITY quickMode.label             "Dangos crynodeb erthygl yn lle llwytho tudalen gwe">
+<!ENTITY quickMode.accesskey         "c">
+
+<!ENTITY autotagEnable.label         "Creu tagiau'n awtomatig o enwau &lt;categorïau&gt; llif">
+<!ENTITY autotagEnable.accesskey     "a">
+<!ENTITY autotagUsePrefix.label      "Rhagosod tagiau gyda:">
+<!ENTITY autotagUsePrefix.accesskey  "R">
+<!ENTITY autoTagPrefix.placeholder   "Rhoi rhagosodiad tag">
+
+<!-- Subscription Dialog -->
+<!ENTITY button.addFeed.label        "Ychwanegu">
+<!ENTITY button.addFeed.accesskey    "Y">
+<!ENTITY button.verifyFeed.label     "Dilysu">
+<!ENTITY button.verifyFeed.accesskey "D">
+<!ENTITY button.updateFeed.label     "Diweddaru">
+<!ENTITY button.updateFeed.accesskey "D">
+<!ENTITY button.removeFeed.label     "Tynnu">
+<!ENTITY button.removeFeed.accesskey "T">
+<!ENTITY button.importOPML.label     "Mewnforio">
+<!ENTITY button.importOPML.accesskey "M">
+<!ENTITY button.exportOPML.label     "Allforio">
+<!ENTITY button.exportOPML.accesskey "A">
+<!ENTITY button.exportOPML.tooltip   "Allforiwch Llif gyda strwythur ffolderi; ctrl clic neu ctrl enter i allforio Llif fel rhestr">
+
+<!ENTITY cmd.close.commandKey        "w">
+<!ENTITY button.close.label          "Cau">
diff --git a/l10n-cy/mail/chrome/messenger-newsblog/newsblog.properties b/l10n-cy/mail/chrome/messenger-newsblog/newsblog.properties
new file mode 100644
index 0000000000..a3968ad0cd
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-newsblog/newsblog.properties
@@ -0,0 +1,93 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+subscribe-validating-feed=Dilysu'r llif…
+subscribe-cancelSubscription=Ydych chi'n siŵr eich bod am ddileu tanysgrifio i'r llif cyfredol?
+subscribe-cancelSubscriptionTitle=Tanysgrifio i Lif…
+subscribe-feedAlreadySubscribed=Mae gennych eisoes danysgrifiad i'r llif hwn.
+subscribe-errorOpeningFile=Methu agor y ffeil.
+subscribe-feedAdded=Wedi ychwanegu llif.
+subscribe-feedUpdated=Llif wedi ei ddiweddaru.
+subscribe-feedMoved=Tanysgrifiad llif wedi'i symud.
+subscribe-feedCopied=Wedi copïo tanysgrifiad llif.
+subscribe-feedRemoved=Dad-danysgrifio llif.
+subscribe-feedNotValid=Nid yw URL y llif yn ddilys.
+subscribe-feedVerified=Mae'r URL llif wedi ei ddilysu.
+subscribe-networkError=Nid oedd modd canfod URL y Llif. Gwiriwch yr enw a cheisio eto.
+subscribe-noAuthError=Nid yw'r URL llif wedi ei awdurdodi.
+subscribe-loading=Llwytho, arhoswch…
+
+subscribe-OPMLImportTitle=Dewis ffeil OPML i'w mewnforio
+## LOCALIZATION NOTE(subscribe-OPMLExportTitleList):
+## %S is the name of the feed account folder name.
+subscribe-OPMLExportTitleList=Allforio %S fel ffeil OPML- Rhestr Llif
+## LOCALIZATION NOTE(subscribe-OPMLExportTitleStruct):
+## %S is the name of the feed account folder name.
+subscribe-OPMLExportTitleStruct=Allforio %S fel ffeil OPML- Llif gyda strwythur ffolderi
+## LOCALIZATION NOTE(subscribe-OPMLExportFileDialogTitle):
+## %1$S is the brandShortName, %2$S is the name of the feed account folder name.
+subscribe-OPMLExportFileDialogTitle=%1$S Allforio OPML - %2$S
+## LOCALIZATION NOTE(subscribe-OPMLExportDefaultFileName):
+## %1$S is the brandShortName (Thunderbird for example), %2$S is the account name.
+## The default extension (.opml) is added here as it is not automatically appended in the file picker on MacOS.
+subscribe-OPMLExportDefaultFileName=My%1$SFeeds-%2$S.opml
+## LOCALIZATION NOTE(subscribe-OPMLImportInvalidFile): %S is the name of the OPML file the user tried to import.
+subscribe-OPMLImportInvalidFile=Nid yw ffeil %S i weld yn ffeil OPML dilys.
+## LOCALIZATION NOTE(subscribe-OPMLImportFeedCount): Semi-colon list of plural forms.
+## See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+## #1 is the count of new imported entries.
+subscribe-OPMLImportFeedCount=Heb fewnforio llifau newydd.;Mewnforiwyd #1 llif newydd.;Mewnforiwyd #1 llif newydd.;Mewnforiwyd #1 llif newydd.;Mewnforiwyd #1 llif newydd.;Mewnforiwyd #1 llif newydd.
+## LOCALIZATION NOTE(subscribe-OPMLImportUniqueFeeds): Semi-colon list of plural forms.
+## #1 is the count of new imported entries
+subscribe-OPMLImportUniqueFeeds=Mewnforiwyd #1 llif newydd nad ydych wedi tanysgrifio iddynt hyd yn hyn;Mewnforiwyd #1 llif newydd nad ydych wedi tanysgrifio iddynt hyd yn hyn
+## LOCALIZATION NOTE(subscribe-OPMLImportFoundFeeds):
+## #1 is total number of elements found in the file
+subscribe-OPMLImportFoundFeeds=(allan o #1 enghraifft a gafwyd);(allan o #1 enghraifft a gafwyd)
+## LOCALIZATION NOTE(subscribe-OPMLImportStatus):
+## This is the concatenation of the two strings defined above to compose 1 sentence.
+## %1$S = subscribe-OPMLImportUniqueFeeds
+## %2$S = subscribe-OPMLImportFoundFeeds
+subscribe-OPMLImportStatus=%1$S %2$S.
+
+subscribe-OPMLExportOPMLFilesFilterText=Ffeiliau OPML
+## LOCALIZATION NOTE(subscribe-OPMLExportDone): %S is the export file name.
+subscribe-OPMLExportDone=Mae llif o'r cyfrif hwn wedi eu hallforio i %S.
+
+subscribe-confirmFeedDeletionTitle=Tynnu Llif
+## LOCALIZATION NOTE(subscribe-confirmFeedDeletion): %S is the name of the feed the user wants to unsubscribe from.
+subscribe-confirmFeedDeletion=Ydych chi'n siŵr eich bod am ddad-danysgrifio o lif : \n %S?
+
+## LOCALIZATION NOTE(subscribe-gettingFeedItems):
+##  - The first %S is the number of articles processed so far;
+##  - The second %S is the total number of items
+subscribe-gettingFeedItems=Llwytho i lawr erthyglau llif (%S of %S)…
+
+newsblog-noNewArticlesForFeed=Nid oes erthyglau newydd i'r llif hwn.
+## LOCALIZATION NOTE(newsblog-networkError): %S is the feed URL
+newsblog-networkError=Nid oedd modd canfod %S. Gwiriwch yr enw a cheisio eto.
+## LOCALIZATION NOTE(newsblog-feedNotValid): %S is the feed URL
+newsblog-feedNotValid=Nid yw %S yn llif ddilys.
+## LOCALIZATION NOTE(newsblog-badCertError): %S is the feed URL host
+newsblog-badCertError=Mae %S yn defnyddio tystysgrif diogelwch annilys.
+## LOCALIZATION NOTE(newsblog-noAuthError): %S is the feed URL
+newsblog-noAuthError=Nid yw %S wedi ei awdurdodi.
+newsblog-getNewMsgsCheck=Gwirio'r llif am eitemau newydd…
+
+## LOCALIZATION NOTE(feeds-accountname): This string should be the same as feeds.accountName in am-newsblog.dtd
+feeds-accountname=Blogiau a Llif Newyddion
+
+## LOCALIZATION NOTE(externalAttachmentMsg): Content in the MIME part for external link attachments.
+externalAttachmentMsg=Mae'r atodiad MIME hwn wedi ei gadw ar wahân o'r neges.
+
+## Import wizard.
+ImportFeedsCreateNewListItem=* Cyfrif Newydd *
+ImportFeedsNewAccount=Creu a mewnforio i gyfrif Llif newydd
+ImportFeedsExistingAccount=Mewnforio i gyfrif Llif cyfredol
+## LOCALIZATION NOTE(ImportFeedsDone):
+##  - The first %S is the import file name;
+##  - The second %S is the value of either ImportFeedsNew or ImportFeedsExisting;
+##  - The third %S is the feed account name.
+ImportFeedsNew=newydd
+ImportFeedsExisting=cyfredol
+ImportFeedsDone=Mae mewnforio tanysgrifiadau llif wedi o ffeil %1$S i gyfrif %2$S '%3$S' wedi ei gwblhau.
diff --git a/l10n-cy/mail/chrome/messenger-region/region.properties b/l10n-cy/mail/chrome/messenger-region/region.properties
new file mode 100644
index 0000000000..a1c059d542
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-region/region.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Search engine order (order displayed in the search bar dropdown)s
+browser.search.order.1=Bing
+browser.search.order.2=Yahoo
+browser.search.order.3=
+
+# To make mapit buttons to disappear in the addressbook, specify empty string.  For example:
+# mail.addr_book.mapit_url.format=
+# The mail.addr_book.mapit_url.format should start with the URL of the mapping
+# service and then the query part with placeholders to be subsituted from values
+# from the addressbook contact's address.
+# Available placeholders are:
+# @A1 == address, part 1
+# @A2 == address, part 2
+# @CI == city
+# @ST == state
+# @ZI == zip code
+# @CO == country
+# Default map service:
+mail.addr_book.mapit_url.format=https://maps.google.com/maps?q=@A1%20@A2%20@CI%20@ST%20@ZI%20@CO
+# List of available map services (up to 5 can be defined here):
+mail.addr_book.mapit_url.1.name=Google Maps
+mail.addr_book.mapit_url.1.format=https://maps.google.com/maps?q=@A1%20@A2%20@CI%20@ST%20@ZI%20@CO
+mail.addr_book.mapit_url.2.name=OpenStreetMap
+mail.addr_book.mapit_url.2.format=https://nominatim.openstreetmap.org/search.php?polygon=1&q=@A1%2C@A2%2C@CI%2C@ST%2C@ZI%2C@CO
+
+mailnews.messageid_browser.url=http://groups.google.com/search?as_umsgid=%mid
+
+# Recognize non-standard versions of "Re:" in subjects from localized versions of MS Outlook et al.
+# Specify a comma-separated list without spaces. For example: mailnews.localizedRe=AW,SV
+mailnews.localizedRe=
diff --git a/l10n-cy/mail/chrome/messenger-smime/certFetchingStatus.dtd b/l10n-cy/mail/chrome/messenger-smime/certFetchingStatus.dtd
new file mode 100644
index 0000000000..6ab452d224
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/certFetchingStatus.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE shown while obtaining certificates from a directory -->
+
+
+<!ENTITY title.label "Llwytho Tystysgrifau i Lawr">
+<!ENTITY info.message "Chwilio'r cyfeiriadur am dystysgrifau derbynwyr. Gall hyn gymryd ychydig o funudau.">
+<!ENTITY stop.label "Atal y Chwilio">
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgCompSMIMEOverlay.dtd b/l10n-cy/mail/chrome/messenger-smime/msgCompSMIMEOverlay.dtd
new file mode 100644
index 0000000000..c2e4f7a94f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgCompSMIMEOverlay.dtd
@@ -0,0 +1,39 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgCompSMIMEOverlay.dtd UI for s/mime hooks in message composition -->
+
+<!ENTITY menu_securityDoNotEncrypt.label "Peidio ag Amgryptio">
+<!ENTITY menu_securityDoNotEncrypt.accesskey "P">
+
+<!-- not yet used
+<!ENTITY menu_securityEncryptOptional.label "Allow Encryption">
+<!ENTITY menu_securityEncryptOptional.accesskey "w">
+-->
+
+<!ENTITY menu_securityEncryptRequire2.label "Gofyn am Amgryptiad">
+<!ENTITY menu_securityEncryptRequire.accesskey "A">
+
+<!ENTITY menu_securitySign.label "Llofnodi'r Neges yn Ddigidol">
+<!ENTITY menu_securitySign.accesskey "L">
+
+<!ENTITY menu_securityAttachMyKey.label "Atodi fy Allwedd Gyhoeddus">
+<!ENTITY menu_securityAttachMyKey.accesskey "A">
+
+<!ENTITY menu_securityTech.label "Technoleg Amgryptio">
+<!ENTITY menu_securityTech.accesskey "T">
+
+<!ENTITY menu_techPGP.label "OpenPGP">
+<!ENTITY menu_techPGP.accesskey "O">
+<!ENTITY menu_techSMIME.label "S/MIME">
+<!ENTITY menu_techSMIME.accesskey "S">
+
+<!ENTITY menu_securityStatus.label "Gweld Gwybodaeth Diogelwch">
+<!ENTITY menu_securityStatus.accesskey "G">
+
+<!ENTITY securityButton.label "Diogelwch">
+<!ENTITY securityButton.tooltip "Gweld neu newid gosodiadau diogelwch">
+
+<!ENTITY menu_viewSecurityStatus.label "Gwybodaeth Diogelwch Neges">
+<!ENTITY menu_viewSecurityStatus.accesskey "D">
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.dtd b/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.dtd
new file mode 100644
index 0000000000..3c1dbc4285
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgCompSecurityInfo.dtd UI for viewing security status when composing a message -->
+
+
+<!ENTITY title.label "Diogelwch Neges">
+<!ENTITY subject.plaintextWarning "Sylw: Nid yw llinellau pwnc neges e-bost byth yn cael eu hamgryptio.">
+<!ENTITY status.heading "Bydd cynnwys eich neges yn cael ei hanfon fel a ganlyn:">
+<!ENTITY status.signed "Llofnod ddigidol:">
+<!ENTITY status.encrypted "Amgryptiad:">
+<!ENTITY status.certificates "Tystysgrifau:">
+<!ENTITY view.label "Golwg">
+<!ENTITY view.accesskey "l">
+<!ENTITY tree.recipient "Derbynnydd">
+<!ENTITY tree.status "Statws">
+<!ENTITY tree.issuedDate "Cyhoeddwyd">
+<!ENTITY tree.expiresDate "Daw i Ben">
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.properties b/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.properties
new file mode 100644
index 0000000000..e9e6e5b19e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgCompSecurityInfo.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+StatusNotFound=Heb Ganfod
+StatusValid=Dilys
+StatusExpired=Daeth i Ben
+StatusUntrusted=Dim Ymddiriedaeth
+StatusRevoked=Diddymwyd
+StatusInvalid=Annilys
+StatusYes=Iawn
+StatusNo=Na
+StatusNotPossible=Ddim yn bosib
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.dtd b/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.dtd
new file mode 100644
index 0000000000..42083b7e3f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgReadSMIMEOverlay.dtd UI for s/mime hooks in message reading -->
+
+
+<!ENTITY menu_securityStatus.label "Gwybodaeth Diogelwch Neges">
+<!ENTITY menu_securityStatus.accesskey "G">
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.properties b/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.properties
new file mode 100644
index 0000000000..90b8248152
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgReadSMIMEOverlay.properties
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+ImapOnDemand=Mae'r neges hon wedi ei llofnodi'n ddigidol, ond nid yw ei holl atodiadau wedi eu llwytho i lawr eto. Felly nid oes modd dilysu'r llofnod. Cliciwch Iawn i lwytho i lawr y neges gyflawn a dilysu'r llofnod.
+#
+#NOTE To translater, anything between %..% and <..> should not be translated.
+# the former will be replaced by java script, and the latter is HTML formatting.
+#
+CantDecryptTitle=Nid yw %brand% yn gallu dadgryptio'r neges hon
+CantDecryptBody=Mae'r anfonwr wedi amgryptio'r neges hon gan ddefnyddio un o'ch tystysgrifau digidol, er hynny, nid yw %brand% yn gallu dod o hyn i'r dystysgrif a'r allwedd breifat cyfatebol. <br> Atebion posib: <br><ul><li>Os oes gennych gerdyn clyfar, rhowch hwnnw i fewn. <li>Os ydych yn defnyddio peiriant newydd neu yn defnyddio proffil newydd %brand% , bydd angen i chi adfer eich tystysgrif a'ch allwedd breifat o gopi wrth gefn. Mae copïau wrth gefn o dystysgrifau yn gorffen gyda ".p12".</ul>\u0020
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgReadSecurityInfo.dtd b/l10n-cy/mail/chrome/messenger-smime/msgReadSecurityInfo.dtd
new file mode 100644
index 0000000000..26c71b0c26
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgReadSecurityInfo.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgReadSecurityInfo.dtd UI for viewing security status when reading a received message -->
+
+<!ENTITY status.label "Diogelwch Neges">
+<!ENTITY signatureCert.label "Gweld Llofneo Tystysgrif">
+<!ENTITY encryptionCert.label "Gweld Tystysgrif Amgryptio">
+
+<!ENTITY signer.name "Llofnod gan:">
+<!ENTITY recipient.name "Amgryptio ar gyfer:">
+<!ENTITY email.address "Cyfeiriad e-bost:">
+<!ENTITY issuer.name "Tystysgrif wedi'i ryddhau gan:">
+
+<!-- LOCALIZATION NOTE(SMIME.label): This a name for a technical standard. You should not translate it, but if applicable, you may write it using localized characters. -->
+<!ENTITY SMIME.label "S/MIME">
diff --git a/l10n-cy/mail/chrome/messenger-smime/msgSecurityInfo.properties b/l10n-cy/mail/chrome/messenger-smime/msgSecurityInfo.properties
new file mode 100644
index 0000000000..bd835d11c2
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger-smime/msgSecurityInfo.properties
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## Signature Information strings
+SINoneLabel=Nid oes gan y Neges Dystysgrif Ddigidol
+SINone=Nid yw'r neges yn cynnwys llofnod digidol yr anfonwr. Mae absenoldeb y llofnod digidol yn golygu bod modd i'r neges ddod gan rywun sy'n cogio mai ei gyfeiriad e-bost yw hwn. Mae hefyd yn bosibl fod y neges wedi cael ei newid wrth deithio ar draws y rhwydwaith. Er hynny, mae'n annhebygol fod yr un o'r ddau wedi digwydd.
+SIValidLabel=Mae'r Neges wedi'i Llofnodi
+SIValid=Mae'r neges yn cynnwys llofnod digidol dilys. Nid yw'r neges wedi'i newid ers iddi gael ei hanfon.
+SIInvalidLabel=Nid yw'r Llofnod Digidol yn Ddilys
+SIInvalidHeader=Mae'r neges yn cynnwys llofnod digidol, ond mae'r llofnod yn annilys.
+SIContentAltered=Nid yw'r llofnod yn cydweddu'n union â chynnwys y neges. Mae'n ymddangos fod y neges wedi'i newid ar ôl i'r anfonwr ei llofnod. Peidiwch ymddiried yn nilysrwydd y neges cyn gwirio ei gynnwys gyda'r anfonwr.
+SIExpired=Mae'n ymddangos bod y dystysgrif gafodd ei defnyddio i lofnodi'r neges wedi dod i ben. Gwnewch yn siŵr bod cloc eich cyfrifiadur wedi'i osod yn gywir.
+SIRevoked=Mae'r dystysgrif sydd wedi ei defnyddio i lofnodi'r neges wedi'i ddiddymu. Peidiwch ymddiried yn nilysrwydd y neges nes i chi wirio'r cynnwys gyda'r anfonwr.
+SINotYetValid=Nid yw'r dystysgrif sydd wedi'i defnyddio i lofnodi'r neges yn ymddangos yn ddilys. Gwnewch yn siŵr fod eich cloc wedi ei osod yn gywir.
+SIUnknownCA=Mae'r dystysgrif gafodd ei defnyddio i lofnodi'r neges wedi'i chyhoeddi gan awdurdod tystysgrif anhysbys.
+SIUntrustedCA=Mae'r dystysgrif gafodd ei defnyddio i lofnodi'r neges wedi'i chyhoeddi gan awdurdod tystysgrif nad ydych yn ymddiried ynddo i gyhoeddi'r math yma o dystysgrif.
+SIExpiredCA=Mae'r dystysgrif rydych yn ei defnyddio i lofnodi'r neges wedi'i chyhoeddi gan awdurdod tystysgrif mae eu tystysgrif wedi dod i ben. Gwnewch yn siŵr fod cloc eich cyfrifiadur wedi ei osod yn gywir.
+SIRevokedCA=Mae'r dystysgrif a ddefnyddiwyd i lofnodi'r neges wedi'i chyhoeddi gan awdurdod tystysgrif y mae ei dystysgrif ei hun wedi ei ddiddymu. Peidiwch ymddiried yn nilysrwydd y neges cyn gwirio ei gynnwys gyda'r anfonwr.
+SINotYetValidCA=Cafodd y dystysgrif a ddefnyddiwyd i lofnodi'r neges ei chyhoeddi gan awdurdod tystysgrif nad yw eu tystysgrif eto'n ddilys. Gwnewch yn siŵr fod eich cloc wedi'i osod yn gywir.
+SIInvalidCipher=Mae'r neges wedi'i llofnodi gan ddefnyddio cryfder amgryptio nad yw'r fersiwn hwn o'ch meddalwedd yn ei gynnal.
+SIClueless=Mae anawsterau anhysbys i'r llofnod digidol hwn. Peidiwch ymddiried yn nilysrwydd y neges nes i chi wirio ei chynnwys gyda'r anfonwr.
+SIPartiallyValidLabel=Neges wedi'i llofnodi
+SIPartiallyValidHeader=Er bod y llofnod digidol yn ddilys, mae'n anhysbys os yw'r anfonwr a'r llofnod yr un.
+SIHeaderMismatch=Mae'r cyfeiriad e-bost nodwyd yn nhystysgrif y llofnodwr yn wahanol i'r cyfeiriad e-bost a ddefnyddiwyd i anfon y neges. Edrychwch ar fanylion y dystysgrif llofnod i weld pwy wnaeth lofnodi'r neges.
+SICertWithoutAddress=Nid yw'r dystysgrif a ddefnyddiwyd i lofnodi'r neges yn cynnwys cyfeiriad e-bost. Edrychwch ar fanylion y dystysgrif llofnod i weld pwy wnaeth ei llofnodi.
+
+## Encryption Information strings
+EINoneLabel2=Nid yw'r Neges wedi'i Hamgryptio
+EINone=Nid yw'r neges hon wedi'i hamgryptio cyn ei hanfon. Mae modd i eraill weld negeseuon sy'n cael eu hanfon ar draws y rhyngrwyd ac sydd heb eu hamgryptio.
+EIValidLabel=Mae'r Neges wedi'i Hamgryptio
+EIValid=Cafodd y neges ei hamgryptio cyn ei hanfon atoch. Mae amgryptio'n ei gwneud yn anodd iawn i bobl eraill edrych ar wybodaeth wrth iddo deithio ar draws y rhwydwaith.
+EIInvalidLabel=Nid Oes Modd Dadgryptio'r Neges
+EIInvalidHeader=Mae'r neges wedi'i hamgryptio cyn ei hanfon atoch, ond nid oes modd ei dadgryptio.
+EIContentAltered=Mae'n ymddangos bod cynnwys y neges wedi'i newid yn ystod y trosglwyddiad.
+EIClueless=Mae yna anawsterau anhysbys gyda'r neges wedi'i hamgryptio.
diff --git a/l10n-cy/mail/chrome/messenger/AccountManager.dtd b/l10n-cy/mail/chrome/messenger/AccountManager.dtd
new file mode 100644
index 0000000000..e41d1753ca
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/AccountManager.dtd
@@ -0,0 +1,37 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from AccountManager.xhtml -->
+
+<!ENTITY accountManagerTitle.label "Gosodiadau'r Cyfrif">
+<!ENTITY  accountManagerCloseButton.label "Cau">
+
+<!ENTITY accountActionsButton.label "Gweithredoedd Cyfrif">
+<!ENTITY accountActionsButton.accesskey "G">
+<!ENTITY addMailAccountButton.label "Ychwanegu Cyfrif E-bost…">
+<!ENTITY addMailAccountButton.accesskey "E">
+<!ENTITY addIMAccountButton.label "Ychwanegu Cyfrif Sgwrsio…">
+<!ENTITY addIMAccountButton.accesskey "S">
+<!ENTITY addFeedAccountButton.label "Ychwanegu Cyfrif Llif…">
+<!ENTITY addFeedAccountButton.accesskey "L">
+<!ENTITY addOtherAccountButton.label "Ychwanegu Cyfrif Arall…">
+<!ENTITY addOtherAccountButton.accesskey "A">
+<!ENTITY setDefaultButton.label "Gosod fel y Rhagosodiad">
+<!ENTITY setDefaultButton.accesskey "R">
+<!ENTITY removeButton.label "Tynnu Cyfrif">
+<!ENTITY removeButton.accesskey "T">
+
+<!ENTITY addonsButton.label "Estyniadau a Themâu">
+
+<!-- AccountManager.xhtml -->
+<!-- LOCALIZATION NOTE : this is part of an inline-style attribute on the account
+     setting dialog, which specifies the width and height in em units of the dialog.
+     Localizers ONLY can increase these widths if they are having difficulty getting
+     panel content to fit.
+     1ch = The width of the "0" (ZERO, U+0030) glyph for the current font.
+     1em = The height of the font.
+     XUL/FE DEVELOPERS: DO NOT MODIFY THIS VALUE. It represents the correct size of
+     this window for en-US. -->
+<!ENTITY accountManager.size "width: 105ch; height: 55em;">
+<!ENTITY accountTree.width "width: 32ch;">
diff --git a/l10n-cy/mail/chrome/messenger/AccountWizard.dtd b/l10n-cy/mail/chrome/messenger/AccountWizard.dtd
new file mode 100644
index 0000000000..4de0a346ec
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/AccountWizard.dtd
@@ -0,0 +1,128 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Entities for AccountWizard -->
+
+<!ENTITY windowTitle.label "Dewin Cyfrif">
+<!ENTITY accountWizard.size "width: 40em; height: 38em;">
+
+<!-- Entities for Account Type page -->
+
+<!ENTITY accountSetupInfo2.label "Er mwyn derbyn negeseuon, rhaid yn gyntaf, greu cyfrif.">
+<!ENTITY accountTypeTitle.label "Creu Cyfrif Newydd">
+<!ENTITY accountTypeDesc2.label "Bydd y Dewin yn casglu'r wybodaeth angenrheidiol i greu cyfrif E-bost neu Grŵp Newyddion. Os nad oes gennych y wybodaeth angenrheidiol, cysylltwch â'ch Gweinyddwr System neu Ddarparwr Gwasanaeth Rhyngrwyd.">
+<!ENTITY accountTypeDirections.label "Dewiswch y math o gyfrif i'w greu:">
+<!ENTITY accountTypeMail.label "Cyfrif e-bost">
+<!ENTITY accountTypeMail.accesskey "e">
+<!ENTITY accountTypeNews.label "Cyfrif Grŵp Newyddion">
+<!ENTITY accountTypeNews.accesskey "G">
+
+<!-- LOCALIZATION NOTE(accountTypeMovemail.label): do not translate 'Movemail' -->
+<!ENTITY accountTypeMovemail.label "Unix Mailspool (Movemail)">
+<!ENTITY accountTypeMovemail.accesskey "U">
+
+<!-- Entities for Identity page -->
+
+<!ENTITY identityTitle.label "Hunaniaeth">
+<!ENTITY identityDesc.label "Mae gan bob cyfrif enw, sef y wybodaeth sy'n eich enwi i eraill sy'n derbyn negeseuon gennych.">
+
+<!-- LOCALIZATION NOTE (fullnameDesc.label) : do not translate two of "&quot;" in below line -->
+<!ENTITY fullnameDesc.label "Rhowch yr enw yr hoffech iddo ymddangos ym maes &quot;Oddi wrth&quot; y negeseuon fyddwch yn eu hanfon">
+<!-- LOCALIZATION NOTE (fullnameExample.label) : use following directions for below line
+  1, do not translate two of "&quot;"
+  2, Use localized full name instead of "John Smith"
+-->
+<!ENTITY fullnameExample.label "(er enghraifft., &quot;John Jones&quot;).">
+<!ENTITY fullnameLabel.label "Eich Enw:">
+<!ENTITY fullnameLabel.accesskey "E">
+
+<!ENTITY emailLabel.label "Cyfeiriad E-bost:">
+<!ENTITY emailLabel.accesskey "b">
+
+<!-- Entities for Incoming Server page -->
+
+<!ENTITY incomingTitle.label "Gwybodaeth Gweinydd Derbyn">
+<!ENTITY incomingServerTypeDesc.label "Dewiswch y math o weinydd derbyn rydych yn ei ddefnyddio.">
+<!-- LOCALIZATION NOTE (imapType.label) : Do not translate "IMAP" in below line -->
+<!ENTITY imapType.label "IMAP">
+<!ENTITY imapType.accesskey "I">
+<!-- LOCALIZATION NOTE (popType.label) : Do not translate "POP" in below line -->
+<!ENTITY popType.label "POP">
+<!ENTITY popType.accesskey "P">
+<!ENTITY leaveMsgsOnSrvr.label "Gadael negeseuon ar y gweinydd">
+<!ENTITY leaveMsgsOnSrvr.accesskey "a">
+<!ENTITY portNum.label "Porth:">
+<!ENTITY portNum.accesskey "P">
+<!ENTITY defaultPortLabel.label "Rhagosodiad:">
+<!ENTITY defaultPortValue.label "">
+<!-- LOCALIZATION NOTE (incomingServerNameDesc.label) : Do not translate "&quot;pop.example.net&quot;" in below line -->
+<!ENTITY incomingServer.description "Rhowch enw eich gweinydd derbyn (e.e., &quot;ebost.esiampl.net&quot;).">
+<!ENTITY incomingServer.label "Gweinydd Derbyn:">
+<!ENTITY incomingServer.accesskey "G">
+<!-- LOCALIZATION NOTE (incomingUsername.description) : do not translate "&quot;jsmith&quot;" in below line -->
+<!ENTITY incomingUsername.description "Rhowch yr enw derbyn roddwyd i chi gan eich darparwr e-bost (e.e. &quot;jjones&quot;).">
+<!ENTITY incomingUsername.label "Enw Defnyddiwr:">
+<!ENTITY incomingUsername.accesskey "D">
+<!-- LOCALIZATION NOTE (newsServerNameDesc.label) : Do not translate "NNTP" or the "&quot;" entities in below line -->
+<!ENTITY newsServerNameDesc.label "Rhowch enw eich gweinydd newyddion (NNTP). (e.e., &quot;news.esiampl.net&quot;).">
+<!ENTITY newsServerLabel.label "Gweinydd Grŵp Newyddion:">
+<!ENTITY newsServerLabel.accesskey "G">
+
+<!-- Entities for Outgoing Server page -->
+
+<!ENTITY outgoingTitle.label "Gwybodaeth Gweinydd Anfon">
+<!-- LOCALIZATION NOTE (outgoingServer.description) : Do not translate "SMTP" and "&quot;smtp.example.net&quot;" in below line -->
+<!ENTITY outgoingServer.description "Rhowch enw&apos;r gweinydd anfon rhoddwyd i chi gan eich darparwr e-bost (SMTP) (e.e, &quot;smtp.esiampl.net&quot;).">
+<!ENTITY outgoingServer.label "Gweinydd Anfon:">
+<!ENTITY outgoingServer.accesskey "A">
+<!ENTITY outgoingUsername.description "Rhowch yr enw defnyddiwr anfon rhoddwyd i chi gan eich darparwr e-bost (fel rheol yr un a'ch enw defnyddiwr derbyn).">
+<!ENTITY outgoingUsername.label "Enw Defnyddiwr Anfon:">
+<!ENTITY outgoingUsername.accesskey "A">
+
+<!-- LOCALIZATION NOTE (modifyOutgoing.suffix) : This string will be appended after each of
+     haveSmtp1.suffix3, haveSmtp2.suffix3, haveSmtp3.suffix3 .
+-->
+<!ENTITY modifyOutgoing.suffix "Mae modd newid y gweinyddion anfon yn y gosodiadau cyfrif.">
+<!-- LOCALIZATION NOTE (haveSmtp1.prefix and haveSmtp1.suffix3) : Do not translate "SMTP" and "&quot;" in
+     these variables. Also, translate haveSmtp1.prefix and haveSmtp1.suffix3 as a single sentence, inserting
+     text after the "&quot;" entity in haveSmtp1.suffix3, if required grammatically.
+-->
+<!ENTITY haveSmtp1.prefix "Bydd eich gweinydd anfon cyfredol (SMTP), &quot;">
+<!ENTITY haveSmtp1.suffix3 "&quot;, yn cael ei ddefnyddio.">
+<!-- LOCALIZATION NOTE (haveSmtp2.prefix and haveSmtp2.suffix3) : Do not translate "SMTP" and "&quot;" in
+     these variables. Also, translate haveSmtp2.prefix and haveSmtp2.suffix3 as a single sentence, inserting
+     text after the "&quot;" entity in haveSmtp2.suffix3, if required grammatically.
+-->
+<!ENTITY haveSmtp2.prefix "Bydd eich gweinydd anfon cyfredol (SMTP), &quot;">
+<!ENTITY haveSmtp2.suffix3 "&quot;, yn cael ei ddefnyddio.">
+<!-- LOCALIZATION NOTE (haveSmtp3.prefix and haveSmtp3.suffix3) : Do not translate "SMTP" and "&quot;" in
+     these variables. Also, translate haveSmtp3.prefix and haveSmtp3.suffix3 as a single sentence, inserting
+     text after the "&quot;" entity in haveSmtp3.suffix3, if required grammatically.
+-->
+<!ENTITY haveSmtp3.prefix "Mae eich gweinydd anfon (SMTP), &quot;">
+<!ENTITY haveSmtp3.suffix3 "&quot;, yr un peth â&apos;ch gweinydd derbyn, bydd eich enw defnyddiwr i mewn yn cael ei ddefnyddio i gael mynediad ato.">
+
+<!-- Entities for Account name page -->
+
+<!ENTITY accnameTitle.label "Enw Cyfrif">
+<!-- LOCALIZATION NOTE (accnameDesc.label) : do not translate any "&quot;" in below line -->
+<!ENTITY accnameDesc.label "Rhowch yr enw yr hoffech gyfeirio at y cyfrif. (e.e. &quot;Cyfrif Gwaith&quot;, &quot;Cyfrif Cartref&quot; neu &quot;Cyfrif Newyddion&quot;).">
+<!ENTITY accnameLabel.label "Enw Cyfrif:">
+<!ENTITY accnameLabel.accesskey "E">
+
+<!-- Entities for Done (Congratulations) page -->
+
+<!ENTITY completionTitle.label "Llongyfarchiadau!">
+<!ENTITY completionText.label "Rydych wedi rhoi'r holl wybodaeth angenrheidiol ar gyfer creu'r cyfrif.">
+<!ENTITY serverTypePrefix.label "Math o Weinydd Derbyn:">
+<!ENTITY serverNamePrefix.label "Enw'r Gweinydd Derbyn:">
+<!ENTITY smtpServerNamePrefix.label "Enw'r Gweinydd Anfon (SMTP):">
+<!ENTITY newsServerNamePrefix.label "Enw Gweinydd Grwpiau Newyddion (NNTP):">
+<!ENTITY downloadOnLogin.label "Llwytho negeseuon i lawr nawr">
+<!ENTITY downloadOnLogin.accesskey "L">
+<!ENTITY deferStorageDesc.label "Dad-diciwch y blwch ticio i gadw e-byst ar gyfer y cyfrif hwn yn ei gyfeiriadur ei hun. Bydd hynny'n gwneud i'r cyfrif ymddangos fel cyfrif lefel uchel. Fel arall, bydd yn rhan o'r cyfrif Derbyn Eang Ffolderi Lleol.">
+<!ENTITY deferStorage.label "Defnyddiwch Flwch Derbyn Eang (cadw e-byst mewn Ffolderi Lleol)">
+<!ENTITY deferStorage.accesskey "D">
+<!ENTITY clickFinish.label "Cliciwch Gorffen i gadw'r gosodiadau a gadael y Dewin Cyfrif.">
+<!ENTITY clickFinish.labelMac "Cliciwch Gorffen i gadw'r gosodiadau a gadael y Dewin Cyfrif.">
diff --git a/l10n-cy/mail/chrome/messenger/CustomHeaders.dtd b/l10n-cy/mail/chrome/messenger/CustomHeaders.dtd
new file mode 100644
index 0000000000..f2167621cc
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/CustomHeaders.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title "Cyfaddasu Penynnau">
+<!ENTITY addButton.label "Ychwanegu">
+<!ENTITY addButton.accesskey "a">
+<!ENTITY removeButton.label "Tynnu">
+<!ENTITY removeButton.accesskey "T">
+<!ENTITY newMsgHeader.label "Pennyn neges newydd:">
+<!ENTITY newMsgHeader.accesskey "P">
diff --git a/l10n-cy/mail/chrome/messenger/FilterEditor.dtd b/l10n-cy/mail/chrome/messenger/FilterEditor.dtd
new file mode 100644
index 0000000000..6c186215fa
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/FilterEditor.dtd
@@ -0,0 +1,68 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title "Rheolau Hidlo">
+<!ENTITY filterEditorDialog.dimensions "width: 100ch;">
+<!ENTITY filterName.label "Enw'r hidl:">
+<!ENTITY filterName.accesskey "E">
+
+<!ENTITY junk.label "Sbam">
+<!ENTITY notJunk.label "Nid Sbam">
+
+<!ENTITY lowestPriorityCmd.label "Isaf">
+<!ENTITY lowPriorityCmd.label "Isel">
+<!ENTITY normalPriorityCmd.label "Arferol">
+<!ENTITY highPriorityCmd.label "Uchel">
+<!ENTITY highestPriorityCmd.label "Uchaf">
+
+<!ENTITY contextDesc.label "Gosod yr hidl pan yn:">
+<!ENTITY contextIncomingMail.label "Estyn E-bost Newydd:">
+<!ENTITY contextIncomingMail.accesskey "E">
+<!ENTITY contextManual.label "Rhedeg â Llaw">
+<!ENTITY contextManual.accesskey "L">
+<!ENTITY contextBeforeCls.label "Hidlo cyn Dynodi fel Sbam">
+<!ENTITY contextAfterCls.label "Hidlo ar ôl Dynodi fel Sbam">
+<!ENTITY contextOutgoing.label "Ar ôl Anfon">
+<!ENTITY contextOutgoing.accesskey "n">
+<!ENTITY contextArchive.label "Archifo">
+<!ENTITY contextArchive.accesskey "A">
+
+<!ENTITY contextPeriodic.accesskey "e">
+
+<!ENTITY filterActionDesc.label "Gwneud hyn:">
+<!ENTITY filterActionDesc.accesskey "G">
+
+<!ENTITY filterActionOrderWarning.label "Sylw: Bydd gweithredoedd hidlo'n cael eu rhedeg mewn trefn gwahanol.">
+<!ENTITY filterActionOrder.label "Gw. trefn weithredu">
+
+<!-- New Style Filter Rule Actions -->
+<!ENTITY moveMessage.label "Symud Neges i">
+<!ENTITY copyMessage.label "Copïo Neges i">
+<!ENTITY forwardTo.label "Anfon Neges Ymlaen i">
+<!ENTITY replyWithTemplate.label "Ateb gyda Thempled">
+<!ENTITY markMessageRead.label "Marcio wedi Darllen">
+<!ENTITY markMessageUnread.label "Marcio Heb ei Ddarllen">
+<!ENTITY markMessageStarred.label "Ychwanegu Seren">
+<!ENTITY setPriority.label "Gosod Blaenoriaeth i">
+<!ENTITY addTag.label "Tagio Neges">
+<!ENTITY setJunkScore.label "Gosod Statws Sbam i">
+<!ENTITY deleteMessage.label "Dileu Neges">
+<!ENTITY deleteFromPOP.label "Dileu o'r Gweinydd POP">
+<!ENTITY fetchFromPOP.label "Estyn o'r Gweinydd POP">
+<!ENTITY ignoreThread.label "Anwybyddu'r Edefyn">
+<!ENTITY ignoreSubthread.label "Anwybyddu'r Is-edefyn">
+<!ENTITY watchThread.label "Gwylio'r Edefyn">
+<!ENTITY stopExecution.label "Atal Gweithredu'r Hidl">
+
+<!ENTITY addAction.tooltip "Ychwanegu gweithred newydd">
+<!ENTITY removeAction.tooltip "Tynnu'r weithred hon">
+
+<!-- LOCALIZATION NOTE
+     The values below are used to control the widths of the filter action widgets.
+     Change the values only when the localized strings in the popup menus
+     are truncated in the widgets.
+  -->
+<!-- Flex Attribute: https://developer.mozilla.org/docs/XUL/Attribute/flex -->
+<!ENTITY filterActionTypeFlexValue "1">
+<!ENTITY filterActionTargetFlexValue "4">
diff --git a/l10n-cy/mail/chrome/messenger/FilterListDialog.dtd b/l10n-cy/mail/chrome/messenger/FilterListDialog.dtd
new file mode 100644
index 0000000000..781665cd40
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/FilterListDialog.dtd
@@ -0,0 +1,41 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title "Hidlau Negeseuon">
+<!ENTITY nameColumn.label "Enw Hidl">
+<!ENTITY activeColumn.label "Galluogwyd">
+<!ENTITY newButton.label "Newydd…">
+<!ENTITY newButton.accesskey "N">
+<!ENTITY newButton.popupCopy.label "Copïo…">
+<!ENTITY newButton.popupCopy.accesskey "C">
+<!ENTITY editButton.label "Golygu…">
+<!ENTITY editButton.accesskey "G">
+<!ENTITY deleteButton.label "Dileu">
+<!ENTITY deleteButton.accesskey "D">
+<!ENTITY reorderTopButton "Symud i'r Brig">
+<!ENTITY reorderTopButton.accessKey "B">
+<!ENTITY reorderTopButton.toolTip "Ad-drefnu'r hidl fel ei fod yn gweithredu cyn pob un arall">
+<!ENTITY reorderUpButton.label "Symud i Fyny">
+<!ENTITY reorderUpButton.accesskey "F">
+<!ENTITY reorderDownButton.label "Symud i Lawr">
+<!ENTITY reorderDownButton.accesskey "L">
+<!ENTITY reorderBottomButton "Symud i'r Gwaelod">
+<!ENTITY reorderBottomButton.accessKey "w">
+<!ENTITY reorderBottomButton.toolTip "Ad-drefnu'r hidl fel ei fod yn gweithredu ar ôl pob un arall">
+<!ENTITY filterHeader.label "Bydd hidlau sydd wedi'u galluogi yn rhedeg yn awtomatig yn ôl y drefn â nodir isod.">
+<!ENTITY filtersForPrefix.label "Hidlau ar gyfer:">
+<!ENTITY filtersForPrefix.accesskey "H">
+<!ENTITY viewLogButton.label "Cofnod Hidl">
+<!ENTITY viewLogButton.accesskey "C">
+<!ENTITY runFilters.label "Rhedeg Nawr">
+<!ENTITY runFilters.accesskey "R">
+<!ENTITY stopFilters.label "Atal">
+<!ENTITY stopFilters.accesskey "A">
+<!ENTITY folderPickerPrefix.label "Rhedeg yr hidl(au) ar:">
+<!ENTITY folderPickerPrefix.accesskey "R">
+<!ENTITY helpButton.label "Cymorth">
+<!ENTITY helpButton.accesskey "y">
+<!ENTITY closeCmd.key "W"> 
+<!ENTITY searchBox.emptyText "Chwilio yn ôl enw…">
+
diff --git a/l10n-cy/mail/chrome/messenger/SearchDialog.dtd b/l10n-cy/mail/chrome/messenger/SearchDialog.dtd
new file mode 100644
index 0000000000..c575b26463
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/SearchDialog.dtd
@@ -0,0 +1,41 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- for SearchDialog.xul -->
+
+<!ENTITY searchHeading.label         "Chwilio am negeseuon yn:">
+<!ENTITY searchHeading.accesskey     "h">
+<!ENTITY searchSubfolders.label      "Chwilio is-ffolderi">
+<!ENTITY searchSubfolders.accesskey  "w">
+<!ENTITY searchOnServer.label        "Rhedeg chwilio ar weinydd">
+<!ENTITY searchOnServer.accesskey    "R">
+<!ENTITY resetButton.label           "Clirio">
+<!ENTITY resetButton.accesskey       "C">
+<!ENTITY openButton.label            "Agor">
+<!ENTITY openButton.accesskey        "A">
+<!ENTITY deleteButton.label          "Dileu">
+<!ENTITY deleteButton.accesskey      "D">
+<!ENTITY searchDialogTitle.label     "Chwilio drwy'r Negeseuon">
+<!ENTITY results.label               "Canlyniadau">
+<!ENTITY moveButton.label            "Symud I">
+<!ENTITY moveButton.accesskey        "I">
+<!ENTITY closeCmd.key                "W"> 
+<!ENTITY openInFolder.label          "Agor yn Ffolder">
+<!ENTITY openInFolder.accesskey      "A">
+<!ENTITY saveAsVFButton.label        "Cadw fel Ffolder Chwilio">
+<!ENTITY saveAsVFButton.accesskey    "a">
+<!-- for ABSearchDialog.xul -->
+
+<!ENTITY abSearchHeading.label       "Chwilio yn:">
+<!ENTITY abSearchHeading.accesskey   "h">
+<!ENTITY propertiesButton.label      "Priodweddau">
+<!ENTITY propertiesButton.accesskey  "P">
+<!ENTITY composeButton.label         "Ysgrifennu">
+<!ENTITY composeButton.accesskey     "Y">
+<!ENTITY deleteCardButton.label      "Dileu">
+<!ENTITY deleteCardButton.accesskey  "D">
+<!ENTITY abSearchDialogTitle.label   "Chwilio Uwch drwy'r Llyfr Cyfeiriadau">
+<!-- Thread Pane -->
+
+<!-- Thread Pane Tooltips -->
+
diff --git a/l10n-cy/mail/chrome/messenger/aboutDialog.dtd b/l10n-cy/mail/chrome/messenger/aboutDialog.dtd
new file mode 100644
index 0000000000..62db4469b3
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/aboutDialog.dtd
@@ -0,0 +1,113 @@
+<!ENTITY aboutDialog.title          "Ynghylch &brandFullName;">
+
+<!-- LOCALIZATION NOTE (update.*):
+# These strings are also used in the update pane of preferences.
+# See about:preferences#advanced.
+-->
+<!-- LOCALIZATION NOTE (update.checkForUpdatesButton.*, update.updateButton.*):
+# Only one button is present at a time.
+# The button when displayed is located directly under the Thunderbird version in
+# the about dialog.
+-->
+<!ENTITY update.checkForUpdatesButton.label       "Gwirio am Ddiweddariadau">
+<!ENTITY update.checkForUpdatesButton.accesskey   "D">
+<!ENTITY update.updateButton.label3               "Ailgychwyn i ddiweddaru &brandShorterName;">
+<!ENTITY update.updateButton.accesskey            "A">
+
+
+<!-- LOCALIZATION NOTE (warningDesc.version): This is a warning about the experimental nature of Nightly builds. It is only shown in this version. -->
+<!ENTITY warningDesc.version        "Mae &brandShortName; yn arbrofol a gall fod yn ansad.">
+<!-- LOCALIZATION NOTE (warningDesc.telemetryDesc): This is a notification that Nightly builds automatically send Telemetry data back to Mozilla. It is only shown in this version. "It" refers to brandShortName. -->
+<!ENTITY warningDesc.telemetryDesc  "Mae'n anfon gwybodaeth yn awtomatig am berfformiad, caledwedd, defnydd a chyfaddasu nôl i &vendorShortName; i helpu i wneud &brandShortName; yn well.">
+
+<!-- LOCALIZATION NOTE (community.exp.*) This paragraph is shown in "experimental" builds, i.e. Nightly builds, instead of the other "community.*" strings below. -->
+<!ENTITY community.exp.start        "">
+<!-- LOCALIZATION NOTE (community.exp.mozillaLink): This is a link title that links to https://www.mozilla.org/. -->
+<!ENTITY community.exp.mozillaLink  "Mae &vendorShortName;">
+<!ENTITY community.exp.middle       " yn ">
+<!-- LOCALIZATION NOTE (community.exp.creditslink): This is a link title that links to about:credits. -->
+<!ENTITY community.exp.creditsLink  "gymuned fyd-eang">
+<!ENTITY community.exp.end          " sy'n cydweithio i gadw'r We yn agored, cyhoeddus ac ar gael i bawb.">
+
+<!ENTITY community.start2           "Cynlluniwyd &brandShortName; gan ">
+<!-- LOCALIZATION NOTE (community.mozillaLink): This is a link title that links to https://www.mozilla.org/. -->
+<!ENTITY community.mozillaLink      "&vendorShortName;">
+<!ENTITY community.middle2          ", a ">
+<!-- LOCALIZATION NOTE (community.creditsLink): This is a link title that links to about:credits. -->
+<!ENTITY community.creditsLink      "cymuned fyd-eang">
+<!ENTITY community.end3             " sy'n cydweithio i gadw'r We yn agored, cyhoeddus ac ar gael i bawb.">
+
+<!ENTITY helpus.start               "Hoffech chi helpu? ">
+<!-- LOCALIZATION NOTE (helpus.donateLink): This is a link title that links to the thunderbird donation page -->
+<!ENTITY helpus.donateLink          "Gwnewch gyfraniad">
+<!ENTITY helpus.middle              " neu ">
+<!-- LOCALIZATION NOTE (helpus.getInvolvedLink): This is a link title that links to https://www.thunderbird.net/get-involved/. -->
+<!ENTITY helpus.getInvolvedLink     "beth am ymuno â ni!">
+<!ENTITY helpus.end                 "">
+
+<!ENTITY releaseNotes.link          "Nodiadau ryddhau">
+
+<!-- LOCALIZATION NOTE (bottomLinks.license): This is a link title that links to about:license. -->
+<!ENTITY bottomLinks.license        "Manylion Trwyddedu">
+
+<!-- LOCALIZATION NOTE (bottomLinks.rights): This is a link title that links to about:rights. -->
+<!ENTITY bottomLinks.rights         "Hawliau'r Defnyddiwr">
+
+<!-- LOCALIZATION NOTE (bottomLinks.privacy): This is a link title that links to https://www.mozilla.org/legal/privacy/. -->
+<!ENTITY bottomLinks.privacy        "Polisi Preifatrwydd">
+
+<!-- LOCALIZATION NOTE (update.checkingForUpdates): try to make the localized text short (see bug 596813 for screenshots). -->
+<!ENTITY update.checkingForUpdates  "Gwirio am ddiweddariadau…">
+<!-- LOCALIZATION NOTE (update.noUpdatesFound): try to make the localized text short (see bug 596813 for screenshots). -->
+<!ENTITY update.noUpdatesFound      "Mae &brandShortName; yn gyfredol">
+<!-- LOCALIZATION NOTE (update.adminDisabled): try to make the localized text short (see bug 596813 for screenshots). -->
+<!ENTITY update.adminDisabled       "Mae'r diweddariad wedi'i analluogi gan eich gweinyddwr">
+<!-- LOCALIZATION NOTE (update.otherInstanceHandlingUpdates): try to make the localized text short -->
+<!ENTITY update.otherInstanceHandlingUpdates "Mae &brandShortName; yn cael ei ddiweddaru gan enghraifft arall">
+
+<!-- LOCALIZATION NOTE (update.failed.start,update.failed.linkText,update.failed.end):
+     update.failed.start, update.failed.linkText, and update.failed.end all go into
+     one line with linkText being wrapped in an anchor that links to a site to download
+     the latest version of Firefox (e.g. https://www.firefox.com). As this is all in
+     one line, try to make the localized text short (see bug 596813 for screenshots). -->
+<!ENTITY update.failed.start        "Methodd y diweddaru. ">
+<!ENTITY update.failed.linkText     "Llwytho'r fersiwn diweddaraf i lawr">
+<!ENTITY update.failed.end          "">
+
+<!-- LOCALIZATION NOTE (update.manual.start,update.manual.end): update.manual.start and update.manual.end
+     all go into one line and have an anchor in between with text that is the same as the link to a site
+     to download the latest version of Firefox (e.g. https://www.firefox.com). As this is all in one line,
+     try to make the localized text short (see bug 596813 for screenshots). -->
+<!ENTITY update.manual.start        "Llwytho i lawr ">
+<!ENTITY update.manual.linkText     "y fersiwn diweddaraf">
+<!ENTITY update.manual.end          "">
+
+<!-- LOCALIZATION NOTE (update.unsupported.start,update.unsupported.linkText,update.unsupported.end):
+     update.unsupported.start, update.unsupported.linkText, and
+     update.unsupported.end all go into one line with linkText being wrapped in
+     an anchor that links to a site to provide additional information regarding
+     why the system is no longer supported. As this is all in one line, try to
+     make the localized text short (see bug 843497 for screenshots). -->
+<!ENTITY update.unsupported.start    "Nid oes modd i chi ddiweddaru'r system hwn ymhellach. ">
+<!ENTITY update.unsupported.linkText "Dysgu rhagor">
+<!ENTITY update.unsupported.end      "">
+
+<!-- LOCALIZATION NOTE (update.downloading.start,update.downloading.end): update.downloading.start and
+     update.downloading.end all go into one line, with the amount downloaded inserted in between. As this
+     is all in one line, try to make the localized text short (see bug 596813 for screenshots). The — is
+     the "em dash" (long dash).
+     example: Downloading update — 111 KB of 13 MB -->
+<!ENTITY update.downloading.start   "Llwytho'r diweddariad i lawr - ">
+<!ENTITY update.downloading.end     "">
+
+<!ENTITY update.applying            "Gosod diweddariad…">
+
+<!ENTITY update.restarting          "Ailgychwyn…">
+
+<!-- LOCALIZATION NOTE (channel.description.start,channel.description.end): channel.description.start and
+     channel.description.end create one sentence, with the current channel label inserted in between.
+     example: You are currently on the _Stable_ update channel. -->
+<!ENTITY channel.description.start  "Rydych ar sianel diweddaru ">
+<!ENTITY channel.description.end    ".">
+
+<!ENTITY cmdCloseMac.commandKey "w">
diff --git a/l10n-cy/mail/chrome/messenger/aboutDownloads.dtd b/l10n-cy/mail/chrome/messenger/aboutDownloads.dtd
new file mode 100644
index 0000000000..78ae1b5872
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/aboutDownloads.dtd
@@ -0,0 +1,24 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY aboutDownloads.title                      "Ffeiliau wedi'u Cadw">
+<!ENTITY aboutDownloads.empty                      "Dim Ffeiliau wedi'u Cadw">
+<!-- LOCALIZATION NOTE (cmd.show.label, cmd.show.accesskey, cmd.showMac.label,
+     cmd.showMac.accesskey):
+     The show and showMac commands are never shown together, thus they can share
+     the same access key (though the two access keys can also be different).
+     -->
+<!ENTITY cmd.show.label                            "Agor y Ffolder sy'n eu Cynnwys">
+<!ENTITY cmd.show.accesskey                        "F">
+<!ENTITY cmd.showMac.label                         "Dangos yn Finder">
+<!ENTITY cmd.showMac.accesskey                     "F">
+<!ENTITY cmd.open.label                            "Agor">
+<!ENTITY cmd.open.accesskey                        "o">
+<!ENTITY cmd.removeFromHistory.label               "Tynnu o'r Hanes">
+<!ENTITY cmd.removeFromHistory.accesskey           "T">
+<!ENTITY cmd.clearList.label                       "Clirio'r Rhestr">
+<!ENTITY cmd.clearList.accesskey                   "l">
+<!ENTITY cmd.clearList.tooltip                     "Tynnu pob cofnod o'r rhestr ffeiliau wedi eu cadw, ar wahân i lwythi i lawr sy'n digwydd ar hyn o bryd.">
+<!ENTITY cmd.searchDownloads.label                 "Chwilio…">
+<!ENTITY cmd.searchDownloads.key                   "w">
diff --git a/l10n-cy/mail/chrome/messenger/aboutRights.properties b/l10n-cy/mail/chrome/messenger/aboutRights.properties
new file mode 100644
index 0000000000..2a9f1b93dd
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/aboutRights.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+buttonLabel=Gwybod eich hawliau…
+buttonAccessKey=G
diff --git a/l10n-cy/mail/chrome/messenger/aboutSupportMail.properties b/l10n-cy/mail/chrome/messenger/aboutSupportMail.properties
new file mode 100644
index 0000000000..ad47fddc4c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/aboutSupportMail.properties
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (warningLabel): Label for warning text that shows up when private data is included
+warningLabel=RHYBUDD:
+# LOCALIZATION NOTE (warningText): Warning text that shows up when private data is included
+warningText=Mae hwn yn cynnwys gwybodaeth sensitif na ddylai gael ei anfon ymlaen na'i gyhoeddi heb ganiatâd.
+
+# LOCALIZATION NOTE (fsType.local): Indicator that the displayed directory is on a local drive
+fsType.local = (Gyrrwr lleol)
+# LOCALIZATION NOTE (fsType.network): Indicator that the displayed directory is on the network
+fsType.network = (Gyrrwr rhwydwaith)
+# LOCALIZATION NOTE (fsType.unknown): Indicator that we couldn't figure out whether the directory is local or on a network
+fsType.unknown = (Lleoliad anhysbys)
diff --git a/l10n-cy/mail/chrome/messenger/accountCreation.dtd b/l10n-cy/mail/chrome/messenger/accountCreation.dtd
new file mode 100644
index 0000000000..74537186de
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/accountCreation.dtd
@@ -0,0 +1,112 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY emailWizard.title               "Gosod eich Cyfrif E-bost Cyfredol">
+<!ENTITY emailWizard.caption             "Defnyddiwch eich cyfeiriad e-bost cyfredol">
+<!ENTITY name.label                      "Eich enw:">
+<!ENTITY name.accesskey                  "E">
+<!ENTITY fullname.placeholder            "Eich enw llawn">
+<!ENTITY name.text                       "Eich enw fel mae'n cael ei ddangos i eraill">
+<!ENTITY name.error                      "Rhowch eich enw">
+<!ENTITY email.label                     "Cyfeiriad e-bost:">
+<!ENTITY email.accesskey                 "y">
+<!ENTITY email3.placeholder              "Eich cyfeiriad e-bost">
+<!ENTITY email.text                      "Eich cyfeiriad e-bost cyfredol">
+<!ENTITY email.error                     "Cyfeiriad e-bost annilys">
+<!ENTITY password.label                  "Cyfrinair:">
+<!ENTITY password.accesskey              "C">
+<!ENTITY password.placeholder            "Cyfrinair">
+<!ENTITY password.text                   "Dewisol, fydd ond yn cael ei ddefnyddio i ddilysu'r enw defnyddiwr">
+<!ENTITY password.toggle                 "Dangos/Cuddio cyfrinair">
+<!ENTITY rememberPassword.label          "Cofio'r cyfrinair">
+<!ENTITY rememberPassword.accesskey      "o">
+<!ENTITY usernameEx.label                "Eich mewngofnod:">
+<!ENTITY usernameEx.accesskey            "m">
+<!-- LOCALIZATION NOTE(usernameEx.placeholder): YOURDOMAIN refers to the Windows domain in ActiveDirectory. yourusername refers to the user's account name in Windows. -->
+<!ENTITY usernameEx.placeholder          "YOURDOMAIN\yourusername">
+<!-- LOCALIZATION NOTE(usernameEx.text): Domain refers to the Windows domain in ActiveDirectory. We mean the user's login in Windows at the local corporate network. -->
+<!ENTITY usernameEx.text                 "Mewngofnod parth">
+
+<!ENTITY protocol.label                  "Protocol:">
+<!ENTITY imapLong.label                  "IMAP (ffolder pell)">
+<!ENTITY pop3Long.label                  "POP3 (cadw e-bost ar eich cyfrifiadur)">
+
+<!ENTITY manualConfigTable.summary       "Gosodiadau gweinydd">
+<!ENTITY incoming.label                  "Derbyn:">
+<!ENTITY incomingColumn.label            "Derbyn">
+<!ENTITY outgoing.label                  "Anfon:">
+<!ENTITY outgoingColumn.label            "Anfon">
+<!ENTITY username.label                  "Enw Defnyddiwr:">
+<!ENTITY serverRow.label                 "Gweinydd:">
+<!ENTITY portRow.label                   "Porth:">
+<!ENTITY sslRow.label                    "SSL:">
+<!ENTITY auth.label                      "Dilysu">
+<!ENTITY imap.label                      "IMAP">
+<!ENTITY pop3.label                      "POP3">
+<!-- LOCALIZATION NOTE(exchange.label): Do not translate Exchange, it is a product name. -->
+<!ENTITY exchange.label                  "Exchange">
+<!ENTITY smtp.label                      "SMTP">
+<!ENTITY autodetect.label                "Awtoganfod">
+<!-- LOCALIZATION NOTE(noEncryption.label): Neither SSL/TLS nor STARTTLS.
+     Transmission of emails in cleartext over the Internet. -->
+<!ENTITY noEncryption.label              "Dim">
+<!ENTITY starttls.label                  "STARTTLS">
+<!ENTITY sslTls.label                    "SSL/TLS">
+
+<!-- LOCALIZATION NOTE(exchange-hostname.label): Do not translate Exchange, it is a product name. -->
+<!ENTITY exchange-hostname.label         "Gweinydd Exchange:">
+
+<!ENTITY advancedSetup.label             "Ffurfweddiad uwch">
+<!ENTITY advancedSetup.accesskey         "F">
+<!ENTITY cancel.label                    "Diddymu">
+<!ENTITY cancel.accesskey                "D">
+<!ENTITY continue.label                  "Parhau">
+<!ENTITY continue.accesskey              "P">
+<!ENTITY stop.label                      "Atal">
+<!ENTITY stop.accesskey                  "A">
+<!-- LOCALIZATION NOTE (half-manual-test.label): This is the text that is
+     displayed on the button in manual config mode which will re-guess
+     the account configuration, taking into account the settings that
+     the user has manually changed. -->
+<!ENTITY half-manual-test.label          "Ail brofi">
+<!ENTITY half-manual-test.accesskey      "A">
+<!ENTITY manual-config.label             "Ffurfweddu â llaw…">
+<!ENTITY manual-config.accesskey         "F">
+<!ENTITY open-provisioner.label          "Cael cyfeiriad e-bost newydd…">
+<!ENTITY open-provisioner.accesskey      "c">
+
+
+<!ENTITY get-help.label                  "Derbyn Cymorth">
+<!ENTITY get-help.accesskey              "C">
+
+
+<!ENTITY warning.label                   "Rhybudd!">
+<!ENTITY incomingSettings.label          "Gosodiadau derbyn:">
+<!ENTITY outgoingSettings.label          "Gosodiadau anfon:">
+<!ENTITY technicaldetails.label          "Manylion Technegol">
+<!-- LOCALIZATION NOTE (confirmWarning.label): If there is a security
+     warning on the outgoing server, then the user will need to check a
+     checkbox beside this text before continuing. -->
+<!ENTITY confirmWarning.label            "Rwy'n deall y peryglon.">
+<!ENTITY confirmWarning.accesskey        "p">
+<!-- LOCALIZATION NOTE (doneAccount.label): If there is a security warning
+     on the incoming or outgoing servers, then the page that pops up will
+     have this text in a button to continue by creating the account. -->
+<!ENTITY doneAccount.label               "Gorffen">
+<!ENTITY doneAccount.accesskey           "G">
+<!-- LOCALIZATION NOTE (changeSettings.label): If there is a security warning on
+     the incoming or outgoing servers, then the page that pops up will have
+     this text in a button to take you back to the previous page to change
+     the settings and try again. -->
+<!ENTITY changeSettings.label            "Newid Gosodiadau">
+<!ENTITY changeSettings.accesskey        "G">
+
+<!ENTITY contactYourProvider.description "Mae &brandShortName; yn gallu caniatáu i chi estyn eich e-bost drwy ddefnyddio'r ffurfweddiad parod. Er hynny, dylech gysylltu â'ch gweinyddwr neu ddarparwr e-bost ynghylch cysylltiadau anaddas. Gw. Cwestiynau Thunderbird am ragor o wybodaeth.">
+
+<!ENTITY insecureServer.tooltip.title    "Rhybudd! Mae hwn yn weinydd anniogel.">
+<!ENTITY insecureServer.tooltip.details  "Cliciwch y cylch am ragor o wybodaeth.">
+
+<!ENTITY insecureUnencrypted.description "Mae eich e-bost a'ch dilysu yn cael eu hanfon heb eu hamgryptio, felly mae modd i eraill ddarllen eich cyfrinair (a'ch neges) yn hawdd. Bydd &brandShortName; yn caniatáu i chi estyn eich e-bost ond dylech gysylltu â'ch darparwr ynghylch ffurfweddu'r gweinydd gyda chysylltiad diogel.">
+<!ENTITY insecureSelfSigned.description  "Mae'r gweinydd yn defnyddio tystysgrif nad ydym yn gallu ymddiried ynddi, felly nid ydym yn gallu bod yn siŵr nad oes rhywun yn cipio'r traffig rhwng &brandShortName; a'ch gweinydd. Bydd &brandShortName; yn caniatáu i chi estyn eich e-bost ond dylech sicrhau fod y darparwr e-bost yn ffurfweddu'r gweinydd gyda tystysgrif mae modd ymddiried ynddi.">
+<!ENTITY secureServer.description        "Llongyfarchiadau! Mae hwn yn weinydd diogel.">
diff --git a/l10n-cy/mail/chrome/messenger/accountCreation.properties b/l10n-cy/mail/chrome/messenger/accountCreation.properties
new file mode 100644
index 0000000000..8032a49366
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/accountCreation.properties
@@ -0,0 +1,114 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# accountCreation.properties
+
+# LOCALIZATION NOTE(cleartext_warning): %1$S will be the hostname of the server the user was trying to connect to.
+cleartext_warning=Nid yw %1$S yn defnyddio amgryptiad.
+# LOCALIZATION NOTE(selfsigned_warning): %1$S will be the hostname of the server the user was trying to connect to.
+selfsigned_warning=Nid yw %1$S yn defnyddio tystysgrif y gellir ymddiried ynddi.
+selfsigned_details=Fel rheol, bydd gweinydd e-bost diogel yn derbyn tystysgrif mae modd ymddiried ynddi er mwyn profi ei fod y gweinydd mae'n honni ei fod. Bydd y cysylltiad gyda'r gweinydd wedi'i amgryptio ond nid oes modd ei ddilysu fel y gweinydd cywir.
+cleartext_details=Nid yw gweinyddion e-bost anniogel yn defnyddio cysylltiadau wedi'u hamgryptio i amddiffyn eich cyfrinair a gwybodaeth breifat. Drwy gysylltu â'r gweinydd yma mae modd i chi amlygu eich cyfrinair a gwybodaeth bersonol.
+
+# LOCALIZATION NOTE(default_server_tag): Used to indicate the default smtp server in the server dropdown list.
+default_server_tag= (rhagosodiad)
+# LOCALIZATION NOTE(port_auto): It must be short (4-5 characters max.).
+# Content of server port field (usually a number), used when the user didn't
+# enter anything yet and we'll automatically detect it later.
+port_auto=Awto
+
+# config titles
+looking_up_settings=Chwilio am y ffurfweddiad…
+# LOCALIZATION NOTE(looking_up_settings_disk): Referring to Thunderbird installation folder on user's harddisk. %1$S will be the brandShortName.
+looking_up_settings_disk=Chwilio'r ffurfweddiad: gosod %1$S
+looking_up_settings_isp=Chwilio am ffurfweddiad: Darparwr e-bost
+# LOCALIZATION NOTE(looking_up_settings_db): Do not translate or replace Mozilla. It stands for the public project mozilla.org, not Mozilla Corporation. The database is a generic, public domain facility usable by any client.
+looking_up_settings_db=Chwilio'r ffurfweddiad: cronfa ddata ISP Mozilla
+looking_up_settings_mx=Chwilio am ffurfweddiad: parth e-bost derbyn
+# LOCALIZATION NOTE(looking_up_settings_exchange): Exchange is a product name
+looking_up_settings_exchange=Chwilio am ffurfweddiad: Gweinydd Exchange
+# LOCALIZATION NOTE(looking_up_settings_guess): We are checking common server names like pop., pop3., smtp., mail., without knowing whether they exist or really serve this email account. If a server responds, we try to talk to it via POP/IMAP/SMTP protocols and query its capabilities. If that succeeds, we assume we found a configuration. Of course, it may still be wrong, but it often works.
+looking_up_settings_guess=Chwilio'r ffurfweddiad: Defnyddio enwau gweinyddion cyffredin
+looking_up_settings_halfmanual=Chwilio am ffurfweddiad: Cyfathrebu â'r gweinydd
+# LOCALIZATION NOTE(found_settings_disk): Referring to Thunderbird installation folder on user's harddisk. %1$S will be the brandShortName.
+found_settings_disk=Ffurfweddiad wedi'i ganfod ar osodiad %1$S
+found_settings_isp=Ffurfweddiad wedi'i ganfod gan y darparwr e-bost
+# LOCALIZATION NOTE(found_settings_db): Do not translate or replace Mozilla. It stands for the public project mozilla.org, not Mozilla Corporation. The database is a generic, public domain facility usable by any client.
+found_settings_db=Ffurfweddiad wedi'i ganfod ar gronfa ddata ISP Mozilla
+# LOCALIZATION NOTE(found_settings_exchange): Microsoft Exchange is a product name.
+found_settings_exchange=Ffurfweddiad ar gyfer Microsoft Exchange wedi ei ganfod
+no-open-protocols=Yn anffodus nid yw'r gweinydd e-bost hwn yn cynnnal protocolau agored.
+addon-intro=Gall ychwaneguyn trydydd parti ganiatau i chi gael mynediad i'ch cyfrif e-bost ar y gweinydd hwn:
+# LOCALIZATION NOTE(found_settings_guess): We tried common mail server names and we found a mail server and talked to it and it responded properly, so we think we found a suitable configuration, but we are only about 80% certain that it is the correct setting for this email address. There's a chance that email address may not actually be served by this server and it won't work, or that there is a better server.
+found_settings_guess=Ffurfweddiad wedi'i ganfod drwy enwau gweinyddion cyffredin
+found_settings_halfmanual=Mae'r gosodiadau canlynol wedi'u canfod wrth gyfathrebu â'r gweinydd
+# LOCALIZATION NOTE(failed_to_find_settings): %1$S will be the brandShortName.
+failed_to_find_settings=Mae %1$S wedi methu â chanfod gosodiadau eich cyfrif e-bost.
+manually_edit_config=Golygu'r Ffurfweddiad
+# LOCALIZATION NOTE(guessed_settings_offline) User is offline, so we just took a wild guess and the user will have to enter the right settings.
+guessed_settings_offline=Rydych all-lein. Rydym wedi dyfalu rhai gosodiadau ond bydd angen i chi osod y gosodiadau cywir.
+
+# config subtitles
+check_preconfig=gwirio am rhagosodiad…
+found_preconfig=wedi canfod y rhag ffurfweddiad
+checking_config=gwirio'r ffurfweddiad…
+found_config=Wedi canfod ffurfweddiad eich cyfrif
+checking_mozilla_config=gwirio ffurfweddiadau Mozilla Community…
+found_isp_config=wedi canfod ffurfweddiad
+probing_config=cyfathrebu â ffurfweddiad…
+guessing_from_email=dyfalu ffurfweddiad…
+config_details_found=Mae manylion eich ffurfweddiad wedi'u canfod!
+config_unverifiable=Nid oedd modd dilysu'r ffurfweddiad - a yw'r enw defnyddiwr neu gyfrinair yn anghywir?
+exchange_config_unverifiable=Nid oes modd gwirio'r ffurfweddiad. Os yw'ch enw defnyddiwr a'ch cyfrinair yn gywir, mae'n debygol bod gweinyddwr y gweinydd wedi analluogi'r ffurfweddiad a ddewiswyd ar gyfer eich cyfrif. Ceisiwch ddewis protocol arall.
+incoming_found_specify_outgoing=Mae manylion ffurfweddiad eich gweinydd derbyn wedi'u canfod, pennwch enw'r gwesteiwr sy'n anfon.
+outgoing_found_specify_incoming=Mae manylion ffurfweddiad eich gweinydd anfon wedi'u canfod, pennwch enw'r gwesteiwr sy'n derbyn.
+please_enter_missing_hostnames=Methu dyfalu'r gosodiadau - rhowch yr enwau gwesteiwyr coll.
+incoming_failed_trying_outgoing=Methu ffurfweddu'r gweinydd derbyn yn awtomatig, dal i geisio ar gyfer y gweinydd anfon.
+outgoing_failed_trying_incoming=Methu ffurfweddu'r gweinydd anfon yn awtomatig, dal ei geisio ar gyfer y gweinydd derbyn.
+checking_password=Gwirio'r cyfrinair…
+password_ok=Cyfrinair yn iawn!
+user_pass_invalid=Enw defnyddiwr neu gyfrinair annilys
+check_server_details=Gwirio manylion y gweinydd
+check_in_server_details=Gwirio manylion y gweinydd derbyn
+check_out_server_details=Gwirio manylion gweinydd anfon
+
+error_creating_account=Gwall wrth Greu Cyfrif
+incoming_server_exists=Mae'r gweinydd derbyn yn bodoli eisoes.
+
+please_enter_name=Rhowch eich enw.
+double_check_email=Gwiriwch y cyfeiriad e-bost eto!
+
+# add-on install
+addonInstallStarted=Llwytho i lawr a gosod ychwanegyn…
+addonInstallSuccess=Wedi gosod yr ychwanegynn yn llwyddiannus.
+# LOCALIZATION NOTE(addonInstallLabel): %1$S will be the add-on name
+addonInstallShortLabel=Gosod
+
+#config result display
+# LOCALIZATION NOTE(resultUnknown): Displayed instead of resultIncoming,
+# resultOutgoing or resultUsername when we don't have a proper value.
+resultUnknown=Anhysbys
+resultOutgoingExisting=Defnyddio'r gweinydd SMTP anfon cyfredol
+resultIMAP=IMAP
+resultPOP3=POP3
+resultSMTP=SMTP
+resultExchange=Exchange
+# LOCALIZATION NOTE(resultNoEncryption): Neither SSL/TLS nor STARTTLS. Transmission of emails in cleartext over the Internet.
+resultNoEncryption=Dim Amgryptiad
+resultSSL=SSL
+resultSTARTTLS=STARTTLS
+resultSSLCertWeak=\u0020(Rhybudd: Methu dilysu'r gweinydd)
+resultSSLCertOK=
+resultUsernameBoth=%1$S
+resultUsernameDifferent=Derbyn: %1$S, Anfon: %2$S
+
+confirmAdvancedConfigTitle=Cadarnhau Ffurfweddiad Uwch
+confirmAdvancedConfigText=Bydd y ddeialog hon yn cael ei chau a bydd cyfrif gyda'r gosodiadau cyfredol yn cael ei greu, hyd yn oed os yw'r ffurfweddiad yn anghywir. Hoffech chi barhau?
+
+# LOCALIZATION NOTE(credentials_incomplete): The reference to "janedoe" (Jane Doe) is the name of an example person. You will want to translate it to whatever example persons would be named in your language. In the example, AD is the name of the Windows domain, and this should usually not be translated.
+credentials_incomplete=Methodd y dilysu. Naill ai mae'r manylion a gofnodwyd yn anghywir neu mae angen enw defnyddiwr ar wahân ar gyfer mewngofnodi. Yr enw defnyddiwr hwn fel rheol yw eich mewngofnod parth Windows gyda'r parth neu hebddo (er enghraifft, janedoe neu AD\\janedoe).
+credentials_wrong=Methodd y dilysu. Gwiriwch yr enw defnyddiwr a'r cyfrinair.
+# LOCALIZATION NOTE(otherDomain.label): %1$S will be the brandShortName. %2$S refers to the domain name, e.g. rackspace.com
+otherDomain.label=Mae %1$S wedi canfod manylion gosod eich cyfrif ar %2$S. Hoffech chi barhau a chyflwyno'ch manylion?
+otherDomain_ok.label=Mewngofnodi
+otherDomain_cancel.label=Diddymu
diff --git a/l10n-cy/mail/chrome/messenger/accountCreationModel.properties b/l10n-cy/mail/chrome/messenger/accountCreationModel.properties
new file mode 100644
index 0000000000..3ac780124a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/accountCreationModel.properties
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This file has the strings, mostly error strings, for the logic / JS backend / model
+# files: fetchConfig.js, readFromXML.js, guessConfig.js, verifyConfig.js, createInBackend.js
+
+
+# readFromXML.js
+no_emailProvider.error=Nid yw'r ffeil ffurfweddu XML yn cynnwys ffurfweddiad cyfrif e-bost.
+outgoing_not_smtp.error=Rhaid i'r gweinydd anfon fod o fath SMTP
+
+# verifyConfig.js
+cannot_login.error=Methu mewngofnodi i'r gweinydd. Ffurfweddiad, enw defnyddiwr neu gyfrinair anghywir, siŵr o fod.
+
+
+# guessConfig.js
+cannot_find_server.error=Methu canfod gweinydd
+
+# exchangeAutoDiscover.js
+no_autodiscover.error=Mae'r Exchangen AutoDiscover XML yn annilys.
diff --git a/l10n-cy/mail/chrome/messenger/accountCreationUtil.properties b/l10n-cy/mail/chrome/messenger/accountCreationUtil.properties
new file mode 100644
index 0000000000..46728d91bd
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/accountCreationUtil.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This file has the strings, mostly error strings, for the logic / JS backend / model
+# files: sanitizeDatatypes.js, fetchhttp.js, util.js
+
+
+# sanitizeDatatypes.js
+hostname_syntax.error=Mae'r enw gweinydd yn wag neu yn cynnwys nodau anghymeradwy. Dim ond llythrennau, rhifau, - a . sy'n cael eu caniatáu.
+alphanumdash.error=Mae'r llinyn yn cynnwys nodau anghymeradwy. Dim ond llythrennau, rhifau, - a . sy'n cael eu caniatáu.
+allowed_value.error=Nid yw'r gwerth hwn yn gymeradwy
+url_scheme.error=Nid oes caniatâd i'r cynllun URL
+url_parsing.error=Heb adnabod yr URL
+string_empty.error=Rhaid darparu gwerth ar gyfer y llinyn
+boolean.error=Nid booleanaidd
+no_number.error=Nid rhif
+number_too_large.error=Rhif yn rhy fawr
+number_too_small.error=Rhif yn rhy fach
+
+
+# fetchhttp.js
+cannot_contact_server.error=Methu cysylltu â'r gweinydd
+bad_response_content.error=Cynnwys ymateb gwael
+
+# verifyConfig.js
+# LOCALIZATION NOTE(auth_failed_generic.error): The login failed (server refused to allow the user in), but the server did not give any meaningful error message. This is a common case when the user entered a wrong password or is otherwise not allowed.
+auth_failed_generic.error=Methodd y mewngofnodi. A yw'r enw defnyddiwr/cyfeiriad e-bost a chyfrinair yn gywir?
+# LOCALIZATION NOTE(auth_failed_with_reason.error): The login failed (server refused to allow the user in), and the server gave an error message which we can present to the user. This is a common case when the user entered a wrong password or is otherwise not allowed. %1$S will be the IMAP/POP3/SMTP server hostname. %2$S will be the error message from the server (usually in the local language where the server is or in English).
+auth_failed_with_reason.error=Methodd y mewngofnodi. Dywedodd gweinydd %1$S: %2$S
+# LOCALIZATION NOTE(verification_failed.error): We had some other error, not during authentication with the server, but at earlier points, e.g. locally or we entirely failed to contact the given server, and we unfortunately have no detailed error message.
+verification_failed.error=Methiant dilysu mewngofnodi am reswm anhysbys.
+# LOCALIZATION NOTE(verification_failed_with_exception.error): We had some other error, not during authentication with the server, but at earlier points, e.g. locally or we entirely failed to contact the given server, and we have an error message. %1$S will be an error message, possibly in English
+verification_failed_with_exception.error=Methiant dilysu mewngofnodi gyda'r neges: %1$S
diff --git a/l10n-cy/mail/chrome/messenger/activity.dtd b/l10n-cy/mail/chrome/messenger/activity.dtd
new file mode 100644
index 0000000000..8519323959
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/activity.dtd
@@ -0,0 +1,37 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (window.width2, window.height): These values should be
+close to the golden ratio (1.618:1) while making sure it's wide enough for long
+file names and tall enough to hint that there are more activities in the list -->
+
+<!ENTITY window.width2                    "485">
+<!ENTITY window.height                    "300">
+
+<!ENTITY activity.title                  "Rheolwr Gweithgaredd">
+
+<!ENTITY cmd.pause.label                  "Oedi">
+<!ENTITY cmd.pause.accesskey              "O">
+<!ENTITY cmd.resume.label                 "Ailgychwyn">
+<!ENTITY cmd.resume.accesskey             "A">
+<!ENTITY cmd.cancel.label                 "Diddymu">
+<!ENTITY cmd.cancel.accesskey             "D">
+<!ENTITY cmd.undo.label                   "Dadwneud">
+<!ENTITY cmd.undo.accesskey               "w">
+<!ENTITY cmd.recover.label                "Adfer">
+<!ENTITY cmd.recover.accesskey            "f">
+<!ENTITY cmd.retry.label                  "Ceisio Eto">
+<!ENTITY cmd.retry.accesskey              "E">
+<!ENTITY cmd.removeFromList.label         "Tynnu o'r Rhestr">
+<!ENTITY cmd.removeFromList.accesskey     "T">
+
+<!ENTITY cmd.close.commandkey             "w">
+<!ENTITY cmd.close2.commandkey            "j">
+<!ENTITY cmd.close2Unix.commandkey        "y">
+<!ENTITY cmd.clearList.label              "Clirio'r Rhestr">
+<!ENTITY cmd.clearList.tooltip            "Tynnu eitemau wedi'u cwblhau, diddymu a methu o'r rhestr">
+<!ENTITY cmd.clearList.accesskey          "C">
+<!ENTITY cmd.find.commandkey              "f">
+<!ENTITY cmd.search.commandkey            "k">
+
+<!ENTITY searchBox.label                  "Chwilio…">
diff --git a/l10n-cy/mail/chrome/messenger/activity.properties b/l10n-cy/mail/chrome/messenger/activity.properties
new file mode 100644
index 0000000000..7a4cd2eedc
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/activity.properties
@@ -0,0 +1,99 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Status Text
+paused2=Oedwyd
+processing=Prosesu
+notStarted=Heb Gychwyn
+failed=Methwyd
+waitingForInput=Aros am fewnbwn
+waitingForRetry=Aros i geisio eto
+completed=Cwblhawyd
+canceled=Diddymwyd
+
+# LOCALIZATION NOTE (sendingMessages): this is used as a title for grouping processes in the activity manager when sending email.
+sendingMessages=Anfon Negeseuon
+sendingMessage=Anfon Neges
+# LOCALIZATION NOTE (sendingMessageWithSubject): %S will be replaced by the subject of the message being sent.
+sendingMessageWithSubject=Anfon Neges: %S
+copyMessage=Copïo neges i'r ffolder anfonwyd
+sentMessage=Neges Anfonwyd
+# LOCALIZATION NOTE (sentMessageWithSubject): %S will be replaced by the subject of the message being sent.
+sentMessageWithSubject=Neges Anfonwyd: %S
+failedToSendMessage=Methwyd anfon neges
+failedToCopyMessage=Methwyd copïo neges
+# LOCALIZATION NOTE (failedToSendMessageWithSubject): %S will be replaced by the subject of the message being sent.
+failedToSendMessageWithSubject=Methwyd anfon neges: %S
+# LOCALIZATION NOTE (failedToCopyMessageWithSubject): %S will be replaced by the subject of the message being sent.
+failedToCopyMessageWithSubject=Methwyd copïo neges: %S
+
+# LOCALIZATION NOTE (autosyncProcessProgress2): Do not translate the words "%1$S", "%2$S", "%3$S" and "%4$S" below.
+# Place the word %1$S in your translation where the number of the message being downloaded should appear.
+# Place the word %2$S in your translation where the total number of messages to be downloaded should appear.
+# Place the word %3$S in your translation where the name of the folder being processed should appear.
+# Place the word %4$S in your translation where the name of account being processed should appear.
+# EXAMPLE: Ted's account: Downloading message 334 of 1008 in Inbox…
+autosyncProcessProgress2=%4$S: Llwytho %1$S neges i lawr o %2$S i %3$S…
+# LOCALIZATION NOTE (autosyncProcessDisplayText): %S will be replaced by the folder name
+autosyncProcessDisplayText=Diweddaru ffolder %S
+# LOCALIZATION NOTE (autosyncEventDisplayText): %S will be replaced by the account name
+autosyncEventDisplayText=Mae %S yn gyfredol
+# LOCALIZATION NOTE (autosyncEventStatusText): %S will be replaced by total number of downloaded messages
+autosyncEventStatusText=Cyfanswm y nifer o negeseuon wedi'u llwytho i lawr: %S
+autosyncEventStatusTextNoMsgs=Heb lwytho negeseuon i lawr
+# LOCALIZATION NOTE (autosyncContextDisplayText): %S will be replaced by the account name
+autosyncContextDisplayText=Cydweddu: %S
+
+# LOCALIZATION NOTE (pop3EventStartDisplayText2): Do not translate the words "%1$S" and "%2$S" below.
+# Place the word %1$S in your translation where the name of the account being checked for new messages should appear.
+# Place the word %2$S in your translation where the name of the folder being checked for new messages should appear.
+# EXAMPLE: George's account: Checking Inbox for new messages…
+pop3EventStartDisplayText2=%1$S: Gwirio %2$S am negeseuon newydd…
+# LOCALIZATION NOTE (pop3EventDisplayText): %S will be replaced by the account name
+pop3EventDisplayText=Mae %S yn gyfredol
+# LOCALIZATION NOTE (pop3EventStatusText): #1 will be replaced by total number of downloaded messages
+pop3EventStatusText=#1 neges wedi'i lwytho i lawr;#1 neges wedi'u llwytho i lawr;
+pop3EventStatusTextNoMsgs=Dim negeseuon i'w llwytho i lawr
+
+# Message actions that show up in activity manager
+# LOCALIZATION NOTE (deletedMessages2): #1 number of messages, #2 folder name
+deletedMessages2=Dilëwyd #1 neges o #2;Dilëwyd #1 neges o #2
+# LOCALIZATION NOTE (movedMessages): #1 number of messages, #2 and #3: folder names
+movedMessages=Symudwyd #1 neges o #2 i #3;Symudwyd #1 neges o #2 i #3
+# LOCALIZATION NOTE (copiedMessages): #1 number of messages, #2 and #3: folder names
+copiedMessages=Copïwyd #1 neges o #2 i #3;Copïwyd #1 neges o #2 i #3
+# LOCALIZATION NOTE (fromServerToServer): #1 source server, #2 destination server
+fromServerToServer=0 #1 i #2
+# LOCALIZATION NOTE (deletedFolder): #1 folder name
+deletedFolder=Dilëwyd ffolder #1
+emptiedTrash=Sbwriel wedi'i Wagio
+# LOCALIZATION NOTE (movedFolder): #1 and #2 are folder names
+movedFolder=Syymudwyd ffolder #1 i #2
+# LOCALIZATION NOTE (movedFolderToTrash): #1 is the folder name
+movedFolderToTrash=Symudwyd ffolder #1 i'r Sbwriel
+# LOCALIZATION NOTE (copiedFolder): #1 and #2 are folder names
+copiedFolder=Copïwyd ffolder #1 i ffolder #2
+# LOCALIZATION NOTE (renamedFolder): #1 and #2 are folder names
+renamedFolder=Ailenwi ffolder #1 i #2
+indexing=Mynegeio negeseuon
+# LOCALIZATION NOTE (indexingFolder): #1 is a folder name
+indexingFolder=Mynegeio negeseuon yn #1
+indexingStatusVague=Pennu pa negeseuon i'w mynegeio
+# LOCALIZATION NOTE (indexingFolderStatusVague): #1 is a folder name
+indexingFolderStatusVague=Pennu pa negeseuon i'w mynegeio yn #1
+# LOCALIZATION NOTE (indexingStatusExact):
+#   #1 is the number of the message currently being indexed
+#   #2 is the total number of messages being indexed
+#   #3 is the percentage of indexing that is complete
+indexingStatusExact=Mynegeio #1 o #2 neges;Mynegeio #1 o #2 neges (wedi cwblhau #3%)
+# LOCALIZATION NOTE (indexingFolderStatusExact):
+#   #1 is the number of the message currently being indexed
+#   #2 is the total number of messages being indexed
+#   #3 is the percentage of indexing that is complete
+#   #4 is a folder name
+indexingFolderStatusExact=Mynegeio #1 o #2 neges yn #4;Mynegeio #1 o #2 neges yn #4; (wedi cwblhau #3%)
+# LOCALIZATION NOTE (indexedFolder): #1 number of messages; #2 folder name
+indexedFolder=Mynegewyd #1 neges yn #2;Mynegewyd #1 neges yn #2
+# LOCALIZATION NOTE (indexedFolderStatus): #1 number of seconds spent indexing
+indexedFolderStatus=#1 eiliad wedi mynd heibio;#1 eiliad wedi mynd heibio
diff --git a/l10n-cy/mail/chrome/messenger/addbuddy.dtd b/l10n-cy/mail/chrome/messenger/addbuddy.dtd
new file mode 100644
index 0000000000..bafd30d80c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addbuddy.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY addBuddyWindow.title           "Ychwanegu cysylltiad">
+<!ENTITY name.label                     "Enw Defnyddiwr">
+<!ENTITY account.label                  "Cyfrif">
diff --git a/l10n-cy/mail/chrome/messenger/addons.properties b/l10n-cy/mail/chrome/messenger/addons.properties
new file mode 100644
index 0000000000..54be86347f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addons.properties
@@ -0,0 +1,251 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+xpinstallPromptMessage=Rhwystrodd %S y wefan rhag gofyn i chi osod meddalwedd ar eich cyfrifiadur.
+# LOCALIZATION NOTE (xpinstallPromptMessage.header)
+# The string contains the hostname of the site the add-on is being installed from.
+xpinstallPromptMessage.header=Caniatáu i %S osod ategyn?
+xpinstallPromptMessage.message=Rydych yn ceisio gosod ychwanegyn o %S. Gwnewch yn siŵr eich bod yn ymddiried yn y wefan hon cyn parhau.
+xpinstallPromptMessage.header.unknown=Caniatáu i wefan anhysbys osod ategyn?
+xpinstallPromptMessage.message.unknown=Rydych yn ceisio gosod ychwanegyn o wefan anhysbys. Gwnewch yn siŵr eich bod yn ymddiried yn y wefan hon cyn parhau.
+xpinstallPromptMessage.learnMore=Dysgwch ragor am osod ategion yn ddiogel
+xpinstallPromptMessage.dontAllow=Peidio Caniatáu
+xpinstallPromptMessage.dontAllow.accesskey=P
+xpinstallPromptMessage.neverAllow=Byth Caniatáu
+xpinstallPromptMessage.neverAllow.accesskey=B
+# Accessibility Note:
+# Be sure you do not choose an accesskey that is used elsewhere in the active context (e.g. main menu bar, submenu of the warning popup button)
+# See https://website-archive.mozilla.org/www.mozilla.org/access/access/keyboard/ for details
+xpinstallPromptMessage.install=Ymlaen i'r Gosod
+xpinstallPromptMessage.install.accesskey=Y
+
+# Accessibility Note:
+# Be sure you do not choose an accesskey that is used elsewhere in the active context (e.g. main menu bar, submenu of the warning popup button)
+# See http://www.mozilla.org/access/keyboard/accesskey for details
+xpinstallDisabledMessageLocked=Mae gosod meddalwedd wedi ei analluogi gan eich gweinyddwr system.
+xpinstallDisabledMessage=Mae gosod meddalwedd wedi ei analluogi. Cliciwch Galluogi a cheisio eto.
+xpinstallDisabledButton=Galluogi
+xpinstallDisabledButton.accesskey=G
+
+# LOCALIZATION NOTE (addonInstallBlockedByPolicy)
+# This message is shown when the installation of an add-on is blocked by
+# enterprise policy. %1$S is replaced by the name of the add-on.
+# %2$S is replaced by the ID of add-on. %3$S is a custom message that
+# the administration can add to the message.
+addonInstallBlockedByPolicy=Mae %1$S (%2$S) wedi ei rwystro gan eich gweinyddwr system.%3$S
+
+# LOCALIZATION NOTE (addonPostInstall.message1)
+# %1$S is replaced with the localized named of the extension that was
+# just installed.
+# %2$S is replaced with the localized name of the application.
+addonPostInstall.message1=Mae %1$S wedi ei ychwanegu at %2$S.
+# LOCALIZATION NOTE (addonPostInstall.multiple.message1)
+# %1$S is replaced with the localized name of the application.
+addonPostInstall.multiple.message=Cafodd yr ychwanegion hyn eu hychwanegu i %1$S:
+addonPostInstall.okay.label=Iawn
+addonPostInstall.okay.accesskey=I
+
+# LOCALIZATION NOTE (addonDownloadingAndVerifying):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# Also see https://bugzilla.mozilla.org/show_bug.cgi?id=570012 for mockups
+addonDownloadingAndVerifying=Llwytho i lawr a dilysu #1 ychwanegion…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…;Llwytho i lawr a dilysu #1 ychwanegyn…
+addonDownloadVerifying=Dilysu
+
+addonInstall.unsigned=(Heb eu gwirio)
+addonInstall.cancelButton.label=Diddymu
+addonInstall.cancelButton.accesskey=D
+addonInstall.acceptButton2.label=Ychwanegu
+addonInstall.acceptButton2.accesskey=Y
+
+# LOCALIZATION NOTE (addonConfirmInstallMessage,addonConfirmInstallUnsigned):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName
+# #2 is the number of add-ons being installed
+addonConfirmInstall.message=Hoffai'r wefan hon osod ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:;Hoffai'r wefan hon osod #2 ychwanegyn yn #1:
+addonConfirmInstallUnsigned.message=Rhybudd: Hoffai&#39;r wefan hon osod ychwanegiad heb ei wirio yn # 1. Ewch yn eich perygl eich hun.; Rhybudd: Hoffai&#39;r wefan hon osod # 2 ychwanegiadau heb eu cadarnhau yn # 1. Ewch ymlaen ar eich pen eich hun.
+
+# LOCALIZATION NOTE (addonConfirmInstallSomeUnsigned.message):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is brandShortName
+# #2 is the total number of add-ons being installed (at least 2)
+addonConfirmInstallSomeUnsigned.message=;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegion yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.;Rhybudd: Hoffai'r wefan hon osod #2 ychwanegyn yn #1, mae rhai ohonynt heb eu gwirio. Gwnewch hyn ar eich menter eich hun.
+
+# LOCALIZATION NOTE (addonInstalled):
+# %S is the name of the add-on
+addonInstalled=Mae %S wedi'i osod yn llwyddiannus.
+# LOCALIZATION NOTE (addonsGenericInstalled):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of add-ons
+addonsGenericInstalled=Nid oes ychwanegion wedi eu gosod.;Mae #1 ychwanegyn wedi ei osod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.;Mae #1 ychwanegyn wedi eu gosod yn llwyddiannus.
+
+# LOCALIZATION NOTE (addonInstallError-1, addonInstallError-2, addonInstallError-3, addonInstallError-4, addonInstallError-5, addonLocalInstallError-1, addonLocalInstallError-2, addonLocalInstallError-3, addonLocalInstallError-4, addonLocalInstallError-5):
+# %1$S is the application name, %2$S is the add-on name
+addonInstallError-1=Nid oedd modd llwytho'r ychwanegyn i lawr oherwydd methiant y cysylltiad.
+addonInstallError-2=Nid oedd modd gosod yr ychwanegyn am nad yw'n cydweddu â'r ychwanegyn roedd %1$S yn ei ddisgwyl.
+addonInstallError-3=Nid oedd modd llwytho'r ychwanegyn i lawr o'r wefan hon oherwydd ei fod yn ymddangos yn llwgr.
+addonInstallError-4=Nid oedd modd gosod %2$S gan nad oedd %1$S yn gallu newid y linell angenrheidiol.
+addonInstallError-5=Mae %1$S wedi atal y wefan rhag gosod ychwanegyn sydd heb ei wirio.
+addonLocalInstallError-1=Nid oedd modd gosod yr ychwanegyn oherwydd gwall system.
+addonLocalInstallError-2=Nid oedd modd gosod yr ychwanegyn am nad yw'n cydweddu â'r ychwanegyn %1$S disgwyliwyd.
+addonLocalInstallError-3=Nid oedd modd gosod yr ychwanegyn am ei fod yn edrych yn llwgr.
+addonLocalInstallError-4=Nid oedd modd gosod %2$S gan nad oedd %1$S yn gallu newid y linell angenrheidiol.
+addonLocalInstallError-5=Nid oedd modd gosod yr ychwanegyn am nad yw wedi ei wirio.
+
+# LOCALIZATION NOTE (addonInstallErrorIncompatible):
+# %1$S is the application name, %2$S is the application version, %3$S is the add-on name
+addonInstallErrorIncompatible=Nid oedd modd gosod %3$S am nad yw'n cydweddu â %1$S %2$S.
+
+# LOCALIZATION NOTE (addonInstallErrorBlocklisted): %S is add-on name
+addonInstallErrorBlocklisted=Nid oedd modd gosod %S am fod risg uchel iddo achosi problemau sefydlogrwydd a diogelwch.
+
+# LOCALIZATION NOTE (webextPerms.header)
+# This string is used as a header in the webextension permissions dialog,
+# %S is replaced with the localized name of the extension being installed.
+# See https://bug1308309.bmoattachments.org/attachment.cgi?id=8814612
+# for an example of the full dialog.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.header=Ychwanegu %S?
+
+# %S is brandShortName
+webextPerms.experimentWarning=Gall ychwanegion maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Gosodwch yr ychwanegiad hwn dim ond os ydych yn ymddiried yn y ffynhonnell.
+webextPerms.unsignedWarning=Rhybudd: Nid yw'r ychwanegyn hwn wedi ei wirio. Gall ychwanegion maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Gosodwch hwn dim ond os ydych yn ymddiried yn ei ffynhonnell.
+
+# LOCALIZATION NOTE (webextPerms.listIntro)
+# This string will be followed by a list of permissions requested
+# by the webextension.
+webextPerms.listIntro=Mae'n gofyn am eich caniatâd i:
+webextPerms.learnMore=Dysgu rhagor am ganiatâd
+webextPerms.add.label=Ychwanegu
+webextPerms.add.accessKey=Y
+webextPerms.cancel.label=Diddymu
+webextPerms.cancel.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.sideloadMenuItem)
+# %1$S will be replaced with the localized name of the sideloaded add-on.
+# %2$S will be replace with the name of the application (e.g., Firefox, Nightly)
+webextPerms.sideloadMenuItem=%1$S wedi ei ychwanegu i %2$S
+
+# LOCALIZATION NOTE (webextPerms.sideloadHeader)
+# This string is used as a header in the webextension permissions dialog
+# when the extension is side-loaded.
+# %S is replaced with the localized name of the extension being installed.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.sideloadHeader=%S wedi ei ychwanegu
+webextPerms.sideloadText2=Mae rhaglen arall ar eich cyfrifiadur wedi gosod ychwanegiad a allai effeithio ar eich porwr. Adolygwch geisiadau caniatâd yr ychwanegyn hwn a dewiswch Galluogi neu Diddymu (i'w adael yn anabl).
+webextPerms.sideloadTextNoPerms=Mae rhaglen arall ar eich cyfrifiadur wedi gosod ychwanegyn y gall effeithio ar eich porwr. Darllenwch geisiadau caniatâd yr ychwanegyn a dewis i Alluogi neu Ddiddymu (i'w adael wedi ei analluogi).
+
+webextPerms.sideloadEnable.label=Galluogi
+webextPerms.sideloadEnable.accessKey=G
+webextPerms.sideloadCancel.label=Diddymu
+webextPerms.sideloadCancel.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.updateMenuItem)
+# %S will be replaced with the localized name of the extension which
+# has been updated.
+webextPerms.updateMenuItem=Mae %S angen caniatâd newydd
+
+# LOCALIZATION NOTE (webextPerms.updateText)
+# %S is replaced with the localized name of the updated extension.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.updateText=Mae %S wedi ei ddiweddaru. Rhaid cymeradwyo'r caniatâd newydd cyn i'r fersiwn mwy diweddar gael ei osod. Bydd dewis “Diddymu” yn cadw eich ychwanegyn cyfredol.
+
+webextPerms.updateAccept.label=Diweddaru
+webextPerms.updateAccept.accessKey=D
+
+# LOCALIZATION NOTE (webextPerms.optionalPermsHeader)
+# %S is replace with the localized name of the extension requested new
+# permissions.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.optionalPermsHeader=Mae %S yn gofyn am ganiatâd ychwanegol.
+webextPerms.optionalPermsListIntro=Mae eisiau:
+webextPerms.optionalPermsAllow.label=Caniatáu
+webextPerms.optionalPermsAllow.accessKey=C
+webextPerms.optionalPermsDeny.label=Gwrthod
+webextPerms.optionalPermsDeny.accessKey=G
+
+webextPerms.description.accountsFolders=Creu, ailenwi neu ddileu ffolderi eich cyfrif e-bost
+webextPerms.description.accountsRead=Gweld eich cyfrifon e-bost a'u ffolderi
+webextPerms.description.addressBooks=Darllenwch ac addasu eich llyfrau cyfeiriad a chysylltiadau
+webextPerms.description.bookmarks=Darllen a newid nodau tudalen
+webextPerms.description.browserSettings=Darllen a newid gosodiadau'r porwr
+webextPerms.description.browsingData=Clirio'r hanes pori diweddar, cwcis a data cysylltiedig
+webextPerms.description.clipboardRead=Estyn data o'r clipfwrdd
+webextPerms.description.clipboardWrite=Mewnbynnu data i'r clipfwrdd
+webextPerms.description.compose=Darllenwch ac addasu eich negeseuon e-bost wrth i chi eu cyfansoddi a'u hanfon
+webextPerms.description.devtools=Estyn offer datblygwyr i gael mynediad at eich data mewn tabiau agored
+webextPerms.description.dns=Manylion mynediad i IP ac enw gwesteiwr
+webextPerms.description.downloads=Llwytho i lawr, darllen ffeiliau a newid hanes llwytho i lawr y porwr
+webextPerms.description.downloads.open=Agor ffeiliau a llwythwyd i lawr i'ch cyfrifiadur
+# LOCALIZATION NOTE (webextPerms.description.experiment)
+# %S will be replaced with the name of the application
+webextPerms.description.experiment=Meddu ar fynediad llawn, heb gyfyngiad i %S, a'ch cyfrifiadur
+webextPerms.description.find=Darllen testun yr holl dabiau sydd ar agor
+webextPerms.description.geolocation=Mynediad i'ch lleoliad
+webextPerms.description.history=Mynediad at eich hanes pori
+webextPerms.description.management=Monitro'r defnydd o estyniadau a rheoli themâu
+webextPerms.description.messagesModify=Darllenwch ac addaswch eich negeseuon e-bost wrth iddyn nhw gael eu dangos i chi
+webextPerms.description.messagesMove=Symud, copïo neu ddileu eich negeseuon e-bost
+webextPerms.description.messagesRead=Darllenwch eich negeseuon e-bost a'u marcio neu eu tagio
+# LOCALIZATION NOTE (webextPerms.description.nativeMessaging)
+# %S will be replaced with the name of the application
+webextPerms.description.nativeMessaging=Cyfnewid negeseuon gyda rhaglenni ar wahân i %S
+webextPerms.description.notifications=Dangos hysbysiadau i chi
+webextPerms.description.pkcs11=Darparu gwasanaethau dilysiad cryptograffig
+webextPerms.description.privacy=Darllen a newid gosodiadau preifatrwydd
+webextPerms.description.proxy=Rheoli gosodiadau dirprwy'r porwr
+webextPerms.description.sessions=Mynediad at y tabiau caewyd yn ddiweddar
+webextPerms.description.tabs=Mynediad at dabiau'r porwyr
+webextPerms.description.tabHide=Cuddio a dangos tabiau'r porwr
+webextPerms.description.topSites=Mynediad at eich hanes pori
+webextPerms.description.unlimitedStorage=Cadw diddiwedd o swm data diddiwedd ochr y cleient
+webextPerms.description.webNavigation=Cael mynediad at weithgaredd wrth lywio
+
+webextPerms.hostDescription.allUrls=Cael mynediad i'ch data ar gyfer pob gwefan
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.wildcard)
+# %S will be replaced by the DNS domain for which a webextension
+# is requesting access (e.g., mozilla.org)
+webextPerms.hostDescription.wildcard=Cael mynediad i'ch data ym mhob gwefan ym mharth %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManyWildcards):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# domains for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManyWildcards=Peidio cael mynediad i'ch data mewn parthau eraill;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 barth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.oneSite)
+# %S will be replaced by the DNS host name for which a webextension
+# is requesting access (e.g., www.mozilla.org)
+webextPerms.hostDescription.oneSite=Cael mynediad at eich data yn %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManySites)
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# hosts for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManySites=Peidio cael mynediad i'ch data mewn gwefannau eraill;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 wefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall
+
+# LOCALIZATION NOTE (webext.defaultSearch.description)
+# %1$S is replaced with the localized named of the extension that is asking to change the default search engine.
+# %2$S is replaced with the name of the current search engine
+# %3$S is replaced with the name of the new search engine
+webext.defaultSearch.description=Mae %1$S eisiau newid eich peiriant chwilio rhagosodedig o %2$S i %3$S. Ydy hynny'n iawn?
+webext.defaultSearchYes.label=Iawn
+webext.defaultSearchYes.accessKey=I
+webext.defaultSearchNo.label=Na
+webext.defaultSearchNo.accessKey=N
+
+# LOCALIZATION NOTE (webext.remove.confirmation.title)
+# %S is the name of the extension which is about to be removed.
+webext.remove.confirmation.title=Tynnu %S
+# LOCALIZATION NOTE (webext.remove.confirmation.message)
+# %1$S is the name of the extension which is about to be removed.
+# %2$S is brandShorterName
+webext.remove.confirmation.message=Tynnu %1$S o %2$S?
+webext.remove.confirmation.button=Tynnu
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abAddressBookNameDialog.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abAddressBookNameDialog.dtd
new file mode 100644
index 0000000000..917b01a884
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abAddressBookNameDialog.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Labels -->
+
+<!ENTITY name.label      "Enw Llyfr Cyfeiriadau:">
+<!ENTITY name.accesskey  "L">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abCard.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abCard.dtd
new file mode 100644
index 0000000000..7045f4c395
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abCard.dtd
@@ -0,0 +1,156 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY Contact.tab                     "Cysylltiad">
+<!ENTITY Contact.accesskey               "C">
+<!ENTITY Name.box                        "Enw">
+
+<!-- LOCALIZATION NOTE:
+ NameField1, NameField2, PhoneticField1, PhoneticField2
+ those fields are either LN or FN depends on the target country.
+ "FirstName" and "LastName" can be swapped for id to change the order
+ but they should not be translated (same applied to phonetic id).
+ Make sure the translation of label corresponds to the order of id.
+-->
+
+<!-- LOCALIZATION NOTE (NameField1.id) : DONT_TRANSLATE -->
+<!ENTITY NameField1.id                  "FirstName">
+<!-- LOCALIZATION NOTE (NameField2.id) : DONT_TRANSLATE -->
+<!ENTITY NameField2.id                  "LastName">
+<!-- LOCALIZATION NOTE (PhoneticField1.id) : DONT_TRANSLATE -->
+<!ENTITY PhoneticField1.id              "PhoneticFirstName">
+<!-- LOCALIZATION NOTE (PhoneticField2.id) : DONT_TRANSLATE -->
+<!ENTITY PhoneticField2.id              "PhoneticLastName">
+
+<!ENTITY NameField1.label               "Cyntaf:">
+<!ENTITY NameField1.accesskey           "y">
+<!ENTITY NameField2.label               "Olaf:">
+<!ENTITY NameField2.accesskey           "O">
+<!ENTITY PhoneticField1.label           "Ffoneteg:">
+<!ENTITY PhoneticField2.label           "Ffoneteg:">
+<!ENTITY DisplayName.label              "Dangos:">
+<!ENTITY DisplayName.accesskey          "D">
+<!ENTITY preferDisplayName.label        "Dewis enw dangos o flaen pennyn neges">
+<!ENTITY preferDisplayName.accesskey    "d">
+<!ENTITY NickName.label                 "Llys Enw:">
+<!ENTITY NickName.accesskey             "L">
+
+<!ENTITY PrimaryEmail.label             "E-bost:">
+<!ENTITY PrimaryEmail.accesskey         "E">
+<!ENTITY SecondEmail.label              "E-bost Ychwanegol:">
+<!ENTITY SecondEmail.accesskey          "Y">
+<!ENTITY PreferMailFormat.label         "Dewis derbyn negeseuon wedi'u fformatio fel:">
+<!ENTITY PreferMailFormat.accesskey     "w">
+<!ENTITY PlainText.label                "Testun Plaen">
+<!ENTITY HTML.label                     "HTML">
+<!ENTITY Unknown.label                  "Anhysbys">
+<!ENTITY chatName.label                 "Enw Sgwrsio:">
+
+<!ENTITY WorkPhone.label                "Gwaith:">
+<!ENTITY WorkPhone.accesskey            "G">
+<!ENTITY HomePhone.label                "Cartref:">
+<!ENTITY HomePhone.accesskey            "C">
+<!ENTITY FaxNumber.label                "Ffacs:">
+<!ENTITY FaxNumber.accesskey            "s">
+<!ENTITY PagerNumber.label              "Swnyn:">
+<!ENTITY PagerNumber.accesskey          "w">
+<!ENTITY CellularNumber.label           "Symudol:">
+<!ENTITY CellularNumber.accesskey       "y">
+
+<!ENTITY Home.tab                       "Preifat">
+<!ENTITY Home.accesskey                 "P">
+<!ENTITY HomeAddress.label              "Cyfeiriad:">
+<!ENTITY HomeAddress.accesskey          "d">
+<!ENTITY HomeAddress2.label             "">
+<!ENTITY HomeAddress2.accesskey         "">
+<!ENTITY HomeCity.label                 "Tref/Dinas:">
+<!ENTITY HomeCity.accesskey             "T">
+<!ENTITY HomeState.label                "Sir/Talaith:">
+<!ENTITY HomeState.accesskey            "S">
+<!ENTITY HomeZipCode.label              "Cod Post/ZIP:">
+<!ENTITY HomeZipCode.accesskey          "Z">
+<!ENTITY HomeCountry.label              "Gwlad:">
+<!ENTITY HomeCountry.accesskey          "G">
+<!ENTITY HomeWebPage.label              "Tudalen We:">
+<!ENTITY HomeWebPage.accesskey          "u">
+<!ENTITY Birthday.label                 "Pen-blwydd:">
+<!ENTITY Birthday.accesskey             "P">
+<!ENTITY Month.placeholder              "Mis">
+<!ENTITY Day.placeholder                "Diwrnod">
+<!ENTITY Year.placeholder               "Blwyddyn">
+<!ENTITY Age.label                      "Oed:">
+<!ENTITY Age.placeholder                "Oed">
+
+<!ENTITY Work.tab                       "Gwaith">
+<!ENTITY Work.accesskey                 "w">
+<!ENTITY JobTitle.label                 "Teitl:">
+<!ENTITY JobTitle.accesskey             "e">
+<!ENTITY Department.label               "Adran:">
+<!ENTITY Department.accesskey           "A">
+<!ENTITY Company.label                  "Corff:">
+<!ENTITY Company.accesskey              "o">
+<!ENTITY WorkAddress.label              "Cyfeiriad:">
+<!ENTITY WorkAddress.accesskey          "y">
+<!ENTITY WorkAddress2.label             "">
+<!ENTITY WorkAddress2.accesskey         "">
+<!ENTITY WorkCity.label                 "Tref/Dinas:">
+<!ENTITY WorkCity.accesskey             "D">
+<!ENTITY WorkState.label                "Sir/Talaith:">
+<!ENTITY WorkState.accesskey            "T">
+<!ENTITY WorkZipCode.label              "Cod Post/ZIP:">
+<!ENTITY WorkZipCode.accesskey          "Z">
+<!ENTITY WorkCountry.label              "Gwlad:">
+<!ENTITY WorkCountry.accesskey          "w">
+<!ENTITY WorkWebPage.label              "Tudalen We:">
+<!ENTITY WorkWebPage.accesskey          "u">
+
+<!ENTITY Other.tab                      "Arall">
+<!ENTITY Other.accesskey                "a">
+<!ENTITY Custom1.label                  "Cyfaddasu 1:">
+<!ENTITY Custom1.accesskey              "1">
+<!ENTITY Custom2.label                  "Cyfaddasu 2:">
+<!ENTITY Custom2.accesskey              "2">
+<!ENTITY Custom3.label                  "Cyfaddasu 3:">
+<!ENTITY Custom3.accesskey              "3">
+<!ENTITY Custom4.label                  "Cyfaddasu 4:">
+<!ENTITY Custom4.accesskey              "4">
+<!ENTITY Notes.label                    "Nodiadau:">
+<!ENTITY Notes.accesskey                "N">
+
+<!ENTITY Chat.tab                       "Sgwrsio">
+<!ENTITY Chat.accesskey                 "S">
+<!ENTITY Gtalk.label                    "Google Talk:">
+<!ENTITY Gtalk.accesskey                "G">
+<!ENTITY AIM.label                      "AIM:">
+<!ENTITY AIM2.accesskey                 "M">
+<!ENTITY Yahoo.label                    "Yahoo!:">
+<!ENTITY Yahoo.accesskey                "Y">
+<!ENTITY Skype.label                    "Skype:">
+<!ENTITY Skype.accesskey                "S">
+<!ENTITY QQ.label                       "QQ:">
+<!ENTITY QQ.accesskey                   "Q">
+<!ENTITY MSN.label                      "MSN:">
+<!ENTITY MSN2.accesskey                 "N">
+<!ENTITY ICQ.label                      "ICQ:">
+<!ENTITY ICQ.accesskey                  "I">
+<!ENTITY XMPP.label                     "Jabber ID:">
+<!ENTITY XMPP.accesskey                 "J">
+<!ENTITY IRC.label                      "Llysenw IRC:">
+<!ENTITY IRC.accesskey                  "L">
+
+<!ENTITY Photo.tab                      "Ffoto">
+<!ENTITY Photo.accesskey                "o">
+<!ENTITY GenericPhoto.label             "Ffoto Generig">
+<!ENTITY GenericPhoto.accesskey         "G">
+<!ENTITY DefaultPhoto.label             "Rhagosodiad">
+<!ENTITY PhotoFile.label                "Ar y Cyfrifiadur hwn">
+<!ENTITY PhotoFile.accesskey            "A">
+<!ENTITY BrowsePhoto.label              "Pori">
+<!ENTITY BrowsePhoto.accesskey          "r">
+<!ENTITY PhotoURL.label                 "Ar y We">
+<!ENTITY PhotoURL.accesskey             "W">
+<!ENTITY PhotoURL.placeholder           "Gludo neu deipio cyfeiriad gwe'r ffoto">
+<!ENTITY UpdatePhoto.label              "Diweddaru">
+<!ENTITY UpdatePhoto.accesskey          "i">
+<!ENTITY PhotoDropTarget.label          "Llusgo ffoto newydd yma">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abContactsPanel.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abContactsPanel.dtd
new file mode 100644
index 0000000000..1117163995
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abContactsPanel.dtd
@@ -0,0 +1,49 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY propertiesMenu.label               "Priodweddau">
+<!ENTITY propertiesMenu.accesskey           "P">
+<!ENTITY propertiesCmd.key                  "i">
+<!ENTITY abPropertiesMenu.label             "Priodweddau Llyfr Cyfeiriadau">
+<!ENTITY abPropertiesMenu.accesskey         "P">
+<!ENTITY contactPropertiesMenu.label        "Priodweddau Cyswllt">
+<!ENTITY contactPropertiesMenu.accesskey    "r">
+<!ENTITY mailingListPropertiesMenu.label    "Priodweddau Rhestr E-bostio">
+<!ENTITY mailingListPropertiesMenu.accesskey "o">
+
+<!ENTITY abContextMenuButton.tooltip        "Dangos Cyd-destun Dewislen y Llyfr Cyfeiriadau">
+<!ENTITY addressbookPicker.label            "Llyfr Cyfeiriadau:">
+<!ENTITY addressbookPicker.accesskey        "L">
+<!ENTITY searchContacts.label               "Chwilio drwy'r Cysylltiadau:">
+<!ENTITY searchContacts.accesskey           "d">
+<!ENTITY SearchNameOrEmail.label            "Enw neu E-bost">
+
+<!ENTITY addtoToFieldMenu.label             "Ychwanegu i'r maes">
+<!ENTITY addtoToFieldMenu.accesskey         "m">
+<!ENTITY addtoCcFieldMenu.label             "Ychwanegu i faes Cc">
+<!ENTITY addtoCcFieldMenu.accesskey         "C">
+<!ENTITY addtoBccFieldMenu.label            "Ychwanegu i faed Bcc">
+<!ENTITY addtoBccFieldMenu.accesskey        "B">
+<!ENTITY deleteAddrBookCard.label           "Dileu">
+<!ENTITY deleteAddrBookCard.accesskey       "D">
+<!ENTITY propertiesContext.label            "Priodweddau">
+<!ENTITY propertiesContext.accesskey        "P">
+<!ENTITY abPropertiesContext.label          "Priodweddau">
+<!ENTITY abPropertiesContext.accesskey      "P">
+<!ENTITY editContactContext.label           "Golygu Cysylltiad">
+<!ENTITY editContactContext.accesskey       "G">
+<!ENTITY editMailingListContext.label       "Golygu Rhestr">
+<!ENTITY editMailingListContext.accesskey   "G">
+
+<!ENTITY newContactAbContext.label          "Cysylltiad Newydd">
+<!ENTITY newContactAbContext.accesskey      "C">
+<!ENTITY newListAbContext.label             "Rhestr Newydd">
+<!ENTITY newListAbContext.accesskey         "R">
+
+<!ENTITY toButton.label                     "Ychwanegu at:">
+<!ENTITY toButton.accesskey                 "a">
+<!ENTITY ccButton.label                     "Ychwanegu at Cc:">
+<!ENTITY ccButton.accesskey                 "C">
+<!ENTITY bccButton.label                    "Ychwanegu at Bcc:">
+<!ENTITY bccButton.accesskey                "B">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abMailListDialog.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abMailListDialog.dtd
new file mode 100644
index 0000000000..71a6610451
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abMailListDialog.dtd
@@ -0,0 +1,22 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Title -->
+
+<!ENTITY mailListWindowAdd.title        "Rhestr E-bostio Newydd">
+<!-- Labels and Access Keys -->
+
+<!ENTITY addToAddressBook.label         "Ychwanegu at: ">
+<!ENTITY addToAddressBook.accesskey     "Y">
+<!ENTITY ListName.label                 "Enw'r Rhestr: ">
+<!ENTITY ListName.accesskey             "R">
+<!ENTITY ListNickName.label             "Llys Enw'r Rhestr: ">
+<!ENTITY ListNickName.accesskey         "L">
+<!ENTITY ListDescription.label          "Disgrifiad: ">
+<!ENTITY ListDescription.accesskey      "D">
+<!-- See bug 58485, when we implement drag and drop, add 'or drag addresses' back in -->
+<!ENTITY AddressTitle.label             "Teipiwch gyfeiriadau e-bost i'w hychwanegu at y rhestr e-bostio:">
+<!ENTITY AddressTitle.accesskey         "e">
+<!ENTITY UpButton.label                 "Symud i Fyny">
+<!ENTITY DownButton.label               "Symud i Lawr">
+
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abMainWindow.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abMainWindow.dtd
new file mode 100644
index 0000000000..4eb2ead43d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abMainWindow.dtd
@@ -0,0 +1,221 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY addressbookWindow.title                        "Llyfr Cyfeiriadau">
+<!ENTITY blankResultsPaneMessage.label                  "Dim ond ar ôl chwilio mae'r llyfr cyfeiriadau hwn yn dangos cysylltiadau">
+<!ENTITY localResultsOnlyMessage.label                  "Nid yw cysylltiadau o lyfrau cyfeiriadau pell yn cael eu dangos nes eich bod yn chwilio">
+
+<!-- File Menu -->
+<!ENTITY fileMenu.label                                 "Ffeil">
+<!ENTITY fileMenu.accesskey                             "F">
+<!ENTITY newMenu.label                                  "Newydd">
+<!ENTITY newMenu.accesskey                              "N">
+<!ENTITY newContact.label                               "Cysylltiad Llyfr Cyfeiriadau…">
+<!ENTITY newContact.accesskey                           "C">
+<!ENTITY newContact.key                                 "N">
+<!ENTITY newListCmd.label                               "Rhestr E-bostio…">
+<!ENTITY newListCmd.accesskey                           "R">
+<!ENTITY newAddressBookCmd.label                        "Llyfr Cyfeiriadau…">
+<!ENTITY newAddressBookCmd.accesskey                    "L">
+<!ENTITY newCardDAVBookCmd.label                        "Llyfr Cyfeiriadau CardDAV…">
+<!ENTITY newCardDAVBookCmd.accesskey                    "V">
+<!ENTITY newLDAPDirectoryCmd.label                      "Cyfeiriadur LDAP…">
+<!ENTITY newLDAPDirectoryCmd.accesskey                  "y">
+<!ENTITY newMessageCmd.label                            "Neges">
+<!ENTITY newMessageCmd.key                              "M">
+<!ENTITY newMessageCmd.accesskey                        "N">
+<!-- LOCALIZATION NOTE (osxAddressBook) : These entities are only used on Mac -->
+<!ENTITY osxAddressBook.label                           "Defnyddio Llyfr Cyfeiriadau Mac OS X">
+<!ENTITY osxAddressBook.accesskey                       "O">
+<!ENTITY closeCmd.label                                 "Cau">
+<!ENTITY closeCmd.key                                   "W">
+<!ENTITY closeCmd.accesskey                             "u">
+<!ENTITY printSetupCmd.label                            "Gosodiad Tudalen…">
+<!ENTITY printSetupCmd.accesskey                        "u">
+<!ENTITY printPreviewContactCmd.label                   "Rhagolwg Argraffu'r Cysylltiad">
+<!ENTITY printPreviewContactCmd.accesskey               "R">
+<!ENTITY printPreviewAddressBook.label                  "Rhagolwg Argraffu Llyfr Cyfeiriadau">
+<!ENTITY printPreviewAddressBook.accesskey              "A">
+<!ENTITY printContactCmd.label                          "Argraffu'r Cysylltiad…">
+<!ENTITY printContactCmd.accesskey                      "A">
+<!ENTITY printContactCmd.key                            "P">
+<!ENTITY printAddressBook.label                         "Argraffu'r Llyfr Cyfeiriadau…">
+<!ENTITY printAddressBook.accesskey                     "L">
+
+<!-- Edit Menu -->
+<!ENTITY editMenu.label                                 "Golygu">
+<!ENTITY editMenu.accesskey                             "G">
+<!ENTITY deleteCmd.label                                "Dileu">
+<!ENTITY deleteAbCmd.label                              "Dileu Llyfr Cyfeiriadau">
+<!ENTITY deleteContactCmd.label                         "Dileu Cysylltiad">
+<!ENTITY deleteContactsCmd.label                        "Dileu Cysylltiadau">
+<!ENTITY deleteListCmd.label                            "Dileu Rhestr">
+<!ENTITY deleteListsCmd.label                           "Dileu Rhestrau">
+<!ENTITY deleteItemsCmd.label                           "Dileu Eitemau">
+<!ENTITY searchAddressesCmd.key                         "f">
+<!ENTITY propertiesMenu.label                           "Priodweddau">
+<!ENTITY propertiesMenu.accesskey                       "i">
+<!ENTITY propertiesCmd.key                              "i">
+<!ENTITY abPropertiesMenu.label                         "Priodweddau Llyfr Cyfeiriadau">
+<!ENTITY abPropertiesMenu.accesskey                     "L">
+<!ENTITY contactPropertiesMenu.label                    "Priodweddau Cyswllt">
+<!ENTITY contactPropertiesMenu.accesskey                "r">
+<!ENTITY mailingListPropertiesMenu.label                "Priodweddau Rhestr E-bostio">
+<!ENTITY mailingListPropertiesMenu.accesskey            "o">
+
+<!-- View Menu -->
+<!ENTITY viewMenu.label                                 "Golwg">
+<!ENTITY viewMenu.accesskey                             "l">
+<!ENTITY viewToolbarsMenu.label                         "Barrau Offer">
+<!ENTITY viewToolbarsMenu.accesskey                     "B">
+<!ENTITY menubarCmd.label                               "Bar Dewislen">
+<!ENTITY menubarCmd.accesskey                           "D">
+<!ENTITY showAbToolbarCmd.label                         "Bar Offer Llyfr Cyfeiriadau">
+<!ENTITY showAbToolbarCmd.accesskey                     "a">
+<!ENTITY showTaskbarCmd.label                           "Bar Statws">
+<!ENTITY showTaskbarCmd.accesskey                       "S">
+<!ENTITY customizeToolbar.label                         "Cyfaddasu…">
+<!ENTITY customizeToolbar.accesskey                     "C">
+<!ENTITY layoutMenu.label                               "Cynllun">
+<!ENTITY layoutMenu.accesskey                           "y">
+<!ENTITY showDirectoryPane.label                        "Paen Cyfeiriadur">
+<!ENTITY showDirectoryPane.accesskey                    "C">
+<!ENTITY showContactPane2.label                         "Paen Cysylltiad">
+<!ENTITY showContactPane2.accesskey                     "y">
+<!ENTITY menu_ShowNameAs.label                          "Dangos yr Enw Fel">
+<!ENTITY menu_ShowNameAs.accesskey                      "E">
+<!-- LOCALIZATION NOTE (firstLastCmd2.label): We're not including a comma here
+because displayed names don't have the comma in between. -->
+<!ENTITY firstLastCmd2.label                            "Cyntaf Olaf">
+<!ENTITY firstLastCmd2.accesskey                        "n">
+<!ENTITY lastFirstCmd.label                             "Cyntaf, Olaf">
+<!ENTITY lastFirstCmd.accesskey                         "C">
+<!ENTITY displayNameCmd.label                           "Enw Dangos">
+<!ENTITY displayNameCmd.accesskey                       "D">
+<!ENTITY sortMenu.label                                 "Trefnu yn ôl">
+<!ENTITY sortMenu.accesskey                             "T">
+
+<!-- Tools Menu -->
+<!ENTITY tasksMenu.label                                "Offer">
+<!ENTITY tasksMenu.accesskey                            "O">
+<!ENTITY messengerCmd.label                             "E-bost a Grwpiau Newyddion">
+<!ENTITY messengerCmd.accesskey                         "E">
+<!ENTITY messengerCmd.commandkey                        "1">
+<!ENTITY searchAddressesCmd.label                       "Chwilio Cyfeiriadau…">
+<!ENTITY searchAddressesCmd.accesskey                   "C">
+<!ENTITY importCmd.label                                "Mewnforio…">
+<!ENTITY importCmd.accesskey                            "M">
+<!ENTITY exportCmd.label                                "Allforio…">
+<!ENTITY exportCmd.accesskey                            "A">
+<!ENTITY preferencesCmd2.label                          "Dewisiadau">
+<!ENTITY preferencesCmd2.accesskey                      "D">
+<!ENTITY preferencesCmdUnix.label                       "Dewisiadau">
+<!ENTITY preferencesCmdUnix.accesskey                   "e">
+
+<!-- Address Book Toolbar and Context Menus -->
+<!ENTITY newContactButton.label                         "Cysylltiad Newydd">
+<!ENTITY newContactButton.accesskey                     "C">
+<!ENTITY newlistButton.label                            "Rhestr Newydd">
+<!ENTITY newlistButton.accesskey                        "R">
+<!ENTITY showAsDefault.label                            "Cyfarwyddiadur cychwyn rhagosodedig">
+<!ENTITY showAsDefault.accesskey                        "c">
+<!ENTITY editPropertiesButton.label                     "Golygu">
+<!ENTITY propertiesContext.label                        "Priodweddau">
+<!ENTITY propertiesContext.accesskey                    "i">
+<!ENTITY abPropertiesContext.label                      "Priodweddau">
+<!ENTITY abPropertiesContext.accesskey                  "i">
+<!ENTITY syncContext.label                              "Cydweddu">
+<!ENTITY syncContext.accesskey                          "C">
+<!ENTITY editContactContext.label                       "Priodweddau">
+<!ENTITY editContactContext.accesskey                   "i">
+<!ENTITY editMailingListContext.label                   "Golygu Rhestr">
+<!ENTITY editMailingListContext.accesskey               "G">
+<!ENTITY newmsgButton.label                             "Ysgrifennu">
+<!ENTITY newmsgButton.accesskey                         "Y">
+<!ENTITY newIM.label                                    "Neges Chwim">
+<!ENTITY newIM.accesskey                                "N">
+<!ENTITY printButton.label                              "Argraffu…">
+<!ENTITY printButton.accesskey                          "r">
+<!ENTITY deleteButton2.label                            "Dileu">
+<!ENTITY deleteButton2.accesskey                        "D">
+
+<!-- Address Book Toolbar Tooltips -->
+<!ENTITY columnChooser.tooltip                          "Dewiswch golofnau i'w dangos">
+<!ENTITY newContactButton.tooltip                       "Creu cysylltiad llyfr cyfeiriadau newydd">
+<!ENTITY newlistButton.tooltip                          "Creu rhestr newydd">
+<!ENTITY editPropertiesButton.tooltip                   "Golygu'r eitem hon">
+<!ENTITY editAbPropertiesButton.tooltip                 "Golygu priodweddau'r llyfr cyfeiriadau hwn">
+<!ENTITY editContactPropertiesButton.tooltip            "Golygu'r cysylltiad hwn">
+<!ENTITY editMailingListPropertiesButton.tooltip        "Golygu'r rhestr e-bostio hwn">
+<!ENTITY newmsgButton.tooltip                           "Anfon neges e-bost">
+<!ENTITY newIM.tooltip                                  "Anfon neges chwim neu sgwrs">
+<!ENTITY deleteButton2.tooltip                          "Dileu'r eitem hon">
+
+<!-- Search Bar -->
+<!ENTITY SearchNameOrEmail.label                        "Enw neu E-bost">
+<!ENTITY SearchNameOrEmail.accesskey                    "E">
+<!ENTITY advancedButton.tooltip                         "Chwilio cyfeiriadau uwch">
+<!ENTITY quickSearchCmd.key                             "k">
+<!ENTITY searchItem.title "Chwilio Cyflym">
+
+<!-- Results Pane -->
+<!ENTITY Addrbook.label                                 "Llyfr Cyfeiriadau">
+<!ENTITY Addrbook.accesskey                             "L">
+<!ENTITY GeneratedName.label                            "Enw">
+<!ENTITY GeneratedName.accesskey                        "n">
+<!ENTITY PrimaryEmail.label                             "E-bost">
+<!ENTITY PrimaryEmail.accesskey                         "b">
+<!ENTITY ChatName.label                                 "Enw Sgwrsio">
+<!ENTITY ChatName.accesskey                             "E">
+<!ENTITY Company.label                                  "Corff">
+<!ENTITY Company.accesskey                              "C">
+<!ENTITY NickName.label                                 "Llysenw">
+<!ENTITY NickName.accesskey                             "L">
+<!ENTITY SecondEmail.label                              "E-bost Ychwanegol">
+<!ENTITY SecondEmail.accesskey                          "Y">
+<!ENTITY Department.label                               "Adran">
+<!ENTITY Department.accesskey                           "A">
+<!ENTITY JobTitle.label                                 "Teitl">
+<!ENTITY JobTitle.accesskey                             "T">
+<!ENTITY CellularNumber.label                           "Symudol">
+<!ENTITY CellularNumber.accesskey                       "m">
+<!ENTITY PagerNumber.label                              "Swnyn">
+<!ENTITY PagerNumber.accesskey                          "S">
+<!ENTITY FaxNumber.label                                "Ffacs">
+<!ENTITY FaxNumber.accesskey                            "F">
+<!ENTITY HomePhone.label                                "Ffôn Cartref">
+<!ENTITY HomePhone.accesskey                            "C">
+<!ENTITY WorkPhone.label                                "Ffôn Gwaith">
+<!ENTITY WorkPhone.accesskey                            "G">
+<!ENTITY sortAscending.label                            "Esgyn">
+<!ENTITY sortAscending.accesskey                        "E">
+<!ENTITY sortDescending.label                           "Disgyn">
+<!ENTITY sortDescending.accesskey                       "D">
+<!ENTITY _PhoneticName.label                            "Enw Seinegol">
+<!ENTITY _PhoneticName.accesskey                        "S">
+
+<!-- Card Summary Pane -->
+<!-- Box Headings -->
+<!ENTITY contact.heading                                "Cysylltiad">
+<!ENTITY home.heading                                   "Cartref">
+<!ENTITY other.heading                                  "Arall">
+<!ENTITY chat.heading                                   "Sgwrsio">
+<!ENTITY phone.heading                                  "Ffôn">
+<!ENTITY work.heading                                   "Gwaith">
+<!-- Special Box Headings, for mailing lists -->
+<!ENTITY description.heading                            "Disgrifiad">
+<!ENTITY addresses.heading                              "Cyfeiriadau">
+<!-- For Map It! -->
+<!ENTITY mapItButton.label                              "Estyn Map">
+<!ENTITY mapIt.tooltip                                  "Dangos map o'r cyfeiriad o'r We">
+
+<!-- Status Bar -->
+<!ENTITY statusText.label                               "">
+
+<!--  Mac OS X Window Menu -->
+<!ENTITY windowMenu.label                               "Ffenestr">
+<!ENTITY minimizeWindow.label                           "Lleihau">
+<!ENTITY minimizeWindow.key                             "m">
+<!ENTITY bringAllToFront.label                          "Dwyn y Cyfan i'r Blaen">
+<!ENTITY zoomWindow.label                               "Chwyddo">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abNewCardDialog.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abNewCardDialog.dtd
new file mode 100644
index 0000000000..ed0e66089d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abNewCardDialog.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Labels -->
+
+<!ENTITY chooseAddressBook.label         "Ychwanegu at: ">
+<!ENTITY chooseAddressBook.accesskey     "Y">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/abResultsPane.dtd b/l10n-cy/mail/chrome/messenger/addressbook/abResultsPane.dtd
new file mode 100644
index 0000000000..6b5c4b4e9d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/abResultsPane.dtd
@@ -0,0 +1,38 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY Addrbook.label                        "Llyfr Cyfeiriadau">
+<!ENTITY Addrbook.accesskey                    "C">
+<!ENTITY GeneratedName.label                   "Enw">
+<!ENTITY GeneratedName.accesskey               "E">
+<!ENTITY PrimaryEmail.label                    "E-bost">
+<!ENTITY PrimaryEmail.accesskey                "b">
+<!ENTITY Company.label                         "Corff">
+<!ENTITY Company.accesskey                     "o">
+<!ENTITY _PhoneticName.label                   "Enw Seinegol">
+<!ENTITY _PhoneticName.accesskey               "o">
+<!ENTITY NickName.label                        "Llysenw">
+<!ENTITY NickName.accesskey                    "l">
+<!ENTITY SecondEmail.label                     "E-bost Ychwanegol">
+<!ENTITY SecondEmail.accesskey                 "b">
+<!ENTITY Department.label                      "Adran">
+<!ENTITY Department.accesskey                  "r">
+<!ENTITY JobTitle.label                        "Teitl">
+<!ENTITY JobTitle.accesskey                    "T">
+<!ENTITY CellularNumber.label                  "Symudol">
+<!ENTITY CellularNumber.accesskey              "S">
+<!ENTITY PagerNumber.label                     "Swnyn">
+<!ENTITY PagerNumber.accesskey                 "w">
+<!ENTITY FaxNumber.label                       "Ffacs">
+<!ENTITY FaxNumber.accesskey                   "F">
+<!ENTITY HomePhone.label                       "Ffôn Cartref">
+<!ENTITY HomePhone.accesskey                   "F">
+<!ENTITY WorkPhone.label                       "Ffôn Gwaith">
+<!ENTITY WorkPhone.accesskey                   "G">
+<!ENTITY ChatName.label                        "Enw Sgwrsio">
+<!ENTITY ChatName.accesskey                    "S">
+<!ENTITY sortAscending.label                   "Esgyn">
+<!ENTITY sortAscending.accesskey               "E">
+<!ENTITY sortDescending.label                  "Disgyn">
+<!ENTITY sortDescending.accesskey              "D">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/addressBook.properties b/l10n-cy/mail/chrome/messenger/addressbook/addressBook.properties
new file mode 100644
index 0000000000..9d55a0d5fb
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/addressBook.properties
@@ -0,0 +1,262 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The following are used by the Mailing list dialog.
+# LOCALIZATION NOTE (mailingListTitleEdit): %S will be replaced by the Mailing List's display name.
+mailingListTitleEdit=Golygu %S
+emptyListName=Rhaid cyflwyno enw rhestr.
+badListNameCharacters=Nid yw enw rhestr yn gallu cynnwys unrhyw un o'r nodau canlynol: < > ; , "
+badListNameSpaces=Nid yw enw rhestr yn gallu cynnwys nifer o fylchau cyfagos.
+lastFirstFormat=%S, %S
+firstLastFormat=%S, %S
+
+allAddressBooks=Pob Llyfr Cyfeiriadau
+
+newContactTitle=Cysylltiad Newydd
+# %S will be the contact's display name
+newContactTitleWithDisplayName=Cysylltiad newydd %S
+editContactTitle=Golygu Cysylltiad
+# %S will be the contact's display name
+editContactTitleWithDisplayName=Golygu Cysylltiad %S
+# don't translate vCard
+editVCardTitle=Golygu vCard
+# %S will be the card's display name, don't translate vCard
+editVCardTitleWithDisplayName=Golygu vCard %S
+
+## LOCALIZATION NOTE (cardRequiredDataMissingMessage):  do not localize \n
+cardRequiredDataMissingMessage=Rhaid rhoi o leiaf un o'r eitemau canlynol:\nCyfeiriad e-bost, Enw Cyntaf, Enw Olaf, Enw Dangos, Corff.
+cardRequiredDataMissingTitle=Mae Gwybodaeth Angenrheidiol ar Goll
+incorrectEmailAddressFormatMessage=Rhaid i'r prif gyfeiriad fod ar ffurf defnyddiwr@gwesteiwr.
+incorrectEmailAddressFormatTitle=Fformat Cyfeiriad Anghywir
+
+viewListTitle=Rhestr E-bostio: %S
+mailListNameExistsTitle=Rhestr E-bostio'n Bodoli Eisoes
+mailListNameExistsMessage=Mae Rhestr E-bostio o'r enw yna'n bodoli eisoes. Dewiswch enw arall.
+
+confirmDeleteThisContactTitle=Dileu Cysylltiad
+# LOCALIZATION NOTE (confirmDeleteThisContact):
+# #1 The name of the selected contact
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: Are you sure you want to delete this contact?
+#          • John Doe
+confirmDeleteThisContact=Ydych chi'n siŵr eich bod eisiau dileu'r cysylltiad?\n• #1
+
+confirmDelete2orMoreContactsTitle=Dileu Cysylltiadau Lluosog
+# LOCALIZATION NOTE (confirmDelete2orMoreContacts):
+# Semicolon list of plural forms.
+# See: https://developer.mozilla.org/docs/Localization_and_Plurals
+# #1 The number of selected contacts, always more than 1.
+# Example: Are you sure you want to delete these 3 contacts?
+confirmDelete2orMoreContacts=Peidio dileu'r cysylltiadau yma?;Ydych chi'n siŵr eich bod am ddileu'r #1 cysylltiad yma?;Ydych chi'n siŵr eich bod am ddileu'r #1 gysylltiad yma?;Ydych chi'n siŵr eich bod am ddileu'r #1 chysylltiad yma?;Ydych chi'n siŵr eich bod am ddileu'r #1 chysylltiad yma?;Ydych chi'n siŵr eich bod am ddileu'r #1 cysylltiad yma?
+
+confirmRemoveThisContactTitle=Tynnu Cysylltiad
+# LOCALIZATION NOTE (confirmRemoveThisContact):
+# #1 The name of the selected contact
+# #2 The name of the containing mailing list
+# This title is about a contact in a mailing list, so it will not be deleted,
+# but only removed from the list.
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: Are you sure you want to remove this contact from the mailing list 'Customers List'?
+#          • John Doe
+confirmRemoveThisContact=Ydych chi'n siŵr eich bod am dynnu'r cysylltiad hwn o rhestr e-bostio '#2'?\n• #1
+
+confirmRemove2orMoreContactsTitle=Tynnu Cysylltiadau Lluosog
+# LOCALIZATION NOTE (confirmRemove2orMoreContacts):
+# Semicolon list of singular and plural forms.
+# See: https://developer.mozilla.org/docs/Localization_and_Plurals
+# #1 The number of selected contacts, always more than 1.
+# #2 The name of the containing mailing list
+# Example: Are you sure you want to remove these 3 contacts from the mailing list 'Customers List'?
+confirmRemove2orMoreContacts=Peidio tynnu'r cysylltiadau yma;Ydych chi'n siŵr eich bod am dynnu'r #1 cysylltiad yma o restr e-bostio '#2'?;Ydych chi'n siŵr eich bod am dynnu'r #1 gysylltiad yma o restr e-bostio '#2'?;Ydych chi'n siŵr eich bod am dynnu'r #1 chysylltiad yma o restr e-bostio '#2'?;Ydych chi'n siŵr eich bod am dynnu'r #1 chysylltiad yma o restr e-bostio '#2'?;Ydych chi'n siŵr eich bod am dynnu'r #1 cysylltiad yma o restr e-bostio '#2'?
+
+confirmDeleteThisMailingListTitle=Dileu Rhestr E-bost
+# LOCALIZATION NOTE (confirmDeleteThisMailingList):
+# #1 The name of the selected mailing list
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: Are you sure you want to delete this mailing list?
+#          • Customers List
+confirmDeleteThisMailingList=Ydych chi'n siŵr eich bod eisiau dileu'r rhestr e-bostio hwn?\n• #1
+
+confirmDelete2orMoreMailingListsTitle=Dileu Rhestrau E-bostio Lluosog
+# LOCALIZATION NOTE (confirmDelete2orMoreMailingLists):
+# Semicolon list of plural forms.
+# See: https://developer.mozilla.org/docs/Localization_and_Plurals
+# #1 The number of selected mailing lists, always more than 1
+# Example: Are you sure you want to delete these 3 mailing lists?
+confirmDelete2orMoreMailingLists=Peidio dileu'r rhestrau e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr e-bostio?Ydych chi'n siŵr eich bod am ddileu #1 restr e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 restr e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 restr e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 restr e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 restr e-bostio?
+
+confirmDelete2orMoreContactsAndListsTitle=Dileu Rhestrau Cysylltiadau ac E-bostio
+# LOCALIZATION NOTE (confirmDelete2orMoreContactsAndLists):
+# Semicolon list of and plural forms.
+# See: https://developer.mozilla.org/docs/Localization_and_Plurals
+# #1 The number of selected contacts and mailing lists, always more than 1
+# Example: Are you sure you want to delete these 3 contacts and mailing lists?
+confirmDelete2orMoreContactsAndLists=Peidio dileu rhestrau cysylltiadau ac e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr cysylltiadau ac e-bostio?Ydych chi'n siŵr eich bod am ddileu #1 restr cysylltiadau ac e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr cysylltiadau ac e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr cysylltiadau ac e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr cysylltiadau ac e-bostio?;Ydych chi'n siŵr eich bod am ddileu #1 rhestr cysylltiadau ac e-bostio?
+
+confirmDeleteThisAddressbookTitle=Dileu Llyfr Cyfeiriadau
+# LOCALIZATION NOTE (confirmDeleteThisAddressbookTitle):
+# #1 The name of the selected address book
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: Are you sure you want to delete this address book and all of its contacts?
+#          • Friends and Family Address Book
+confirmDeleteThisAddressbook=Ydych chi'n siŵr eich bod am ddileu'r llyfr cyfeiriadau a'r holl gysylltiadau?\n• #1
+
+confirmDeleteThisLDAPDirTitle=Dileu Cyfeiriadur LDAP Lleol
+# LOCALIZATION NOTE (confirmDeleteThisLDAPDir):
+# #1 The name of the selected LDAP directory
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: Are you sure you want to delete the local copy of this LDAP directory and all of its offline contacts?
+#          • Mozilla LDAP Directory
+confirmDeleteThisLDAPDir=Ydych chi'n siŵr eich bod am ddileu copi lleol yr cyfeiriadur LDAP a'i holl gynnwys all-lein i gyd?\n• #1
+
+confirmDeleteThisCollectionAddressbookTitle=Dileu Casgliad Llyfr Cyfeiriadau
+# LOCALIZATION NOTE (confirmDeleteThisCollectionAddressbook):
+# #1 The name of the selected collection address book
+# #2 The name of the application (Thunderbird)
+# Don't localize "\n• #1" unless your local layout comes out wrong.
+# Example: If this address book is deleted, Thunderbird will no longer collect addresses.
+#          Are you sure you want to delete this address book and all of its contacts?
+#          • My Collecting Addressbook
+confirmDeleteThisCollectionAddressbook=Os bydd y llyfr cyfeiriadau'n cael eu dileu, bydd #2 ddim yn casglu cyfeiriadau wedyn.\nYdych chi'n siŵr eich bod chi eisiau dileu'r llyfr cyfeiriaduron hwn a'i gysylltiadau i gyd?\n• #1
+
+propertyPrimaryEmail=E-bost
+propertyListName=Enw Rhestr
+propertySecondaryEmail=E-bost Ychwanegol
+propertyNickname=Llysenw
+propertyDisplayName=Enw Dangos
+propertyWork=Gwaith
+propertyHome=Cartref
+propertyFax=Ffacs
+propertyCellular=Symudol
+propertyPager=Swnyn
+propertyBirthday=Pen-blwydd
+propertyCustom1=Cyfaddasu 1
+propertyCustom2=Cyfaddasu 2
+propertyCustom3=Cyfaddas 3
+propertyCustom4=Cyfaddasu 4
+
+propertyGtalk=Google Talk
+propertyAIM=AIM
+propertyYahoo=Yahoo!
+propertySkype=Skype
+propertyQQ=QQ
+propertyMSN=MSN
+propertyICQ=ICQ
+propertyXMPP=Enw Jabber
+propertyIRC=Llysenw IRC
+
+## LOCALIZATION NOTE (cityAndStateAndZip):
+## %1$S is city, %2$S is state, %3$S is zip
+cityAndStateAndZip=%1$S, %2$S %3$S
+## LOCALIZATION NOTE (cityAndStateNoZip):
+## %1$S is city, %2$S is state
+cityAndStateNoZip=%1$S, %2$S
+## LOCALIZATION NOTE (cityOrStateAndZip):
+## %1$S is city or state, %2$S is zip
+cityOrStateAndZip=%1$S %2$S
+
+stateZipSeparator=
+
+prefixTo=At
+prefixCc=Cc
+prefixBcc=Bcc
+addressBook=Llyfr Cyfeiriadau
+
+# Contact photo management
+browsePhoto=Llun y Cysylltiad
+stateImageSave=Cadw'r ddelwedd…
+errorInvalidUri=Gwall: delwedd ffynhonnell annilys.
+errorNotAvailable=Gwall: nid oes modd cysylltu â'r ffeil.
+errorInvalidImage=Gwall: Dim ond delweddau JPG, PNG a GIF sy'n cael eu cynnal.
+errorSaveOperation=Gwall: Methu cadw'r ddelwedd.
+
+# mailnews.js
+ldap_2.servers.pab.description=Llyfr Cyfeiriadau Personol
+ldap_2.servers.history.description=Cyfeiriadau wedi'u Casglu
+## LOCALIZATION NOTE (ldap_2.servers.osx.description is only used on Mac OS X)
+ldap_2.servers.osx.description=Llyfr Cyfeiriadau Mac OS X
+
+# status bar stuff
+## LOCALIZATION NOTE (totalContactStatus):
+## %1$S is address book name, %2$S is contact count
+totalContactStatus=Pob cysylltiad yn %1$S: %2$S
+noMatchFound=Heb ganfod cydweddion
+## LOCALIZATION NOTE (matchesFound1):
+## Semicolon-separated list of singular and plural forms.
+## See: https://developer.mozilla.org/docs/Mozilla/Localization/Localization_and_Plurals
+## #1 is the number of matching contacts found
+matchesFound1=Heb ganfod dim cydweddiadau;Wedi canfod #1 sy'n cydweddu;Wedi canfod #1 sy'n cydweddu;Wedi canfod #1 sy'n cydweddu;Wedi canfod #1 sy'n cydweddu;Wedi canfod #1 sy'n cydweddu
+
+## LOCALIZATION NOTE (contactsCopied): Semi-colon list of plural forms
+## %1$S is the number of contacts that were copied. This should be used multiple
+## times wherever you need it. Do not replace by %S.
+contactsCopied=%1$S cysylltiad wedi'i gopïo%1$S cysylltiadau wedi'u copïo
+
+## LOCALIZATION NOTE (contactsMoved): Semi-colon list of plural forms
+## %1$S is the number of contacts that were moved. This should be used multiple
+## times wherever you need it. Do not replace by %S.
+contactsMoved=%1$S cysylltiad wedi'i symud%1$S cysylltiadau wedi'u symud
+
+# LDAP directory stuff
+invalidName=Rhoi Enw dilys.
+invalidHostname=Rhowch Enw Gwesteiwr dilys.
+invalidPortNumber=Rhowch Rif Porth dilys.
+invalidResults=Rhowch rif dilys ym maes y canlyniadau.
+abReplicationOfflineWarning=Rhaid bod ar-lein i ddyblygu LDAP.
+abReplicationSaveSettings=Rhaid cadw gosodiadau cyn bod modd llwytho i lawr.
+
+# For importing / exporting
+## LOCALIZATION NOTE (ExportAddressBookNameTitle): %S is the name of exported addressbook
+ExportAddressBookNameTitle=Allforio Llyfr Cyfeiriadau - %S
+LDIFFiles=LDIF
+CSVFiles=Gwahanwyd gan Atalnod
+CSVFilesSysCharset=Gwahanwyd gan Atalnod (Set Nod y System)
+CSVFilesUTF8=Gwahanwyd gan Atalnod (UTF-8)
+TABFiles=Diderfyn Tab
+TABFilesSysCharset=Diderfyn Tab (Set Nod y System)
+TABFilesUTF8=Diderfyn Tab (UTF-8)
+VCFFiles=vCard
+SupportedABFiles=Ffeiliau Llyfr Cyfeiriad sy'n Cael eu Cynnal
+failedToExportTitle=Methodd Allforio
+failedToExportMessageNoDeviceSpace=Methodd allforio'r llyfr cyfeiriadau, dim lle ar y ddyfais.
+failedToExportMessageFileAccessDenied=Methodd allforio'r llyfr cyfeiriadau, gwrthodwyd mynediad i'r ffeil.
+
+# For getting authDN for replication using dlg box
+AuthDlgTitle=Dyblygu Llyfr Cyfeiriadau LDAP
+AuthDlgDesc=I gael mynediad i weinydd y cyfeiriadur, rhowch eich enw defnyddiwr a chyfrinair.
+
+# LOCALIZATION NOTE(joinMeInThisChat)
+# use + for spaces
+joinMeInThisChat=Ymuno+â+mi+yn+y+Sgwrs.
+
+# For printing
+headingHome=Cartref
+headingWork=Gwaith
+headingOther=Arall
+headingChat=Sgwrsio
+headingPhone=Ffôn
+headingDescription=Disgrifiad
+headingAddresses=Cyfeiriadau
+
+## For address books
+addressBookTitleNew=Llyfr Cyfeiriadau Newydd
+# LOCALIZATION NOTE (addressBookTitleEdit):
+# %S is the current name of the address book.
+# Example: My Custom AB Properties
+addressBookTitleEdit=Priodweddau %S
+duplicateNameTitle=Enw Llyfr Cyfeiriadau Dyblyg
+# LOCALIZATION NOTE (duplicateNameText):
+# Don't localize "\n• %S" unless your local layout comes out wrong.
+# %S is the name of the existing address book.
+# Example: An address book with this name already exists:
+#          • My Custom AB
+duplicateNameText=Mae llyfr cyfeiriadau gyda'r enw hwn yn bodoli eisoes:\n %S
+
+# For corrupt .mab files
+corruptMabFileTitle=Ffeil Llyfr Cyfeiriadau Llwgr
+corruptMabFileAlert=Methu darllen un o ffeiliau llyfr cyfeiriadau (%1$S file). Bydd ffeil %2$S newydd yn cael ei greu yn yr un cyfeiriadur a chopi wrth gefn o'r enw %3$S.
+
+# For locked .mab files
+lockedMabFileTitle=Methu Llwytho Ffeil Llyfr Cyfeiriadau
+lockedMabFileAlert=Methu llwytho ffeil llyfr cyfeiriadau %S. Gall fod yn darllen yn unig, neu wedi ei gloi gan raglen arall. Ceisiwch eto yn ddiweddarach.
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/ldapAutoCompErrs.properties b/l10n-cy/mail/chrome/messenger/addressbook/ldapAutoCompErrs.properties
new file mode 100644
index 0000000000..096f8e817a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/ldapAutoCompErrs.properties
@@ -0,0 +1,109 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# These are error strings for problems that happen while in the
+# various states declared in nsILDAPAutoCompFormatter.idl.  Note that
+# the number that indexes each error state is the same as the number 
+# corresponding to that state in nsILDAPAutoCompFormatter.idl.
+
+# These are error strings for problems that happen while in the
+# various states declared in nsILDAPAutoCompFormatter.idl.  Note that
+# the number that indexes each error state is the same as the number
+# corresponding to that state in nsILDAPAutoCompFormatter.idl.
+
+## @name ERR_STATE_UNBOUND
+## @loc none
+0=Anhawster cychwyn LDAP
+
+## @name ERR_STATE_INITIALIZING
+## @loc none
+1=Methodd cysylltiad gweinydd LDAP
+
+## @name ERR_STATE_BINDING
+## @loc none
+2=Methodd cysylltiad gweinydd LDAP
+
+## @name ERR_STATE_BOUND
+## @loc none
+3=Problem cyfathrebu gweinydd LDAP
+
+## @name ERR_STATE_SEARCHING
+## @loc none
+4=Problem chwilio gweinydd LDAP
+
+
+# The format of the alert dialog itself
+#
+## @name ALERT_FORMAT
+## @loc None of %1$S, %2$S and %3$S should be localized. 
+##      %1$S is the error code itself, %2$S is an LDAP SDK error message from
+##      chrome://mozldap/locale/ldap.properties, and %3$S is a hint relating
+##      to that specific error, found in this file.
+errorAlertFormat=Cod gwall %1$S: %2$S\n\n %3$S
+
+## The following errors are for error codes other than LDAP-specific ones.
+## Someday mozilla will actually have a system for mapping nsresults to
+## error strings that's actually widely used, unlike nsIErrorService.  But
+## until it does, these strings live here...
+
+## @name HOST_NOT_FOUND
+## @loc none
+5000=Methu canfod gwesteiwr
+
+## @name GENERIC_ERROR
+## @loc none
+9999=Gwall anhysbys
+
+
+# Hints to for the user, associated with specific error codes (ie error code
+# + 10000)
+
+
+## @name TIMELIMIT_EXCEEDED_HINT
+## @loc none
+10003=Ceisiwch eto yn ddiweddarach neu cysylltwch â'ch Gweinyddwr System.
+
+## @name STRONGAUTH_REQUIRED_HINT
+## @loc none
+10008=Nid yw dilysu cryf yn cael ei gynnal ar hyn o bryd.
+
+## @name INVALID_SYNTAX_HINT
+## @loc none
+10021=Gwiriwch fod yr hidl chwilio'n gywir a cheisiwch eto, neu cysylltwch â'ch Gweinyddwr System. I wirio fod yr hidl chwilio'n gywir, o'r ddewislen Golygu dewiswch Dewis ac yna dewis E-bost a Grwpiau Newyddion ac yna dewis Cyfeirio. Cliciwch ar Golygu Cyfeiriaduron a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch ar Golygu ac yna clicio ar Uwch i ddangos yr Hidl Chwilio.
+
+## @name NO_SUCH_OBJECT_HINT
+## @loc none
+10032=Gwiriwch fod y Base DN yn gywir a cheisiwch eto, neu cysylltwch â'ch Gweinyddwr System. I wirio fod y Base DN yn gywir, o'r ddewislen Golygu dewiswch Dewisiadau, yna E-bost a Grwpiau Newyddion, dewis Cyfeirio. Cliciwch Golygu Cyfeiriaduron, a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch Golygu i ddangos Base DN.
+
+## @name BUSY_HINT
+## @loc none
+10051=Ceisiwch eto'n ddiweddarach.
+
+## @name SERVER_DOWN_HINT
+## @loc none
+10081=Gwiriwch fod Enw Gwesteiwr a Rhif Porth yn gywir a cheisiwch eto neu cysylltwch â'ch Gweinyddwr System. I wirio fod yr Enw Gwesteiwr a'r Rhif Porth cywir, o'r ddewislen Golygu dewiswch Dewisiadau, yna E-bost a Grwpiau Newyddion, dewis Cyfeirio. Cliciwch Golygu Cyfeiriaduron, a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch Golygu i ddangos yr Enw gwesteiwr. Cliciwch Uwch i ddangos Rhif y Porth.
+
+## @name TIMEOUT_HINT
+## @loc none
+10085=Ceisiwch eto'n ddiweddarach.
+
+## @name FILTER_ERROR_HINT
+## @loc none
+10087=Gwiriwch fod yr hidl chwilio'n gywir a cheisiwch eto, neu cysylltwch a'ch Gweinyddwr System. I wirio fod yr hidl chwilio'n gywir, o'r ddewislen Golygu dewiswch Dewis ac yna dewis E-bost a Grwpiau Newyddion ac yna dewis Cyfeirio. Cliciwch ar Golygu Cyfeiriaduron a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch ar Golygu ac yna clicio ar Uwch i ddangos yr Hidl Chwilio.
+
+## @name NO_MEMORY_HINT
+## @loc none
+10090=Caewch rhai ffenestri eraill a/neu gymwysiadau a cheisiwch eto.
+
+## @name CONNECT_ERROR_HINT
+## @loc none
+10091=Gwiriwch fod Enw Gwesteiwr a Rhif Porth yn gywir a cheisiwch eto neu cysylltwch â'ch Gweinyddwr System. I wirio fod yr Enw Gwesteiwr a'r Rhif Porth cywir, o'r ddewislen Golygu dewiswch Dewisiadau, yna E-bost a Grwpiau Newyddion, dewis Cyfeirio. Cliciwch Golygu Cyfeiriaduron, a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch Golygu i ddangos yr Enw gwesteiwr. Cliciwch Uwch i ddangos Rhif y Porth.
+
+## @name HOST_NOT_FOUND_HINT
+## @loc none
+15000=Gwiriwch fod Enw Gwesteiwr yn gywir a cheisiwch eto neu cysylltwch â'ch Gweinyddwr System. I wirio fod yr Enw Gwesteiwr cywir, o'r ddewislen Golygu dewiswch Dewisiadau, yna E-bost a Grwpiau Newyddion, dewis Cyfeirio. Clicio Golygu Cyfeiriaduron, a dewis y gweinydd LDAP sy'n cael ei ddefnyddio. Cliciwch Golygu i ddangos yr Enw Gwesteiwr.
+
+## @name GENERIC_HINT
+## @loc none
+19999=Cysylltwch â'ch Gweinyddwr System.
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/pref-directory-add.dtd b/l10n-cy/mail/chrome/messenger/addressbook/pref-directory-add.dtd
new file mode 100644
index 0000000000..4e18369be7
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/pref-directory-add.dtd
@@ -0,0 +1,45 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY directoryName.label               "Enw: ">
+<!ENTITY directoryName.accesskey           "E">
+<!ENTITY directoryHostname.label           "Enw Gwesteiwr: ">
+<!ENTITY directoryHostname.accesskey       "G">
+<!ENTITY directoryBaseDN.label             "DN Bôn: ">
+<!ENTITY directoryBaseDN.accesskey         "B">
+<!ENTITY findButton.label                  "Canfod">
+<!ENTITY findButton.accesskey              "f">
+<!ENTITY directorySecure.label             "Defnyddio cysylltiad diogel (SSL)">
+<!ENTITY directorySecure.accesskey         "D">
+<!ENTITY directoryLogin.label              "Rhwymo DN: ">
+<!ENTITY directoryLogin.accesskey          "R">
+<!ENTITY General.tab                       "Cyffredinol">
+<!ENTITY Offline.tab                       "All-lein">
+<!ENTITY Advanced.tab                      "Uwch">
+<!ENTITY portNumber.label                  "Rhif porth: ">
+<!ENTITY portNumber.accesskey              "p">
+<!ENTITY searchFilter.label                "Hidl chwilio: ">
+<!ENTITY searchFilter.accesskey            "H">
+<!ENTITY scope.label                       "Amrediad: ">
+<!ENTITY scope.accesskey                   "A">
+<!ENTITY scopeOneLevel.label               "Un Lefel">
+<!ENTITY scopeOneLevel.accesskey           "U">
+<!ENTITY scopeSubtree.label                "Is-goeden">
+<!ENTITY scopeSubtree.accesskey            "I">
+<!ENTITY return.label                      "Peidio dychwelyd mwy na">
+<!ENTITY return.accesskey                  "P">
+<!ENTITY results.label                     "canlyniadau">
+<!ENTITY offlineText.label                 "Gallwch lwytho i lawr copi lleol o'r cyfeiriadur hwn ar gyfer defnydd all-lein.">
+<!ENTITY saslMechanism.label               "Dull mewngofnodi: ">
+<!ENTITY saslMechanism.accesskey           "m">
+<!ENTITY saslOff.label                     "Syml">
+<!ENTITY saslOff.accesskey                 "S">
+<!ENTITY saslGSSAPI.label                  "Kerberos (GSSAPI)">
+<!ENTITY saslGSSAPI.accesskey              "K">
+<!-- Localization note: this is here because the width of the dialog 
+     is determined by the width of the base DN box; and that is likely
+     to vary somewhat with the language.
+-->
+
+<!ENTITY newDirectoryWidth                 "36em">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/pref-directory.dtd b/l10n-cy/mail/chrome/messenger/addressbook/pref-directory.dtd
new file mode 100644
index 0000000000..93db1fa36e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/pref-directory.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (window.title) : do not translate "LDAP" in below line -->
+
+<!ENTITY pref.ldap.window.title    "Gweinyddion Cyfeiriadur LDAP">
+<!-- LOCALIZATION NOTE (directories.label) : do not translate "LDAP" in below line -->
+<!ENTITY directories.label         "Gweinyddwyr Cyfeiriadur LDAP:">
+<!-- LOCALIZATION NOTE (directoriesText.label) : do not translate "LDAP" in below line -->
+<!ENTITY directoriesText.label     "Dewiswch Gyfeiriadur gweinydd LDAP:">
+<!ENTITY directoriesText.accesskey "D">
+<!ENTITY addDirectory.label        "Ychwanegu">
+<!ENTITY addDirectory.accesskey    "Y">
+<!ENTITY editDirectory.label       "Golygu">
+<!ENTITY editDirectory.accesskey   "G">
+<!ENTITY deleteDirectory.label     "Dileu">
+<!ENTITY deleteDirectory.accesskey "D">
diff --git a/l10n-cy/mail/chrome/messenger/addressbook/replicationProgress.properties b/l10n-cy/mail/chrome/messenger/addressbook/replicationProgress.properties
new file mode 100644
index 0000000000..26a24ca271
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/addressbook/replicationProgress.properties
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+replicationStarted=Dyblygu wedi cychwyn…
+changesStarted=Wedi cychwyn canfod newidiadau i'w dyblygu…
+replicationSucceeded=Llwyddodd y dyblygu
+replicationFailed=Methodd y dyblygu
+replicationCancelled=Diddymwyd y dyblygu
+# LOCALIZATION NOTE
+# do not localize %S.  %S is the current entry number (an integer)
+currentCount=Dyblygu cofnod cyfeiriadur: %S
+
+downloadButton=Llwytho i Lawr Nawr
+downloadButton.accesskey=L
+cancelDownloadButton=Diddymu Llwytho i Lawr
+cancelDownloadButton.accesskey=D
+
+directoryTitleNew=Cyfeiriadur LDAP Newydd
+## LOCALIZATION NOTE (directoryTitleEdit): %S will be replaced by the LDAP directory's display name
+directoryTitleEdit=Priodweddau %S
diff --git a/l10n-cy/mail/chrome/messenger/am-addressing.dtd b/l10n-cy/mail/chrome/messenger/am-addressing.dtd
new file mode 100644
index 0000000000..bb0c68dce8
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-addressing.dtd
@@ -0,0 +1,51 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from am-addressing.xul -->
+
+<!-- extracted from am-addressing.xhtml -->
+
+<!ENTITY addressing.label          "Ysgrifennu a Chyfeiriadau">
+<!ENTITY addressingGroupTitle.label "Cyfeirio">
+<!ENTITY addressingText.label      "Wrth chwilio am gyfeiriadau:">
+<!-- LOCALIZATION NOTE (override.label) : do not translate "LDAP" in below line -->
+<!ENTITY useGlobal.label           "Defnyddio fy newisiadau gweinydd LDAP eang ar gyfer y cyfrif hwn">
+<!ENTITY useGlobal.accesskey       "D">
+<!ENTITY editDirectories.label     "Golygu Cyfeiriaduron…">
+<!ENTITY editDirectories.accesskey "C">
+<!-- LOCALIZATION NOTE (directories.label) : do not translate "LDAP" in below line -->
+<!ENTITY directories.label         "Defnyddio gweinydd LDAP gwahanol:">
+<!ENTITY directories.accesskey     "D">
+<!ENTITY directoriesNone.label     "Dim">
+
+<!-- am-addressing.xul -->
+
+<!-- am-addressing.xhtml -->
+
+<!ENTITY compositionGroupTitle.label          "Ysgrifennu">
+<!-- LOCALIZATION NOTE (useHtml.label) : do not translate "html" in below line -->
+<!ENTITY useHtml.label                        "Ysgrifennu negeseuon yn fformat HTML">
+<!ENTITY useHtml.accesskey                    "Y">
+<!ENTITY autoQuote.label                      "Dyfynnu'r neges wreiddiol yn awtomatig wrth ateb">
+<!ENTITY autoQuote.accesskey                  "D">
+<!-- LOCALIZATION NOTE (quoting.label): This will concatenate with the 4 strings that follow. -->
+<!ENTITY quoting.label                        "Pan yn dyfynnu">
+<!ENTITY quoting.accesskey                    "d">
+<!ENTITY aboveQuote.label                     "cychwyn fy ateb uwchlaw'r dyfyniad">
+<!ENTITY belowQuote.label                     "cychwyn fy ateb o dan y dyfyniad">
+<!ENTITY selectAndQuote.label                 "dewis y dyfyniad">
+<!ENTITY place.label                          "a gosod fy llofnod">
+<!ENTITY place.accesskey                      "l">
+<!ENTITY belowText.label                      "islaw'r dyfyniad (argymhellir)">
+<!ENTITY aboveText.label                      "o dan fy ateb (uwchlaw'r dyfyniad)">
+<!ENTITY includeSigOnReply.label              "Cynnwys llofnod mewn atebion">
+<!ENTITY includeSigOnReply.accesskey          "a">
+<!ENTITY includeSigOnForward.label            "Cynnwys llofnod wrth anfon ymlaen">
+<!ENTITY includeSigOnForward.accesskey        "y">
+
+<!ENTITY globalComposingPrefs.label           "Dewisiadau Cyfansoddi Eang…">
+<!ENTITY globalComposingPrefs.accesskey       "D">
+
+<!ENTITY globalAddressingPrefs.label          "Dewisiadau Cyfansoddi Eang…">
+<!ENTITY globalAddressingPrefs.accesskey      "C">
diff --git a/l10n-cy/mail/chrome/messenger/am-advanced.dtd b/l10n-cy/mail/chrome/messenger/am-advanced.dtd
new file mode 100644
index 0000000000..763eaaa5b6
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-advanced.dtd
@@ -0,0 +1,31 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from am-advanced.xul -->
+<!-- LOCALIZATION NOTE (smtpServer.label): do not translate "SMTP" in below line -->
+
+
+<!-- extracted from am-advanced.xhtml -->
+
+<!ENTITY smtpServer.label "Gosodiadau Gweinydd Anfon (SMTP)">
+<!-- LOCALIZATION NOTE (smtpDescription.label): do not translate "SMTP" in below line -->
+
+<!ENTITY smtpDescription.label "Wrth reoli eich hunaniaethau mae modd defnyddio gweinydd o&apos;r rhestr hon drwy ei dewis fel y Gweinydd Anfon (SMTP) neu mae modd defnyddio&apos;r gweinydd rhagosodedig o&apos;r rhestr hon drwy ddewis &quot;Defnyddio&apos;r Gweinydd Rhagosodedig&quot;.">
+
+<!ENTITY smtpListAdd.label  "Ychwanegu…">
+<!ENTITY smtpListAdd.accesskey  "Y">
+<!ENTITY smtpListEdit.label "Golygu…">
+<!ENTITY smtpListEdit.accesskey "G">
+<!ENTITY smtpListDelete.label "Tynnu">
+<!ENTITY smtpListDelete.accesskey "T">
+<!ENTITY smtpListSetDefault.label "Gosod y Rhagosodiad">
+<!ENTITY smtpListSetDefault.accesskey "R">
+
+<!ENTITY serverDetails.label "Manylion y gweinydd hwn:">
+<!ENTITY serverDescription.label "Disgrifiad: ">
+<!ENTITY serverName.label "Enw'r Gweinydd: ">
+<!ENTITY serverPort.label "Porth: ">
+<!ENTITY userName.label   "Enw Defnyddiwr: ">
+<!ENTITY connectionSecurity.label "Diogelwch y Cysylltiad: ">
+<!ENTITY authMethod.label   "Dull dilysu: ">
diff --git a/l10n-cy/mail/chrome/messenger/am-archiveoptions.dtd b/l10n-cy/mail/chrome/messenger/am-archiveoptions.dtd
new file mode 100644
index 0000000000..b1517343ce
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-archiveoptions.dtd
@@ -0,0 +1,26 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from am-archiveoptions.xul -->
+
+
+<!-- extracted from am-archiveoptions.xhtml -->
+
+<!ENTITY dialogTitle.label "Dewisiadau Archifo">
+<!ENTITY archiveGranularityPrefix.label "Wrth archifo negeseuon, eu rhoi yn:">
+<!ENTITY archiveFlat.label "Ffolder unigol">
+<!ENTITY archiveFlat.accesskey "u">
+<!ENTITY archiveYearly.label "Ffolderi archif blynyddol">
+<!ENTITY archiveYearly.accesskey "b">
+<!ENTITY archiveMonthly.label "Ffolderi archif misol">
+<!ENTITY archiveMonthly.accesskey "m">
+<!ENTITY keepFolderStructure.label "Cadw strwythur cyfredol ffolderi negeseuon archifwyd">
+<!ENTITY keepFolderStructure.accesskey "s">
+<!ENTITY archiveExample.label "Esiampl">
+<!-- LOCALIZATION NOTE (archiveFolderName.label): this should match the default
+     name for the "Archives" folder -->
+<!ENTITY archiveFolderName.label "Archifau">
+<!-- LOCALIZATION NOTE (inboxFolderName.label): this should match the default
+     name for the "Inbox" folder -->
+<!ENTITY inboxFolderName.label "Derbyn">
diff --git a/l10n-cy/mail/chrome/messenger/am-copies.dtd b/l10n-cy/mail/chrome/messenger/am-copies.dtd
new file mode 100644
index 0000000000..d791632db6
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-copies.dtd
@@ -0,0 +1,53 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from am-copies.xul -->
+
+
+<!-- extracted from am-copies.xhtml -->
+
+<!ENTITY copyAndFolderTitle.label "Copïau a Ffolderi">
+<!ENTITY sendingPrefix.label "Wrth anfon negeseuon, yn awtomatig: ">
+<!ENTITY fccMailFolder.label "Rhoi copi yn:">
+<!ENTITY fccMailFolder.accesskey "c">
+<!ENTITY fccReplyFollowsParent.label "Rhoi atebion yn ffolder y negeseuon sy'n derbyn ateb">
+<!ENTITY fccReplyFollowsParent.accesskey "a">
+<!-- LOCALIZATION NOTE (ccAddress.label): do not translate "Cc" in below line -->
+<!ENTITY ccAddress.label "Cc y cyfeiriadau e-bost hyn:">
+<!ENTITY ccAddress.accesskey "C">
+<!ENTITY ccAddressList.placeholder "Gwahanu cyfeiriad gyda chollnod">
+<!-- LOCALIZATION NOTE (bccAddress.label): do not translate "Bcc" in below line -->
+<!ENTITY bccAddress.label "Bcc y cyfeiriadau e-bost hyn:">
+<!ENTITY bccAddress.accesskey "B">
+<!ENTITY bccAddressList.placeholder "Gwahanu cyfeiriad gyda chollnod">
+<!ENTITY saveMessageDlg.label "Dangos deialog cadarnhau wrth i negeseuon gael eu cadw">
+<!ENTITY saveMessageDlg.accesskey "g">
+<!-- LOCALIZATION NOTE (sentFolderOn.label): OK to translate this, bug #57440 -->
+<!ENTITY sentFolderOn.label "Ffolder &quot;Anfonwyd&quot; ar:">
+<!ENTITY sentFolderOn.accesskey "n">
+<!ENTITY sentInOtherFolder.label "Arall:">
+<!ENTITY sentInOtherFolder.accesskey "A">
+<!-- LOCALIZATION NOTE (archivesFolderOn.label): OK to translate this, bug #57440 -->
+<!ENTITY archivesTitle.label "Archif Negeseuon">
+<!ENTITY keepArchives.label "Cadw archif negeseuon yn:">
+<!ENTITY keepArchives.accesskey "a">
+<!ENTITY archiveHierarchyButton.label "Dewisiadau archifo…">
+<!ENTITY archiveHierarchyButton.accesskey "w">
+<!ENTITY archivesFolderOn.label "Ffolder &quot;Archif&quot; yn:">
+<!ENTITY archivesFolderOn.accesskey "F">
+<!ENTITY archiveInOtherFolder.label "Arall:">
+<!ENTITY archiveInOtherFolder.accesskey "r">
+<!ENTITY specialFolders.label "Drafftiau a Thempledi">
+<!ENTITY keepDrafts2.label "Cadw negeseuon drafft yn:">
+<!-- LOCALIZATION NOTE (draftsFolderOn.label): OK to translate this, bug #57440 -->
+<!ENTITY draftsFolderOn.label "Ffolder &quot;Drafftiau&quot; yn:">
+<!ENTITY draftsFolderOn.accesskey "D">
+<!ENTITY draftInOtherFolder.label "Arall:">
+<!ENTITY draftInOtherFolder.accesskey "l">
+<!ENTITY keepTemplates.label "Cadw templedi negeseuon yn:">
+<!-- LOCALIZATION NOTE (templatesFolderOn.label): OK to translate this, bug #57440 -->
+<!ENTITY templatesFolderOn.label "Ffolder &quot;Templedi&quot; yn:">
+<!ENTITY templatesFolderOn.accesskey "T">
+<!ENTITY templateInOtherFolder.label "Arall:">
+<!ENTITY templateInOtherFolder.accesskey "r">
diff --git a/l10n-cy/mail/chrome/messenger/am-e2e.properties b/l10n-cy/mail/chrome/messenger/am-e2e.properties
new file mode 100644
index 0000000000..dbc7881dde
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-e2e.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+prefPanel-e2e=Amgryptio Pen-i-Ben
diff --git a/l10n-cy/mail/chrome/messenger/am-identities-list.dtd b/l10n-cy/mail/chrome/messenger/am-identities-list.dtd
new file mode 100644
index 0000000000..24527f0212
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-identities-list.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY identitiesListManageDesc.label "Rheoli hunaniaethau'r cyfrif hwn. Bydd yr hunaniaeth gyntaf yn cael ei ddefnyddio drwy ragosodiad.">
+<!ENTITY identitiesListAdd.label  "Ychwanegu…">
+<!ENTITY identitiesListAdd.accesskey  "Y">
+<!ENTITY identitiesListEdit.label "Golygu…">
+<!ENTITY identitiesListEdit.accesskey "G">
+<!ENTITY identitiesListDefault.label "Gosod y Rhagosodiad">
+<!ENTITY identitiesListDefault.accesskey "R">
+<!ENTITY identitiesListDelete.label "Dileu">
+<!ENTITY identitiesListDelete.accesskey "D">
+<!ENTITY identitiesListClose.label "Cau">
+<!ENTITY identitiesListClose.accesskey "u">
diff --git a/l10n-cy/mail/chrome/messenger/am-identity-edit.dtd b/l10n-cy/mail/chrome/messenger/am-identity-edit.dtd
new file mode 100644
index 0000000000..ceb7e18e09
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-identity-edit.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (identityDialog.style): This value should be roughly
+     equal to the value of accountManager.size entity minus the value
+     of accountTree.width entity. -->
+
+<!ENTITY identityListDesc.label "Ffurfweddu gosodiadau'r hunaniaeth yma:">
+
+<!ENTITY settingsTab.label       "Gosodiadau">
+<!ENTITY copiesFoldersTab.label "Copïau a Ffolderi">
+<!ENTITY addressingTab.label    "Ysgrifennu a Chyfeiriadau">
+
+<!ENTITY publicData.label        "Data Cyhoeddus">
+<!ENTITY privateData.label       "Data Preifat">
+<!ENTITY identityAlias.label     "Label Hunaniaeth:">
+<!ENTITY identityAlias.accesskey "H">
diff --git a/l10n-cy/mail/chrome/messenger/am-im.dtd b/l10n-cy/mail/chrome/messenger/am-im.dtd
new file mode 100644
index 0000000000..f06259ec14
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-im.dtd
@@ -0,0 +1,16 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY accountWindow.title           "Priodweddau cyfrif">
+<!ENTITY accountWindow.width           "300">
+<!ENTITY account.general               "Cyffredinol">
+<!ENTITY account.advanced              "Dewisiadau Uwch">
+<!ENTITY account.name                  "Enw Defnyddiwr:">
+<!ENTITY account.password              "Cyfrinair:">
+<!ENTITY account.alias                 "Enw arall:">
+<!ENTITY account.newMailNotification   "Hysbysu ar E-bost newydd">
+<!ENTITY account.autojoin              "Sianeli Awto-Gyfuno:">
+<!ENTITY account.proxySettings.caption "Gosodiadau Dirprwyol:">
+<!ENTITY account.proxySettings.change.label     "Newid…">
+<!ENTITY account.proxySettings.change.accessKey "N">
diff --git a/l10n-cy/mail/chrome/messenger/am-junk.dtd b/l10n-cy/mail/chrome/messenger/am-junk.dtd
new file mode 100644
index 0000000000..d50ab0e944
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-junk.dtd
@@ -0,0 +1,31 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY junkSettings.label "Gosodiadau Sbam">
+<!ENTITY trainingDescription.label "Os yw wedi'i alluogi, bydd rhaid i chi ddysgu &brandShortName; i adnabod sbam drwy ddefnyddio'r botwm bar offer Sbam i farcio negeseuon fel sbam neu beidio. Rhaid i chi adnabod negeseuon sbam a'r rhai nad ydynt yn sbam. Wedyn bydd &brandShortName; yn gallu nodi sbam yn awtomatig.">
+<!ENTITY level.label "Galluogi rheolaeth addasol e-bost sbam ar gyfer y cyfrif hwn">
+<!ENTITY level.accesskey "s">
+
+<!ENTITY move.label "Symud sbam newydd i:">
+<!ENTITY move.accesskey "S">
+<!ENTITY junkFolderOn.label "Ffolder &quot;Sbam&quot; yn:">
+<!ENTITY junkFolderOn.accesskey "F">
+<!ENTITY otherFolder.label "Arall:">
+<!ENTITY otherFolder.accesskey "a">
+<!ENTITY purge1.label "Dileu'n awtomatig sbam hŷn na">
+<!ENTITY purge1.accesskey "D">
+<!ENTITY purge2.label "diwrnod">
+
+<!ENTITY whitelistHeader.label "Peidio marcio e-bost fel sbam yn awtomatig os yw'r anfonwr yn: ">
+<!ENTITY whitelistHeader.accesskey "P">
+
+<!ENTITY ispHeadersWarning.label "Os wedi ei alluogi bydd &brandShortName; yn ystyried yn awtomatig fod negeseuon wedi eu marcio gan y dosbarthydd allanol yn sbam.">
+<!ENTITY ispHeaders.label "Ymddiried ym mhenynnau e-bost sbam wedi'u gosod gan: ">
+<!ENTITY ispHeaders.accesskey "Y">
+
+<!ENTITY junkClassification.label "Dewis">
+<!ENTITY junkActions.label "Cyrchfan a Chadw">
+
+<!ENTITY globalJunkPrefs.label "Dewisiadau Sbam Eang…">
+<!ENTITY globalJunkPrefs.accesskey "E">
diff --git a/l10n-cy/mail/chrome/messenger/am-main.dtd b/l10n-cy/mail/chrome/messenger/am-main.dtd
new file mode 100644
index 0000000000..18b5ecfc62
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-main.dtd
@@ -0,0 +1,49 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from am-main.xul -->
+
+<!-- extracted from am-main.xhtml -->
+
+<!ENTITY accountTitle.label "Gosodiadau'r Cyfrif">
+<!ENTITY accountName.label "Enw Cyfrif:">
+<!ENTITY accountName.accesskey "C">
+<!ENTITY identityTitle.label "Hunaniaeth Rhagosodedig">
+<!ENTITY identityDesc.label "Mae gan bob cyfrif hunaniaeth, sef y wybodaeth mae pobl eraill yn ei weld pan yn darllen eich negeseuon.">
+<!ENTITY name.label "Eich Enw:">
+<!ENTITY name.accesskey "E">
+<!ENTITY email.label "Cyfeiriad E-bost:">
+<!ENTITY email.accesskey "y">
+<!ENTITY catchAll.label "Ymateb o'r hunaniaeth hon pan fydd y penynnau dosbarthu yn cyfateb:">
+<!ENTITY catchAll.accesskey "d">
+<!ENTITY replyTo.label "Cyfeiriad Ateb Iddo:">
+<!ENTITY replyTo.accesskey "A">
+<!ENTITY replyTo.placeholder "Derbynwyr i ateb i gyfeiriad arall">
+<!ENTITY organization.label "Corff:">
+<!ENTITY organization.accesskey "o">
+<!ENTITY signatureText.label "Testun llofnod:">
+<!ENTITY signatureText.accesskey "T">
+<!ENTITY signatureHtml.label "Defnyddio HTML (e.e., &lt;b&gt;trwm&lt;/b&gt;)">
+<!ENTITY signatureHtml.accesskey "H">
+<!ENTITY signatureFile.label "Atodi llofnod o ffeil (testun, HTML neu ddelwedd):">
+<!ENTITY signatureFile.accesskey "A">
+<!ENTITY edit.label "Golygu…">
+<!ENTITY choose.label "Dewis…">
+<!ENTITY choose.accesskey "D">
+<!ENTITY editVCard.label "Golygu Cerdyn…">
+<!ENTITY editVCard.accesskey "G">
+<!-- LOCALIZATION NOTE (attachVCard.label) : do not translate "vCard" in below line -->
+<!ENTITY attachVCard.label "Atodi fy vCard i negeseuon">
+<!ENTITY attachVCard.accesskey "v">
+
+<!ENTITY manageIdentities.label "Rheoli Hunaniaeth…">
+<!ENTITY manageIdentities.accesskey "H">
+
+<!-- LOCALIZATION NOTE (smtpName.label) : do not translate "SMTP" in below line -->
+<!ENTITY smtpName.label "Gweinydd Anfon (SMTP):">
+<!ENTITY smtpName.accesskey "A">
+<!ENTITY smtpDefaultServer.label "Defnyddio'r Gweinydd Rhagosodedig">
+
+<!ENTITY smtpServerEdit.label "Golygu gweinydd SMTP…">
+<!ENTITY smtpServerEdit.accesskey "S">
diff --git a/l10n-cy/mail/chrome/messenger/am-mdn.dtd b/l10n-cy/mail/chrome/messenger/am-mdn.dtd
new file mode 100644
index 0000000000..c98c1e4473
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-mdn.dtd
@@ -0,0 +1,33 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY pane.title                   "Derbynebau Dychwelyd">
+<!ENTITY useGlobalPrefs.label         "Defnyddio fy newisiadau derbynneb dychwelyd ar gyfer y cyfrif hwn">
+<!ENTITY useGlobalPrefs.accesskey     "D">
+<!ENTITY globalReceipts.label         "Dewisiadau Eang…">
+<!ENTITY globalReceipts.accesskey     "E">
+<!ENTITY useCustomPrefs.label         "Cyfaddasu derbynebau dychwelyd ar gyfer y cyfrif hwn">
+<!ENTITY useCustomPrefs.accesskey     "C">
+<!ENTITY requestReceipt.label         "Wrth anfon negeseuon, gofyn bob tro am dderbynneb dychwelyd">
+<!ENTITY requestReceipt.accesskey     "W">
+<!ENTITY receiptArrive.label          "Pan fydd derbynneb yn cyrraedd:">
+<!ENTITY leaveIt.label                "Gadael yn fy Mlwch Derbyn">
+<!ENTITY leaveIt.accesskey            "D">
+<!-- LOCALIZATION NOTE moveToSent.label Translate: 'Sent' according to Netscape glossary -->
+<!ENTITY moveToSent.label             "Symud i fy ffolder &quot;Anfonwyd&quot;">
+<!ENTITY moveToSent.accesskey         "A">
+<!ENTITY requestMDN.label             "Pan fyddaf yn derbyn cais am dderbynneb dychwelyd:">
+<!ENTITY returnSome.label             "Caniatáu derbynebau dychwelyd ar gyfer rhai negeseuon">
+<!ENTITY returnSome.accesskey         "a">
+<!ENTITY never.label                  "Peidio byth anfon derbynneb dychwelyd">
+<!ENTITY never.accesskey              "P">
+<!ENTITY notInToCc.label              "Os nad wyf yn At neu Cc y neges:">
+<!ENTITY notInToCc.accesskey          "O">
+<!ENTITY outsideDomain.label          "Os yw'r anfonwr o'r tu allan i'm parth:">
+<!ENTITY outsideDomain.accesskey      "s">
+<!ENTITY otherCases.label             "Mewn unrhyw achos arall:">
+<!ENTITY otherCases.accesskey         "M">
+<!ENTITY askMe.label                  "Gofyn i mi">
+<!ENTITY alwaysSend.label             "Anfon pob tro">
+<!ENTITY neverSend.label              "Byth anfon">
diff --git a/l10n-cy/mail/chrome/messenger/am-mdn.properties b/l10n-cy/mail/chrome/messenger/am-mdn.properties
new file mode 100644
index 0000000000..26c43e5a61
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-mdn.properties
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## Strings used in prefs.
+prefPanel-mdn=Derbynebau Dychwelyd
diff --git a/l10n-cy/mail/chrome/messenger/am-offline.dtd b/l10n-cy/mail/chrome/messenger/am-offline.dtd
new file mode 100644
index 0000000000..9bafc66069
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-offline.dtd
@@ -0,0 +1,57 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY doNotDownloadPop3Movemail.label "I arbed lle, peidio llwytho i lawr:">
+<!ENTITY doNotDownloadNntp.label "I arbed lle, peidio llwytho i lawr ar gyfer defnydd all-lein:">
+<!ENTITY doNotDownloadImap.label "I arbed lle ar ddisg, mae modd cyfyngu ar lwytho i lawr negeseuon o'r gweinydd a chadw copïau lleol yn ôl oed a maint.">
+<!ENTITY allFoldersOffline2.label "Cadw negesuon ym mhob ffolder ar gyfer y cyfrif yma ar y cyfrifiadur hwn">
+<!ENTITY allFoldersOffline2.accesskey "h">
+<!ENTITY allFoldersOfflineNote.label "Sylw: Bydd newid hwn yn effeithio ar holl ffolderi'r cyfrif hwn. I osod ffolderi unigol, defnyddiwch y botwm Uwch….">
+<!ENTITY offlineNotDownload.label "Negeseuon mwy na">
+<!ENTITY offlineNotDownload.accesskey "N">
+<!ENTITY autosyncNotDownload.label "Peidio llwytho i lawr negeseuon mwy na">
+<!ENTITY autosyncNotDownload.accesskey "P">
+<!ENTITY kb.label "KB">
+<!ENTITY daysOld.label "diwrnod oed">
+<!ENTITY message.label "negeseuon">
+<!ENTITY nntpNotDownloadRead.label "Darllen negeseuon">
+<!ENTITY nntpNotDownloadRead.accesskey "D">
+<!ENTITY nntpDownloadMsg.label "Negeseuon mwy na">
+<!ENTITY nntpDownloadMsg.accesskey "e">
+<!ENTITY retentionCleanup.label "I adfer lle ar ddisg, mae modd dileu hen negesuon yn barhaol.">
+<!ENTITY retentionCleanupImap.label "I adfer lle ar ddisg, mae modd dileu hen negeseuon yn barhaol yn gopïau lleol a'r gwreiddiol ar y gweinydd pell.">
+<!ENTITY retentionCleanupPop.label "I adfer lle ar ddisg, mae modd dileu hen negeseuon yn barhaol gan gynnwys y gwreiddiol ar y gweinydd pell.">
+<!ENTITY retentionKeepMsg.label "Dileu negeseuon sy'n fwy na">
+<!ENTITY retentionKeepMsg.accesskey "D">
+<!ENTITY retentionKeepAll.label "Peidio dileu unrhyw negeseuon">
+<!ENTITY retentionKeepAll.accesskey "e">
+<!ENTITY retentionKeepRecent.label "Dileu pob un heblaw'r mwyaf diweddar">
+<!ENTITY retentionKeepRecent.accesskey "i">
+<!ENTITY retentionApplyToFlagged.label "Cadw negeseuon serennog bob tro">
+<!ENTITY retentionApplyToFlagged.accesskey "s">
+<!ENTITY nntpRemoveMsgBody.label "Tynnu corff neges mwy na">
+<!ENTITY nntpRemoveMsgBody.accesskey "c">
+<!ENTITY offlineSelectNntp.label "Dewis grwpiau newyddion ar gyfer defnydd all-lein…">
+<!ENTITY offlineSelectNntp.accesskey "g">
+<!ENTITY offlineImapAdvancedOffline.label "Uwch…">
+<!ENTITY offlineImapAdvancedOffline.accesskey "U">
+<!ENTITY syncGroupTitle.label "Cydweddu Negeseuon">
+<!ENTITY diskspaceGroupTitle.label "Lle ar Ddisg">
+
+<!-- LOCALIZATION NOTE: (ageAutosyncBefore.label, ageAutosyncMiddle.label, ageAutosyncAfter.label):
+  The entities ageAutosyncBefore.label, ageAutosyncMiddle.label, and ageAutosyncAfter.label appear
+  on a single line within the scope of useAutosync.ByAge as follows:
+
+  &ageAutosyncBefore.label [textbox for autosync value] &ageAutosyncMiddle.label; [dropdown for autosync interval] &ageAutosyncAfter.label;
+-->
+<!ENTITY allAutosync.label               "Cydweddu pob neges yn lleol beth bynnag yw eu hoed">
+<!ENTITY allAutosync.accesskey           "C">
+<!ENTITY ageAutosyncBefore.label         "Cydweddu'r mwyaf diweddar">
+<!ENTITY ageAutosync.accesskey           "z">
+<!ENTITY ageAutosyncMiddle.label         "">
+<!ENTITY dayAgeInterval.label            "Diwrnod">
+<!ENTITY weekAgeInterval.label           "Wythnos">
+<!ENTITY monthAgeInterval.label          "Mis">
+<!ENTITY yearAgeInterval.label           "Blwyddyn">
+<!ENTITY ageAutosyncAfter.label          "">
diff --git a/l10n-cy/mail/chrome/messenger/am-server-advanced.dtd b/l10n-cy/mail/chrome/messenger/am-server-advanced.dtd
new file mode 100644
index 0000000000..5159965a50
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-server-advanced.dtd
@@ -0,0 +1,31 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY serverAdvanced.label "Gosodiadau Cyfrif Uwch">
+<!-- LOCALIZATION NOTE (serverDirectory.label): Do not translate "IMAP" -->
+<!ENTITY serverDirectory.label "Cyfeiriadur gweinydd IMAP:">
+<!ENTITY serverDirectory.accesskey "g">
+<!ENTITY usingSubscription.label "Dangos ffolderi tanysgrifiwyd iddynt">
+<!ENTITY usingSubscription.accesskey "t">
+<!ENTITY dualUseFolders.label "Mae'r gweinydd yn cynnal ffolderi sy'n cynnwys is-ffolderi a negeseuon">
+<!ENTITY dualUseFolders.accesskey "f">
+<!ENTITY maximumConnectionsNumber.label "Uchafswm cysylltiadau gweinydd i'r storfa">
+<!ENTITY maximumConnectionsNumber.accesskey "U">
+<!-- LOCALIZATION NOTE (namespaceDesc.label): Do not translate "IMAP" -->
+<!ENTITY namespaceDesc.label "Mae'r dewisiadau yn pennu bwlchenw ar eich gweinydd IMAP">
+<!ENTITY personalNamespace.label "Bwlchenw personol:">
+<!ENTITY personalNamespace.accesskey "B">
+<!ENTITY publicNamespace.label "Cyhoeddus (rhannu):">
+<!ENTITY publicNamespace.accesskey "y">
+<!ENTITY otherUsersNamespace.label "Defnyddwyr Eraill:">
+<!ENTITY otherUsersNamespace.accesskey "D">
+<!ENTITY overrideNamespaces.label "Caniatáu i'r gweinydd i wrth-wneud y bylchau enw">
+<!ENTITY overrideNamespaces.accesskey "C">
+<!ENTITY pop3DeferringDesc.label "Wrth lwytho e-bost i lawr o weinydd y cyfrif, defnyddiwch y ffolder ganlynol i gadw'r negeseuon newydd:" >
+<!ENTITY accountInbox.label "Blwch Derbyn y cyfrif hwn">
+<!ENTITY accountInbox.accesskey "c">
+<!ENTITY deferToServer.label "Blwch Derbyn cyfrif gwahanol">
+<!ENTITY deferToServer.accesskey "g">
+<!ENTITY deferGetNewMail.label "Cynnwys y gweinydd hwn wrth estyn e-byst newydd">
+<!ENTITY deferGetNewMail.accesskey "y">
diff --git a/l10n-cy/mail/chrome/messenger/am-server-top.dtd b/l10n-cy/mail/chrome/messenger/am-server-top.dtd
new file mode 100644
index 0000000000..6c4a69823e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-server-top.dtd
@@ -0,0 +1,89 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY messageStorage.label "Storfa Negeseuon">
+<!ENTITY securitySettings.label "Gosodiadau Diogelwch">
+<!ENTITY serverSettings.label "Gosodiadau'r Gweinydd">
+<!ENTITY serverType.label "Math o Weinydd:">
+<!ENTITY serverName.label "Enw'r Gweinydd:">
+<!ENTITY serverName.accesskey "G">
+<!ENTITY userName.label "Enw Defnyddiwr:">
+<!ENTITY userName.accesskey "D">
+<!ENTITY port.label "Porth:">
+<!ENTITY port.accesskey "P">
+<!ENTITY serverPortDefault.label "Rhagosodiad:">
+<!-- LOCALIZATION NOTE (biffStart.label) : translate below 2 line with grammar dependency
+        For example, in Japanese cases:
+                biffStart.label "every"
+                biffEnd.label   "minutes for new messages Check"
+-->
+<!ENTITY biffStart.label "Gwirio am negeseuon newydd bob ">
+<!ENTITY biffStart.accesskey "w">
+<!ENTITY biffEnd.label "munud">
+<!ENTITY useIdleNotifications.label "Caniatáu hysbysiadau gweinydd di-oed wrth i negeseuon newydd gyrraedd">
+<!ENTITY useIdleNotifications.accesskey "a">
+<!ENTITY connectionSecurity.label "Diogelwch y cysylltiad:">
+<!ENTITY connectionSecurity.accesskey "D">
+<!ENTITY connectionSecurityType-0.label "Dim">
+<!ENTITY connectionSecurityType-1.label "STARTTLS, os ar gael">
+<!ENTITY connectionSecurityType-2.label "STARTTLS">
+<!ENTITY connectionSecurityType-3.label "SSL/TLS">
+<!ENTITY authMethod.label "Dull dilysu:">
+<!ENTITY authMethod.accesskey "u">
+<!ENTITY leaveOnServer.label "Gadael negeseuon ar y gweinydd">
+<!ENTITY leaveOnServer.accesskey "a">
+<!ENTITY headersOnly.label "Estyn penynnau'n unig">
+<!ENTITY headersOnly.accesskey "p">
+<!ENTITY deleteByAgeFromServer.label "Ar y mwyaf">
+<!ENTITY deleteByAgeFromServer.accesskey "m">
+<!ENTITY daysEnd.label "diwrnod">
+<!ENTITY deleteOnServer2.label "Nes i mi eu dileu">
+<!ENTITY deleteOnServer2.accesskey "d">
+<!ENTITY downloadOnBiff.label "Llwytho i lawr negeseuon newydd yn awtomatig">
+<!ENTITY downloadOnBiff.accesskey "a">
+<!ENTITY deleteMessagePrefix.label "Pan fyddaf yn dileu neges:">
+<!ENTITY modelMoveToTrash.label "Ei symud i'r ffolder yma:">
+<!ENTITY modelMoveToTrash.accesskey "y">
+<!ENTITY modelMarkDeleted.label "Marcio fel ei fod wedi'i ddileu">
+<!ENTITY modelMarkDeleted.accesskey "M">
+<!ENTITY modelDeleteImmediately.label "Diddymu'n syth">
+<!ENTITY modelDeleteImmediately.accesskey "i">
+<!-- LOCALIZATION NOTE (expungeOnExit.label) : do not translate two of "&quot;" in below line -->
+<!ENTITY expungeOnExit.label "Glanhau&apos;r (&quot;Expunge&quot;) Blwch Derbyn wrth Adael">
+<!ENTITY expungeOnExit.accesskey "G">
+<!ENTITY emptyTrashOnExit.label "Gwagio'r Sbwriel wrth Adael">
+<!ENTITY emptyTrashOnExit.accesskey "A">
+<!ENTITY loginAtStartup.label "Gwirio am negeseuon newydd wrth gychwyn">
+<!ENTITY loginAtStartup.accesskey "w">
+<!-- LOCALIZATION NOTE (maxMessagesStart.label) : translate below 2 lines with grammar dependency
+    maxMessengerStart.label will be followed by maxMessagesEnd.label with the number
+    of messages between them
+-->
+<!ENTITY maxMessagesStart.label "Gofyn cyn llwytho i lawr mwy na">
+<!ENTITY maxMessagesStart.accesskey "o">
+<!-- LOCALIZATION NOTE (maxMessagesEnd.label) : see note for maxMessagesStart.label -->
+<!ENTITY maxMessagesEnd.label "neges">
+<!ENTITY alwaysAuthenticate.label "Gofyn bob tro am ddilysiad wrth gysylltu â'r gweinydd hwn">
+<!ENTITY alwaysAuthenticate.accesskey "b">
+<!ENTITY newsrcFilePath1.label "Ffeil News.rc:">
+<!ENTITY newsrcPicker1.label "Dewis Ffeil News.rc">
+<!ENTITY abbreviate.label "Dangos enwau'r grŵp newyddion yn y paen Ffolder E-bost, fel:">
+<!ENTITY abbreviateOn.label "Enwau llawn (e.e, 'netscape.public.mozilla.mail-news')">
+<!ENTITY abbreviateOff.label "Enwau byr (e.e. 'n.p.m.mail-news')">
+<!ENTITY advancedButton.label "Uwch…">
+<!ENTITY advancedButton.accesskey "U">
+<!ENTITY serverDefaultCharset2.label "Amgodiad Testun Rhagosodedig:">
+<!ENTITY localPath1.label "Cyfeiriadur Lleol:">
+<!ENTITY localFolderPicker.label "Dewis Cyfeiriadur Lleol">
+<!ENTITY browseFolder.label "Pori…">
+<!ENTITY browseFolder.accesskey "P">
+<!ENTITY browseNewsrc.label "Pori…">
+<!ENTITY browseNewsrc.accesskey "o">
+
+<!ENTITY accountTitle.label "Gosodiadau Cyfrif">
+<!ENTITY accountSettingsDesc.label "Mae hwn yn gyfrif arbennig.  Nid oes hunaniaethau wedi'u cysylltu ag ef.">
+<!ENTITY storeType.label "Math o Storio Negeseuon:">
+<!ENTITY storeType.accesskey "S">
+<!ENTITY mboxStore2.label "Ffeil i'r ffolder (mbox)">
+<!ENTITY maildirStore.label "Ffeil y neges (maildir)">
diff --git a/l10n-cy/mail/chrome/messenger/am-serverwithnoidentities.dtd b/l10n-cy/mail/chrome/messenger/am-serverwithnoidentities.dtd
new file mode 100644
index 0000000000..af82c6f129
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-serverwithnoidentities.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY accountName.label "Enw Cyfrif:">
+<!ENTITY accountName.accesskey "C">
diff --git a/l10n-cy/mail/chrome/messenger/am-smime.dtd b/l10n-cy/mail/chrome/messenger/am-smime.dtd
new file mode 100644
index 0000000000..ed21a7ceb9
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-smime.dtd
@@ -0,0 +1,55 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY e2eTitle.label "Amgryptio Pen-i-Ben">
+<!ENTITY e2eLearnMore.label "Dysgu rhagor">
+
+<!ENTITY e2eEnc.description "Heb amgryptio pen-i-ben mae cynnwys negeseuon yn hawdd eu hamlygu i'ch darparwr e-bost ac i wyliadwriaeth dorfol.">
+<!ENTITY e2eeReqWarning.description "Os oes angen amgryptio arnoch, er mwyn anfon neges mae'n rhaid bod gennych allwedd gyhoeddus neu dystysgrif pob derbynnydd.">
+
+<!ENTITY e2eSigning.description "Mae llofnod digidol yn caniatáu i dderbynwyr wirio bod y neges wedi'i hanfon gennych chi, ac nad yw'r cynnwys wedi'i newid.">
+<!ENTITY e2eTechPref.description "Y dewis o dechnoleg amgryptio:">
+
+<!ENTITY doNotEncrypt.label "Peidio â galluogi amgryptio yn rhagosodedig">
+<!ENTITY doNotEncrypt.accesskey "P">
+<!ENTITY requireEncryptMessage.label "Defnyddio amgryptio yn rhagosodedig">
+<!ENTITY requireEncryptMessage.accesskey "D">
+<!ENTITY encryptionCert2.message "Tystysgrif bersonol ar gyfer amgryptio:">
+<!ENTITY digitalSign.certificate.button "Dewis…">
+<!ENTITY digitalSign.certificate.accesskey "S">
+<!ENTITY digitalSign.certificate_clear.button "Clirio">
+<!ENTITY digitalSign.certificate_clear.accesskey "C">
+<!ENTITY encryption.certificate.button "Dewis…">
+<!ENTITY encryption.certificate.accesskey "w">
+<!ENTITY encryption.certificate_clear.button "Clirio">
+<!ENTITY encryption.certificate_clear.accesskey "l">
+<!ENTITY signingGroupTitle.label "Llofnodi Digidol">
+<!ENTITY signMessage2.label "Ychwanegu fy llofnod ddigidol yn rhagosodedig">
+<!ENTITY signMessage.accesskey "r">
+
+<!ENTITY signingCert2.message "Tystysgrif bersonol ar gyfer amgryptio:">
+
+<!ENTITY sendingDefaults.label "Gosodiadau rhagosodedig ar gyfer anfon negeseuon">
+
+<!ENTITY technologyAutomatic.label "Dewis yn awtomatig ar sail yr allweddi neu'r tystysgrifau sydd ar gael">
+
+<!ENTITY certificates2.label "S/MIME">
+<!ENTITY manageCerts3.label "Rheoli Tystysgrifau S/MIME">
+<!ENTITY manageCerts3.accesskey "M">
+<!ENTITY manageDevices2.label "Dyfeisiau Diogelwch S/MIME">
+<!ENTITY manageDevices2.accesskey "y">
+
+<!ENTITY technologySMIME.label "Dewis S/MIME">
+<!ENTITY technologyOpenPGP.label "Dewis OpenPGP">
+
+<!ENTITY openpgpKeys.label "OpenPGP">
+
+<!-- Strings for the cert picker dialog -->
+<!ENTITY certPicker.title "Dewis Tystysgrif">
+<!ENTITY certPicker.info  "Tystysgrif:">
+<!ENTITY certPicker.detailsLabel "Manylion y dystysgrif hon:">
+
+<!ENTITY openpgpKey.message "Allwedd bersonol ar gyfer amgryptio a llofnodi digidol:">
+<!ENTITY openpgpKey.button "Gosod Allwedd Bersonol…">
+<!ENTITY openpgpKey.accesskey "G">
diff --git a/l10n-cy/mail/chrome/messenger/am-smime.properties b/l10n-cy/mail/chrome/messenger/am-smime.properties
new file mode 100644
index 0000000000..27fd773de7
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/am-smime.properties
@@ -0,0 +1,39 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## S/MIME error strings.
+## Note to localization: %S is a placeholder
+NoSenderSigningCert=Rydych wedi nodi y dylai'r neges fod wedi'i llofnodi'n ddigidol, ond un ai methodd y rhaglen a chanfod y dystysgrif llofnodwyd ac a enwyd yn Gosodiadau eich E-bost a Grŵp newyddion neu mae'r dystysgrif wedi dod i ben.
+NoSenderEncryptionCert=Rydych wedi pennu amgryptiad ar gyfer y neges, ond un ai methodd y rhaglen ganfod y dystysgrif amgryptio nodwyd yn eich Gosodiadau Cyfrif E-bost a Grŵp Newyddion.
+MissingRecipientEncryptionCert=Rydych wedi pennu amgryptiad ar gyfer y neges, ond methodd y rhaglen â chanfod tystysgrif amgryptio ar gyfer %S.
+ErrorEncryptMail=Methu amgryptio'r neges. Gwiriwch fod gennych dystysgrif e-bost dilys ar gyfer pob derbynnydd. Gwiriwch fod y tystysgrifau enwyd yn Gosodiadau Cyfrifon E-bost a Grwpiau Newyddion ar gyfer y cyfrif e-bost yn ddilys a dibynadwy ar gyfer e-bost.
+ErrorCanNotSignMail=Methu llofnodi'r neges. Gwiriwch fod y tystysgrifau enwyd yn Gosodiadau Cyfrifon E-bost a Grwpiau Newyddion ar gyfer y cyfrif e-bost yn ddilys a dibynadwy ar gyfer e-bost.
+
+NoSigningCert=Nid yw'r Rheolwr Tystysgrifau wedi gallu canfod tystysgrif ddilys i'w ddefnyddio i lofnodi eich negeseuon.
+NoSigningCertForThisAddress=Nid yw'r Rheolwr Tystysgrifau wedi gallu canfod tystysgrif ddilys i'w ddefnyddio i lofnodi eich negeseuon gyda cyfeiriad <%S>.
+NoEncryptionCert=Nid yw'r Rheolwr Tystysgrifau wedi gallu canfod tystysgrif ddilys i bobl eraill ddefnyddio i anfon negeseuon e-bost wedi'u hamgryptio.
+NoEncryptionCertForThisAddress=Nid yw'r Rheolwr Tystysgrifau wedi gallu canfod tystysgrif ddilys i bobl eraill ddefnyddio i anfon negeseuon e-bost wedi'u hamgryptio i'r cyfeiriad <%S>.
+
+encryption_needCertWantSame=Dylech hefyd bennu tystysgrif ar gyfer pobl eraill i'w defnyddio pan fyddant yn anfon negeseuon wedi'u hamgryptio atoch. Hoffech chi ddefnyddio'r un dystysgrif i amgryptio a dadgriptio negeseuon anfonwyd atoch?
+encryption_wantSame=Ydych chi am ddefnyddio'r un dystysgrif i amgryptio a dadgriptio negeseuon anfonwyd atoch?
+encryption_needCertWantToSelect=Dylech bennu tystysgrif ar gyfer pobl eraill pan fyddwch yn anfon neges wedi'i hamgryptio atoch. Hoffech chi ffurfweddu tystysgrif amgryptio?
+signing_needCertWantSame=Dylech hefyd bennu tystysgrif i'w defnyddio ar gyfer llofnodi eich negeseuon yn ddigidol. Hoffech chi ddefnyddio'r un dystysgrif i lofnodi eich negeseuon yn ddigidol?
+signing_wantSame=Hoffech chi ddefnyddio'r un dystysgrif i lofnodi eich negeseuon yn ddigidol?
+signing_needCertWantToSelect=Dylech hefyd bennu tystysgrif i'w ddefnyddio ar gyfer llofnodi eich negeseuon yn ddigidol. Hoffech chi ffurfweddu tystysgrif ar gyfer llofnodi negeseuon yn ddigidol?
+
+## Strings used by nsMsgComposeSecure
+mime_smimeEncryptedContentDesc=Neges Amgryptiedig S/MIME
+mime_smimeSignatureContentDesc=Llofnod Cryptograffeg S/MIME
+
+## Strings used by the cert picker.
+CertInfoIssuedFor=Cyhoeddwyd i:
+CertInfoIssuedBy=Cyhoeddwyd gan:
+CertInfoValid=Dilys
+CertInfoFrom=oddi wrth
+CertInfoTo=at
+CertInfoPurposes=Pwrpas
+CertInfoEmail=E-bost
+CertInfoStoredIn=Storiwyd yn:
+NicknameExpired=(daeth i ben)
+NicknameNotYetValid=(nid yn ddilys eto)
diff --git a/l10n-cy/mail/chrome/messenger/app-extension-fields.properties b/l10n-cy/mail/chrome/messenger/app-extension-fields.properties
new file mode 100644
index 0000000000..58cb6ee40f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/app-extension-fields.properties
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (extension.thunderbird-compact-light@mozilla.org.name): This is displayed in about:addons -> Appearance
+extension.thunderbird-compact-light@mozilla.org.name=Golau
+extension.thunderbird-compact-light@mozilla.org.description=Thema gyda chynllun lliw golau.
+
+# LOCALIZATION NOTE (extension.thunderbird-compact-dark@mozilla.org.name): This is displayed in about:addons -> Appearance
+extension.thunderbird-compact-dark@mozilla.org.name=Tywyll
+extension.thunderbird-compact-dark@mozilla.org.description=Thema sydd â chynllun lliw tywyll.
diff --git a/l10n-cy/mail/chrome/messenger/appUpdate.properties b/l10n-cy/mail/chrome/messenger/appUpdate.properties
new file mode 100644
index 0000000000..ca3d623504
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/appUpdate.properties
@@ -0,0 +1,40 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (updateAvailableTitle): %S will be replaced with brandShortName
+updateAvailableTitle=Mae diweddariad %S newydd ar gael.
+# LOCALIZATION NOTE (updateAvailableMessage): %S will be replaced with brandShortName
+updateAvailableMessage=Diweddarwch eich %S am y cyflymder a'r preifatrwydd diweddaraf.
+updateAvailablePrimaryButtonLabel=Llwytho'r Diweddariad i Lawr
+updateAvailablePrimaryButtonAccessKey=D
+updateAvailableSecondaryButtonLabel=Nid Nawr
+updateAvailableSecondaryButtonAccessKey=N
+
+# LOCALIZATION NOTE (updateManualTitle): %S will be replaced with brandShortName
+updateManualTitle=Nid yw %S yn gallu diweddaru i'r fersiwn diweddaraf.
+# LOCALIZATION NOTE (updateManualMessage): %S will be replaced with brandShortName
+updateManualMessage=Llwythwch gopi newydd o %S i lawr ac mi wnawn ni eich helpu i'w gosod.
+# LOCALIZATION NOTE (updateManualPrimaryButtonLabel): %S will be replaced with brandShortName
+updateManualPrimaryButtonLabel=Llwytho i Lawr %S
+updateManualPrimaryButtonAccessKey=L
+updateManualSecondaryButtonLabel=Nid Nawr
+updateManualSecondaryButtonAccessKey=N
+
+# LOCALIZATION NOTE (updateUnsupportedTitle): %S will be replaced with brandShortName
+updateUnsupportedTitle=Nid yw %S yn gallu diweddaru i'r fersiwn diweddaraf.
+# LOCALIZATION NOTE (updateUnsupportedMessage): %S will be replaced with brandShortName
+updateUnsupportedMessage=Nid yw'r fersiwn diweddaraf o %S yn cael ei gynnal gan eich system.
+updateUnsupportedPrimaryButtonLabel=Dysgu rhagor
+updateUnsupportedPrimaryButtonAccessKey=D
+updateUnsupportedSecondaryButtonLabel=Cau
+updateUnsupportedSecondaryButtonAccessKey=C
+
+# LOCALIZATION NOTE (updateRestartTitle): %S will be replaced with brandShortName
+updateRestartTitle=Ailgychwyn i ddiweddaru %S.
+# LOCALIZATION NOTE (updateRestartMessage): %S will be replaced with brandShortName
+updateRestartMessage=Ar ôl ail gychwyn cyflym, bydd %S yn adfer eich holl dabiau a'r ffenestri sydd ar agor.
+updateRestartPrimaryButtonLabel=Ail gychwyn
+updateRestartPrimaryButtonAccessKey=A
+updateRestartSecondaryButtonLabel=Nid Nawr
+updateRestartSecondaryButtonAccessKey=N
diff --git a/l10n-cy/mail/chrome/messenger/appleMailImportMsgs.properties b/l10n-cy/mail/chrome/messenger/appleMailImportMsgs.properties
new file mode 100644
index 0000000000..b47b5aaed7
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/appleMailImportMsgs.properties
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Short name of import module
+ApplemailImportName=Apple Mail
+
+# Description of import module
+ApplemailImportDescription=Mewnforio E-bost Lleol o Mac OS X Mail
+
+# Success Message
+# LOCALIZATION NOTE(ApplemailImportMailboxSuccess): Do not translate the word "%S" below.
+ApplemailImportMailboxSuccess=Mewnforiwyd negeseuon lleol yn llwyddiannus o %S
+
+# Error Message
+ApplemailImportMailboxBadparam=Digwyddodd gwall mewnol. Methodd mewnforio. Ceisiwch fewnforio eto.
+
+# Error message
+# LOCALIZATION NOTE(ApplemailImportMailboxConverterror): Do not translate the word "%S" below.
+ApplemailImportMailboxConverterror=Digwyddodd gwall wrth fewnforio negeseuon o %S. Nid yw'r negeseuon wedi'u mewnforio.
+
diff --git a/l10n-cy/mail/chrome/messenger/baseMenuOverlay.dtd b/l10n-cy/mail/chrome/messenger/baseMenuOverlay.dtd
new file mode 100644
index 0000000000..2d901b19a1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/baseMenuOverlay.dtd
@@ -0,0 +1,40 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Help Menu -->
+<!ENTITY helpMenu.label "Cymorth">
+<!ENTITY helpMenu.accesskey "C">
+<!-- LOCALIZATION NOTE some localizations of Windows use "?"
+                       for the help button in the menubar but Gnome does not.   -->
+<!ENTITY helpMenuWin.label "Cymorth">
+<!ENTITY helpMenuWin.accesskey "y">
+<!ENTITY aboutProduct2.label "Ynghylch &brandShorterName;">
+<!ENTITY aboutProduct2.accesskey "Y">
+<!ENTITY helpTroubleshootingInfo.label     "Gwybodaeth am Ddatrys Problemau">
+<!ENTITY helpTroubleshootingInfo.accesskey "G">
+<!ENTITY helpSafeMode.label     "Ailgychwyn gydag Ychwanegion wedi'u Hanalluogi…">
+<!ENTITY helpSafeMode.accesskey "A">
+
+<!ENTITY helpSafeMode.stop.label     "Ailgychwyn gydag Ychwanegion wedi eu Galluogi">
+<!ENTITY helpSafeMode.stop.accesskey "A">
+<!ENTITY productHelp.label "Cymorth &brandShortName;">
+<!ENTITY productHelp.accesskey "C">
+<!ENTITY productHelp.commandkey "VK_F1">
+<!ENTITY productHelpMac.commandkey "?">
+<!ENTITY productHelpMac.modifiers "accel">
+
+<!ENTITY helpKeyboardShortcuts.label "Llwybrau Byr Bysellfwrdd">
+<!ENTITY helpKeyboardShortcuts.accesskey "L">
+
+<!ENTITY helpFeedbackPage.label "Cyflwyno Adborth…">
+<!ENTITY helpFeedbackPage.accesskey "A">
+
+<!ENTITY helpShowTour2.label "Cyflwyno &brandShorterName;">
+<!ENTITY helpShowTour2.accesskey "C">
+
+<!ENTITY helpGetInvolvedPage.label "Ymunwch">
+<!ENTITY helpGetInvolvedPage.accesskey "Y">
+
+<!ENTITY helpDonationsPage.label "Gwnewch Rodd">
+<!ENTITY helpDonationsPage.accesskey "R">
diff --git a/l10n-cy/mail/chrome/messenger/beckyImportMsgs.properties b/l10n-cy/mail/chrome/messenger/beckyImportMsgs.properties
new file mode 100644
index 0000000000..4c22395c01
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/beckyImportMsgs.properties
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# The following are used by the becky import code to display status/error
+# and informational messages
+
+# Short name of import module
+BeckyImportName=Becky! Internet Mail
+
+# Description of import module
+BeckyImportDescription=Mewnforion E-byst Lleol o Becky! Internet Mail
+
+# Success Message
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+# The variable %S will contain the name of the Mailbox
+BeckyImportMailboxSuccess=Mewnforiwyd negeseuon lleol yn llwyddiannus o %S.
+
+BeckyImportAddressSuccess=Mewnforiwyd y llyfr cyfeiriadau
diff --git a/l10n-cy/mail/chrome/messenger/charsetTitles.properties b/l10n-cy/mail/chrome/messenger/charsetTitles.properties
new file mode 100644
index 0000000000..d5d60eda3d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/charsetTitles.properties
@@ -0,0 +1,84 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+## Rule of this file:
+## 1. key should always be in lower case ascii so we can do case insensitive
+##    comparison in the code faster.
+
+## Format of this file:
+## charset_name.title = a_title  -  specifies the human readable title for 
+## this charset
+
+## Format of this file:
+## charset_name.title = a_title  -  specifies the human readable title for
+## this charset
+
+iso-8859-1.title    = Gorllewinol (ISO-8859-1)
+iso-8859-2.title    = Canol Ewrop (ISO-8859-2)
+iso-8859-3.title    = De Ewropeaidd (ISO-8859-3)
+iso-8859-4.title    = Baltig (ISO-8859-4)
+iso-8859-10.title   = Nordaidd (ISO-8859-10)
+iso-8859-13.title   = Baltig (ISO-8859-13)
+iso-8859-14.title   = Celtaidd (ISO-8859-14)
+iso-8859-15.title   = Gorllewinol (ISO-8859-15)
+iso-8859-16.title   = Rwmaneg (ISO-8859-16)
+windows-1250.title  = Canol Ewrop (Windows-1250)
+windows-1252.title  = Gorllewinol (Windows-1252)
+windows-1254.title  = Twrceg (Windows-1254)
+windows-1257.title  = Baltig (Windows-1257)
+macintosh.title         = Gorllewinol (MacRoman)
+x-mac-ce.title          = Canol Ewrop (MacCE)
+x-mac-turkish.title     = Twrceg (MacTurkish)
+x-mac-croatian.title    = Croateg (MacCroatian)
+x-mac-romanian.title    = Rwmanaidd (MacRomanian)
+x-mac-icelandic.title   = Islandeg (MacIcelandic)
+iso-2022-jp.title = Japanëeg (ISO-2022-JP)
+shift_jis.title = Japanëeg (Shift-JIS)
+euc-jp.title = Japanëeg (EUC-JP)
+big5.title = Tsieinëeg Traddodiadol (Big5)
+big5-hkscs.title = Tsieinëeg Traddodiadol (Big5-HK_SCS)
+gb2312.title = Tsieinëeg Symledig (GB2312)
+gbk.title = Tsieinëeg Symledig (GBK)
+euc-kr.title = Corëeg (EUC-KR)
+utf-7.title = Unicode (UTF-7)
+utf-8.title = Unicode (UTF-8)
+utf-16.title = Unicode (UTF-16)
+utf-16le.title = Unicode (UTF-16LE)
+utf-16be.title = Unicode (UTF-16BE)
+iso-8859-5.title = Cyrilig (ISO-8859-5)
+windows-1251.title = Syrilig (Windows-1251)
+x-mac-cyrillic.title = Cyrilig (MacCyrillic)
+x-mac-ukrainian.title = Cyrilig/Wcraneg(MacUkrainian)
+koi8-r.title = Cyrilig (KOI8-R)
+koi8-u.title = Cyrilig/Wcraneg (KOI8-U)
+iso-8859-7.title = Groeg (ISO-8859-7)
+windows-1253.title = Groeg (Windows-1253)
+x-mac-greek.title = Groeg (MacGreek)
+windows-1258.title = Fietnameg (Windows-1258)
+windows-874.title = Thai (Windows-874)
+iso-8859-6.title = Arabeg (ISO-8859-6)
+iso-8859-8.title = Hebraeg Gweledol (ISO-8859-8)
+iso-8859-8-i.title = Hebraeg (ISO-8859-8-I)
+windows-1255.title = Hebraeg (Windows-1255)
+windows-1256.title = Arabeg (Windows-1256)
+x-user-defined.title = Defnyddiwr Diffiniedig
+ibm866.title = Cyrillig/Rwsia (CP-866)
+gb18030.title = Tsieinëeg Symliedig (_GB18030)
+x-mac-arabic.title = Arabeg (MacArabic)
+x-mac-farsi.title = Ffarsi (MacFarsi)
+x-mac-hebrew.title = Hebraeg (MacHebrew)
+x-mac-devanagari.title = Hindi (MacDevanagari)
+x-mac-gujarati.title = Gujurati (MacGujurati)
+x-mac-gurmukhi.title = Gurmukhi (MacGurmukhi)
+
+chardet.off.title                           = (Diffodd)
+chardet.universal_charset_detector.title    = Cyffredinol
+chardet.ja_parallel_state_machine.title     = Siapanëeg
+chardet.ko_parallel_state_machine.title     = Corëeg
+chardet.zhtw_parallel_state_machine.title   = Tsieinëeg Traddodiadol
+chardet.zhcn_parallel_state_machine.title   = Tsieinëeg Syml
+chardet.zh_parallel_state_machine.title     = Tseinëeg
+chardet.cjk_parallel_state_machine.title    = Dwyrain Asia
+chardet.ruprob.title                        = Rwsiaidd
+chardet.ukprob.title                        = Wcranaidd
diff --git a/l10n-cy/mail/chrome/messenger/chat.dtd b/l10n-cy/mail/chrome/messenger/chat.dtd
new file mode 100644
index 0000000000..24d534cd34
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/chat.dtd
@@ -0,0 +1,44 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY onlineContactsHeader.label    "Cysylltiadau Ar-lein">
+<!ENTITY offlineContactsHeader.label   "Cysylltiadau All-lein">
+<!ENTITY conversationsHeader.label     "Sgyrsiau">
+<!ENTITY searchResultConversation.label "Canlyniadau chwilio">
+<!ENTITY chat.noConv.title             "Bydd trafodaethau'n cael eu dangos yn fan hyn.">
+<!ENTITY chat.noConv.description       "Defnyddiwch y rhestr cysylltiadau yn y panel ar y chwith er mwyn cychwyn trafodaeth.">
+<!ENTITY chat.noPreviousConv.description       "Nid oes gan &brandShortName; unrhyw drafodaethau blaenorol wedi eu cadw gyda'r cysylltiad yma.">
+<!ENTITY chat.noAccount.title             "Nid ydych wedi creu cyfrif sgwrsio eto.">
+<!ENTITY chat.noAccount.description       "Gadewch i &brandShortName; eich tywys drwy'r broses o greu cyfrif sgwrsio.">
+<!ENTITY chat.accountWizard.button       "Cychwyn arni">
+<!ENTITY chat.noConnectedAccount.title             "Nid yw eich cyfrifon sgwrsio wedi'u cysylltu.">
+<!ENTITY chat.noConnectedAccount.description       "Mae modd eu cysylltu drwy'r ddeialog 'Statws sgwrsio':">
+<!ENTITY chat.showAccountManager.button       "Dangos statws sgwrsio">
+
+<!ENTITY chat.participants             "Cyfranogwyr:">
+<!ENTITY chat.previousConversations    "Sgyrsiau Blaenorol:">
+<!ENTITY chat.ongoingConversation      "Sgwrs gyfredol">
+
+<!ENTITY openConversationCmd.label     "Cychwyn Sgwrs">
+<!ENTITY openConversationCmd.accesskey "C">
+<!ENTITY closeConversationCmd.label    "Gorffen Sgwrs">
+<!ENTITY closeConversationCmd.accesskey "G">
+<!ENTITY aliasCmd.label                "Ailenwi">
+<!ENTITY aliasCmd.accesskey            "A">
+<!ENTITY deleteCmd.label               "Tynnu Cysylltiad">
+<!ENTITY deleteCmd.accesskey           "T">
+
+<!ENTITY openConversationButton.tooltip  "Cychwyn trafodaeth">
+<!ENTITY closeConversationButton.tooltip "Gorffen trafodaeth">
+
+<!ENTITY addBuddyButton.label          "Ychwanegu Cysylltiad">
+<!ENTITY joinChatButton.label          "Ymuno â Sgwrs">
+<!ENTITY chatAccountsButton.label      "Dangos Cyfrifon">
+
+<!ENTITY status.available          "Ar Gael">
+<!ENTITY status.unavailable        "Ddim ar Gael">
+<!ENTITY status.offline            "All-lein">
+
+<!ENTITY openLinkCmd.label            "Agor Dolen…">
+<!ENTITY openLinkCmd.accesskey        "D">
diff --git a/l10n-cy/mail/chrome/messenger/chat.properties b/l10n-cy/mail/chrome/messenger/chat.properties
new file mode 100644
index 0000000000..c3ac63b42e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/chat.properties
@@ -0,0 +1,99 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+chatTabTitle=Sgwrsio
+goBackToCurrentConversation.button=Nôl i'r drafodaeth gyfredol
+# LOCALIZATION NOTE (startAConversationWith.button):
+#  %S is replaced with the display name of a contact.
+startAConversationWith.button=Cychwyn trafodaeth gyda %S
+
+# LOCALIZATION NOTE (defaultGroup):
+#  this is used in the addBuddies dialog if the list of existing groups is empty
+defaultGroup=Cysylltiadau
+
+# LOCALIZATION NOTE (buddy.authRequest.label):
+# This string appears in a notification bar at the
+# top of the Contacts window when someone added the user to his/her
+# contact list, to request the permission from the user to share
+# status information with this potential new contact.
+# %S is replaced with the user name of the potential new contact.
+buddy.authRequest.label=Mae %S eisiau sgwrsio gyda chi
+buddy.authRequest.allow.label=Caniatáu
+buddy.authRequest.allow.accesskey=C
+buddy.authRequest.deny.label=Gwrthod
+buddy.authRequest.deny.accesskey=G
+
+# LOCALIZATION NOTE (buddy.deletePrompt.title):
+# %S here will be replaced by the alias (or username) of a buddy about
+# to be removed from the buddy list.
+buddy.deletePrompt.title=Dileu %S?
+
+# LOCALIZATION NOTE (buddy.deletePrompt.message):
+# %1$S will be replaced by the name of a buddy (either the alias
+# followed by the username between parenthesis if an alias is set, or
+# only the username otherwise).
+# %2$S will be the name of the protocol on which this buddy is removed
+# (for example: AIM, MSN, Google Talk).
+#
+# Please find a wording that will keep the username as close as
+# possible to the beginning of the string, because this is the
+# important information that an user should see when looking quickly
+# at this prompt.
+buddy.deletePrompt.message=Bydd %1$S yn cael ei dynnu'n barhaol o'ch rhestr ffrindiau %2$S os byddwch yn parhau.
+
+# LOCALIZATION NOTE (buddy.deletePrompt.displayName):
+# This is used to format the display name inserted in buddy.deletePrompt.message
+# %1$S is the alias, %2$S is the username.
+buddy.deletePrompt.displayName=%1$S (%2$S)
+
+# LOCALIZATION NOTE (buddy.deletePrompt.button):
+# the & symbol indicates the position of the character that should be
+# used as the accesskey for this button.
+buddy.deletePrompt.button=&Dileu
+
+displayNameEmptyText=Dangos Enw
+userIconFilePickerTitle=Dewis eicon newydd…
+
+# LOCALIZATION NOTE (chat.isTyping, chat.hasStoppedTyping):
+# The contact display name is displayed with a big font on a first
+# line and these two strings are displayed on a second line with a
+# smaller font. Please try to find a wording that make this look
+# almost like a sentence.
+chat.isTyping=yn teipio…
+chat.hasStoppedTyping=wedi stopio teipio.
+# LOCALIZATION NOTE (chat.contactIsTyping, chat.contactHasStoppedTyping):
+#  These strings are displayed in a tooltip when hovering the status type icon.
+#  %S is replaced with the display name of the contact.
+chat.contactIsTyping=Mae %S yn teipio.
+chat.contactHasStoppedTyping=Mae %S wedi stopio teipio.
+
+# LOCALIZATION NOTE (unknownCommand):
+# This is shown when an unknown command (/foo) is attempted. %S is the command.
+unknownCommand=Nid yw %S yn orchymyn sy'n cael ei chynnal. Teipiwch /help i weld y rhestr o orchmynion.
+
+#LOCALIZATION NOTE
+# These are special entries in the log tree for the corresponding days.
+log.today=Heddiw
+log.yesterday=Ddoe
+
+#LOCALIZATION NOTE
+# These are special groups in the log tree for the last 3-7 days and
+# the last 8-14 days.
+log.currentWeek=Wythnos hon
+log.previousWeek=Wythnos Diwethaf
+
+# LOCALIZATION NOTE (messagePreview):
+# This is the default message preview to be shown
+# when the user has chosen not to show any info in the notification about the
+# incoming message being notified.
+messagePreview=Neges Sgwrs Newydd
+
+#LOCALIZATION NOTE (bundledMessagePreview):  Semi-colon list of plural forms.
+# Used when multiple incoming messages from the same sender are bundled
+# into a single notification.
+# #1 is the number of incoming messages the user is being notified about. When #1
+# is greater than one, the plural form after the semicolon is used.
+# Do not translate %1$S, it is the message preview to be shown in the
+# notification, i.e. the first incoming message.
+bundledMessagePreview=%1$S… (a #1 neges ychwanegol);%1$S… (a #1 neges ychwanegol)
diff --git a/l10n-cy/mail/chrome/messenger/configEditorOverlay.dtd b/l10n-cy/mail/chrome/messenger/configEditorOverlay.dtd
new file mode 100644
index 0000000000..3d78799d68
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/configEditorOverlay.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY closeCmd.key "W">
diff --git a/l10n-cy/mail/chrome/messenger/converterDialog.dtd b/l10n-cy/mail/chrome/messenger/converterDialog.dtd
new file mode 100644
index 0000000000..9ea79f5311
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/converterDialog.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY converterDialog.title "Troswr Math Cadw Neges">
+<!ENTITY converterDialog.continueButton "Ymlaen">
+<!ENTITY converterDialog.cancelButton "Diddymu">
+<!ENTITY converterDialog.finishButton "Gorffen">
+<!ENTITY converterDialog.complete "Mae'r trosi wedi ei gwblhau. Bydd &brandShortName; nawr yn ail gychwyn.">
+<!ENTITY converterDialog.error "Methodd y trosi.">
+
diff --git a/l10n-cy/mail/chrome/messenger/converterDialog.properties b/l10n-cy/mail/chrome/messenger/converterDialog.properties
new file mode 100644
index 0000000000..9bba0f3c62
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/converterDialog.properties
@@ -0,0 +1,41 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (converterDialog.warning):
+# %1$S will be replaced by the name of the account which is going to be converted.
+# %2$S will be replaced by the format into which the account will be converted.
+# %3$S will be replaced by $BrandShortName.
+converterDialog.warning=Bydd y negeseuon yng nghyfrif %1$S nawr yn cael eu trosi i fformat %2$S. Bydd %3$S yn ailgychwyn wedi i'r trosi gael ei gwblhau.
+
+# LOCALIZATION NOTE (converterDialog.message):
+# %1$S will be replaced by the name of the account which is being converted.
+# %2$S will be replaced by the format into which the account will be converted.
+converterDialog.message=Trosi cyfrif %1$S i %2$S…
+
+# LOCALIZATION NOTE (converterDialog.warningForDeferredAccount):
+# %1$S will be replaced by the name of the deferred account for which migration is initiated by the user.
+# %2$S will be replaced by the name of the account to which the deferred account is deferred ie the name of the deferred-to account.
+# %3$S will be replaced by the name of the deferred-to account.
+# %4$S will be replaced by a comma separated list of names of accounts which are deferred to the deferred-to account.
+# %5$S will be replaced by a comma separated list of names of accounts which are going to get converted.
+# %6$S will be replaced by the format into which the accounts will be converted.
+# %7$S will be replaced by $BrandShortName.
+converterDialog.warningForDeferredAccount=Mae %1$S wedi ei drosi i %2$S. Cyfrifon wedi eu trosi i %3$S: %4$S. Bydd y negeseuon yn nghyfrifon %5$S yn cael eu trosi i fformat %6$S. Bydd %7$S yn ailgychwyn wedi i'r trosi gael ei gwblhau.
+
+# LOCALIZATION NOTE (converterDialog.warningForDeferredToAccount):
+# %1$S will be replaced by the name of the deferred-to account for which migration is initiated by the user and to which other accounts are deferred.
+# %2$S will be replaced by a comma separated list of names of accounts which are deferred to the deferred-to account.
+# %3$S will be replaced by a comma separated list of names of accounts which are going to get converted.
+# %4$S will be replaced by the format into which the accounts will be converted.
+# %5$S will be replaced by $BrandShortName.
+converterDialog.warningForDeferredToAccount=Cyfrifon wedi eu trosi i %1$S: %2$S. Bydd y negeseuon yng nghyfrif %3$S nawr yn cael eu trosi i fformat %4$S. Bydd %5$S yn ailgychwyn wedi i'r trosi gael ei gwblhau.
+
+# LOCALIZATION NOTE (converterDialog.messageForDeferredAccount):
+# %1$S will be replaced by a comma separated list of names of accounts which are being converted.
+# %2$S will be replaced by the format into which the accounts will be converted.
+converterDialog.messageForDeferredAccount=Trosi cyfrifon %1$S i %2$S…
+
+# LOCALIZATION NOTE (converterDialog.percentDone):
+# %1$S will be replaced by the percentage of conversion that is complete.
+converterDialog.percentDone=%1$S%% wedi ei gwblhau
diff --git a/l10n-cy/mail/chrome/messenger/custom.properties b/l10n-cy/mail/chrome/messenger/custom.properties
new file mode 100644
index 0000000000..d4ca87a701
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/custom.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+colonInHeaderName=Mae'r pennyn rydych wedi ei roi yn cynnwys nodau annilys, megis ':', nod anargraffadwy, nod nad yw'n ascii, neu nod ascii wyth did. Tynnwch y nod annilys a cheisiwch eto.
diff --git a/l10n-cy/mail/chrome/messenger/customizeToolbar.dtd b/l10n-cy/mail/chrome/messenger/customizeToolbar.dtd
new file mode 100644
index 0000000000..7a5e7dc048
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/customizeToolbar.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY dialog.title             "Cyfaddasu'r Bar Offer">
+<!ENTITY dialog.dimensions        "width: 92ch; height: 36em;">
+<!ENTITY instructions.description "Gallwch ychwanegu neu dynnu eitemau drwy lusgo i neu oddi wrth y barau offer.">
+<!ENTITY show.label               "Dangos:">
+<!ENTITY iconsAndText.label       "Eiconau a Thestun">
+<!ENTITY icons.label              "Eiconau">
+<!ENTITY text.label               "Testun">
+<!ENTITY iconsBesideText.label    "Eiconau gerllaw Testun">
+<!ENTITY useSmallIcons.label      "Defnyddio Eiconau Bach">
+<!ENTITY restoreDefaultSet.label  "Adfer y Set Ragosodedig">
+<!ENTITY showTitlebar2.label      "Bar Teitl">
+<!ENTITY extraDragSpace2.label    "Gofod Llusgo">
+<!ENTITY saveChanges.label        "Gorffen">
+<!ENTITY undoChanges.label        "Dadwneud Newidiadau">
diff --git a/l10n-cy/mail/chrome/messenger/customizeToolbar.properties b/l10n-cy/mail/chrome/messenger/customizeToolbar.properties
new file mode 100644
index 0000000000..3b1e6eafed
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/customizeToolbar.properties
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+enterToolbarTitle=Bar Offer Newydd
+enterToolbarName=Rhoi enw i'r bar offer hwn:
+enterToolbarDup=Mae eisoes far offer gyda'r enw “%S”. Rhowch enw arall.
+enterToolbarBlank=Rhaid cynnig enw i greu bar offer newydd.
+separatorTitle=Ymwahanydd
+springTitle=Bwlch Hyblyg
+spacerTitle=Bwlch
diff --git a/l10n-cy/mail/chrome/messenger/devtools/dbgserver.dtd b/l10n-cy/mail/chrome/messenger/devtools/dbgserver.dtd
new file mode 100644
index 0000000000..04bd420531
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/devtools/dbgserver.dtd
@@ -0,0 +1,4 @@
+<!ENTITY options.title "Dewisiadau Offer Datblygwyr">
+<!ENTITY options.status.label "Statws:">
+<!ENTITY options.port.label "Porth:">
+<!ENTITY options.forcelocal.label "Caniatáu cysylltiadau o gyfrifiaduron eraill">
diff --git a/l10n-cy/mail/chrome/messenger/devtools/dbgserver.properties b/l10n-cy/mail/chrome/messenger/devtools/dbgserver.properties
new file mode 100644
index 0000000000..fa0ad49e26
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/devtools/dbgserver.properties
@@ -0,0 +1,11 @@
+options.stop.label=Atal y Gweinydd Offer Datblygwyr
+options.start.label=Cychwyn y Gweinydd Offer Datblygwyr
+
+options.connected.label=#1 Client wedi'i Gysylltu;#1 Client wedi eu Cysylltu
+options.connected.tooltip=Mae gweinydd offer datblygwyr yn rhedeg ac mae cleientiaid wedi eu cysylltu.
+options.listening.label=Gwrando
+options.listening.tooltip=Mae'r gweinydd offer datblygwyr yn rhedeg ac yn aros am gysylltiadau.
+options.idle.label=Ddim yn Rhedeg
+options.idle.tooltip=Nid yw'r gweinydd offer datblygwyr yn rhedeg. Mae modd ei gychwyn o fan hyn.
+options.unsupported.label=Heb ei gynnal
+options.unsupported.tooltip=Bu gwall llwytho'r gweinydd datblygwr mewnol. Gwenwch yn siŵr ei fod wedi ei becynnu a gwiriwch eich consol gwall am negeseuon.
diff --git a/l10n-cy/mail/chrome/messenger/downloadheaders.dtd b/l10n-cy/mail/chrome/messenger/downloadheaders.dtd
new file mode 100644
index 0000000000..88e3ddc178
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/downloadheaders.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY all.label          "Llwytho pob pennyn i lawr">
+<!ENTITY all.accesskey      "p">
+<!--LOCALIZATION NOTE (download.label):
+    consider the download.label and headers.label as a single sentence
+   with the number of headers to be downloaded inserted between them:
+   EXAMPLE: "Download" <some number> "headers"
+   Either label could be set to null ("") if required grammatically.
+-->
+
+<!--LOCALIZATION NOTE (download.label):
+    consider the download.label and headers.label as a single sentence
+    with the number of headers to be downloaded inserted between them:
+    EXAMPLE: "Download" <some number> "headers"
+    Either label could be set to null ("") if required grammatically.
+-->
+
+<!ENTITY download.label     "Llwytho i Lawr">
+<!ENTITY download.accesskey "L">
+<!--LOCALIZATION NOTE (headers.label): see note for download.label -->
+<!ENTITY headers.label      "penynnau">
+<!ENTITY headers.accesskey  "p">
+<!ENTITY mark.label         "Marcio gweddill y penynnau fel wedi darllen">
+<!ENTITY mark.accesskey     "M">
diff --git a/l10n-cy/mail/chrome/messenger/editContactOverlay.dtd b/l10n-cy/mail/chrome/messenger/editContactOverlay.dtd
new file mode 100644
index 0000000000..d8dff07314
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/editContactOverlay.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY editContactPanelDeleteContact.label "Dileu">
+<!ENTITY editContactPanelDeleteContact.accesskey "D">
+
+<!ENTITY editContactName.label "Enw:">
+<!ENTITY editContactName.accesskey "E">
+
+<!ENTITY editContactEmail.label "E-bost:">
+<!ENTITY editContactEmail.accesskey "b">
+
+<!ENTITY editContactAddressBook.label "Llyfr Cyfeiriadau:">
+<!ENTITY editContactAddressBook.accesskey "L">
+
+<!ENTITY editContactPanelDone.label "Gorffen">
+<!ENTITY editContactPanelDone.accesskey "G">
+
+<!ENTITY contactMoveDisabledWarning.description "Nid oes modd newid y llyfr cyfeiriadau gan fod y cysylltiad mewn rhestr e-bostio.">
diff --git a/l10n-cy/mail/chrome/messenger/editContactOverlay.properties b/l10n-cy/mail/chrome/messenger/editContactOverlay.properties
new file mode 100644
index 0000000000..f2a19d2916
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/editContactOverlay.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+editTitle=Golygu Cysylltiad
+viewTitle=Gweld Cysylltiad
+
+editDetailsLabel=Golygu Manylion
+editDetailsAccessKey=M
+viewDetailsLabel=Gweld Manylion
+viewDetailsAccessKey=G
+
+deleteContactTitle=Dileu Cysylltiad
+deleteContactMessage=Ydych chi'n siŵr eich bod eisiau dileu'r Cysylltiad?
diff --git a/l10n-cy/mail/chrome/messenger/fieldMapImport.dtd b/l10n-cy/mail/chrome/messenger/fieldMapImport.dtd
new file mode 100644
index 0000000000..5a996218e1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/fieldMapImport.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY fieldMapImport.title "Mewnforio Llyfr Cyfeiriadau">
+<!ENTITY fieldMapImport.size "width: 40em; height: 30em;">
+<!ENTITY fieldMapImport.recordNumber "Data wedi'i fewnforio ar gyfer Cofnod: ">
+<!ENTITY fieldMapImport.next.label "Nesaf">
+<!ENTITY fieldMapImport.next.accesskey "N">
+<!ENTITY fieldMapImport.previous.label "Blaenorol">
+<!ENTITY fieldMapImport.previous.accesskey "B">
+<!ENTITY fieldMapImport.text "Defnyddiwch Symud i Fyny a Symud i Lawr i gydweddu meysydd y llyfr cyfeiriadau ar y chwith gyda'r data cywir i'w fewnforio ar y dde. Dad-diciwch eitemau nad ydych am eu mewnforio.">
+<!ENTITY fieldMapImport.up.label "Symud i Fyny">
+<!ENTITY fieldMapImport.up.accesskey "F">
+<!ENTITY fieldMapImport.down.label "Symud i Lawr">
+<!ENTITY fieldMapImport.down.accesskey "L">
+<!ENTITY fieldMapImport.fieldListTitle "Meysydd Llyfr Cyfeiriadau">
+<!ENTITY fieldMapImport.dataTitle "Cofnodi data i'w fewnforio">
+<!ENTITY fieldMapImport.skipFirstRecord.label "Mae'r cofnod cyntaf yn cynnwys enwau meysydd">
+<!ENTITY fieldMapImport.skipFirstRecord.accessKey "c">
diff --git a/l10n-cy/mail/chrome/messenger/filter.properties b/l10n-cy/mail/chrome/messenger/filter.properties
new file mode 100644
index 0000000000..803f94573f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/filter.properties
@@ -0,0 +1,110 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+mustSelectFolder=Rhaid dewis ffolder targed.
+enterValidEmailAddress=Rhowch gyfeiriad e-bost dilys i'w anfon ymlaen.
+pickTemplateToReplyWith=Dewiswch dempled i ymateb.
+mustEnterName=Rhaid rhoi enw i'r hidl.
+cannotHaveDuplicateFilterTitle=Dyblygu Enw'r Hidl
+cannotHaveDuplicateFilterMessage=Mae'r enw hidl rydych wedi'i roi yn bodoli eisoes. Rhowch enw hidl gwahanol.
+mustHaveFilterTypeTitle=Heb ddewis hidl digwyddiad
+mustHaveFilterTypeMessage=Rhaid dewis o leiaf un digwyddiad pan mae'r hidl yn cael ei osod. Os nad ydych am i'r hidl redeg dros dro ar gyfer unrhyw ddigwyddiad, dad-diciwch ei gyflwr gweithredol yn y deialog Hidlau Negeseuon.
+deleteFilterConfirmation=Ydych chi'n siŵr eich bod eisiau dileu'r hidl(au)?
+untitledFilterName=Hidl Heb Deitl
+matchAllFilterName=Cydweddu Pob Neges
+filterListBackUpMsg=Nid yw eich hidlau'n gweithio oherwydd nad oes modd darllen ffeil msg.FilterRules.dat sy'n cynnwys eich hidlau. Bydd ffeil msg.FilterRules.dat newydd yn cael ei greu a bydd yr hen ffeil yn cael ei gadw ar ffurf rulesbackup.dat yn yr un cyfeiriadur.
+customHeaderOverflow=Rydych wedi mynd dros yr uchafswm o 50 penynnau cyfaddasu. Tynnwch un neu ragor o'r penynnau cyfaddasu a cheisiwch eto.
+filterCustomHeaderOverflow=Mae eich hidlau wedi mynd dros y terfyn o 50 pennyn cyfaddasu. Golygwch y ffeil msgFilterRules.dat, sy'n cynnwys eich hidlau, i ddefnyddio llai o benynnau hidlo.
+invalidCustomHeader=Mae un o'ch hidlau'n cynnwys pennyn cyfaddasu sy'n cynnwys nod annilys, fel ':', nod anargraffadwy, nod nad yw'n ascii neu nod ascii wyth did. Golygwch y ffeil msgFilterRulesrules.dat, sy'n cynnwys eich hidlau, i dynnu'r nodau annilys o'ch pennyn cyfaddasu.
+continueFilterExecution=Methodd gosod yr hidl %S. Hoffech chi barhau i osod yr hidlau?
+promptTitle=Rhedeg Hidlau
+promptMsg=Rydych yn y broses o hidlo negeseuon.\nHoffech chi barhau i osod yr hidlau?
+stopButtonLabel=Atal
+continueButtonLabel=Parhau
+# LOCALIZATION NOTE(cannotEnableIncompatFilter)
+# %S=the name of the application
+cannotEnableIncompatFilter=Cafodd yr hidl ei greu gan fersiwn y dyfodol neu anghymarus o %S. Nid oes modd galluogi'r hidl am nad ydym yn gwybod sut mae ei weithredu.
+dontWarnAboutDeleteCheckbox=Peidiwch gofyn eto
+# LOCALIZATION NOTE(copyToNewFilterName)
+# %S=the name of the filter that is being copied
+copyToNewFilterName=Copi o %S
+# LOCALIZATION NOTE(contextPeriodic.label): Semi-colon list of plural forms.
+# #1=the number of minutes
+contextPeriodic.label=O bryd i'w gilydd, bob munud;O bryd i'w gilydd, bob #1 munud;O bryd i'w gilydd, bob #1 munud;O bryd i'w gilydd, bob #1 munud;O bryd i'w gilydd, bob #1 munud;O bryd i'w gilydd, bob #1 munud
+
+# LOCALIZATION NOTE(filterFailureWarningPrefix)
+# %1$S=filter error action
+# %2$S=error code as hexadecimal string.
+filterFailureWarningPrefix=Methodd Gweithredu'r Hidl: "%1$S" gyda error code=%2$S wrth geisio:
+filterFailureSendingReplyError=Gwall wrth anfon ateb
+filterFailureSendingReplyAborted=Ataliwyd anfon yr ateb
+filterFailureMoveFailed=Methodd y symud
+filterFailureCopyFailed=Methodd y copïo
+
+filterFailureAction=Methu gosod y weithred hidlo
+
+searchTermsInvalidTitle=Termau Chwilio yn Annilys
+# LOCALIZATION NOTE(searchTermsInvalidRule)
+# %1$S=search attribute name from the invalid rule
+# %2$S=search operator from the bad rule
+searchTermsInvalidRule=Nid oes modd cadw'r hidl gan fod y term chwilio "%1$S %2$S" yn annilys yn y cyd-destun cyfredol.
+# LOCALIZATION NOTE(filterActionOrderExplanation)
+# Keep the \n\n that mean 2 linebreaks.
+filterActionOrderExplanation=Pan fydd neges yn cydweddu'r hidl bydd gweithredoedd yn cael eu rhedeg yn y drefn yma:\n\n
+filterActionOrderTitle=Trefn gweithredu go iawn
+## LOCALIZATION NOTE(filterActionItem):
+# %1$S=sequence number of the action, %2$S=action text, %3$S=action argument
+filterActionItem=%1$S. %2$S %3$S\n
+
+## LOCALIZATION NOTE(filterCountVisibleOfTotal):
+# %1$S=number of matching filters, %2$S=total number of filters
+filterCountVisibleOfTotal=%1$S o %2$S
+## LOCALIZATION NOTE(filterCountItems):
+## Semicolon-separated list of singular and plural forms.
+## See: https://developer.mozilla.org/en/docs/Localization_and_Plurals
+## #1 is the count of items in the list.
+filterCountItems=0 eitemau;#1 eitem;#1 eitem;#1 eitem;#1 eitem;#1 eitem
+# for junk mail logging / mail filter logging
+# LOCALIZATION NOTE(junkLogDetectStr)
+# %1$S=author, %2$S=subject, %3$S=date
+junkLogDetectStr=Neges sbam wedi'i ganfod o %1$S - %2$S yn %3$S
+# LOCALIZATION NOTE(logMoveStr)
+# %1$S=message id, %2$S=folder URI
+logMoveStr=symud enw'r neges = %1$S i %2$S
+# LOCALIZATION NOTE(logCopyStr)
+# %1$S=message id, %2$S=folder URI
+logCopyStr=copïwyd enw neges = %1$S i %2$S
+# LOCALIZATION NOTE(filterLogLine):
+# %1$S=timestamp, %2$S=log message
+filterLogLine=[%1$S] %2$S
+# LOCALIZATION NOTE(filterMessage):
+# %1$S=filter name, %1$S=log message
+filterMessage=Neges o hidl "%1$S": %2$S
+# LOCALIZATION NOTE(filterLogDetectStr)
+# %1$S=filter name %2$S=author, %3$S=subject, %4$S=date
+filterLogDetectStr=Gosod hidl "%1$S" i neges gan %2$S - %3$S ar %4$S
+filterMissingCustomAction=Gweithred Cyfaddas Coll
+filterAction2=blaenoriaeth wedi newid
+filterAction3=dilëwyd
+filterAction4=marcio wedi darllen
+filterAction5=lladd edefyn
+filterAction6=edefyn yn cael ei wylio
+filterAction7=serenog
+filterAction8=tagiwyd
+filterAction9=atebwyd
+filterAction10=wedi'i anfon ymlaen
+filterAction11=atal gweithredu
+filterAction12=dilëwyd o'r gweinydd POP3
+filterAction13=gadawyd ar y gweinydd POP3
+filterAction14=sgôr sbam
+filterAction15=estyn y corff o weinydd POP3
+filterAction16=copïwyd i'r ffolder
+filterAction17=tagiwyd
+filterAction18=anwybyddwyd is-edefyn
+filterAction19=marcio heb ddarllen
+# LOCALIZATION NOTE(filterAutoNameStr)
+# %1$S=Header or item to match, e.g. "From", "Tag", "Age in days", etc.
+# %2$S=Operator, e.g. "Contains", "is", "is greater than", etc.
+# %3$S=Value, e.g. "Steve Jobs", "Important", "42", etc.
+filterAutoNameStr=%1$S %2$S: %3$S
diff --git a/l10n-cy/mail/chrome/messenger/folderProps.dtd b/l10n-cy/mail/chrome/messenger/folderProps.dtd
new file mode 100644
index 0000000000..0fa20ee045
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/folderProps.dtd
@@ -0,0 +1,74 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY folderProps.windowtitle.label           "Priodweddau">
+
+<!ENTITY generalInfo.label                       "Gwybodaeth Gyffredinol">
+<!ENTITY folderCharsetFallback2.label            "Amgodio Testun wrth Gefn:">
+<!ENTITY folderCharsetFallback2.accesskey        "G">
+<!ENTITY folderCharsetEnforce2.label             "Gosod amgodiad i bob neges yn y ffolder (bydd gosodiadau amgodio nodau negeseuon unigol ac awto-ganfod yn cael eu hanwybyddu)">
+<!ENTITY folderCharsetEnforce2.accesskey         "G">
+<!ENTITY folderRebuildSummaryFileTip2.label      "Ailadeiladu'r Mynegai Ffeil Cryno">
+<!ENTITY folderRebuildSummaryFile2.label         "Trwsio'r Ffolder">
+<!ENTITY folderRebuildSummaryFile2.accesskey     "T">
+<!ENTITY folderRebuildSummaryFile.explanation    "Weithiau bydd y ffeil mynegai'r ffolder (..msf) yn cael ei difrodi ac mae modd i negeseuon sy'n ymddangos ar goll neu ffeiliau sydd wedi'u dileu parhau i gael eu dangos; gall drwsio'r ffolder ddatrys y problemau hyn.">
+<!ENTITY folderIncludeInGlobalSearch.label       "Cynnwys y negeseuon yn y ffolder yng nghanlyniadau'r Chwilio Eang">
+<!ENTITY folderIncludeInGlobalSearch.accesskey   "n">
+
+<!ENTITY retention.label "Polisi Cadw">
+<!ENTITY retentionUseAccount.label  "Defnyddio gosodiadau fy nghyfrif">
+<!ENTITY retentionUseAccount.accesskey "D">
+<!ENTITY daysOld.label "diwrnod oed">
+<!ENTITY message.label "negeseuon">
+<!ENTITY retentionCleanup.label "I adfer lle ar ddisg, mae modd dileu hen negeseuon yn barhaol.">
+<!ENTITY retentionCleanupImap.label "I adfer lle ar ddisg, mae modd dileu hen negeseuon yn barhaol yn gopïau lleol a'r gwreiddiol ar y gweinydd pell.">
+<!ENTITY retentionCleanupPop.label "I adfer lle ar ddisg, mae modd dileu hen negeseuon yn barhaol gan gynnwys y gwreiddiol ar y gweinydd pell.">
+<!ENTITY retentionDeleteMsg.label "Dileu negeseuon mwy na">
+<!ENTITY retentionDeleteMsg.accesskey "i">
+<!ENTITY retentionKeepAll.label "Peidio dileu unrhyw neges">
+<!ENTITY retentionKeepAll.accesskey "P">
+<!ENTITY retentionKeepRecent.label "Dileu pob un heblaw'r mwyaf diweddar">
+<!ENTITY retentionKeepRecent.accesskey "l">
+<!ENTITY retentionApplyToFlagged.label "Cadw negeseuon serennog pob tro">
+<!ENTITY retentionApplyToFlagged.accesskey "s">
+
+<!ENTITY folderSynchronizationTab.label          "Cydweddu">
+<!ENTITY folderCheckForNewMessages2.label         "Wrth dderbyn negeseuon newydd ar gyfer y cyfrif hwn, gwirio'r ffolder bob tro">
+<!ENTITY folderCheckForNewMessages2.accesskey     "g">
+
+<!ENTITY offlineFolder.check.label               "Dewis y ffolder ar gyfer defnydd all-lein">
+<!ENTITY offlineFolder.check.accesskey           "D">
+<!ENTITY offlineFolder.button.label              "Llwytho i Lawr Nawr">
+<!ENTITY offlineFolder.button.accesskey          "L">
+
+<!ENTITY selectofflineNewsgroup.check.label      "Dewiswch y grŵp newyddion ar gyfer defnydd all-lein">
+<!ENTITY selectofflineNewsgroup.check.accesskey  "a">
+<!ENTITY offlineNewsgroup.button.label           "Llwytho i Lawr Nawr">
+<!ENTITY offlineNewsgroup.button.accesskey       "L">
+
+<!ENTITY folderProps.name.label                  "Enw:">
+<!ENTITY folderProps.name.accesskey              "E">
+<!ENTITY folderProps.color.label                 "Lliw Eicon:">
+<!ENTITY folderProps.color.accesskey             "E">
+<!ENTITY folderProps.reset.tooltip               "Adfer lliw rhagosodedig">
+<!ENTITY folderProps.location.label              "Lleoliad:">
+<!ENTITY folderProps.location.accesskey          "L">
+
+<!ENTITY folderSharingTab.label                  "Rhannu">
+<!ENTITY privileges.button.label                 "Breintiau…">
+<!ENTITY privileges.button.accesskey             "B">
+<!ENTITY permissionsDesc.label                   "Mae gennych y caniatâd canlynol:">
+<!ENTITY folderOtherUsers.label                  "Eraill sydd â mynediad i'r ffolder hon:">
+<!ENTITY folderType.label                        "Math o Ffolder:">
+
+<!ENTITY folderQuotaTab.label                    "Cwota">
+<!ENTITY folderQuotaUsage.label                  "Defnydd:">
+<!ENTITY folderQuotaStatus.label                 "Statws:">
+
+<!ENTITY numberOfMessages.label                  "Nifer o negeseuon:">
+<!-- LOCALIZATION NOTE: When the number of messages can't be determined, this string is displayed as the number -->
+<!ENTITY numberUnknown.label                     "anhysbys">
+<!ENTITY sizeOnDisk.label                        "Maint ar ddisg:">
+<!-- LOCALIZATION NOTE: When the size can't be determined, this string is displayed as the size -->
+<!ENTITY sizeUnknown.label                       "anhysbys">
diff --git a/l10n-cy/mail/chrome/messenger/folderWidgets.properties b/l10n-cy/mail/chrome/messenger/folderWidgets.properties
new file mode 100644
index 0000000000..fbf90ca56d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/folderWidgets.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE(globalInbox)
+# %S=name of the Local folders account
+globalInbox=Blwch Derbyn Popeth (%S)
+# LOCALIZATION NOTE(verboseFolderFormat): %1$S is folder name, %2$S is server name
+verboseFolderFormat=%1$S ar %2$S
+chooseFolder=Dewis Ffolder…
+chooseAccount=Dewis Cyfrif…
+noFolders=Dim ffolderi ar gael
diff --git a/l10n-cy/mail/chrome/messenger/folderpane.dtd b/l10n-cy/mail/chrome/messenger/folderpane.dtd
new file mode 100644
index 0000000000..cbf9b84618
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/folderpane.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!ENTITY nameColumn.label   "Enw"> 
+<!ENTITY unreadColumn.label "Heb ei Ddarllen"> 
+<!ENTITY totalColumn.label "Cyfanswm"> 
+<!ENTITY folderSizeColumn.label "Maint"> 
diff --git a/l10n-cy/mail/chrome/messenger/gloda.properties b/l10n-cy/mail/chrome/messenger/gloda.properties
new file mode 100644
index 0000000000..8a98fcf13a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/gloda.properties
@@ -0,0 +1,175 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (*.facetNameLabel): These are the labels used to label the facet
+#  displays in the global search facet display mechanism.  They should be
+#  compact descriptions of the facet type (e.g. "Folder", and don't need to
+#  refer to the objects being faceted (e.g. "Message" or "Mail").
+
+# LOCALIZATION NOTE (*.includeLabel): The label to use for the included group
+#  in the facet display. If not provided, we will fall back to
+#  "glodaFacetView.facets.included.fallbackLabel".
+
+# LOCALIZATION NOTE (*.excludeLabel): The label to use for the excluded group
+#  in the facet display. If not provided, we will fall back to
+#  "glodaFacetView.facets.excluded.fallbackLabel".
+
+# LOCALIZATION NOTE (*.remainderLabel): The label to use for the remaining items
+#  that are neither part of the included group or the excluded group in the
+#  facet display. If not provided, we will fall back to
+#  "glodaFacetView.facets.remainder.fallbackLabel".
+
+# LOCALIZATION NOTE (*.mustMatchLabel): The label to use for the popup menu
+#  to indicate that the results should be restricted to messages which match
+#  a particular value. If not provided, we will fall back to
+#  "glodaFacetView.facets.mustMatch.fallbackLabel".  #1, if present, is
+#  replaced by the value of the facet (name, folder, mailing list, etc.)
+
+# LOCALIZATION NOTE (*.cantMatchLabel): The label to use for the popup menu
+#  to indicate that the results should be restricted to messages which match
+#  a particular value. If not provided, we will fall back to
+#  "glodaFacetView.facets.cantMatch.fallbackLabel".  #1, if present, is
+#  replaced by the value of the facet (name, folder, mailing list, etc.)
+
+# LOCALIZATION NOTE (*.mayMatchLabel): The label to use for the popup menu
+#  to indicate that the results should no longer be restricted relative to
+#  this particular facet value. If not provided, we will fall back to
+#  "glodaFacetView.facets.mayMatch.fallbackLabel".  #1, if present, is
+#  replaced by the value of the facet (name, folder, mailing list, etc.)
+
+# LOCALIZATION NOTE (*.mustMatchSomeLabel): The label to use for the popup menu
+#  to indicate that the results should be restricted to messages which have
+#  _some_ value (e.g. at least one tag is set). If not provided, we will fall
+#  back to "glodaFacetView.facets.mustMatchSome.fallbackLabel".  #1, if present,
+#  is replaced by the value of the facet (name, folder, mailing list, etc.)
+
+# LOCALIZATION NOTE (*.mustMatchNoneLabel): The label to use for the popup menu
+#  to indicate that the results should be restricted to messages which have _no_
+#  value (e.g. no tags are set). If not provided, we will fall back to
+#  "glodaFacetView.facets.mustMatchNoneLabel.fallbackLabel".  #1, if present, is
+#  replaced by the value of the facet (name, folder, mailing list, etc.)
+
+# LOCALIZATION NOTE (*.mayMatchAnyLabel): The label to use for the popup menu
+#  to indicate that the results should not be restricted to messages which have
+#  any or no value (e.g. no requirements on any tags are set). If not provided,
+#  we will fall back to "glodaFacetView.facets.mayMatchAnyLabel.fallbackLabel".
+#  #1, if present, is replaced by the value of the facet (name, folder, mailing
+#  list, etc.)
+
+# LOCALIZATION NOTE (gloda.message.attr.account.*): Stores the account in which
+#  a message's folder is located.
+gloda.message.attr.account.facetNameLabel=Cyfrif
+gloda.message.attr.account.includeLabel=wedi'i storio yn unrhyw un o:
+gloda.message.attr.account.excludeLabel=heb ei storio yn:
+gloda.message.attr.account.remainderLabel=cyfrifon eraill:
+gloda.message.attr.account.mustMatchLabel=rhaid ei fod yn #1
+gloda.message.attr.account.cantMatchLabel=nid yw yn #1
+
+# LOCALIZATION NOTE (gloda.message.attr.folder.*): Stores the message folder in
+#  which the message is stored.
+gloda.message.attr.folder.facetNameLabel=Ffolder
+gloda.message.attr.folder.includeLabel=wedi'i storio yn unrhyw un o:
+gloda.message.attr.folder.excludeLabel=heb ei storio yn:
+gloda.message.attr.folder.remainderLabel=ffolderi eraill:
+gloda.message.attr.folder.mustMatchLabel=rhaid ei fod yn #1
+gloda.message.attr.folder.cantMatchLabel=nid yw yn #1
+
+# LOCALIZATION NOTE (gloda.message.attr.fromMe.*): Stores everyone involved
+#  with the message.  This means from/to/cc/bcc.
+gloda.message.attr.fromMe.facetNameLabel=Oddi wrthyf i
+
+# LOCALIZATION NOTE (gloda.message.attr.toMe.*): Stores everyone involved
+#  with the message.  This means from/to/cc/bcc.
+gloda.message.attr.toMe.facetNameLabel=Ataf i
+
+# LOCALIZATION NOTE (gloda.message.attr.involves.*): Stores everyone involved
+#  with the message.  This means from/to/cc/bcc.
+gloda.message.attr.involves.facetNameLabel=Pobl
+gloda.message.attr.involves.includeLabel=yn ymwneud â:
+gloda.message.attr.involves.excludeLabel=ddim yn cynnwys:
+gloda.message.attr.involves.remainderLabel=cyfrannwr eraill:
+gloda.message.attr.involves.mustMatchLabel=rhaid ymwneud â #1
+gloda.message.attr.involves.cantMatchLabel=nid yn ymwneud â #1
+
+# LOCALIZATION NOTE (gloda.message.attr.date.*): Stores the date of the message.
+#  Thunderbird normally stores the date the message claims it was composed
+#  according to the "Date" header.  This is not the same as when the message
+#  was sent or when it was eventually received by the user.  In the future we
+#  may change this to be one of the other dates, but not anytime soon.
+gloda.message.attr.date.facetNameLabel=Dyddiad
+
+# LOCALIZATION NOTE (gloda.message.attr.attachmentTypes.*): Stores the list of
+#  MIME types (ex: image/png, text/plain) of real attachments (not just part of
+#  the message content but explicitly named attachments) on the message.
+#  Although we hope to be able to provide localized human-readable explanations
+#  of the MIME type (ex: "PowerPoint document"), I don't know if that is going
+#  to happen.
+gloda.message.attr.attachmentTypes.facetNameLabel=Atodiadau
+
+# LOCALIZATION NOTE (gloda.message.attr.mailing-list.*): Stores the mailing
+#  lists detected in the message.  This will normally be the e-mail address of
+#  the mailing list and only be detected in messages received from the mailing
+#  list.  Extensions may contribute additional detected mailing-list-like
+#  things.
+gloda.message.attr.mailing-list.facetNameLabel=Rhestr E-bost
+gloda.message.attr.mailing-list.noneLabel=Dim
+gloda.message.attr.mailing-list.includeLabel=wedi derbyn o unrhyw un o:
+gloda.message.attr.mailing-list.excludeLabel=heb ei dderbyn ar unrhyw un o:
+gloda.message.attr.mailing-list.remainderLabel=rhestrau e-bostio eraill:
+gloda.message.attr.mailing-list.mustMatchLabel=rhaid ei fod yn #1
+gloda.message.attr.mailing-list.cantMatchLabel=nid yw yn #1
+gloda.message.attr.mailing-list.mustMatchSomeLabel=rhaid ei fod mewn rhestr e-bost
+gloda.message.attr.mailing-list.mustMatchNoneLabel=nid yw mewn rhestr e-bostio
+
+# LOCALIZATION NOTE (gloda.message.attr.tag.*): Stores the tags applied to the
+#  message.  Notably, gmail's labels are not currently exposed via IMAP and we
+#  do not do anything clever with gmail, so this is independent of gmail labels
+#  This may change in the future, but it's a safe bet it's not happening on
+#  Thunderbird's side prior to 3.0.
+gloda.message.attr.tag.facetNameLabel=Tagiau
+gloda.message.attr.tag.noneLabel=Dim
+gloda.message.attr.tag.includeLabel=tagio o unrhyw un o:
+gloda.message.attr.tag.excludeLabel=heb ei dagio:
+gloda.message.attr.tag.remainderLabel=tagiau eraill:
+gloda.message.attr.tag.mustMatchLabel=rhaid fod wedi tagio #1
+gloda.message.attr.tag.cantMatchLabel=nid yw wedi'i dagio #1
+gloda.message.attr.tag.mustMatchSomeLabel=rhaid fod wedi tagio
+gloda.message.attr.tag.mustMatchNoneLabel=nid yw wedi'i dagio
+
+# LOCALIZATION NOTE (gloda.message.attr.star.*): Stores whether the message is
+#  starred or not, as indicated by a pretty star icon.  In the past, the icon
+#  used to be a flag.  The IMAP terminology continues to be "flagged".
+gloda.message.attr.star.facetNameLabel=Serennog
+
+# LOCALIZATION NOTE (gloda.message.attr.read.*): Stores whether the user has
+#  read the message or not.
+gloda.message.attr.read.facetNameLabel=Darllenwyd
+
+# LOCALIZATION NOTE (gloda.message.attr.repliedTo.*): Stores whether we believe
+#  the user has ever replied to the message.  We normally show a little icon in
+#  the thread pane when this is the case.
+gloda.message.attr.repliedTo.facetNameLabel=Atebwyd i
+
+# LOCALIZATION NOTE (gloda.message.attr.forwarded.*): Stores whether we believe
+#  the user has ever forwarded the message.  We normally show a little icon in
+#  the thread pane when this is the case.
+gloda.message.attr.forwarded.facetNameLabel=Ymlaen
+
+# LOCALIZATION NOTE (gloda.mimetype.category.*.label): Map categories of MIME
+#  types defined in MimeTypeCategories.jsm to labels.
+# LOCALIZATION NOTE (gloda.mimetype.category.archives.label): Archive is
+#  referring to things like zip files, tar files, tar.gz files, etc.
+gloda.mimetype.category.archives.label=Archifau
+gloda.mimetype.category.documents.label=Dogfennau
+gloda.mimetype.category.images.label=Delweddau
+# LOCALIZATION NOTE (gloda.mimetype.category.media.label): Media is meant to
+#  encompass both audio and video.  This is because video and audio streams are
+#  frequently stored in the same type of container and we cannot rely on the
+#  sending e-mail client to have been clever enough to figure out what was
+#  really in the file.  So we group them together.
+gloda.mimetype.category.media.label=Cyfrwng (Sain, Fideo)
+gloda.mimetype.category.pdf.label=Ffeiliau PDF
+# LOCALIZATION NOTE (gloda.mimetype.category.other.label): Other is the category
+#  for MIME types that we don't really know what it is.
+gloda.mimetype.category.other.label=Arall
diff --git a/l10n-cy/mail/chrome/messenger/glodaComplete.properties b/l10n-cy/mail/chrome/messenger/glodaComplete.properties
new file mode 100644
index 0000000000..e407e1a7f1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/glodaComplete.properties
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (glodaComplete.messagesTagged.label): The label used
+#  in the autocomplete widget to refer to a query for all messages tagged
+#  by a particular tag (replacing #1).
+glodaComplete.messagesTagged.label=Negeseuon wedi'u tagio: #1
+
+# LOCALIZATION NOTE (glodaComplete.messagesMentioning.label): The label used
+#  in the autocomplete widget to refer to a search for all messages mentioning
+#  a particular word (replacing #1).
+glodaComplete.messagesMentioning.label=Negeseuon yn sôn am: #1
+
+# LOCALIZATION NOTE (glodaComplete.messagesWithMany.label): The label used
+#  in the autocomplete widget to refer to a search for all messages mentioning
+#  a set of words, or a phrase containing multiple words (e.g. "red pepper")
+#  We use the same words in en-US, but maybe that's not always true.
+glodaComplete.messagesMentioningMany.label=Negeseuon yn sôn am: #1
diff --git a/l10n-cy/mail/chrome/messenger/glodaFacetView.dtd b/l10n-cy/mail/chrome/messenger/glodaFacetView.dtd
new file mode 100644
index 0000000000..5bf0e3c049
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/glodaFacetView.dtd
@@ -0,0 +1,29 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE (glodaFacetView.filters.label): Label at the top of the
+     faceting sidebar.  Serves as a header both for the checkboxes under it as
+     well for labeled facets with multiple options. -->
+<!ENTITY glodaFacetView.filters.label "Hidlau">
+
+<!-- LOCALIZATION NOTE (glodaFacetView.loading.label): Label that appears when
+     the search results take a long time to appear. -->
+<!ENTITY glodaFacetView.loading.label "Chwilio&#8230;">
+
+<!-- LOCALIZATION NOTE (glodaFacetView.empty.label): Label that appears when
+     there are no results that match the search query. -->
+<!ENTITY glodaFacetView.empty.label "Dim negeseuon yn cyd-fynd â'ch chwilio">
+
+<!-- LOCALIZATION NOTE (glodaFacetView.pageMore.label): Label at the bottom
+     of the results list to show more hits. -->
+<!ENTITY glodaFacetView.pageMore.label "Rhagor »">
+
+<!-- LOCALIZATION NOTE(glodaFacetView.results.message.openEmailAsList.label2): The
+     label for the button/link that causes us to display all of the emails in
+     the active set in a new thread pane display tab. -->
+<!ENTITY glodaFacetView.openEmailAsList.label "Dangos y canlyniadau fel rhestr">
+
+<!-- LOCALIZATION NOTE(glodaFacetView.results.message.openEmailAsList.tooltip):
+     The tooltip to display when hovering over the openEmailAsList label. -->
+<!ENTITY glodaFacetView.openEmailAsList.tooltip "Dangos yr holl negeseuon e-bost yn y set weithredol mewn tab newydd">
diff --git a/l10n-cy/mail/chrome/messenger/glodaFacetView.properties b/l10n-cy/mail/chrome/messenger/glodaFacetView.properties
new file mode 100644
index 0000000000..eaffc78d45
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/glodaFacetView.properties
@@ -0,0 +1,171 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (glodaFacetView.tab.query.label):
+#  The tab title to display for tabs that are based on a gloda (global database)
+#  query or collection rather than a user search.  At some point we might try
+#  and explain what the query/collection is in automatic fashion, but not today.
+glodaFacetView.tab.query.label=Chwilio
+
+# LOCALIZATION NOTE (glodaFacetView.tab.search.label):
+#  The tab title to display for tabs with a new gloda (global database)
+#  user search (rather than a query or collection) without a search string.
+#  After the search has been started, we just display the search string entered
+#  by the user.
+glodaFacetView.tab.search.label=Chwilio
+
+# LOCALIZATION NOTE(glodaFacetView.search.label2):
+#  The heading for the search page.
+#  A short description of user's search query will be appended.
+glodaFacetView.search.label2=Canlyniadau:
+
+# LOCALIZATION NOTE(glodaFacetView.constraints.query.fulltext.label):
+#  The label to display to describe when our base query was a fulltext search
+#  across messages.  The value is displayed following the label.
+glodaFacetView.constraints.query.fulltext.label=Chwilio am #1
+glodaFacetView.constraints.query.fulltext.andJoinWord=a
+glodaFacetView.constraints.query.fulltext.orJoinWord=neu
+
+# LOCALIZATION NOTE(glodaFacetView.constraints.query.initial):
+#  The label to display to describe when our base query is not a full-text
+#  search.  Additional labels are appended describing each constraint.
+glodaFacetView.constraints.query.initial=Chwilio am negeseuon
+
+# LOCALIZATION NOTE(glodaFacetView.constraints.query.involves.label):
+#  The label to display to describe when our base query was on messages
+#  involving a given contact from the address book.  The value is displayed
+#  where the #1 is.
+glodaFacetView.constraints.query.involves.label=ymwneud â #1
+
+# LOCALIZATION NOTE(glodaFacetView.constraints.query.contact.label):
+#  The label to display to describe when our base query was on messages
+#  tagged with a specific tag.  The tag is displayed following the label.
+glodaFacetView.constraints.query.tagged.label=tagiwyd:
+
+
+# LOCALIZATION NOTE (glodaFacetView.facets.mode.top.listAllLabel): The label to
+#  use when we are only displaying the top entries for a facet.  When the
+#  label is clicked on, it results in us displaying all of the values for that
+#  facet.  The value "#1" (if present) is replaced with the total number of
+#  values that will be displayed (rather than the number currently hidden).
+# This string supports pluralization.  See
+#  https://developer.mozilla.org/en/Localization_and_Plurals for details on
+#  how this stuff works.
+glodaFacetView.facets.mode.top.listAllLabel=Rhestru dim;Rhestru'r #1 i gyd;Rhestru'r #1 i gyd;Rhestru'r #1 i gyd;Rhestru'r #1 i gyd;Rhestru'r #1 i gyd
+
+# LOCALIZATION NOTE (glodaFacetView.facets.included.fallbackLabel): The label to
+#  use for groups in a facet that have been explicitly included by the user if
+#  there is no explicit attribute "includeLabel" defined.  (The explicit label
+#  would be named "gloda.message.attr.ATTRIBUTE.includeLabel".)
+glodaFacetView.facets.included.fallbackLabel=cynnwys unrhyw un o:
+# LOCALIZATION NOTE (glodaFacetView.facets.excluded.fallbackLabel): The label to
+#  use for groups in a facet that have been explicitly excluded by the user if
+#  there is no explicit attribute "excludeLabel" defined.  (The explicit label
+#  would be named "gloda.message.attr.ATTRIBUTE.excludeLabel".)
+glodaFacetView.facets.excluded.fallbackLabel=peidio cynnwys:
+# LOCALIZATION NOTE (glodaFacetView.facets.remainder.fallbackLabel): The label
+#  to use for groups in a facet that are neither part of the included group or
+#  the excluded group if there is no explicit attribute "remainderLabel"
+#  defined.  (The explicit label would be named
+#  "gloda.message.attr.ATTRIBUTE.remainderLabel".)
+glodaFacetView.facets.remainder.fallbackLabel=eraill:
+
+# LOCALIZATION NOTE (glodaFacetView.facets.mustMatchLabel.fallbackLabel): The label
+#  to use to restrict a facet by a particular value if there is no explicit
+#  attribute "mustMatchLabel" defined.  (The explicit label would be named
+#  "gloda.message.attr.ATTRIBUTE.mustMatchLabel".)
+glodaFacetView.facets.mustMatchLabel.fallbackLabel=rhaid cydweddu â #1
+glodaFacetView.facets.mustMatchNoneLabel.fallbackLabel=methu cael gwerth
+
+# LOCALIZATION NOTE (glodaFacetView.facets.cantMatchLabel.fallbackLabel): The label
+#  to use to restrict a facet by the absence of a particular value if there is
+#  no explicit attribute "cantMatchLabel" defined.  (The explicit label would be
+#  named "gloda.message.attr.ATTRIBUTE.cantMatchLabel".)
+glodaFacetView.facets.cantMatchLabel.fallbackLabel=methu cydweddu â #1
+glodaFacetView.facets.mustMatchSomeLabel.fallbackLabel=rhaid cael gwerth
+
+# LOCALIZATION NOTE (glodaFacetView.facets.mayMatchLabel.fallbackLabel): The label
+#  to use to undo the restriction of a facet by a particular value if there is
+#  no explicit attribute "mayMatchLabel" defined.  (The explicit label would be
+#  named "gloda.message.attr.ATTRIBUTE.mayMatchLabel".)
+glodaFacetView.facets.mayMatchLabel.fallbackLabel=tynnu'r cyfyngiad
+glodaFacetView.facets.mayMatchAnyLabel.fallbackLabel=tynnu'r cyfyngiad
+
+# LOCALIZATION NOTE (glodaFacetView.facets.noneLabel): The text to display when
+#  a facet needs to indicate that an attribute omitted a value or was otherwise
+#  empty.
+glodaFacetView.facets.noneLabel=Dim
+
+# LOCALIZATION NOTE (glodaFacetView.facets.filter.attachmentTypes.allLabel):
+#  The label to use when all types of attachments are being displayed.
+glodaFacetView.facets.filter.attachmentTypes.allLabel=Unrhyw Fath
+
+# LOCALIZATION NOTE (glodaFacetView.result.message.fromLabel): Used in the
+#  faceted search message display to indicate the author of a message.
+# An example usage is  "from: Bob".
+glodaFacetView.result.message.fromLabel=oddi wrth:
+
+# LOCALIZATION NOTE (glodaFacetView.result.message.toLabel): Used in the
+#  faceted search message display to indicate the recipients of a message.
+# An example usage is  "to: Bob, Chuck, Don".
+glodaFacetView.result.message.toLabel=at: 
+
+# LOCALIZATION NOTE (glodaFacetView.result.message.noSubject): Used in the
+#  faceted search message display to act as a click target for messages with
+#  no subject.
+glodaFacetView.result.message.noSubject=(dim pwnc)
+
+# LOCALIZATION NOTE(glodaFacetView.results.header.countLabel):
+# This label is displayed above the list of result messages; it tells the user
+#  how many messages we are displaying in the list out of the total number of
+#  messages in the active set (the set of messages remaining after the
+#  application of the facet constraints.)
+# The goal of the various sub-parts here is to make a label along the lines of
+#  "M of N".  Because there are two numbers, this is split into two parts,
+#  'NMessages' for what in English is just the first number and 'ofN' for the
+#  "of N" part.  We then use 'grouping' to decide how to combine the two. This
+#  was suggested by Rimas Kudelis.
+# LOCALIZATION NOTE(glodaFacetView.results.header.countLabel.NMessages):
+#  The first part of the countLabel string (although you can change the order
+#  in 'grouping').  This is pluralized using the mechanism described at
+#  https://developer.mozilla.org/en/Localization_and_Plurals.  We replace
+#  "#1" with the number of messages being shown in the result list.
+glodaFacetView.results.header.countLabel.NMessages=#1;#1;#1;#1;#1;#1
+# LOCALIZATION NOTE(glodaFacetView.results.header.countLabel.ofN):
+#  The second part of the countLabel string (although you can change the order
+#  in 'grouping').  This is pluralized using the mechanism described at
+#  https://developer.mozilla.org/en/Localization_and_Plurals.  We replace
+#  "#1" with the total number of messagse in the active set.
+glodaFacetView.results.header.countLabel.ofN=o #1;o #1;o #1;o #1;o #1;o #1
+# LOCALIZATION NOTE(glodaFacetView.results.header.countLabel.grouping):
+#  Combines the pluralized
+#  "glodaFacetView.results.header.countLabel.NMessages" string (as #1) with
+#  the pluralized "glodaFacetView.results.header.countLabel.ofN" (as #2)
+#  to make a single label.
+glodaFacetView.results.header.countLabel.grouping=#1 #2
+
+glodaFacetView.results.message.timeline.label=Toglo'r llinell amser
+# LOCALIZATION NOTE(glodaFacetView.results.message.sort.relevance2):
+# a clickable label causing the sort to be done by most relevant messages first.
+glodaFacetView.results.message.sort.relevance2=Trefnu yn ôl Perthnasedd
+# LOCALIZATION NOTE(glodaFacetView.results.message.sort.date2):
+# a clickable label causing the sort to be done by most recent messages first.
+glodaFacetView.results.message.sort.date2=Trefnu yn ôl Dyddiad
+
+# LOCALIZATION NOTE(glodaFacetView.results.message.recipientSeparator): This is
+# the string in between the names of recipients (see
+# glodaFacetView.results.message.andOthers for more information).  The \u0020
+# character is a Unicode space character, which is needed as otherwise the
+# trailing whitespace is trimmed before it gets to the code.
+glodaFacetView.results.message.recipientSeparator=,\u0020
+
+# LOCALIZATION NOTE(glodaFacetView.results.message.andOthers):
+# When a message has too many recipients, we only show the first few and then
+# display this label to express how many are not displayed.  So if a message
+# has 5 recipients, we might only show the first 3, and then use this label
+# to indicate that there are 2 that are not displayed.  This string can be
+# pluralized; see https://developer.mozilla.org/en/Localization_and_Plurals
+# for details on how to do that. Note that in English, we use the "serial
+# comma", but other languages may not need a leading separator there.
+glodaFacetView.results.message.andOthers=, a #1 arall;, ac #1 arall;, a #1 arall;, a #1 arall;, a #1 arall;, a #1 arall
diff --git a/l10n-cy/mail/chrome/messenger/imAccountWizard.dtd b/l10n-cy/mail/chrome/messenger/imAccountWizard.dtd
new file mode 100644
index 0000000000..52606e366c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/imAccountWizard.dtd
@@ -0,0 +1,32 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label            "Dewin Cyfrif Sgwrsio">
+
+<!ENTITY accountProtocolTitle.label   "Rhwydwaith sgwrsio">
+<!ENTITY accountProtocolInfo.label    "Dewiswch rwydwaith eich cyfrif sgwrsio.">
+<!ENTITY accountProtocolField.label   "Rhwydwaith:">
+<!ENTITY accountProtocolGetMore.label "Estyn rhagor…">
+
+<!ENTITY accountUsernameTitle.label   "Enw Defnyddiwr">
+<!ENTITY accountUsernameDuplicate.label "Mae'r cyfrif yma wedi'i ffurfweddu yn barod!">
+
+<!ENTITY accountPasswordTitle.label   "Cyfrinair">
+<!ENTITY accountPasswordInfo.label    "Rhowch eich cyfrinair yn y blwch isod.">
+<!ENTITY accountPasswordField.label   "Cyfrinair:">
+<!ENTITY accountPasswordManager.label "Bydd y cyfrinair rhoddwyd yma yn cael ei gadw o fewn y Rheolwr Cyfrineiriau. Gadewch y blwch yn wag os ydych eisiau cael eich annog am eich cyfrinair bob tro mae'r cyfrif yn cael ei gysylltu.">
+
+<!ENTITY accountAdvancedTitle.label   "Dewisiadau Uwch">
+<!ENTITY accountAdvancedInfo.label    "Teimlwch yn rhydd i hepgor y cam yma.">
+<!ENTITY accountAdvanced.newMailNotification.label   "Hysbysu am E-bost newydd">
+<!ENTITY accountAliasGroupbox.caption "Ffugenw Lleol">
+<!ENTITY accountAliasField.label      "Ffugenw:">
+<!ENTITY accountAliasInfo.label       "Dim ond pan fyddwch yn siarad yn ystod eich trafodaethau fydd hwn yn cael ei ddangos, ni fydd y cysylltiadau pell yn ei weld.">
+<!ENTITY accountProxySettings.caption "Gosodiadau'r Dirprwy">
+<!ENTITY accountProxySettings.change.label     "Newid…">
+<!ENTITY accountProxySettings.change.accessKey "N">
+
+<!ENTITY accountSummaryTitle.label   "Crynodeb">
+<!ENTITY accountSummaryInfo.label    "Mae crynodeb o'r wybodaeth rydych wedi'i gyflwyno'n cael ei ddangos isod. Gwiriwch y cynnwys cyn i'r cyfrif gael ei greu.">
+<!ENTITY accountSummary.connectNow.label "Cysylltu â'r cyfrif nawr.">
diff --git a/l10n-cy/mail/chrome/messenger/imAccounts.properties b/l10n-cy/mail/chrome/messenger/imAccounts.properties
new file mode 100644
index 0000000000..7a14e00c56
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/imAccounts.properties
@@ -0,0 +1,63 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (protoOptions):
+# %S is replaced by the name of a protocol
+protoOptions=Dewisiadau %S
+accountUsername=Enw Defnyddiwr:
+# LOCALIZATION NOTE (accountColon):
+# This string is used to append a colon after the label of each
+# option. It's localizable so that the typography can be adapted.
+accountColon=%S:
+# LOCALIZATION NOTE (accountUsernameInfo):
+# %S is replaced by the name of a protocol
+accountUsernameInfo=Rhowch enw defnyddiwr eich cyfrif %S.
+# LOCALIZATION NOTE (accountUsernameInfoWithDescription):
+# %1$S is a hint for the expected format of the username
+# %2$S is the name of a protocol
+accountUsernameInfoWithDescription=Rhowch enw defnyddiwr (%1$S) eich cyfrif %2$S.
+
+# LOCALIZATION NOTE (account.connection.error):
+# %S is the error message.
+account.connection.error=Gwall: %S
+# LOCALIZATION NOTE (account.connection.errorUnknownPrpl)
+# %S is the id (not very user friendly; hence the quotes) of the missing plugin.
+account.connection.errorUnknownPrpl=Dim protocol ategyn '%S'.
+account.connection.errorEnteringPasswordRequired=Mae angen cyfrinair i gysylltu â'r cyfrif.
+account.connection.errorCrashedAccount=Digwyddodd chwalfa wrth gysylltu â'r cyfrif.
+# LOCALIZATION NOTE (account.connection.progress):
+# %S is a message indicating progress of the connection process
+account.connection.progress=Cysylltu: %S…
+account.connecting=Cysylltu…
+account.connectedForSeconds=Wedi cysylltu am ychydig eiliadau.
+# LOCALIZATION NOTE (account.connectedFor{Double,Single},
+#                    account.reconnectIn{Double,Single}):
+# Each pair of %S is a number followed by a unit. The units are
+# already localized in a downloads.properties file of the toolkit.
+account.connectedForDouble=Wedi cysylltu ers %1$S %2$S a %3$S %4$S.
+account.connectedForSingle=Wedi cysylltu ers tua %1$S %2$S.
+account.reconnectInDouble=Ailgysylltu ymhen %1$S %2$S a %3$S %4$S.
+account.reconnectInSingle=Ailgysylltu ymhen %1$S %2$S.
+
+requestAuthorizeTitle=Cais dilysu
+# LOCALIZATION NOTE (requestAuthorizeAllow, requestAuthorizeDeny):
+# the & symbol indicates the position of the character that should be
+# used as the accesskey for this button.
+requestAuthorizeAllow=&Caniatáu
+requestAuthorizeDeny=&Gwrthod
+# LOCALIZATION NOTE (requestAuthorizeText):
+# %S is a contact username.
+requestAuthorizeText=Mae %S wedi eich ychwanegu at ei rhestr ffrindiau, hoffech chi ganiatáu iddo/iddi eich gweld chi?
+
+accountsManager.notification.button.accessKey=C
+accountsManager.notification.button.label=Cysylltu Nawr
+accountsManager.notification.userDisabled.label=Rydych wedi anablu cysylltu awtomatig.
+accountsManager.notification.safeMode.label=Mae Gosodiadau Cysylltu Awtomatig wedi'u hanwybyddu gan fod y rhaglen yn rhedeg yn y Modd Diogel.
+accountsManager.notification.startOffline.label=Mae Gosodiadau Cysylltu Awtomatig wedi'u hanwybyddu gan fod y rhaglen wedi ei chychwyn yn y Modd Diogel.
+accountsManager.notification.crash.label=Daeth y rhediad diwethaf i ben yn annisgwyl wrth geisio cysylltu. Mae Cysylltu Awtomatig wedi'i anablu er mwyn rhoi cyfle i chi Olygu eich Gosodiadau.
+# LOCALIZATION NOTE (accountsManager.notification.singleCrash.label): Semi-colon list of plural forms.
+#  See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+#  #1 is the number of accounts that are suspected to have caused a crash.
+accountsManager.notification.singleCrash.label=Daeth rhediad blaenorol i ben yn annisgwyl wrth geisio cysylltu cyfrifon newydd neu rhai wedi eu golygu. Nid yw wedi'i gysylltu er mwyn rhoi cyfle i chi Olygu eich Gosodiadau.;Daeth rhediad blaenorol  i ben yn annisgwyl wrth geisio cysylltu #1 cyfrif newydd neu wedi'u golygu. Nid ydynt wedi eu cysylltu er mwyn rhoi cyfle i chi Olygu eu Gosodiadau.;Daeth rhediad blaenorol  i ben yn annisgwyl wrth geisio cysylltu #1 gyfrif newydd neu wedi'u golygu. Nid ydynt wedi eu cysylltu er mwyn rhoi cyfle i chi Olygu eu Gosodiadau.;Daeth rhediad blaenorol  i ben yn annisgwyl wrth geisio cysylltu #1 cyfrif newydd neu wedi'u golygu. Nid ydynt wedi eu cysylltu er mwyn rhoi cyfle i chi Olygu eu Gosodiadau.;Daeth rhediad blaenorol  i ben yn annisgwyl wrth geisio cysylltu #1 cyfrif newydd neu wedi'u golygu. Nid ydynt wedi eu cysylltu er mwyn rhoi cyfle i chi Olygu eu Gosodiadau.;Daeth rhediad blaenorol  i ben yn annisgwyl wrth geisio cysylltu #1 cyfrif newydd neu wedi'u golygu. Nid ydynt wedi eu cysylltu er mwyn rhoi cyfle i chi Olygu eu Gosodiadau.
+accountsManager.notification.other.label=Mae cysylltu awtomatig wedi'i analluogi.
diff --git a/l10n-cy/mail/chrome/messenger/imapMsgs.properties b/l10n-cy/mail/chrome/messenger/imapMsgs.properties
new file mode 100644
index 0000000000..27b7874ef7
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/imapMsgs.properties
@@ -0,0 +1,266 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the imap code to display progress/status/error messages
+#
+
+#LOCALIZATION NOTE(imapAlertDialogTile): Do not translate the word "%S"
+# below. Place the word %S where the account name should appear.
+imapAlertDialogTitle=Rhybudd cyfrif %S
+
+# Status - opening folder
+imapStatusSelectingMailbox=Agor ffolder %S…
+
+# Status - create folder
+imapStatusCreatingMailbox=Creu ffolder…
+
+# Status - deleting a folder
+# LOCALIZATION NOTE (imapStatusDeletingMailbox): The "%S" below should not be translated.
+# Instead, insert "%S" in your translation where you wish to display the name
+# of the folder being deleted.
+imapStatusDeletingMailbox=Dileu ffolder %S…
+
+# Status - renaming mailbox
+# LOCALIZATION NOTE (imapStatusRenamingMailbox): The "%S" below should not be translated.
+# Instead, insert "%S" in your translation where you wish to display the name
+# of the folder being renamed.
+imapStatusRenamingMailbox=Ailenwi ffolder %S…
+
+# Status - looking for mailboxes
+imapStatusLookingForMailbox=Chwilio am ffolderi…
+
+# Status - subscribing to mailbox
+# LOCALIZATION NOTE (imapStatusSubscribeToMailbox): The "%S" below should not be translated.
+# Instead, insert "%S" in your translation where you wish to display the name
+# of the folder being subscribed to.
+imapStatusSubscribeToMailbox=Tanysgrifio i ffolder %S…
+
+# Status - unsubscribing from mailbox
+# LOCALIZATION NOTE (imapStatusUnsubscribeMailbox): The "%S" below should not be translated.
+# Instead, insert "%S" in your translation where you wish to display the name
+# of the folder being unsubscribed from.
+imapStatusUnsubscribeMailbox=Dad-danysgrifio o ffolder %S…
+
+# Status - searching imap folder
+imapStatusSearchMailbox=Chwilio'r ffolder…
+
+# Status - closing a folder
+imapStatusCloseMailbox=Cau ffolder…
+
+# Status - compacting a folder
+imapStatusExpungingMailbox=Cywasgu ffolder…
+
+# Status - logging out
+imapStatusLoggingOut=Allgofnodi…
+
+# Status - checking server capabilities
+imapStatusCheckCompat=Gwirio galluoedd gweinydd e-bost…
+
+# Status - logging on
+imapStatusSendingLogin=Anfon gwybodaeth dilysu mewngofnodi…
+
+# Status - auth logon
+imapStatusSendingAuthLogin=Anfon gwybodaeth mewngofnodi…
+
+imapDownloadingMessage=Llwytho neges i lawr…
+
+# LOCALIZATION NOTE (imapGettingACLForFolder): Do not translate the word "ACL" below.
+imapGettingACLForFolder=Estyn ffolder ACL…
+
+imapGettingServerInfo=Estyn Gwybodaeth Ffurfweddu Gweinydd…
+
+imapGettingMailboxInfo=Estyn Gwybodaeth Ffurfweddu Blwch E-bost…
+
+imapEmptyMimePart=Bydd corff yr e-bost yn cael ei lwytho i lawr yn ôl y gofyn.
+
+# LOCALIZATION NOTE (imapReceivingMessageHeaders3): Do not translate the words "%1$S", "%2$S", and "%3$S" below.
+# Place the word %1$S in your translation where the number of the header being downloaded should appear.
+# Place the word %2$S in your translation where the total number of headers to be downloaded should appear.
+# Place the word %3$S in your translation where the name of the folder being processed should appear.
+# Note: The account name and separators (e.g. colon, space) are automatically added to the status message.
+# Example: "Joe's Account: Downloading message header 100 of 1000 in Drafts…"
+imapReceivingMessageHeaders3=Llwytho %1$S pennyn neges i lawr o %2$S yn %3$S…
+
+# LOCALIZATION NOTE (imapReceivingMessageFlags3): Do not translate the words "%1$S", "%2$S", and "%3$S" below.
+# Place the word %1$S in your translation where the number of the flag being downloaded should appear.
+# Place the word %2$S in your translation where the total number of flags to be downloaded should appear.
+# Place the word %3$S in your translation where the name of the folder being processed should appear.
+# Note: The account name and separators (e.g. colon, space) are automatically added to the status message.
+# Example: "Jim's Account: Downloading message flag 100 of 1000 in INBOX…"
+imapReceivingMessageFlags3=Llwytho %1$S baner neges i lawr o %2$S yn %3$S…
+
+imapDeletingMessages=Dileu negeseuon…
+
+imapDeletingMessage=Dileu neges…
+
+# LOCALIZATION NOTE (imapMovingMessages): Do not translate the word "%S" below.
+# Place the word %S in your translation where the name of the folder should appear.
+imapMovingMessages=Symud negeseuon i %S…
+
+# LOCALIZATION NOTE (imapMovingMessage): Do not translate the word "%S" below.
+# Place the word %S in your translation where the name of the folder should appear.
+imapMovingMessage=Symud neges i %S…
+
+# LOCALIZATION NOTE (imapCopyingMessages): Do not translate the word "%S" below.
+# Place the word %S in your translation where the name of the folder should appear.
+imapCopyingMessages=Copïo negeseuon i %S…
+
+# LOCALIZATION NOTE (imapCopyingMessage): Do not translate the word "%S" below.
+# Place the word %S in your translation where the name of the folder should appear.
+imapCopyingMessage=Copïo neges i %S…
+
+# LOCALIZATION NOTE (imapFolderReceivingMessageOf3): Do not translate the words "%1$S", "%2$S", and "%3$S" below.
+# Place the word %1$S in your translation where the number of the message being downloaded should appear.
+# Place the word %2$S in your translation where the total number of messages to be downloaded should appear.
+# Place the word %3$S in your translation where the name of the folder being processed should appear.
+# Note: The account name and separators (e.g. colon, space) are automatically added to the status message.
+# Example: "Juan's Account: Downloading message 100 of 1000 in Sent…"
+imapFolderReceivingMessageOf3=Llwytho %1$S neges i lawr o %2$S yn %3$S…
+
+# LOCALIZATION NOTE (imapDiscoveringMailbox): Do not translate the word "%S" below.
+# Place the word %S in your translation where the name of the folder should appear.
+imapDiscoveringMailbox=Wedi canfod ffolder: %S
+
+# LOCALIZATION NOTE (imapEnterServerPasswordPrompt): Do not translate the words %1$S and %2$S below.
+# Place the word %1$S in your translation where the username should appear.
+# Place the word %2$S in your translation where the servername should appear.
+imapEnterServerPasswordPrompt=Rhowch eich cyfrinair ar gyfer %1$S ar %2$S:
+
+# LOCALIZATION NOTE (imapServerNotImap4): Do not translate the word "IMAP4" below.
+imapServerNotImap4=Nid yw'r gweinydd e-bost %S yn weinydd e-bost IMAP4.
+
+# This is intentionally left blank.
+imapDone=
+
+# LOCALIZATION NOTE (imapEnterPasswordPromptTitleWithUsername): Do not translate the
+# word %1$S. Place the word %1$S where the user name should appear.
+imapEnterPasswordPromptTitleWithUsername=Rhowch eich cyfrinair ar gyfer %1$S
+
+imapUnknownHostError=Methwyd cysylltu â gweinydd %S.
+imapOAuth2Error=Methiant dilysu wrth gysylltu â gweinydd %S.
+
+imapConnectionRefusedError=Methu cysylltu â gweinydd e-bost %S; gwrthodwyd y cysylltiad.
+
+imapNetTimeoutError=Cyfnod cyswllt i weinydd %S wedi dod i ben.
+
+imapTlsError=Digwyddodd gwall TLS nad oedd modd ei ddiystyru. Mae gwall ysgwyd llaw neu, yn ôl pob tebyg, y fersiwn neu'r dystysgrif TLS sy'n cael ei ddefnyddio gan weinydd %S yn anghydnaws.
+
+# Status - no messages to download
+imapNoNewMessages=Nid oes negeseuon newydd ar y gweinydd.
+
+imapDefaultAccountName=E-bost ar gyfer %S
+
+imapSpecialChar2=Mae nod %S wedi ei neilltuo ar y gweinydd imap hwn. Dewiswch enw arall. 
+
+imapPersonalSharedFolderTypeName=Ffolder Personol
+
+imapPublicFolderTypeName=Ffolder Cyhoeddus
+
+imapOtherUsersFolderTypeName=Ffolder Defnyddiwr Arall
+
+imapPersonalFolderTypeDescription=Ffolder e-bost personol.  Nid yw'n cael ei rhannu.
+
+imapPersonalSharedFolderTypeDescription=Ffolder e-bost personol yw hwn.  Mae,n cael ei rhannu.
+
+imapPublicFolderTypeDescription=Ffolder cyhoeddus yw hwn.
+
+imapOtherUsersFolderTypeDescription=Mae hwn yn ffolder e-bost sy'n cael ei rannu gan ddefnyddiwr '%S'.
+
+imapAclFullRights=Rheolaeth Lawn
+
+imapAclLookupRight=Chwilio
+
+imapAclReadRight=Darllen
+
+imapAclSeenRight=Gosod Cyflwr Darllen/Heb ei Ddarllen
+
+imapAclWriteRight=Ysgrifennu
+
+imapAclInsertRight=Mewnosod (Copïo i)
+
+imapAclPostRight=Cofnodi
+
+imapAclCreateRight=Creu Is-ffolder
+
+imapAclDeleteRight=Dileu Negeseuon
+
+imapAclAdministerRight=Gweinyddu Ffolder
+
+imapServerDoesntSupportAcl=Nid yw'r gweinydd yn cynnal ffolderi wedi'u rhannu.
+
+imapAclExpungeRight=Dileu
+
+imapServerDisconnected= Mae gweinydd %S wedi datgysylltu. Efallai bod y gweinydd yn wallus neu fod anhawster gyda'r rhwydwaith.
+
+# LOCALIZATION NOTE (autoSubscribeText): %1$S is the imap folder.
+imapSubscribePrompt=Hoffech chi danysgrifio i %1$S?
+
+imapServerDroppedConnection=Methu cysylltu â'ch gweinydd IMAP. Efallai eich bod wedi mynd dros yr uchafswm o gysylltiadau âr gweinydd hwn. Os felly, defnyddiwch ddeialog Gosodiadau Gweinydd IMAP Uwch i leihau'r nifer o gysylltiadau storiwyd.
+
+# This will occur when a folder that has never been imap selected or opened
+# (left-clicked) is first right-clicked to access quota properties.
+imapQuotaStatusFolderNotOpen=Nid oes gwybodaeth cwota ar gael am nad yw'r ffolder ar agor.
+
+# The imap capability response reports that QUOTA is not supported.
+imapQuotaStatusNotSupported=Nid yw'r gweinydd yn cynnal cwotâu.
+
+# The getqutaroot command succeeded but reported no quota information.
+imapQuotaStatusNoQuota2=Nid yw'r ffolder hon yn adrodd am unrhyw wybodaeth gwota.
+
+# Folder properties were requested by the user (right-click) before the getquotaroot
+# command was sent.
+imapQuotaStatusInProgress=Nid yw gwybodaeth gwota ar gael eto.
+
+# Out of memory
+imapOutOfMemory=Dim cof ar ôl gan y rhaglen.
+
+# LOCALIZATION NOTE (imapCopyingMessageOf2): Do not translate the word "%S" below.
+# Place the word %3$S in your translation where the name of the destination folder should appear.
+# Place the word %1$S where the currently copying message should appear.
+# Place the word %2$S where the total number of messages should appear.
+imapCopyingMessageOf2=Copïo neges %1$S o %2$S i %3$S…
+
+# LOCALIZATION NOTE (imapMoveFolderToTrash): Do not translate the word %S below.
+# "%S" is the the name of the folder.
+imapMoveFolderToTrash=Ydych chi'n siŵr eich bod am ddileu ffolder '%S'?
+
+# LOCALIZATION NOTE (imapDeleteNoTrash): Do not translate the word %S below.
+# "%S" is the the name of the folder.
+imapDeleteNoTrash=Nid yw dileu'r ffolder hwn yn annileadwy a bydd yn dileu'r holl negeseuon sydd o'i fewn a'r is-ffolderi. Ydych chi'n siŵr eich bod am ddileu ffolder '%S'?
+
+imapDeleteFolderDialogTitle=Dileu Ffolder
+
+imapDeleteFolderButtonLabel=&Dileu Ffolder
+
+# LOCALIZATION NOTE (imapAuthChangeEncryptToPlainSSL): %S is the server hostname
+imapAuthChangeEncryptToPlainSSL=Nid yw gweinydd IMAP %S i weld yn cynnal cyfrineiriau wedi eu hamgryptio. Os ydych newydd osod y cyfrif, ceisiwch newid i 'Cyfrinair arferol' fel y 'Dull Dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau Gweinydd'. Os oedd arfer a gweithio a nawr yn methu'n sydyn, cysylltwch â'ch gweinyddwr e-bost neu eich darparwr.
+
+# LOCALIZATION NOTE (imapAuthChangePlainToEncrypt): %S is the server hostname
+imapAuthChangePlainToEncrypt=Nid yw gweinydd IMAP %S yn caniatáu cyfrineiriau testun plaen. Ceisiwch newid i 'Cyfrinair wedi ei hamgryptio' fel y 'Dull Dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'.
+
+# LOCALIZATION NOTE (imapAuthChangeEncryptToPlainNoSSL): %S is the server hostname
+imapAuthChangeEncryptToPlainNoSSL=Nid yw gweinydd IMAP %S i weld yn cynnal cyfrineiriau wedi'u hamgryptio. Os ydych newydd osod y cyfrif, ceisiwch newid i 'Cyfrinair, trosglwyddo'n anniogel' fel y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'. Os oedd arfer gweithio a nawr yn methu'n sydyn, cysylltwch â'ch gweinyddwr e-bost neu eich darparwr.
+
+# LOCALIZATION NOTE (imapAuthMechNotSupported): %S is the server hostname
+imapAuthMechNotSupported=Nid yw gweinydd IMAP %S yn cynnal y dull dilysu yma. Newidiwch y 'Dull Dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'.
+
+# LOCALIZATION NOTE (imapAuthGssapiFailed): %S is the server hostname
+imapAuthGssapiFailed=Nid yw'r tocyn Kerberos/GSSAPI wedi'i dderbyn gan y gweinydd IMAP %S. Gwiriwch eich bod wedi mewngofnodi i gylch Kerberos/GSSAPI.
+
+# LOCALIZATION NOTE (imapServerCommandFailed):
+# Place the word %1$S in your translation where the name of the account name should appear.
+# Place the word %2$S in your translation where the server response should appear.
+imapServerCommandFailed=Nid yw'r gorchymyn cyfredol wedi llwyddo. Ymateb gweinydd e-bost cyfrif %1$S oedd: %2$S\u0020
+
+# LOCALIZATION NOTE (imapFolderCommandFailed): Do not translate the word %S below.
+# Place the word %1$S in your translation where the name of the account should appear.
+# Place the word %2$S in your translation where the name of the folder should appear.
+# Place the word %3$S in your translation where the server response should appear.
+imapFolderCommandFailed=Nid oedd y weithred gyfredol ar '%2$S' yn llwyddiant. Ymateb gweinydd e-bost cyfrif %1$S oedd: %3$S
+
+# LOCALIZATION NOTE (imapServerAlert):
+# Place the word %1$S in your translation where the name of the account should appear.
+# Place the word %2$S in your translation where the alert from the server should appear.
+imapServerAlert=Rhybudd o gyfrif %1$S: %2$S
diff --git a/l10n-cy/mail/chrome/messenger/importDialog.dtd b/l10n-cy/mail/chrome/messenger/importDialog.dtd
new file mode 100644
index 0000000000..602cdb43e6
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/importDialog.dtd
@@ -0,0 +1,59 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!--
+LOCALIZATION NOTE : 'Communicator 4.x' is the used for previous versions of 
+Netscape Communicator, Please translate using the brandname in respective 
+languages for Netscape Communicator 4 releases.
+LOCALIZATION NOTE : Do not translate any of the occurrences of the word 
+"&brandShortName;" below.
+-->
+
+
+<!--
+LOCALIZATION NOTE : 'Communicator 4.x' is the used for previous versions of
+Netscape Communicator, Please translate using the brandname in respective
+languages for Netscape Communicator 4 releases.
+LOCALIZATION NOTE : Do not translate any of the occurrences of the word
+"&brandShortName;" below.
+-->
+
+<!ENTITY importDialog.windowTitle "Mewnforio">
+<!ENTITY importAll.label          "Mewnforio Popeth">
+<!ENTITY importAll.accesskey      "P">
+<!ENTITY importMail.label         "E-bost">
+<!ENTITY importMail.accesskey     "E">
+<!ENTITY importFeeds.label        "Tanysgrifiad Llif">
+<!ENTITY importFeeds.accesskey    "T">
+<!ENTITY importAddressbook.label  "Llyfrau Cyfeiriadau">
+<!ENTITY importAddressbook.accesskey "L">
+<!ENTITY importSettings.label     "Gosodiadau">
+<!ENTITY importSettings.accesskey "G">
+<!ENTITY importFilters.label      "Hidlau">
+<!ENTITY importFilters.accesskey  "H">
+
+<!ENTITY  window.width            "40em">
+<!ENTITY  window.macWidth         "45em">
+
+<!ENTITY importTitle.label        "Dewin Mewnforio E-bost &brandShortName;">
+<!ENTITY importShortDesc.label    "Mewnforio E-bost a Llyfrau Cyfeiriadau, Gosodiadau a Hidlau o raglenni eraill">
+
+<!ENTITY importDescription1.label "Bydd y dewin yn mewnforio negeseuon e-bost, dewisiadau cofnodion llyfrau cyfeiriadau a/neu hidlau o raglenni e-bost eraill ac ar fformat llyfr cyfeiriadau cyffredin i mewn i &brandShortName;.">
+<!ENTITY importDescription2.label "Unwaith y byddant wedi'u mewnforio bydd modd cael mynediad iddynt o fewn &brandShortName;.">
+
+<!ENTITY selectDescription.label  "Dewiswch y math o ffeil i'w mewnforio:">
+<!ENTITY selectDescriptionB.label "Dewiswch gyfrif cyfredol neu greu cyfrif newydd:">
+<!ENTITY selectDescription.accesskey "f">
+<!ENTITY acctName.label           "Enw:">
+<!ENTITY acctName.accesskey       "E">
+<!ENTITY noModulesFound.label     "Dim rhaglen na ffeil i fewnforio data ohoni wedi ei ganfod.">
+
+<!ENTITY back.label               "&lt; Nôl">
+<!ENTITY forward.label            "Nesaf &gt;">
+<!ENTITY finish.label             "Gorffen">
+<!ENTITY cancel.label             "Diddymu">
+
+<!ENTITY select.label             "neu ddewis y math o ddeunydd i'w fewnforio:">
+
+<!ENTITY title.label              "Teitl">
+<!ENTITY processing.label         "Mewnforio…">
diff --git a/l10n-cy/mail/chrome/messenger/importMsgs.properties b/l10n-cy/mail/chrome/messenger/importMsgs.properties
new file mode 100644
index 0000000000..ab7c517e95
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/importMsgs.properties
@@ -0,0 +1,307 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The following are used by the import code to display status/error 
+# and informational messages
+
+# The following are used by the import code to display status/error
+# and informational messages
+
+# Success message when no address books are found to import
+## @name IMPORT_NO_ADDRBOOKS
+## @loc None
+2000=Heb ganfod llyfrau cyfeiriadau i'w mewnforio.
+
+# Error: Address book import not intialized		
+## @name IMPORT_ERROR_AB_NOTINITIALIZED
+## @loc None
+2001=Methu mewnforio llyfrau cyfeiriadau: gwall ymgychwyn.
+
+# Error: Unable to create the import thread
+## @name IMPORT_ERROR_AB_NOTHREAD
+## @loc None
+2002=Methu mewnforio llyfrau cyfeiriadau: methu creu edefyn mewnforio.
+
+# Error: Unable to create the import thread
+## @name IMPORT_ERROR_GETABOOK
+## @loc None
+# LOCALIZATION NOTE (Error 2003): Do not translate the word "%S" below.
+2003=Gwall wrth fewnforio %S: methu creu llyfr cyfeiriadau.
+
+# Success message when no mailboxes are found to import
+## @name IMPORT_NO_MAILBOXES
+## @loc None
+2004=Dim blychau e-bost wediu canfod i'w mewnforio
+
+# Error: Mailbox import not intialized		
+## @name IMPORT_ERROR_MB_NOTINITIALIZED
+## @loc None
+2005=Methu mewnforio blychau e-bost, gwall ymgychwyn
+
+# Error: Unable to create the import thread
+## @name IMPORT_ERROR_MB_NOTHREAD
+## @loc None
+2006=Methu mewnforio blychau e-bost, methu creu edefyn mewnforio
+
+# Error: Unable to create the proxy object for importing mailboxes
+## @name IMPORT_ERROR_MB_NOPROXY
+## @loc None
+2007=Methu mewnforio blychau e-bost, methu creu gwrthrych dirprwyol ar gyfer cyrchfan blychau e-bost
+
+# Error: Error creating destination mailboxes
+## @name IMPORT_ERROR_MB_FINDCHILD
+## @loc None
+# LOCALIZATION NOTE (Error 2008): Do not translate the word "%S" below.
+# Place %S in your translation where the name of the mailbox should appear.
+2008=Gwall wrth greu blychau e-bost cyrchfan, methu canfod blwch %S
+
+# Error: Error creating destination mailboxes
+## @name IMPORT_ERROR_MB_CREATE
+## @loc None
+# LOCALIZATION NOTE (Error 2009): Do not translate the word "%S" below.
+# Place %S in your translation where the name of the mailbox should appear.
+2009=Gwall wrth fewnforio blwch e-bost %S, methu creu blwch e-bost cyrchfan
+
+# Error: No destination folder to import mailboxes
+## @name IMPORT_ERROR_MB_NODESTFOLDER
+## @loc None
+2010=Methu creu cyfrif i fewnforio iddo
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC_START
+## @loc None
+2100=Enw Cyntaf
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2101=Enw Olaf
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2102=Enw Dangos
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2103=Llysenw
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2104=Prif E-bost
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2105=E-bost Eilradd
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2106=Rhif Ffôn Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2107=Rhif Ffôn Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2108=Rhif Ffacs
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2109=Rhif Swnyn
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2110=Rhif Ffôn Symudol
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2111=Cyfeiriad Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2112=Cyfeiriad Cartref 2
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2113=Tref/Dinas Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2114=Sir/Talaith Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2115=Cod Post Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2116=Gwlad Cartref
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2117=Cyfeiriad Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2118=Cyfeiriad Gwaith 2
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2119=Tref/Dinas Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2120=Sir/Talaith Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2121=Cod Post Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2122=Gwlad Gwaith
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2123=Teitl Swydd
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2124=Adran
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2125=Corff
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2126=Tudalen Gwe 1
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2127=Tudalen Gwe 2
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2128=Blwyddyn Geni
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2129=Mis Geni
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2130=Diwrnod Geni
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2131=Cyfaddasu 1
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2132=Cyfaddasu 2
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2133=Cyfaddasu 3
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2134=Cyfaddasu 4
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC
+## @loc None
+2135=Nodiadau
+
+# Description: Address book field name
+## @name IMPORT_FIELD_DESC_END
+## @loc None
+2136=Enw Sgrin
+
+#Error strings
+ImportAlreadyInProgress=Mae gweithred mewnforio yn digwydd ar hyn o bryd, rhowch gynnig arall pan fydd y mewnforio cyfredol wedi dod i ben.
+
+#Error strings for settings import
+ImportSettingsBadModule=Methu llwytho modiwl gosodiadau
+ImportSettingsNotFound=Methu canfod gosodiadau.  Gwiriwch fod y rhaglen wedi'i osod ar y peiriant.
+ImportSettingsFailed=Digwyddodd gwall wrth fewnforio gosodiadau.  Mae'n bosib i rai ac efallai'r cyfan fethu cael eu mewnforio.
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+ImportSettingsSuccess=Gosodiadau wedi'u mewnforio o %S
+
+#Error string for mail import
+ImportMailBadModule=Methu llwytho modiwl mewnforio e-bost
+ImportMailNotFound=Digwyddodd gwall wrth fewnforio gosodiadau.  Mae'n bosib i rai ac efallai'r cyfan fethu cael eu mewnforio.
+ImportEmptyAddressBook=Methu mewnforio llyfr cyfeiriadau gwag %S.
+# LOCALIZATION NOTE: Do not translate the word "%S" below.
+ImportMailFailed=Digwyddodd gwall wrth fewnforio e-bost o %S
+# LOCALIZATION NOTE: Do not translate the word "%S" below.
+ImportMailSuccess=E-bost wedi'i fewnforio'n llwyddiannus o %S
+
+# Error string for address import
+ImportAddressBadModule=Methu llwytho modiwl mewnforio llyfr cyfeiriadau.
+ImportAddressNotFound=Methu canfod unrhyw lyfr cyfeiriadau i'w fewnforio.  Gwiriwch fod y rhaglen neu'r fformat wedi'i osod yn gywir ar y peiriant.
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+ImportAddressFailed=Digwyddodd gwall wrth fewnforio cyfeiriadau o %S.
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+ImportAddressSuccess=Cyfeiriadau wedi'u mewnforio'n llwyddiannus o %S.
+
+# Error string for filters import
+ImportFiltersBadModule=Methu llwytho modiwl mewnforio hidlau.
+# LOCALIZATION NOTE : The %S will get replaced by the name of the import module.
+ImportFiltersFailed=Digwyddodd gwall wrth fewnforio hidlau o %S.
+# LOCALIZATION NOTE : The %S will get replaced by the name of the import module.
+ImportFiltersSuccess=Hidlau wedi'u mewnforio'n llwyddiannus o %S.
+# LOCALIZATION NOTE : The %S will get replaced by the name of the import module.
+ImportFiltersPartial=Hidlau wedi'u mewnforio'n rhannol o %S.  Rhybudd isod:
+
+#Progress strings
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+MailProgressMeterText=Trosi blychau e-bost o %S
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+AddrProgressMeterText=Trosi llyfrau cyfeiriadau o %S
+
+#Import file dialog strings
+ImportSelectSettings=Dewiswch ffeil gosodiadau
+ImportSelectMailDir=Dewiswch gyfeiriadur e-bost
+ImportSelectAddrDir=Dewiswch gyfeiriadur llyfr cyfeiriadau
+ImportSelectAddrFile=Dewiswch ffeil llyfr cyfeiriadau
+
+# Folder Names for imported Mail
+DefaultFolderName=E-bost wedi'i Fewnforio
+# LOCALIZATION NOTE: Do not translate the word "%S" below.
+ImportModuleFolderName=Mewnforio %S
diff --git a/l10n-cy/mail/chrome/messenger/joinChat.dtd b/l10n-cy/mail/chrome/messenger/joinChat.dtd
new file mode 100644
index 0000000000..ff1971209f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/joinChat.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY joinChatWindow.title           "Ymuno â sgwrs">
+<!ENTITY name.label                     "Ystafell">
+<!ENTITY optional.label                 "(dewisol)">
+<!ENTITY account.label                  "Cyfrif">
+<!ENTITY autojoin.label                 "Awto-ymuno â'r Ystafell Sgwrsio">
+<!ENTITY autojoin.accesskey             "A">
diff --git a/l10n-cy/mail/chrome/messenger/junkLog.dtd b/l10n-cy/mail/chrome/messenger/junkLog.dtd
new file mode 100644
index 0000000000..96e6d35a7c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/junkLog.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY adaptiveJunkLog.title "Cofnod Sbam Addasol">
+<!ENTITY adaptiveJunkLogInfo.label "Cofnod gweithgaredd rheoli e-bost sbam addasol.">
+<!ENTITY clearLog.label "Clirio'r Cofnod">
+<!ENTITY clearLog.accesskey "l">
+<!ENTITY closeLog.label "Cau">
+<!ENTITY closeLog.accesskey "a">
diff --git a/l10n-cy/mail/chrome/messenger/junkMailInfo.dtd b/l10n-cy/mail/chrome/messenger/junkMailInfo.dtd
new file mode 100644
index 0000000000..86775300d9
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/junkMailInfo.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title  "Ynghylch E-bost Sbam">
+<!ENTITY window.width  "450">
+<!ENTITY info1a.label  "Mae &brandShortName; yn canfod negeseuon sy'n ymddangos eu bod yn e-bost sbam yn awtomatig. Bydd negeseuon mae &brandShortName; yn meddwl eu bod yn sbam yn cael eu dangos gydag eicon e-bost sbam">
+<!ENTITY info1b.label  ".">
+<!ENTITY info2.label   "Ar y cychwyn, rhaid hyfforddi &brandShortName; i adnabod sbam drwy'r botwm bar Sbam i farcio neges yn e-bost sbam neu beidio.">
+<!ENTITY info3.label   "Unwaith mae &brandShortName; yn adnabod sbam yn gyson, bydd modd i chi ddefnyddio'r Rheolyddion Sbam y awtomatig i symud sbam i'r ffolder Sbam.">
+<!ENTITY info4.label   "Am ragor o wybodaeth, cliciwch Cymorth.">
diff --git a/l10n-cy/mail/chrome/messenger/localMsgs.properties b/l10n-cy/mail/chrome/messenger/localMsgs.properties
new file mode 100644
index 0000000000..f22bda2951
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/localMsgs.properties
@@ -0,0 +1,149 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the local mail code to display progress/status/error messages
+#
+
+# LOCALIZATION NOTE(pop3ErrorDialogTitle): Do not translate the word "%S"
+# below. Place the word %S where the account name should appear.
+pop3ErrorDialogTitle=Gwall gyda chyfrif %S
+
+# LOCALIZATION NOTE (pop3EnterPasswordPromptTitleWithUsername): Do not translate the
+# word %1$S. Place the word %1$S where the user name should appear.
+pop3EnterPasswordPromptTitleWithUsername=Rhowch eich cyfrinair ar gyfer %1$S
+
+# LOCALIZATION NOTE(pop3EnterPasswordPrompt): Do not translate the words "%1$S"
+# and "%2$S" below. Place the word %1$S where the user name should appear, and
+# %2$S where the host name should appear.
+pop3EnterPasswordPrompt=Cyflwyno eich cyfrinair ar gyfer %1$S ar %2$S:
+
+# LOCALIZATION NOTE(pop3PreviouslyEnteredPasswordIsInvalidPrompt): Do not
+# translate the words "%1$S" and "%2$S" below. Place the word %1$S where the
+# user name should appear, and %2$S where the host name should appear.
+pop3PreviouslyEnteredPasswordIsInvalidPrompt=Rhoi cyfrinair newydd i ddefnyddiwr %1$S ar %2$S:
+
+# Status - Downloading message n of m
+# LOCALIZATION NOTE (receivingMessages): Do not translate %1$S or %2$S in the following lines.
+# Place the word %1$S where the number of messages downloaded so far should appear.
+# Place the word %2$S where the total number of messages to receive should appear;
+receivingMessages=Llwytho i lawr neges %1$S o %2$S…
+
+# Status - connecting to host
+hostContact=Wedi cysylltu â'r gwesteiwr, anfon manylion mewngofnodi…
+
+# Status - no messages to download
+noNewMessages=Does dim negeseuon newydd.
+
+# Status - messages received after the download
+#LOCALIZATION NOTE : Do not translate %1$S or %2$S in the following line.
+# %1$S will receive the number of messages received
+# %2$S will receive the total number of messages
+receivedMsgs=Mae %1$S o %2$S neges wedi eu derbyn
+
+# Status - parsing folder
+#LOCALIZATION NOTE (buildingSummary): Do not translate %S in the following line.
+# Place the word %S where the name of the mailbox should appear
+buildingSummary=Adeiladu ffeil crynodeb ar gyfer %S…
+
+# Status - parsing folder
+localStatusDocumentDone=Gorffen
+
+# Status - pop3 server error
+#LOCALIZATION NOTE (pop3ServerError): Do not translate POP3 in the following line.
+pop3ServerError=Digwyddodd gwall gyda gweinydd e-bost POP3.
+
+# Status - pop3 user name failed
+pop3UsernameFailure=Methwyd anfon yr enw defnyddiwr.
+
+# Status - password failed
+#LOCALIZATION NOTE (pop3PasswordFailed): Do not translate "%1$S" below.
+# Place the word %1$S where the user name should appear.
+pop3PasswordFailed=Methodd anfon cyfrinair defnyddiwr %1$S.
+
+# Status - write error occurred
+pop3MessageWriteError=Methu ysgrifennu'r e-bost i'r blwch e-bost. Gwnewch yn siŵr fod y system ffeiliau yn caniatáu hawliau ysgrifennu a bod gennych ddigon o le ar ddisg i gopïo i'r blwch e-bost.
+
+# Status - retr failure from the server
+pop3RetrFailure=Methodd y gorchymyn RETR. Gwall estyn y neges.
+
+# Status - password undefined
+pop3PasswordUndefined=Gwall wrth estyn cyfrinair e-bost.
+
+# Status - username undefined
+pop3UsernameUndefined=Nid ydych wedi darparu enw defnyddiwr ar gyfer y gweinydd.  Darparwch un yn newislen gosod y cyfrif a cheisio eto.
+
+# Status - list failure
+pop3ListFailure=Methodd y gorchymyn LIST. Gwall canfod enw a maint y neges.
+
+# Status - delete error
+pop3DeleFailure=Methodd y gorchymyn DELE. Gwall wrth farcio neges wedi'i ddileu.
+
+# Status - stat failed
+pop3StatFail=Methodd y gorchymyn STAT. Gwall canfod rhif y neges a'u maint.
+
+#LOCALIZATION NOTE (pop3ServerSaid): Do not remove the leading space during translation.
+pop3ServerSaid= Ymateb gweinydd e-bost %S oedd:\u0020
+
+copyingMessagesStatus=Copïo %S o %S neges i %S
+
+movingMessagesStatus=Symud %S o %S neges i %S
+
+# Status - pop3 server or folder busy
+# LOCALIZATION NOTE (pop3ServerBusy): Do not translate the word "%S" below.
+# Place %S where the account name should appear.
+pop3ServerBusy=Mae cyfrif %S yn cael ei brosesu. Arhoswch i'r prosesu gwblhau cyn derbyn eich negeseuon.
+
+movemailCantOpenSpoolFile=Methu agos ffeil sbwlio e-bost %S.
+
+movemailCantCreateLock=Methu creu ffeil cloi %S. I movemail weithio, rhaid creu ffeiliau cloi yng nghyfeiriadur sbwlio e-bost. Ar lawer o systemau, mae'n well gwneud hyn drwy osod y cyfeiriadur sbwlio ym modd 01777.
+
+movemailCantDeleteLock=Methu dileu ffeil cloi %S.
+
+movemailCantTruncateSpoolFile=Methu tocio ffeil sbwlio %S.
+
+movemailSpoolFileNotFound=Methu canfod ffeil sbwlio e-bost.
+
+#LOCALIZATION NOTE (movemailCantParseSpool): %S is file name
+movemailCantParseSpool=Methu didoli ffeil spwlio %S. Efallai fod y ffeil yn annilys neu llwgr.
+
+pop3TmpDownloadError=Bu gwall wrth lwytho i lawr y neges ganlynol:   \nOddi wrth: %S\n   Pwnc: %S\n Gall y neges gynnwys firws neu does dim digon o le ar y disg. Hepgor y neges?
+
+# Status - the server doesn't support UIDL…
+# LOCALIZATION NOTE(pop3ServerDoesNotSupportUidlEtc): The following sentence should be translated in this way:
+# Do not translate "POP3"
+# Do not translate "%S". Place %S in your translation where the name of the server should appear.
+# Do not translate "UIDL"
+pop3ServerDoesNotSupportUidlEtc=Nid yw'r gweinydd POP3 (%S) yn cynnal UIDL na XTND XLST, sydd ei angen i weithredu dewisiadau ``Gadael ar y Gweinydd", ``Maint Mwyaf Neges" neu ``Estyn Pennyn yn Unig". I lwytho eich e-bost i lawr diffoddwch y dewisiadau hyn Gosodiadau Gweinydd eich gweinydd e-bost yn ffenestr Gosodiadau Cyfrif.
+
+# Status - the server doesn't support the top command
+# LOCALIZATION NOTE(pop3ServerDoesNotSupportTopCommand): The following sentence should be translated in this way:
+# Do not translate "POP3"
+# Do not translate "%S". Place %S in your translation where the name of the server should appear.
+# Do not translate "TOP"
+pop3ServerDoesNotSupportTopCommand=Nid yw'r gweinydd POP3 (%S) yn cynnal y gorchymyn TOP. Heb gefnogaeth y gweinydd ar gyfer hwn nid ydym yn gallu gweithredu dewisiadau ``Maint Mwyaf Neges" neu ``Estyn Pennyn yn Unig".  Mae'r dewis wedi ei anablu a bydd negeseuon yn cael eu llwytho i lawr beth bynnag yw eu maint.
+
+nsErrorCouldNotConnectViaTls=Methu creu cysylltiad TLS gyda gweinydd POP3. Gall fod bod y gweinydd wedi methu neu heb ei ffurfweddu'n gywir. Gwiriwch fod gosodiadau eich cyfrif E-bost/Newyddion yn gywir a cheisiwch eto.
+
+# LOCALIZATION NOTE (pop3MoveFolderToTrash): Do not translate the word %S below.
+# "%S" is the the name of the folder.
+pop3MoveFolderToTrash=Ydych chi'n siŵr eich bod am ddileu'r ffolder '%S'?
+
+pop3DeleteFolderDialogTitle=Dileu Ffolder
+
+pop3DeleteFolderButtonLabel=&Dileu Ffolder
+
+pop3AuthInternalError=Gwall cyflwr mewnol yn ystod dilysu gweinydd POP3. Gwall mewnol annisgwyl o fewn y rhaglen yw hwn, anfonwch adroddiad gwall.
+
+pop3AuthChangeEncryptToPlainNoSSL=Nid yw'r gweinydd e-bost POP3 yma i weld yn cynnal cyfrineiriau amgryptiedig. Os ydych newydd greu cyfrif, ceisiwch hewid i 'Cyfrinair, trosglwyddo anniogel' fel y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'. Os oedd arfer gweithio ond nawr yn methu, mae hwn yn sefyllfa gyffredin lle gall rhywun ddwyn eich cyfrinair.
+
+pop3AuthChangeEncryptToPlainSSL=Nid yw'r gweinydd e-bost POP3 yma i weld yn cynnal cyfrineiriau amgryptiedig. Os ydych newydd greu cyfrif, ceisiwch newid i 'Cyfrinair arferol' fel y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'. Os oedd arfer gweithio ond nawr yn methu, cysylltwch â'ch gweinyddwr e-bost neu ddarparwr.
+
+pop3AuthChangePlainToEncrypt=Nid yw'r gweinydd e-bost POP3 yma caniatáu cyfrineiriau testun plaen. Ceisiwch newid i 'Cyfrinair amgryptiedig' fel y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'.
+
+# Authentication server caps and pref don't match
+pop3AuthMechNotSupported=Nid yw'r gweinydd yn cynnal y dull dilysu yma. Newidiwch y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd'.
+
+# Status - Could not log in to GSSAPI, and it was the only method
+pop3GssapiFailure=Nid yw'r tocyn Kerberos/GSSAPI wedi'i dderbyn gan y gweinydd POP. Gwiriwch eich bod wedi eich mewngofnodi i'r cylch Kerberos/GSSAPI.
diff --git a/l10n-cy/mail/chrome/messenger/mailEditorOverlay.dtd b/l10n-cy/mail/chrome/messenger/mailEditorOverlay.dtd
new file mode 100644
index 0000000000..64728f3361
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mailEditorOverlay.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY sendPage.label                   "Anfon y Dudalen…">
+<!ENTITY sendPage.accesskey               "A">
diff --git a/l10n-cy/mail/chrome/messenger/mailOverlay.dtd b/l10n-cy/mail/chrome/messenger/mailOverlay.dtd
new file mode 100644
index 0000000000..5b7c0eab37
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mailOverlay.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  newMessageCmd2.key              "N">
+<!ENTITY  newMessageCmd.key               "M">
+<!ENTITY  newMessageCmd.label             "Neges">
+<!ENTITY  newMessageCmd.accesskey         "N">
+ 
+<!ENTITY  newContactCmd.label             "Cysylltiad Llyfr Cyfeiriadau…">
+<!ENTITY  newContactCmd.accesskey         "C">
diff --git a/l10n-cy/mail/chrome/messenger/mailViewList.dtd b/l10n-cy/mail/chrome/messenger/mailViewList.dtd
new file mode 100644
index 0000000000..f2f599b051
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mailViewList.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgViewPickerOverlay.dtd UI for showing various views on a folder -->
+
+
+<!ENTITY mailViewListTitle.label "Cyfaddasu Golwg Negeseuon">
+
diff --git a/l10n-cy/mail/chrome/messenger/mailViewSetup.dtd b/l10n-cy/mail/chrome/messenger/mailViewSetup.dtd
new file mode 100644
index 0000000000..49b1a15a8d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mailViewSetup.dtd
@@ -0,0 +1,12 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgViewPickerOverlay.dtd UI for showing various views on a folder -->
+
+
+<!ENTITY mailViewSetupTitle.label "Gosod Golwg Negeseuon">
+<!ENTITY mailViewHeading.label "Enw golwg neges:">
+<!ENTITY mailViewHeading.accesskey "E">
+<!ENTITY searchTermCaption.label "Pan fyddwch yn dewis y golwg hwn, dangos dim ond negeseuon sydd:">
+
diff --git a/l10n-cy/mail/chrome/messenger/mailviews.properties b/l10n-cy/mail/chrome/messenger/mailviews.properties
new file mode 100644
index 0000000000..380ce9ec25
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mailviews.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# Mail Views
+#
+
+mailViewPeopleIKnow=Pobl Rwy'n Nabod
+mailViewRecentMail=E-bost Diweddar
+mailViewLastFiveDays=5 Diwrnod Diwethaf
+mailViewNotJunk=Nid Sbam
+mailViewHasAttachments=Atodiadau Ynghlwm
diff --git a/l10n-cy/mail/chrome/messenger/markByDate.dtd b/l10n-cy/mail/chrome/messenger/markByDate.dtd
new file mode 100644
index 0000000000..6b5772f28e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/markByDate.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY messageMarkByDate.label "Marcio'r Negeseuon Wedi eu Darllen yn ôl Dyddiad">
+<!ENTITY markByDateLower.label "Marcio'r negeseuon hyn wedi'u darllen ers:">
+<!ENTITY markByDateLower.accesskey "M">
+<!ENTITY markByDateUpper.label "At:">
+<!ENTITY markByDateUpper.accesskey "A">
diff --git a/l10n-cy/mail/chrome/messenger/messenger.dtd b/l10n-cy/mail/chrome/messenger/messenger.dtd
new file mode 100644
index 0000000000..be0111c2c5
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messenger.dtd
@@ -0,0 +1,973 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY titledefault.label "&brandFullName;">
+<!ENTITY titleSeparator.label " - ">
+
+<!-- File Menu -->
+<!ENTITY newFolderCmd.label "Ffolder…">
+<!ENTITY newFolderCmd.accesskey "F">
+<!ENTITY closeTabCmd2.label "Cau'r Tab">
+<!ENTITY closeTabCmd2.accesskey "C">
+<!ENTITY closeOtherTabsCmd2.label "Cau Tabiau Eraill">
+<!ENTITY closeOtherTabsCmd2.accesskey "E">
+<!ENTITY recentlyClosedTabsCmd.label "Tabiau Wedi'u Cau'n Ddiweddar">
+<!ENTITY recentlyClosedTabsCmd.accesskey "D">
+
+<!ENTITY undoCloseTabCmd.commandkey "T">
+<!-- LOCALIZATION NOTE (moveToNewWindow.label):
+     Menu option to cause the current tab to be migrated to a new Thunderbird
+     window.
+     -->
+<!ENTITY moveToNewWindow.label "Symud i Ffenestr Newydd">
+<!ENTITY moveToNewWindow.accesskey "S">
+<!ENTITY newVirtualFolderCmd.label "Chwilio a Gadwyd…">
+<!ENTITY newVirtualFolderCmd.accesskey "w">
+<!ENTITY newOtherAccountsCmd.label "Cyfrifon Eraill…">
+<!ENTITY newOtherAccountsCmd.accesskey "y">
+<!ENTITY newCreateEmailAccountCmd.label "Estyn Cyfrif E-bost Newydd…">
+<!ENTITY newCreateEmailAccountCmd.accesskey "E">
+<!ENTITY newExistingEmailAccountCmd.label "Cyfrif E-bost Cyfredol…">
+<!ENTITY newExistingEmailAccountCmd.accesskey "C">
+<!ENTITY newIMAccountCmd.label "Cyfrif Sgwrsio…">
+<!ENTITY newIMAccountCmd.accesskey "S">
+<!ENTITY newFeedAccountCmd.label "Cyfrif Llif…">
+<!ENTITY newFeedAccountCmd.accesskey "y">
+<!ENTITY newIMContactCmd.label "Cysylltiad Sgwrsio…">
+<!ENTITY newIMContactCmd.accesskey "S">
+<!ENTITY  newMessageCmd2.key "E">
+<!ENTITY  newMessageCmd.key "N">
+<!ENTITY  newMessageCmd.label "Neges">
+<!ENTITY  newMessageCmd.accesskey "n">
+<!ENTITY  newContactCmd.label "Cysylltiad Llyfr Cyfeiriadau…">
+<!ENTITY  newContactCmd.accesskey "C">
+<!ENTITY openMenuCmd.label "Agor">
+<!ENTITY openMenuCmd.accesskey "A">
+<!ENTITY openMessageFileCmd.label "Agor Neges Wedi'i Chadw…">
+<!ENTITY openMessageFileCmd.accesskey "s">
+<!ENTITY saveAsMenu.label "Cadw Fel">
+<!ENTITY saveAsMenu.accesskey "C">
+<!ENTITY saveAsFileCmd.label "Ffeil">
+<!ENTITY saveAsFileCmd.accesskey "F">
+<!ENTITY saveAsFileCmd.key "s">
+<!ENTITY saveAsTemplateCmd.label "Templed">
+<!ENTITY saveAsTemplateCmd.accesskey "T">
+<!ENTITY getNewMsgForCmd.label "Estyn Negeseuon Newydd">
+<!ENTITY getNewMsgForCmd.accesskey "E">
+<!ENTITY getAllNewMsgCmdPopupMenu.label "Pob Cyfrif">
+<!ENTITY getAllNewMsgCmdPopupMenu.accesskey "P">
+<!ENTITY getNewMsgCurrentAccountCmdPopupMenu.label "Cyfrif Cyfredol">
+<!ENTITY getNewMsgCurrentAccountCmdPopupMenu.accesskey "y">
+<!ENTITY getNextNMsgCmd2.label "Estyn y Negeseuon Newyddion Nesaf">
+<!ENTITY getNextNMsgCmd2.accesskey "E">
+<!ENTITY sendUnsentCmd.label "Anfon Negeseuon heb eu Hanfon">
+<!ENTITY sendUnsentCmd.accesskey "H">
+<!ENTITY subscribeCmd.label "Tanysgrifio…">
+<!ENTITY subscribeCmd.accesskey "T">
+<!ENTITY deleteFolder.label "Dileu Ffolder">
+<!ENTITY deleteFolder.accesskey "D">
+<!ENTITY renameFolder.label "Ailenwi Ffolder…">
+<!ENTITY renameFolder.accesskey "F">
+<!ENTITY renameFolder.key "VK_F2">
+<!ENTITY compactFolders.label "Cywasgu'r Ffolderi">
+<!ENTITY compactFolders.accesskey "w">
+<!ENTITY emptyTrashCmd.label "Gwagio'r Sbwriel">
+<!ENTITY emptyTrashCmd.accesskey "w">
+<!ENTITY offlineMenu.label "All-lein">
+<!ENTITY offlineMenu.accesskey "l">
+<!ENTITY offlineGoOfflineCmd.label "Gweithio All-lein">
+<!ENTITY offlineGoOfflineCmd.accesskey "w">
+<!ENTITY synchronizeOfflineCmd.label "Llwytho i Lawr/Cydweddu Nawr…">
+<!ENTITY synchronizeOfflineCmd.accesskey "L">
+<!ENTITY settingsOfflineCmd2.label "Gosodiadau All-lein">
+<!ENTITY settingsOfflineCmd2.accesskey "G">
+<!ENTITY downloadSelectedCmd.label "Estyn y Negeseuon Hyn">
+<!ENTITY downloadSelectedCmd.accesskey "H">
+<!ENTITY downloadStarredCmd.label "Estyn Negeseuon Serennog">
+<!ENTITY downloadStarredCmd.accesskey "S">
+<!ENTITY printCmd.label "Argraffu…">
+<!ENTITY printCmd.accesskey "A">
+<!ENTITY printCmd.key "p">
+<!ENTITY printPreviewCmd.label "Rhagolwg Argraffu">
+<!ENTITY printPreviewCmd.accesskey "R">
+<!ENTITY printSetupCmd.label "Gosodiad Tudalen…">
+<!ENTITY printSetupCmd.accesskey "o">
+
+<!-- Edit Menu -->
+<!ENTITY deleteMsgCmd.label "Dileu Neges">
+<!ENTITY deleteMsgCmd.accesskey "N">
+<!ENTITY undeleteMsgCmd.label "Dad-ddileu Neges">
+<!ENTITY undeleteMsgCmd.accesskey "a">
+<!ENTITY deleteMsgsCmd.label "Dileu'r Negeseuon Hyn">
+<!ENTITY deleteMsgsCmd.accesskey "i">
+<!ENTITY undeleteMsgsCmd.label "Dad-ddileu'r Negeseuon Hyn">
+<!ENTITY undeleteMsgsCmd.accesskey "a">
+<!ENTITY deleteFolderCmd.label "Dileu Ffolder">
+<!ENTITY deleteFolderCmd.accesskey "F">
+<!ENTITY unsubscribeNewsgroupCmd.label "Dad-danysgrifio">
+<!ENTITY unsubscribeNewsgroupCmd.accesskey "y">
+<!ENTITY selectMenu.label "Dewis">
+<!ENTITY selectMenu.accesskey "w">
+<!ENTITY all.label "Popeth">
+<!ENTITY all.accesskey "P">
+<!ENTITY selectThreadCmd.label "Edefyn">
+<!ENTITY selectThreadCmd.accesskey "E">
+<!ENTITY selectThreadCmd.key "a">
+<!ENTITY selectFlaggedCmd.label "Negeseuon Serennog">
+<!ENTITY selectFlaggedCmd.accesskey "S">
+<!ENTITY menuFavoriteFolder.label "Hoff Ffolder">
+<!ENTITY menuFavoriteFolder.accesskey "H">
+<!ENTITY folderPropsCmd2.label "Priodweddau">
+<!ENTITY folderPropsFolderCmd2.label "Priodweddau Ffolder">
+<!ENTITY folderPropsNewsgroupCmd2.label "Priodweddau Grŵp Newyddion">
+<!ENTITY folderPropsCmd.accesskey "o">
+<!ENTITY undoDeleteMsgCmd.label "Dadwneud Dileu Negeseuon">
+<!ENTITY redoDeleteMsgCmd.label "Ail-wneud Dileu Neges">
+<!ENTITY undoMoveMsgCmd.label "Dadwneud Symud Neges">
+<!ENTITY redoMoveMsgCmd.label "Ailwneud Symud Neges">
+<!ENTITY undoCopyMsgCmd.label "Dadwneud Copïo Neges">
+<!ENTITY redoCopyMsgCmd.label "Ail-wneud Copïo Neges">
+<!ENTITY undoMarkAllCmd.label "Dadwneud Marcio Pob Un Wedi ei Ddarllen">
+<!ENTITY redoMarkAllCmd.label "Ail-wneud Marcio Popeth Wedi'i Ddarllen">
+<!ENTITY undoDefaultCmd.label "Dadwneud">
+<!ENTITY undoDefaultCmd.accesskey "u">
+<!ENTITY redoDefaultCmd.label "Ailwneud">
+<!ENTITY redoDefaultCmd.accesskey "A">
+
+<!-- View Menu -->
+<!ENTITY menubarCmd.label "Bar Dewislen">
+<!ENTITY menubarCmd.accesskey "D">
+<!ENTITY showMessengerToolbarCmd.label "Bar Offer E-bost">
+<!ENTITY showMessengerToolbarCmd.accesskey "O">
+<!ENTITY customizeToolbar.label "Cyfaddasu…">
+<!ENTITY customizeToolbar.accesskey "C">
+
+<!ENTITY messagePaneLayoutStyle.label "Cynllun">
+<!ENTITY messagePaneLayoutStyle.accesskey "C">
+<!ENTITY messagePaneClassic.label "Golwg Glasurol">
+<!ENTITY messagePaneClassic.accesskey "l">
+<!ENTITY messagePaneWide.label "Golwg Lydan">
+<!ENTITY messagePaneWide.accesskey "L">
+<!ENTITY messagePaneVertical.label "Golwr Fertigol">
+<!ENTITY messagePaneVertical.accesskey "F">
+<!ENTITY showFolderPaneCmd.label "Paen Ffolder">
+<!ENTITY showFolderPaneCmd.accesskey "F">
+<!ENTITY showFolderPaneColsCmd.label "Colofnau Paenau Ffolderi">
+<!ENTITY showFolderPaneColsCmd.accesskey "P">
+<!ENTITY showMessageCmd.label "Paen Neges">
+<!ENTITY showMessageCmd.accesskey "N">
+
+<!ENTITY folderView.label "Ffolderi">
+<!ENTITY folderView.accesskey "F">
+<!ENTITY unifiedFolders.label "Unedig">
+<!ENTITY unifiedFolders.accesskey "U">
+<!ENTITY allFolders.label "Popeth">
+<!ENTITY allFolders.accesskey "P">
+<!ENTITY unreadFolders.label "Heb ei Ddarllen">
+<!ENTITY unreadFolders.accesskey "H">
+<!ENTITY favoriteFolders.label "Ffefryn">
+<!ENTITY favoriteFolders.accesskey "F">
+<!ENTITY recentFolders.label "Diweddar">
+<!ENTITY recentFolders.accesskey "D">
+<!ENTITY compactVersion.label "Golwg Cryno">
+<!ENTITY compactVersion.accesskey "G">
+<!ENTITY folderPaneBar.label "Bar Offer Paen Ffolder">
+<!ENTITY folderPaneBar.accesskey "B">
+
+<!-- Sort Menu -->
+<!ENTITY sortMenu.label "Trefnu yn ôl">
+<!ENTITY sortMenu.accesskey "T">
+<!ENTITY sortByDateCmd.label "Dyddiad">
+<!ENTITY sortByDateCmd.accesskey "D">
+<!ENTITY sortByReceivedCmd.label "Derbyn">
+<!ENTITY sortByReceivedCmd.accesskey "e">
+<!ENTITY sortByStarCmd.label "Seren">
+<!ENTITY sortByStarCmd.accesskey "S">
+<!ENTITY sortByAttachmentsCmd.label "Atodiadau">
+<!ENTITY sortByAttachmentsCmd.accesskey "A">
+<!ENTITY sortByPriorityCmd.label "Blaenoriaeth">
+<!ENTITY sortByPriorityCmd.accesskey "B">
+<!ENTITY sortBySizeCmd.label "Maint">
+<!ENTITY sortBySizeCmd.accesskey "M">
+<!ENTITY sortByStatusCmd.label "Statws">
+<!ENTITY sortByStatusCmd.accesskey "S">
+<!ENTITY sortByTagsCmd.label "Tagiau">
+<!ENTITY sortByTagsCmd.accesskey "g">
+<!ENTITY sortByJunkStatusCmd.label "Statws Sbam">
+<!ENTITY sortByJunkStatusCmd.accesskey "S">
+<!ENTITY sortBySubjectCmd.label "Pwnc">
+<!ENTITY sortBySubjectCmd.accesskey "P">
+<!ENTITY sortByFromCmd.label "Oddi wrth">
+<!ENTITY sortByFromCmd.accesskey "O">
+<!ENTITY sortByRecipientCmd.label "Derbynnydd">
+<!ENTITY sortByRecipientCmd.accesskey "D">
+<!ENTITY sortByCorrespondentCmd.label "Cyfathrebwyr">
+<!ENTITY sortByCorrespondentCmd.accesskey "f">
+<!ENTITY sortByUnreadCmd.label "Darllenwyd">
+<!ENTITY sortByUnreadCmd.accesskey "D">
+<!ENTITY sortByOrderReceivedCmd.label "Trefn Derbyn">
+<!ENTITY sortByOrderReceivedCmd.accesskey "T">
+<!ENTITY sortAscending.label "Esgyn">
+<!ENTITY sortAscending.accesskey "E">
+<!ENTITY sortDescending.label "Disgyn">
+<!ENTITY sortDescending.accesskey "D">
+<!ENTITY sortThreaded.label "Edafwyd">
+<!ENTITY sortThreaded.accesskey "d">
+<!ENTITY sortUnthreaded.label "Dim edefyn">
+<!ENTITY sortUnthreaded.accesskey "i">
+<!ENTITY groupBySort.label "Grwpio yn ôl Trefnu">
+<!ENTITY groupBySort.accesskey "G">
+<!ENTITY msgsMenu.label "Negeseuon">
+<!ENTITY msgsMenu.accesskey "N">
+<!ENTITY threads.label "Edafedd">
+<!ENTITY threads.accesskey "d">
+<!ENTITY allMsgsCmd.label "Popeth">
+<!ENTITY allMsgsCmd.accesskey "P">
+<!ENTITY expandAllThreadsCmd.label "Ehangu Pob Edefyn">
+<!ENTITY expandAllThreadsCmd.accesskey "E">
+<!ENTITY expandAllThreadsCmd.key "*">
+<!ENTITY collapseAllThreadsCmd.label "Cau Pob Edefyn">
+<!ENTITY collapseAllThreadsCmd.accesskey "C">
+<!ENTITY collapseAllThreadsCmd.key "\">
+<!ENTITY unreadMsgsCmd.label "Heb ei Ddarllen">
+<!ENTITY unreadMsgsCmd.accesskey "H">
+<!ENTITY threadsWithUnreadCmd.label "Edafedd gyda rhai Heb eu Darllen">
+<!ENTITY threadsWithUnreadCmd.accesskey "H">
+<!ENTITY watchedThreadsWithUnreadCmd.label "Gwylio Edafedd gyda rhai Heb eu Darllen">
+<!ENTITY watchedThreadsWithUnreadCmd.accesskey "G">
+<!ENTITY ignoredThreadsCmd.label "Edafedd Anwybyddwyd">
+<!ENTITY ignoredThreadsCmd.accesskey "n">
+
+<!ENTITY headersMenu.label "Penynnau">
+<!ENTITY headersMenu.accesskey "P">
+<!ENTITY headersAllCmd.label "Popeth">
+<!ENTITY headersAllCmd.accesskey "P">
+<!ENTITY headersNormalCmd.label "Arferol">
+<!ENTITY headersNormalCmd.accesskey "A">
+<!ENTITY bodyMenu.label "Corff y Neges Fel">
+<!ENTITY bodyMenu.accesskey "o">
+<!ENTITY bodyAllowHTML.label "HTML Gwreiddiol">
+<!ENTITY bodyAllowHTML.accesskey "H">
+<!ENTITY bodySanitized.label "HTML Syml">
+<!ENTITY bodySanitized.accesskey "S">
+<!ENTITY bodyAsPlaintext.label "Testun Plaen">
+<!ENTITY bodyAsPlaintext.accesskey "P">
+<!ENTITY bodyAllParts.label "Pob Rhan o'r Corff">
+<!ENTITY bodyAllParts.accesskey "P">
+
+<!ENTITY bodyMenuFeed.label "Corff Neges Llif Fel">
+<!ENTITY bodyMenuFeed.accesskey "L">
+<!ENTITY viewFeedWebPage.label "Tudalen Gwe">
+<!ENTITY viewFeedWebPage.accesskey "G">
+<!ENTITY viewFeedSummary.label "Crynodeb">
+<!ENTITY viewFeedSummary.accesskey "r">
+<!ENTITY viewFeedSummaryFeedPropsPref.label "Fformat Rhagosodedig">
+<!ENTITY viewFeedSummaryFeedPropsPref.accesskey "R">
+
+<!ENTITY viewAttachmentsInlineCmd.label "Dangos Atodiadau Mewnlin">
+<!ENTITY viewAttachmentsInlineCmd.accesskey "D">
+
+<!ENTITY pageSourceCmd.label "Ffynhonnell y Neges">
+<!ENTITY pageSourceCmd.accesskey "F">
+<!ENTITY pageSourceCmd.key "u">
+<!ENTITY getNewMessagesCmd.key "y">
+<!ENTITY getAllNewMessagesCmd.key "Y">
+
+<!-- Search Menu -->
+<!ENTITY findMenu.label "Canfod">
+<!ENTITY findMenu.accesskey "f">
+<!ENTITY findCmd.label "Canfod yn y Neges…">
+<!ENTITY findCmd.accesskey "a">
+<!ENTITY findCmd.key "f">
+<!ENTITY findAgainCmd.label "Canfod Eto">
+<!ENTITY findAgainCmd.accesskey "E">
+<!ENTITY findAgainCmd.key "g">
+<!ENTITY findAgainCmd.key2 "VK_F3">
+<!ENTITY findPrevCmd.key "g">
+<!ENTITY findPrevCmd.key2 "VK_F3">
+<!ENTITY searchMailCmd.label "Chwilio Negeseuon…">
+<!ENTITY searchMailCmd.accesskey "N">
+<!ENTITY searchMailCmd.key "f">
+<!ENTITY glodaSearchCmd.label "Chwilio Eang…">
+<!ENTITY glodaSearchCmd.accesskey "C">
+<!ENTITY searchAddressesCmd.label "Chwilio Cyfeiriadau…">
+<!ENTITY searchAddressesCmd.accesskey "y">
+
+<!-- Go Menu -->
+<!ENTITY goMenu.label "Mynd">
+<!ENTITY goMenu.accesskey "M">
+<!ENTITY nextMenu.label "Nesaf">
+<!ENTITY nextMenu.accesskey "N">
+<!ENTITY nextMsgCmd.label "Neges">
+<!ENTITY nextMsgCmd.accesskey "N">
+<!ENTITY nextMsgCmd.key "f">
+<!ENTITY nextUnreadMsgCmd.label "Neges Heb ei Darllen">
+<!ENTITY nextUnreadMsgCmd.accesskey "H">
+<!ENTITY nextUnreadMsgCmd.key "n">
+<!ENTITY nextStarredMsgCmd.label "Neges Serenog">
+<!ENTITY nextStarredMsgCmd.accesskey "S">
+<!ENTITY nextUnreadThread.label "Edafedd Heb eu Darllen">
+<!ENTITY nextUnreadThread.accesskey "D">
+<!ENTITY nextUnreadThread.key "t">
+<!ENTITY prevMenu.label "Blaenorol">
+<!ENTITY prevMenu.accesskey "B">
+<!ENTITY prevMsgCmd.label "Neges">
+<!ENTITY prevMsgCmd.accesskey "N">
+<!ENTITY prevMsgCmd.key "b">
+<!ENTITY prevUnreadMsgCmd.label "Neges Heb ei Darllen">
+<!ENTITY prevUnreadMsgCmd.accesskey "D">
+<!ENTITY prevUnreadMsgCmd.key "p">
+<!ENTITY goForwardCmd.label "Ymlaen">
+<!ENTITY goForwardCmd.accesskey "Y">
+<!ENTITY goForwardCmd.commandKey "]">
+<!ENTITY goBackCmd.label "Nôl">
+<!ENTITY goBackCmd.accesskey "N">
+<!ENTITY goBackCmd.commandKey "[">
+<!ENTITY goChatCmd.label "Sgwrsio">
+<!ENTITY goChatCmd.accesskey "g">
+<!ENTITY goChatCmd2.key "g">
+<!ENTITY prevStarredMsgCmd.label "Neges Serennog">
+<!ENTITY prevStarredMsgCmd.accesskey "S">
+<!ENTITY folderMenu.label "Ffolder">
+<!ENTITY folderMenu.accesskey "o">
+<!ENTITY goRecentlyClosedTabs.label "Tabiau Wedi'u Cau'n Ddiweddar">
+<!ENTITY goRecentlyClosedTabs.accesskey "T">
+<!ENTITY startPageCmd.label "Tudalen Cychwyn E-bost">
+<!ENTITY startPageCmd.accesskey "T">
+
+<!-- Message Menu -->
+<!ENTITY msgMenu.label "Neges">
+<!ENTITY msgMenu.accesskey "N">
+<!ENTITY newMsgCmd.label "Neges Newydd">
+<!ENTITY newMsgCmd.accesskey "N">
+<!ENTITY newNewMsgCmd.label "Neges">
+<!ENTITY newNewMsgCmd.accesskey "e">
+<!ENTITY archiveMsgCmd.label "Archif">
+<!ENTITY archiveMsgCmd.accesskey "A">
+<!ENTITY archiveMsgCmd.key "a">
+<!ENTITY cancelNewsMsgCmd.label "Diddymu Neges">
+<!ENTITY cancelNewsMsgCmd.accesskey "D">
+<!ENTITY replyMsgCmd.label "Ateb">
+<!ENTITY replyMsgCmd.accesskey "A">
+<!ENTITY replyMsgCmd.key "r">
+<!ENTITY replySenderCmd.label "Ateb i'r Anfonwr yn Unig">
+<!ENTITY replySenderCmd.accesskey "t">
+<!ENTITY replyNewsgroupCmd2.label "Dilyn Grŵp Newyddion">
+<!ENTITY replyNewsgroupCmd2.accesskey "D">
+<!ENTITY replyToAllMsgCmd.label "Ateb i Bawb">
+<!ENTITY replyToAllMsgCmd.accesskey "B">
+<!ENTITY replyToAllMsgCmd.key "r">
+<!ENTITY replyToListMsgCmd.label "Ateb i'r Rhestr">
+<!ENTITY replyToListMsgCmd.accesskey "R">
+<!ENTITY replyToListMsgCmd.key "l">
+<!ENTITY forwardMsgCmd.label "Ymlaen">
+<!ENTITY forwardMsgCmd.accesskey "Y">
+<!ENTITY forwardMsgCmd.key "l">
+<!ENTITY forwardAsMenu.label "Ymlaen Fel">
+<!ENTITY forwardAsMenu.accesskey "Y">
+<!ENTITY forwardAsInline.label "Mewnlin">
+<!ENTITY forwardAsInline.accesskey "M">
+<!ENTITY forwardAsAttachmentCmd.label "Atodiad">
+<!ENTITY forwardAsAttachmentCmd.accesskey "A">
+<!ENTITY editAsNewMsgCmd.label "Golygu fel Neges Newydd">
+<!ENTITY editAsNewMsgCmd.accesskey "G">
+<!ENTITY editAsNewMsgCmd.key "g">
+<!ENTITY editDraftMsgCmd.label "Golygu Neges Ddrafft">
+<!ENTITY editDraftMsgCmd.accesskey "D">
+<!ENTITY editTemplateMsgCmd.label "Golygu Templed">
+<!ENTITY editTemplateMsgCmd.accesskey "T">
+<!ENTITY newMsgFromTemplateCmd.label "Neges Newydd o Dempled">
+<!ENTITY newMsgFromTemplateCmd.keycode "VK_RETURN"><!-- do not change "VK_RETURN" -->
+<!ENTITY createFilter.label "Creu Hidl o'r Neges…">
+<!ENTITY createFilter.accesskey "H">
+<!ENTITY moveMsgToMenu.label "Symud i">
+<!ENTITY moveMsgToMenu.accesskey "S">
+<!ENTITY moveCopyMsgRecentMenu.label "Diweddar">
+<!ENTITY moveCopyMsgRecentMenu.accesskey "D">
+<!ENTITY copyMessageLocation.label "Copïo Lleoliad Neges">
+<!ENTITY copyMessageLocation.accesskey "L">
+<!ENTITY copyMsgToMenu.label "Copïo i">
+<!ENTITY copyMsgToMenu.accesskey "C">
+<!ENTITY moveToFolderAgain.label "Symud Eto">
+<!ENTITY moveToFolderAgain.accesskey "y">
+<!ENTITY moveToFolderAgainCmd.key "m">
+<!ENTITY killThreadMenu.label "Anwybyddu'r Edefyn">
+<!ENTITY killThreadMenu.accesskey "A">
+<!ENTITY killThreadMenu.key "k">
+<!ENTITY killSubthreadMenu.label "Anwybyddu'r Is-Edefyn">
+<!ENTITY killSubthreadMenu.accesskey "I">
+<!ENTITY killSubthreadMenu.key "k">
+<!ENTITY watchThreadMenu.label "Gwylio'r Edefyn">
+<!ENTITY watchThreadMenu.accesskey "w">
+<!ENTITY watchThreadMenu.key "w">
+<!ENTITY tagMenu.label "Tag">
+<!ENTITY tagMenu.accesskey "g">
+<!ENTITY tagCmd0.key "0">
+<!ENTITY tagCmd1.key "1">
+<!ENTITY tagCmd2.key "2">
+<!ENTITY tagCmd3.key "3">
+<!ENTITY tagCmd4.key "4">
+<!ENTITY tagCmd5.key "5">
+<!ENTITY tagCmd6.key "6">
+<!ENTITY tagCmd7.key "7">
+<!ENTITY tagCmd8.key "8">
+<!ENTITY tagCmd9.key "9">
+<!ENTITY markMenu.label "Marcio">
+<!ENTITY markMenu.accesskey "M">
+<!ENTITY toggleReadCmd.key "m">
+<!ENTITY markAsReadCmd.label "Wedi ei Ddarllen">
+<!ENTITY markAsReadCmd.accesskey "W">
+<!ENTITY markAsUnreadCmd.label "Heb ei Ddarllen">
+<!ENTITY markAsUnreadCmd.accesskey "H">
+<!ENTITY markThreadAsReadCmd.label "Edefyn wedi'i Ddarllen">
+<!ENTITY markThreadAsReadCmd.accesskey "D">
+<!ENTITY markThreadAsReadCmd.key "r">
+<!ENTITY markReadByDateCmd.label "Wedi Darllen yn ôl Dyddiad…">
+<!ENTITY markReadByDateCmd.accesskey "D">
+<!ENTITY markReadByDateCmd.key "c">
+<!ENTITY markAllReadCmd.label "Popeth Wedi ei Ddarllen">
+<!ENTITY markAllReadCmd.accesskey "P">
+<!ENTITY markAllReadCmd.key "c">
+<!ENTITY markStarredCmd.label "Ychwanegu Seren">
+<!ENTITY markStarredCmd.accesskey "S">
+<!ENTITY markStarredCmd.key "S">
+<!ENTITY markAsJunkCmd.label "Fel Sbam">
+<!ENTITY markAsJunkCmd.accesskey "b">
+<!ENTITY markAsJunkCmd.key "j">
+<!ENTITY markAsNotJunkCmd.label "Fel Nid Sbam">
+<!ENTITY markAsNotJunkCmd.accesskey "N">
+<!ENTITY markAsNotJunkCmd.key "j">
+<!ENTITY recalculateJunkScoreCmd.label "Rhedeg Rheolydd E-bost Sbam">
+<!ENTITY recalculateJunkScoreCmd.accesskey "R">
+<!ENTITY openMessageWindowCmd.label "Agor Neges">
+<!ENTITY openMessageWindowCmd.accesskey "A">
+<!ENTITY openMessageWindowCmd.key "o">
+<!ENTITY openInConversationCmd.label "Agor mewn Sgwrs">
+<!ENTITY openInConversationCmd.accesskey "s">
+<!ENTITY openInConversationCmd.key "o">
+<!ENTITY openAttachmentListCmd.label "Atodiadau">
+<!ENTITY openAttachmentListCmd.accesskey "t">
+<!ENTITY openFeedMessage1.label "Wrth Agor Negeseuon Llif">
+<!ENTITY openFeedMessage1.accesskey "L">
+<!ENTITY openFeedWebPage.label "Agor fel Tudalen Gwe">
+<!ENTITY openFeedWebPage.accesskey "G">
+<!ENTITY openFeedSummary.label "Agor fel Crynodeb">
+<!ENTITY openFeedSummary.accesskey "C">
+<!ENTITY openFeedWebPageInMP.label "Toglo Tudalen We a Chrynodeb mewn Paen Neges">
+<!ENTITY openFeedWebPageInMP.accesskey "T">
+
+<!-- Windows Menu -->
+<!ENTITY windowMenu.label "Ffenestr">
+
+<!-- Tools Menu -->
+<!ENTITY tasksMenu.label "Offer">
+<!ENTITY tasksMenu.accesskey "O">
+<!ENTITY messengerCmd.label "E-bost a Grwpiau Newyddion">
+<!ENTITY messengerCmd.accesskey "E">
+<!ENTITY addressBookCmd.label "Llyfr Cyfeiriadau">
+<!ENTITY addressBookCmd.accesskey "L">
+<!ENTITY addressBookCmd.key "B">
+<!ENTITY addons.label "Ychwanegion">
+<!ENTITY addons.accesskey "a">
+<!ENTITY addonPrefs.label "Dewisiadau Ychwanegion">
+<!ENTITY addonPrefs.accesskey "Y">
+<!ENTITY addonPrefsUnix.label "Dewisiadau Ychwanegion">
+<!ENTITY addonPrefsUnix.accesskey "D">
+<!ENTITY addonNoPrefs.label "Heb ganfod gosodiadau Ychwanegion.">
+<!ENTITY activitymanager.label "Rheolwr Gweithgaredd">
+<!ENTITY activitymanager.accesskey "R">
+<!ENTITY imAccountsStatus.label "Statws Sgwrsio">
+<!ENTITY imAccountsStatus.accesskey "t">
+<!ENTITY imStatus.available          "Ar Gael">
+<!ENTITY imStatus.unavailable        "Ddim ar Gael">
+<!ENTITY imStatus.offline            "All-lein">
+<!ENTITY imStatus.showAccounts       "Dangos Cyfrifon…">
+<!ENTITY joinChatCmd.label "Ymuno â Sgwrs…">
+<!ENTITY joinChatCmd.accesskey "Y">
+<!ENTITY savedFiles.label "Ffeiliau wedi'u Cadw">
+<!ENTITY savedFiles.accesskey "F">
+<!ENTITY savedFiles.key "j">
+<!ENTITY filtersCmd2.label "Hidlau Negeseuon">
+<!ENTITY filtersCmd2.accesskey "H">
+<!ENTITY filtersApply.label "Rhedeg Hidlau ar Ffolder">
+<!ENTITY filtersApply.accesskey "R">
+<!ENTITY filtersApplyToSelection.label "Rhedeg Hidlau ar Negeseuon Penodol">
+<!ENTITY filtersApplyToSelection.accesskey "P">
+<!ENTITY filtersApplyToMessage.label "Rhedeg Hidlau ar Neges">
+<!ENTITY filtersApplyToMessage.accesskey "N">
+<!ENTITY runJunkControls.label "Rhedeg Rheolydd Sbam ar Ffolder">
+<!ENTITY runJunkControls.accesskey "R">
+<!ENTITY deleteJunk.label "Dileu E-bost wedi'i Nodi fel Sbam yn y Ffolder">
+<!ENTITY deleteJunk.accesskey "D">
+<!ENTITY importCmd.label "Mewnforio…">
+<!ENTITY importCmd.accesskey "M">
+<!ENTITY clearRecentHistory.label "Clirio Hanes Diweddar…">
+<!ENTITY clearRecentHistory.accesskey "H">
+<!ENTITY accountManagerCmd2.label "Gosodiadau'r Cyfrif">
+<!ENTITY accountManagerCmd2.accesskey "G">
+<!-- LOCALIZATION NOTE (accountManagerCmdUnix.accesskey):
+     Belongs to accountManagerCmd.label, which is placed under the Edit menu
+     on Unix systems
+  -->
+<!ENTITY accountManagerCmdUnix2.accesskey "A">
+
+<!-- Developer Tools Submenu -->
+<!ENTITY devtoolsMenu.label "Offer Datblygwyr">
+<!ENTITY devtoolsMenu.accesskey "D">
+<!ENTITY devToolboxCmd.label "Blwch Offer Datblygwyr">
+<!ENTITY devToolboxCmd.accesskey "B">
+<!ENTITY devToolboxCmd.commandkey "i">
+<!ENTITY debugAddonsCmd.label "Ychwanegion Dadfygio">
+<!ENTITY debugAddonsCmd.accesskey "Y">
+<!ENTITY tabsDebugCmd.label "Dadfygiwr Cynnwys Ffrâm">
+<!ENTITY tabsDebugCmd.accesskey "F">
+<!ENTITY errorConsoleCmd.label "Consol Gwall">
+<!ENTITY errorConsoleCmd.accesskey "C">
+<!ENTITY errorConsoleCmd.commandkey "j">
+
+<!-- Mail Toolbar -->
+<!ENTITY getMsgButton1.label "Estyn Negeseuon">
+<!ENTITY newMsgButton.label "Ysgrifennu">
+<!ENTITY replyButton.label "Ateb">
+<!ENTITY replyAllButton.label "Ateb Pawb">
+<!ENTITY replyListButton.label "Ateb i'r Rhestr">
+<!ENTITY forwardButton.label "Ymlaen">
+<!ENTITY fileButton.label "Ffeil">
+<!ENTITY archiveButton.label "Archifo">
+<!ENTITY openConversationButton.label "Sgwrs">
+<!ENTITY nextButton.label "Nesaf">
+<!ENTITY nextButtonToolbarItem.label "Nesaf Heb ei Ddarllen">
+<!ENTITY nextMsgButton.label "Nesaf">
+<!ENTITY previousButton.label "Blaenorol">
+<!ENTITY previousButtonToolbarItem.label "Blaenorol Heb ei Ddarllen">
+<!ENTITY previousMsgButton.label "Blaenorol">
+<!ENTITY backButton1.label "Nôl">
+<!ENTITY goForwardButton1.label "Ymlaen">
+<!ENTITY deleteItem.title "Dileu">
+<!ENTITY deleteButton.label "Dileu">
+<!ENTITY undeleteButton.label "Dad-ddileu">
+<!ENTITY markButton.label "Marcio">
+<!ENTITY printButton.label "Argraffu">
+<!ENTITY stopButton.label "Atal">
+<!ENTITY throbberItem.title "Dangosydd Gweithgaredd">
+<!ENTITY junkItem.title "Sbam">
+<!ENTITY junkButton.label "Sbam">
+<!ENTITY notJunkButton.label "Nid Sbam">
+<!ENTITY addressBookButton.label "Llyfr Cyfeiriadau">
+<!ENTITY chatButton.label "Sgwrsio">
+<!ENTITY glodaSearch.title "Chwilio Eang">
+<!ENTITY searchItem.title "Chwilio Cyflym">
+<!ENTITY mailViewsToolbarItem.title "Golwg E-bost">
+<!ENTITY folderLocationToolbarItem.title "Lleoliad Ffolder">
+<!ENTITY tagButton.label "Tag">
+<!ENTITY compactButton.label "Cywasgu">
+<!ENTITY appmenuButton.label "AppMenu">
+
+<!-- Mail Toolbar Tooltips-->
+<!ENTITY advancedButton.tooltip "Chwilio neges uwch">
+<!ENTITY getMsgButton.tooltip "Estyn negeseuon newydd">
+<!ENTITY getAllNewMsgCmd.label "Estyn Pob Neges Newydd">
+<!ENTITY getAllNewMsgCmd.accesskey "E">
+<!ENTITY newMsgButton.tooltip "Creu neges newydd">
+<!ENTITY replyButton.tooltip "Ateb y neges">
+<!ENTITY replyAllButton.tooltip "Ateb yr anfonwr a phob derbyniwr">
+<!ENTITY replyListButton.tooltip "Ateb i'r rhestr e-bost">
+<!ENTITY forwardButton.tooltip "Anfon y neges ymlaen">
+<!ENTITY forwardAsInline.tooltip "Anfon neges dewiswyd ymlaen fel testun mewnlin">
+<!ENTITY forwardAsAttachment.tooltip "Anfon neges dewiswyd ymlaen fel atodiad">
+<!ENTITY fileButton.tooltip "Ffeilio'r neges">
+<!ENTITY archiveButton.tooltip "Archifo'r negeseuon">
+<!ENTITY openMsgConversationButton.tooltip "Dangos sgwrs neges sydd wedi ei dewis">
+<!ENTITY nextButton.tooltip "Symud i'r neges nesaf heb ei darllen">
+<!ENTITY nextMsgButton.tooltip "Symud i'r neges nesaf">
+<!ENTITY previousButton.tooltip "Symud i'r neges heb ei darllen diwethaf">
+<!ENTITY previousMsgButton.tooltip "Symud i'r neges flaenorol">
+<!ENTITY goForwardButton.tooltip "Mynd ymlaen un neges">
+<!ENTITY goBackButton.tooltip "Mynd nôl un neges">
+<!ENTITY deleteButton.tooltip "Dileu'r neges neu'r ffolder">
+<!ENTITY undeleteButton.tooltip "Dad-ddileu'r neges">
+<!ENTITY markButton.tooltip "Marcio negeseuon">
+<!ENTITY printButton.tooltip "Argraffu'r neges">
+<!ENTITY stopButton.tooltip "Atal y trosglwyddiad cyfredol">
+<!ENTITY junkButton.tooltip "Marcio'r neges fel sbam">
+<!ENTITY notJunkButton.tooltip "Marcio'r neges fel nid sbam">
+<!ENTITY addressBookButton.tooltip "Mynd i'r llyfr cyfeiriadau">
+<!ENTITY chatButton.tooltip "Dangos y tab Sgwrsio">
+<!ENTITY tagButton.tooltip "Tagio negeseuon">
+<!ENTITY compactButton.tooltip "Tynnu negeseuon wedi'u dileu o'r ffolder">
+<!ENTITY appmenuButton1.tooltip "Dangos Dewislen &brandShortName;">
+<!ENTITY addonsButton.tooltip "Rheoli eich ychwanegion">
+
+<!-- Toolbar Button Popup -->
+<!ENTITY buttonMenuForwardAsInline.label "Anfon Ymlaen fel Mewnlin">
+<!ENTITY buttonMenuForwardAsAttachment.label "Anfon Ymlaen fel Atodiad">
+
+<!-- Remote Content Button Popup -->
+<!ENTITY remoteContentOptionsAllowForMsg.label "Dangos cynnwys pell o fewn y neges hon">
+<!ENTITY remoteContentOptionsAllowForMsg.accesskey "D">
+<!ENTITY editRemoteContentSettings.label "Golygu dewisiadau cynnwys pell…">
+<!ENTITY editRemoteContentSettings.accesskey "G">
+<!ENTITY editRemoteContentSettingsUnix.label "Golygu dewisiadau cynnwys pell…">
+<!ENTITY editRemoteContentSettingsUnix.accesskey "d">
+
+<!-- Phishing Button Popup -->
+<!ENTITY phishingOptionIgnore.label "Anwybyddu rhybudd am y neges hon">
+<!ENTITY phishingOptionIgnore.accesskey "A">
+<!ENTITY phishingOptionSettings.label "Golygu dewisiadau canfod twyll…">
+<!ENTITY phishingOptionSettings.accesskey "o">
+<!ENTITY phishingOptionSettingsUnix.label "Golygu dewisiadau canfod twyll…">
+<!ENTITY phishingOptionSettingsUnix.accesskey "o">
+
+<!-- AppMenu Popup -->
+<!ENTITY appmenuNewMsgCmd.label "Neges Newydd">
+<!ENTITY appmenuNewContactCmd.label "Cysylltiad Llyfr Cyfeiriadau…">
+<!ENTITY appmenuEditMenu.label "Golygu">
+<!ENTITY appmenuToolbarLayout.label "Cynllun Bar Offer…">
+<!ENTITY appmenuSelectThread.label "Dewis Edefyn">
+<!ENTITY appmenuSelectFlagged.label "Estyn Negeseuon Serennog">
+
+<!-- Tags Menu Popup -->
+<!ENTITY addNewTag.label "Tag Newydd…">
+<!ENTITY addNewTag.accesskey "T">
+<!ENTITY manageTags.label "Rheoli Tagiau…">
+<!ENTITY manageTags.accesskey "T">
+
+<!-- Folder Pane -->
+<!ENTITY folderNameColumn.label "Enw">
+<!ENTITY folderUnreadColumn.label "Heb ei Ddarllen">
+<!ENTITY folderTotalColumn.label "Cyfanswm">
+<!ENTITY folderSizeColumn.label "Maint">
+
+<!-- Folder Pane Context Menu -->
+<!ENTITY folderContextGetMessages.label "Estyn Negeseuon">
+<!ENTITY folderContextGetMessages.accesskey "s">
+<!ENTITY folderContextMarkAllFoldersRead.label "Marcio Pob Ffolder Wedi'u Darllen">
+<!ENTITY folderContextPauseAllUpdates.label "Oedi Pob Diweddariad">
+<!ENTITY folderContextPauseUpdates.label "Oedi Diweddariadau">
+<!ENTITY folderContextPauseUpdates.accesskey "D">
+<!ENTITY folderContextOpenInNewWindow.label "Agor mewn Ffenestr Newydd">
+<!ENTITY folderContextOpenInNewWindow.accesskey "N">
+<!ENTITY folderContextOpenNewTab.label "Agor mewn Tab Newydd">
+<!ENTITY folderContextOpenNewTab.accesskey "T">
+<!ENTITY folderContextNew.label "Is ffolder Newydd…">
+<!ENTITY folderContextNew.accesskey "I">
+<!ENTITY folderContextRename.label "Ailenwi">
+<!ENTITY folderContextRename.accesskey "A">
+<!ENTITY folderContextRemove.label "Dileu">
+<!ENTITY folderContextRemove.accesskey "D">
+<!ENTITY folderContextCompact.label "Cywasgu">
+<!ENTITY folderContextCompact.accesskey "C">
+<!ENTITY folderContextEmptyTrash.label "Gwagio'r Sbwriel">
+<!ENTITY folderContextEmptyTrash.accesskey "G">
+<!ENTITY folderContextEmptyJunk.label "Gwagio'r Sbam">
+<!ENTITY folderContextEmptyJunk.accesskey "S">
+<!ENTITY folderContextSendUnsentMessages.label "Anfon Negeseuon heb eu Hanfon">
+<!ENTITY folderContextSendUnsentMessages.accesskey "A">
+<!ENTITY folderContextUnsubscribe.label "Dad-danysgrifio">
+<!ENTITY folderContextUnsubscribe.accesskey "D">
+<!ENTITY folderContextMarkNewsgroupRead.label "Marcio Grŵp Newyddion Wedi'i Ddarllen">
+<!ENTITY folderContextMarkNewsgroupRead.accesskey "G">
+<!ENTITY folderContextMarkMailFolderRead.label "Marcio Ffolder Wedi'i Ddarllen">
+<!ENTITY folderContextMarkMailFolderRead.accesskey "W">
+<!ENTITY folderContextSubscribe.label "Tanysgrifio…">
+<!ENTITY folderContextSubscribe.accesskey "T">
+<!ENTITY folderContextSearchForMessages.label "Chwilio Negeseuon…">
+<!ENTITY folderContextSearchForMessages.accesskey "C">
+<!ENTITY folderContextProperties2.label "Priodweddau">
+<!ENTITY folderContextProperties2.accesskey "P">
+<!ENTITY folderContextFavoriteFolder.label "Hoff Ffolder">
+<!ENTITY folderContextFavoriteFolder.accesskey "H">
+<!ENTITY folderContextSettings2.label "Gosodiadau">
+<!ENTITY folderContextSettings2.accesskey "o">
+
+<!-- Search Bar -->
+<!ENTITY SearchNameOrEmail.label "Mae'r Enw neu E-bost yn cynnwys:">
+<!ENTITY SearchNameOrEmail.accesskey "E">
+
+<!-- Gloda Search Bar -->
+<!ENTITY glodaSearchBar.placeholder "Chwilio negeseuon…">
+
+<!-- Quick Search Menu Bar -->
+<!ENTITY searchSubjectMenu.label "Pwnc">
+<!ENTITY searchFromMenu.label "Oddi wrth">
+<!ENTITY searchSubjectOrFromMenu.label "Pwnc neu Oddi wrth">
+<!ENTITY searchRecipient.label "At neu Cc">
+<!ENTITY searchSubjectOrRecipientMenu.label "Pwnc, At neu Cc">
+<!ENTITY searchMessageBody.label "Neges Gyfan">
+<!ENTITY saveAsVirtualFolderMenu.label "Cadw'r Chwilio fel Ffolder…">
+
+<!-- Thread Pane -->
+<!ENTITY selectColumn.label "Dewis Negeseuon">
+<!ENTITY threadColumn.label "Edefyn">
+<!ENTITY fromColumn.label "Oddi wrth">
+<!ENTITY recipientColumn.label "Derbynnydd">
+<!ENTITY correspondentColumn.label "Cyfathrebwyr">
+<!ENTITY subjectColumn.label "Pwnc">
+<!ENTITY dateColumn.label "Dyddiad">
+<!ENTITY priorityColumn.label "Blaenoriaeth">
+<!ENTITY tagsColumn.label "Tag">
+<!ENTITY accountColumn.label "Cyfrif">
+<!ENTITY statusColumn.label "Statws">
+<!ENTITY sizeColumn.label "Maint">
+<!ENTITY junkStatusColumn.label "Statws Sbam">
+<!ENTITY unreadColumn.label "Heb ei Ddarllen">
+<!ENTITY totalColumn.label "Cyfanswm">
+<!ENTITY readColumn.label "Darllenwyd">
+<!ENTITY receivedColumn.label "Derbyniwyd">
+<!ENTITY starredColumn.label "Serennog">
+<!ENTITY locationColumn.label "Lleoliad">
+<!ENTITY idColumn.label "Trefn Derbyn">
+<!ENTITY attachmentColumn.label "Atodiadau">
+
+<!ENTITY deleteColumn.label "Dileu">
+
+<!-- Thread Pane Tooltips -->
+<!ENTITY columnChooser2.tooltip "Dewis colofnau i'w dangos">
+<!ENTITY selectColumn.tooltip "Toglo dewis pob neges">
+<!ENTITY threadColumn2.tooltip "Dangos edafedd negeseuon">
+<!ENTITY fromColumn2.tooltip "Trefnu yn ôl anfonwr">
+<!ENTITY recipientColumn2.tooltip "Trefnu yn ôl derbyniwr">
+<!ENTITY correspondentColumn2.tooltip "Trefnu yn ôl cyfathrebwyr">
+<!ENTITY subjectColumn2.tooltip "Trefnu yn ôl pwnc">
+<!ENTITY dateColumn2.tooltip "Trefnu yn ôl dyddiad">
+<!ENTITY priorityColumn2.tooltip "Trefnu yn ôl blaenoriaeth">
+<!ENTITY tagsColumn2.tooltip "Trefnu yn ôl tagiau">
+<!ENTITY accountColumn2.tooltip "Trefnu yn ôl cyfrif">
+<!ENTITY statusColumn2.tooltip "Trefnu yn ôl statws">
+<!ENTITY sizeColumn2.tooltip "Trefnu yn ôl maint">
+<!ENTITY junkStatusColumn2.tooltip "Trefnu yn ôl statws sbam">
+<!ENTITY unreadColumn2.tooltip "Nifer y negeseuon heb eu darllen yn yr edafedd">
+<!ENTITY totalColumn2.tooltip "Cyfanswm y nifer o negeseuon yn yr edafedd">
+<!ENTITY readColumn2.tooltip "Trefnu yn ôl darllenwyd">
+<!ENTITY receivedColumn2.tooltip "Trefnu yn ôl dyddiad derbyniwyd">
+<!ENTITY starredColumn2.tooltip "Trefnu yn ôl sêr">
+<!ENTITY locationColumn2.tooltip "Trefnu yn ôl lleoliad">
+<!ENTITY idColumn2.tooltip "Trefnu yn ôl y drefn derbyniwyd">
+<!ENTITY attachmentColumn2.tooltip "Trefnu yn ôl atodiad">
+
+<!ENTITY deleteColumn.tooltip "Dileu neges">
+
+<!-- Thread Pane Context Menu -->
+<!ENTITY contextNewMsgFromTemplate.label "Neges Newydd o Dempled">
+<!ENTITY contextOpenNewWindow.label "Agor Neges mewn Ffenestr Newydd">
+<!ENTITY contextOpenNewWindow.accesskey "F">
+<!-- The contextOpenNewTab.accesskey ("T") potentially conflicts with
+     cutCmd.accessKey which is defined in textcontext.dtd from toolkit. Right
+     now, both menu items can't be visible at the same time, but should someone
+     enable copy/paste of message, this key would probably need to be changed. -->
+<!ENTITY contextOpenNewTab.label "Agor Neges mewn Tab Newydd">
+<!ENTITY contextOpenNewTab.accesskey "T">
+<!ENTITY contextOpenConversation.label "Agor Neges mewn Sgwrs">
+<!ENTITY contextOpenConversation.accesskey "s">
+<!ENTITY contextOpenContainingFolder.label "Agor Neges yn y Ffolder Cynnwys">
+<!ENTITY contextOpenContainingFolder.accesskey "A">
+<!ENTITY contextEditMsgAsNew.label "Golygu fel Neges Newydd">
+<!ENTITY contextEditMsgAsNew.accesskey "N">
+<!ENTITY contextEditDraftMsg.label "Golygu Neges Ddrafft">
+<!ENTITY contextEditTemplate.label "Golygu Templed">
+<!ENTITY contextEditTemplate.accesskey "T">
+<!ENTITY contextArchive.label "Archifo">
+<!ENTITY contextArchive.accesskey "A">
+<!ENTITY contextReplySender.label "Ateb i'r Anfonwr yn Unig">
+<!ENTITY contextReplySender.accesskey "n">
+<!ENTITY contextReplyNewsgroup2.label "Dilyn Grŵp Newyddion">
+<!ENTITY contextReplyNewsgroup2.accesskey "D">
+<!ENTITY contextReplyAll.label "Ateb i Bawb">
+<!ENTITY contextReplyAll.accesskey "B">
+<!ENTITY contextReplyList.label "Ateb i'r Rhestr">
+<!ENTITY contextReplyList.accesskey "R">
+<!ENTITY contextForward.label "Ymlaen">
+<!ENTITY contextForward.accesskey "Y">
+<!ENTITY contextForwardAsMenu.label "Ymlaen Fel">
+<!ENTITY contextForwardAsMenu.accesskey "Y">
+<!ENTITY contextForwardAsInline.label "Mewnlin">
+<!ENTITY contextForwardAsInline.accesskey "M">
+<!ENTITY contextForwardAsAttachmentItem.label "Atodiad">
+<!ENTITY contextForwardAsAttachmentItem.accesskey "A">
+<!ENTITY contextMultiForwardAsAttachment.label "Ymlaen fel Atodiadau">
+<!ENTITY contextMultiForwardAsAttachment.accesskey "A">
+<!ENTITY contextMoveMsgMenu.label "Symud i">
+<!ENTITY contextMoveMsgMenu.accesskey "S">
+<!ENTITY contextMoveCopyMsgRecentMenu.label "Diweddar">
+<!ENTITY contextMoveCopyMsgRecentMenu.accesskey "D">
+<!ENTITY contextMoveCopyMsgFavoritesMenu.label "Ffefrynnau">
+<!ENTITY contextMoveCopyMsgFavoritesMenu.accesskey "F">
+<!ENTITY contextCopyMsgMenu.label "Copïo i">
+<!ENTITY contextCopyMsgMenu.accesskey "C">
+<!ENTITY contextKillThreadMenu.label "Anwybyddu'r Edefyn">
+<!ENTITY contextKillSubthreadMenu.accesskey "I">
+<!ENTITY contextKillThreadMenu.accesskey "A">
+<!ENTITY contextKillSubthreadMenu.label "Anwybyddu'r Is-Edefyn">
+<!ENTITY contextWatchThreadMenu.label "Gwylio'r Edefyn">
+<!-- LOCALIZATION NOTE (contextWatchThreadMenu.accesskey):
+     In the en-US locale we ran out of access keys, so there is an empty access key for
+     Watch Thread. Localizers can pick a suitable key
+  -->
+<!ENTITY contextWatchThreadMenu.accesskey "">
+<!ENTITY contextSaveAs.label "Cadw Fel…">
+<!ENTITY contextSaveAs.accesskey "a">
+<!ENTITY contextPrint.label "Argraffu…">
+<!ENTITY contextPrint.accesskey "A">
+<!ENTITY contextPrintPreview.label "Rhagolwg Argraffu">
+<!ENTITY contextPrintPreview.accesskey "R">
+
+<!-- LOCALIZATION NOTE (columnPicker.applyTo.label):
+     This option in the thread pane column picker pops up a sub-menu containing
+     the "columnPicker.applyToFolder.label" and
+     "columnPicker.applyToFolderAndChildren.label" options. This item indicates
+     a desire to apply the currently displayed set of columns to some other
+     folder(s). The sub-menu items indicate whether we want to apply it to just
+     a folder or also its children.
+  -->
+<!ENTITY columnPicker.applyTo.label "Gosod y colofnau yn y…">
+<!-- LOCALIZATION NOTE (columnPicker.applyToFolder.label):
+     This option in the thread pane column picker is found on a sub-menu beneath
+     the "columnPicker.applyTo.label" alongside
+     "columnPicker.applyToFolderAndChildren.label". It indicates a desire to
+     apply the currently display thread pane column settings to a single folder
+     that the user selects using the same widget as the move to/copy to
+     mechanism (via a series of popups).
+  -->
+<!ENTITY columnPicker.applyToFolder.label "Ffolder…">
+<!-- LOCALIZATION NOTE (columnPicker.applyToFolderAndChildren.label):
+     This option in the thread pane column picker is found on a sub-menu beneath
+     the "columnPicker.applyTo.label" alongside
+     "columnPicker.applyToFolder.label". It indicates a desire to
+     apply the currently display thread pane column settings to a folder and all
+     of its descendents. The user selects the folder using the same widget as the
+     move to/copy to mechanism (via a series of popups).
+  -->
+<!ENTITY columnPicker.applyToFolderAndChildren.label "Ffolder a'i blant…">
+<!-- LOCALIZATION NOTE (columnPicker.thisFolder.label):
+     This is used in the folder selection widget for the
+     "columnPicker.applyToFolder.label" and
+     "columnPicker.applyToFolderAndChildren.label" menu options. Whenever
+     a folder has children, it results in a menu popup; the first menu item
+     in that popup is given this label to indicate that that folder should be
+     selected. For example, if folder "A" has two children, "B" and "C", then
+     when the user hovers over "A", a new popup menu will be displayed whose
+     items are "This folder", "B", and "C". This is the equivalent of the
+     "File here" option for the move to/copy to widget.
+  -->
+<!ENTITY columnPicker.thisFolder.label "Y ffolder hwn">
+
+<!-- Media (video/audio) controls -->
+<!ENTITY contextPlay.label "Chwarae">
+<!ENTITY contextPlay.accesskey "h">
+<!ENTITY contextPause.label "Oedi">
+<!ENTITY contextPause.accesskey "O">
+<!ENTITY contextMute.label "Tewi">
+<!ENTITY contextMute.accesskey "T">
+<!ENTITY contextUnmute.label "Dad-dewi">
+<!ENTITY contextUnmute.accesskey "D">
+
+<!-- Quick Search Bar -->
+<!-- LOCALIZATION NOTE (quickSearchCmd.key):
+     This is actually the key used for the global message search box; we have
+     not changed
+  -->
+<!ENTITY quickSearchCmd.key "k">
+<!-- LOCALIZATION NOTE (search.label.base1):
+     This is the base of the empty text for the global search box. We replace
+     #1 with the contents of the appropriate search.keyLabel.* value for the
+     platform.
+     The goal is to convey to the user that typing in the box will allow them
+     to search for messages globally and that there is a hotkey they can press
+     to get to the box faster. If the global indexer is disabled, the search
+     box will be collapsed and the user will never see this message.
+  -->
+<!ENTITY search.label.base1 "Chwilio #1">
+<!-- LOCALIZATION NOTE (search.keyLabel.nonmac):
+     The description of the key-binding to get into the global search box on
+     windows and linux (which use the control key). We use the key defined in
+     the quickSearchCmd.key entity defined above, the letter should match it.
+  -->
+<!ENTITY search.keyLabel.nonmac "&lt;Ctrl+K&gt;">
+<!-- LOCALIZATION NOTE (search.keyLabel.mac):
+     The description of the key-binding to get into the global search box on mac
+     systems. We use the key defined in the quickSearchCmd.key entity defined
+     above, the letter should match it.
+  -->
+<!ENTITY search.keyLabel.mac "&lt;&#x2318;K&gt;">
+
+<!-- Message Header Context Menu -->
+<!ENTITY AddToAddressBook.label "Ychwanegu i'r Llyfr Cyfeiriadau…">
+<!ENTITY AddToAddressBook.accesskey "L">
+<!ENTITY AddDirectlyToAddressBook.label "Ychwanegu i'r Llyfr Cyfeiriadau">
+<!ENTITY AddDirectlyToAddressBook.accesskey "C">
+<!ENTITY EditContact1.label "Golygu Cysylltiad">
+<!ENTITY EditContact1.accesskey "G">
+<!ENTITY ViewContact.label "Gweld Cysylltiad">
+<!ENTITY ViewContact.accesskey "w">
+<!ENTITY SubscribeToNewsgroup.label "Tanysgrifio i Grŵp Newyddion">
+<!ENTITY SubscribeToNewsgroup.accesskey "N">
+<!ENTITY SendMessageTo.label "Ysgrifennu Neges At">
+<!ENTITY SendMessageTo.accesskey "Y">
+<!ENTITY CopyEmailAddress.label "Copïo Cyfeiriad E-bost">
+<!ENTITY CopyEmailAddress.accesskey "C">
+<!ENTITY CopyNameAndEmailAddress.label "Copïo Enw a Chyfeiriad E-bost">
+<!ENTITY CopyNameAndEmailAddress.accesskey "E">
+<!ENTITY CopyNewsgroupName.label "Copïo Enw Grŵp Newyddion">
+<!ENTITY CopyNewsgroupName.accesskey "N">
+<!ENTITY CopyNewsgroupURL.label "Copïo URL Grŵp Newyddion">
+<!ENTITY CopyNewsgroupURL.accesskey "U">
+<!ENTITY CreateFilterFrom.label "Creu Hidl o…">
+<!ENTITY CreateFilterFrom.accesskey "H">
+<!ENTITY reportPhishingURL.label "Adrodd ar Dwyll E-bost">
+<!ENTITY reportPhishingURL.accesskey "A">
+
+<!-- Spell checker context menu items -->
+<!ENTITY spellAddDictionaries.label "Ychwanegu Geiriaduron…">
+<!ENTITY spellAddDictionaries.accesskey "Y">
+
+<!-- Content Pane Context Menu -->
+<!ENTITY saveLinkAsCmd.label "Cadw Dolen Fel…">
+<!ENTITY saveLinkAsCmd.accesskey "D">
+<!ENTITY saveImageAsCmd.label "Cadw Delwedd Fel…">
+<!ENTITY saveImageAsCmd.accesskey "D">
+<!ENTITY copyLinkCmd.label "Copïo Lleoliad Dolen">
+<!ENTITY copyLinkCmd.accesskey "C">
+<!ENTITY copyImageAllCmd.label "Copïo Delwedd">
+<!ENTITY copyImageAllCmd.accesskey "p">
+<!ENTITY copyEmailCmd.label "Copïo Cyfeiriad E-bost">
+<!ENTITY copyEmailCmd.accesskey "E">
+<!ENTITY stopCmd.label "Atal">
+<!ENTITY stopCmd.accesskey "A">
+<!ENTITY reloadCmd.label "Ail-lwytho">
+<!ENTITY reloadCmd.accesskey "A">
+<!ENTITY openInBrowser.label "Agor yn y Porwr">
+<!ENTITY openInBrowser.accesskey "A">
+<!ENTITY openLinkInBrowser.label "Agor Dolen yn y Porwr">
+<!ENTITY openLinkInBrowser.accesskey "D">
+
+<!-- Statusbar -->
+<!ENTITY statusText.label "Gorffen">
+
+<!-- Mac OS X Window Menu -->
+<!ENTITY minimizeWindow.label "Lleihau">
+<!ENTITY minimizeWindow.key "m">
+<!ENTITY bringAllToFront.label "Dwyn y Cyfan i'r Blaen">
+<!ENTITY zoomWindow.label "Chwyddo">
+
+<!-- Mac OS X Application Menu (Cocoa widgets) -->
+<!ENTITY preferencesCmdMac2.label       "Dewisiadau">
+<!ENTITY preferencesCmdMac.commandkey   ",">
+<!ENTITY preferencesCmdMac.modifiers    "accel">
+<!ENTITY servicesMenuMac.label          "Gwasanaethau">
+<!ENTITY hideThisAppCmdMac.label        "Cuddio &brandShortName;">
+<!ENTITY hideThisAppCmdMac.commandkey   "H">
+<!ENTITY hideThisAppCmdMac.modifiers    "accel">
+<!ENTITY hideOtherAppsCmdMac.label      "Cuddio Eraill">
+<!ENTITY hideOtherAppsCmdMac.commandkey "E">
+<!ENTITY hideOtherAppsCmdMac.modifiers  "accel,alt">
+<!ENTITY showAllAppsCmdMac.label        "Dangos Popeth">
+
+<!-- Mac OS X Dock Icon pop-up menu -->
+<!ENTITY dockOptions.label              "Dewisiadau Eicon Ap…">
+<!ENTITY writeNewMessageDock.label      "Ysgrifennu Neges Newydd">
+<!ENTITY openAddressBookDock.label      "Agor y Llyfr Cyfeiriadau">
+
+<!-- Content tab Navigation buttons -->
+<!ENTITY browseBackButton.tooltip    "Nôl un tudalen">
+<!ENTITY browseForwardButton.tooltip "Mynd ymlaen un tudalen">
diff --git a/l10n-cy/mail/chrome/messenger/messenger.properties b/l10n-cy/mail/chrome/messenger/messenger.properties
new file mode 100644
index 0000000000..83621f0937
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messenger.properties
@@ -0,0 +1,797 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The following are used by the messenger application
+#
+
+# LOCALIZATION NOTE(statusMessage):
+# Do not translate the words %1$S and %2$S below. Place the word %1$S where the
+# account name should appear and %2$S where the status message should appear.
+# EXAMPLE: Jim's Account: Downloading messages...
+statusMessage=%1$S: %2$S
+
+removeAccount=Dileu Cyfrif…
+newFolderMenuItem=Ffolder…
+newSubfolderMenuItem=Is-ffolder…
+newFolder=Ffolder Newydd…
+newSubfolder=Is ffolder Newydd…
+markFolderRead=Marcio Ffolder wedi'i Darllen;Marcio Ffolderi wedi'u Darllen
+markNewsgroupRead=Marcio Grŵp Newyddion wedi'i Darllen; Marcio Grwpiau Newyddion wedi'u Darllen
+folderProperties=Priodweddau Ffolderi
+newTag=Tag Newydd…
+# LOCALIZATION NOTE (getNextNewsMessages): Semi-colon list of plural forms.
+# #1 is the number of news messages to get.
+getNextNewsMessages=Estyn y #1 Neges Newyddion Nesaf;Estyn y #1 Neges Newyddion Nesaf
+advanceNextPrompt=Ymlaen i'r neges nesaf heb ei darllen yn %S?
+titleNewsPreHost=ar
+replyToSender=Ateb i'r Anfonwr
+reply=Ateb
+EMLFiles=Ffeiliau E-bost
+OpenEMLFiles=Agor Neges
+# LOCALIZATION NOTE(defaultSaveMessageAsFileName): Do not translate ".eml"
+# in the line below. Also, the complete file name should be 8.3.
+defaultSaveMessageAsFileName=message.eml
+# LOCALIZATION NOTE(longMsgSubjectTruncator): A suffix string appended to the filename
+# (created from message subject) if it needed to be truncated due to length.
+longMsgSubjectTruncator=...
+SaveMailAs=Cadw Neges Fel
+SaveAttachment=Cadw Atodiad
+SaveAllAttachments=Cadw Pob atodiad
+DetachAttachment=Datod Atodiad
+DetachAllAttachments=Datod Pob Atodiad
+ChooseFolder=Dewis Ffolder
+LoadingMessageToPrint=Llwytho neges i'w hargraffu…
+MessageLoaded=Neges wedi'i llwytho…
+PrintingMessage=Argraffu'r neges…
+PrintPreviewMessage=Neges Rhagolwg cyn Argraffu…
+PrintingContact=Argraffu cysylltiad…
+PrintPreviewContact=Argraffu Rhagolwg cysylltiad…
+PrintingAddrBook=Argraffu'r Llyfr Cyfeiriadau…
+PrintPreviewAddrBook=Rhagolwg Argraffu'r Llyfr Cyfeiriadau…
+PrintingComplete=Gorffen.
+PreviewTitle=%S - %S
+LoadingMailMsgForPrint=(Llwytho'r cynnwys ar gyfer Argraffu)
+LoadingMailMsgForPrintPreview=(Llwytho'r cynnwys ar gyfer Rhagolwg Argraffu)
+saveAttachmentFailed=Methu cadw'r atodiad. Gwiriwch enw eich ffeil a cheisiwch eto yn ddiweddarach.
+saveMessageFailed=Methu cadw'r neges. Gwirio enw'r ffeil a cheisio eto yn ddiweddarach.
+fileExists=Mae %S yn bodoli yn barod. Hoffech chi newid y ffeil?
+# LOCALIZATION NOTE(failedToReadFile): %1$S is replaced by the file name, %2$S is replaced by the reason the file load failed.
+failedToReadFile=Methu darllen ffeil : %1$S rheswm: %2$S
+
+downloadingNewsgroups=Llwytho Grwpiau Newyddion ar gyfer Defnydd All-lein
+downloadingMail=Llwytho E-bost i lawr ar gyfer Defnydd All-lein
+sendingUnsent=Anfon Negeseuon sydd Heb eu Hanfon
+
+folderExists=Mae ffolder gyda'r enw hwnnw'n bodoli eisoes. Rhowch enw arall arno.
+# LOCALIZATION NOTE(confirmDuplicateFolderRename): %1$S is name of folder being moved, %2$S is parent folder name, %3$S is proposed new folder name
+confirmDuplicateFolderRename=Mae is-ffolder gyda'r enw '%1$S' yn bodoli yn ffolder '%2$S'. Hoffech chi symud y ffolder hwn gan ddefnyddio'r enw newydd '%3$S'?
+folderCreationFailed=Methu creu'r ffolder oherwydd bod y ffolder dewiswyd yn cynnwys nod anhysbys. Rhowch enw arall a cheisiwch eto.
+
+compactingFolder=Cywasgu ffolder %S…
+# LOCALIZATION NOTE(compactingDone): %1$S is the compaction gain.
+compactingDone=Wedi cwblhau cywasgu (tua %1$S wedi ei ryddhau).
+autoCompactAllFoldersTitle=Cywasgu'r Ffolderi
+
+# LOCALIZATION NOTE(autoCompactAllFoldersMsg): %1$S will be replaced by size gain of the compaction (including the unit), %2$S will be replaced by application name
+autoCompactAllFoldersMsg=Mae modd tynnu'r negeseuon rydych chi wedi'u dileu o'r ddisg. Bydd y weithred hon yn arbed tua %1$S o le ar y ddisg. Dewiswch yr opsiwn isod i adael i %2$S wneud hyn yn awtomatig heb ofyn i chi.
+autoCompactNeverAskCheckbox=Tynnu negeseuon wedi eu dileu'n awtomatig a pheidio â gofyn i mi.
+proceedButton=&Parhau
+
+confirmFolderDeletionForFilter=Bydd dileu ffolder '%S' yn analluogi'r hidl(au) cysylltiedig. Ydych chi'n siŵr eich bod chi eisiau dileu'r ffolder?
+alertFilterChanged=Bydd yr hidlau sy'n gysylltiedig â'r ffolder yn cael ei ddiweddaru.
+filterDisabled=Nid oedd modd dod o hyn i ffolder '%S', felly bydd ffolder(i) sy'n gysylltiedig a'r ffolder yn cael eu hanalluogi. Gwiriwch fod y ffolder yn bodoli a bod yr hidlau yn cyfeirio at ffolder cyrchfan gwirioneddol.
+filterFolderDeniedLocked=Nid oedd modd hidlo'r negeseuon i ffolder '%S' gan fod gweithred arall ar waith.
+parsingFolderFailed=Methu agor ffolder %S gan ei fod yn cael ei ddefnyddio gan weithred arall. Arhoswch i'r weithred ddod i ben ac yna dewis y ffolder eto.
+deletingMsgsFailed=Methu dileu negeseuon yn ffolder %S gan ei fod yn cael ei ddefnyddio gan weithred arall. Arhoswch i'r weithred ddod i ben ac yna ceisio eto.
+alertFilterCheckbox=Peidiwch rhybuddio fi eto.
+compactFolderDeniedLock=Nid oes modd cywasgu ffolder '%S' oherwydd bod gweithred arall ar waith. Ceisiwch eto yn ddiweddarach.
+compactFolderWriteFailed=Nid oedd modd cywasgu ffolder '%S' oherwydd methodd ysgrifennu i ffolder. Gwiriwch fod gennych ddigon o le ar ddisg, a bod gennych hawl ysgrifennu i'r system ffeiliau, ac yna ceisiwch eto.
+compactFolderInsufficientSpace=Nid oes modd cywasgu rhai ffolderi (e.e. '%S') gan nad oes digon o le ar ddisg. Dilëwch rhai ffeiliau a cheisiwch eto.
+filterFolderHdrAddFailed=Nid oedd modd hidlo ffolder '%S' oherwydd methodd ychwanegu neges ato. Gwiriwch fod fod y ffolder yn ymddangos yn iawn neu ceisiwch ei drwsio drwy briodweddau'r ffolder.
+filterFolderWriteFailed=Nid oedd modd i'r negeseuon gael eu hidlo i ffolder '%S' oherwydd i ysgrifennu i ffolder fethu. Gwiriwch fod gennych ddigon o le ar eich disg, a bod gennych hawl ysgrifennu i'r system ffeil, yna ceisiwch eto.
+copyMsgWriteFailed=Nid oedd modd symud na chopïo negeseuon i ffolder '%S' am i ysgrifennu i'r ffolder fethu. I gynyddu lle ar ddisg, o'r ddewislen Ffeil, yn gyntaf dewiswch Gwagio'r Sbwriel, yna dewis Cywasgu Ffolderi a wedyn ceisio eto.
+cantMoveMsgWOBodyOffline=Tra'n gweithio all-lein, nid oes modd symud na chopïo negeseuon nad ydynt wedi'u llwytho i lawr ar gyfer defnydd all-lein. O'r ffenestr E-bost, agorwch ddewislen Ffeil, dewis All-lein, yna Gweithio All-lein, a cheisio eto.
+operationFailedFolderBusy=Methodd y weithred am fod gweithred arall yn defnyddio'r ffolder. Arhoswch i'r weithred honno orffen a cheisiwch eto.
+folderRenameFailed=Nid oedd modd ailenwi'r ffolder. Efallai fod y ffolder yn cael ei ailddosrannu, neu nid yw'r enw newydd yn enw ffolder dilys.
+# LOCALIZATION NOTE(verboseFolderFormat): %1$S is folder name, %2$S is server name
+verboseFolderFormat=%1$S ar %2$S
+# LOCALIZATION NOTE(filterFolderTruncateFailed): %1$S is replaced by the folder name, %2$S is replaced by the brandShortName
+filterFolderTruncateFailed=Bu gwall wrth docio'r Blwch Derbyn ar ôl hidlo neges yn ffolder '%1$S'. Efallai bydd rhaid i chi gau %2$S a dileu INBOX.msf.
+
+mailboxTooLarge=Mae ffolder %S yn llawn ac yn methu dal rhagor. I wneud lle am ragor, dilëwch unrhyw negeseuon hen neu ddiangen a chywasgu'r ffolder.
+outOfDiskSpace=Does dim digon o le ar ddisg i lwytho eich negeseuon i lawr. Dilëwch hen bost, gwagio ffolder Sbwriel a chywasgu eich ffolderi e-bost, ac yna ceisiwch eto.
+errorGettingDB=Methu agor ffeil crynodeb %S. Efallai bod gwall ar y disg, neu fod y llwybr llawn yn rhy hir.
+defaultServerTag=(Rhagosodiad)
+
+# Used in message database list view to provide a text value for graphic based cells.
+messageUnread=Heb eu Darllen
+messageHasFlag=Serennog
+messageHasAttachment=Atodiad Ynghlwm
+messageJunk=Sbam
+messageExpanded=Estynnwyd
+messageCollapsed=Caeedig
+
+# Used in the SMTP Account Settings panel when a server value has no properties
+smtpServerList-NotSpecified=<not specified>
+smtpServer-ConnectionSecurityType-0=Dim
+smtpServer-ConnectionSecurityType-1=STARTTLS, os ar gael
+smtpServer-ConnectionSecurityType-2=STARTTLS
+smtpServer-ConnectionSecurityType-3=SSL/TLS
+smtpServers-confirmServerDeletionTitle=Dileu'r Gweinydd
+smtpServers-confirmServerDeletion=Ydych chi'n siŵr eich bod am ddileu gweinydd: \n %S?
+
+# Account Settings - Both Incoming and SMTP server
+authNo=Dim dilysiad
+authOld=Cyfrinair, dull gwreiddiol (anniogel)
+authPasswordCleartextInsecurely=Cyfrinair, wedi'i drosglwyddo'n anniogel
+authPasswordCleartextViaSSL=Cyfrinair arferol
+authPasswordEncrypted=Cyfrinair wedi'i amgryptio
+authKerberos=Kerberos / GSSAPI
+authExternal=Tystysgrif TLS
+authNTLM=NTLM
+authOAuth2=OAuth2
+authAnySecure=Unrhyw ddull diogel (anghymeradwy)
+authAny=Unrhyw ddull (anniogel)
+
+# OAuth2 window title
+# LOCALIZATION NOTE(oauth2WindowTitle):
+# %1$S is the username (or full email address) used for authentication.
+# %2$S is the hostname of the account being authenticated.
+oauth2WindowTitle=Rhowch fanylion %1$S ar %2$S
+
+# LOCALIZATION NOTE(serverType-nntp): Do not translate "NNTP" in the line below
+serverType-nntp=Gweinydd Newyddion (NNTP)
+# LOCALIZATION NOTE(serverType-pop3): Do not translate "POP" in the line below
+serverType-pop3=Gweinydd E-bost POP
+# LOCALIZATION NOTE(serverType-imap): Do not translate "IMAP" in the line below
+serverType-imap=Gweinydd E-bost IMAP
+serverType-none=Storfa E-bost Lleol
+# LOCALIZATION NOTE(serverType-movemail): DONT_TRANSLATE
+serverType-movemail=Unix Movemail
+
+sizeColumnTooltip2=Trefnu yn ôl maint
+sizeColumnHeader=Maint
+linesColumnTooltip2=Trefnu yn ôl llinellau
+linesColumnHeader=Llinellau
+
+# LOCALIZATION NOTE (getMsgButtonTooltip): Do not translate the word "%S" below.
+# Place the word "%S" in your translation where the name of the comma separated accounts should appear.
+getMsgButtonTooltip=Estyn negeseuon ar gyfer %S
+# Used to separate email addresses in a list.  Note the trailing space ', '
+getMsgButtonTooltip.listSeparator=,\u0020
+
+# status feedback stuff
+documentDone=
+documentLoading=Llwytho Neges…
+
+# LOCALIZATION NOTE (autosyncProgress): Do not translate the word "%1$S" or "%2$S" below.
+# Place the word %1$S in your translation where the name of the comma separated folders should appear.
+# Place the word %2$S in your translation where the name of the comma separated accounts should appear.
+autosyncProgress=Cydweddu negeseuon yn %1$S o %2$S…
+
+unreadMsgStatus=Heb eu darllen: %S
+selectedMsgStatus=Dewiswyd:%S
+totalMsgStatus=Cyfanswm: %S
+
+# localized folder names
+
+localFolders=Ffolderi Lleol
+
+# LOCALIZATION NOTE (inboxFolderName): OK to translate all foldernames, bugzilla #57440 & bugzilla #23625 fixed
+inboxFolderName=Blwch Derbyn
+trashFolderName=Sbwriel
+sentFolderName=Anfonwyd
+draftsFolderName=Drafftiau
+templatesFolderName=Templedi
+outboxFolderName=Blwch Anfon
+junkFolderName=Sbam
+archivesFolderName=Archifau
+
+# "Normal" priority is often blank,
+# depending on the consumers of these strings
+priorityLowest=Isaf
+priorityLow=Isel
+priorityNormal=Arferol
+priorityHigh=Uchel
+priorityHighest=Uchaf
+
+#Group by date thread pane titles
+today=Heddiw
+yesterday=Ddoe
+lastWeek=Wythnos Diwethaf
+last7Days=7 Diwrnod Diwethaf
+twoWeeksAgo=Pythefnos yn Ôl
+last14Days=14 Diwrnod Diwethaf
+older=Hŷn
+futureDate=Y Dyfodol
+
+#Grouped By Tags
+untaggedMessages=Negeseuon heb eu Tagio
+
+# Grouped by status
+messagesWithNoStatus=Dim Statws
+
+#Grouped by priority
+noPriority=Dim Blaenoriaeth
+
+#Grouped by has attachments
+noAttachments=Dim Atodiad
+attachments=Atodiadau
+
+#Grouped by starred
+notFlagged=Dim Serenog
+groupFlagged=Serennog
+
+# defaults descriptions for tag prefs listed in mailnews.js
+# (we keep the .labels. names for backwards compatibility)
+mailnews.tags.remove=Tynnu Pob Tag
+mailnews.labels.description.1=Pwysig
+mailnews.labels.description.2=Gwaith
+mailnews.labels.description.3=Personol
+mailnews.labels.description.4=I'w Gwneud
+mailnews.labels.description.5=Diweddarach
+
+# Format definition tag menu texts.
+# This is necessary in order to get the accesskeys to be the on the first
+# character of the menu text instead of after the menu text.
+# If a key definition exists for the tag at index n, that key's key will be
+# taken as the accesskey, eg.
+#   <key id="key_tag3" key="&tagCmd3.key;" oncommand="ToggleMessageTagKey(3);"/>
+# makes the third tag have the accesskey &tagCmd3.key;.
+# In the menuitem's label, this accesskey appears at %1$S below; %2$S will be
+# replaced by the tag label.
+mailnews.tags.format=%1$S %2$S
+
+replied=Atebwyd
+forwarded=Anfonwyd Ymlaen
+new=Newydd
+read=Darllenwyd
+flagged=Serennog
+
+# for junk status picker in search and mail views
+junk=Sbam
+
+# for junk score origin picker in search and mail views
+junkScoreOriginPlugin=Ategyn
+junkScoreOriginFilter=Hidl
+junkScoreOriginWhitelist=Rhestr Wen
+junkScoreOriginUser=Defnyddiwr
+junkScoreOriginImapFlag=Baner IMAP
+
+# for the has attachment picker in search and mail views
+hasAttachments=Atodiadau Ynghlwm
+
+# for the Tag picker in search and mail views.
+tag=Tagiau
+
+# LOCALIZATION NOTE(andOthers):
+# for multiple authors, add this abbreviation to the first author to indicate
+# there are more; for the From column in the threadpane message list.
+andOthers=et al.
+
+# mailnews.js
+mailnews.send_default_charset=UTF-8
+mailnews.view_default_charset=ISO-8859-1
+
+# whether to generate display names in last first order
+# LOCALIZATION NOTE(mail.addr_book.displayName.lastnamefirst):
+# the only valid values are: true OR false (choose from the untranslated English words)
+mail.addr_book.displayName.lastnamefirst=false
+
+# whether to also show phonetic fields in the addressbook
+# LOCALIZATION NOTE(mail.addr_book.show_phonetic_fields):
+# the only valid values are: true OR false (choose from the untranslated English words)
+mail.addr_book.show_phonetic_fields=false
+
+# valid format options are:
+# 1: yyyy/mm/dd
+# 2: yyyy/dd/mm
+# 3: mm/dd/yyyy
+# 4: mm/yyyy/dd
+# 5: dd/mm/yyyy
+# 6: dd/yyyy/mm
+#
+# 0: auto-detect the current locale format
+#    a separator has to be either '/', '-', '.' and the year in Christian year
+#    otherwise mm/dd/yyyy (option 3) is used
+#
+mailnews.search_date_format=0
+# separator for search date (e.g. "/", "-"), or empty when search_date_format is zero
+mailnews.search_date_separator=
+# leading zeros for day and month values, not used if mailnews.search_date_format is not zero
+mailnews.search_date_leading_zeros=true
+
+# offline msg
+nocachedbodybody2=Nid yw corff y neges wedi cael ei llwytho i lawr o'r gweinydd ar gyfer darllen all-lein. I ddarllen y neges rhaid i chi ail gysylltu â'r rhwydwaith, dewis All-lein o'r ddewislen Ffeil ac yna dad-dewis Gweithio All-lein. Yn y dyfodol, gallwch ddewis pa neges neu ffolder i'w ddarllen all-lein. I wneud hyn, dewiswch All-lein o'r ddewislen ffeil ac yna dewis Llwytho i Lawr/Cydweddu Nawr. Gallwch newid Lle ar Ddisg i atal llwytho negeseuon mawr i lawr.
+
+# LOCALIZATION NOTE(acctCentralTitleFormat): %1$S is brand, %2$S is account type, %3$S is account name
+acctCentralTitleFormat=%1$S %2$S - %3$S
+mailAcctType=E-bost
+newsAcctType=Newyddion
+feedsAcctType=Llif
+
+# LOCALIZATION NOTE(nocachedbodytitle): Do not translate "<TITLE>" or "</TITLE>" in the line below
+nocachedbodytitle=<TITLE>Ewch Ar-lein i Ddarllen y Neges Hon</TITLE>\n
+
+# mailWindowOverlay.js
+confirmUnsubscribeTitle=Cadarnhau Dad-danysgrifio
+confirmUnsubscribeText=Ydych chi'n siŵr eich bod am ddad-danysgrifio o %S?
+confirmUnsubscribeManyText=Ydych chi'n siŵr eich bod am ddad-danysgrifio o'r grwpiau newyddion hyn?
+restoreAllTabs=Adfer Pob Tab
+
+confirmMarkAllFoldersReadTitle=Marcio Pob Ffolder Wedi'u Darllen
+confirmMarkAllFoldersReadMessage=Ydych chi'n siŵr eich bod am farcio pob neges ym mhob ffolder o'r cyfrif hwn fel wedi'i darllen?
+
+# LOCALIZATION NOTE(junkBarMessage): %S is brand
+junkBarMessage=Mae %S yn meddwl mai Sbam yw'r neges hon.
+junkBarButton=Nid Sbam
+junkBarButtonKey=N
+junkBarInfoButton=Dysgu Rhagor
+junkBarInfoButtonKey=R
+
+# LOCALIZATION NOTE(remoteContentBarMessage): %S is brand
+remoteContentBarMessage=I ddiogelu eich preifatrwydd, mae %S wedi rhwystro delweddau pell yn y neges.
+remoteContentPrefLabel=Dewisiadau
+remoteContentPrefAccesskey=D
+remoteContentPrefLabelUnix=Dewisiadau
+remoteContentPrefAccesskeyUnix=D
+
+# LOCALIZATION NOTE(remoteAllowResource): %S is origin
+remoteAllowResource=Caniatáu cynnwys pell o %S
+# LOCALIZATION NOTE(remoteAllowAll): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# #1 is the number of origins
+remoteAllowAll=Peidio caniatáu cynnwys pell o'r ffy nhonnellau uchod;Caniatáu cynnwys pell o'r #1 ffynhonnell uchod;Caniatáu cynnwys pell o'r #1 ffynhonnell uchod;Caniatáu cynnwys pell o'r #1 ffynhonnell uchod;Caniatáu cynnwys pell o'r #1 ffynhonnell uchod;Caniatáu cynnwys pell o'r #1 ffynhonnell uchod
+
+phishingBarMessage=Efallai mai ffugiad yw'r neges hon.
+phishingBarPrefLabel=Dewisiadau
+phishingBarPrefAccesskey=e
+phishingBarPrefLabelUnix=Dewisiadau
+phishingBarPrefAccesskeyUnix=d
+
+mdnBarIgnoreButton=Anwybyddu'r Cais
+mdnBarIgnoreButtonKey=n
+mdnBarSendReqButton=Anfon Derbynneb
+mdnBarSendReqButtonKey=A
+
+draftMessageMsg=Neges ddrafft yw hon.
+draftMessageButton=Golygu
+draftMessageButtonKey=G
+
+# msgHdrViewOverlay.js
+openLabel=Agor
+openLabelAccesskey=O
+saveLabel=Cadw Fel…
+saveLabelAccesskey=A
+detachLabel=Datod…
+detachLabelAccesskey=D
+deleteLabel=Dileu
+deleteLabelAccesskey=E
+openFolderLabel=Agor Ffolder Cynhwysol
+openFolderLabelAccesskey=F
+deleteAttachments=Bydd yr atodiadau canlynol yn cael eu dileu'n barhaol o neges:\n%S\nNid oes modd dadwneud y weithred hon. Hoffech chi barhau?
+detachAttachments=Mae'r atodiadau canlynol wedi'u cadw'n llwyddiannus a byddant yn cael eu dileu o'r neges yn barhaol:\n%S\nNid oes modd dadwneud y weithred hon. Hoffech chi barhau?
+deleteAttachmentFailure=Methu dileu'r atodiad yma.
+emptyAttachment=Mae'r atodiad yma i weld yn wag.\nGwiriwch gyda'r person anfonodd hwn.\nYn aml mae muriau tân neu raglenni gwrth firws yn dinistrio atodiadau.
+externalAttachmentNotFound=Nid yw'r ffeil ar wahân hon neu atodiad dolen wedi ei ganfod neu nid yw'n hygyrch yn y lleoliad hwn bellach.
+
+# LOCALIZATION NOTE (attachmentCount): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# #1 number of attachments
+attachmentCount=Dim atodiadau;#1 atodiad;#1 atodiad;#1 atodiad;#1 atodiad;#1 atodiad
+
+# LOCALIZATION NOTE (attachmentCountSingle): This is the format for the
+# attachment header when a message has only one attachment. This is separate
+# from attachmentCount above, since attachmentCountSingle typically ends with a
+# colon.
+attachmentCountSingle=1 atodiad:
+
+# LOCALIZATION NOTE (attachmentSizeUnknown): The string to show for the total
+# size of all attachments when none of the attachments' sizes can be detected.
+attachmentSizeUnknown=maint anhysbys
+
+# LOCALIZATION NOTE (attachmentSizeAtLeast): The string to show for the total
+# size of all attachments when at least one (but not all) of the attachments'
+# sizes can't be detected. %1$S is the formatted size.
+attachmentSizeAtLeast=o leiaf %1$S
+
+# This is the format for prepending accesskeys to the
+# each of the attachments in the file|attachments menu:
+#   ie: 1 file.txt
+#       2 another file.txt
+attachmentDisplayNameFormat=%S %S
+
+# This is the heading for the attachment summary when printing an email
+attachmentsPrintHeader=Atodiadau:
+
+# Connection Error Messages
+# LOCALIZATION NOTE(unknownHostError): %S is the server name
+unknownHostError=Methwyd cysylltu â gweinydd %S.
+# LOCALIZATION NOTE(connectionRefusedError): %S is the server name
+connectionRefusedError=Methwyd cysylltu â gweinydd %S; gwrthodwyd y cysylltiad.
+# LOCALIZATION NOTE(netTimeoutError): %S is the server name
+netTimeoutError=Cyfnod cyswllt i weinydd %S wedi dod i ben.
+# LOCALIZATION NOTE(netResetError): %S is the server name
+netResetError=Cafodd cysylltiad â gweinydd %S ei ailosod.
+# LOCALIZATION NOTE(netInterruptError): %S is the server name
+netInterruptError=Cafodd cysylltiad â gweinydd %S ei darfu.
+
+recipientSearchCriteria=Mae'r Testun neu'r Derbynnydd yn cynnwys:
+fromSearchCriteria=Mae'r Pwnc neu'r Anfonwr yn cynnwys:
+
+# LOCALIZATION NOTE(biffNotification): %1$S is the number of new messages
+biffNotification_message=%1$S neges newydd
+biffNotification_messages=%1$S neges newydd
+
+# LOCALIZATION NOTE(newMailNotification_message): %1$S is the name of the account %2$S is the number of new messages
+newMailNotification_message=Mae %1$S wedi derbyn %2$S neges newydd
+
+# LOCALIZATION NOTE(newMailNotification_messages): %1$S is the name of the account %2$S is the number of new messages
+newMailNotification_messages=Mae %1$S wedi derbyn %2$S neges newydd
+
+# LOCALIZATION NOTE(newMailNotification_messagetitle): %1$S is subject of new message and %2$S is sender of new message.
+# This is UNIX only
+newMailNotification_messagetitle=%1$S o %2$S
+
+# LOCALIZATION NOTE(newMailAlert_message):
+# Semi-colon list of plural forms. See:
+# https://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the name of the account, #2 is the number of new messages
+newMailAlert_message=Nid yw #1 wedi derbyn negeseuon newydd;#1 wedi derbyn #2 neges newydd;#1 wedi derbyn #2 neges newydd;#1 wedi derbyn #2 neges newydd;#1 wedi derbyn #2 neges newydd;#1 wedi derbyn #2 neges newydd
+
+# LOCALIZATION NOTE(macBiffNotification is Mac only):
+#  %1$S is the number of new messages
+#  %2$S is a list of names and/or email addresses separated by biffNotification_separator
+#  %3$S is the number of new messages not displayed in the biff alert
+macBiffNotification_message=%1$S neges newydd o %2$S.
+macBiffNotification_messages=Mae gan %1$S neges newydd oddi wrth %2$S.
+macBiffNotification_messages_extra=Mae gan %1$S %2$S neges newydd %3$S yn rhagor.
+# Used to separate names/email addresses in a list.  Note the trailing space ', '
+macBiffNotification_separator=,\u0020
+
+# For the Quota tab in the mail folder properties dialog
+quotaPercentUsed=%S%% yn llawn
+# for quota in main window (commandglue.js)
+percent=%S%%
+
+quotaTooltip2=Cwota IMAP: mae %S KB wedi'i ddefnyddio allan o gyfanswm o %S KB. Cliciwch am fanylion.
+
+# for message views
+confirmViewDeleteTitle=Cadarnhau
+confirmViewDeleteMessage=Ydych chi'n siŵr eich bod am ddileu'r olwg yma?
+
+# for virtual folders
+confirmSavedSearchTitle=Cadarnhau Dileu
+confirmSavedSearchDeleteMessage=Ydych chi'n siŵr eich bod am ddileu'r chwilio a gadwyd?
+
+## @name ENTER_PASSWORD_PROMPT
+## @loc None
+# LOCALIZATION NOTE (passwordPrompt): Do not translate the word %S below.
+# Place the word "%S" in your translation where the email address
+# or the username should appear
+passwordPrompt=Rhowch gyfrinair ar gyfer %1$S ar %2$S:
+
+## @name ENTER_PASSWORD_PROMPT_TITLE
+## @loc None
+passwordTitle=Mae angen Cyfrinair gweinydd E-bost
+
+# for checking if the user really wants to open lots of messages in separate windows.
+openWindowWarningTitle=Cadarnhau
+# LOCALIZATION NOTE (openWindowWarningConfirmation): Semi-colon list of plural forms.
+# #1 is the number of messages the user is attempting to open.
+openWindowWarningConfirmation=Efallai bydd agor #1 neges yn araf. Parhau?;Efallai bydd agor #1neges yn araf. Parhau?
+
+# for checking if the user really wants to open lots of messages in tabs.
+openTabWarningTitle=Cadarnhau
+# LOCALIZATION NOTE (openTabWarningConfirmation): Semi-colon list of plural forms.
+# #1 is the number of messages the user is attempting to open.
+openTabWarningConfirmation=Efallai bydd agor #1 neges yn araf. Parhau?;Efallai bydd agor #1neges yn araf. Parhau?
+
+# for warning the user that a tag they're trying to create already exists
+tagExists=Mae tag o'r enw yna'n bodoli eisoes.
+
+# title of the edit tag dialog
+editTagTitle=Golygu Tag
+
+# for the virtual folder list dialog title
+# %S is the name of the saved search folder
+editVirtualFolderPropertiesTitle=Golygu Priodweddau Chwilio a Gadwyd ar gyfer %S
+# LOCALIZATION NOTE (foldersChosen): #1 number of chosen folders
+virtualFolderSourcesChosen=Wedi dewis #1 ffolder;Wedi dewis #1 ffolder
+
+#alert to inform the user to choose one or more folders to search for a saved search folder
+alertNoSearchFoldersSelected=Rhaid dewis o leiaf un ffolder i chwilio am y ffolder chwilio a gadwyd.
+
+# These are displayed in the message and folder pane windows
+# LOCALIZATION NOTE %.*f is the abbreviated size in the appropriate units
+byteAbbreviation2=%.*f beit
+kiloByteAbbreviation2=%.*f KB
+megaByteAbbreviation2=%.*f MB
+gigaByteAbbreviation2=%.*f GB
+
+teraByteAbbreviation2=%.*f TB
+petaByteAbbreviation2=%.*f PB
+
+## LOCALIZATION NOTE(folderWithAccount):
+## This is used to show folder name together with an account name.
+## %1$S = folder name
+## %2$S = account name
+folderWithAccount=%1$S - %2$S
+## LOCALIZATION NOTE(folderWithUnreadMsgs):
+## This is a concatenation of two strings to compose a folder label with unread messages.
+## %1$S = folder name
+## %2$S = count of unread messages
+folderWithUnreadMsgs=%1$S (%2$S)
+## LOCALIZATION NOTE(summarizedValue):
+## This string shows an indication that the value shown is actually a summary
+## accumulated from all subfolders.
+## %S = summarized value from all subfolders
+folderSummarizedSymbolValue=▾%S
+## LOCALIZATION NOTE(subfoldersExplanation):
+## This is a tooltip message shown on the values in the numeric folder pane columns.
+## %1$S = is the count of messages having the respective property, found in the folder under mouse cursor
+## %2$S = is the count of messages having the respective property, found in subfolders of the folder under mouse cursor
+subfoldersExplanation=%1$S yn y ffolder hwn, %2$S mewn isffolderi
+
+# Error message if message for a message id wasn't found
+errorOpenMessageForMessageIdTitle=Gwall wrth agor message-id
+errorOpenMessageForMessageIdMessage=Heb ganfod message-id %S
+
+# Warnings to alert users about phishing urls
+confirmPhishingTitle=Rhybudd E-bost Twyllodrus
+linkMismatchTitle=Wedi canfod Dolenni Anghydweddus
+#LOCALIZATION NOTE %1$S is the brand name, %2$S is the host name of the url being visited
+confirmPhishingUrl=Mae %1$S yn meddwl mai twyll yw'r neges hon. Gall fod y dolenni yn ceisio efelychu tudalennau gwe rydych am ymweld â nhw. Ydych chi'n siŵr eich bod am ymweld â %2$S?
+#LOCALIZATION NOTE %1$S is the host name of indicated host, %2$S is the host name of the actual host.
+confirmPhishingUrlAlternate=Mae'n ymddangos bod y ddolen rydych newydd glicio arni yn mynd i at wefan gwahanol i'r hyn mae testun y ddolen yn ei ddangos. Weithiau mae hyn yn cael ei defnyddio i dracio a ydych wedi clicio ar y ddolen, ond gall hefyd fod yn sgam.\n\n Mae testun y ddolen yn awgrymu fod y ddolen yn mynd i %1$S, ond i %2$S mae'n mynd.
+#LOCALIZATION NOTE $1$S is the host name of the indicated host.
+confirmPhishingGoAhead=Mynd i %1$S beth bynnag
+#LOCALIZATION NOTE %1$S is the host name that was displayed to the user.
+confirmPhishingGoDirect=Mynd i %1$S
+
+# Check for Updates
+# LOCALIZATION NOTE (updatesItem_*): these are alternative labels for Check for Update item in Help menu.
+# Which one is used depends on Update process state.
+updatesItem_default=Gwirio am Ddiweddariadau…
+updatesItem_defaultFallback=Gwirio am Ddiweddariadau…
+updatesItem_default.accesskey=G
+updatesItem_downloading=Llwytho %S i Lawr…
+updatesItem_downloadingFallback=Llwytho'r Diweddariad i Lawr…
+updatesItem_downloading.accesskey=L
+updatesItem_resume=Ail-ddechrau Llwytho %S i Lawr…
+updatesItem_resumeFallback=Ail-ddechrau Llwytho'r Diweddariad i Lawr…
+updatesItem_resume.accesskey=A
+updatesItem_pending=Gosod y Diweddariad Nawr…
+updatesItem_pendingFallback=Gosod y Diweddariad Nawr…
+updatesItem_pending.accesskey=G
+
+# Folder Pane Header Title Strings
+folderPaneModeHeader_all=Pob Ffolder
+folderPaneModeHeader_unread=Ffolderi Heb eu Darllen
+folderPaneModeHeader_unread_compact=Ffolderi heb eu Darllen - Golwg Cryno
+folderPaneModeHeader_favorite=Hoff Ffolderi
+folderPaneModeHeader_favorite_compact=Hoff Ffolderi - Golwg Cryno
+folderPaneModeHeader_recent=Ffolderi Diweddar
+folderPaneModeHeader_recent_compact=Ffolderi Diweddar - Golwg Cryno
+folderPaneModeHeader_smart=Ffolderi a Unwyd
+unifiedAccountName=Ffolderi a Unwyd
+
+# Copy / Move to Folder Again
+#LOCALIZATION NOTE %1$S is the name of the folder we will move to. moveToFolderAgainAccessKey
+# should have the same value as copyToFolderAgainAccessKey as they are the same menu item in the UI
+# moveToFolderAgainAccessKey should also be a letter that occurs before %1$S
+moveToFolderAgain=Symud i "%1$S" Eto
+moveToFolderAgainAccessKey=t
+#LOCALIZATION NOTE %1$S is the name of the folder we will copy to
+# copyToFolderAgainAccessKey
+# should have the same value as moveToFolderAgainAccessKey as they are the same menu item in the UI
+# copyToFolderAgainAccessKey should also be a letter that occurs before %1$S
+copyToFolderAgain=Copïo i "%1$S" Eto
+copyToFolderAgainAccessKey=t
+
+#LOCALIZATION NOTE(mdnBarMessageNormal) %1$S is the name of the sender
+mdnBarMessageNormal=Mae %1$S wedi gofyn i gael ei hysbysu pan fyddwch wedi darllen y neges.
+#LOCALIZATION NOTE(mdnBarMessageAddressDiffers) %1$S is the name of the sender, %2$S is the address(es) to send return receipt to
+mdnBarMessageAddressDiffers=Mae %1$S wedi gofyn i gael ei hysbysu (ar %2$S) pan fyddwch wedi darllen y neges.
+
+# mailCommands.js
+emptyJunkFolderTitle=Gwagio "%S"
+emptyJunkFolderMessage=Dileu pob neges ac is-ffolder yn y ffolder Sbam?
+emptyJunkDontAsk=Peidiwch gofyn i mi eto.
+emptyTrashFolderTitle=Gwagio "%S"
+emptyTrashFolderMessage=Dileu pob neges ac is-ffolder yn y ffolder Sbwriel?
+emptyTrashDontAsk=Peidiwch gofyn i mi eto.
+
+# junkCommands.js
+junkAnalysisPercentComplete=Dadansoddi sbam, cwblhau %S
+processingJunkMessages=Prosesu Negeseuon Sbam
+
+# Messenger bootstrapping messages
+fileNotFoundTitle = Heb Ganfod Ffeil
+#LOCALIZATION NOTE(fileNotFoundMsg): %S is the filename
+fileNotFoundMsg = Nid yw ffeil %S yn bodoli.
+
+fileEmptyTitle = Ffeil Gwag
+#LOCALIZATION NOTE(fileEmptyMsg): %S is the filename
+fileEmptyMsg = Mae ffeil %S yn wag.
+
+# LOCALIZATION NOTE (headerMoreAddrs): semicolon separated list of plural
+# forms of the word "more" as used after the number of addresses
+# currently hidden while displaying a header such as "to", "cc", or "bcc"
+# in the message header box.  English has two identical forms here, so it will
+# construct strings that look like (for example) "1 more" or "20 more".
+# <https://developer.mozilla.org/en/Localization_and_Plurals> has details
+# on this mechanism.
+headerMoreAddrs=Dim yn rhagor;#1 yn rhagor;#1 yn rhagor;#1 yn rhagor;#1 yn rhagor;#1 yn rhagor
+
+# LOCALIZATION NOTE (headerMoreAddrsTooltip): semicolon separated list of
+# plural forms of the phrase ", and #1 more" as used in the tooltip text
+# of the more widget displayed in the header pane (see headerMoreAddrs).
+# English has two identical forms here, so it will construct strings that
+# look like (for example) ", and 1 more" or ", and 20 more".
+# <https://developer.mozilla.org/en/Localization_and_Plurals> has details
+# on this mechanism.
+headerMoreAddrsTooltip=, a dim yn rhagor;, a #1 yn rhagor;, a #1 yn rhagor;, a #1 yn rhagor;, a #1 yn rhagor;, a #1 yn rhagor
+
+# LOCALIZATION NOTE (headertoFieldMe): first person prepositional object
+# pronoun used in the "to" header of the message header pane.  This is also
+# used for the fallback case if a header-specific localization is not
+# available.
+headertoFieldMe=Fi
+
+# LOCALIZATION NOTE (headerfromFieldMe): first person prepositional object
+# pronoun used in the "from" header of the message header pane.
+headerfromFieldMe=Fi
+
+# LOCALIZATION NOTE (headerreply-toFieldMe): first person prepositional
+# object pronoun used in the "reply-to" header of the message header pane.
+headerreply-toFieldMe=Fi
+
+# LOCALIZATION NOTE (headerccFieldMe): first person prepositional object
+# pronoun used in the "cc" header of the message header pane.
+headerccFieldMe=Fi
+
+# LOCALIZATION NOTE (headerbccFieldMe): first person prepositional object
+# pronoun used in the "bcc" header of the message header pane.
+headerbccFieldMe=Fi
+
+expandAttachmentPaneTooltip=Dangos y paen atodiad
+collapseAttachmentPaneTooltip=Cuddio'r paen atodiad
+
+# Shown when content tabs are being loaded.
+loadingTab=Llwytho…
+
+confirmMsgDelete.title=Cadarnhau Dileu
+confirmMsgDelete.collapsed.desc=Bydd hyn yn dileu negeseuon mewn edafedd caeedig. Ydych chi'n siŵr eich bod am barhau?
+confirmMsgDelete.deleteNoTrash.desc=Bydd hwn yn cael ei ddileu'n syth, heb gadw copi i'r Sbwriel. Ydych chi'n siŵr eich bod am barhau?
+confirmMsgDelete.deleteFromTrash.desc=Bydd hyn yn dileu'r neges yn barhaol o'r Sbwriel. Hoffech chi barhau?
+confirmMsgDelete.dontAsk.label=Peidiwch gofyn i mi eto.
+confirmMsgDelete.delete.label=Dileu
+
+mailServerLoginFailedTitle=Methodd Mewngofndi
+# LOCALIZATION NOTE (mailServerLoginFailedTitleWithAccount):
+# "%S" is the account name.
+mailServerLoginFailedTitleWithAccount=Methodd mewngofnodi i gyfrif "%S"
+# LOCALIZATION NOTE (mailServerLoginFailed2):
+# %1$S is the host name of the server, %2$S is the user name.
+mailServerLoginFailed2=Methodd mewngofnodi i weinydd %1$S gydag enw defnyddiwr %2$S.
+mailServerLoginFailedRetryButton=&Ceisio eto
+mailServerLoginFailedEnterNewPasswordButton=&Cynnig Cyfrinair Newydd
+
+# LOCALIZATION NOTE (threadPane.columnPicker.confirmFolder.noChildren.title):
+# When the user selects a folder to apply the currently displayed columns to
+# via the "columnPicker.applyToFolder.label" menu option, this is the title of
+# the confirmation dialog used to verify they selected the correct folder.  This
+# is the case in which we apply the columns only to the folder and not to any of
+# its children.
+threadPane.columnPicker.confirmFolder.noChildren.title=Gosod y Newidiadau?
+# LOCALIZATION NOTE (threadPane.columnPicker.confirmFolder.noChildren.message):
+# When the user selects a folder to apply the currently displayed columns to
+# via the "columnPicker.applyToFolder.label" menu option, this is the text of
+# the confirmation dialog used to verify they selected the correct folder.  The
+# string '%S' is replaced with the name of the folder the user selected in
+# order to help them confirm they picked what they thought they picked.  This
+# is the case in which we apply the columns only to the folder and not to any of
+# its children.
+threadPane.columnPicker.confirmFolder.noChildren.message=Gosod colofnau cyfredol y ffolder i %S?
+
+# LOCALIZATION NOTE (threadPane.columnPicker.confirmFolder.withChildren.title):
+# When the user selects a folder to apply the currently displayed columns to via
+# the "columnPicker.applyToFolderAndChildren.label" menu option, this is the
+# title of the confirmation dialog used to verify they selected the correct
+# folder.  This is the case in which we apply the columns to the folder and all
+# of its children.
+threadPane.columnPicker.confirmFolder.withChildren.title=Gosod y Newidiadau?
+# LOCALIZATION NOTE (threadPane.columnPicker.confirmFolder.withChildren.message):
+# When the user selects a folder to apply the currently displayed columns to via
+# the "columnPicker.applyToFolderAndChildren.label" menu option, this is the
+# text of the confirmation dialog used to verify they selected the correct
+# folder.  The string '%S' is replaced with the name of the folder the user
+# selected in order to help them confirm they picked what they thought they
+# picked.  This is the case in which we apply the columns to the folder and all
+# of its children.
+threadPane.columnPicker.confirmFolder.withChildren.message=Gosod colofnau'r ffolder gyfredol i %S a'i blant?
+
+# LOCALIZATION NOTE (lwthemeInstallRequest.message): %S will be replaced with
+# the host name of the site.
+lwthemeInstallRequest.message=Mae gwefan (%S) wedi ceisio gosod thema.
+lwthemeInstallRequest.allowButton=Caniatáu
+lwthemeInstallRequest.allowButton.accesskey=n
+
+lwthemePostInstallNotification.message=Mae thema newydd wedi'i gosod.
+lwthemePostInstallNotification.undoButton=Dadwneud
+lwthemePostInstallNotification.undoButton.accesskey=U
+lwthemePostInstallNotification.manageButton=Rheoli Themâu…
+lwthemePostInstallNotification.manageButton.accesskey=R
+
+# safeModeRestart
+safeModeRestartPromptTitle=Ailgychwyn gyda'r Ychwanegyn wedi'i Analluogi
+safeModeRestartPromptMessage=Ydych chi'n siŵr eich bod am analluogi pob ychwanegyn ac ailgychwyn?
+safeModeRestartButton=Ailgychwyn
+
+# LOCALIZATION NOTE (downloadAndInstallButton.label): %S is replaced by the
+# version of the update: "Update to 28.0".
+update.downloadAndInstallButton.label=Diweddaru i %S
+update.downloadAndInstallButton.accesskey=D
+
+# Sanitize
+# LOCALIZATION NOTE (sanitizeDialog2.everything.title): When "Time range to
+# clear" is set to "Everything", the Clear Recent History dialog's title is
+# changed to this.  See UI mockup and comment 11 at bug 480169 -->
+sanitizeDialog2.everything.title=Clirio'r Holl Hanes
+sanitizeButtonOK=Clirio Nawr
+# LOCALIZATION NOTE (sanitizeEverythingWarning2): Warning that appears when
+# "Time range to clear" is set to "Everything" in Clear Recent History dialog,
+# provided that the user has not modified the default set of history items to clear.
+sanitizeEverythingWarning2=Bydd yr holl hanes yn cael ei glirio.
+# LOCALIZATION NOTE (sanitizeSelectedWarning): Warning that appears when
+# "Time range to clear" is set to "Everything" in Clear Recent History dialog,
+# provided that the user has modified the default set of history items to clear.
+sanitizeSelectedWarning=Bydd yr holl eitemau a ddewiswyd yn cael eu clirio.
+
+learnMoreAboutIgnoreThread=Dysgu Rhagor…
+learnMoreAboutIgnoreThreadAccessKey = S
+undoIgnoreThread=Dadwneud Anwybyddu Edefyn
+undoIgnoreThreadAccessKey=U
+undoIgnoreSubthread=Dadwneud Anwybyddu Isedefyn
+undoIgnoreSubthreadAccessKey=U
+# LOCALIZATION NOTE (ignoredThreadFeedback): #1 is the message thread title
+ignoredThreadFeedback=Ni fydd atebion i edefyn "#1" yn cael eu dangos.
+# LOCALIZATION NOTE (ignoredSubthreadFeedback): #1 is the message subthread title
+ignoredSubthreadFeedback=Ni fydd atebion i is drywydd "#1" yn cael eu dangos.
+# LOCALIZATION NOTE (ignoredThreadsFeedback): Semi-colon list of plural forms.
+# #1 is the number of threads
+ignoredThreadsFeedback=Ni fydd atebion i'r trywydd dangoswyd yn cael eu dangos.;Ni fydd atebion i'r #1 trywydd dangoswyd yn cael eu dangos.
+# LOCALIZATION NOTE (ignoredSubthreadsFeedback): Semi-colon list of plural forms.
+# #1 is number of subthreads
+ignoredSubthreadsFeedback=Ni fydd atebion i'r trywydd dangoswyd yn cael eu dangos.;Ni fydd atebion i'r #1 trywydd dangoswyd yn cael eu dangos.
+# LOCALIZATION NOTE (saveAsType): replace %S with the extension of the file to be saved.
+saveAsType=Ffeil %S
+
+# LOCALIZATION NOTE (openSearch.label): The label used in the autocomplete
+# widget to refer to a search on the web for a short string containing at most
+# 15 characters. %1$S is the search provider to use. %2$S is the string to
+# search for.
+openSearch.label=Chwilio %1$S am "%2$S"
+
+# LOCALIZATION NOTE (openSearch.label.truncated): The label used in the
+# autocomplete widget to refer to a search on the web for a short string
+# containing more than 15 characters. %1$S is the search provider to use. %2$S
+# is the string to search for, truncated to 15 characters.
+openSearch.label.truncated=Chwilio %1$S am "%2$S"
+
+# LOCALIZATION NOTE (aboutDialog.architecture.*):
+# The sixtyFourBit and thirtyTwoBit strings describe the architecture of the
+# current Thunderbird build: 32-bit or 64-bit. These strings are used in parentheses
+# after the Thunderbird version in the About dialog,
+# e.g.: "48.0.2 (32-bit)" or "51.0a1 (2016-09-05) (64-bit)".
+aboutDialog.architecture.sixtyFourBit = 64 did
+aboutDialog.architecture.thirtyTwoBit = 32 did
+
+errorConsoleTitle = Consol Gwall
+
+# LOCALIZATION NOTE (panel.back):
+# This is used by screen readers to label the "back" button in various browser
+# popup panels, including the sliding subviews of the appmenu.
+panel.back = Nôl
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EdAdvancedEdit.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EdAdvancedEdit.dtd
new file mode 100644
index 0000000000..3521a919ef
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EdAdvancedEdit.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY WindowTitle.label              "Golygydd Priodwedd Uwch">
+<!ENTITY AttName.label                  "Priodoledd: ">
+<!ENTITY AttValue.label                 "Gwerth: ">
+<!ENTITY PropertyName.label             "Priodwedd: ">
+<!ENTITY currentattributesfor.label     "Priodweddau cyfredol: ">
+<!ENTITY tree.attributeHeader.label     "Priodoledd">
+<!ENTITY tree.propertyHeader.label      "Priodwedd">
+<!ENTITY tree.valueHeader.label         "Gwerth">
+<!ENTITY tabHTML.label                  "Priodweddau HTML">
+<!ENTITY tabCSS.label                   "Arddull Mewn-lein">
+<!ENTITY tabJSE.label                   "Digwyddiadau JavaScript">
+
+<!ENTITY editAttribute.label    "Cliciwch ar eitem i olygu ei gwerth">
+<!ENTITY removeAttribute.label  "Tynnu">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EdColorPicker.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EdColorPicker.dtd
new file mode 100644
index 0000000000..29829fba85
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EdColorPicker.dtd
@@ -0,0 +1,22 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Lliw">
+<!ENTITY lastPickedColor.label "Lliw dewiswyd diwethaf">
+<!ENTITY lastPickedColor.accessKey "L">
+<!ENTITY chooseColor1.label "Dewis lliw:">
+<!ENTITY chooseColor2.label "Rhoi llinyn liw HTML">
+<!ENTITY chooseColor2.accessKey "H">
+<!ENTITY setColorExample.label "(e.e.: &quot;#0000ff&quot; neu &quot;blue&quot;):">
+<!ENTITY default.label "Rhagosodiad">
+<!ENTITY default.accessKey "R">
+<!ENTITY palette.label "Palet:">
+<!ENTITY standardPalette.label "Safonol">
+<!ENTITY webPalette.label "Pob lliw gwe">
+<!ENTITY background.label "Cefndir i:">
+<!ENTITY background.accessKey "e">
+<!ENTITY table.label "Tabl">
+<!ENTITY table.accessKey "T">
+<!ENTITY cell.label "Cell(oedd)">
+<!ENTITY cell.accessKey "C">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EdConvertToTable.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EdConvertToTable.dtd
new file mode 100644
index 0000000000..d818f65eba
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EdConvertToTable.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Trosi i Dabl">
+<!ENTITY instructions1.label   "Mae Cyfansoddwr yn creu rhes tabl newydd am bob paragraff yn y dewis.">
+<!ENTITY instructions2.label   "Dewiswch y nod fydd yn cael ei ddefnyddio i wahanu'r dewis yn golofnau:">
+<!ENTITY commaRadio.label      "Collnod">
+<!ENTITY spaceRadio.label      "Lle">
+<!ENTITY otherRadio.label      "Nod Arall:">
+<!ENTITY deleteCharCheck.label "Dileu nod gwahanu">
+<!ENTITY collapseSpaces.label  "Anwybyddu'r bylchau ychwanegol">
+<!ENTITY collapseSpaces.tooltip "Trosi'r bylchau cyfagos i un gwahanydd">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EdDialogOverlay.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EdDialogOverlay.dtd
new file mode 100644
index 0000000000..f924be47fc
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EdDialogOverlay.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY AdvancedEditButton.label "Golygu Uwch…">
+<!ENTITY AdvancedEditButton.accessKey "G">
+<!ENTITY AdvancedEditButton.tooltip "Ychwanegu neu newid Priodweddau HTML, priodweddau arddulliau a JavaScript">
+<!ENTITY chooseFileButton.label "Dewis Ffeil...">
+<!ENTITY chooseFileButton.accessKey "D">
+<!ENTITY chooseFileLinkButton.label "Dewis Ffeil...">
+<!ENTITY chooseFileLinkButton.accessKey "D">
+<!ENTITY makeUrlRelative.label "Mae'r URL yn berthynol i'r lleoliad tudalen">
+<!ENTITY makeUrlRelative.accessKey "U">
+<!ENTITY makeUrlRelative.tooltip "Newid rhwng URL absoliwt a pherthynol. Rhaid cadw'r dudalen yn gyntaf cyn gwneud hyn.">
+
+<!ENTITY LinkURLEditField2.label "Rhowch leoliad tudalen gwe, ffeil leol neu ddewis Angor a Enwyd neu Bennawd o feysydd y ddewislen cyd-destun:">
+<!ENTITY LinkURLEditField2.accessKey "w">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EdNamedAnchorProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EdNamedAnchorProperties.dtd
new file mode 100644
index 0000000000..510508d130
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EdNamedAnchorProperties.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodoleddau'r Angor a Enwyd">
+<!ENTITY anchorNameEditField.label "Enw'r Angor:">
+<!ENTITY anchorNameEditField.accessKey "E">
+<!ENTITY nameInput.tooltip "Rhowch enw unigryw ar gyfer yr angor (targed)">
+
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorColorProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorColorProperties.dtd
new file mode 100644
index 0000000000..2dffbd577a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorColorProperties.dtd
@@ -0,0 +1,29 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Lliwiau Tudalen a Chefndir">
+<!ENTITY pageColors.label "Lliwiau Tudalen">
+<!ENTITY defaultColorsRadio.label "Lliwiau Rhagosodedig y Darllenydd (Peidio gosod lliwiau ar y dudalen)">
+<!ENTITY defaultColorsRadio.accessKey "L">
+<!ENTITY defaultColorsRadio.tooltip "Defnyddio gosodiad lliw porwr y gwyliwr (darllenydd) yn unig">
+<!ENTITY customColorsRadio.label "Defnyddio lliwiau addasu:">
+<!ENTITY customColorsRadio.accessKey "D">
+<!ENTITY customColorsRadio.tooltip "Mae'r gosodiadau lliw hyn yn drech na gosodiadau'r porwr">
+
+<!ENTITY normalText.label "Testun arferol">
+<!ENTITY normalText.accessKey "T">
+<!ENTITY linkText.label "Testun dolen">
+<!ENTITY linkText.accessKey "d">
+<!ENTITY activeLinkText.label "Cyswllt testun gweithredol">
+<!ENTITY activeLinkText.accessKey "g">
+<!ENTITY visitedLinkText.label "Testun dolen wedi ymweld">
+<!ENTITY visitedLinkText.accessKey "o">
+<!ENTITY background.label "Cefndir:">
+<!ENTITY background.accessKey "e">
+<!ENTITY colon.character ":">
+<!ENTITY backgroundImage.label "Delweddau Cefndir:">
+<!ENTITY backgroundImage.accessKey "D">
+<!ENTITY backgroundImage.tooltip "Defnyddio ffeil delwedd fel cefndir ar gyfer eich tudalen">
+<!ENTITY backgroundImage.shortenedDataURI "URI data byrrach (bydd copi'n gosod yr URI llawn ar i'r clipfwrdd)">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorHLineProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorHLineProperties.dtd
new file mode 100644
index 0000000000..659a9ae24b
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorHLineProperties.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Priodweddau Llinell Lorweddol">
+
+<!ENTITY dimensionsBox.label "Dimensiynau">
+<!ENTITY heightEditField.label "Uchder:">
+<!ENTITY heightEditField.accessKey "U">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY pixelsPopup.value "picseli">
+<!ENTITY alignmentBox.label "Aliniad">
+<!ENTITY leftRadio.label "Chwith">
+<!ENTITY leftRadio.accessKey "C">
+<!ENTITY centerRadio.label "Canol">
+<!ENTITY centerRadio.accessKey "a">
+<!ENTITY rightRadio.label "De">
+<!ENTITY rightRadio.accessKey "D">
+
+<!ENTITY threeDShading.label "Gradd liwio 3-D">
+<!ENTITY threeDShading.accessKey "G">
+<!ENTITY saveSettings.label "Defnyddio fel Rhagosodiad">
+<!ENTITY saveSettings.accessKey "R">
+<!ENTITY saveSettings.tooltip "Cadw'r gosodiadau hyn i'w defnyddio wrth fewnosod llinellau llorweddol newydd">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorImageProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorImageProperties.dtd
new file mode 100644
index 0000000000..a01b54400d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorImageProperties.dtd
@@ -0,0 +1,81 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- These strings are for use specifically in the editor's image and form image dialogs. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Priodweddau Delwedd">
+
+<!ENTITY pixelsPopup.value "picseli">
+<!-- These are in the Location tab panel -->
+
+<!ENTITY locationEditField.label "Lleoliad delwedd:">
+<!ENTITY locationEditField.accessKey "L">
+<!ENTITY locationEditField.tooltip "Teipio enw neu leoliad ffeil y ddelwedd">
+<!ENTITY locationEditField.shortenedDataURI "URI data byrrach (bydd copi'n gosod yr URI llawn ar i'r clipfwrdd)">
+<!ENTITY title.label "Cyngor:">
+<!ENTITY title.accessKey "C">
+<!ENTITY title.tooltip "Y briodoledd 'teitl' sy'n cael ei ddangos fel cyngor">
+<!ENTITY altText.label "Testun eiledol:">
+<!ENTITY altText.accessKey "e">
+<!ENTITY altTextEditField.tooltip "Teipio testun i'w arddangos yn lle'r ddelwedd">
+<!ENTITY noAltText.label "Peidio defnyddio testun eiledol">
+<!ENTITY noAltText.accessKey "P">
+
+<!ENTITY previewBox.label "Rhagolwg Delwedd">
+
+<!-- These controls are in the Dimensions tab panel -->
+<!-- actualSize.label should be same as actualSizeRadio.label + ":" -->
+
+<!ENTITY actualSize.label "Maint Gwirioneddol:">
+<!ENTITY actualSizeRadio.label "Maint Gwirioneddol">
+<!ENTITY actualSizeRadio.accessKey "M">
+<!ENTITY actualSizeRadio.tooltip "Dychwelyd i faint gwirioneddol y ddelwedd">
+<!ENTITY customSizeRadio.label "Maint Cyfaddasu">
+<!ENTITY customSizeRadio.accessKey "a">
+<!ENTITY customSizeRadio.tooltip "Newid maint y ddelwedd fel y'i dangosir ar y dudalen">
+<!ENTITY heightEditField.label "Uchder:">
+<!ENTITY heightEditField.accessKey "U">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY constrainCheckbox.label "Cyfyngu">
+<!ENTITY constrainCheckbox.accessKey "f">
+<!ENTITY constrainCheckbox.tooltip "Cadw cyfradd agwedd y ddelwedd">
+<!-- These controls are in the Image Map box of the expanded area -->
+
+<!ENTITY imagemapBox.label "Map Delwedd">
+<!ENTITY removeImageMapButton.label "Tynnu">
+<!ENTITY removeImageMapButton.accessKey "T">
+<!-- These are the options for image alignment -->
+
+<!ENTITY alignment.label "Alinio Testun i'r Ddelwedd">
+<!ENTITY bottomPopup.value "Ar y gwaelod">
+<!ENTITY topPopup.value "Ar y brig">
+<!ENTITY centerPopup.value "Yn y canol">
+<!ENTITY wrapRightPopup.value "Amlapio i'r dde">
+<!ENTITY wrapLeftPopup.value "Amlapio i'r chwith">
+<!-- These controls are in the Spacing Box -->
+
+<!ENTITY spacingBox.label "Bylchu">
+<!ENTITY leftRightEditField.label "Chwith a De:">
+<!ENTITY leftRightEditField.accessKey "h">
+<!ENTITY topBottomEditField.label "Brig a Gwaelod:">
+<!ENTITY topBottomEditField.accessKey "B">
+<!ENTITY borderEditField.label "Ymyl Solet:">
+<!ENTITY borderEditField.accessKey "Y">
+<!-- These controls are in the Link Box -->
+
+<!ENTITY showImageLinkBorder.label "Dangos ymyl o amgylch delwedd gysylltiedig">
+<!ENTITY showImageLinkBorder.accessKey "D">
+<!ENTITY LinkAdvancedEditButton.label "Dolen Golygu Uwch…">
+<!ENTITY LinkAdvancedEditButton.accessKey "D">
+<!ENTITY LinkAdvancedEditButton.tooltip "Ychwanegu neu newid Priodweddau HTML, priodoleddau arddulliau a JavaScript">
+<!-- These tabs are currently used in the image input dialog -->
+
+<!ENTITY imageInputTab.label "Ffurflen">
+<!ENTITY imageLocationTab.label "Lleoliad">
+<!ENTITY imageDimensionsTab.label "Dimensiynau">
+<!ENTITY imageAppearanceTab.label "Gwedd">
+<!ENTITY imageLinkTab.label "Dolen">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertChars.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertChars.dtd
new file mode 100644
index 0000000000..494e858a23
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertChars.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Mewnosod Nod">
+<!ENTITY category.label "Categori">
+<!ENTITY letter.label "Llythyren:">
+<!ENTITY letter.accessKey "L">
+<!ENTITY character.label "Nod:">
+<!ENTITY character.accessKey "N">
+<!ENTITY accentUpper.label "Acen Priflythyren">
+<!ENTITY accentLower.label "Acen Llythyren fach">
+<!ENTITY otherUpper.label "Priflythyren Arall">
+<!ENTITY otherLower.label "Llythyren Fach Arall">
+<!ENTITY commonSymbols.label "Symbolau Cyffredin">
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY closeButton.label "Cau">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertMath.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertMath.dtd
new file mode 100644
index 0000000000..c3533186a1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertMath.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod Mathemateg">
+
+<!ENTITY sourceEditField.label "Rhosi'r cod ffynhonnell LaTeX:">
+
+<!ENTITY options.label "Dewisiadau">
+<!ENTITY optionInline.label "Modd mewnlin">
+<!ENTITY optionInline.accesskey "m">
+<!ENTITY optionDisplay.label "Modd dangos">
+<!ENTITY optionDisplay.accesskey "d">
+<!ENTITY optionLTR.label "Cyfeiriad chwith i'r dde">
+<!ENTITY optionLTR.accesskey "c">
+<!ENTITY optionRTL.label "Cyfeiriad de i'r chwith">
+<!ENTITY optionRTL.accesskey "d">
+
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY insertButton.accesskey "M">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertSource.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertSource.dtd
new file mode 100644
index 0000000000..09877577a5
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertSource.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod HTML">
+<!ENTITY sourceEditField.label "Gosod tagiau HTML a thestun:">
+<!ENTITY example.label "Enghraifft: ">
+<!-- LOCALIZATION NOTE (exampleOpenTag.label): DONT_TRANSLATE: they are text for HTML tagnames: "<i>" and "</i>" -->
+<!ENTITY exampleOpenTag.label "&lt;i&gt;">
+<!-- LOCALIZATION NOTE (exampleCloseTag.label): DONT_TRANSLATE: they are text for HTML tagnames: "<i>" and "</i>" -->
+<!ENTITY exampleCloseTag.label "&lt;/i&gt;">
+<!ENTITY exampleText.label "Helo Pawb!">
+<!ENTITY insertButton.label "Mewnosod">
+<!ENTITY insertButton.accesskey "M">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTOC.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTOC.dtd
new file mode 100644
index 0000000000..e30f42dfb2
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTOC.dtd
@@ -0,0 +1,16 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY Window.title        "Tabl Cynnwys">
+<!ENTITY buildToc.label      "Creu'r tabl cynnwys o:">
+<!ENTITY tag.label           "Tag:">
+<!ENTITY class.label         "Dosbarth:">
+<!ENTITY header1.label       "Lefel 1">
+<!ENTITY header2.label       "Lefel 2">
+<!ENTITY header3.label       "Lefel 3">
+<!ENTITY header4.label       "Lefel 4">
+<!ENTITY header5.label       "Lefel 5">
+<!ENTITY header6.label       "Lefel 6">
+<!ENTITY makeReadOnly.label  "Gwneud y tabl cynnwys yn darllen yn unig">
+<!ENTITY orderedList.label   "Rhifo pob cofnod yn y tabl cynnwys">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTable.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTable.dtd
new file mode 100644
index 0000000000..9a6acaa5f3
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorInsertTable.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Mewnosod Tabl">
+
+<!ENTITY size.label "Maint">
+<!ENTITY numRowsEditField.label "Rhesi:">
+<!ENTITY numRowsEditField.accessKey "R">
+<!ENTITY numColumnsEditField.label "Colofnau:">
+<!ENTITY numColumnsEditField.accessKey "C">
+<!ENTITY widthEditField.label "Lled:">
+<!ENTITY widthEditField.accessKey "L">
+<!ENTITY borderEditField.label "Ymyl:">
+<!ENTITY borderEditField.accessKey "Y">
+<!ENTITY borderEditField.tooltip "Teipio rhif ar gyfer ymyl y tabl, neu deipio sero (0) am ddim ymyl">
+<!ENTITY pixels.label "picseli">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorLinkProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorLinkProperties.dtd
new file mode 100644
index 0000000000..8f775351aa
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorLinkProperties.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY windowTitle.label "Priodweddau Dolen">
+<!ENTITY LinkURLBox.label "Lleoliad Dolen">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorListProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorListProperties.dtd
new file mode 100644
index 0000000000..15216ed8a2
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorListProperties.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+
+<!ENTITY windowTitle.label "Rhestri Priodweddau">
+
+<!ENTITY ListType.label "Math Rhestr">
+<!ENTITY bulletStyle.label "Arddull Bwled:">
+<!ENTITY startingNumber.label "Cychwyn yn:">
+<!ENTITY startingNumber.accessKey "C">
+<!ENTITY none.value "Dim">
+<!ENTITY bulletList.value "Rhestr Bwled (Heb ei rhifo)">
+<!ENTITY numberList.value "Rhestr wedi'i Rhifo">
+<!ENTITY definitionList.value "Rhestr Ddiffinio">
+<!ENTITY changeEntireListRadio.label "Newid y rhestr i gyd">
+<!ENTITY changeEntireListRadio.accessKey "N">
+<!ENTITY changeSelectedRadio.label "Newid rhai eitemau yn unig">
+<!ENTITY changeSelectedRadio.accessKey "r">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorPersonalDictionary.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorPersonalDictionary.dtd
new file mode 100644
index 0000000000..d14a116c40
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorPersonalDictionary.dtd
@@ -0,0 +1,18 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Geiriadur Personol">
+
+<!ENTITY wordEditField.label "Gair newydd:">
+<!ENTITY wordEditField.accessKey "n">
+<!ENTITY AddButton.label "Ychwanegu">
+<!ENTITY AddButton.accessKey "Y">
+<!ENTITY DictionaryList.label "Geiriau yn y geiriadur:">
+<!ENTITY DictionaryList.accessKey "G">
+<!ENTITY RemoveButton.label "Tynnu">
+<!ENTITY RemoveButton.accessKey "y">
+
+<!ENTITY CloseButton.label "Cau">
+<!ENTITY CloseButton.accessKey "u">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorReplace.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorReplace.dtd
new file mode 100644
index 0000000000..af0ee89438
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorReplace.dtd
@@ -0,0 +1,29 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- extracted from EdReplace.xul -->
+
+
+<!-- extracted from EdReplace.xhtml -->
+
+<!ENTITY replaceDialog.title "Canfod a Newid">
+<!ENTITY findField.label "Canfod testun:">
+<!ENTITY findField.accesskey "C">
+<!ENTITY replaceField.label "Newid gyda:">
+<!ENTITY replaceField.accesskey "N">
+<!ENTITY caseSensitiveCheckbox.label "Cydweddu maint">
+<!ENTITY caseSensitiveCheckbox.accesskey "C">
+<!ENTITY wrapCheckbox.label "Amlapio">
+<!ENTITY wrapCheckbox.accesskey "A">
+<!ENTITY backwardsCheckbox.label "Chwilio nôl">
+<!ENTITY backwardsCheckbox.accesskey "h">
+<!ENTITY findNextButton.label "Canfod nesaf">
+<!ENTITY findNextButton.accesskey "n">
+<!ENTITY replaceButton.label "Newid">
+<!ENTITY replaceButton.accesskey "N">
+<!ENTITY replaceAndFindButton.label "Newid a Chanfod">
+<!ENTITY replaceAndFindButton.accesskey "N">
+<!ENTITY replaceAllButton.label "Newid Popeth">
+<!ENTITY replaceAllButton.accesskey "N">
+<!ENTITY closeButton.label "Cau">
+<!ENTITY closeButton.accesskey "C">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorSpellCheck.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorSpellCheck.dtd
new file mode 100644
index 0000000000..e33f37022f
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorSpellCheck.dtd
@@ -0,0 +1,38 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Window title -->
+
+<!ENTITY windowTitle.label "Gwirio Sillafu">
+
+<!ENTITY misspelledWord.label "Gair wedi'i gamsillafu:">
+<!ENTITY wordEditField.label "Newid gyda:">
+<!ENTITY wordEditField.accessKey "N">
+<!ENTITY checkwordButton.label "Gwirio Gair">
+<!ENTITY checkwordButton.accessKey "G">
+<!ENTITY suggestions.label "Awgrymiadau:">
+<!ENTITY suggestions.accessKey "A">
+<!ENTITY ignoreButton.label "Anwybyddu">
+<!ENTITY ignoreButton.accessKey "A">
+<!ENTITY ignoreAllButton.label "Anwybyddu Popeth">
+<!ENTITY ignoreAllButton.accessKey "P">
+<!ENTITY replaceButton.label "Amnewid">
+<!ENTITY replaceButton.accessKey "m">
+<!ENTITY replaceAllButton.label "Newid y Cyfan">
+<!ENTITY replaceAllButton.accessKey "y">
+<!ENTITY stopButton.label "Atal">
+<!ENTITY stopButton.accessKey "A">
+<!ENTITY userDictionary.label "Geiriadur Personol:">
+<!ENTITY moreDictionaries.label "Llwytho rhagor o eiriaduron i lawr…">
+<!ENTITY addToUserDictionaryButton.label "Ychwanegu Gair">
+<!ENTITY addToUserDictionaryButton.accessKey "G">
+<!ENTITY editUserDictionaryButton.label "Golygu…">
+<!ENTITY editUserDictionaryButton.accessKey "G">
+<!ENTITY recheckButton2.label "Ailwirio'r Testun">
+<!ENTITY recheckButton2.accessKey "T">
+<!ENTITY closeButton.label "Cau">
+<!ENTITY closeButton.accessKey "u">
+<!ENTITY sendButton.label "Anfon">
+<!ENTITY sendButton.accessKey "A">
+<!ENTITY languagePopup.label "Iaith:">
+<!ENTITY languagePopup.accessKey "I">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/EditorTableProperties.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/EditorTableProperties.dtd
new file mode 100644
index 0000000000..456758cfa6
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/EditorTableProperties.dtd
@@ -0,0 +1,75 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY tableWindow.title                "Priodoleddau Tabl">
+<!ENTITY applyButton.label                "Gosod">
+<!ENTITY applyButton.accesskey            "G">
+<!ENTITY closeButton.label                "Cau">
+<!ENTITY tableTab.label                   "Tabl">
+<!ENTITY cellTab.label                    "Celloedd">
+<!ENTITY tableRows.label                  "Rhesi:">
+<!ENTITY tableRows.accessKey              "R">
+<!ENTITY tableColumns.label               "Colofnau:">
+<!ENTITY tableColumns.accessKey           "C">
+<!ENTITY tableHeight.label                "Uchder:">
+<!ENTITY tableHeight.accessKey            "U">
+<!ENTITY tableWidth.label                 "Lled:">
+<!ENTITY tableWidth.accessKey             "L">
+<!ENTITY tableBorderSpacing.label         "Ymyl a Bylchiad">
+<!ENTITY tableBorderWidth.label           "Ymyl:">
+<!ENTITY tableBorderWidth.accessKey       "Y">
+<!ENTITY tableSpacing.label               "Bylchu:">
+<!ENTITY tableSpacing.accessKey           "B">
+<!ENTITY tablePadding.label               "Padin:">
+<!ENTITY tablePadding.accessKey           "P">
+<!ENTITY tablePxBetwCells.label           "picseli rhwng celloedd">
+<!ENTITY tablePxBetwBrdrCellContent.label "picseli rhwng border celloedd a'r cynnwys">
+<!ENTITY tableAlignment.label             "Aliniad y Tabl:">
+<!ENTITY tableAlignment.accessKey         "T">
+<!ENTITY tableCaption.label               "Pennawd:">
+<!ENTITY tableCaption.accessKey           "e">
+<!ENTITY tableCaptionAbove.label          "Uwchlaw'r Tabl">
+<!ENTITY tableCaptionBelow.label          "Islaw'r Tabl">
+<!ENTITY tableCaptionLeft.label           "Chwith y Tabl">
+<!ENTITY tableCaptionRight.label          "De'r tabl">
+<!ENTITY tableCaptionNone.label           "Dim">
+<!ENTITY tableInheritColor.label           "(Gadael i liw'r dudalen ddangos drwodd)">
+
+<!ENTITY cellSelection.label              "Dewis">
+<!ENTITY cellSelectCell.label             "Cell">
+<!ENTITY cellSelectRow.label              "Rhes">
+<!ENTITY cellSelectColumn.label           "Colofn">
+<!ENTITY cellSelectNext.label             "Nesaf">
+<!ENTITY cellSelectNext.accessKey         "N">
+<!ENTITY cellSelectPrevious.label         "Blaenorol">
+<!ENTITY cellSelectPrevious.accessKey     "B">
+<!ENTITY applyBeforeChange.label          "Bydd y newidiadau cyfredol yn cael eu gosod chyn newid y dewis.">
+<!ENTITY cellContentAlignment.label       "Aliniad Cynnwys">
+<!ENTITY cellHorizontal.label             "Llorweddol:">
+<!ENTITY cellHorizontal.accessKey         "L">
+<!ENTITY cellVertical.label               "Fertigol:">
+<!ENTITY cellVertical.accessKey           "F">
+<!ENTITY cellStyle.label                  "Arddull Cell:">
+<!ENTITY cellStyle.accessKey              "A">
+<!ENTITY cellNormal.label                 "Arferol">
+<!ENTITY cellHeader.label                 "Pennyn">
+<!ENTITY cellTextWrap.label               "Amlapio Testun:">
+<!ENTITY cellTextWrap.accessKey           "A">
+<!ENTITY cellWrap.label                   "Amlapio">
+<!ENTITY cellNoWrap.label                 "Peidio amlapio">
+<!ENTITY cellAlignTop.label               "Brig">
+<!ENTITY cellAlignMiddle.label            "Canol">
+<!ENTITY cellAlignBottom.label            "Gwaelod">
+<!ENTITY cellAlignJustify.label           "Unioni">
+<!ENTITY cellInheritColor.label           "(Gadael lliw'r tabl ddangos trwodd)">
+<!ENTITY cellUseCheckboxHelp.label        "Defnyddio blychau ticio i bennu pa briodweddau sy'n cael eu cymhwyso i bob un o'r celloedd">
+<!-- Used in both Table and Cell panels  -->
+
+<!ENTITY size.label                       "Maint">
+<!ENTITY pixels.label                     "picseli">
+<!ENTITY backgroundColor.label            "Lliw Cefndir:">
+<!ENTITY backgroundColor.accessKey        "L">
+<!ENTITY AlignLeft.label                  "Chwith">
+<!ENTITY AlignCenter.label                "Canol">
+<!ENTITY AlignRight.label                 "De">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.dtd
new file mode 100644
index 0000000000..33175de435
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!--LOCALIZATION NOTE askSendFormat.dtd UI for dialog that asks the user, which format to use for sending a message -->
+
+<!ENTITY windowTitle.label "Cwestiwn E-bost HTML">
+
+<!ENTITY recipient.label "Mae rhai o'r derbynwyr heb eu rhestri eu bod yn gallu derbyn post HTML.">
+
+<!ENTITY question.label "Hoffech chi drosi'r neges i destun plaen ne ei anfon mewn HTML beth bynnag?">
+
+<!ENTITY plainTextAndHtml.label "Anfon mewn Testun Plaen a HTML">
+<!ENTITY plainTextAndHtml.accesskey "A">
+<!ENTITY plainTextOnly.label "Anfon mewn Testun Plaen yn Unig">
+<!ENTITY plainTextOnly.accesskey "T">
+<!ENTITY htmlOnly.label "Anfon mewn HTML yn Unig">
+<!ENTITY htmlOnly.accesskey "H">
+
+<!ENTITY send.label "Anfon">
+<!ENTITY send.accesskey "A">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.properties b/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.properties
new file mode 100644
index 0000000000..e7208574ae
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/askSendFormat.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+convertibleYes=Mae modd trosi eich neges i destun plaen heb golli unrhyw wybodaeth.
+convertibleAltering=Mae modd trosi eich neges i destun plaen heb golli gwybodaeth bwysig. Fodd bynnag, gall y fersiwn testun plaen edrych yn wahanol i'r hyn oedd yn y cyfansoddwr.
+convertibleNo=Er hynny, rydych wedi defnyddio fformatio (e.e lliwiau) na fydd yn cael ei drosi i destun plaen.
+recommended=(argymellir)
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/composeMsgs.properties b/l10n-cy/mail/chrome/messenger/messengercompose/composeMsgs.properties
new file mode 100644
index 0000000000..b44173f764
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/composeMsgs.properties
@@ -0,0 +1,493 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the compose back end
+#
+## LOCALIZATION NOTE (unableToOpenFile, unableToOpenTmpFile):
+## %S will be replaced with the name of file that could not be opened
+unableToOpenFile=Methu agor ffeil %S.
+unableToOpenTmpFile=Methu agor y ffeil dros dro %S. Gwiriwch eich gosodiadau 'Cyfeiriadur Dros dro'.
+unableToSaveTemplate=Methu cadw eich neges fel templed.
+unableToSaveDraft=Methu cadw eich negeseuon ar ffurf drafft.
+couldntOpenFccFolder=Methu agor ffolder Anfonwyd. Gwiriwch fod gosodiadau'ch cyfrif e-bost yn gywir.
+noSender=Heb bennu anfonwr. Ychwanegwch eich cyfeiriad e-bost yn ngosodiadau'r cyfrif.
+noRecipients=Heb enwi derbynwyr. Rhowch dderbynnydd neu grŵp newyddion yn y maes cyfeirio.
+errorWritingFile=Gwall wrth ysgrifennu ffeil dros dro.
+
+## LOCALIZATION NOTE (errorSendingFromCommand): argument %s is the Outgoing server (SMTP) response
+errorSendingFromCommand=Cafwyd gwall wrth anfon e-bost. Ymateb y gweinydd oedd: %s. Gwiriwch fod eich cyfeiriad e-bost yn gywir yn eich dewisiadau E-bost a cheisiwch eto.
+
+## LOCALIZATION NOTE (errorSendingDataCommand): argument %s is the Outgoing server (SMTP) response
+errorSendingDataCommand=Digwyddodd gwall (SMTP) wrth anfon e-bost. Ymateb y gweinydd oedd:  %s.
+
+## LOCALIZATION NOTE (errorSendingMessage): argument %s is the Outgoing server (SMTP) response
+errorSendingMessage=Digwyddodd gwall wrth anfon e-bost. Ymateb y gweinydd oedd:   %s. Gwiriwch y neges a cheisiwch eto.
+postFailed=Nid oedd modd cofnodi'r neges am i'r cyswllt a'r gweinydd e-bost fethu. Efallai nad yw'r gweinydd ar gael neu mae'n gwrthod cysylltiadau. Gwiriwch eich gosodiadau gwasanaethau e-bost a cheisiwch eto, neu cysylltwch â'ch gweinyddwr rhwydwaith.
+errorQueuedDeliveryFailed=Digwyddodd gwall wrth anfon negeseuon heb eu hanfon.
+sendFailed=Methwyd anfon neges.
+
+## LOCALIZATION NOTE (sendFailedUnexpected): argument %X is a hex error code value
+sendFailedUnexpected=Wedi methu oherwydd gwall annisgwyl %X. Nid oes disgrifiad ar gael.
+
+## LOCALIZATION NOTE (smtpSecurityIssue): argument %S is the Outgoing server (SMTP) response
+smtpSecurityIssue=Rhaid cywiro'r ffurfweddiad sy'n gysylltiedig â %S.
+
+## LOCALIZATION NOTE (smtpServerError): argument %s is the Outgoing server (SMTP) response
+smtpServerError=Digwyddodd gwall wrth anfon e-bost: Gwall gweinydd Anfon (SMTP). Ymateb y gweinydd oedd:  %s.
+unableToSendLater=Ymddiheuriadau, nid oedd modd cadw eich neges i'w hanfon yn hwyrach.
+
+## LOCALIZATION NOTE (communicationsError): argument %d is the error code
+communicationsError=Digwyddodd gwall cyfathrebu: %d.  Ceisiwch eto.
+dontShowAlert=THIS IS JUST A PLACEHOLDER.  YOU SHOULD NEVER SEE THIS STRING.
+
+couldNotGetUsersMailAddress2=Digwyddodd gwall wrth anfon e-bost: roedd cyfeiriad anfon yr e-bost yn annilys. Gwiriwch fod y cyfeiriad e-bost yn gywir a cheisiwch eto.
+couldNotGetSendersIdentity=Digwyddodd gwall wrth anfon e-bost: roedd hunaniaeth yr anfonwr yn annilys. Gwiriwch ffurfweddiad eich hunaniaeth a cheisiwch eto.
+
+mimeMpartAttachmentError=Gwall atodi.
+failedCopyOperation=Anfonwyd y neges yn llwyddiannus, ond nid oedd modd ei chopïo i'ch ffolder Anfon.
+nntpNoCrossPosting=Dim ond un neges mae modd anfon i un gweinydd newyddion ar y tro.
+msgCancelling=Diddymu…
+sendFailedButNntpOk=Mae eich neges wedi ei chofnodi at y grŵp newyddion ond nid yw wedi'i hanfon at dderbynnydd arall.
+errorReadingFile=Gwall darllen ffeil.
+followupToSenderMessage=Mae awdur y neges yn gofyn bod ymateb yn cael ei yrru at yr awdur yn unig. Os hoffech chi ymateb i'r grŵp newyddion, ychwanegwch res arall i'r maes cyfeiriad, dewis Grŵp Newyddion o'r rhestr derbynwyr a rhoi enw'r grŵp newyddion.
+
+## LOCALIZATION NOTE (errorAttachingFile): argument %S is the file name/URI of the object to be attached
+errorAttachingFile=Ddigwyddodd gwall wrth atodi %S. Gwiriwch fod gennych fynediad i'r ffeil.
+
+## LOCALIZATION NOTE (incorrectSmtpGreeting): argument %s is the Outgoing server (SMTP) greeting
+incorrectSmtpGreeting=Gwall wrth anfon e-bost: Anfonodd y gweinydd e-bost gyfarchiad anghywir:  %s.
+
+## LOCALIZATION NOTE (errorSendingRcptCommand): argument %1$S is the Outgoing server (SMTP) response, argument %2$S is the intended message recipient.
+errorSendingRcptCommand=Digwyddodd gwall wrth anfon e-bost. Ymateb y gweinydd e-bost oedd:  \n%1$S.\n Gwiriwch fod y derbynnydd neges "%2$S" yn gywir a cheisiwch eto.
+
+## LOCALIZATION NOTE (startTlsFailed): argument %S is the Outgoing server (SMTP)
+startTlsFailed=Gwall wrth anfon e-bost: Methu sefydlu cysylltiad diogel gyda gweinydd Anfon (SMTP) %S drwy STARTTLS am nad yw'n hysbysu'r nodwedd hwnnw. Diffoddwch STARTTLS ar gyfer y gweinydd hwnnw neu cysylltwch â'ch darparwr gwasanaeth.
+
+## LOCALIZATION NOTE (smtpPasswordUndefined): argument %S is the Outgoing server (SMTP) account
+smtpPasswordUndefined=Digwyddodd gwall wrth anfon negeseuon: Methu derbyn cyfrinair %S. Heb anfon y neges.
+
+## LOCALIZATION NOTE (smtpSendNotAllowed): argument %s is the Outgoing server (SMTP) response
+smtpSendNotAllowed=Digwyddodd gwall wrth anfon e-bost. Ymateb y gweinydd e-bost yw:\n %s.\nDylech sicrhau eich bod yn defnyddio'r hunaniaeth gywir i'w hanfon a bod y dull dilysu a ddefnyddir yn gywir. Gwiriwch eich bod yn gallu anfon eich tystysgrifau cyfredol o'r rhwydwaith presennol drwy'r gweinydd SMTP hwn.
+
+## LOCALIZATION NOTE (smtpTempSizeExceeded): argument %s is the Outgoing server (SMTP) response
+smtpTempSizeExceeded=Mae maint y neges rydych yn ceisio ei anfon yn fwy nag uchafswm dros dro'r gweinydd. Nid yw'r neges wedi'i hanfon; ceisiwch leihau maint y neges neu aros peth amser a cheisio eto. Ymateb y gweinydd:  %s.
+
+## LOCALIZATION NOTE (smtpClientid): argument %s is the Outgoing server (SMTP) response
+smtpClientid=Mae'r gweinydd allan (SMTP) wedi canfod gwall yn y gorchymyn CLIENTID. Nid yw'r neges wedi ei hanjfon. Ymateb y gweinydd yw: %s
+
+## LOCALIZATION NOTE (smtpClientidPermission): argument %s is the Outgoing server (SMTP) response
+smtpClientidPermission=Mae ymateb y gweinydd allan (SMTP) i'r gorchymyn CLIENTID yn awgrymu nad yw eich dyfais yn cael anfon e-byst. Ymateb y gweinydd yw: %s
+
+## LOCALIZATION NOTE (smtpPermSizeExceeded1): argument %d is the Outgoing server (SMTP) size limit
+smtpPermSizeExceeded1=Mae maint y neges rydych yn ceisio ei hanfon yn fwy nag uchafswm eang dros dro'r gweinydd (%d beit). Nid yw'r neges wedi'i hanfon; ceisiwch leihau maint y neges neu aros peth amser a cheisio eto.
+
+## LOCALIZATION NOTE (smtpPermSizeExceeded2): argument %s is the Outgoing server (SMTP) response
+smtpPermSizeExceeded2=Mae maint y neges rydych yn ceisio ei hanfon yn fwy nag uchafswm eang dros dro'r gweinydd. Nid yw'r neges wedi'i hanfon; ceisiwch leihau maint y neges neu aros peth amser a cheisio eto. Ymateb y gweinydd:  %s.
+
+## LOCALIZATION NOTE (smtpSendFailedUnknownServer): argument %S is the Outgoing server (SMTP)
+smtpSendFailedUnknownServer=Digwyddodd gwall wrth anfon e-bost: Mae'r gweinydd Anfon (SMTP) %S yn anhysbys. Efallai fod y gweinydd wedi'i ffurfweddu yn anghywir. Gwiriwch gosodiadau eich gweinydd (SMTP) yn gywir a cheisiwch eto.
+
+## LOCALIZATION NOTE (smtpSendRequestRefused): argument %S is the Outgoing server (SMTP)
+smtpSendRequestRefused=Nid oedd modd anfon y neges gan fod cysylltu â'r gweinydd Anfon (SMTP) %S wedi methu. Gall fod nad yw'r gweinydd ar gael neu'n gwrthod cysylltiadau SMTP. Gwiriwch fod gosodiadau eich gweinydd Allan (SMTP) yn gywir a cheisiwch eto.
+
+## LOCALIZATION NOTE (smtpSendInterrupted): argument %S is the Outgoing server (SMTP)
+smtpSendInterrupted=Nid oedd modd anfon y neges gan fod cysylltiad â'r gweinydd Anfon (SMTP) %S wedi ei golli yng nghanol trosglwyddiad. Ceisiwch eto.
+
+## LOCALIZATION NOTE (smtpSendTimeout): argument %S is the Outgoing server (SMTP)
+smtpSendTimeout=Nid oedd modd anfon y neges gan fod cysylltu â'r gweinydd Anfon (SMTP) %S wedi dod i ben. Ceisiwch eto.
+
+## LOCALIZATION NOTE (smtpSendFailedUnknownReason): argument %S is the Outgoing server (SMTP)
+smtpSendFailedUnknownReason=Nid oedd modd anfon y neges gan fod cysylltu â'r gweinydd Anfon (SMTP) %S am reswm anhysbys. Gwiriwch fod gosodiadau gweinydd Allan (SMTP) yn gywir a cheisiwch eto.
+
+# LOCALIZATION NOTE (smtpHintAuthEncryptToPlainNoSsl): %S is the server hostname
+smtpHintAuthEncryptToPlainNoSsl=Nid yw'r gweinydd Anfon (SMTP) %S i weld yn cynnal cyfrineiriau wedi eu hamgryptio. Os ydych newydd greu'r cyfrif, ceisiwch newydd y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gosodiadau gweinydd (SMTP)' i 'Cyfrinair, trosglwyddo anniogel'. Os oedd arfer gweithio ond nid yw nawr, gallwch fod yn agored i gael eich cyfrinair wedi ei ddwyn.
+
+# LOCALIZATION NOTE (smtpHintAuthEncryptToPlainSsl): %S is the server hostname
+smtpHintAuthEncryptToPlainSsl=Nid yw'r gweinydd Anfon (SMTP) %S i weld yn cynnal cyfrineiriau wedi eu hamgryptio. Os ydych newydd greu'r cyfrif, ceisiwch newydd y 'dull Dilysu' yn 'Gosodiadau Cyfrif | Gweinydd anfon (SMTP)' i 'Cyfrinair arferol'.
+
+# LOCALIZATION NOTE (smtpHintAuthPlainToEncrypt): %S is the server hostname
+smtpHintAuthPlainToEncrypt=Nid yw'r gweinydd Anfon (SMTP) %S yn caniatáu cyfrineiriau testun plaen. Ceisiwch newydd y 'dull Dilysu' yn 'Gosodiadau Cyfrif | Gweinydd anfon (SMTP)' i 'Cyfrinair amgryptiedig'.
+
+# LOCALIZATION NOTE (smtpAuthFailure): %S is the server hostname
+smtpAuthFailure=Methu dilysu gweinydd Anfon (SMTP) %S. Gwiriwch eich cyfrinair a dilysu eich 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gweinydd anfon' (SMTP)'.
+
+# LOCALIZATION NOTE (smtpAuthGssapi): %S is the server hostname
+smtpAuthGssapi=Nid yw'r tocyn Kerberos/GSSAPI ticket wedi'i dderbyn gan weinydd Anfon (SMTP) %S. Gwiriwch eich bod wedi eich mewngofnodi i gylch Kerberos/GSSAPI.
+
+# LOCALIZATION NOTE (smtpAuthMechNotSupported): %S is the server hostname
+smtpAuthMechNotSupported=Nid yw'r gweinydd Anfon (SMTP) %S yn cynnal y dull yma o ddilysu. Ceisiwch newid y 'Dull dilysu' yn 'Gosodiadau Cyfrif | Gweinydd Anfon (SMTP)'.
+
+# LOCALIZATION NOTE (errorIllegalLocalPart): %s is an email address with an illegal localpart
+errorIllegalLocalPart=Mae yn nodau nad ydynt yn ASCII yn rhan leol cyfeiriad derbynnydd %s. Nid yw hyn yn cael ei gynnal eto. Newidiwch y cyfeiriad a cheisiwch eto.
+
+# LOCALIZATION NOTE (errorIllegalLocalPart2): %s is an email address with an illegal localpart
+errorIllegalLocalPart2=Mae nodau nad ydynt yn ASCII yn rhan leol cyfeiriad y derbynnydd %s ac nid yw'ch gweinydd yn cefnogi SMTPUTF8. Newidiwch y cyfeiriad hwn a rhowch gynnig arall arni.
+
+## Strings used for the save message dialog shown when the user closes a message compose window
+saveDlogTitle=Cadw Neges
+
+## LOCALIZATION NOTE (saveDlogMessages3): Do not translate the words %1$S and \n.
+## %1$S is replaced by the folder name configured for saving drafts (typically the "Drafts" folder).
+## Translate "Write" to match the translation of item "windowTitleWrite" below.
+saveDlogMessages3=Cadw'r neges hon yn eich ffolder drafftiau (%1$S) a chau'r ffenestr Ysgrifennu?
+discardButtonLabel=&Dileu newidiadau
+
+## generics string
+defaultSubject=(dim pwnc)
+chooseFileToAttach=Atodi Ffeil(iau)
+genericFailureExplanation=Gwiriwch osodiadau eich cyfrif a rhowch gynnig arall arni.
+
+## LOCALIZATION NOTE (undisclosedRecipients): this string must use only US_ASCII characters
+undisclosedRecipients=derbynnydd cudd
+
+# LOCALIZATION NOTE (chooseFileToAttachViaCloud): %1$S is the cloud
+# provider to save the file to.
+chooseFileToAttachViaCloud=Atodi Ffeil(iau) drwy %1$S
+
+## Window titles
+# LOCALIZATION NOTE (windowTitleWrite):
+# %1$S is the message subject.
+# %2$S is the application name.
+# Example: Write: Re: Invitation - Thunderbird
+windowTitleWrite=Ysgrifennu: %1$S - %2$S
+# LOCALIZATION NOTE (windowTitlePrintPreview):
+# %1$S is the message subject.
+# %2$S is the application name.
+# Example: Print Preview: Re: Invitation - Thunderbird
+windowTitlePrintPreview=Rhagolwg Argraffu: %1$S - %2$S
+
+## From field
+msgIdentityPlaceholder=Rhowch gyfeiriad Oddi Wrth cyfaddas i'w ddefnyddio y lle %S
+customizeFromAddressTitle=Cyfaddasu Cyfeiriad Oddi Wrth
+customizeFromAddressWarning=Os yw eich darparwr e-byst yn ei gynnal, mae Cyfaddasu Cyfeiriad Oddi Wrth yn caniatáu i chi wneud mân newidiadau dros dro heb bod angen creu hunaniaeth newydd yn Ngosodiadau'r Cyfrif. Er enghraifft, os yw eich cyfeiriad Oddi wrth yn John Doe <john@example.com> efallai yr hoffech ei newid i John Doe <john+doe@example.com> neu John <john@example.com>.
+customizeFromAddressIgnore=Peidio fy hysbysu am hyn eto
+
+## Strings used by the empty subject dialog
+subjectEmptyTitle=Atgoffwr Pwnc
+subjectEmptyMessage=Nid oes gan eich neges bwnc.
+sendWithEmptySubjectButton=&Anfon Heb Bwnc
+cancelSendingButton=&Diddymu Anfon
+
+## Strings used by the dialog that informs about the lack of newsgroup support.
+noNewsgroupSupportTitle=Nid yw Grwpiau Newyddion yn Cael eu Cynnal
+recipientDlogMessage=Dim ond derbynwyr e-bost mae'r cyfrif yma yn ei gynnal. Bydd parhau yn anwybyddu grwpiau newyddion.
+
+## Strings used by the alert that tells the user that an e-mail address is invalid.
+addressInvalidTitle=Cyfeiriad Derbynnydd Annilys
+addressInvalid=Nid yw %1$S yn gyfeiriad e-bost dilys gan nad yw yn ffurf user@host. Rhaid cywiro hyn cyn anfon yr e-bost.
+
+## String used by the dialog that asks the user to attach a web page
+attachPageDlogTitle=Nodwch leoliad i'w atodi
+attachPageDlogMessage=Tudalen Gwe (URL):
+
+## String used for attachment pretty name, when the attachment is a message
+messageAttachmentSafeName=Neges wedi'i Hatodi
+
+## String used for attachment pretty name, when the attachment is a message part
+partAttachmentSafeName=Rhan o Neges wedi'i Hatodi
+
+# LOCALIZATION NOTE (attachmentBucketAttachFilesTooltip):
+# This tooltip should be same as attachFile.label in messengercompose.dtd,
+# but without ellipsis (…).
+attachmentBucketAttachFilesTooltip=Atodi Ffeil(iau)
+attachmentBucketClearSelectionTooltip=Clirio'r Dewis
+attachmentBucketHeaderShowTooltip=Dangos paen atodiad
+attachmentBucketHeaderMinimizeTooltip=Lleihau'r paen atodiad
+attachmentBucketHeaderRestoreTooltip=Adfer y paen atodiad
+
+## String used by the Initialization Error dialog
+initErrorDlogTitle=Ysgrifennu Neges
+initErrorDlgMessage=Digwyddodd gwall wrth greu ffenestr ysgrifennu neges. Ceisiwch eto.
+
+## String used if a file to attach does not exist when passed as
+## a command line argument
+errorFileAttachTitle=Atodi Ffeil
+
+## LOCALIZATION NOTE (errorFileAttachMessage): %1$S will be replaced by the non-existent file name.
+errorFileAttachMessage=Nid yw ffeil %1$S yn bodoli felly nid oedd modd ei hatodi i'r neges.
+
+## String used if a file to serve as message body does not exist or cannot be loaded when passed
+## as a command line argument
+errorFileMessageTitle=Ffeil Neges
+
+## LOCALIZATION NOTE (errorFileMessageMessage): %1$S will be replaced by the non-existent file name.
+errorFileMessageMessage=Nid yw ffeil %1$S yn bodoli ac nid oedd modd ei defnyddio fel corff neges.
+
+## LOCALIZATION NOTE (errorLoadFileMessageMessage): %1$S will be replaced by the name of the file that can't be loaded.
+errorLoadFileMessageMessage=Nid oedd modd llwytho %1$S fel corff neges.
+
+## Strings used by the Save as Draft/Template dialog
+SaveDialogTitle=Cadw Neges
+
+## LOCALIZATION NOTE (SaveDialogMsg): %1$S is the folder name, %2$S is the host name
+SaveDialogMsg=Mae eich neges wedi'i chadw i ffolder %1$S o dan %2$S.
+CheckMsg=Peidiwch dangos y blwch deialog hwn i mi eto.
+
+## Strings used by the prompt when Quitting while in progress
+quitComposeWindowTitle=Anfon Neges
+
+## LOCALIZATION NOTE (quitComposeWindowMessage2): don't translate \n
+quitComposeWindowMessage2=Mae %1$S wrthi'n anfon neges.\nHoffech chi aros tan fod y neges wedi ei hanfon cyn gadael neu gadael nawr?
+quitComposeWindowQuitButtonLabel2=&Gadael
+quitComposeWindowWaitButtonLabel2=&Aros
+quitComposeWindowSaveTitle=Cadw Neges
+
+## LOCALIZATION NOTE (quitComposeWindowSaveMessage): don't translate \n
+quitComposeWindowSaveMessage=Mae %1$S wrthi'n cadw neges.\nHoffech chi aros tan fod y neges wedi ei chadw cyn gadael neu gadael nawr?
+
+## Strings used by the prompt for Ctrl-Enter check before sending message
+sendMessageCheckWindowTitle=Anfon Neges
+sendMessageCheckLabel=Ydych chi'n siŵr eich bod yn barod i anfon y neges hon?
+sendMessageCheckSendButtonLabel=Anfon
+assemblingMessageDone=Cydosod neges...Wedi gorffen
+assemblingMessage=Cydosod neges…
+smtpDeliveringMail=Anfon e-bost…
+smtpMailSent=E-bost wedi'i anfon yn llwyddiannus
+assemblingMailInformation=Crynhoi gwybodaeth e-bost…
+
+## LOCALIZATION NOTE (gatheringAttachment): argument %S is the file name/URI of attachment
+gatheringAttachment=Atodi %S…
+creatingMailMessage=Creu neges e-bost…
+
+## LOCALIZATION NOTE (copyMessageStart): argument %S is the folder name
+copyMessageStart=Copïo neges i'r ffolder %S…
+copyMessageComplete=Copïo wedi gorffen.
+copyMessageFailed=Methodd copïo.
+filterMessageComplete=Mae'r hidl wedi ei gwblhau.
+filterMessageFailed=Methodd yr hidl.
+
+## LOCALIZATION NOTE (largeMessageSendWarning):
+## Do not translate %S. It is the size of the message in user-friendly notation.
+largeMessageSendWarning=Rhybudd! Rydych ar fin anfon neges o faint %S. Ydych chi'n siŵr eich bod eisiau gwneud hyn?
+sendingMessage=Anfon neges…
+sendMessageErrorTitle=Anfon Neges Gwall
+postingMessage=Cofnodi neges…
+sendLaterErrorTitle=Anfon Gwall Diweddarach
+saveDraftErrorTitle=Cadw Gwall Drafft
+saveTemplateErrorTitle=Cadw Gwall Templed
+
+## LOCALIZATION NOTE (failureOnObjectEmbeddingWhileSaving): argument %.200S is the file name/URI of object to be embedded
+failureOnObjectEmbeddingWhileSaving=Bu anhawster wrth gynnwys neges %.200S yn y neges. Hoffech chi barhau i gadw'r ffeil heb y neges?
+
+## LOCALIZATION NOTE (failureOnObjectEmbeddingWhileSending): argument %.200S is the file name/URI of object to be embedded
+failureOnObjectEmbeddingWhileSending=Bu anhawster wrth gynnwys y ffeil %.200S yn y neges. Hoffech chi barhau i anfon y neges heb y ffeil?
+returnToComposeWindowQuestion=Hoffech chi ddychwelyd i'r ffenestr ysgrifennu?
+
+## reply header in composeMsg
+## LOCALIZATION NOTE (mailnews.reply_header_authorwrotesingle): #1 is the author (name of the person replying to)
+mailnews.reply_header_authorwrotesingle=Ysgrifennodd #1:
+
+## LOCALIZATION NOTE (mailnews.reply_header_ondateauthorwrote): #1 is the author, #2 is the date, #3 is the time
+mailnews.reply_header_ondateauthorwrote=Ar #2 #3, ysgrifennodd #1:
+
+## LOCALIZATION NOTE (mailnews.reply_header_authorwroteondate): #1 is the author, #2 is the date, #3 is the time
+mailnews.reply_header_authorwroteondate=Ysgrifennodd #1 ar #2 #3:
+
+## reply header in composeMsg
+## user specified
+mailnews.reply_header_originalmessage=-------- Neges Wreiddiol --------
+
+## forwarded header in composeMsg
+## user specified
+mailnews.forward_header_originalmessage=-------- Neges Wreiddiol --------
+
+## Strings used by the rename attachment dialog
+renameAttachmentTitle=Ailenwi Atodiad
+renameAttachmentMessage=Enw newydd yr atodiad:
+
+## Attachment Reminder
+## LOCALIZATION NOTE (mail.compose.attachment_reminder_keywords): comma separated
+## words that should trigger an attachment reminder.
+mail.compose.attachment_reminder_keywords=.doc,.pdf,.xls,.ppt,.rtf,.pps,atodiad,attachment,atodi,attach,attached,attaching,amgaeëdig, enclosed,CV,llythyr,cover letter
+
+addAttachmentButton=Ychwanegu Atodiad…
+addAttachmentButton.accesskey=A
+remindLaterButton=Atgoffa Fi yn Ddiweddarach
+remindLaterButton.accesskey=D
+disableAttachmentReminderButton=Analluogwch atgoffwr atodiad ar gyfer y neges hon
+attachmentReminderTitle=Atgoffa am Atodiad
+attachmentReminderMsg=Ydych chi wedi anghofio atodi atodiad?
+
+# LOCALIZATION NOTE (attachmentReminderKeywordsMsgs): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# #1 number of keywords
+attachmentReminderKeywordsMsgs=Wedi canfod dim allweddeiriau atodiadau:;Wedi canfod #1 allweddair atodiad:;Wedi canfod #1 allweddair atodiad:;Wedi canfod #1 allweddair atodiad:;Wedi canfod #1 allweddair atodiad:;Wedi canfod #1 allweddair atodiad:
+attachmentReminderOptionsMsg=Mae modd ffurfweddi geiriau ar gyfer atodiadau yn eich dewisiadau
+attachmentReminderYesIForgot=O, do!
+attachmentReminderFalseAlarm=Na, Anfon Nawr
+
+# Strings used by the Filelink offer notification bar.
+learnMore.label=Dysgu Rhagor…
+learnMore.accesskey=D
+
+# LOCALIZATION NOTE (bigFileDescription): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# #1 number of big attached files
+bigFileDescription=Dim ffeiliau.;Mae'r ffeiliau hyn yn fawr iawn. Efallai y byddai'n well defnyddio Filelink.;Mae'r ffeiliau hyn yn fawr iawn. Efallai y byddai'n well defnyddio Filelink.;Mae'r ffeiliau hyn yn fawr iawn. Efallai y byddai'n well defnyddio Filelink.;Mae'r ffeiliau hyn yn fawr iawn. Efallai y byddai'n well defnyddio Filelink.;Mae'r ffeiliau hyn yn fawr iawn. Efallai y byddai'n well defnyddio Filelink.
+bigFileShare.label=Dolen
+bigFileShare.accesskey=D
+bigFileAttach.label=Anwybyddu
+bigFileAttach.accesskey=A
+bigFileChooseAccount.title=Dewis Cyfrif
+bigFileChooseAccount.text=Dewis cyfrif cwmwl i lwytho'r atodiad iddo
+bigFileHideNotification.title=Peidio Llwytho fy Ffeiliau i Fyny
+bigFileHideNotification.text=Ni fyddwch yn cael eich hysbysu os byddwch yn atodi rhagor o ffeiliau mawr i'r neges hon.
+bigFileHideNotification.check=Peidio fy hysbysu am hyn eto.
+
+# LOCALIZATION NOTE(cloudFileUploadingTooltip): Do not translate the string
+# %S. %S is the display name for the cloud account the attachment is being
+# uploaded to.
+cloudFileUploadingTooltip=Llwytho i fyny i %S…
+
+# LOCALIZATION NOTE(cloudFileUploadedTooltip): Do not translate the string
+# %S. %S is the display name for the cloud account the attachment was uploaded
+# to.
+cloudFileUploadedTooltip=Wedi'u llwytho i fyny i %S
+cloudFileUploadingNotification=Mae eich ffeil wedi'i chysylltu. Bydd yn ymddangos yng nghorff y neges ar ôl ei gwblhau.;Mae eich ffeiliau wedi'u cysylltu. Byddant yn ymddangos yng nghorff y neges ar ôl ei gwblhau.
+cloudFileUploadingCancel.label=Diddymu
+cloudFileUploadingCancel.accesskey=D
+cloudFilePrivacyNotification=Mae cysylltu wedi ei gwblhau. Sylwch y gall atodiadau sydd wedi eu cysylltu fod yn agored i bobl all weld neu ddyfalu'r dolenni.
+
+## LOCALIZATION NOTE(smtpEnterPasswordPrompt): Do not translate the
+## word %S. Place the word %S where the host name should appear.
+smtpEnterPasswordPrompt=Rhowch eich cyfrinair ar gyfer %S:
+
+## LOCALIZATION NOTE(smtpEnterPasswordPromptWithUsername): Do not translate the
+## words %1$S and %2$S. Place the word %1$S where the host name should appear,
+## and %2$S where the user name should appear.
+smtpEnterPasswordPromptWithUsername=Rhowch eich cyfrinair ar gyfer %2$S ar %1$S:
+## LOCALIZATION NOTE(smtpEnterPasswordPromptTitleWithHostname): Do not translate the
+## word %1$S. Place the word %1$S where the server host name should appear.
+smtpEnterPasswordPromptTitleWithHostname=Mae Angen Cyfrinair ar gyfer Gweinydd Allanol (SMTP) %1$S
+
+# LOCALIZATION NOTE (removeAttachmentMsgs): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+removeAttachmentMsgs=Dim Atodiadau;Tynnu Atodiad;Tynnu Atodiadau;Tynnu Atodiadau;Tynnu Atodiadau;Tynnu Atodiadau
+
+## LOCALIZATION NOTE(promptToSaveSentLocally2): Do not translate the strings %1$S, %2$S, %3$S and \n.
+## %2$S will be replaced with the account name. $1$S will be replaced by the folder name
+## configured to contain saved sent messages (typically the "Sent" folder).
+## %3$S will be replaced with the local folders account name (typically "Local Folders").
+## Translate "Write" to match the translation of item "windowTitleWrite" above.
+promptToSaveSentLocally2=Anfonwyd eich neges ond nid oes copi wedi ei gosod yn eich ffolder anfon (%1$S) oherwydd gwallau rhwydwaith neu fynediad i ffeil.\nGallwch geisio eto neu gadw'r neges yn lleol i %3$S/%1$S-%2$S.
+errorFilteringMsg=Mae eich neges wedi ei hanfon a'i chadw, ond bu gwall wrth redeg yr hidlau neges arni.
+errorCloudFileAuth.title=Gwall Dilysu
+
+## LOCALIZATION NOTE(promptToSaveDraftLocally2): Do not translate the strings %1$S, %2$S, %3$S and \n.
+## %2$S will be replaced with the account name. $1$S will be replaced by the folder name
+## configured to contain saved draft messages (typically the "Drafts" folder).
+## %3$S will be replaced with the local folders account name (typically "Local Folders").
+promptToSaveDraftLocally2=Nid yw eich neges ddrafft wedi ei chopïo i'ch ffolder drafft (%1$S) oherwydd gwallau rhwydwaith neu fynediad i ffeil.\nGallwch geisio eto neu gadw'r neges yn lleol i %3$S/%1$S-%2$S.
+buttonLabelRetry2=&Ceisio eto
+
+## LOCALIZATION NOTE(promptToSaveTemplateLocally2): Do not translate the strings %1$S, %2$S, %3$S and \n.
+## %2$S will be replaced with the account name. $1$S will be replaced by the folder name
+## configured to contain saved templates (typically the "Templates" folder).
+## %3$S will be replaced with the local folders account name (typically "Local Folders").
+promptToSaveTemplateLocally2=Nid yw eich templed wedi ei gopïo i'ch ffolder templedi (%1$S) oherwydd gwallau rhwydwaith neu fynediad i ffeil.\nGallwch geisio eto neu gadw'r neges yn lleol i %3$S/%1$S-%2$S.
+
+## LOCALIZATION NOTE(saveToLocalFoldersFailed): Message appears after normal
+## save fails (e.g., to Sent) and save to Local Folders also fails. This could
+## occur if network is down and filesystem problems are present such as disk
+## full, permission issues or hardware failure.
+saveToLocalFoldersFailed=Methu cadw eich neges i ffolderi lleol. Posib nad oes lle storio yn weddill.
+
+## LOCALIZATION NOTE(errorCloudFileAuth.message):
+## %1$S is the name of the online storage service against which the authentication failed.
+errorCloudFileAuth.message=Methu dilysu i %1$S.
+errorCloudFileUpload.title=Gwall Llwytho i Fyny
+
+## LOCALIZATION NOTE(errorCloudFileUpload.message):
+## %1$S is the name of the online storage service against which the uploading failed.
+## %2$S is the name of the file that failed to upload.
+errorCloudFileUpload.message=Methu llwytho %2$S i fyny i %1$S.
+errorCloudFileQuota.title=Gwall Cwota
+
+## LOCALIZATION NOTE(errorCloudFileQuota.message):
+## %1$S is the name of the online storage service being uploaded to.
+## %2$S is the name of the file that could not be uploaded due to exceeding the storage limit.
+errorCloudFileQuota.message=Bydd llwytho %2$S i fyny i %1$S yn croesi trothwy eich cwota.
+errorCloudFileNameLimit.title=Gwall Enw Ffeil
+
+## LOCALIZATION NOTE(errorCloudFileNameLimit.message):
+## %1$S is the name of the online storage service being uploaded to.
+## %2$S is the name of the file that could not be uploaded due to the excess file name length
+errorCloudFileNameLimit.message=Mae %2$S yn cynnwys mwy na 120 nod yn ei enw, sy'n fwy na uchafswm hyd enw ffeil ar gyfer %1$S. Ailenwch y ffeil i fod yn llai na 120 nod a llwythwch y ffeil i fyny eto.
+errorCloudFileLimit.title=Gwall Maint Ffeil
+
+## LOCALIZATION NOTE(errorCloudFileLimit.message):
+## %1$S is the name of the online storage service being uploaded to.
+## %2$S is the name of the file that could not be uploaded due to size restrictions.
+errorCloudFileLimit.message=Mae %2$S yn fwy na maint mwyaf %1$S.
+errorCloudFileOther.title=Gwall Anhysbys
+
+## LOCALIZATION NOTE(errorCloudFileOther.message):
+## %1$S is the name of the online storage service that cannot be communicated with.
+errorCloudFileOther.message=Digwyddodd gwall anhysbys wrth gyfathrebu gyda %1$S.
+errorCloudFileDeletion.title=Gwall Dileu
+
+## LOCALIZATION NOTE(errorCloudFileDeletion.message):
+## %1$S is the name of the online storage service that the file is to be deleted from.
+## %2$S is the name of the file that failed to be deleted.
+errorCloudFileDeletion.message=Nid oedd anhawster wrth ddileu %2$S o %1$S.
+errorCloudFileUpgrade.label=Diweddaru
+
+## LOCALIZATION NOTE(cloudAttachmentCountHeader): A line of text describing how
+## many uploaded files have been appended to this message.  Emphasis should be
+## on sharing as opposed to attaching. This item is used as a header to a list,
+## hence the colon.  This header is only displayed in HTML emails.
+## Using PluralForm (so don't replace the #1).
+cloudAttachmentCountHeader=Rwyf wedi cysylltu #1 ffeil i'r e-bost hwn:;Rwyf wedi cysylltu #1 ffeil i'r e-bost hwn:
+
+## LOCALIZATION NOTE(cloudAttachmentListFooter): %1$S is a link, whose text
+## contents are the brandFullName of this application.
+cloudAttachmentListFooter=Mae %1$S yn ei gwneud yn hawdd i rannu ffeiliau mawr drwy e-bost.
+
+## LOCALIZATION NOTE(cloudAttachmentListItem): A line of text describing a cloud
+## attachment to be inserted into the message body. Do not translate the words
+## %1$S, %2$S, %3$S, or %4$S. %1$S is the attachment name, %2$S is its size,
+## %3$S is the name of the cloud storage service, and %4$S is the link to the
+## attachment.
+cloudAttachmentListItem=* %1$S (%2$S) wedi ei westeio ar %3$S: %4$S
+
+## LOCALIZATION NOTE(stopShowingUploadingNotification): This string is used in the Filelink
+## upload notification bar to allow the user to dismiss the notification permanently.
+stopShowingUploadingNotification.accesskey=P
+stopShowingUploadingNotification.label=Peidio dangos hwn eto
+replaceButton.label=Amnewid…
+replaceButton.accesskey=a
+replaceButton.tooltip=Dangos y deialog Canfod ac Newid
+
+## LOCALIZATION NOTE(blockedAllowResource): %S is the URL to load.
+blockedAllowResource=Dadrwystro %S
+## LOCALIZATION NOTE (blockedContentMessage): Semi-colon list of plural forms.
+## See: https://developer.mozilla.org/en/docs/Localization_and_Plurals
+## %S will be replaced by brandShortName.
+## Files must be unblocked individually, therefore the plural form reads:
+## Unblocking a file (one of several) will include it (that one file) in your sent message.
+## In other words:
+## Unblocking one/several file(s) will include it/them in your message.
+blockedContentMessage=Nid yw %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd;Mae %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd.;Mae %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd.;Mae %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd.;Mae %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd.;Mae %S wedi rhwystro ffeiliau rhag llwytho i'r neges hon. Bydd dad-rwystro'r ffeil yn ei chynnwys yn eich neges a anfonwyd.
+
+blockedContentPrefLabel=Dewisiadau
+blockedContentPrefAccesskey=D
+
+blockedContentPrefLabelUnix=Dewisiadau
+blockedContentPrefAccesskeyUnix=e
+
+## Identity matching warning notification bar.
+## LOCALIZATION NOTE(identityWarning): %S will be replaced with the identity name.
+identityWarning=Methu canfod hunaniaeth unigryw sy'n cyd-fynd a'r cyfeiriad Oddi wrth. Bydd y neges yn cael ei hanfon gan ddefnyddio'r maes Oddi wrth cyfredol a'r gosodiadau o hunaniaeth %S.
+
+## Recipient pills fields.
+## LOCALIZATION NOTE(confirmRemoveRecipientRowTitle2): %S will be replaced with the field name.
+confirmRemoveRecipientRowTitle2=Tynnwch Gyfeiriadau %S
+## LOCALIZATION NOTE(confirmRemoveRecipientRowBody2): %S will be replaced with the field name.
+confirmRemoveRecipientRowBody2=Ydych chi'n siŵr eich bod am gael gwared ar gyfeiriadau %S?
+confirmRemoveRecipientRowButton=Tynnu
+
+## LOCALIZATION NOTE headersSpaceStyle is for aligning label of a newly create recipient row.
+## It should be larger than the largest Header label and identical to &headersSpace2.style;
+headersSpaceStyle=width: 8em
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/editor.properties b/l10n-cy/mail/chrome/messenger/messengercompose/editor.properties
new file mode 100644
index 0000000000..62a5d47d26
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/editor.properties
@@ -0,0 +1,208 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE FILE: embedded "\n" represent HTML breaks (<br>)
+# Don't translate embedded "\n".
+# Don't translate strings like this: %variable% 
+#  as they will be replaced using JavaScript
+#
+No=Na
+Save=Cadw
+More=Rhagor
+Less=Llai
+MoreProperties=Rhagor o Briodweddau
+FewerProperties=Llai o Briodweddau
+PropertiesAccessKey=P
+None=Dim
+none=dim
+OpenHTMLFile=Agor Ffeil HTML
+OpenTextFile=Agor Ffeil Testun
+SelectImageFile=Dewiswch Ffeil Delwedd
+SaveDocument=Cadw Tudalen
+SaveDocumentAs=Cadw Tudalen Fel
+SaveTextAs=Cadw Testun Fel
+EditMode=Modd Golygu
+Preview=Rhagolwg
+Publish=Cyhoeddi
+PublishPage=Cyhoeddi Tudalen
+DontPublish=Peidio Cyhoeddi
+SavePassword=Defnyddiwch y Rheolwr Cyfrinair i gadw'r cyfrinair
+CorrectSpelling=(sillafu cywir)
+NoSuggestedWords=(dim geiriau'n cael eu cynnig)
+NoMisspelledWord=Does dim geiriau wedi'u camsillafu
+CheckSpellingDone=Cwblhawyd gwirio'r sillafu.
+CheckSpelling=Gwirio Sillafu
+InputError=Gwall
+Alert=Rhybudd
+CantEditFramesetMsg=Nid yw'r golygydd yn gallu golygu fframsetiau HTML na thudalennau gyda fframiau mewnlin. Ar gyfer fframsetiau ceisiwch olygu'r dudalen ar gyfer pob ffrâm ar wahân. Am dudalennau gyda fframiau, cadwch gopi o'r dudalen a thynnu'r tag <iframe>.
+CantEditMimeTypeMsg=Does dim modd golygu'r math yma o dudalen.
+CantEditDocumentMsg=Does dim modd golygu'r dudalen am reswm anhysbys.
+BeforeClosing=cyn cau
+BeforePreview=cyn edrych arno yn y porwr
+BeforeValidate=cyn gwirio'r ddogfen
+# LOCALIZATION NOTE (SaveFilePrompt, PublishPrompt): Don't translate %title% and %reason% (this is the reason for asking user to close, such as "before closing")
+SaveFilePrompt=Cadw newidiadau i "%title%" %reason%?\u0020
+PublishPrompt=Cadw newidiadau i "%title%" %reason%?\u0020
+SaveFileFailed=Methwyd cadw'r ffeil!
+
+# Publishing error strings:
+# LOCALIZATION NOTE Don't translate %dir% or %file% in the Publishing error strings:
+FileNotFound=Heb ganfod %file%.
+SubdirDoesNotExist=Nid yw'r is-gyfeiriadur "%dir%" yn bodoli ar y safle hwn neu mae'r enw ffeil "%file%" yn cael ei ddefnyddio gan is-gyfeiriadur arall.
+FilenameIsSubdir=Mae'r enw ffeil "%file%" yn cael ei ddefnyddio eisoes gan is-gyfeiriadur arall.
+ServerNotAvailable=Nid yw'r gweinydd ar gael. Gwiriwch eich cysylltiad a cheisiwch eto yn ddiweddarach.
+Offline=Rydych all-lein. Cliciwch yr eicon wrth ymyl y gornel de gwaelod unrhyw ffenestr i fynd ar-lein.
+DiskFull=Does dim digon o le ar ddisg ar gael i gadw ffeil "%file%."
+NameTooLong=Mae'r enw ffeil neu is-gyfeiriadur yn rhy hir.
+AccessDenied=Does gennych ddim caniatâd i chi gyhoeddi i'r lleoliad hwn.
+UnknownPublishError=Digwyddodd gwall cyhoeddi anhysbys.
+PublishFailed=Methodd y cyhoeddi.
+PublishCompleted=Wedi cwblhau'r cyhoeddi.
+AllFilesPublished=Pob ffeil eu cyhoeddi
+# LOCALIZATION NOTE Don't translate %x% or %total%
+FailedFileMsg=Methodd %x% o %total% ffeil gael eu cyhoeddi.
+# End-Publishing error strings
+Prompt=Anogiad
+# LOCALIZATION NOTE (PromptFTPUsernamePassword): Don't translate %host% 
+PromptFTPUsernamePassword=Rhowch enw defnyddiwr a chyfrinair ar gyfer gweinydd FTP %host%
+RevertCaption=Dychwelyd i Cadwyd Diwethaf
+Revert=Dychwelyd
+SendPageReason=cyn anfon y dudalen
+Send=Anfon
+## LOCALIZATION NOTE (PublishProgressCaption, PublishToSite, AbandonChanges): Don't translate %title%
+PublishProgressCaption=Cyhoeddi: %title%
+PublishToSite=Cyhoeddi i Wefan: %title%
+AbandonChanges=Gadael newidiadau heb eu cadw i "%title%" ac ail-lwytho'r dudalen?
+DocumentTitle=Teitl y Dudalen
+NeedDocTitle=Rhoi teitl i'r dudalen gyfredol.
+DocTitleHelp=Mae hwn yn adnabod y dudalen yn nheitl y ffenestr a'r nodau tudalen.
+CancelPublishTitle=Diddymu'r cyhoeddi?
+## LOCALIZATION NOTE: "Continue" in this sentence must match the text for
+## the CancelPublishContinue key below
+CancelPublishMessage=Gall diddymu argraffu arwain at eich ffeil(iau)'n cael eu trosglwyddo'n wallus. Parhau neu Diddymu?
+CancelPublishContinue=Parhau
+MissingImageError=Rhoi neu ddewis ddelwedd gif, jpg, neu png.
+EmptyHREFError=Rhaid rhoi neu ddewis lleoliad i greu dolen newydd.
+LinkText=Cysylltu Testun
+LinkImage=Cysylltu Delwedd
+MixedSelection=[Dewis cymysg]
+Mixed=(cymysg)
+# LOCALIZATION NOTE (NotInstalled): %S is the name of the font
+NotInstalled=%S (heb ei osod)
+EnterLinkText=Rhoi testun i'w arddangos ar gyfer y ddolen:
+EnterLinkTextAccessKey=T
+EmptyLinkTextError=Rhowch ychydig o destun ar gyfer y ddolen.
+EditTextWarning=Bydd hwn yn cymryd lle'r cynnwys cyfredol.
+#LOCALIZATION NOTE (ValidateNumber):Don't translate: %n% %min% %max%
+ValidateRangeMsg=Mae'r rhif rydych wedi'i rhoi (%n%) tu allan i'r amrediad sy'n cael ei ganiatáu.
+ValidateNumberMsg=Rhowch rif rhwng %min% a %max%.
+MissingAnchorNameError=Rhowch enw i'r angor.
+#LOCALIZATION NOTE (DuplicateAnchorNameError): Don't translate %name%
+DuplicateAnchorNameError=Mae "%name%" yn bodoli eisoes ar y dudalen. Rhowch enw gwahanol.
+BulletStyle=Arddull Bwled
+SolidCircle=Cylch solet
+OpenCircle=Cylch agored
+SolidSquare=Sgwâr solet
+NumberStyle=Arddull Rhif
+Automatic=Awtomatig
+Style_1=1, 2, 3…
+Style_I=I, II, III…
+Style_i=i, ii, iii…
+Style_A=A, B, C…
+Style_a=a, b, c…
+Pixels=picseli
+Percent=y cant
+PercentOfCell=% o gell
+PercentOfWindow=% o ffenestr
+PercentOfTable=% o dabl
+#LOCALIZATION NOTE (untitledTitle): %S is the window #.  No plural handling needed.
+untitledTitle=dideitl-%S
+untitledDefaultFilename=dideitl
+ShowToolbar=Dangos Bar Offer
+HideToolbar=Cuddio'r Bar Offer
+ImapError=Methu llwytho'r ddelwedd\u0020
+ImapCheck=\nDewiswch leoliad (URL) newydd a cheisiwch eto.
+SaveToUseRelativeUrl=Dim ond ar dudalennau sydd wedi'u cadw mae modd defnyddio URL sy'n perthyn
+NoNamedAnchorsOrHeadings=(Nid oes angorau a enwyd na phenawdau ar y dudalen)
+TextColor=Lliw Testun
+HighlightColor=Lliw Amlygu
+PageColor=Lliw Cefndir Tudalen
+BlockColor=Rhwystro Cefndir Lliw
+TableColor=Lliw Cefndir Tabl
+CellColor=Lliw Cefndir Cell
+TableOrCellColor=Lliw Tabl neu Gell
+LinkColor=Lliw'r Testun Dolen
+ActiveLinkColor=Lliw Dolen Gweithredol
+VisitedLinkColor=Lliw Dolen Ymwelwyd
+NoColorError=Cliciwch ar liw neu roi llinyn lliw o HTML dilys
+Table=Tabl
+TableCell=Cell Tabl
+NestedTable=Tabl Nythwyd
+HLine=Llinell Llorweddol
+Link=Dolen
+Image=Delwedd
+ImageAndLink=Delwedd a Dolen
+NamedAnchor=Angor a Enwyd
+List=Rhestr
+ListItem=Rhestri'r eitem
+Form=Ffurflen
+InputTag=Maes Ffurflen
+InputImage=Delwedd Ffurflen
+TextArea=Ardal Testun
+Select=Rhestr Dewis
+Button=Botwm
+Label=Label
+FieldSet=Set Maes
+Tag=Tag
+MissingSiteNameError=Rhowch enw ar gyfer y wefan cyhoeddi.
+MissingPublishUrlError=Rhowch leoliad i gyhoeddi'r dudalen.
+MissingPublishFilename=Rhowch enw ffeil ar gyfer y dudalen gyfredol.
+#LOCALIZATION NOTE (DuplicateSiteNameError): Don't translate %name%
+DuplicateSiteNameError=Mae "%name%" yn bodoli eisoes. Rhowch enw safle gwahanol.
+AdvancedProperties=Priodweddau Uwch…
+AdvancedEditForCellMsg=Nid yw Golygu Uwch ar gael pan fydd celloedd niferus wedi'u dewis
+# LOCALIZATION NOTE (ObjectProperties):Don't translate "%obj%" it will be replaced with one of above object nouns
+ObjectProperties=Priodweddau %obj%…
+# LOCALIZATION NOTE This character must be in the above string and not confict with other accesskeys in Format menu
+ObjectPropertiesAccessKey=o
+# LOCALIZATION NOTE (JoinSelectedCells): This variable should contain the "tableJoinCells.accesskey" 
+# letter as defined in editorOverlay.dtd
+JoinSelectedCells=Uno'r Celloedd
+# LOCALIZATION NOTE (JoinCellToRight): This variable should contain the "tableJoinCells.accesskey" 
+# letter as defined in editorOverlay.dtd
+JoinCellToRight=Uno gyda'r Gell i'r Dde
+JoinCellAccesskey=j
+# LOCALIZATION NOTE (TableSelectKey): Ctrl key on a keyboard
+TableSelectKey=Ctrl+
+# LOCALIZATION NOTE (XulKeyMac): Command key on a Mac keyboard
+XulKeyMac=Cmd+
+# LOCALIZATION NOTE (Del): Del key on a keyboard
+Del=Del
+Delete=Dileu
+DeleteCells=Dileu Celloedd
+DeleteTableTitle=Dileu Rhesi neu Golofnau
+DeleteTableMsg=Bydd lleihau'r nifer o resi neu golofnau yn dileu celloedd tabl a'u cynnwys. Ydych chi wir eisiau gwneud hyn?
+Clear=Clirio
+#Mouse actions
+Click=Cliciwch
+Drag=Llusgo
+Unknown=Anhysbys
+#
+# LOCALIZATION NOTE "RemoveTextStylesAccesskey" is used for both
+#  menu items: "RemoveTextStyles" and "StopTextStyles"
+RemoveTextStylesAccesskey=x
+RemoveTextStyles=Tynnu Pob Arddull Testun
+StopTextStyles=Peidio Parhau gyda'r Arddulliau Testun
+#
+# LOCALIZATION NOTE "RemoveLinksAccesskey" is used for both
+#  menu items: "RemoveLinks" and "StopLinks"
+RemoveLinksAccesskey=n
+RemoveLinks=Tynnu Dolenni
+StopLinks=Peidio Parhau gyda'r Ddolen
+#
+NoFormAction=Awgrymir eich bod yn rhoi gweithred ar gyfer y ffurflen. Nid yw ffurflenni hunan gofnodi'n gweithio ar bob porwr am ei fod yn dechneg flaengar.
+NoAltText=Argymhellir eich bod yn darparu testun arall fydd yn ymddangos mewn porwyr testun yn unig, a fydd hefyd yn ymddangos mewn porwyr eraill pan fydd delwedd yn llwytho neu pan fo llwytho delwedd wedi'i analluogi.
+#
+Malformed=Nid oedd modd trosi'r ffynhonnell yn ôl i'r ddogfen am nad yw'n XHTML dilys.
+NoLinksToCheck=Does dim elfennau gyda chysylltiadau i'w gwirio
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/editorOverlay.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/editorOverlay.dtd
new file mode 100644
index 0000000000..d0e99b0b6d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/editorOverlay.dtd
@@ -0,0 +1,303 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Attn: Localization - some of the menus in this dialog directly affect mail also. -->
+
+<!-- Edit menu items -->
+<!ENTITY pasteNoFormatting.label "Gludo heb fformatio">
+<!ENTITY pasteNoFormatting.accesskey "G">
+<!ENTITY pasteNoFormatting.key "V">
+<!ENTITY pasteAsQuotationCmd.label "Gludo fel Dyfyniad">
+<!ENTITY pasteAsQuotationCmd.accesskey "D">
+
+<!-- Insert menu items -->
+<!ENTITY insertMenu.label "Mewnosod">
+<!ENTITY insertMenu.accesskey "M">
+<!ENTITY insertLinkCmd2.label "Dolen…">
+<!ENTITY insertLinkCmd2.accesskey "D">
+<!ENTITY insertLinkCmd2.key "K">
+<!ENTITY insertAnchorCmd.label "Angor a Enwyd…">
+<!ENTITY insertAnchorCmd.accesskey "A">
+<!ENTITY insertImageCmd.label "Delwedd…">
+<!ENTITY insertImageCmd.accesskey "D">
+<!ENTITY insertHLineCmd.label "Llinell Llorweddol">
+<!ENTITY insertHLineCmd.accesskey "l">
+<!ENTITY insertTableCmd.label "Tabl…">
+<!ENTITY insertTableCmd.accesskey "T">
+<!ENTITY insertHTMLCmd.label "HTML…">
+<!ENTITY insertHTMLCmd.accesskey "H">
+<!ENTITY insertMathCmd.label "Mathemateg…">
+<!ENTITY insertMathCmd.accesskey "M">
+<!ENTITY insertCharsCmd.label "Nodau a Symbolau…">
+<!ENTITY insertCharsCmd.accesskey "N">
+<!ENTITY insertBreakAllCmd.label "Toriad Islaw Delwedd(au)">
+<!ENTITY insertBreakAllCmd.accesskey "I">
+
+<!-- Used just in context popup. -->
+<!ENTITY createLinkCmd.label "Creu Dolen…">
+<!ENTITY createLinkCmd.accesskey "D">
+<!ENTITY editLinkCmd.label "Golygu'r ddolen o fewn Cyfansoddwr Newydd">
+<!ENTITY editLinkCmd.accesskey "G">
+
+<!-- Font Face SubMenu -->
+<!ENTITY FontFaceSelect.tooltip "Dewiswch ffont">
+<!ENTITY fontfaceMenu.label "Ffont">
+<!ENTITY fontfaceMenu.accesskey "F">
+<!ENTITY fontVarWidth.label "Lled Newidiol">
+<!ENTITY fontVarWidth.accesskey "N">
+<!ENTITY fontFixedWidth.label "Lled Osodedig">
+<!ENTITY fontFixedWidth.accesskey "O">
+<!ENTITY fontFixedWidth.key "T">
+<!ENTITY fontHelvetica.label "Helvetica, Arial">
+<!ENTITY fontHelvetica.accesskey "l">
+<!ENTITY fontTimes.label "Times">
+<!ENTITY fontTimes.accesskey "T">
+<!ENTITY fontCourier.label "Courier">
+<!ENTITY fontCourier.accesskey "C">
+
+<!-- Font Size SubMenu -->
+<!ENTITY FontSizeSelect.tooltip "Dewiswch faint y ffont">
+<!ENTITY decreaseFontSize.label "Llai">
+<!ENTITY decreaseFontSize.accesskey "L">
+<!ENTITY decrementFontSize.key "&lt;">
+<!ENTITY decrementFontSize.key2 ","> <!-- < is above this key on many keyboards -->
+<!ENTITY increaseFontSize.label "Mwy">
+<!ENTITY increaseFontSize.accesskey "M">
+<!ENTITY incrementFontSize.key "&gt;">
+<!ENTITY incrementFontSize.key2 "."> <!-- > is above this key on many keyboards -->
+
+<!ENTITY fontSizeMenu.label "Maint">
+<!ENTITY fontSizeMenu.accesskey "M">
+<!ENTITY size-tinyCmd.label "Bach Iawn">
+<!ENTITY size-tinyCmd.accesskey "I">
+<!ENTITY size-smallCmd.label "Bach">
+<!ENTITY size-smallCmd.accesskey "B">
+<!ENTITY size-mediumCmd.label "Canolig">
+<!ENTITY size-mediumCmd.accesskey "C">
+<!ENTITY size-largeCmd.label "Mawr">
+<!ENTITY size-largeCmd.accesskey "M">
+<!ENTITY size-extraLargeCmd.label "Mawr Iawn">
+<!ENTITY size-extraLargeCmd.accesskey "w">
+<!ENTITY size-hugeCmd.label "Anferth">
+<!ENTITY size-hugeCmd.accesskey "A">
+
+<!-- Font Style SubMenu -->
+<!ENTITY fontStyleMenu.label "Arddull Testun">
+<!ENTITY fontStyleMenu.accesskey "A">
+<!ENTITY styleBoldCmd.label "Trwm">
+<!ENTITY styleBoldCmd.accesskey "T">
+<!ENTITY styleBoldCmd.key "B">
+<!ENTITY styleItalicCmd.label "Italig">
+<!ENTITY styleItalicCmd.accesskey "I">
+<!ENTITY styleItalicCmd.key "I">
+<!ENTITY styleUnderlineCmd.label "Tanlinellu">
+<!ENTITY styleUnderlineCmd.accesskey "a">
+<!ENTITY styleUnderlineCmd.key "U">
+<!ENTITY styleStrikeThruCmd.label "Taro drwodd">
+<!ENTITY styleStrikeThruCmd.accesskey "o">
+<!ENTITY styleSuperscriptCmd.label "Uwchysgrif">
+<!ENTITY styleSuperscriptCmd.accesskey "U">
+<!ENTITY styleSubscriptCmd.label "Isysgrif">
+<!ENTITY styleSubscriptCmd.accesskey "I">
+<!ENTITY styleNonbreakingCmd.label "Ddim yn torri">
+<!ENTITY styleNonbreakingCmd.accesskey "D">
+<!ENTITY styleEm.label "Pwyslais">
+<!ENTITY styleEm.accesskey "P">
+<!ENTITY styleStrong.label "Pwyslais Cryfach">
+<!ENTITY styleStrong.accesskey "C">
+<!ENTITY styleCite.label "Dyfyniad">
+<!ENTITY styleCite.accesskey "D">
+<!ENTITY styleAbbr.label "Byrfodd">
+<!ENTITY styleAbbr.accesskey "B">
+<!ENTITY styleAcronym.label "Acronym">
+<!ENTITY styleAcronym.accesskey "A">
+<!ENTITY styleCode.label "Cod">
+<!ENTITY styleCode.accesskey "o">
+<!ENTITY styleSamp.label "Sampl Allbwn">
+<!ENTITY styleSamp.accesskey "S">
+<!ENTITY styleVar.label "Newidiol">
+<!ENTITY styleVar.accesskey "N">
+
+<!ENTITY formatFontColor.label "Lliw'r Testun…">
+<!ENTITY formatFontColor.accesskey "L">
+<!ENTITY tableOrCellColor.label "Lliw Cefndir y Tabl neu'r Gell…">
+<!ENTITY tableOrCellColor.accesskey "C">
+
+<!ENTITY formatRemoveStyles.key "Y">
+<!ENTITY formatRemoveLinks.key "K">
+<!ENTITY formatRemoveNamedAnchors.label "Tynnu Angorau Enwyd">
+<!ENTITY formatRemoveNamedAnchors.accesskey "T">
+<!ENTITY formatRemoveNamedAnchors2.key "R">
+
+<!ENTITY paragraphMenu.label "Paragraff">
+<!ENTITY paragraphMenu.accesskey "P">
+<!ENTITY paragraphParagraphCmd.label "Paragraff">
+<!ENTITY paragraphParagraphCmd.accesskey "P">
+<!ENTITY heading1Cmd.label "Pennyn 1">
+<!ENTITY heading1Cmd.accesskey "1">
+<!ENTITY heading2Cmd.label "Pennyn 2">
+<!ENTITY heading2Cmd.accesskey "2">
+<!ENTITY heading3Cmd.label "Pennyn 3">
+<!ENTITY heading3Cmd.accesskey "3">
+<!ENTITY heading4Cmd.label "Pennyn 4">
+<!ENTITY heading4Cmd.accesskey "4">
+<!ENTITY heading5Cmd.label "Pennyn 5">
+<!ENTITY heading5Cmd.accesskey "5">
+<!ENTITY heading6Cmd.label "Pennyn 6">
+<!ENTITY heading6Cmd.accesskey "6">
+<!ENTITY paragraphAddressCmd.label "Cyfeiriad">
+<!ENTITY paragraphAddressCmd.accesskey "C">
+<!ENTITY paragraphPreformatCmd.label "Rhagfformatio">
+<!ENTITY paragraphPreformatCmd.accesskey "R">
+
+<!-- List menu items -->
+<!ENTITY formatlistMenu.label "Rhestr">
+<!ENTITY formatlistMenu.accesskey "R">
+<!ENTITY noneCmd.label "Dim">
+<!ENTITY noneCmd.accesskey "D">
+<!ENTITY listBulletCmd.label "Bwledwyd">
+<!ENTITY listBulletCmd.accesskey "B">
+<!ENTITY listNumberedCmd.label "Rhifwyd">
+<!ENTITY listNumberedCmd.accesskey "R">
+<!ENTITY listTermCmd.label "Term">
+<!ENTITY listTermCmd.accesskey "T">
+<!ENTITY listDefinitionCmd.label "Diffiniad">
+<!ENTITY listDefinitionCmd.accesskey "D">
+<!ENTITY listPropsCmd.label "Priodweddau'r Rhestr…">
+<!ENTITY listPropsCmd.accesskey "R">
+
+<!ENTITY ParagraphSelect.tooltip "Dewiswch fformat paragraff">
+<!-- Shared in Paragraph, and Toolbar menulist -->
+<!ENTITY bodyTextCmd.label "Corff y Testun">
+<!ENTITY bodyTextCmd.accesskey "C">
+
+<!-- Align menu items -->
+<!ENTITY alignMenu.label "Alinio">
+<!ENTITY alignMenu.accesskey "A">
+<!ENTITY alignLeft.label "Chwith">
+<!ENTITY alignLeft.accesskey "C">
+<!ENTITY alignLeft.tooltip "Alinio i'r Chwith">
+<!ENTITY alignCenter.label "Canol">
+<!ENTITY alignCenter.accesskey "a">
+<!ENTITY alignCenter.tooltip "Alinio i'r Canol">
+<!ENTITY alignRight.label "De">
+<!ENTITY alignRight.accesskey "D">
+<!ENTITY alignRight.tooltip "Alinio i'r Dde">
+<!ENTITY alignJustify.label "Unioni">
+<!ENTITY alignJustify.accesskey "U">
+<!ENTITY alignJustify.tooltip "Alinio Unioni">
+
+<!ENTITY increaseIndent.label "Cynyddu'r Mewnoliad">
+<!ENTITY increaseIndent.accesskey "y">
+<!ENTITY increaseIndent.key "]">
+<!ENTITY decreaseIndent.label "Lleihau Mewnoliad">
+<!ENTITY decreaseIndent.accesskey "L">
+<!ENTITY decreaseIndent.key "[">
+
+<!ENTITY colorsAndBackground.label "Lliwiau Tudalen a Chefndir…">
+<!ENTITY colorsAndBackground.accesskey "L">
+
+<!-- Table Menu -->
+<!ENTITY tableMenu.label "Tabl">
+<!ENTITY tableMenu.accesskey "b">
+
+<!-- Select Submenu -->
+<!ENTITY tableSelectMenu.label "Dewis">
+<!ENTITY tableSelectMenu.accesskey "D">
+
+<!ENTITY tableSelectMenu2.label "Dewis Tabl">
+<!ENTITY tableSelectMenu2.accesskey "T">
+<!ENTITY tableInsertMenu2.label "Mewnosod Tabl">
+<!ENTITY tableInsertMenu2.accesskey "M">
+<!ENTITY tableDeleteMenu2.label "Dileu Tabl">
+<!ENTITY tableDeleteMenu2.accesskey "D">
+
+<!-- Insert SubMenu -->
+<!ENTITY tableInsertMenu.label "Mewnosod">
+<!ENTITY tableInsertMenu.accesskey "M">
+<!ENTITY tableTable.label "Tabl">
+<!ENTITY tableTable.accesskey "T">
+<!ENTITY tableRow.label "Rhes">
+<!ENTITY tableRows.label "Rhes(i)">
+<!ENTITY tableRow.accesskey "R">
+<!ENTITY tableRowAbove.label "Rhes Uwchben">
+<!ENTITY tableRowAbove.accesskey "U">
+<!ENTITY tableRowBelow.label "Rhes Islaw">
+<!ENTITY tableRowBelow.accesskey "I">
+<!ENTITY tableColumn.label "Colofn">
+<!ENTITY tableColumns.label "Colofn(au)">
+<!ENTITY tableColumn.accesskey "o">
+<!ENTITY tableColumnBefore.label "Colofn Cynt">
+<!ENTITY tableColumnBefore.accesskey "y">
+<!ENTITY tableColumnAfter.label "Colofn yn Dilyn">
+<!ENTITY tableColumnAfter.accesskey "D">
+<!ENTITY tableCell.label "Cell">
+<!ENTITY tableCells.label "Cell(oedd)">
+<!ENTITY tableCell.accesskey "C">
+<!ENTITY tableCellContents.label "Cynnwys Cell">
+<!ENTITY tableCellContents.accesskey "y">
+<!ENTITY tableAllCells.label "Pob Cell">
+<!ENTITY tableAllCells.accesskey "P">
+<!ENTITY tableCellBefore.label "Cell Cynt">
+<!ENTITY tableCellBefore.accesskey "e">
+<!ENTITY tableCellAfter.label "Cell yn Dilyn">
+<!ENTITY tableCellAfter.accesskey "i">
+<!-- Delete SubMenu -->
+<!ENTITY tableDeleteMenu.label "Dileu">
+<!ENTITY tableDeleteMenu.accesskey "D">
+
+<!-- text for "Join Cells" is in editor.properties
+     ("JoinSelectedCells" and "JoinCellToRight")
+     the access key must exist in both of those strings
+     But value must be set here for accesskey to draw properly
+-->
+<!ENTITY tableJoinCells.label "j">
+<!ENTITY tableJoinCells.accesskey "j">
+<!ENTITY tableSplitCell.label "Rhannu Cell">
+<!ENTITY tableSplitCell.accesskey "R">
+<!ENTITY convertToTable.label "Creu Tabl o'r Dewis">
+<!ENTITY convertToTable.accesskey "D">
+<!ENTITY tableProperties.label "Priodweddau Tabl…">
+<!ENTITY tableProperties.accesskey "P">
+
+<!ENTITY imageToolbarCmd.label "Delwedd">
+<!ENTITY imageToolbarCmd.tooltip "Mewnosod delwedd newydd neu olygu priodweddau'r ddelwedd">
+<!ENTITY hruleToolbarCmd.label "H.Line">
+<!ENTITY hruleToolbarCmd.tooltip "Mewnosod llinell lorweddol neu olygu priodweddau'r ddelwedd">
+<!ENTITY tableToolbarCmd.label "Tabl">
+<!ENTITY tableToolbarCmd.tooltip "Mewnosod tabl newydd neu olygu priodweddau'r tabl">
+<!ENTITY linkToolbarCmd.label "Dolen">
+<!ENTITY linkToolbarCmd.tooltip "Mewnosod dolen newydd neu olygu priodweddau'r ddolen">
+<!ENTITY anchorToolbarCmd.label "Angor">
+<!ENTITY anchorToolbarCmd.tooltip "Mewnosod angor a enwyd neu olygu priodweddau'r angor">
+<!ENTITY TextColorButton.tooltip "Dewiswch liw i'r testun">
+<!ENTITY BackgroundColorButton.tooltip "Dewiswch liw i'r cefndir">
+
+<!-- Editor toolbar -->
+<!ENTITY absoluteFontSizeToolbarCmd.tooltip "Gosod maint ffont">
+<!ENTITY decreaseFontSizeToolbarCmd.tooltip "Maint ffont lai">
+<!ENTITY increaseFontSizeToolbarCmd.tooltip "Maint ffont mwy">
+<!ENTITY boldToolbarCmd.tooltip "Trwm">
+<!ENTITY italicToolbarCmd.tooltip "Italig">
+<!ENTITY underlineToolbarCmd.tooltip "Tanlinellu">
+<!ENTITY bulletListToolbarCmd.tooltip "Gosod neu ddiddymu rhestr bwledi">
+<!ENTITY numberListToolbarCmd.tooltip "Gosod neu ddiddymu rhestr rhifedig">
+<!ENTITY outdentToolbarCmd.tooltip "Alloliad testun (symud i'r chwith)">
+<!ENTITY indentToolbarCmd.tooltip "Mewnoliad testun (symud i'r dde)">
+<!ENTITY AlignPopupButton.tooltip "Dewis aliniad testun">
+<!ENTITY InsertPopupButton.tooltip "Mewnosod Dolen, Angor, Delwedd, Llinell Lorweddol neu Dabl">
+<!ENTITY alignLeftButton.tooltip "Alinio testun ar hyd yr ymyl chwith">
+<!ENTITY alignCenterButton.tooltip "Alinio testun wedi'i ganoli">
+<!ENTITY alignRightButton.tooltip "Alinio testun ar hyd yr ymyl dde">
+<!ENTITY alignJustifyButton.tooltip "Alinio testun ar hyd ymylon de a chwith">
+
+<!-- TOC manipulation -->
+<!ENTITY insertTOC.label          "Mewnosod">
+<!ENTITY insertTOC.accesskey      "M">
+<!ENTITY updateTOC.label          "Diweddaru">
+<!ENTITY updateTOC.accesskey      "u">
+<!ENTITY removeTOC.label          "Tynnu">
+<!ENTITY removeTOC.accesskey      "T">
+<!ENTITY tocMenu.label            "Tabl Cynnwys…">
+<!ENTITY tocMenu.accesskey        "C">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/mailComposeEditorOverlay.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/mailComposeEditorOverlay.dtd
new file mode 100644
index 0000000000..331520180c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/mailComposeEditorOverlay.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY attachImageSource.label         "Atodi'r ddelwedd i'r neges">
+<!ENTITY attachImageSource.accesskey     "d">
+
+<!ENTITY attachLinkSource.label          "Atodi ffynhonnell y ddolen i'r neges">
+<!ENTITY attachLinkSource.accesskey      "f">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/messengercompose.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/messengercompose.dtd
new file mode 100644
index 0000000000..3af55b90c0
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/messengercompose.dtd
@@ -0,0 +1,345 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE messengercompose.dtd Main UI for message composition -->
+<!ENTITY msgComposeWindow.title "Ysgrifennu: (dim pwnc)">
+
+<!-- File Menu -->
+<!ENTITY fileMenu.label "Ffeil">
+<!ENTITY fileMenu.accesskey "F">
+<!ENTITY newMenu.label "Newydd">
+<!ENTITY newMenu.accesskey "N">
+<!ENTITY newMessage.label "Neges">
+<!ENTITY newMessage.key "M">
+<!ENTITY newMessageCmd2.key "N">
+<!ENTITY newMessage.accesskey "e">
+<!ENTITY newContact.label "Cysylltiad Llyfr Cyfeiriadau…">
+<!ENTITY newContact.accesskey "C">
+<!ENTITY attachMenu.label "Atodi">
+<!ENTITY attachMenu.accesskey "A">
+<!ENTITY attachFileCmd.label "Ffeil(iau)…">
+<!ENTITY attachFileCmd.accesskey "F">
+<!ENTITY attachFileCmd.key "A">
+<!ENTITY attachCloudCmd.label "Filelink">
+<!ENTITY attachCloudCmd.accesskey "F">
+<!ENTITY attachPageCmd.label "Tudalen Gwe…">
+<!ENTITY attachPageCmd.accesskey "T">
+<!--LOCALIZATION NOTE attachVCardCmd.label Don't translate the term 'vCard' -->
+<!ENTITY attachVCardCmd.label "Cerdyn Personol (vCard)">
+<!ENTITY attachVCardCmd.accesskey "C">
+<!ENTITY remindLater.label "Atgoffa Fi yn Ddiweddarach">
+<!ENTITY remindLater.accesskey "D">
+<!ENTITY closeCmd.label "Cau">
+<!ENTITY closeCmd.key "W">
+<!ENTITY closeCmd.accesskey "u">
+<!ENTITY saveCmd.label "Cadw">
+<!ENTITY saveCmd.key "S">
+<!ENTITY saveCmd.accesskey "C">
+<!ENTITY saveAsCmd.label "Cadw Fel">
+<!ENTITY saveAsCmd.accesskey "d">
+<!ENTITY saveAsFileCmd.label "Ffeil…">
+<!ENTITY saveAsFileCmd.accesskey "F">
+<!ENTITY saveAsDraftCmd.label "Drafft">
+<!ENTITY saveAsDraftCmd.accesskey "D">
+<!ENTITY saveAsTemplateCmd.label "Templed">
+<!ENTITY saveAsTemplateCmd.accesskey "T">
+<!ENTITY sendNowCmd.label "Anfon Nawr">
+<!ENTITY sendCmd.keycode "VK_RETURN">
+<!ENTITY sendNowCmd.accesskey "A">
+<!ENTITY sendLaterCmd.label "Anfon yn Diweddarach">
+<!ENTITY sendLaterCmd.keycode "VK_RETURN">
+<!ENTITY sendLaterCmd.accesskey "D">
+<!ENTITY printSetupCmd.label "Gosodiad Tudalen…">
+<!ENTITY printSetupCmd.accesskey "u">
+<!ENTITY printPreviewCmd.label "Rhagolwg Argraffu">
+<!ENTITY printPreviewCmd.accesskey "R">
+<!ENTITY printCmd.label "Argraffu…">
+<!ENTITY printCmd.key "P">
+<!ENTITY printCmd.accesskey "A">
+
+<!-- Edit Menu -->
+<!ENTITY editMenu.label "Golygu">
+<!ENTITY editMenu.accesskey "G">
+<!ENTITY undoCmd.label "Dadwneud">
+<!ENTITY undoCmd.key "Z">
+<!ENTITY undoCmd.accesskey "u">
+<!ENTITY redoCmd.label "Ailwneud">
+<!ENTITY redoCmd.key "Y">
+<!ENTITY redoCmd.accesskey "A">
+<!ENTITY cutCmd.key "X">
+<!ENTITY copyCmd.key "C">
+<!ENTITY pasteCmd.key "V">
+<!ENTITY pasteNoFormattingCmd.key "V">
+<!ENTITY pasteAsQuotationCmd.key "o">
+<!ENTITY editRewrapCmd.accesskey "i">
+<!ENTITY deleteCmd.label "Dileu">
+<!ENTITY deleteCmd.accesskey "D">
+<!ENTITY editRewrapCmd.label "Ail-lapio">
+<!ENTITY editRewrapCmd.key "R">
+<!ENTITY renameAttachmentCmd.label "Ailenwi Atodiad…">
+<!ENTITY renameAttachmentCmd.accesskey "A">
+<!ENTITY reorderAttachmentsCmd.label "Aildrefnu Atodiadau…">
+<!ENTITY reorderAttachmentsCmd.accesskey "A">
+<!ENTITY reorderAttachmentsCmd.key "x">
+<!ENTITY toggleAttachmentPaneCmd.label "Paen Atodiad">
+<!ENTITY toggleAttachmentPaneCmd.accesskey "A">
+<!ENTITY selectAllCmd.accesskey "D">
+<!ENTITY findBarCmd.label "Canfod…">
+<!ENTITY findBarCmd.accesskey "f">
+<!ENTITY findBarCmd.key "F">
+<!ENTITY findReplaceCmd.label "Canfod ac Amnewid…">
+<!ENTITY findReplaceCmd.accesskey "N">
+<!ENTITY findReplaceCmd.key "H">
+<!ENTITY findAgainCmd.label "Canfod Eto">
+<!ENTITY findAgainCmd.accesskey "E">
+<!ENTITY findAgainCmd.key "G">
+<!ENTITY findAgainCmd.key2 "VK_F3">
+<!ENTITY findPrevCmd.label "Canfod Blaenorol">
+<!ENTITY findPrevCmd.accesskey "B">
+<!ENTITY findPrevCmd.key "G">
+<!ENTITY findPrevCmd.key2 "VK_F3">
+
+<!-- Reorder Attachment Panel -->
+<!ENTITY reorderAttachmentsPanel.label "Aildrefnu Atodiadau">
+<!ENTITY moveAttachmentTopPanelBtn.label "Symud i'r Brig">
+<!ENTITY moveAttachmentUpPanelBtn.label "Symud i Fyny">
+<!ENTITY moveAttachmentBundleUpPanelBtn.label "Symud gyda'i gilydd">
+<!ENTITY moveAttachmentDownPanelBtn.label "Symud i Lawr">
+<!ENTITY moveAttachmentBottomPanelBtn.label "Symud i'r Gwaelod">
+
+<!-- LOCALIZATION NOTE (sortAttachmentsPanelBtn.Sort.AZ.label):
+     Please ensure that this translation matches
+     sortAttachmentsPanelBtn.Sort.ZA.label, except for the sort direction. -->
+<!ENTITY sortAttachmentsPanelBtn.Sort.AZ.label "Trefnu: A - Z">
+<!ENTITY sortAttachmentsPanelBtn.Sort.ZA.label "Trefnu: Z - A">
+<!-- LOCALIZATION NOTE (sortAttachmentsPanelBtn.SortSelection.AZ.label):
+     Please ensure that this translation matches
+     sortAttachmentsPanelBtn.SortSelection.ZA.label, except for the sort direction. -->
+<!ENTITY sortAttachmentsPanelBtn.SortSelection.AZ.label "Trefnu'r Dewis: A - Z">
+<!ENTITY sortAttachmentsPanelBtn.SortSelection.ZA.label "Trefnu'r Dewis: Z - A">
+<!ENTITY sortAttachmentsPanelBtn.key "t">
+
+<!-- View Menu -->
+<!ENTITY viewMenu.label "Golwg">
+<!ENTITY viewMenu.accesskey "l">
+<!ENTITY viewToolbarsMenuNew.label "Barrau Offer">
+<!ENTITY viewToolbarsMenuNew.accesskey "B">
+<!ENTITY menubarCmd.label "Bar Dewislen">
+<!ENTITY menubarCmd.accesskey "D">
+<!ENTITY showCompositionToolbarCmd.label "Bar Offer Ysgrifennu">
+<!ENTITY showCompositionToolbarCmd.accesskey "Y">
+<!ENTITY showFormattingBarCmd.label "Bar Offer Fformatio">
+<!ENTITY showFormattingBarCmd.accesskey "F">
+<!ENTITY showTaskbarCmd.label "Bar Statws">
+<!ENTITY showTaskbarCmd.accesskey "S">
+<!ENTITY customizeToolbar.label "Cyfaddasu…">
+<!ENTITY customizeToolbar.accesskey "C">
+
+<!ENTITY addressSidebar.label "Bar Ochr Cysylltiadau">
+<!ENTITY addressSidebar.accesskey "O">
+
+<!-- Format Menu -->
+<!ENTITY formatMenu.label "Fformat">
+<!ENTITY formatMenu.accesskey "o">
+
+<!-- Options Menu -->
+<!ENTITY optionsMenu.label "Dewisiadau">
+<!ENTITY optionsMenu.accesskey "D">
+<!ENTITY checkSpellingCmd2.label "Gwirio Sillafu…">
+<!ENTITY checkSpellingCmd2.key "p">
+<!ENTITY checkSpellingCmd2.key2 "VK_F7">
+<!ENTITY checkSpellingCmd2.accesskey "G">
+<!ENTITY enableInlineSpellChecker.label "Gwirio Sillafu wrth Deipio">
+<!ENTITY enableInlineSpellChecker.accesskey "D">
+<!ENTITY quoteCmd.label "Dyfynnu Neges">
+<!ENTITY quoteCmd.accesskey "N">
+
+<!--LOCALIZATION NOTE attachVCard.label Don't translate the term 'vCard' -->
+<!ENTITY attachVCard.label "Atodi Cerdyn Personol (vCard)">
+<!ENTITY attachVCard.accesskey "v">
+
+<!ENTITY returnReceiptMenu.label "Derbynneb Dychwelyd">
+<!ENTITY returnReceiptMenu.accesskey "D">
+<!ENTITY dsnMenu.label "Hysbysiad Statws Trosglwyddo">
+<!ENTITY dsnMenu.accesskey "H">
+<!ENTITY deliveryFormatMenu.label "Fformat Darparu">
+<!ENTITY deliveryFormatMenu.accesskey "D">
+<!ENTITY autoFormatCmd.label "Awto-Ganfod">
+<!ENTITY autoFormatCmd.accesskey "A">
+<!ENTITY plainTextFormatCmd.label "Testun Plaen yn Unig">
+<!ENTITY plainTextFormatCmd.accesskey "P">
+<!ENTITY htmlFormatCmd.label "Testun Cyfoethog (HTML) yn Unig">
+<!ENTITY htmlFormatCmd.accesskey "C">
+<!ENTITY bothFormatCmd.label "Testun Plaen a Chyfoethog (HTML)">
+<!ENTITY bothFormatCmd.accesskey "P">
+<!ENTITY priorityMenu.label "Blaenoriaeth">
+<!ENTITY priorityMenu.accesskey "B">
+<!ENTITY priorityButton.title "Blaenoriaeth">
+<!ENTITY priorityButton.tooltiptext "Newid blaenoriaethau negeseuon">
+<!ENTITY priorityButton.label "Blaenoriaeth:">
+<!ENTITY lowestPriorityCmd.label "Isaf">
+<!ENTITY lowestPriorityCmd.accesskey "I">
+<!ENTITY lowPriorityCmd.label "Isel">
+<!ENTITY lowPriorityCmd.accesskey "s">
+<!ENTITY normalPriorityCmd.label "Arferol">
+<!ENTITY normalPriorityCmd.accesskey "A">
+<!ENTITY highPriorityCmd.label "Uchel">
+<!ENTITY highPriorityCmd.accesskey "c">
+<!ENTITY highestPriorityCmd.label "Uchaf">
+<!ENTITY highestPriorityCmd.accesskey "U">
+<!ENTITY fileCarbonCopyCmd.label "Anfon Copi At">
+<!ENTITY fileCarbonCopyCmd.accesskey "A">
+<!ENTITY fileHereMenu.label "Ffeilio Yma">
+
+<!-- Tools Menu -->
+<!ENTITY tasksMenu.label "Offer">
+<!ENTITY tasksMenu.accesskey "O">
+<!ENTITY messengerCmd.label "E-bost a Grwpiau Newyddion">
+<!ENTITY messengerCmd.accesskey "b">
+<!ENTITY messengerCmd.commandkey "1">
+<!ENTITY addressBookCmd.label "Llyfr Cyfeiriadau">
+<!ENTITY addressBookCmd.accesskey "L">
+<!ENTITY addressBookCmd.key "B">
+<!ENTITY accountManagerCmd2.label "Gosodiadau'r Cyfrif">
+<!ENTITY accountManagerCmd2.accesskey "C">
+<!ENTITY accountManagerCmdUnix2.accesskey "C">
+<!ENTITY preferencesCmd2.label "Dewisiadau">
+<!ENTITY preferencesCmd2.accesskey "D">
+<!ENTITY preferencesCmdUnix.label "Dewisiadau">
+<!ENTITY preferencesCmdUnix.accesskey "e">
+
+<!--  Mac OS X Window Menu -->
+<!ENTITY minimizeWindow.key "m">
+<!ENTITY minimizeWindow.label "Lleihau">
+<!ENTITY bringAllToFront.label "Dod â'r Cyfan i'r Blaen">
+<!ENTITY zoomWindow.label "Chwyddo">
+<!ENTITY windowMenu.label "Ffenestr">
+
+<!-- Mail Toolbar -->
+<!ENTITY sendButton.label "Anfon">
+<!ENTITY quoteButton.label "Dyfynnu">
+<!ENTITY addressButton.label "Cysylltiadau">
+<!ENTITY attachButton.label "Atodi">
+<!ENTITY spellingButton.label "Sillafu">
+<!ENTITY saveButton.label "Cadw">
+<!ENTITY printButton.label "Argraffu">
+
+<!-- Mail Toolbar Tooltips -->
+<!ENTITY sendButton.tooltip "Anfon y neges nawr">
+<!ENTITY sendlaterButton.tooltip "Anfonwch y neges yn ddiweddarach">
+<!ENTITY quoteButton.tooltip "Dyfynnu'r neges flaenorol">
+<!ENTITY addressButton.tooltip "Dewis derbynnydd o'r Llyfr Cyfeiriadau">
+<!ENTITY attachButton.tooltip2 "Ychwanegu atodiad">
+<!ENTITY spellingButton.tooltip "Gwirio sillafu adran neu neges gyfan">
+<!ENTITY saveButton.tooltip "Cadw'r neges">
+<!ENTITY cutButton.tooltip              "Torri">
+<!ENTITY copyButton.tooltip             "Copïo">
+<!ENTITY pasteButton.tooltip            "Gludo">
+<!ENTITY printButton.tooltip "Argraffu'r neges">
+
+<!-- Headers -->
+<!--LOCALIZATION NOTE headersSpaces.style is for aligning  the From:, To: and
+    Subject: rows. It should be larger than the largest Header label  -->
+<!ENTITY headersSpace2.style "width: 8em;">
+<!ENTITY extraRecipients.tooltip "Mathau eraill o feysydd cyfeiriad">
+<!ENTITY fromAddr2.label "Oddi wrth">
+<!ENTITY fromAddr.accesskey "O">
+<!ENTITY toAddr2.label "At">
+<!ENTITY ccAddr2.label "Cc">
+<!ENTITY bccAddr2.label "Bcc">
+<!ENTITY replyAddr2.label "Ateb i">
+<!ENTITY newsgroupsAddr2.label "Grŵp Newyddion">
+<!ENTITY followupAddr2.label "Dilyn i">
+<!ENTITY subject2.label "Pwnc">
+<!ENTITY subject.accesskey "P">
+<!ENTITY attachmentBucketCloseButton.tooltip "Cuddio'r paen atodiad">
+
+<!-- Format Toolbar, imported from editorAppShell.xhtml -->
+<!ENTITY SmileButton.tooltip "Mewnosod wyneb gwenog">
+<!ENTITY smiley1Cmd.label "Gwên">
+<!ENTITY smiley2Cmd.label "Gwg">
+<!ENTITY smiley3Cmd.label "Winc">
+<!ENTITY smiley4Cmd.label "Tafod allan">
+<!ENTITY smiley5Cmd.label "Chwerthin">
+<!ENTITY smiley6Cmd.label "Embaras">
+<!ENTITY smiley7Cmd.label "Heb benderfynu">
+<!ENTITY smiley8Cmd.label "Syndod">
+<!ENTITY smiley9Cmd.label "Cusan">
+<!ENTITY smiley10Cmd.label "Gwaedd">
+<!ENTITY smiley11Cmd.label "Cwl">
+<!ENTITY smiley12Cmd.label "Ceg Aur">
+<!ENTITY smiley13Cmd.label "Ceg Fawr">
+<!ENTITY smiley14Cmd.label "Diniwed">
+<!ENTITY smiley15Cmd.label "Crio">
+<!ENTITY smiley16Cmd.label "Dim Gair!">
+
+<!-- Message Pane Context Menu -->
+<!ENTITY spellCheckNoSuggestions.label "Heb Ganfod Awgrymiadau">
+<!ENTITY spellCheckIgnoreWord.label "Anwybyddu Gair">
+<!ENTITY spellCheckIgnoreWord.accesskey "A">
+<!ENTITY spellCheckAddToDictionary.label "Ychwanegu i'r Geiriadur">
+<!ENTITY spellCheckAddToDictionary.accesskey "n">
+<!ENTITY undo.label "Dadwneud">
+<!ENTITY undo.accesskey "u">
+<!ENTITY cut.label "Torri">
+<!ENTITY cut.accesskey "T">
+<!ENTITY copy.label "Copïo">
+<!ENTITY copy.accesskey "C">
+<!ENTITY paste.label "Gludo">
+<!ENTITY paste.accesskey "G">
+<!ENTITY pasteQuote.label "Gludo fel Dyfyniad">
+<!ENTITY pasteQuote.accesskey "D">
+
+<!-- Attachment Item and List Context Menus -->
+<!ENTITY openAttachment.label "Agor">
+<!ENTITY openAttachment.accesskey "o">
+<!ENTITY delete.label "Dileu">
+<!ENTITY delete.accesskey "D">
+<!ENTITY removeAttachment.label "Tynnu Atodiad">
+<!ENTITY removeAttachment.accesskey "y">
+<!ENTITY renameAttachment.label "Ailenwi…">
+<!ENTITY renameAttachment.accesskey "A">
+<!ENTITY reorderAttachments.label "Aildrefnu Atodiadau…">
+<!ENTITY reorderAttachments.accesskey "a">
+<!ENTITY removeAllAttachments.label "Tynnu Pob Atodiad">
+<!ENTITY removeAllAttachments.accesskey "T">
+<!ENTITY selectAll.label "Dewis Popeth">
+<!ENTITY selectAll.accesskey "D">
+<!ENTITY attachFile.label "Atodi Ffeil(iau)…">
+<!ENTITY attachFile.accesskey "F">
+<!ENTITY attachCloud.label "Filelink…">
+<!ENTITY attachCloud.accesskey "i">
+<!ENTITY convertCloud.label "Trosi i…">
+<!ENTITY convertCloud.accesskey "T">
+<!ENTITY cancelUpload.label "Diddymu'r Llwytho i Fyny">
+<!ENTITY cancelUpload.accesskey "D">
+<!ENTITY convertRegularAttachment.label "Atodiad Arferol">
+<!ENTITY convertRegularAttachment.accesskey "A">
+<!ENTITY attachPage.label "Atodi Tudalen Gwe…">
+<!ENTITY attachPage.accesskey "T">
+
+<!-- Attachment Pane Header Bar Context Menu -->
+<!-- LOCALIZATION NOTE (initiallyShowAttachmentPane.label):
+     Should use the same wording as startExpandedCmd.label
+     in msgHdrViewOverlay.dtd. -->
+<!ENTITY initiallyShowAttachmentPane.label "Dangos y Paen Atodi yn Gyntaf">
+<!ENTITY initiallyShowAttachmentPane.accesskey "D">
+
+<!-- Spell checker context menu items -->
+<!ENTITY spellAddDictionaries.label "Ychwanegu Geiriaduron…">
+<!ENTITY spellAddDictionaries.accesskey "G">
+
+<!-- Title for the address picker panel -->
+<!ENTITY addressesSidebarTitle.label "Cysylltiadau">
+
+<!-- Identity popup customize menuitem -->
+<!ENTITY customizeFromAddress.label "Cyfaddasu Cyfeiriad Oddi Wrth…">
+<!ENTITY customizeFromAddress.accesskey "O">
+
+<!-- Accessibility name for the document -->
+<!ENTITY aria.message.bodyName "Corff neges">
+
+<!-- Status Bar -->
+<!ENTITY languageStatusButton.tooltip "Iaith gwirio sillafu">
+<!ENTITY encodingStatusPanel.tooltip "Amgodiad testun">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.dtd b/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.dtd
new file mode 100644
index 0000000000..0bc736e9f1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.dtd
@@ -0,0 +1,8 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!--LOCALIZATION NOTE sendProgress.dtd Main UI for Send Message Progress Dialog -->
+
+<!ENTITY sendDialog.title "Prosesu Neges">
+<!ENTITY status.label "Statws:">
+<!ENTITY progress.label "Cynnydd:">
diff --git a/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.properties b/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.properties
new file mode 100644
index 0000000000..2682ce0cf3
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/messengercompose/sendProgress.properties
@@ -0,0 +1,21 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (titleSendMsgSubject):
+# %S will be replaced by the message subject.
+titleSendMsgSubject=Anfon Neges - %S
+titleSendMsg=Anfon Neges
+# LOCALIZATION NOTE (titleSaveMsgSubject):
+# %S will be replaced by the message subject.
+titleSaveMsgSubject=Cadw Neges - %S
+titleSaveMsg=Cadw Neges
+
+# LOCALIZATION NOTE (percentMsg):
+# This string is used to format the text to the right of the progress meter.
+# %S will be replaced by the percentage of the file that has been saved.
+# %% will be replaced a single % sign.
+percentMsg=%S%%
+
+messageSent=Mae eich negeseuon wedi'u hanfon.
+messageSaved=Mae eich negeseuon wedi'u cadw.
diff --git a/l10n-cy/mail/chrome/messenger/migration/migration.dtd b/l10n-cy/mail/chrome/messenger/migration/migration.dtd
new file mode 100644
index 0000000000..c971fb91ae
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/migration/migration.dtd
@@ -0,0 +1,30 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+
+<!ENTITY migrationWizard.title          "Dewin Mewnforio">
+
+<!ENTITY importFromWin.label            "Dewisiadau Mewnforio, Nodau Tudalen, Hanes, Cyfrineiriau, a data arall o:">
+<!ENTITY importFromNonWin.label         "Dewisiadau Mewnforio, Nodau Tudalen, Hanes, Cyfrineiriau a data arall o:">
+<!ENTITY importSourceNotFound.label     "Heb ganfod rhaglen i fewnforio data ohoni.">
+
+<!ENTITY importFromNothing.label        "Peidio mewnforio dim">
+<!ENTITY importFromNothing.accesskey    "P">
+<!ENTITY importFromSeamonkey3.label     "SeaMonkey 2 neu'r diweddarach">
+<!ENTITY importFromSeamonkey3.accesskey "S">
+<!ENTITY importFromOutlook.label        "Outlook">
+<!ENTITY importFromOutlook.accesskey    "O">
+
+<!ENTITY importSource.title             "Gosodiadau Mewnforio a Ffolderi E-bost">
+<!ENTITY importItems.title              "Eitemau i'w Mewnforio">
+<!ENTITY importItems.label              "Dewis eitemau i'w mewnforio:">
+
+<!ENTITY migrating.title                "Mewnforio…">
+<!ENTITY migrating.label                "Mae'r eitemau canlynol yn cael eu mewnforio…">
+
+<!ENTITY selectProfile.title            "Dewis Proffil">
+<!ENTITY selectProfile.label            "Mae'r proffiliau canlynol ar gael i'w mewnforio o:">
+
+<!ENTITY done.title                     "Wedi Cwblhau Mewnforio">
+<!ENTITY done.label                     "Cafodd yr eitemau canlynol eu mewnforio'n llwyddiannus:">
diff --git a/l10n-cy/mail/chrome/messenger/migration/migration.properties b/l10n-cy/mail/chrome/messenger/migration/migration.properties
new file mode 100644
index 0000000000..b74929dbc3
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/migration/migration.properties
@@ -0,0 +1,25 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+profileName_format=%S %S
+
+# Import Sources
+1_seamonkey=Dewisiadau
+
+2_seamonkey=Gosodiadau'r Cyfrif
+2_outlook=Gosodiadau'r Cyfrif
+
+4_seamonkey=Llyfrau Cyfeiriadau
+4_outlook=Llyfr Cyfeiriadau
+
+8_seamonkey=Hyfforddiant Sbam
+
+16_seamonkey=Cyfrineiriau a Gadwyd
+
+32_seamonkey=Data Arall
+
+64_seamonkey=Ffolderi Grwpiau Newyddion
+
+128_seamonkey=Ffolderi E-bost
+128_outlook=Ffolderi E-bost
diff --git a/l10n-cy/mail/chrome/messenger/mime.properties b/l10n-cy/mail/chrome/messenger/mime.properties
new file mode 100644
index 0000000000..f4e27121ca
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mime.properties
@@ -0,0 +1,154 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by libmime to emit header display in HTML
+#
+
+# Mail subject
+## @name MIME_MHTML_SUBJECT
+## @loc None
+1000=Pwnc
+
+# Resent-Comments
+## @name MIME_MHTML_RESENT_COMMENTS
+## @loc 
+1001=Ailanfonwyd-Sylwadau
+
+# Resent-Date
+## @name MIME_MHTML_RESENT_DATE
+## @loc 
+1002=Ailanfonwyd-Dyddiad
+
+# Resent-Sender
+## @name MIME_MHTML_RESENT_SENDER
+## @loc 
+1003=Ailanfonwyd-Anfonwr
+
+# Resent-From
+## @name MIME_MHTML_RESENT_FROM
+## @loc 
+1004=Ailanfonwyd-Oddi wrth
+
+# Resent-To
+## @name MIME_MHTML_RESENT_TO
+## @loc 
+1005=Ailanfonwyd-At
+
+# Resent-CC
+## @name MIME_MHTML_RESENT_CC
+## @loc 
+1006=Ailanfonwyd-CC
+
+# Date
+## @name MIME_MHTML_DATE
+## @loc 
+1007=Dyddiad
+
+# Sender
+## @name MIME_MHTML_SENDER
+## @loc 
+1008=Anfonwr
+
+# From
+## @name MIME_MHTML_FROM
+## @loc 
+1009=Oddi wrth
+
+# Reply-To
+## @name MIME_MHTML_REPLY_TO
+## @loc 
+1010=Ateb-At
+
+# Organization
+## @name MIME_MHTML_ORGANIZATION
+## @loc 
+1011=Corff
+
+# To
+## @name MIME_MHTML_TO
+## @loc 
+1012=I
+
+# CC
+## @name MIME_MHTML_CC
+## @loc 
+1013=CC
+
+# Newsgroups
+## @name MIME_MHTML_NEWSGROUPS
+## @loc 
+1014=Grwpiau Newyddion
+
+# Followup-To
+## @name MIME_MHTML_FOLLOWUP_TO
+## @loc 
+1015=Dilyn-At
+
+# References
+## @name MIME_MHTML_REFERENCES
+## @loc 
+1016=Cyfeirnodau
+
+# Message ID
+## @name MIME_MHTML_MESSAGE_ID
+## @loc 
+1021=Neges-Enw
+
+# BCC
+## @name MIME_MHTML_BCC
+## @loc 
+1023=BCC
+
+# Link to doc
+## @name MIME_MSG_LINK_TO_DOCUMENT
+## @loc 
+1026=Cysylltu â Ddogfen
+
+# Get Doc info
+## @name MIME_MSG_DOCUMENT_INFO
+## @loc 
+1027=<B>Gwybodaeth am Ddogfen:</B>
+
+# Msg Attachment
+## @name MIME_MSG_ATTACHMENT
+## @loc 
+1028=Atodiad
+
+# default attachment name
+## @name MIME_MSG_DEFAULT_ATTACHMENT_NAME
+## @loc 
+# LOCALIZATION NOTE (1040): Do not translate "%s" below.
+# Place the %s where you wish the part number of the attachment to appear
+1040=Rhan %s
+
+# default forwarded message prefix
+## @name MIME_FORWARDED_MESSAGE_HTML_USER_WROTE
+## @loc 
+1041=-------- Neges Wreiddiol --------
+
+# Partial Message Truncated
+## @name MIME_MSG_PARTIAL_TRUNCATED
+## @loc
+MIME_MSG_PARTIAL_TRUNCATED=Tociwyd!
+
+# Partial Message Truncated Explanation
+## @name MIME_MSG_PARTIAL_TRUNCATED_EXPLANATION
+## @loc
+MIME_MSG_PARTIAL_TRUNCATED_EXPLANATION=Mae'r neges yn fwy na Maint Neges Mwyaf osodwyd yn Osodiadau Cyfrif, felly dim ond y llinellau cyntaf sydd wedi cael eu llwytho i lawr o'r gweinydd e-bost.
+
+# Partial Message Not Downloaded
+## @name MIME_MSG_PARTIAL_NOT_DOWNLOADED
+## @loc
+MIME_MSG_PARTIAL_NOT_DOWNLOADED=Heb ei Lwytho i Lawr
+
+# Partial Message Not Downloaded Explanation
+## @name MIME_MSG_PARTIAL_NOT_DOWNLOADED_EXPLANATION
+## @loc
+MIME_MSG_PARTIAL_NOT_DOWNLOADED_EXPLANATION=Dim ond penynnau'r neges yma gafodd eu llwytho i lawr o'r gweinydd e-bost.
+
+# MIME_MSG_PARTIAL_CLICK_FOR_REST
+## @name MIME_MSG_PARTIAL_CLICK_FOR_REST
+## @loc
+MIME_MSG_PARTIAL_CLICK_FOR_REST=Llwytho i lawr gweddill y neges.
diff --git a/l10n-cy/mail/chrome/messenger/mimeheader.properties b/l10n-cy/mail/chrome/messenger/mimeheader.properties
new file mode 100644
index 0000000000..44e193e3d4
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/mimeheader.properties
@@ -0,0 +1,35 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by libmime for header display in XML & HTML
+#
+TO=At
+BCC=BCC
+CC=CC
+DATE=Dyddiad
+DISTRIBUTION=Dosbarthu
+FCC=FCC
+FOLLOWUP-TO=Dilyn-At
+FROM=Oddi wrth
+STATUS=Statws
+LINES=Llinellau
+MESSAGE-ID=Neges-Enw
+MIME-VERSION=MIME-Fersiwn
+NEWSGROUPS=Grwpiau Newyddion
+ORGANIZATION=Corff
+REFERENCES=Cyfeirnodau
+REPLY-TO=Ateb-At
+RESENT-COMMENTS=Ailanfonwyd-Sylwadau
+RESENT-DATE=Ailanfonwyd-Dyddiad
+RESENT-FROM=Ailanfonwyd-Oddi wrth
+RESENT-MESSAGE-ID=Ailanfonwyd-Neges-Enw
+RESENT-SENDER=Ailanfonwyd-Anfonwr
+RESENT-TO=Ailanfonwyd-At
+RESENT-CC=Ailanfonwyd-CC
+SENDER=Anfonwr
+SUBJECT=Pwnc
+APPROVED-BY=Cymeradwywyd-Gan
+USER-AGENT=Asiant-Defnyddiwr
+FILENAME=Enw ffeil
diff --git a/l10n-cy/mail/chrome/messenger/morkImportMsgs.properties b/l10n-cy/mail/chrome/messenger/morkImportMsgs.properties
new file mode 100644
index 0000000000..d3ea8d0c73
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/morkImportMsgs.properties
@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the Mork import code to display status/error
+# and informational messages.
+#
+
+MABFiles = Llyfrau Cyfeiriadau Mork
+
+# Short name of import module
+morkImportName = Cronfa ddata Mork (.mab)
+
+# Description of import module
+morkImportDescription = Mewnforio llyfr cyfeiriadau o SeaMonkey neu fersiynau cynharach o Thunderbird.
+
+morkImportSuccess = Llwyddiant!
diff --git a/l10n-cy/mail/chrome/messenger/msgAccountCentral.dtd b/l10n-cy/mail/chrome/messenger/msgAccountCentral.dtd
new file mode 100644
index 0000000000..a71c7252e5
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgAccountCentral.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY emailSectionHdr.label        "E-bost">
+<!ENTITY readMsgsLink.label           "Darllen negeseuon">
+<!ENTITY composeMsgLink.label         "Ysgrifennu neges newydd">
+
+<!ENTITY newsSectionHdr.label         "Grwpiau Newyddion">
+<!ENTITY subscribeNewsLink.label      "Rheoli tanysgrifiadau grwpiau newyddion">
+
+<!ENTITY feedsSectionHdr.label        "Llif">
+<!ENTITY subscribeFeeds.label         "Rheoli tanysgrifiadau">
+
+<!ENTITY chat.label                   "Sgwrs">
+<!ENTITY movemail.label               "Movemail">
+
+<!ENTITY accountsSectionHdr.label     "Cyfrifon">
+<!ENTITY subscribeImapFolders.label   "Rheoli tanysgrifiadau ffolderi">
+<!ENTITY settingsLink.label           "Edrych ar osodiadau'r cyfrif">
+<!ENTITY setupNewAcct.label           "Gosod cyfrif:">
+
+<!ENTITY advFeaturesSectionHdr.label  "Nodweddion Uwch">
+<!ENTITY searchMsgsLink.label         "Chwilio negeseuon">
+<!ENTITY filtersLink.label            "Rheoli hidlau negeseuon">
+<!ENTITY junkSettings.label           "Gosodiadau sbam">
+<!ENTITY offlineLink.label            "Gosodiadau all-lein">
diff --git a/l10n-cy/mail/chrome/messenger/msgHdrViewOverlay.dtd b/l10n-cy/mail/chrome/messenger/msgHdrViewOverlay.dtd
new file mode 100644
index 0000000000..824f70087d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgHdrViewOverlay.dtd
@@ -0,0 +1,114 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY toField4.label "At">
+<!ENTITY fromField4.label "Oddi wrth">
+<!ENTITY senderField4.label "Anfonwr">
+<!ENTITY author.label "Awdur">
+<!ENTITY organizationField4.label "Corff">
+<!ENTITY replyToField4.label "Ateb i">
+
+<!ENTITY subjectField4.label "Pwnc">
+<!ENTITY ccField4.label "Cc">
+<!ENTITY bccField4.label "Bcc">
+<!ENTITY newsgroupsField4.label "Grwpiau Newyddion">
+<!ENTITY followupToField4.label "Ymateb">
+<!ENTITY tagsHdr4.label "Tagiau">
+<!ENTITY dateField4.label "Dyddiad">
+<!ENTITY userAgentField4.label "Asiant defnyddiwr">
+<!ENTITY referencesField4.label "Cyfeiriadau">
+<!ENTITY messageIdField4.label "Enw Neges">
+<!ENTITY inReplyToField4.label "Wrth ateb i">
+<!ENTITY originalWebsite4.label "Gwefan">
+
+<!ENTITY hdrArchiveButton1.label "Archifo">
+<!ENTITY hdrArchiveButton1.tooltip "Archifo'r neges">
+<!ENTITY hdrSmartReplyButton1.label "Ateb Clyfar">
+<!ENTITY hdrReplyButton1.label "Ateb">
+<!ENTITY hdrReplyButton2.tooltip "Ateb i anfonwr y neges">
+<!ENTITY hdrReplyAllButton1.label "Ateb Pawb">
+<!ENTITY hdrReplyAllButton1.tooltip "Ateb yr anfonwr a phob derbyniwr">
+<!ENTITY hdrReplyListButton1.label "Ateb i'r Rhestr">
+<!ENTITY hdrReplyListButton1.tooltip "Ateb i'r rhestr e-bost">
+<!ENTITY hdrFollowupButton1.label "Dilyn">
+<!ENTITY hdrFollowupButton1.tooltip "Gosod cofnod dilynol i'r grŵp newyddion">
+<!ENTITY hdrForwardButton1.label "Ymlaen">
+<!ENTITY hdrForwardButton1.tooltip "Anfon y neges ymlaen">
+<!ENTITY hdrJunkButton1.label "Sbam">
+<!ENTITY hdrJunkButton1.tooltip "Nodi'r neges fel sbam">
+<!ENTITY hdrTrashButton1.label "Dileu">
+<!ENTITY hdrTrashButton1.tooltip "Dileu'r neges">
+
+<!ENTITY hdrViewToolbarShowFull.label "Dangos Eiconau a Thestun">
+<!ENTITY hdrViewToolbarShowFull.accesskey "E">
+<!ENTITY hdrViewToolbarShowIcons.label "Dangos Eiconau yn Unig">
+<!ENTITY hdrViewToolbarShowIcons.accesskey "U">
+<!ENTITY hdrViewToolbarShowText.label "Dangos Testun yn Unig">
+<!ENTITY hdrViewToolbarShowText.accesskey "U">
+<!ENTITY hdrViewToolbarAlwaysReplySender.label "Dangos Ateb i Anfonwr Bob Tro">
+<!ENTITY hdrViewToolbarAlwaysReplySender.accesskey "B">
+
+<!ENTITY otherActionsButton2.label "Rhagor">
+<!ENTITY otherActionsButton.tooltip "Rhagor o weithredoedd">
+<!ENTITY otherActionsOpenConversation1.label "Agor mewn Sgwrs">
+<!ENTITY otherActionsOpenConversation1.accesskey "S">
+<!ENTITY otherActionsOpenInNewWindow1.label "Agor Ffenestr Newydd">
+<!ENTITY otherActionsOpenInNewWindow1.accesskey "F">
+<!ENTITY otherActionsOpenInNewTab1.label "Agor mewn Tab Newydd">
+<!ENTITY otherActionsOpenInNewTab1.accesskey "T">
+<!ENTITY markAsReadMenuItem1.label "Marcio wedi Darllen">
+<!ENTITY markAsReadMenuItem1.accesskey "D">
+<!ENTITY markAsUnreadMenuItem1.label "Marcio heb Ddarllen">
+<!ENTITY markAsUnreadMenuItem1.accesskey "D">
+<!ENTITY saveAsMenuItem1.label "Cadw fel…">
+<!ENTITY saveAsMenuItem1.accesskey "C">
+<!ENTITY viewSourceMenuItem1.label "Gweld y Ffynhonell">
+<!ENTITY viewSourceMenuItem1.accesskey "F">
+<!ENTITY otherActionsPrint1.label "Argraffu…">
+<!ENTITY otherActionsPrint1.accesskey "A">
+
+<!-- Attachment bar context menu items -->
+<!ENTITY startExpandedCmd.label    "Dangos y Paen Atodiad yn Gyntaf">
+<!ENTITY startExpandedCmd.accesskey    "D">
+
+<!-- Attachment context menu items -->
+<!ENTITY openAttachmentCmd.label    "Agor">
+<!ENTITY openAttachmentCmd.accesskey    "o">
+<!ENTITY saveAsAttachmentCmd.label    "Cadw Fel…">
+<!ENTITY saveAsAttachmentCmd.accesskey    "C">
+<!ENTITY detachAttachmentCmd.label    "Datod…">
+<!ENTITY detachAttachmentCmd.accesskey    "D">
+<!ENTITY deleteAttachmentCmd.label    "Dileu">
+<!ENTITY deleteAttachmentCmd.accesskey    "l">
+<!ENTITY openAllAttachmentsCmd.label    "Agor Popeth…">
+<!ENTITY openAllAttachmentsCmd.accesskey    "A">
+<!ENTITY saveAllAttachmentsCmd.label    "Cadw Popeth…">
+<!ENTITY saveAllAttachmentsCmd.accesskey    "P">
+<!ENTITY detachAllAttachmentsCmd.label    "Datod Popeth…">
+<!ENTITY detachAllAttachmentsCmd.accesskey    "a">
+<!ENTITY deleteAllAttachmentsCmd.label    "Dileu Popeth…">
+<!ENTITY deleteAllAttachmentsCmd.accesskey    "i">
+
+<!ENTITY openAttachment.tooltip "Agor y ffeil atodol">
+
+<!ENTITY detachedAttachmentFolder.show.label        "Agor Ffolder Cynhwysol">
+<!ENTITY detachedAttachmentFolder.show.accesskey    "F">
+<!ENTITY detachedAttachmentFolder.showMac.label     "Dangos yn y Canfyddwr">
+<!ENTITY detachedAttachmentFolder.showMac.accesskey "C">
+
+<!-- Attachment toolbar items -->
+<!ENTITY saveAttachmentButton1.label       "Cadw">
+<!ENTITY saveAttachmentButton1.tooltip     "Cadw'r ffeil atodol">
+<!ENTITY saveAllAttachmentsButton1.label   "Cadw Pob Un">
+<!ENTITY saveAllAttachmentsButton1.tooltip "Cadw'r holl ffeiliau atodol">
+
+<!ENTITY copyLinkCmd.label        "Copïo Lleoliad Dolen">
+<!ENTITY copyLinkCmd.accesskey    "C">
+
+<!ENTITY CopyMessageId.label "Cadw Neges-Dynodiad">
+<!ENTITY CopyMessageId.accesskey "N">
+<!ENTITY OpenMessageForMsgId.label "Agor Neges ar gyfer Enw">
+<!ENTITY OpenMessageForMsgId.accesskey "A">
+<!ENTITY OpenBrowserWithMsgId.label "Agor Porwr gyda Neges-Dynodiad">
+<!ENTITY OpenBrowserWithMsgId.accesskey "P">
diff --git a/l10n-cy/mail/chrome/messenger/msgPrintEngine.dtd b/l10n-cy/mail/chrome/messenger/msgPrintEngine.dtd
new file mode 100644
index 0000000000..723d41a54a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgPrintEngine.dtd
@@ -0,0 +1,17 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE (printCmd.key, closeCmd.key):
+     As defined in msgPrintEngine.xul, Ctrl plus the command keys defined here
+     will be the keyboard shortcuts effective in print preview, e.g. Ctrl+P
+     -->
+
+
+<!-- LOCALIZATION NOTE (printCmd.key, closeCmd.key):
+     As defined in msgPrintEngine.xhtml, Ctrl plus the command keys defined here
+     will be the keyboard shortcuts effective in print preview, e.g. Ctrl+P
+     -->
+
+<!ENTITY printCmd.key "P">
+<!ENTITY closeCmd.key "W">
diff --git a/l10n-cy/mail/chrome/messenger/msgSynchronize.dtd b/l10n-cy/mail/chrome/messenger/msgSynchronize.dtd
new file mode 100644
index 0000000000..419fba268d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgSynchronize.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- extracted from MsgSynchronize.xul and msgSelectOffline.xul-->
+
+
+<!-- extracted from MsgSynchronize.xul and msgSelectOfflineFolders.xul-->
+
+<!-- extracted from MsgSynchronize.xhtml and msgSelectOfflineFolders.xhtml-->
+
+<!ENTITY MsgSynchronize.label "Llwytho i Lawr a Chydweddu Negeseuon">
+<!ENTITY MsgSelect.label "Eitemau ar Gyfer Defnydd All-lein">
+<!ENTITY MsgSyncDesc.label "Os ydych eisoes wedi dewis ffolderi e-bost neu grwpiau newyddion ar gyfer defnydd all-lein, mae modd i chi eu llwytho neu cydweddu nhw nawr. Yn lle hynny, defnyddiwch y botwm &quot;Dewis&quot; i ddewis ffolderi e-bost neu grwpiau newyddion ar gyfer defnydd all-lein.">
+<!ENTITY MsgSyncDirections.label "Llwytho i lawr a/neu gydweddu'r canlynol:">
+<!ENTITY syncTypeMail.label "Negeseuon e-bost">
+<!ENTITY syncTypeMail.accesskey "e">
+<!ENTITY syncTypeNews.label "Negeseuon grŵp newyddion">
+<!ENTITY syncTypeNews.accesskey "g">
+<!ENTITY sendMessage.label "Anfon negeseuon sydd heb eu Hanfon">
+<!ENTITY sendMessage.accesskey "A">
+<!ENTITY workOffline.label "Gweithio all-lein pan fydd y llwytho i lawr/cydweddiad wedi gorffen">
+<!ENTITY workOffline.accesskey "G">
+<!ENTITY selectButton.label "Dewis…">
+<!ENTITY selectButton.accesskey "e">
+<!ENTITY MsgSelectDesc.label "Dewiswch y ffolderi e-bost a grwpiau newyddion ar gyfer defnydd all-lein.">
+<!ENTITY MsgSelectInd.label "Llwytho i Lawr">
+<!ENTITY MsgSelectItems.label "Ffolderi a Grwpiau Newyddion">
diff --git a/l10n-cy/mail/chrome/messenger/msgViewPickerOverlay.dtd b/l10n-cy/mail/chrome/messenger/msgViewPickerOverlay.dtd
new file mode 100644
index 0000000000..17b1fb377c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgViewPickerOverlay.dtd
@@ -0,0 +1,23 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!--LOCALIZATION NOTE msgViewPickerOverlay.dtd UI for showing various views on a folder -->
+
+
+<!ENTITY viewPicker.label "Golwg:">
+<!ENTITY viewPicker.accesskey "l">
+<!ENTITY viewAll.label "Popeth">
+<!ENTITY viewAll.accesskey "P">
+<!ENTITY viewUnread.label "Heb eu Darllen">
+<!ENTITY viewUnread.accesskey "H">
+<!ENTITY viewNotDeleted.label "Heb ei Ddileu">
+<!ENTITY viewNotDeleted.accesskey "e">
+<!ENTITY viewTags.label "Tagiau">
+<!ENTITY viewTags.accesskey "T">
+<!ENTITY viewCustomViews.label "Golwg Cyfaddas">
+<!ENTITY viewCustomViews.accesskey "G">
+<!ENTITY viewVirtualFolder.label "Cadw Golwg fel Ffolder…">
+<!ENTITY viewVirtualFolder.accesskey "F">
+<!ENTITY viewCustomizeView.label "Cyfaddasu…">
+<!ENTITY viewCustomizeView.accesskey "C">
diff --git a/l10n-cy/mail/chrome/messenger/msgmdn.properties b/l10n-cy/mail/chrome/messenger/msgmdn.properties
new file mode 100644
index 0000000000..01b99ca3ea
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/msgmdn.properties
@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+## Msg Mdn Report strings
+MsgMdnDisplayed=Nodyn: Mae'r Dderbynneb Dychwelyd yn cydnabod bod y neges wedi ymddangos ar gyfrifiadur y derbynnydd. Nid oes gwarant fod y derbynnydd wedi darllen na deall cynnwys y neges.
+MsgMdnDispatched=Cafodd y neges ei hargraffu, ffacsio neu anfon ymlaen heb gael ei dangos i'r derbynnydd. Nid oes gwarant y bydd y derbynnydd yn darllen y neges yn diweddarach.
+MsgMdnProcessed=Cafodd y neges ei phrosesu gan raglen e-bost y derbynnydd heb ei dangos. Nid oes gwarant y bydd y derbynnydd yn darllen y neges yn ddiweddarach.
+MsgMdnDeleted=Mae'r neges wedi ei dileu. Ansicrwydd os yw'r derbynnydd wedi'i darllen neu beidio. Efallai byddant yn ei dad-dileu a'i darllen yn ddiweddarach rhywbryd.
+MsgMdnDenied=Nid yw derbynnydd y neges am anfon derbynneb derbyn yn ôl atoch chi.
+MsgMdnFailed=Digwyddodd gwall. Nid oedd modd creu nag anfon derbynneb dychwelyd dilys i chi.
+# LOCALIZATION NOTE : Do not translate the word "%S" below.
+MsgMdnMsgSentTo=Dyma Dderbynneb Dychwelyd am e-bost anfonwyd at %S.
+MdnDisplayedReceipt=Derbynneb Dychwelyd (dangos)
+MdnDispatchedReceipt=Derbynneb Dychwelyd (anfonwyd)
+MdnProcessedReceipt=Derbynneb Dychwelyd (prosesu)
+MdnDeletedReceipt=Derbynneb Dychwelyd (dileu)
+MdnDeniedReceipt=Derbynneb Dychwelyd (gwrthod)
+MdnFailedReceipt=Derbynneb Dychwelyd (methiant)
diff --git a/l10n-cy/mail/chrome/messenger/multimessageview.dtd b/l10n-cy/mail/chrome/messenger/multimessageview.dtd
new file mode 100644
index 0000000000..1e83dd68eb
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/multimessageview.dtd
@@ -0,0 +1,8 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title             "Crynodeb Neges">
+<!ENTITY selectedmessages.label   "Negeseuon wedi'u Dewis">
+<!ENTITY archiveButton.label      "Archifo">
+<!ENTITY deleteButton.label       "Dileu">
diff --git a/l10n-cy/mail/chrome/messenger/multimessageview.properties b/l10n-cy/mail/chrome/messenger/multimessageview.properties
new file mode 100644
index 0000000000..829b46a509
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/multimessageview.properties
@@ -0,0 +1,66 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (numConversations): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of conversations (threads or solitary messages) selected. #1 is the
+# number of conversations.
+numConversations=Dim trafodaethau; #1 trafodaeth; #1 drafodaeth; #1 trafodaeth; #1 thrafodaeth; #1 trafodaeth
+
+# LOCALIZATION NOTE (atLeastNumConversations): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of conversations (threads or solitary messages) selected. #1 is the
+# number of conversations. We use this when we didn't actually scan the entire
+# list of selected messages, so there may be more conversations than reported
+# (or maybe not!).
+atLeastNumConversations=Dim trafodaethau; #1+ trafodaeth; #1+ trafodaeth; #1+ trafodaeth; #1+ trafodaeth; #1+ trafodaeth
+
+# LOCALIZATION NOTE (numMessages): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of messages in a thread. #1 is the number of messages.
+numMessages=Dim negeseuon;#1 neges;#1 neges;#1 neges;#1 neges;#1 neges
+
+# LOCALIZATION NOTE (numUnread): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of unread messages in a thread; meant to be appended to
+# "numMessages". #1 is the number of unread messages.
+numUnread=, dim heb eu darllen;, #1 heb ei darllen;, #1 heb eu darllen;, #1 heb eu darllen;, #1 heb eu darllen;, #1 heb eu darllen
+
+# LOCALIZATION NOTE (numIgnored): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of ignored messages in a thread; meant to be appended to
+# "numMessages". #1 is the number of ignored messages.
+numIgnored=, Peidio anwybyddu;Anwybyddu #1;Anwybyddu #1;Anwybyddu #1;Anwybyddu #1;Anwybyddu #1
+
+# LOCALIZATION NOTE (atLeastNumIgnored): Semi-colon list of plural forms.
+# See: https://developer.mozilla.org/en/Localization_and_Plurals
+# The number of ignored messages in a thread; meant to be appended to
+# "numMessages". #1 is the number of ignored messages. We use this when we
+# didn't actually scan the entire list of selected messages, so there may be
+# more ignored messages than reported (or maybe not!).
+atLeastNumIgnored=, Peidio anwybyddu;, #1+ anwybyddwyd;, #1+ anwybyddwyd;, #1+ anwybyddwyd;, #1+ anwybyddwyd;, #1+ anwybyddwyd
+
+# LOCALIZATION NOTE (noSubject): What to display for a message if it has no
+# subject.
+noSubject=(dim pwnc)
+
+# LOCALIZATION NOTE (messagesTotalSize): A message indicating the total size on
+# disk of the selected messages. #1 is the size, e.g. "123 KB".
+messagesTotalSize=Mae'r negeseuon yn cymryd #1 o le.
+
+# LOCALIZATION NOTE (messagesTotalSizeMoreThan): A message indicating the total
+# size on disk of the selected messages. #1 is the size, e.g. "123 KB". We use
+# this when we didn't actually scan the entire list of selected messages, so
+# this is a *minimum* size.
+messagesTotalSizeMoreThan=Mae'r negeseuon yma'n cymryd mwy na #1 o le.
+
+# LOCALIZATION NOTE (maxCountExceeded): A message to let the user know that not
+# all of the selected messages were summarized. #1 is the total number of
+# messages selected and #2 is the number of messages actually shown.
+maxCountExceeded= (Sylwch: #1 neges wedi'u dewis, mae'r #2 cyntaf yn cael eu dangos)
+
+# LOCALIZATION NOTE (maxThreadCountExceeded): A message to let the user know that
+# not all of the selected thread were summarized. #1 is the total number of
+# threads selected and #2 is the number of threads actually shown.
+maxThreadCountExceeded= (Nodyn: #1 trywydd wedi'u dewis, #2 cyntaf yn cael eu dewis)
diff --git a/l10n-cy/mail/chrome/messenger/newFolderDialog.dtd b/l10n-cy/mail/chrome/messenger/newFolderDialog.dtd
new file mode 100644
index 0000000000..3686b6f68a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/newFolderDialog.dtd
@@ -0,0 +1,16 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- Labels -->
+   
+<!ENTITY newFolderDialog.title      "Ffolder Newydd">
+<!ENTITY name.label                 "Enw:">
+<!ENTITY name.accesskey             "E">
+<!ENTITY description.label          "Creu fel is-ffolder o:">
+<!ENTITY description.accesskey      "C">
+<!ENTITY folderRestriction1.label   "Mae'r gweinydd yn cyfyngu ffolderi i ddau fath arbennig.">
+<!ENTITY folderRestriction2.label   "Caniatáu eich ffolderi newydd i gynnwys:">
+<!ENTITY foldersOnly.label          "Ffolderi yn Unig">
+<!ENTITY messagesOnly.label         "Negeseuon yn Unig">
+<!ENTITY accept.label               "Creu Ffolder">
+<!ENTITY accept.accesskey           "r">
diff --git a/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.dtd b/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.dtd
new file mode 100644
index 0000000000..6e254a971e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.dtd
@@ -0,0 +1,43 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.title "Croeso i &brandShortName;">
+<!ENTITY header2.label "Hoffech chi gael cyfeiriad gwe newydd?">
+<!ENTITY other.languages "Dim ond y darparwyr sy'n cynnig cyfeiriadau yn eich ardal rydym yn eu dangos.  Cliciwch yma i ddangos yr holl ddarparwyr.">
+<!ENTITY error.line1 "Ymddiheuriadau, nid oeddem yn gallu canfod unrhyw un o'r cyfeiriadau e-bost awgrymwyd.">
+<!ENTITY error.line2 "Gallwch hefyd chwilio am lysenwau neu dermau eraill i ganfod ragor o e-byst eraill.">
+<!-- LOCALIZATION NOTE(error.suggest.before, error.suggest.middle, error.suggest.after):
+     error.suggest.before, error.suggest.middle, and error.suggest.after all go into
+     one line with error.suggest.middle that links to a site which provides download
+     of free account alternatives. -->
+
+<!ENTITY error.suggest.before "Gallwch hefyd brofi un o'r ">
+<!ENTITY error.suggest.middle "cyfrifon e-bost rhad ac am ddim eraill">
+<!ENTITY error.suggest.after ".">
+<!-- LOCALIZATION NOTE(success.title.before, success.title.after):
+     success.title.before and success.title.after all go into one line, wrapping
+     around the name that the user has typed in to the search input. -->
+
+<!ENTITY success.title.before "Helo ">
+<!ENTITY success.title.after ", mae'r cyfeiriadau e-bost canlynol ar gael ar eich cyfer:">
+<!ENTITY success.tip "(Gallwch hefyd chwilio am lysenwau neu dermau eraill i ganfod ragor o e-byst eraill)">
+<!ENTITY partnership.description "Mewn partneriaeth â nifer o ddarparwyr, mae &brandShortName; yn gallu cynnig cyfrif e-bost newydd i chi. Llenwch eich enw cyntaf ac olaf, neu unrhyw eiriau'r hoffech chi yn y meysydd uchod er mwyn cychwyn arni.">
+<!ENTITY existing.header "A oes gennych gyfrif cyfredol yr hoffech ei defnyddio?">
+<!ENTITY tinyheader.title "A oes gennych gyfeiriad?">
+<!ENTITY tinyheader.existing "Hepgor hwn a defnyddio fy e-bost cyfredol">
+<!ENTITY content.close "Mi wna i ffurfweddu fy nghyfrif yn diweddarach.">
+<!ENTITY successful.title "Llongyfarchiadau!">
+<!ENTITY successful.successMessage "Rydych wedi creu eich cyfrif yn llwyddiannus.">
+<!ENTITY successful.write "Ysgrifennu e-byst">
+<!ENTITY successful.write.desc "Gadewch i'ch ffrindiau â'ch teulu wybod am eich cyfrif newydd. <br/> Dyna pam rydych wedi agor y cyfrif newydd?">
+<!ENTITY successful.customize "Cyfaddaswch &brandShortName; gydag ychwanegion difyr">
+<!ENTITY successful.customize.desc "Mae yna filoedd o ychwanegion sy'n caniatáu i chi gyfaddasu &brandShortName; i'w wneud yn addas ar gyfer eich anghenion chi.">
+<!ENTITY successful.attach "Rhowch lofnod personol i'ch e-byst">
+<!ENTITY successful.attach.desc "Mae modd i chi atodi dyfyniad neu ryw wybodaeth amdanoch chi eich hun ar ddiwedd pob neges fyddwch yn ei hanfon.">
+<!ENTITY successful.close "Cau'r ffenestr.">
+<!ENTITY input.namePlaceholder "Eich enw neu lysenw">
+<!ENTITY input.search "Chwilio">
+<!ENTITY search_engine.title "Cyfaddasu eich peiriant chwilio">
+<!ENTITY search_engine.message "Gall eich darparwr e-bost ddarparu gallu chwilio gwe i chi.">
+<!ENTITY search_engine.button "Gorffen">
diff --git a/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.properties b/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.properties
new file mode 100644
index 0000000000..d531502fec
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/newmailaccount/accountProvisioner.properties
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (free):
+# This will be shown instead of a price when displaying free email accounts
+free=Rhydd
+# LOCALIZATION NOTE (price):
+#   %S will be the price per year charged to the user for the account.
+price=%S y flwyddyn
+# LOCALIZATION NOTE (moreOptions): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/Localization_and_Plurals
+# #1 is the number of additional email addresses available for registration.
+# This line is shown when there are more than two suggested email
+# addresses available.
+moreOptions=Dim yn rhagor…;+#1 rhagor…;+#1 rhagor…;+#1 rhagor…;+#1 rhagor…;+#1 rhagor…
+# LOCALIZATION NOTE (sepAnd):
+#   \u0020 is a space, and should be included before and after.
+sepAnd=\u0020a\u0020
+# LOCALIZATION NOTE (sepComma):
+#   \u0020 is a space, and should be included after.
+sepComma=,\u0020
+privacyDisclaimer=Mae'r geiriau chwilio yn cael eu hanfon at Mozilla (#1) ac i ddarparwyr e-bost trydydd parti #2 i ganfod cyfeiriadau e-bost.
+privacyPolicy=Polisi Preifatrwydd
+tos=Amodau Gwasanaeth
+searchEngineDesc=Defnyddio %S fel fy mheiriant chwilio ragosodedig
+cannotConnect=Ymddiheuriadau - nid ydym yn gallu cyfathrebu gydag ein gweinydd cofrestru. Gwiriwch eich cysylltiad.
diff --git a/l10n-cy/mail/chrome/messenger/news.properties b/l10n-cy/mail/chrome/messenger/news.properties
new file mode 100644
index 0000000000..6d3f1227c2
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/news.properties
@@ -0,0 +1,56 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+downloadHeadersTitlePrefix=Llwytho Penynnau i Lawr
+downloadHeadersInfoText=Mae yna %S pennawd neges newydd i'w llwytho i lawr ar gyfer y grŵp newyddion yma.
+cancelDisallowed=Nid yw'r neges yn ymddangos ei fod yn dod oddi wrthych chi.  Mae modd i chi ddiddymu eich cofnodion eich hun yn unig, nid rhai wnaed gan eraill.
+cancelConfirm=Ydych chi'n siŵr eich bod am ddiddymu'r neges?
+messageCancelled=Diddymwyd y neges.
+enterUserPassTitle=Mae Angen Enw Defnyddiwr a Chyfrinair Gweinydd Newyddion
+# LOCALIZATION NOTE (enterUserPassServer): %S is the server being accessed
+enterUserPassServer=Rhowch enw defnyddiwr a chyfrinair ar gyfer: %S:
+# LOCALIZATION NOTE (enterUserPassGroup): %1$S is a specific newsgroup to set
+# the password for; %2$S is the server from which the newsgroup is accessed
+enterUserPassGroup=Rhowch enw defnyddiwr a chyfrinair ar gyfer %1$S ar %2$S:
+okButtonText=Llwytho i Lawr
+
+noNewMessages=Does dim negeseuon newydd ar y gweinydd.
+# LOCALIZATION NOTE (newNewsgroupHeaders): %1$S is the number of the current
+# header being downloaded, %2$S is the number of headers to be downloaded, and
+#  %3$S is the newsgroup whose headers are being downloaded.
+newNewsgroupHeaders=Yn llwytho i lawr %1$S o benawdau %2$S ar gyfer %3$S
+# LOCALIZATION NOTE (newNewsgroupFilteringHeaders): %1$S is the name of the MIME
+# header being filtered on, %2$S is the number of the current header being
+# downloaded, %3$S is the number of headers to be downloaded, and %4$S is the
+# newsgroup whose headers are being downloaded.
+newNewsgroupFilteringHeaders=Estyn penynnau ar gyfer hidlau: %1$S (%2$S/%3$S) ar %4$S
+downloadingArticles=Yn llwytho erthyglau %S-%S i lawr
+bytesReceived=Llwytho Grwpiau Newyddion: %S derbyniwyd (darllen %SKB ar %SKB/eil)
+downloadingArticlesForOffline=Yn llwytho erthyglau %S-%S i lawr yn %S
+
+# LOCALIZATION NOTE (autoUnsubscribeText): %1$S is the newsgroup and %2$S is the newsgroup-server it is being removed from.
+autoUnsubscribeText=Nid yw'n ymddangos fod grŵp newyddion %1$S yn bodoli ar y gwestai %2$S.  Hoffech chi ddad-danysgrifio?
+
+# LOCALIZATION NOTE (autoSubscribeText): %1$S is the newsgroup.
+autoSubscribeText=Hoffech chi danysgrifio i %1$S?
+
+# LOCALIZATION NOTE (Error -304): In the following item, don't translate "NNTP"
+# Error - server error
+## @name NNTP_ERROR_MESSAGE
+## @loc None
+-304=Digwyddodd gwall Newyddion (NNTP): \u0020
+
+# Error - newsgroup scan error
+## @name NNTP_NEWSGROUP_SCAN_ERROR
+## @loc None
+-305=Digwyddodd gwall Newyddion.  Mae'r archwiliad o'r holl grwpiau newyddion yn anghyflawn.  Ceisiwch Edrych ar yr Holl Grwpiau newyddion eto
+
+# Error - NNTP authinfo failure
+## @name NNTP_AUTH_FAILED
+## @loc None
+-260=Digwyddodd gwall caniatâd.  Ceisiwch gynnig eich enw a/neu eich cyfrinair eto.
+
+# Error - TCP error
+## @name TCP_ERROR
+## @loc None
+-206=Digwyddodd gwall cyfathrebu.  Ceisiwch gysylltu eto.  Gwall TCP:
diff --git a/l10n-cy/mail/chrome/messenger/newsError.dtd b/l10n-cy/mail/chrome/messenger/newsError.dtd
new file mode 100644
index 0000000000..562dc2e297
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/newsError.dtd
@@ -0,0 +1,31 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (newsError.title): The title of the news error page.
+     Not generally visible. -->
+
+<!ENTITY newsError.title "Anhawster Llwytho Erthygl">
+<!-- LOCALIZATION NOTE (articleNotFound.title): The main heading for the news
+     error page. -->
+
+<!ENTITY articleNotFound.title "Heb ganfod erthygl">
+<!-- LOCALIZATION NOTE (articleNotFound.desc): A longer description for the news
+     error page. -->
+
+<!ENTITY articleNotFound.desc "Mae y grwp gweinydd newyddion yn adrodd nad yw'n gallu canfod yr erthygl.">
+<!-- LOCALIZATION NOTE (serverResponded.title): A string preceding the text
+     response from the newsgroup server describing the error. -->
+
+<!ENTITY serverResponded.title "Ymateb gweinydd y grwp newyddion yw:">
+<!-- LOCALIZATION NOTE (articleExpired.title): A string explaining that the
+     article may have expired. -->
+
+<!ENTITY articleExpired.title "Efallai fod yr erthygl wedi dod i ben?">
+<!-- LOCALIZATION NOTE (trySearching.title): A string preceding the message's
+     ID. -->
+
+<!ENTITY trySearching.title "Ceisio chwilio am yr erthygl:">
+<!-- LOCALIZATION NOTE (removeExpiredArticles.title): The label for the button
+     to remove all expired articles from the newsgroup. -->
+
+<!ENTITY removeExpiredArticles.title "Tynnu'r Holl Erthyglau sydd wedi dod i Ben">
diff --git a/l10n-cy/mail/chrome/messenger/oeImportMsgs.properties b/l10n-cy/mail/chrome/messenger/oeImportMsgs.properties
new file mode 100644
index 0000000000..d7e90f09e1
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/oeImportMsgs.properties
@@ -0,0 +1,81 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the outlook express import code to display status/error 
+# and informational messages
+#
+
+#
+# The following are used by the outlook express import code to display status/error
+# and informational messages
+#
+
+# Short name of import module
+## @name OEIMPORT_NAME
+## @loc None
+## LOCALIZATION NOTE (2000): DONT_TRANSLATE
+2000=Outlook Express
+
+# Description of import module
+## @name OEIMPORT_DESCRIPTION
+## @loc None
+## LOCALIZATION NOTE (2011): In this item, don't translate "Outlook Express"
+2011=E-bost a llyfrau cyfeiriadau Outlook Express
+
+# Success message
+## @name OEIMPORT_MAILBOX_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2002): In this item, don't translate "%S" or "%d"
+## The variable %S will contain the name of the Mailbox
+## The variable %d will contain the number of messages
+2002=Blwch e-bost %S, mewnforiwyd %d neges
+
+# Error message
+## @name OEIMPORT_MAILBOX_BADPARAM
+## @loc None
+2003=Paramedr gwallus wedi'i basio i flwch e-bost mewnforio.
+
+# Error message
+## @name OEIMPORT_MAILBOX_BADSOURCEFILE
+## @loc None
+## LOCALIZATION NOTE (2004): In this item, don't translate "%S"
+## The variable %S will contain the name of the Mailbox
+2004=Gwall wrth gael mynediad i flwch e-bost %S.
+
+# Error message
+## @name OEIMPORT_MAILBOX_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2005): In this item, don't translate "%S"
+## The variable %S will contain the name of the Mailbox
+2005=Gwall wrth fewnforio blwch e-bost %S, efallai na fydd yr holl negeseuon yn cael eu mewnforio o'r blwch e-bost.
+
+# Default name of imported addressbook
+## @name OEIMPORT_DEFAULT_NAME
+## @loc None
+2006=Llyfr Cyfeiriadau Outlook Express
+
+# Autofind description
+## @name OEIMPORT_AUTOFIND
+## @loc None
+2007=Llyfr cyfeiriadau Outlook Express (llyfr cyfeiriadau windows)
+
+# Description
+## @name OEIMPORT_ADDRESS_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2006): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2008=Mewnforiwyd llyfr cyfeiriadau %S
+
+# Error message
+## @name OEIMPORT_ADDRESS_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2009): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2009=Gwall wrth fewnforio llyfr cyfeiriadau %S, efallai nad yw'r holl gyfeiriadau wedi'u mewnforio.
+
+# Error message
+## @name OEIMPORT_ADDRESS_BADPARAM
+## @loc None
+2010=Pasiwyd paramedrau gwallus i'r llyfr cyfeiriadau sydd wedi'i fewnforio.
diff --git a/l10n-cy/mail/chrome/messenger/offline.properties b/l10n-cy/mail/chrome/messenger/offline.properties
new file mode 100644
index 0000000000..e0a35839ba
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/offline.properties
@@ -0,0 +1,28 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Download Messages Prompt
+downloadMessagesWindowTitle1=Llwytho Negeseuon i Lawr
+downloadMessagesLabel1=Hoffech chi lwytho negeseuon i lawr ar gyfer defnydd all-lein cyn mynd all-lein?
+downloadMessagesCheckboxLabel1=Gofyn pob tro fyddaf yn mynd all-lein
+downloadMessagesNow2=&Llwytho i Lawr Nawr
+
+# Send Messages Prompt
+sendMessagesWindowTitle1=Negeseuon heb eu Hanfon
+sendMessagesLabel2=Hoffech chi anfon y negeseuon sydd heb eu hanfon?
+sendMessagesCheckboxLabel1=Gofyn pob tro cyn i mi fynd ar-lein
+sendMessagesNow2=&Anfon Nawr
+
+processMessagesLater2=&Hwyrach
+
+# GetMessages While Offline Prompt
+getMessagesOfflineWindowTitle1=Estyn Negeseuon
+getMessagesOfflineLabel1=Rydych all-lein. Hoffech chi fynd ar-lein i estyn negeseuon newydd?
+
+# Send Messages Offline Prompt
+sendMessagesOfflineWindowTitle1=Negeseuon heb eu Hanfon
+sendMessagesOfflineLabel1=Rydych all-lein ar hyn o bryd. Hoffech chi fynd ar-lein ac anfon negeseuon sydd heb eu hanfon?
+
+offlineTooltip=Rydych all-lein.
+onlineTooltip=Rydych ar-lein.
diff --git a/l10n-cy/mail/chrome/messenger/offlineStartup.properties b/l10n-cy/mail/chrome/messenger/offlineStartup.properties
new file mode 100644
index 0000000000..ca05774262
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/offlineStartup.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+title=Gweithio Ar-lein
+desc=Hoffech chi fynd ar-lein?\n\n(Os hoffech weithio all-lein, mae'n bosib mynd ar-lein yn ddiweddarach -dewiswch 'All-lein' o'r ddewislen 'Ffeil', yna dad -dicio 'Gweithio All-lein'.)
+workOnline=Gweithio Ar-lein
+workOffline=Gweithio All-lein
diff --git a/l10n-cy/mail/chrome/messenger/outlookImportMsgs.properties b/l10n-cy/mail/chrome/messenger/outlookImportMsgs.properties
new file mode 100644
index 0000000000..98ce8ca59e
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/outlookImportMsgs.properties
@@ -0,0 +1,77 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the outlook express import code to display status/error 
+# and informational messages
+#
+
+#
+# The following are used by the outlook express import code to display status/error
+# and informational messages
+#
+
+# Short name of import module
+## @name OUTLOOKIMPORT_NAME
+## @loc None
+## LOCALIZATION NOTE (2000): DONT_TRANSLATE
+2000=Outlook
+
+# Description of import module
+## @name OUTLOOKIMPORT_DESCRIPTION
+## @loc None
+## LOCALIZATION NOTE (2010): In this item, don't translate "Outlook"
+2010=E-bost a llyfrau cyfeiriadau Outlook
+
+# Success message
+## @name OUTLOOKIMPORT_MAILBOX_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2002): In this item, don't translate "%S" or "%d"
+## The variable %S will receive the name of the mailbox
+## The variable %d will receive the number of messages
+2002=Blwch e-bost %S, mewnforiwyd %d neges
+
+# Error message
+## @name OUTLOOKIMPORT_MAILBOX_BADPARAM
+## @loc None
+2003=Paramedr gwallus wedi'i basio i flwch e-bost mewnforio.
+
+# Error message
+## @name OUTLOOKIMPORT_MAILBOX_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2004): In this item, don't translate "%S"
+## The variable %S will receive the name of the mailbox
+2004=Gwall wrth fewnforio blwch e-bost %S, efallai na fydd yr holl negeseuon yn cael eu mewnforio o'r blwch e-bost.
+
+# Address book name
+## @name OUTLOOKIMPORT_ADDRNAME
+## @loc None
+## LOCALIZATION NOTE (2005): In this item, don't translate "Outlook"
+2005=Llyfrau cyfeiriadau Outlook
+
+# Description
+## @name OUTLOOKIMPORT_ADDRESS_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2006): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2006=Mewnforiwyd llyfr cyfeiriadau %S
+
+# Error message
+## @name OUTLOOKIMPORT_ADDRESS_BADPARAM
+## @loc None
+2007=Trosglwyddwyd paramedrau gwallus i'r llyfr cyfeiriadau mewnforio.
+
+# Error message
+## @name OUTLOOKIMPORT_ADDRESS_BADSOURCEFILE
+## @loc None
+## LOCALIZATION NOTE (2008): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2008=Gwall wrth gael mynediad ar gyfer llyfr cyfeiriadau %S.
+
+# Error message
+## @name OUTLOOKIMPORT_ADDRESS_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2009): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2009=Gwall wrth fewnforio llyfr cyfeiriadau %S, efallai nad yw'r holl gyfeiriadau wedi'u mewnforio.
diff --git a/l10n-cy/mail/chrome/messenger/pgpmime.properties b/l10n-cy/mail/chrome/messenger/pgpmime.properties
new file mode 100644
index 0000000000..e60b6a0d15
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/pgpmime.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the pgpmime content type handler
+#
+
+# LOCALIZATION NOTE(pgpMimeNeedsAddon): The text can contain HTML tags.
+pgpNotAvailable=Neges OpenPGP wedi'i hamgryptio yw hon, ond nid oes cefnogaeth ar gyfer dadgryptio OpenPGP ar gael.
diff --git a/l10n-cy/mail/chrome/messenger/preferences/applicationManager.properties b/l10n-cy/mail/chrome/messenger/preferences/applicationManager.properties
new file mode 100644
index 0000000000..4f566cf64b
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/preferences/applicationManager.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE
+# in descriptionApplications, %S will be replaced by one of the 3 following strings
+descriptionApplications=Mae modd defnyddio'r rhaglenni canlynol i drin %S.
+
+handleProtocol=%S dolen
+handleFile=Cynnwys %S
+
+descriptionWebApp=Mae'r rhaglen gwe yma wedi'i gweini yn:
+descriptionLocalApp=Mae'r rhaglen wedi'i lleoli yn:
diff --git a/l10n-cy/mail/chrome/messenger/preferences/applications.properties b/l10n-cy/mail/chrome/messenger/preferences/applications.properties
new file mode 100644
index 0000000000..ff84d06f03
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/preferences/applications.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (dialog_removeAccount):
+# %S will be replaced with the user-defined name of a storage account.
+dialog_removeAccount=Ydych chi'n siŵr eich bod am ddiddymu'r cyfrif "%S"?
+
+# LOCALIZATION NOTE (addProvider):
+# %S will be replace with the display name of a provider, e.g. DropBox
+addProvider=Ychwanegu %S
+
+notConfiguredYet=Nid yw'r cyfrif hwn wedi'i ffurfweddu eto
diff --git a/l10n-cy/mail/chrome/messenger/preferences/messagestyle.properties b/l10n-cy/mail/chrome/messenger/preferences/messagestyle.properties
new file mode 100644
index 0000000000..16460e1b1a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/preferences/messagestyle.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Content of preview conversation for chat message styles
+default=Rhagosodedig
+nick1=Florian
+buddy1=florian@im.instantbird.org
+nick2=Patrick
+buddy2=patrick@im.instantbird.org
+message1=Helo! :-)
+message2=Be sy'n digwydd?
+message3=Rwy'n profi Thunderbird! ;-)
diff --git a/l10n-cy/mail/chrome/messenger/preferences/preferences.properties b/l10n-cy/mail/chrome/messenger/preferences/preferences.properties
new file mode 100644
index 0000000000..23244ebc32
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/preferences/preferences.properties
@@ -0,0 +1,118 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#### Add HTML and Plain Text Domain Names for sendOption
+html_domainsAddDomainTitle=Ychwanegu Enw Parth HTML
+html_domainsAddDomain=Enw Parth HTML:
+plaintext_domainsAddDomainTitle=Ychwanegu Enw Parth Testun Plaen
+plaintext_domainsAddDomain=Enw Parth Testun Plaen:
+
+domainNameErrorTitle=Gwall Enw Parth
+#### LOCALIZATION NOTE: do not translate %S
+domainDuplicationError=Mae'r enw parth %S eisioes yn bodoli mewn rhestrau HTML neu Destun Plaen.
+
+#### Junk
+confirmResetJunkTrainingTitle=Cadarnhau
+confirmResetJunkTrainingText=Ydych chi'n siŵr eich bod eisiau ailosod data hyfforddi'r hidl addasol?
+
+#### Downloads
+desktopFolderName=Bwrdd Gwaith
+myDownloadsFolderName=Fy Llwythi
+chooseAttachmentsFolderTitle=Dewis Ffolder
+
+#### Applications
+
+fileEnding=Ffeil %S
+saveFile=Cadw Ffeil
+
+# LOCALIZATION NOTE (useApp, useDefault): %S = Application name
+useApp=Defnyddio %S
+useDefault=Defnyddio %S (rhagosodiad)
+
+useOtherApp=Defnyddio arall…
+fpTitleChooseApp=Dewis Rhaglen Gynorthwyol
+manageApp=Manylion y Rhaglen…
+alwaysAsk=Gofyn bob tro
+delete=Gweithred Dileu
+confirmDeleteTitle=Gweithred Dileu
+confirmDeleteText=Ydych chi'n siŵr eich bod eisiau dileu'r weithred?
+
+# LOCALIZATION NOTE (typeDescriptionWithDetails):
+# %1$S = type description (for example "Portable Document Format")
+# %2$S = details (see below, for example "(application/pdf: .pdf, .pdfx)")
+typeDescriptionWithDetails=%1$S %2$S
+
+# LOCALIZATION NOTE (typeDetailsWithTypeOrExt):
+# %1$S = type or extensions (for example "application/pdf", or ".pdf, .pdfx")
+typeDetailsWithTypeOrExt=(%1$S)
+
+# LOCALIZATION NOTE (typeDetailsWithTypeAndExt):
+# %1$S = type (for example "application/pdf")
+# %2$S = extensions (for example ".pdf, .pdfx")
+typeDetailsWithTypeAndExt=(%1$S: %2$S)
+
+#### Sound Notifications
+soundFilePickerTitle=Dewis Sain
+
+#### Search Engine Picker
+searchEnginePickerTitle=Dewiswch Beiriant Chwilio
+searchEngineType2=Peiriannau Chwilio
+
+#### Remote content
+imagepermissionstext=Mae modd i chi bennu pa ddelweddau gwefannau a chynnwys pell eraill sy'n cael caniatâd i'w llwytho. Mae hefyd modd i chi ganiatáu'r holl gynnwys pell yn seiliedig ar gyfeiriad e-bost yr anfonwr. Teipiwch gyfeiriad y wefan neu e-bost rydych am ei rheoli ac yna chlicio Rhwystro neu Caniatáu.
+imagepermissionstitle=Eithriadau - Cynnwys Pell
+
+#### Cookies
+cookiepermissionstitle=Eithriadau - Cwcis
+cookiepermissionstext=Gallwch nodi pa wefannau sy'n cael defnyddio cwcis.  Teipiwch union gyfeiriad y wefan rydych am ei ganiatáu ac yna cliciwch Rhwystro, Caniatáu am y Sesiwn neu Caniatáu.
+
+#### Cookie Viewer
+hostColon=Gwesteiwr:
+domainColon=Parth:
+forSecureOnly=Cysylltiadau wedi'u hamgryptio'n unig
+forAnyConnection=Unrhyw fath o gysylltiad
+expireAtEndOfSession=Ar ddiwedd sesiwn
+
+noCookieSelected=<heb ddewis cwci>
+cookiesAll=Mae'r cwcis canlynol wedi'u storio ar eich cyfrifiadur:
+cookiesFiltered=Mae'r cwcis canlynol yn cyd-fynd â'r chwilio:
+# LOCALIZATION NOTE (removeSelectedCookies):
+# Semicolon-separated list of plural forms. See:
+# https://developer.mozilla.org/en/docs/Localization_and_Plurals
+# If you need to display the number of selected elements in your language,
+# you can use #1 in your localization as a placeholder for the number.
+# For example this is the English string with numbers:
+# removeSelectedCookies=Remove #1 Selected;Remove #1 Selected
+removeSelectedCookies=Peidio tynnu'r dewisiadau;Tynnu'r dewis;Tynnu'r dewis;Tynnu'r dewis;Tynnu'r dewis;Tynnu'r dewis
+defaultUserContextLabel=Dim
+
+####Preferences::Advanced::Network
+#LOCALIZATION NOTE: The next string is for the disk usage of the cache.
+#   e.g., "Your cache is currently using 200 MB"
+#   %1$S = size
+#   %2$S = unit (MB, KB, etc.)
+actualDiskCacheSize=Mae eich storfa yn defnyddio %1$S %2$S o le ar ddisg
+actualDiskCacheSizeCalculated=Cyfrifo maint y storfa…
+
+# LOCALIZATION NOTE (labelDefaultFont): %S = font name
+labelDefaultFont=Rhagosodiad (%S)
+labelDefaultFontUnnamed=Rhagosodiad
+
+# LOCALIZATION NOTE (appLocale.label): %S = Name of the application locale,
+# e.g. English (United States)
+appLocale.label=Locale rhaglen: %S
+appLocale.accesskey=r
+# LOCALIZATION NOTE (rsLocale.label): %S = Name of the locale chosen in regional settings,
+# e.g. German (Germany)
+rsLocale.label=Gosodiadau rhanbarthol locale: %S
+rsLocale.accesskey=r
+
+#### Master Password (Moved to Fluent in M-C in bug 1435915)
+pw_change2empty_in_fips_mode=Ar hyn o bryd rydych yn y modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+pw_change_failed_title=Methodd Newid eich Cyfrinair
+
+applications-type-pdf = Portable Document Format (PDF)
+
+# LOCALIZATION NOTE (previewInApp): %S = brandShortName
+previewInApp=Rhagolwg yn %S
diff --git a/l10n-cy/mail/chrome/messenger/prefs.properties b/l10n-cy/mail/chrome/messenger/prefs.properties
new file mode 100644
index 0000000000..af2482f569
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/prefs.properties
@@ -0,0 +1,90 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The following are used by the Account Wizard
+#
+enterValidEmail=Rhowch gyfeiriad e-bost dilys.
+accountNameExists=Mae cyfrif gyda'r enw hwnnw'n bodoli eisoes. Rhowch enw arall arno.
+accountNameEmpty=Nid oes modd i enw'r cyfrif fod yn wag.
+modifiedAccountExists=Mae cyfrif gyda'r enw defnyddiwr ac enw gweinydd hynny'n bodoli eisoes. Rhowch enw defnyddiwr a/neu enw gweinydd gwahanol.
+userNameChanged=Mae eich Enw Defnyddiwr wedi'i ddiweddaru. Mae'n bosibl bod angen i chi ddiweddaru'r Cyfeiriad E-bost a/neu Enw Defnyddiwr sy'n gysylltiedig.
+serverNameChanged=Mae gosodiadau enw'r gweinydd wedi newid. Gwiriwch fod unrhyw ffolderi sy'n cael eu defnyddio gan hidlau'n bodoli ar y gweinydd newydd.
+# LOCALIZATION NOTE (junkSettingsBroken): %1$S is the account name
+junkSettingsBroken=O bosib mae gan osodiadau sbam ar gyfrif "%1$S" anhawster. Hoffech chi eu hadolygu cyn cadw Gosodiadau Cyfrif?
+# LOCALIZATION NOTE (localDirectoryChanged): %1$S is program name (&brandShortName;)
+localDirectoryChanged=Mae %1$S angen ailgychwyn er mwyn gosod y newidiadau i osodiadau'r cyfeiriadur Lleol.
+localDirectoryRestart=Ailgychwyn
+userNameEmpty=Nid oes modd i'r enw defnyddiwr fod yn wag.
+# LOCALIZATION NOTE (localDirectoryInvalid): %1$S is path to folder
+localDirectoryInvalid=Mae'r llwybr Cyfeiriadur Lleol "%1$S" yn annilys. Dewiswch gyfeiriadur arall.
+# LOCALIZATION NOTE (localDirectoryNotAllowed): %1$S is path to folder
+localDirectoryNotAllowed=Nid yw llwybr Cyfeiriadur Lleol "%1$S" yn addas ar gyfer storio negeseuon. Dewiswch gyfeiriadur arall.
+# if the user chooses to cancel the wizard when no accounts are there throw a message
+# LOCALIZATION NOTE (cancelWizard)
+# do not localize "\n\n"
+cancelWizard=Ydych chi'n siŵr eich bod am adael y Dewin Cyfrif?\n\n Os ydych yn gadael bydd unrhyw wybodaeth rydych wedi'i gynnig yn cael ei golli ac ni fydd y cyfrif yn cael ei greu.
+accountWizard=Dewin Cyfrif
+WizardExit=Gadael
+WizardContinue=Diddymu
+# when the wizard already has a domain (Should we say something different?)
+enterValidServerName=Rhowch enw gweinydd dilys.
+failedRemoveAccount=Methu dileu'r cyfrif.
+#LOCALIZATION NOTE: accountName: %1$S is server name, %2$S is user name
+accountName=%1$S - %2$S
+
+# LOCALIZATION NOTE: confirmDeferAccountWarning: do not localize "\n\n", it means a new empty line in the string.
+confirmDeferAccountWarning=Os ydych yn cadw e-bost newydd y cyfrif mewn Blwch Derbyn cyfrif gwahanol, ni fydd modd i chi gael mynediad at e-byst y cyfrif hwn sydd eisoes wedi eu llwytho i lawr. Os oes gennych e-byst yn y cyfrif hwn, copïwch nhw i gyfrif arall yn gyntaf.\n\nOs oes gennych hidlau sy'n hidlo e-bost i'r cyfrif hwn, dylech eu hanalluogi neu newid y ffolder targed. Os oes gan unrhyw gyfrif ffolderi arbennig yn y cyfrif hwn (Anfonwyd, Drafftiau, Templedi, Archifau, Sbam) dylech eu newid i gyfrif arall.\n\n A ydych dal eisiau cadw e-bost y cyfrif mewn cyfrif gwahanol?
+confirmDeferAccountTitle=Gohirio'r Cyfrif?
+
+directoryAlreadyUsedByOtherAccount=Mae cyfeiriadur rhiant y cyfeiriadur pennwyd yn y gosodiad Cyfeiriadur Lleol eisoes yn cael ei ddefnyddio gan y cyfrif "%S". Dewiswch gyfeiriadur arall.
+directoryParentUsedByOtherAccount=Mae cyfeiriadur rhiant y cyfeiriadur pennwyd yn y gosodiad Cyfeiriadur Lleol eisoes yn cael ei ddefnyddio gan y cyfrif "%S". Dewiswch gyfeiriadur arall.
+directoryChildUsedByOtherAccount=Mae is-gyfeiriadur y cyfeiriadur pennwyd yn y gosodiad Cyfeiriadur Lleol eisoes yn cael ei ddefnyddio gan y cyfrif "%S". Dewiswch gyfeiriadur arall.
+#Provide default example values for sample email address
+exampleEmailUserName=defnyddiwr
+exampleEmailDomain=esiampl.net
+emailFieldText=Cyfeiriad E-bost:
+#LOCALIZATION NOTE: defaultEmailText: %1$S is user name, %2$S is domain
+defaultEmailText=Rhowch eich cyfeiriad e-bost. Hwn fydd y cyfeiriad bydd eraill yn anfon e-bost atoch (e.e, "%1$S@%2$S").\u0020
+#LOCALIZATION NOTE: customizedEmailText: %1$S is provider, %2$S is email username, %3$S is sample email, %4$S is sample username
+customizedEmailText=Rhowch eich %1$S%2$S (er enghraifft, os mai "%3$S" yw eich cyfrif e-bost %1$S, yna %2$S yw eich "%4$S").\u0020
+
+# account manager stuff
+prefPanel-server=Gosodiadau'r Gweinydd
+prefPanel-copies=Copïau a Ffolderi
+prefPanel-synchronization=Cydweddu a Storio
+prefPanel-diskspace=Lle ar Ddisg
+prefPanel-addressing=Ysgrifennu a Chyfeirio
+prefPanel-junk=Gosodiadau Sbam
+## LOCALIZATION NOTE (prefPanel-smtp): Don't translate "SMTP"
+prefPanel-smtp=Gweinydd Anfon (SMTP)
+
+# account manager multiple identity support
+#LOCALIZATION NOTE: accountName: %1$S
+identity-list-title=Enwau ar gyfer %1$S
+
+identityDialogTitleAdd=Hunaniaeth Newydd
+## LOCALIZATION NOTE (identityDialogTitleEdit): %S is the identity name
+identityDialogTitleEdit=Golygu %S
+
+identity-edit-req=Rhaid enwi cyfeiriad e-bost dilys ar gyfer yr enw hwn.
+identity-edit-req-title=Gwall wrth Greu Enw
+
+## LOCALIZATION NOTE (identity-delete-confirm): %S is the identity name
+# and should be put on a new line. The new line is produced with the "\n" string.
+identity-delete-confirm=Ydych chi'n siŵr eich bod eisiau dileu'r hunaniaeth\n%S?
+## LOCALIZATION NOTE (identity-delete-confirm-title): %S is the account name
+identity-delete-confirm-title=Dileu hunaniaeth %S
+identity-delete-confirm-button=Dileu
+
+choosefile=Dewis ffeil
+
+forAccount=Ar gyfer cyfrif "%S"
+
+removeFromServerTitle=Cadarnhau dileu negeseuon yn awtomatig, yn barhaol
+removeFromServer=Bydd y gosodiad hwn yn dileu yn barhaol hen negeseuon o weinydd pell A'CH storfa leol. Ydych chi'n siŵr eich bod am barhau?
+
+confirmSyncChangesTitle=Cadarnhau newidiadau cydweddu
+confirmSyncChanges=Mae gosodiadau Cydweddu Neges wedi eu newid.\n\nHoffech chi eu cadw?
+confirmSyncChangesDiscard=Dileu
+
diff --git a/l10n-cy/mail/chrome/messenger/quickFilterBar.dtd b/l10n-cy/mail/chrome/messenger/quickFilterBar.dtd
new file mode 100644
index 0000000000..c7a8a55189
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/quickFilterBar.dtd
@@ -0,0 +1,276 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE (quickFilterBar.qfbShowFilterBar.label):
+     The label  for the button on the tab bar that toggles the visibility of
+     the quick filter bar.
+     -->
+<!ENTITY quickFilterBar.qfbShowFilterBar.label
+         "Hidl Cyflym">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.toggleBarVisibility.menu.label):
+     The label to display for the "View... Toolbars..." menu item that controls
+     whether the quick filter bar is visible.
+     -->
+<!ENTITY quickFilterBar.toggleBarVisibility.menu.label
+         "Bar Hidlo Cyflym">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.toggleBarVisibility.menu.accesskey):
+     The access key for the "View... Toolbars..." menu item label that controls
+     whether the quick filter bar is visible.
+     -->
+<!ENTITY quickFilterBar.toggleBarVisibility.menu.accesskey
+         "H">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.toggleBarVisibility.appmenu.label):
+     The label to display for the "App Menu... Preferences..." menu item that
+     controls whether the quick filter bar is visible.
+     -->
+<!ENTITY quickFilterBar.toggleBarVisibility.appmenu.label
+         "Bar Hidlo Cyflym">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.toggleBarVisibility.button.tooltip):
+     The tooltip to display when hovering over the button on the tab bar that
+     toggles the visibility of the quick filter bar.
+     -->
+<!ENTITY quickFilterBar.toggleBarVisibility.button.tooltip
+         "Toglo'r bar hidlo cyflym">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.sticky.tooltip):
+     The tooltip to display when the user hovers over the sticky button
+     (currently displayed as a push-pin).  When active, the sticky button
+     causes the current filter settings to be retained when the user changes
+     folders or opens new tabs.  (When inactive, only the state of the text
+     filters are propagated between folder changes and when opening new tabs.)
+     -->
+<!ENTITY quickFilterBar.sticky.tooltip
+         "Cadw hidlau ar waith wrth newid ffolderi">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.unread.label):
+     The label for the filter button that causes us to filter results to only
+     include unread messages.
+     -->
+<!ENTITY quickFilterBar.unread.label
+         "Heb eu Darllen">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.unread.tooltip):
+     The tooltip for the filter button that causes us to filter results to only
+     include unread messages.
+     -->
+<!ENTITY quickFilterBar.unread.tooltip
+         "Dangos negeseuon heb eu darllen yn unig">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.starred.label):
+     The label for the filter button that causes us to filter results to only
+     include messages that have been starred/flagged.
+     -->
+<!ENTITY quickFilterBar.starred.label
+         "Serennog">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.starred.tooltip):
+     The tooltip for the filter button that causes us to filter results to only
+     include messages that have been starred/flagged.
+     -->
+<!ENTITY quickFilterBar.starred.tooltip
+         "Dangos dim ond negeseuon serennog">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.inaddrbook.label):
+     The label for the filter button that causes us to filter results to only
+     include messages from contacts in one of the user's non-remote address
+     books.
+     -->
+<!ENTITY quickFilterBar.inaddrbook.label
+         "Cysylltiad">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.inaddrbook.tooltip):
+     The tooltip for the filter button that causes us to filter results to only
+     include messages from contacts in one of the user's non-remote address
+     books.
+     -->
+<!ENTITY quickFilterBar.inaddrbook.tooltip
+         "Dangos dim ond negeseuon gan bobl yn eich llyfr cyfeiriadau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.tags.label):
+     The label for the filter button that causes us to filter results to only
+     include messages with at least one tag on them.
+     -->
+<!ENTITY quickFilterBar.tags.label
+         "Tagiau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.tags.tooltip):
+     The tooltip for the filter button that causes us to filter results to only
+     include messages with at least one tag on them.
+     -->
+<!ENTITY quickFilterBar.tags.tooltip
+         "Dangos dim ond negeseuon gyda thagiau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.attachment.label):
+     The label for the filter button that causes us to filter results to only
+     include messages with attachments.
+     -->
+<!ENTITY quickFilterBar.attachment.label
+         "Atodiad">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.attachment.tooltip):
+     The tooltip for the filter button that causes us to filter results to only
+     include messages with attachments.
+     -->
+<!ENTITY quickFilterBar.attachment.tooltip
+         "Dangos dim ond negeseuon gydag atodiadau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.resultsLabel.some.formatString):
+     This is used to populate the results box; it either displays the
+     number of messages found using this string, that there are no messages
+     (using quickFilterBar.resultsLabel.none), or the box is hidden.
+     This is a pluralizable string used to express the number of messages in
+     the results.  We replace the '#1' with the number of messages, otherwise
+     see the following URL For more information:
+     https://developer.mozilla.org/En/Localization_and_Plurals
+     -->
+<!ENTITY quickFilterBar.resultsLabel.some.formatString
+         "Dim negeseuon;#1 neges;#1 neges;#1 neges;#1 neges;#1 neges">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.resultsLabel.none):
+     The contents of the results box when there is a filter active but there
+     are no messages matching the filter.
+     -->
+<!ENTITY quickFilterBar.resultsLabel.none
+         "Dim canlyniadau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.resultsLabel.minWidth):
+     The minimum width, in pixels, of the results label.  Please size this
+     so that a 3 or 4 digit number of messages in the results can be displayed
+     without growing the size of the box.  You can tell this has been
+     accomplished if adding a filter constraint that changes the displayed
+     string to your "no results" string does not result in any changes to the
+     size of the text box to the label's right.  (If your string for
+     "no results" is longer than the "#### messages" case, then size for that.
+     -->
+<!ENTITY quickFilterBar.resultsLabel.minWidth
+         "100">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textbox.emptyText.base1):
+     This is the base of the empty text for the text search box.  We replace
+     #1 with the contents of the appropriate
+     quickFilterBar.textbox.emptyText.keyLabel.* value for the platform.
+     The goal is to convey to the user that typing in the box will filter
+     the messages and that there is a hotkey they can press to get to the
+     box faster.
+     -->
+<!ENTITY quickFilterBar.textbox.emptyText.base1
+         "Hidlo'r negeseuon hyn #1">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.show.key2):
+     This is the key used to show the quick filter bar. -->
+<!ENTITY quickFilterBar.show.key2
+         "k">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textbox.emptyText.keyLabel.nonmac):
+     The description of the key-binding to get into the box on windows and
+     linux (which use the control key).  This should match the value of
+     quickFilterBar.show.key above.
+     -->
+<!ENTITY quickFilterBar.textbox.emptyText.keyLabel2.nonmac
+         "&lt;Ctrl+Shift+K&gt;">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textbox.emptyText.keyLabel.mac):
+     The description of the key-binding to get into the box on mac systems.
+     This should match the value of quickFilterBar.show.key above.
+     -->
+<!ENTITY quickFilterBar.textbox.emptyText.keyLabel2.mac
+         "&lt;&#x21E7;&#x2318;K&gt;">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.booleanMode.tooltip):
+     Tooltip of the Any of / All of tagging mode selector.
+     -->
+<!ENTITY quickFilterBar.booleanMode.tooltip "Modd hidlo tagiau">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.booleanModeAny.label):
+     Tooltip of the Any of / All of tagging mode selector.
+     -->
+<!ENTITY quickFilterBar.booleanModeAny.label "Unrhyw un o">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.booleanModeAny.tooltip):
+     Tooltip of the Any of / All of tagging mode selector.
+     -->
+<!ENTITY quickFilterBar.booleanModeAny.tooltip "Dylai o leiaf un o'r meini prawf tag hyn gydweddu">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.booleanModeAll.label):
+     Tooltip of the Any of / All of tagging mode selector.
+     -->
+<!ENTITY quickFilterBar.booleanModeAll.label "Pob un">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.booleanModeAll.tooltip):
+     Tooltip of the Any of / All of tagging mode selector.
+     -->
+<!ENTITY quickFilterBar.booleanModeAll.tooltip "Dylai pob un o'r meini prawf tag hyn gydweddu">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textbox.idealWidth):
+     The number of pixels for the ideal width of the quick filter box textbox.
+     Choose this value so that the emptyText fits nicely with a little bit of
+     extra whitespace.
+     -->
+<!ENTITY quickFilterBar.textbox.idealWidth
+         "320">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textbox.minWidth):
+     The minimum width of the quick filter textbox in pixels.  This is the size
+     which we should refuse to flex below.  When we hit this size, the buttons
+     with labels will have their labels collapsed.
+     -->
+<!ENTITY quickFilterBar.textbox.minWidth
+         "280">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textFilter.explanation.label):
+     This label explains what the sender/recipients/subject/body buttons do.
+     This string should ideally be kept short because the label and the text
+     filter buttons share their bar (that appears when there is text in the text
+     filter box) with the list of tags when the tag filter is active, and the
+     tag sub-bar wants as much space as possible.  (Overflow is handled by an
+     arrow scroll box.)
+     -->
+<!ENTITY quickFilterBar.textFilter.explanation.label
+         "Hidlo negeseuon yn ôl:">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textFilter.sender.label):
+     The button label that toggles whether the text filter searches the message
+     sender for the string.
+     -->
+<!ENTITY quickFilterBar.textFilter.sender.label
+         "Anfonwr">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textFilter.recipients.label):
+     The button label that toggles whether the text filter searches the message
+     recipients (to, cc) for the string.
+     -->
+<!ENTITY quickFilterBar.textFilter.recipients.label
+         "Derbynwyr">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textFilter.subject.label):
+     The button label that toggles whether the text filter searches the message
+     subject for the string.
+     -->
+<!ENTITY quickFilterBar.textFilter.subject.label
+         "Pwnc">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.textFilter.body.label):
+     The button label that toggles whether the text filter searches the message
+     body for the string.
+     -->
+<!ENTITY quickFilterBar.textFilter.body.label
+         "Corff">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.glodaUpsell.continueSearch):
+     The first line of the panel popup that tells the user we found no matches
+     but we can convert to a global search for them.
+     -->
+<!ENTITY quickFilterBar.glodaUpsell.continueSearch
+         "Parhau i chwilio pob ffolder">
+
+<!-- LOCALIZATION NOTE (quickFilterBar.glodaUpsell.pressEnterAndCurrent):
+     The second line of the panel popup that tells the user we found no matches.
+     This line will have #1 replaced with what the user has typed so far.
+     -->
+<!ENTITY quickFilterBar.glodaUpsell.pressEnterAndCurrent
+         "Pwyswch 'Enter' eto i barhau i chwilio am: #1">
diff --git a/l10n-cy/mail/chrome/messenger/removeAccount.dtd b/l10n-cy/mail/chrome/messenger/removeAccount.dtd
new file mode 100644
index 0000000000..063af3c957
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/removeAccount.dtd
@@ -0,0 +1,22 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY dialogTitle                  "Tynnu Cyfrif a Data">
+<!ENTITY removeButton.label           "Tynnu">
+<!ENTITY removeButton.accesskey       "T">
+<!ENTITY removeAccount.label          "Tynnu manylion cyfrif">
+<!ENTITY removeAccount.accesskey      "c">
+<!ENTITY removeAccount.desc           "Bydd yn tynnu gwybodaeth &brandShortName; am y cyfrif hwn, yn unig. Nid yw'n effeithio ar y cyfrif ei hun ar y gweinydd.">
+<!ENTITY removeData.label             "Tynnu data negeseuon">
+<!ENTITY removeData.accesskey         "d">
+<!ENTITY removeDataChat.label         "Tynnu data sgwrs">
+<!ENTITY removeDataChat.accesskey     "s">
+<!ENTITY removeDataLocalAccount.desc  "Bydd yn tynnu'r holl negeseuon, ffolderi a hidlau sy'n gysylltiedig â'r cyfrif hwn o'ch disg lleol. Nid yw hyn yn effeithio ar rhai negeseuon sy'n cael eu cadw ar y gweinydd. Peidiwch â dewis hwn os ydych yn bwriadu archifo'r data lleol neu ei ailddefnyddio yn ddiweddarach o fewn &brandShortName;.">
+<!ENTITY removeDataServerAccount.desc "Bydd yn tynnu'r holl negeseuon, ffolderi a hidlau sy'n gysylltiedig â'r cyfrif hwn o'ch disg. Bydd eich negeseuon a'ch ffolderi yn cael eu cadw ar y gweinydd.">
+<!ENTITY removeDataChatAccount.desc   "Yn tynnu pob cofnod o sgyrsiau sydd wedi eu cadw ar gyfer y cyfrif hwn ar eich disg lleol.">
+<!ENTITY showData.label               "Dangos lleoliad y data">
+<!ENTITY showData.accesskey           "l">
+<!ENTITY progressPending              "Tynnu data penodol…">
+<!ENTITY progressSuccess              "Llwyddodd y tynnu.">
+<!ENTITY progressFailure              "Methodd y tynnu.">
diff --git a/l10n-cy/mail/chrome/messenger/removeAccount.properties b/l10n-cy/mail/chrome/messenger/removeAccount.properties
new file mode 100644
index 0000000000..04d2fbf3aa
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/removeAccount.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+removeQuestion=Ydych chi'n siŵr eich bod am dynnu'r cyfrif "%S"?
diff --git a/l10n-cy/mail/chrome/messenger/renameFolderDialog.dtd b/l10n-cy/mail/chrome/messenger/renameFolderDialog.dtd
new file mode 100644
index 0000000000..47beecf007
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/renameFolderDialog.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+   
+<!ENTITY renameFolderDialog.title          "Ailenwi'r Ffolder">
+<!ENTITY rename.label                      "Rhowch enw newydd i'ch ffolder:">
+<!ENTITY rename.accesskey                  "R">
+<!ENTITY accept.label                      "Ailenwi">
+<!ENTITY accept.accesskey                  "A">
diff --git a/l10n-cy/mail/chrome/messenger/safeMode.dtd b/l10n-cy/mail/chrome/messenger/safeMode.dtd
new file mode 100644
index 0000000000..804c8dae23
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/safeMode.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY safeModeDialog.title             "Modd Diogel &brandShortName;">
+<!ENTITY window.width                     "37em">
+
+<!ENTITY safeModeDescription.label        "Mae &brandShortName; yn rhedeg yn y Modd Diogel, sy'n anablu dros dro eich gosodiadau cyfaddas personol, themâu a'ch estyniadau dros dro.">
+<!ENTITY safeModeDescription2.label       "Mae modd gwneud rhai neu'r holl newidiadau'n rhai parhaol:">
+
+<!ENTITY disableAddons.label              "Atal pob ychwanegyn">
+<!ENTITY disableAddons.accesskey          "t">
+
+<!ENTITY resetToolbars.label              "Ailosod barau offer a rheolyddion">
+<!ENTITY resetToolbars.accesskey          "i">
+
+<!ENTITY changeAndRestartButton.label     "Gosod Newidiadau ac Ailgychwyn">
+<!ENTITY changeAndRestartButton.accesskey "G">
+
+<!ENTITY continueButton.label             "Parhau yn y Modd Diogel">
+<!ENTITY continueButton.accesskey         "D">
diff --git a/l10n-cy/mail/chrome/messenger/sanitize.dtd b/l10n-cy/mail/chrome/messenger/sanitize.dtd
new file mode 100644
index 0000000000..6538dfb0ee
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/sanitize.dtd
@@ -0,0 +1,42 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY sanitizeDialog2.title         "Clirio Hanes Diweddar">
+
+<!-- XXX rearrange entities to match physical layout when l10n isn't an issue -->
+<!-- LOCALIZATION NOTE (clearTimeDuration.*): "Time range to clear" dropdown.
+     See UI mockup at bug 480169 -->
+<!ENTITY clearTimeDuration.label          "Ystod amser i'w glirio: ">
+<!ENTITY clearTimeDuration.accesskey      "Y">
+<!ENTITY clearTimeDuration.lastHour       "Awr Olaf">
+<!ENTITY clearTimeDuration.last2Hours     "Dwy Awr Olaf">
+<!ENTITY clearTimeDuration.last4Hours     "Pedair Awr Olaf">
+<!ENTITY clearTimeDuration.today          "Heddiw">
+<!ENTITY clearTimeDuration.everything     "Popeth">
+<!-- Localization note (clearTimeDuration.suffix) - trailing entity for languages
+that require it.  -->
+<!ENTITY clearTimeDuration.suffix         "">
+
+<!-- LOCALIZATION NOTE (detailsProgressiveDisclosure.*): Labels and accesskeys
+     of the "Details" progressive disclosure button.  See UI mockup at bug
+     480169 -->
+<!ENTITY detailsProgressiveDisclosure.label     "Manylion">
+<!ENTITY detailsProgressiveDisclosure.accesskey "M">
+
+
+<!ENTITY historyGroup.label                "Hanes">
+
+<!ENTITY itemHistory.label                 "Hanes Pori">
+<!ENTITY itemHistory.accesskey             "H">
+<!ENTITY itemCookies.label                 "Cwcis">
+<!ENTITY itemCookies.accesskey             "C">
+<!ENTITY itemCache.label                   "Storfa">
+<!ENTITY itemCache.accesskey               "S">
+
+<!-- LOCALIZATION NOTE (sanitizeEverythingUndoWarning): Second warning paragraph
+     that appears when "Time range to clear" is set to "Everything".  See UI
+     mockup at bug 480169 -->
+<!ENTITY sanitizeEverythingUndoWarning     "Nid oes modd dadwneud y weithred.">
+
+<!ENTITY dialog.width                 "28em">
diff --git a/l10n-cy/mail/chrome/messenger/seamonkeyImportMsgs.properties b/l10n-cy/mail/chrome/messenger/seamonkeyImportMsgs.properties
new file mode 100644
index 0000000000..806c332e89
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/seamonkeyImportMsgs.properties
@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#
+# The following are used by the seamonkey import code to display status/error
+# and informational messages
+
+# Short name of import module
+SeamonkeyImportName=SeaMonkey
+
+# Description of import module
+SeamonkeyImportDescription=Mewnforio llyfrau cyfeiriadau, e-bost a chyfrifon o SeaMonkey.
+
+# Success Message for addressbook import
+SeamonkeyImportAddressSuccess=Mewnforiwyd llyfrau cyfeiriadau yn llwyddiannus.
+
+# Success Message for mail import
+SeamonkeyImportSettingsSuccess=Mewnforiwyd negeseuon a chyfrifon lleol yn llwyddiannus.
diff --git a/l10n-cy/mail/chrome/messenger/search-attributes.properties b/l10n-cy/mail/chrome/messenger/search-attributes.properties
new file mode 100644
index 0000000000..db5130802d
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/search-attributes.properties
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#these need to match nsMsgSearchAttrib interface in nsMsgSearchCore.idl
+#and nsMsgSearchAttribMap in nsMsgSearchAdapter.cpp
+Subject=Pwnc
+From=Oddi wrth
+Body=Corff
+Date=Dyddiad
+Priority=Blaenoriaeth
+Status=Statws
+To=At
+Cc=Cc
+ToOrCc=To neu Cc
+AgeInDays=Oed mewn Dyddiau
+SizeKB=Maint (KB)
+Tags=Tagiau
+# for AB and LDAP
+AnyName=Unrhyw Enw
+DisplayName=Dangos Enw
+Nickname=Llysenw
+ScreenName=Enw Sgrin
+Email=E-bost
+AdditionalEmail=E-bost Ychwanegol
+AnyNumber=Unrhyw Rif
+WorkPhone=Rhif Ffôn Gwaith
+HomePhone=Rhif Ffôn Cartref
+Fax=Ffacs
+Pager=Swnyn
+Mobile=Ffôn Symudol
+City=Tref/Dinas
+Street=Stryd
+Title=Teitl
+Organization=Corff
+Department=Adran
+# more mailnews
+FromToCcOrBcc=Oddi wrth, At, Cc neu Bcc
+JunkScoreOrigin=Tarddiad Sgôr Sbam
+JunkPercent=Canran Sbam
+AttachmentStatus=Statws Atodiad
+JunkStatus=Statws Sbam
+Label=Label
+Customize=Cyfaddasu…
+MissingCustomTerm=Term Cyfaddas Coll
diff --git a/l10n-cy/mail/chrome/messenger/search-operators.properties b/l10n-cy/mail/chrome/messenger/search-operators.properties
new file mode 100644
index 0000000000..f70f751961
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/search-operators.properties
@@ -0,0 +1,31 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+0=yn cynnwys
+1=nid yw'n cynnwys
+2=yn
+3=nid yw'n
+4=yn wag
+
+5=o flaen
+6=ar ôl
+    
+7=yn uwch na
+8=yn is na
+
+9=yn cychwyn gyda
+10=yn gorffen gyda
+
+11=yn swnio fel
+12=LdapDwim
+
+13=yn fwy na
+14=yn llai na
+
+15=Cwblhau Enw
+16=yn fy llyfr cyfeiriadau
+17=nid yw yn fy llyfr cyfeiriadau
+18=nid yw'n wag
+19=yn cydweddu â
+20=nid yw'n cydweddu â
diff --git a/l10n-cy/mail/chrome/messenger/search.properties b/l10n-cy/mail/chrome/messenger/search.properties
new file mode 100644
index 0000000000..4ce66fa2ed
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/search.properties
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# these are the fields that get inserted in the search line
+# for "and" searches, this looks like:
+#
+# searchAnd0 <attribute> searchAnd1 <operator> searchAnd2 <value> searchAnd4
+#
+# for example, in english this looks like:
+# and the [Sender ] [doesn't contain] [John]
+#
+# TODO: need to special-case the first line (filterindex==0)
+
+# filter stuff
+
+searchingMessage=Chwilio…
+# LOCALIZATION NOTE (matchesFound): #1 number of matches found
+matchesFound=wedi canfod #1 sy'n cydweddu;wedi canfod #1 sy'n cydweddu
+noMatchesFound=Heb ganfod cydweddiad
+labelForStopButton=Atal
+labelForSearchButton=Chwilio
+labelForStopButton.accesskey=A
+labelForSearchButton.accesskey=C
+
+moreButtonTooltipText=Ychwanegu rheol newydd
+lessButtonTooltipText=Tynnu'r rheol
diff --git a/l10n-cy/mail/chrome/messenger/searchTermOverlay.dtd b/l10n-cy/mail/chrome/messenger/searchTermOverlay.dtd
new file mode 100644
index 0000000000..6fa4783d85
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/searchTermOverlay.dtd
@@ -0,0 +1,19 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY matchAll.label     "Cydweddu â'r canlynol i gyd">
+<!ENTITY matchAll.accesskey "y">
+<!ENTITY matchAny.label     "Cydweddu ag unrhyw un o'r canlynol">
+<!ENTITY matchAny.accesskey "d">
+<!ENTITY matchAllMsgs.label     "Cydweddu pob neges">
+<!ENTITY matchAllMsgs.accesskey "n">
+<!-- LOCALIZATION NOTE
+  The values below are used to control the widths of the search widgets.
+  Change the values only when the localized strings in the popup menus
+  are truncated in the widgets.
+ -->
+
+<!ENTITY searchTermListAttributesFlexValue "1">
+<!ENTITY searchTermListOperatorsFlexValue "1">
+<!ENTITY searchTermListValueFlexValue "3">
diff --git a/l10n-cy/mail/chrome/messenger/shutdownWindow.properties b/l10n-cy/mail/chrome/messenger/shutdownWindow.properties
new file mode 100644
index 0000000000..2064a7f58b
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/shutdownWindow.properties
@@ -0,0 +1,10 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# These strings are loaded and represented by the XUL dialog.
+shutdownDialogTitle=Diffodd Ffenestr Cynnydd
+taskProgress=Prosesu %1$S o %2$S o Dasgau\u0020
+
+# These strings are loaded by the individual shutdown tasks.
diff --git a/l10n-cy/mail/chrome/messenger/smime.properties b/l10n-cy/mail/chrome/messenger/smime.properties
new file mode 100644
index 0000000000..da65e4a0a0
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/smime.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the smime content type handler
+#
+
+## @name NS_MSG_UNABLE_TO_OPEN_FILE
+## LOCALIZATION NOTE: the text can contain HTML tags. 
+1000=Mae hon yn neges <B>ENCRYPTED</B> or <B>SIGNED</B>.<br> Nid yw'r rhaglen hon yn cynnal e-bost wedi ei hamgryptio na'i llofnodi.
+
+
diff --git a/l10n-cy/mail/chrome/messenger/smtpEditOverlay.dtd b/l10n-cy/mail/chrome/messenger/smtpEditOverlay.dtd
new file mode 100644
index 0000000000..4ccbc1e315
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/smtpEditOverlay.dtd
@@ -0,0 +1,24 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY settings.caption "Gosodiadau">
+<!ENTITY security.caption "Diogelwch a Dilysu">
+<!ENTITY serverName.label "Enw'r Gweinydd:">
+<!ENTITY serverName.accesskey "G">
+<!ENTITY serverDescription.label "Disgrifiad:">
+<!ENTITY serverDescription.accesskey "D">
+<!ENTITY serverPort.label "Porth:">
+<!ENTITY serverPort.accesskey "P">
+<!ENTITY userName.label "Enw Defnyddiwr:">
+<!ENTITY userName.accesskey "E">
+<!ENTITY connectionSecurity.label "Diogelwch y cysylltiad:">
+<!ENTITY connectionSecurity.accesskey "D">
+<!ENTITY connectionSecurityType-0.label "Dim">
+<!ENTITY connectionSecurityType-1.label "STARTTLS, os ar gael">
+<!ENTITY connectionSecurityType-2.label "STARTTLS">
+<!ENTITY connectionSecurityType-3.label "SSL/TLS">
+<!ENTITY smtpEditTitle.label "Gweinydd SMTP">
+<!ENTITY serverPortDefault.label "Rhagosodedig:">
+<!ENTITY authMethod.label "Dull dilysu:">
+<!ENTITY authMethod.accesskey "u">
diff --git a/l10n-cy/mail/chrome/messenger/subscribe.dtd b/l10n-cy/mail/chrome/messenger/subscribe.dtd
new file mode 100644
index 0000000000..69988a69fa
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/subscribe.dtd
@@ -0,0 +1,22 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY subscribeDialog.title        "Tanysgrifio">
+<!ENTITY subscribeButton.label        "Tanysgrifio">
+<!ENTITY subscribeButton.accesskey    "s">
+<!ENTITY unsubscribeButton.label      "Dad-danysgrifio">
+<!ENTITY unsubscribeButton.accesskey  "D">
+<!ENTITY newGroupsTab.label           "Grwpiau Newydd">
+<!ENTITY newGroupsTab.accesskey       "G">
+<!ENTITY refreshButton.label          "Adnewyddu">
+<!ENTITY refreshButton.accesskey      "A">
+<!ENTITY stopButton.label             "Atal">
+<!ENTITY stopButton.accesskey         "t">
+<!ENTITY server.label                 "Cyfrif:">
+<!ENTITY server.accesskey             "C">
+<!ENTITY subscribedHeader.label       "Tanysgrifio">
+<!-- commenting out until bug 38906 is fixed 
+<!ENTITY messagesHeader.label         "Messages"> -->
+<!ENTITY namefield.label              "Dangos eitemau sy'n cynnwys:">
+<!ENTITY namefield.accesskey          "D">
diff --git a/l10n-cy/mail/chrome/messenger/subscribe.properties b/l10n-cy/mail/chrome/messenger/subscribe.properties
new file mode 100644
index 0000000000..ace52d541b
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/subscribe.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+subscribeLabel-nntp=Dewis y grwpiau newyddion i danysgrifio iddynt:
+subscribeLabel-imap=Dangos y ffolderi i danysgrifio iddynt:
+currentListTab-nntp.label=Rhestr Grwpiau Cyfredol
+currentListTab-nntp.accesskey=C
+currentListTab-imap.label=Rhestr Ffolderi
+currentListTab-imap.accesskey=F
+pleaseWaitString=Arhoswch…
+offlineState=Rydych all-lein. Nid oedd modd estyn eitemau oddi ar y gweinydd.
+errorPopulating=Gwall wrth estyn eitemau o'r gweinydd.
diff --git a/l10n-cy/mail/chrome/messenger/tabmail.dtd b/l10n-cy/mail/chrome/messenger/tabmail.dtd
new file mode 100644
index 0000000000..ee27184cfb
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/tabmail.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  closeTab.label           "Cau'r Tab">
+<!ENTITY  listAllTabs.label        "Rhestru pob tab">
+<!-- LOCALIZATION NOTE(defaultTabTitle.label): This is the default tab
+     title to show when the tab has no title. -->
+<!ENTITY  defaultTabTitle.label    "Cartref">
diff --git a/l10n-cy/mail/chrome/messenger/taskbar.properties b/l10n-cy/mail/chrome/messenger/taskbar.properties
new file mode 100644
index 0000000000..21d0132743
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/taskbar.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+taskbar.tasks.composeMessage.label=Ysgrifennu neges newydd
+taskbar.tasks.composeMessage.description=Ysgrifennu neges newydd.
+taskbar.tasks.openAddressBook.label=Agor llyfr cyfeiriadau
+taskbar.tasks.openAddressBook.description=Agor eich llyfr cyfeiriadau.
diff --git a/l10n-cy/mail/chrome/messenger/telemetry.properties b/l10n-cy/mail/chrome/messenger/telemetry.properties
new file mode 100644
index 0000000000..c736bd9b66
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/telemetry.properties
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Telemetry prompt
+# LOCALIZATION NOTE (telemetryText): %1$S will be replaced by brandFullName,
+# and %2$S by the value of the toolkit.telemetry.server_owner preference.
+telemetryText = Hoffech chi gynorthwyo i wella %1$S drwy gofnodi'n awtomatig defnydd cof, perfformiad ac ymatebolrwydd i %2$S?
+telemetryLinkLabel = Dysgu Rhagor
+telemetryYesButtonLabel = Iawn
+telemetryYesButtonAccessKey = I
+telemetryNoButtonLabel = Na
+telemetryNoButtonAccessKey = N
diff --git a/l10n-cy/mail/chrome/messenger/templateUtils.properties b/l10n-cy/mail/chrome/messenger/templateUtils.properties
new file mode 100644
index 0000000000..12e007477c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/templateUtils.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE yesterday: used in various places where we compute
+# a "friendly" date, e.g. displaying that a message was from yesterday.
+yesterday=ddoe
diff --git a/l10n-cy/mail/chrome/messenger/textImportMsgs.properties b/l10n-cy/mail/chrome/messenger/textImportMsgs.properties
new file mode 100644
index 0000000000..6a2e7b96d6
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/textImportMsgs.properties
@@ -0,0 +1,48 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the outlook express import code to display status/error 
+# and informational messages
+#
+
+#
+# The following are used by the outlook express import code to display status/error
+# and informational messages
+#
+
+# Short name of import module
+## @name TEXTIMPORT_NAME
+## @loc None
+2000=Ffeil testun (LDIF, .tab, .csv, .txt)
+
+# Description of import module
+## @name TEXTIMPORT_DESCRIPTION
+## @loc None
+2001=Mewnforio llyfr cyfeiriadau o ffeil testun, gan gynnwys fformatau  LDIF (.ldif, .ldi), tab dadamffinedig (.tab, .txt) coma gwahanedig (.csv).
+
+# Description of import module
+## @name TEXTIMPORT_ADDRESS_NAME
+## @loc None
+2002=Llyfr Cyfeiriadau Testun
+
+# Description
+## @name TEXTIMPORT_ADDRESS_SUCCESS
+## @loc None
+2003=Llyfr cyfeiriadau wedi'i fewnforio %S
+
+# Error message
+## @name TEXTIMPORT_ADDRESS_BADPARAM
+## @loc None
+2004=Paramedr gwael wedi'i basio i'r llyfr cyfeiriadau.
+
+# Error message
+## @name TEXTIMPORT_ADDRESS_BADSOURCEFILE
+## @loc None
+2005=Gwall wrth gael mynediad ar gyfer llyfr cyfeiriadau %S.
+
+# Error message
+## @name TEXTIMPORT_ADDRESS_CONVERTERROR
+## @loc None
+2006=Gwall wrth fewnforio llyfr cyfeiriadau %S, efallai nad yw'r holl gyfeiriadau wedi'u mewnforio.
diff --git a/l10n-cy/mail/chrome/messenger/vCardImportMsgs.properties b/l10n-cy/mail/chrome/messenger/vCardImportMsgs.properties
new file mode 100644
index 0000000000..2ebcd34088
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/vCardImportMsgs.properties
@@ -0,0 +1,26 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the vCard import code to display status, error, and
+# informational messages
+#
+
+vCardImportName=Ffeil vCard (.vcf)
+
+vCardImportDescription=Mewnforio llyfr cyfeiriadau ar ffurf fformat vCard
+
+vCardImportAddressName=Llyfr Cyfeiriadau vCard
+
+# LOCALIZATION NOTE (vCardImportAddressSuccess): %S is replaced by the
+# name of the address book being imported.
+vCardImportAddressSuccess=Llyfr cyfeiriadau wedi'i fewnforio %S
+
+# LOCALIZATION NOTE (vCardImportAddressSuccess): %S is replaced by the
+# name of the address book being imported.
+vCardImportAddressBadSourceFile=Gwall wrth gael mynediad ar gyfer llyfr cyfeiriadau %S.
+
+# LOCALIZATION NOTE (vCardImportAddressSuccess): %S is replaced by the
+# name of the address book being imported.
+vCardImportAddressConvertError=Gwall wrth fewnforio llyfr cyfeiriadau %S, efallai nad yw'r holl gyfeiriadau wedi'u mewnforio.
diff --git a/l10n-cy/mail/chrome/messenger/viewLog.dtd b/l10n-cy/mail/chrome/messenger/viewLog.dtd
new file mode 100644
index 0000000000..05111c4d37
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/viewLog.dtd
@@ -0,0 +1,12 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY viewLog.title "Cofnod Hidl">
+<!ENTITY viewLogInfo.text "Mae'r Cofnod Hidl yn cofnodi'r hidlau sydd wedi'u rhedeg ar y cyfrif. Defnyddiwch y blwch ticio isod i alluogi cofnodi.">
+<!ENTITY clearLog.label "Clirio'r Cofnod">
+<!ENTITY clearLog.accesskey "C">
+<!ENTITY enableLog.label "Galluogi Cofnod Hidl">
+<!ENTITY enableLog.accesskey "G">
+<!ENTITY closeLog.label "Cau">
+<!ENTITY closeLog.accesskey "u">
diff --git a/l10n-cy/mail/chrome/messenger/viewSource.dtd b/l10n-cy/mail/chrome/messenger/viewSource.dtd
new file mode 100644
index 0000000000..9d2480e875
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/viewSource.dtd
@@ -0,0 +1,90 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- extracted from content/viewSource.xul -->
+
+<!-- extracted from content/viewSource.xhtml -->
+
+<!-- LOCALIZATION NOTE (mainWindow.title) : DONT_TRANSLATE -->
+<!ENTITY mainWindow.title "&brandFullName;">
+<!-- LOCALIZATION NOTE (mainWindow.titlemodifier) : DONT_TRANSLATE -->
+<!ENTITY mainWindow.titlemodifier "&brandFullName;">
+<!-- LOCALIZATION NOTE (mainWindow.titlemodifierseparator) : DONT_TRANSLATE -->
+<!ENTITY mainWindow.titlemodifierseparator " - ">
+<!ENTITY mainWindow.preface "Ffynhonnell: ">
+
+<!ENTITY editMenu.label "Golygu">
+<!ENTITY editMenu.accesskey "G">
+<!ENTITY fileMenu.label "Ffeil">
+<!ENTITY fileMenu.accesskey "F">
+<!ENTITY savePageCmd.label "Cadw Tudalen Fel…">
+<!ENTITY savePageCmd.accesskey "C">
+<!ENTITY savePageCmd.commandkey "S">
+<!ENTITY pageSetupCmd.label "Gosodiad Tudalen…">
+<!ENTITY pageSetupCmd.accesskey "G">
+<!ENTITY printPreviewCmd.label "Rhagolwg Argraffu">
+<!ENTITY printPreviewCmd.accesskey "h">
+<!ENTITY printCmd.label "Argraffu…">
+<!ENTITY printCmd.accesskey "A">
+<!ENTITY printCmd.commandkey "P">
+<!ENTITY closeCmd.label "Cau">
+<!ENTITY closeCmd.accesskey "C">
+<!ENTITY closeCmd.commandkey "W">
+
+<!-- LOCALIZATION NOTE :
+textEnlarge.commandkey3, textReduce.commandkey2 and
+textReset.commandkey2 are alternative acceleration keys for zoom.
+If shift key is needed with your locale popular keyboard for them,
+you can use these alternative items. Otherwise, their values should be empty.  -->
+
+<!ENTITY textEnlarge.commandkey "+">
+<!ENTITY textEnlarge.commandkey2 "=">
+<!ENTITY textEnlarge.commandkey3 "">
+<!ENTITY textReduce.commandkey "-">
+<!ENTITY textReduce.commandkey2 "">
+<!ENTITY textReset.commandkey "0">
+<!ENTITY textReset.commandkey2 "">
+
+<!ENTITY goToLineCmd.label "Mynd i Linell…">
+<!ENTITY goToLineCmd.accesskey "M">
+<!ENTITY goToLineCmd.commandkey "l">
+
+<!ENTITY viewMenu.label           "Golwg">
+<!ENTITY viewMenu.accesskey       "o">
+<!ENTITY reloadCmd.label "Ail-lwytho">
+<!ENTITY reloadCmd.accesskey "A">
+<!ENTITY reloadCmd.commandkey "r">
+<!ENTITY menu_wrapLongLines.title "Amlapio Llinellau Hir">
+<!ENTITY menu_wrapLongLines.accesskey "L">
+<!ENTITY menu_highlightSyntax.label "Amlygu Cystrawen">
+<!ENTITY menu_highlightSyntax.accesskey "m">
+<!ENTITY menu_textSize.label "Maint Testun">
+<!ENTITY menu_textSize.accesskey "T">
+<!ENTITY menu_textEnlarge.label "Cynyddu">
+<!ENTITY menu_textEnlarge.accesskey "y">
+<!ENTITY menu_textReduce.label "Lleihau">
+<!ENTITY menu_textReduce.accesskey "L">
+<!ENTITY menu_textReset.label "Arferol">
+<!ENTITY menu_textReset.accesskey "A">
+
+<!ENTITY findOnCmd.label     "Canfod ar y Dudalen…">
+<!ENTITY findOnCmd.accesskey "D">
+<!ENTITY findOnCmd.commandkey "f">
+<!ENTITY findAgainCmd.label  "Canfod Eto">
+<!ENTITY findAgainCmd.accesskey "E">
+<!ENTITY findAgainCmd.commandkey "g">
+<!ENTITY findAgainCmd.commandkey2 "VK_F3">
+<!ENTITY findSelectionCmd.commandkey "e">
+
+<!ENTITY backCmd.label "Nôl">
+<!ENTITY backCmd.accesskey "N">
+<!ENTITY forwardCmd.label "Ymlaen">
+<!ENTITY forwardCmd.accesskey "Y">
+<!ENTITY goBackCmd.commandKey "[">
+<!ENTITY goForwardCmd.commandKey "]">
+
+<!ENTITY copyLinkCmd.label "Copïo Lleoliad Dolen">
+<!ENTITY copyLinkCmd.accesskey "L">
+<!ENTITY copyEmailCmd.label "Copïo Cyfeiriad E-bost">
+<!ENTITY copyEmailCmd.accesskey "E">
diff --git a/l10n-cy/mail/chrome/messenger/viewSource.properties b/l10n-cy/mail/chrome/messenger/viewSource.properties
new file mode 100644
index 0000000000..60f65d960b
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/viewSource.properties
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+goToLineTitle     = Mynd i llinell
+goToLineText      = Rhowch rif y llinell
+invalidInputTitle = Mewnbwn annilys
+invalidInputText  = Mae'r rhif roddwyd yn annilys.
+outOfRangeTitle   = Heb ganfod y llinell
+outOfRangeText    = Heb ganfod y llinell hon.
+viewSelectionSourceTitle = Ffynhonnell DOM Dewis
+viewMathMLSourceTitle    = Ffynhonnell DOM MathML
+
+context_goToLine_label        = Mynd i Llinell…
+context_goToLine_accesskey    = L
+context_wrapLongLines_label   = Amlapio Llinellau Hir
+context_highlightSyntax_label = Amlygu Cystrawen
diff --git a/l10n-cy/mail/chrome/messenger/viewZoomOverlay.dtd b/l10n-cy/mail/chrome/messenger/viewZoomOverlay.dtd
new file mode 100644
index 0000000000..f024b9ac6a
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/viewZoomOverlay.dtd
@@ -0,0 +1,32 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE :
+fullZoomEnlargeCmd.commandkey3, fullZoomReduceCmd.commandkey2 and
+fullZoomResetCmd.commandkey2 are alternative acceleration keys for zoom.
+If shift key is needed with your locale popular keyboard for them,
+you can use these alternative items. Otherwise, their values should be empty.  -->
+
+
+<!ENTITY fullZoomEnlargeCmd.label       "Chwyddo Mewn">
+<!ENTITY fullZoomEnlargeCmd.accesskey   "M">
+<!ENTITY fullZoomEnlargeCmd.commandkey  "+">
+<!-- + is above this key on many keyboards -->
+<!ENTITY fullZoomEnlargeCmd.commandkey2 "="> 
+<!ENTITY fullZoomEnlargeCmd.commandkey3 "">
+
+<!ENTITY fullZoomReduceCmd.label        "Chwyddo Allan">
+<!ENTITY fullZoomReduceCmd.accesskey    "A">
+<!ENTITY fullZoomReduceCmd.commandkey   "-">
+<!ENTITY fullZoomReduceCmd.commandkey2  "">
+
+<!ENTITY fullZoomResetCmd.label         "Ailosod">
+<!ENTITY fullZoomResetCmd.accesskey     "A">
+<!ENTITY fullZoomResetCmd.commandkey    "0">
+<!ENTITY fullZoomResetCmd.commandkey2   "">
+
+<!ENTITY fullZoomToggleCmd.label        "Chwyddo'r Testun yn Unig">
+<!ENTITY fullZoomToggleCmd.accesskey    "T">
+<!ENTITY fullZoom.label                 "Chwyddo">
+<!ENTITY fullZoom.accesskey             "C">
diff --git a/l10n-cy/mail/chrome/messenger/virtualFolderListDialog.dtd b/l10n-cy/mail/chrome/messenger/virtualFolderListDialog.dtd
new file mode 100644
index 0000000000..88bcc3b76c
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/virtualFolderListDialog.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY virtualFolderListTitle.title        "Dewis Ffolder(i)">
+<!ENTITY virtualFolderDesc.label       "Dewis ffolderi i'w chwilio:">
+
+
+<!ENTITY folderName.label "Enw ffolder">
+<!ENTITY folderSearch.label "Chwilio">
diff --git a/l10n-cy/mail/chrome/messenger/virtualFolderProperties.dtd b/l10n-cy/mail/chrome/messenger/virtualFolderProperties.dtd
new file mode 100644
index 0000000000..4ee6e55bc3
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/virtualFolderProperties.dtd
@@ -0,0 +1,22 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY virtualFolderProperties.title "Ffolder Chwilio wedi'i Chadw Newydd">
+<!ENTITY name.label                 "Enw:">
+<!ENTITY name.accesskey             "E">
+<!ENTITY description.label          "Creu fel is-ffolder o:">
+<!ENTITY description.accesskey      "i">
+
+<!ENTITY searchTermCaption.label "Ffurfweddu'r meini prawf chwilio ar gyfer y ffolder chwilio a gadwyd: ">
+
+<!ENTITY folderSelectionCaption.label "Dewis ffolderi i'w chwilio: ">
+<!ENTITY chooseFoldersButton.label "Dewis…">
+<!ENTITY chooseFoldersButton.accesskey "D">
+
+<!ENTITY searchOnline.label "Chwilio Ar-lein (Mae'n cynnig y canlyniadau diweddaraf ar ffolderi IMAP a Newyddion ond mae'n cymryd mwy o amser i agor y ffolder)">
+<!ENTITY searchOnline.accesskey "A">
+<!ENTITY newFolderButton.label       "Creu">
+<!ENTITY newFolderButton.accesskey   "r">
+<!ENTITY editFolderButton.label      "Diweddaru">
+<!ENTITY editFolderButton.accesskey  "D">
diff --git a/l10n-cy/mail/chrome/messenger/wmImportMsgs.properties b/l10n-cy/mail/chrome/messenger/wmImportMsgs.properties
new file mode 100644
index 0000000000..649a337245
--- /dev/null
+++ b/l10n-cy/mail/chrome/messenger/wmImportMsgs.properties
@@ -0,0 +1,76 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# The following are used by the windows live mail import code to display status/error
+# and informational messages
+#
+
+# Short name of import module
+## @name WMIMPORT_NAME
+## @loc None
+## LOCALIZATION NOTE (2000): DONT_TRANSLATE
+2000=Windows Live Mail
+
+# Description of import module
+## @name WMIMPORT_DESCRIPTION
+## @loc None
+## LOCALIZATION NOTE (2001): In this item, don't translate "Windows Live Mail"
+2001=Gosodiadau Windows Live Mail
+
+# Success message
+## @name WMIMPORT_MAILBOX_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2002): In this item, don't translate "%1$S" or "%2$d"
+## The variable %1$S will contain the name of the Mailbox
+## The variable %2$d will contain the number of messages
+2002=Blwch E-bost %1$S, wedi mewnforio %2$d neges
+
+# Error message
+## @name WMIMPORT_MAILBOX_BADPARAM
+## @loc None
+2003=Paramedr gwallus wedi'i basio i flwch e-bost mewnforio.
+
+# Error message
+## @name WMIMPORT_MAILBOX_BADSOURCEFILE
+## @loc None
+## LOCALIZATION NOTE (2004): In this item, don't translate "%S"
+## The variable %S will contain the name of the Mailbox
+2004=Gwall wrth gael mynediad i flwch e-bost %S.
+
+# Error message
+## @name WMIMPORT_MAILBOX_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2005): In this item, don't translate "%S"
+## The variable %S will contain the name of the Mailbox
+2005=Gwall wrth fewnforio blwch e-bost %S, efallai na fydd yr holl negeseuon yn cael eu mewnforio o'r blwch e-bost.
+
+# Default name of imported addressbook
+## @name WMIMPORT_DEFAULT_NAME
+## @loc None
+2006=Llyfr Cyfeiriadau Windows Live Mail
+
+# Autofind description
+## @name WMIMPORT_AUTOFIND
+## @loc None
+2007=Llyfr cyfeiriadau Windows Live Mail (llyfr cyfeiriadau windows)
+
+# Description
+## @name WMIMPORT_ADDRESS_SUCCESS
+## @loc None
+## LOCALIZATION NOTE (2006): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2008=Llyfr cyfeiriadau wedi'i fewnforio %S
+
+# Error message
+## @name WMIMPORT_ADDRESS_CONVERTERROR
+## @loc None
+## LOCALIZATION NOTE (2009): In this item, don't translate "%S"
+## The variable %S will receive the name of the address book
+2009=Gwall wrth fewnforio llyfr cyfeiriadau %S, efallai nad yw'r holl gyfeiriadau wedi'u mewnforio.
+
+# Error message
+## @name WMIMPORT_ADDRESS_BADPARAM
+## @loc None
+2010=Pasiwyd paramedrau gwallus i'r llyfr cyfeiriadau sydd wedi'i fewnforio.
diff --git a/l10n-cy/mail/chrome/mozldap/ldap.properties b/l10n-cy/mail/chrome/mozldap/ldap.properties
new file mode 100644
index 0000000000..026909b197
--- /dev/null
+++ b/l10n-cy/mail/chrome/mozldap/ldap.properties
@@ -0,0 +1,272 @@
+# 
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The following two strings are used when prompting the user for authentication
+# information:
+
+## @name AUTH_PROMPT_TITLE
+## @loc none
+authPromptTitle=Angen Cyfrinair Gweinydd LDAP
+
+## @name AUTH_PROMPT_TEXT
+## @loc %1$S should not be localized.  It is the hostname of the LDAP server.
+authPromptText=Rhowch eich cyfrinair ar gyfer %1$S.
+
+# These are string versions of all the errors defined in
+# nsILDAPErrors.idl, as well as the nsresult codes based on those
+# errors.  See that file for the genesis of these codes, as well as 
+# for info about how to get documentation about their precise
+# meanings.
+
+# These are string versions of all the errors defined in
+# nsILDAPErrors.idl, as well as the nsresult codes based on those
+# errors.  See that file for the genesis of these codes, as well as
+# for info about how to get documentation about their precise
+# meanings.
+
+## @name OPERATIONS_ERROR
+## @loc none
+1=Gwall gweithredu
+
+## @name PROTOCOL_ERROR
+## @loc none
+2=Gwall protocol
+
+## @name TIMELIMIT_EXCEEDED
+## @loc none
+3=Tu hwnt i derfyn amser
+
+## @name SIZELIMIT_EXCEEDED
+## @loc none
+4=Tu hwnt i derfyn maint
+
+## @name COMPARE_FALSE
+## @loc none
+5=Cymharu gau
+
+## @name COMPARE_TRUE
+## @loc none
+6=Cymharu true
+
+## @name STRONG_AUTH_NOT_SUPPORTED
+## @loc none
+7=Nid yw'r dull dilysu'n cael ei gynnal
+
+## @name STRONG_AUTH_REQUIRED
+## @loc none
+8=Mae angen dilysiad cryf
+
+## @name PARTIAL_RESULTS
+## @loc none
+9=Wedi derbyn canlyniadau a chyfeirio rhannol
+
+## @name REFERRAL
+## @loc none
+10=Cyfeirio wedi'i dderbyn
+
+## @name ADMINLIMIT_EXCEEDED
+## @loc none
+11=Terfyn gweinyddol wedi'i groesi
+
+## @name UNAVAILABLE_CRITICAL_EXTENSION
+## @loc none
+12=Estyniad hanfodol ddim ar gael
+
+## @name CONFIDENTIALITY_REQUIRED
+## @loc none
+13=Angen cyfrinachedd
+
+## @name SASL_BIND_IN_PROGRESS
+## @loc none
+14=Rhwymiad SASL ar waith
+
+## @name NO_SUCH_ATTRIBUTE
+## @loc none
+16=Dim priodoledd o'r fath
+
+## @name UNDEFINED_TYPE
+## @loc none
+17=Math priodoledd anniffinedig
+
+## @name INAPPROPRIATE MATCHIN
+## @loc none
+18=Cydweddu anaddas
+
+## @name CONSTRAINT_VIOLATION
+## @loc none
+19=Torri ar gyfyngiad
+
+## @name TYPE_OR_VALUE_EXISTS
+## @loc none
+20=Math neu werth ar gael
+
+## @name INVALID_SYNTAX
+## @loc none
+21=Cystrawen annilys
+
+## @name NO_SUCH_OBJECT
+## @loc none
+32=Dim gwrthrych o'r fath
+
+## @name ALIAS_PROBLEM
+## @loc none
+33=Problem enw arall
+
+## @name INVALID_DN_ SYNTAX
+## @loc none
+34=Cystrawen DN annilys
+
+## @name IS_LEAF
+## @loc none
+35=Mae'r gwrthrych yn ddeilen
+
+## @name ALIAS_DEREF_PROBLEM
+## @loc none
+36=Anhawster dadgyfeirio enw arall
+
+## @name INAPPROPRIATE_AUTH
+## @loc none
+48=Dilysiad annaddas
+
+## @name INVALID_CREDENTIALS
+## @loc none
+49=Cyflwyno annilys
+
+## @name INSUFFICIENT_ACCESS
+## @loc none
+50=Mynediad annigonol
+
+## @name BUSY
+## @loc none
+51=Mae'r gweinydd LDAP yn brysur
+
+## @name UNAVAILABLE
+## @loc none
+52=Nid yw'r gweinydd LDAP ar gael
+
+## @name UNWILLING_TO_PERFORM
+## @loc none
+53=Mae'r gweinydd LDAP yn gwrthod gweithredu
+
+## @name LOOP_DETECT
+## @loc none
+54=Cylchu wedi'i ganfod
+
+## @name SORT_CONTROL_MISSING
+## @loc none
+60=Mae Rheoli Didoli ar goll
+
+## @name INDEX_RANGE_ERROR
+## @loc none
+61=Mae canlyniadau chwilio'n fwy na'r ystod sydd wedi'i bennu gan yr atredau
+
+## @name NAMING_VIOLATION
+## @loc none
+64=Trosedd enwi
+
+## @name OBJECT_CLASS_VIOLATION
+## @loc none
+65=Trosedd dosbarth gwrthrych
+
+## @name NOT_ALLOWED_ON_NONLEAF
+## @loc none
+66=Dim caniatâd i'r weithred anddeilen
+
+## @name NOT_ALLOWED_ON_RDN
+## @loc none
+67=Dim caniatâd i'r weithred ar RDN
+
+## @name ALREADY_EXISTS
+## @loc none
+68=Yn bodoli eisoes
+
+## @name NO_OBJECT_CLASS_MODS
+## @loc none
+69=Methu newid dosbarth gwrthrych
+
+## @name RESULTS_TOO_LARGE
+## @loc none
+70=Canlyniad yn rhy fawr
+
+## @name AFFECTS_MULTIPLE_DSAS
+## @loc none
+71=Effeithio ar weinyddion niferus
+
+## @name OTHER
+## @loc none
+80=Gwall anhysbys
+
+## @name SERVER_DOWN
+## @loc none
+81=Methu cysylltu â gweinydd LDAP
+
+## @name LOCAL_ERROR
+## @loc none
+82=Gwall lleol
+
+## @name ENCODING_ERROR
+## @loc none
+83=Gwall amgodio
+
+## @name DECODING_ERROR
+## @loc none
+84=Gwall dadgodio
+
+## @name TIMEOUT
+## @loc none
+85=Daeth amser y gweinydd LDAP i ben
+
+## @name AUTH_UNKNOWN
+## @loc none
+86=Dull dilysu anhysbys
+
+## @name FILTER_ERROR
+## @loc none
+87=Hidl chwilio annilys
+
+## @name USER_CANCELLED
+## @loc none
+88=Gweithred defnyddiwr wedi'i ddiddymu
+
+## @name PARAM_ERROR
+## @loc none
+89=Paramedr gwael i drefn LDAP
+
+## @name NO_MEMORY
+## @loc none
+90=Dim cof ar ôl
+
+## @name CONNECT_ERROR
+## @loc none
+91=Methu cysylltu â weinydd LDAP
+
+## @name NOT_SUPPORTED
+## @loc none
+92=Nid yw'n cael ei gynnal gan y fersiwn yma o brotocol LDAP
+
+## @name CONTROL_NOT_FOUND
+## @loc none
+93=Heb ganfod y rheolydd LDAP
+
+## @name NO_RESULTS_RETURNED
+## @loc none
+94=Heb ddychwelyd canlyniadau
+
+## @name MORE_RESULTS_TO_RETURN
+## @loc none
+95=Rhagor o ganlyniadau i'w dychwelyd
+
+## @name CLIENT_LOOP
+## @loc none
+96=Mae'r cleient wedi canfod cylchu
+
+## @name REFERRAL_LIMIT_EXCEEDED
+## @loc none
+97=Hop cyfeirio wedi mynd dros y terfyn
diff --git a/l10n-cy/mail/chrome/overrides/netError.dtd b/l10n-cy/mail/chrome/overrides/netError.dtd
new file mode 100644
index 0000000000..c198ec17f6
--- /dev/null
+++ b/l10n-cy/mail/chrome/overrides/netError.dtd
@@ -0,0 +1,109 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
+%brandDTD;
+
+<!ENTITY loadError.label "Anhawster llwytho tudalen">
+<!ENTITY retry.label "Ceisio Eto">
+
+<!-- Specific error messages -->
+
+<!ENTITY connectionFailure.title "Methu cysylltu">
+<!ENTITY connectionFailure.longDesc "&sharedLongDesc;">
+
+<!ENTITY deniedPortAccess.title "Mae'r cyfeiriad wedi'i gyfyngu">
+<!ENTITY deniedPortAccess.longDesc "">
+
+<!ENTITY dnsNotFound.title "Heb ganfod gweinydd">
+<!ENTITY dnsNotFound.longDesc "<ul> <li>Gwiriwch y cyfeiriad am wallau teipio megis <strong>ww</strong>.example.com yn lle <strong>www</strong>.example.com</li> <li>Os ydych yn methu llwytho unrhyw dudalen, gwiriwch gysylltiad rhwydwaith eich cyfrifiadur.</li> <li>Os yw eich cyfrifiadur neu rwydwaith wedi ei ddiogelu gan fur cadarn neu ddirprwy gwnewch yn siŵr fod gan &brandShortName; ganiatâd i fynd ar y We.</li> </ul>">
+
+<!ENTITY fileNotFound.title "Heb ganfod ffeil">
+<!ENTITY fileNotFound.longDesc "<ul> <li>Gwiriwch yr enw ffeil am brif lythrennu neu wallau teipio eraill.</li> <li>Gwiriwch i weld os yw'r ffeil wedi symud, ailenwi neu ei dileu.</li> </ul>">
+
+<!ENTITY fileAccessDenied.title "Mae mynediad i'r ffeil wedi ei wrthod">
+<!ENTITY fileAccessDenied.longDesc "<ul> <li>Gall ei fod wedi ei dynnu, symud neu fod caniatâd ffeiliau yn rhwystro mynediad.</li> </ul>">
+
+<!ENTITY generic.title "Wps.">
+<!ENTITY generic.longDesc "<p>Nid yw &brandShortName; yn gallu llwytho'r dudalen am ryw reswm.</p>">
+
+<!ENTITY malformedURI.title "Nid yw'r cyfeiriad yn ddilys">
+<!ENTITY malformedURI.longDesc "<ul> <li>Fel rheol mae cyfeiriadau Gwe'n cael eu hysgrifennu fel <strong>http://www.example.com/</strong></li> <li>Gwnewch yn siŵr eich bod yn defnyddio blaen slaes (h.y. <strong>/</strong>).</li> </ul>">
+
+<!ENTITY netInterrupt.title "Cafodd y cysylltiad ei darfu">
+<!ENTITY netInterrupt.longDesc "&sharedLongDesc;">
+
+<!ENTITY notCached.title "Daeth y Ddogfen i Ben">
+<!ENTITY notCached.longDesc "<p>Nid yw'r ddogfen hon ar gael yn y storfa.</p><ul><li>Fel cam diogelwch nid yw, &brandShortName; yn gofyn eto am ddogfennau sensitif yn awtomatig.</li><li>Cliciwch Ceisio Eto i ofyn eto am y ddogfen o'r wefan.</li></ul>">
+
+<!ENTITY netOffline.title "Modd all-lein">
+<!ENTITY netOffline.longDesc2 "<ul> <li>Clicio &quot;Ceisio newid eto&quot; i newid i&apos;r modd ar-lein ac ail lwytho'r dudalen.</li> </ul>">
+
+<!ENTITY contentEncodingError.title "Gwall amgodio cynnwys">
+<!ENTITY contentEncodingError.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY unsafeContentType.title "Math ffeil anniogel">
+<!ENTITY unsafeContentType.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY netReset.title "Cafodd y cysylltiad ei ailosod">
+<!ENTITY netReset.longDesc "&sharedLongDesc;">
+
+<!ENTITY netTimeout.title "Mae cyfnod y cyswllt wedi dod i ben">
+<!ENTITY netTimeout.longDesc "&sharedLongDesc;">
+
+<!ENTITY unknownProtocolFound.title "Heb ddeall y cyfeiriad">
+<!ENTITY unknownProtocolFound.longDesc "<ul> <li>Efallai bydd angen i chi osod meddalwedd arall i agor y cyfeiriad yma.</li> </ul>">
+
+<!ENTITY proxyConnectFailure.title "Mae'r gweinydd dirprwy yn gwrthod cysylltiadau">
+<!ENTITY proxyConnectFailure.longDesc "<ul> <li>Gwiriwch osodiadau'r dirprwy i wneud yn siŵr eu bod yn gywir.</li> <li>Cysylltwch â'ch gweinyddwr system i wneud yn siŵr fod y gweinydd dirprwyol yn gweithio.</li> </ul>">
+
+<!ENTITY proxyResolveFailure.title "Methu canfod y gweinydd dirprwyol">
+<!ENTITY proxyResolveFailure.longDesc "<ul> <li>Gwiriwch y gosodiadau dirprwyol i wneud yn siŵr eu bod yn gywir.</li> <li>Gwiriwch fod gan eich cyfrifiadur cyswllt a'r we sy'n gweithio.</li> <li>Os yw eich cyfrifiadur wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan &brandShortName; fynediad i'r we.</li> </ul>">
+
+<!ENTITY redirectLoop.title "Nid yw'r dudalen yn ailgyfeirio'n iawn">
+<!ENTITY redirectLoop.longDesc "<ul> <li>Gall y broblem yma fod wedi ei hachosi drwy analluogi neu wrthod cwci.</li> </ul>">
+
+<!ENTITY unknownSocketType.title "Ymateb annisgwyl gan y gweinydd">
+<!ENTITY unknownSocketType.longDesc "<ul> <li>Gwiriwch fod gan eich system Reolwr Diogelwch Personol wedi ei osod.</li> <li>Gall hyn fod oherwydd ffurfweddiad ansafonol ar y gweinydd.</li> </ul>">
+
+<!ENTITY nssFailure2.title "Methodd y cysylltiad diogel">
+<!ENTITY nssFailure2.longDesc2 "<ul> <li>Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am nad oes modd dilysu'r data rydych wedi ei dderbyn.</li> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY nssBadCert.title "Methodd y cysylltiad diogel">
+<!ENTITY nssBadCert.longDesc2 "<ul> <li>Gall hwn fod yn anhawster gyda ffurfweddiad y gweinydd neu gall fod yn rhywun sy'n ceisio dynwared y gweinydd.</li> <li>Os ydych wedi cysylltu'n llwyddiannus gyda'r gweinydd yn y gorffennol, efallai mai gwall dros dro ydyw ac i geisio eto yn ddiweddarach.</li> </ul>">
+
+<!ENTITY sharedLongDesc "<ul> <li>Efallai bod y wefan yn brysur neu nad yw ar gael dros dro. Ceisiwch eto ymhen ychydig.</li> <li>Os nad ydych yn gallu llwytho unrhyw dudalennau, gwiriwch gysylltiad rhwydwaith eich cyfrifiadur.</li> <li>Os yw eich cyfrifiadur neu rwydwaith wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan &brandShortName; hawl i fynediad i'r we.</li> </ul>">
+
+<!ENTITY cspBlocked.title "Rhwystrwyd gan Bolisi Diogelwch Cynnwys">
+<!ENTITY cspBlocked.longDesc "<p>Mae &brandShortName; wedi rhwystro'r dudalen rhag llwytho yn y ffordd yma gan fod gan y dudalen bolisi diogelwch cynnwys sy'n atal hynny.</p>">
+
+<!ENTITY xfoBlocked.title "Wedi'i rwystro gan Bolisi X-Frame-Options">
+<!ENTITY xfoBlocked.longDesc "<p>Mae &brandShortName; wedi atal y dudalen hon rhag llwytho yn y cyd-destun hwn oherwydd bod gan y dudalen bolisi X-Frame-Options sy'n ei gwrthod.</p>">
+
+<!ENTITY corruptedContentErrorv2.title "Gwall Cynnwys Llygredig">
+<!ENTITY corruptedContentErrorv2.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio ei gweld yn sgil canfod gwall trosglwyddo data.</p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY securityOverride.linkText "Neu mae modd ychwanegu eithriad…">
+<!ENTITY securityOverride.getMeOutOfHereButton "Allan o fan hyn!">
+<!ENTITY securityOverride.exceptionButtonLabel "Ychwanegu Eithriad…">
+
+<!-- LOCALIZATION NOTE (securityOverride.warningContent) - Do not translate the
+contents of the <button> tags. It uses strings already defined above. The
+button is included here (instead of netError.xhtml) because it exposes
+functionality specific to thunderbird. -->
+
+<!ENTITY securityOverride.warningContent "<p>Ni ddylech ychwanegu eithriad os ydych yn defnyddio cyswllt gwe nad ydych yn ymddiried ynddo'n llwyr neu os nad ydych wedi arfer a gweld rhybudd ar y gweinydd hwn.</p>  <button id='getMeOutOfHereButton'>&securityOverride.getMeOutOfHereButton;</button> <button id='exceptionDialogButton'>&securityOverride.exceptionButtonLabel;</button>">
+
+<!ENTITY remoteXUL.title "XUL pell">
+<!ENTITY remoteXUL.longDesc "<p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu am y broblem..</li></ul></p>">
+
+<!ENTITY inadequateSecurityError.title "Nid yw eich cysylltiad yn ddiogel">
+<!-- LOCALIZATION NOTE (inadequateSecurityError.longDesc) - Do not translate
+     "NS_ERROR_NET_INADEQUATE_SECURITY". -->
+<!ENTITY inadequateSecurityError.longDesc "Mae <p><span class='hostname'></span> yn defnyddio technoleg diogelwch sy'n hen ac yn agored i ymosodiad. Gall yr ymosodwr weld manylion am hyn roeddech yn meddwl ei fod yn ddiogel. Mae angen i weinyddwr y wefan drwsio'r gweinydd yn gyntaf cyn bod modd i chi ymweld â' r wefan.</p><p>Cod gwall: NS_ERROR_NET_INADEQUATE_SECURITY</p>">
+
+<!ENTITY blockedByPolicy.title "Tudalen wedi ei Rhwystro">
+
+<!ENTITY networkProtocolError.title "Gwall Protocol Rhwydwaith">
+<!ENTITY networkProtocolError.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio'i gweld oherwydd canfuwyd gwall yn y protocol rhwydwaith.</p><ul><li>Cysylltwch â pherchenogion y wefan i roi gwybod iddynt am y broblem hon.</li></ul>">
diff --git a/l10n-cy/mail/chrome/overrides/profileDowngrade.dtd b/l10n-cy/mail/chrome/overrides/profileDowngrade.dtd
new file mode 100644
index 0000000000..11186f653d
--- /dev/null
+++ b/l10n-cy/mail/chrome/overrides/profileDowngrade.dtd
@@ -0,0 +1,20 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- LOCALIZATION NOTE:
+ This UI can be most easily shown by modifying the version in compatibility.ini
+ to a newer version and then starting Thunderbird.
+ For this feature, "installation" is used to mean "this discrete download of
+ Thunderbird" and "version" is used to mean "the specific revision number of a
+ given Thunderbird channel". These terms are not synonymous.
+-->
+<!ENTITY window.title "Rydych chi wedi cychwyn fersiwn hŷn o &brandProductName;">
+<!ENTITY window.style "width: 490px;">
+
+<!ENTITY window.nosync2 "Efallai fod fersiwn mwy diweddar o &brandProductName; wedi gwneud newidiadau i'ch proffil nad ydynt bellach yn gydnaws â'r fersiwn hŷn hwn. Defnyddiwch y proffil hwn yn unig gyda'r fersiwn mwy newydd hwnnw, neu crëwch broffil newydd ar gyfer y gosodiad hwn o &brandShortName;. Er mwyn creu proffil newydd mae angen gosod eich cyfrifon, calendrau a'ch ychwanegion eto.">
+
+<!ENTITY window.moreinfo "Rhagor o wybodaeth…">
+<!ENTITY window.create "Creu Proffil Newydd">
+<!ENTITY window.quit-win "Gadael">
+<!ENTITY window.quit-nonwin "Gadael">
diff --git a/l10n-cy/mail/chrome/overrides/settingsChange.dtd b/l10n-cy/mail/chrome/overrides/settingsChange.dtd
new file mode 100644
index 0000000000..d6c6303897
--- /dev/null
+++ b/l10n-cy/mail/chrome/overrides/settingsChange.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  settingsChangePreferences.label  "Mae modd newid y gosodiadau drwy ddefnyddio tab Atodiadau yn Dewisiadau &brandShortName;.">
+<!ENTITY  settingsChangeOptions.label      "Mae modd newid y gosodiadau drwy ddefnyddio tab Atodiadau yn Dewisiadau &brandShortName;.">
diff --git a/l10n-cy/mail/defines.inc b/l10n-cy/mail/defines.inc
new file mode 100644
index 0000000000..30a2380d7c
--- /dev/null
+++ b/l10n-cy/mail/defines.inc
@@ -0,0 +1,11 @@
+#filter emptyLines
+
+#define MOZ_LANGPACK_CREATOR mozilla.org
+
+# If non-English locales wish to credit multiple contributors, uncomment this
+
+# variable definition and use the format specified.
+
+#define MOZ_LANGPACK_CONTRIBUTORS <em:contributor>Rhoslyn Prys</em:contributor>
+
+#unfilter emptyLines
diff --git a/l10n-cy/mail/installer/custom.properties b/l10n-cy/mail/installer/custom.properties
new file mode 100644
index 0000000000..44013414d9
--- /dev/null
+++ b/l10n-cy/mail/installer/custom.properties
@@ -0,0 +1,85 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+REG_APP_DESC=Mae $BrandShortName yn rhaglen e-bost cynhwysfawr. Mae $BrandShortName yn cynnal protocolau e-bost IMAP a POP, yn ogystal a gallu fformatio e-bost gydag HTML. O'i fewn mae rheolau sbam, gallu RSS, chwilio cyflym pwerus, gwirio sillafu wrth i chi deipio, blwch derbyn eang, ac mae hidlo negeseuon soffistigedig yn crynhoi set nodweddion cyfoes $BrandShortName.
+CONTEXT_OPTIONS=&Dewisiadau $BrandShortName
+CONTEXT_SAFE_MODE=&Modd Diogel $BrandShortName
+OPTIONS_PAGE_TITLE=Math o Osod
+OPTIONS_PAGE_SUBTITLE=Dewisiadau gosod
+SHORTCUTS_PAGE_TITLE=Llwybrau Byr y Gosod
+SHORTCUTS_PAGE_SUBTITLE=Creu Eiconau'r Rhaglen
+COMPONENTS_PAGE_TITLE=Gosod Cydrannau Ychwanegol
+COMPONENTS_PAGE_SUBTITLE=Cydrannau Dewisol Cymeradwy
+OPTIONAL_COMPONENTS_DESC=Bydd y Gwasanaeth Cynnal yn caniatáu i chi ddiweddaru $BrandShortName yn dawel yn y cefndir.
+MAINTENANCE_SERVICE_CHECKBOX_DESC=&Gosod y Gwasanaeth Cynnal
+SUMMARY_PAGE_TITLE=Crynodeb
+SUMMARY_PAGE_SUBTITLE=Yn barod i osod $BrandShortName
+SUMMARY_INSTALLED_TO=Bydd $BrandShortName yn cael ei osod yn y lleoliad canlynol:
+SUMMARY_REBOOT_REQUIRED_INSTALL=Efallai bydd angen ailgychwyn y cyfrifiadur er mwyn cwblhau'r gosod.
+SUMMARY_REBOOT_REQUIRED_UNINSTALL=Efallai bydd angen ailgychwyn y cyfrifiadur er mwyn cwblhau'r dadosod.
+SUMMARY_TAKE_DEFAULTS=Defnyddio $BrandShortName fel fy rhaglen e-bost rhagosodedig
+SUMMARY_INSTALL_CLICK=Clicio Gosod i barhau.
+SUMMARY_UPGRADE_CLICK=Clicio Diweddaru i barhau.
+SURVEY_TEXT=&Dweud wrthym eich barn am $BrandShortName
+LAUNCH_TEXT=&Cychwyn $BrandFullName nawr
+CREATE_ICONS_DESC=Creu eiconau $BrandShortName:
+ICONS_DESKTOP=&Ar y Bwrdd Gwaith
+ICONS_STARTMENU=&Yn ffolder Rhaglenni Dewislen Cychwyn
+ICONS_QUICKLAUNCH=&Yn y bar Cychwyn Cyflym
+WARN_MANUALLY_CLOSE_APP_INSTALL=Rhaid cau $BrandShortName er mwyn parhau gyda'r gosod.\n\nCaewch $BrandShortName er mwyn parhau.
+WARN_MANUALLY_CLOSE_APP_UNINSTALL=Rhaid cau $BrandShortName er mwyn parhau gyda'r dadosod.\n\nCaewch $BrandShortName er mwyn parhau.
+WARN_MANUALLY_CLOSE_APP_LAUNCH=Mae $BrandShortName yn rhedeg yn barod.\n\nCaewch $BrandShortName cyn cychwyn y fersiwn rydych newydd ei osod.
+WARN_WRITE_ACCESS=Nid oes gennych fynediad i ysgrifennu i'r cyfeiriadur gosod.\n\nCliciwch Iawn i ddewis cyfeiriadur gwahanol.
+WARN_DISK_SPACE=Nid oes gennych ddigon o le ar ddisg i osod yn y lleoliad hwn.\n\nCliciwch Iawn i ddewis lleoliad gwahanol.
+WARN_MIN_SUPPORTED_OSVER_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} neu fwy diweddar. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen prosesydd gyda chefnogaeth ar gyfer ${MinSupportedCPU}. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_MIN_SUPPORTED_OSVER_CPU_MSG=Ymddiheuriadau, nid oes modd gosod $BrandShortName. Mae'r fersiwn hwn o $BrandShortName angen ${MinSupportedVer} a phrosesydd gyda chefnogaeth ar gyfer ${MinSupportedCPU}. Cliciwch ar y botwm Iawn am wybodaeth bellach.
+WARN_RESTART_REQUIRED_UNINSTALL=Rhaid ailgychwyn y cyfrifiadur er mwyn cwblhau dadosod y fersiwn diwethaf o $BrandShortName. Hoffech chi ailgychwyn nawr?
+WARN_RESTART_REQUIRED_UPGRADE=Rhaid ailgychwyn y cyfrifiadur er mwyn cwblhau'r diweddariad diwethaf o $BrandShortName. Hoffech chi ailgychwyn nawr?
+ERROR_CREATE_DIRECTORY_PREFIX=Gwall wrth greu cyfeiriadur:
+ERROR_CREATE_DIRECTORY_SUFFIX=Cliciwch Diddymu i atal gosod neu\nEto er mwyn ceisio eto.
+
+UN_CONFIRM_PAGE_TITLE=Dad-osod $BrandFullName
+UN_CONFIRM_PAGE_SUBTITLE=Tynnu $BrandFullName oddi ar eich cyfrifiadur.
+UN_CONFIRM_UNINSTALLED_FROM=Bydd $BrandShortName yn cael ei ddadosod o'r lleoliad canlynol:
+UN_CONFIRM_CLICK=Cliciwch Dadosod i barhau.
+
+BANNER_CHECK_EXISTING=Gwirio'r gosodiad presennol…
+
+STATUS_INSTALL_APP=Gosod $BrandShortName…
+STATUS_INSTALL_LANG=Gosod Ffeiliau Iaith (${AB_CD})…
+STATUS_UNINSTALL_MAIN=Dadosod $BrandShortName…
+STATUS_CLEANUP=Glanhau…
+
+# _DESC strings support approximately 65 characters per line.
+# One line
+OPTIONS_SUMMARY=Dewis y math o osod sydd orau gennych, yna clicio Nesaf.
+# One line
+OPTION_STANDARD_DESC=Bydd $BrandShortName yn cael ei osod gyda'r dewisiadau mwyaf cyffredin.
+OPTION_STANDARD_RADIO=&Safonol
+# Two lines
+OPTION_CUSTOM_DESC=Gallwch ddewis dewisiadau unigol i'w gosod. Ar gyfer defnyddwyr uwch.
+OPTION_CUSTOM_RADIO=&Cyfaddasu
+
+# LOCALIZATION NOTE:
+# The following text replaces the Install button text on the summary page.
+# Verify that the access key for InstallBtn (in override.properties) and
+# UPGRADE_BUTTON is not already used by SUMMARY_TAKE_DEFAULTS.
+UPGRADE_BUTTON=&Diweddaru
diff --git a/l10n-cy/mail/installer/mui.properties b/l10n-cy/mail/installer/mui.properties
new file mode 100644
index 0000000000..afb3b13d1c
--- /dev/null
+++ b/l10n-cy/mail/installer/mui.properties
@@ -0,0 +1,60 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# To make the l10n tinderboxen see changes to this file you can change a value
+# name by adding - to the end of the name followed by chars (e.g. Branding-2).
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+MUI_TEXT_WELCOME_INFO_TITLE=Croeso i Ddewin Gosod $BrandFullNameDA
+MUI_TEXT_WELCOME_INFO_TEXT=Bydd y dewin yn eich tywys wrth osod $BrandFullNameDA.\n\nArgymhellir eich bod yn cau pob rhaglen arall cyn cychwyn gosod. Bydd hyn yn ei gwneud yn bosibl i ddiweddaru'r ffeiliau system berthnasol heb fod angen ailgychwyn eich cyfrifiadur.\n\n$_CLICK
+MUI_TEXT_COMPONENTS_TITLE=Dewis Cydrannau
+MUI_TEXT_COMPONENTS_SUBTITLE=Dewiswch pa nodweddion $BrandFullNameDA rydych am eu gosod.
+MUI_INNERTEXT_COMPONENTS_DESCRIPTION_TITLE=Disgrifiad
+MUI_INNERTEXT_COMPONENTS_DESCRIPTION_INFO=Rhowch eich llygoden ar draws cydran i weld ei ddisgrifiad.
+MUI_TEXT_DIRECTORY_TITLE=Dewis Lleoliad Gosod
+MUI_TEXT_DIRECTORY_SUBTITLE=Dewiswch y ffolder lle mae gosod $BrandFullNameDA.
+MUI_TEXT_INSTALLING_TITLE=Gosod
+MUI_TEXT_INSTALLING_SUBTITLE=Arhoswch tra bod $BrandFullNameDA yn cael ei osod.
+MUI_TEXT_FINISH_TITLE=Wedi Cwblhau Gosod
+MUI_TEXT_FINISH_SUBTITLE=Gosod wedi'i gwblhau'n llwyddiannus.
+MUI_TEXT_ABORT_TITLE=Atalwyd y Gosod
+MUI_TEXT_ABORT_SUBTITLE=Ni chwblhawyd y gosod yn llwyddiannus.
+MUI_BUTTONTEXT_FINISH=&Gorffen
+MUI_TEXT_FINISH_INFO_TITLE=Cwblhau Dewin Gosod $BrandFullNameDA
+MUI_TEXT_FINISH_INFO_TEXT=Mae $BrandFullNameDA. wedi'i osod ar eich cyfrifiadur.\n\nCliciwch Gorffen i gau'r dewin.
+MUI_TEXT_FINISH_INFO_REBOOT=Rhaid ailgychwyn eich cyfrifiadur er mwyn cwblhau gosod $BrandFullNameDA. Hoffech chi wneud hynny?
+MUI_TEXT_FINISH_REBOOTNOW=Ail gychwyn nawr
+MUI_TEXT_FINISH_REBOOTLATER=Rwyf am ailgychwyn yn hwyrach
+MUI_TEXT_STARTMENU_TITLE=Dewis Ffolder Dewislen Cychwyn
+MUI_TEXT_STARTMENU_SUBTITLE=Dewiswch ffolder Dewislen Cychwyn ar gyfer llwybrau byr $BrandFullNameDA.
+MUI_INNERTEXT_STARTMENU_TOP=Dewiswch ffolder Dewislen Cychwyn lle'r hoffech greu llwybrau byr y rhaglen. Gallwch osod enw i'r ffolder newydd.
+MUI_TEXT_ABORTWARNING=Ydych chi'n siŵr eich bod am adael Gosod $BrandFullName?
+MUI_UNTEXT_WELCOME_INFO_TITLE=Croeso i Ddewin Dadosod $BrandFullNameDA
+MUI_UNTEXT_WELCOME_INFO_TEXT=Bydd y dewin yn eich tywys drwy ddadosod $BrandFullNameDA.\n\nCyn cychwyn dadosod gwnewch yn siwr nad yw $BrandFullNameDA yn rhedeg.\n\n$_CLICK
+MUI_UNTEXT_CONFIRM_TITLE=Dadosod $BrandFullNameDA
+MUI_UNTEXT_CONFIRM_SUBTITLE=Tynnu $BrandFullNameDA oddi ar eich cyfrifiadur.
+MUI_UNTEXT_UNINSTALLING_TITLE=Dadosod
+MUI_UNTEXT_UNINSTALLING_SUBTITLE=Arhoswch tra bo $BrandFullNameDA yn cael ei dadosod.
+MUI_UNTEXT_FINISH_TITLE=Dadosod wedi'i gwblhau
+MUI_UNTEXT_FINISH_SUBTITLE=Dadosod wedi'i gwblhau'n llwyddiannus.
+MUI_UNTEXT_ABORT_TITLE=Atal y Dadosod
+MUI_UNTEXT_ABORT_SUBTITLE=Ni chwyblhawyd y dadosod yn llwyddiannus.
+MUI_UNTEXT_FINISH_INFO_TITLE=Cwblhau Dewin Dadosod $BrandFullNameDA
+MUI_UNTEXT_FINISH_INFO_TEXT=Mae $BrandFullNameDA wedi'i dadosod o'ch cyfrifiadur.\n\nCliciwch Gorffen i gau'r dewin.
+MUI_UNTEXT_FINISH_INFO_REBOOT=Rhaid ailgychwyn eich cyfrifiadur er mwyn cwblhau dadosod $BrandFullNameDA. Hoffech chi ailgychwyn?
+MUI_UNTEXT_ABORTWARNING=Ydych chi'n siwr eich bod am adael dadosod $BrandFullName Uninstall?
diff --git a/l10n-cy/mail/installer/override.properties b/l10n-cy/mail/installer/override.properties
new file mode 100644
index 0000000000..dd70aa14f2
--- /dev/null
+++ b/l10n-cy/mail/installer/override.properties
@@ -0,0 +1,86 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE:
+
+# This file must be saved as UTF8
+
+# Accesskeys are defined by prefixing the letter that is to be used for the
+# accesskey with an ampersand (e.g. &).
+
+# Do not replace $BrandShortName, $BrandFullName, or $BrandFullNameDA with a
+# custom string and always use the same one as used by the en-US files.
+# $BrandFullNameDA allows the string to contain an ampersand (e.g. DA stands
+# for double ampersand) and prevents the letter following the ampersand from
+# being used as an accesskey.
+
+# You can use \n to create a newline in the string but only when the string
+# from en-US contains a \n.
+
+# Strings that require a space at the end should be enclosed with double
+# quotes and the double quotes will be removed. To add quotes to the beginning
+# and end of a string enclose the strin with an additional double quote
+# (e.g. ""This will include quotes"").
+
+SetupCaption=Gosod $BrandFullName
+UninstallCaption=Dadosod $BrandFullName
+BackBtn=< &Nôl
+NextBtn=&Nesaf >
+AcceptBtn=&Rwy'n derbyn amodau'r Cytundeb Trwyddedu
+DontAcceptBtn=&Nid wyf yn derbyn amodau'r Cytundeb Trwyddedu
+InstallBtn=&Gosod
+UninstallBtn=&Dadosod
+CancelBtn=Diddymu
+CloseBtn=&Cau
+BrowseBtn=&Pori…
+ShowDetailsBtn=&Dangos manylion
+ClickNext=Cliciwch Nesaf i barhau.
+ClickInstall=Cliciwch Gosod i gychwyn gosod.
+ClickUninstall=Cliciwch Dadosod i gychwyn dadosod.
+Completed=Cwblhawyd
+LicenseTextRB=Darllenwch y cytundeb trwyddedu cyn gosod $BrandFullNameDA. Os ydych yn derbyn amodau’r cytundeb, dewiswch y dewis cyntaf isod. $_CLICK
+ComponentsText=Ticiwch y cydrannau rydych am eu gosod a dad dicio'r cydrannau nad ydych am eu gosod. $_CLICK
+ComponentsSubText2_NoInstTypes=Dewiswch gydrannau i'w gosod:
+DirText=Bydd y gosod yn gosod $BrandFullNameDA yn y ffolder canlynol. I'w osod mewn ffolder gwahanol, cliciwch Pori a dewis ffolder arall. $_CLICK
+DirSubText=Ffolder Cyrchfan
+DirBrowseText=Dewiswch y ffolder i osod $BrandFullNameDA ynddi:
+SpaceAvailable="Lle ar gael: "
+SpaceRequired="Lle angenrheidiol: "
+UninstallingText=Bydd $BrandFullNameDA yn cael ei ddadosod o'r ffolder canlynol. $_CLICK
+UninstallingSubText=Dadosod o:
+FileError=Gwall wrth agor ffeil i'w ysgrifennu: \r\n\r\n$0\r\n\r\nCiciwch Atal i atal y gosod,\r\nAil-geisio i geisio eto neu\r\nAnwybyddu i hepgor y ffeil.
+FileError_NoIgnore=Gwall wrth agor ffeil i'w ysgrifennu: \r\n\r\n$0\r\n\r\nAil-geisio i geisio eto neu\r\nDiddymu i atal y gosod.
+CantWrite="Methu ysgrifennu: "
+CopyFailed=Methodd copïo
+CopyTo="Copïo i "
+Registering="Cofrestru: "
+Unregistering="Dadgofrestru: "
+SymbolNotFound="Methu canfod symbol: "
+CouldNotLoad="Methu llwytho: "
+CreateFolder="Creu ffolder: "
+CreateShortcut="Creu llwybr byr: "
+CreatedUninstaller="Creu dadosodwr: "
+Delete="Dileu ffeil: "
+DeleteOnReboot="Dileu wrth ailgychwyn: "
+ErrorCreatingShortcut="Gwall wrth greu llwybr byr: "
+ErrorCreating="Creu gwall: "
+ErrorDecompressing=Gwall wrth ddatgywasgu data! Gosodwr llwgr?
+ErrorRegistering=Gwall cofrestru DLL
+ExecShell="ExecShell: "
+Exec="Gweithredu: "
+Extract="Echdynnu: "
+ErrorWriting="Echdynnu: gwall ysgrifennu i ffeil "
+InvalidOpcode=Gosodwr gwallus: opcode annilys
+NoOLE="Dim OLE ar gyfer: "
+OutputFolder="Ffolder allbwn: "
+RemoveFolder="Tynnu Ffolder: "
+RenameOnReboot="Ailenwi wrth ailgychwyn: "
+Rename="Ailenwi: "
+Skipped="Hepgorwyd: "
+CopyDetails=Copïo Manylion i'r Clipfwrdd
+LogInstall=Cofnodi'r broses osod
+Byte=B
+Kilo=K
+Mega=M
+Giga=G
diff --git a/l10n-cy/mail/messenger/aboutProfilesExtra.ftl b/l10n-cy/mail/messenger/aboutProfilesExtra.ftl
new file mode 100644
index 0000000000..365a877011
--- /dev/null
+++ b/l10n-cy/mail/messenger/aboutProfilesExtra.ftl
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+profiles-launch-profile-plain = Agor proffil
diff --git a/l10n-cy/mail/messenger/aboutRights.ftl b/l10n-cy/mail/messenger/aboutRights.ftl
new file mode 100644
index 0000000000..c6e615e355
--- /dev/null
+++ b/l10n-cy/mail/messenger/aboutRights.ftl
@@ -0,0 +1,30 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+rights-title = Ynghylch eich hawliau
+rights-intro = Mae { -brand-full-name } yn feddalwedd cod agored rhydd a rhad, wedi ei adeiladu gan gymuned o filoedd o bobl ar draws y byd i gyd. Mae yna rhai pethau i chi gael gwybod:
+rights-intro-point-1 = Mae { -brand-short-name } ar gael i chi o dan amodau'r <a data-l10n-name="mozilla-public-license-link">Trwydded Gyhoeddus Mozilla</a>. Mae hyn yn golygu y cewch ddefnyddio, gopïo a dosbarthu { -brand-short-name } i eraill.  Mae croeso i chi newid cod ffynhonnell { -brand-short-name } yn ôl eich angen. Mae Trwydded Gyhoeddus Mozilla yn rhoi'r hawl i chi ddosbarthu'r fersiwn rydych wedi ei newid.
+rights-intro-point-2 = Nid ydych yn derbyn unrhyw hawliau nod masnachu na thrwyddedau i nod masnach y Mozilla Foundation neu unrhyw barti, gan gynnwys heb gyfyngiadau i enw na logo Thunderbird . Mae gwybodaeth bellach am nodau masnach i’w cael <a data-l10n-name="mozilla-trademarks-link">yma</a>.
+rights-intro-point-3 = Mae rhai nodweddion yn { -brand-short-name }, megis yr Adroddwr Chwalu, yn rhoi'r dewis i chi gyfrannu adborth i { -vendor-short-name }. Drwy ddewis cyflwyno adborth rydych yn rhoi i { -vendor-short-name } ganiatâd i ddefnyddio'r adborth i wella ei gynnyrch, i gyhoeddi'r adborth ar ei wefannau, ac i ddosbarthu'r adborth.
+rights-intro-point-4 = Mae sut rydym yn defnyddio y data personol ac adborth rydych wedi ei gyflwyno i { -vendor-short-name } drwy { -brand-short-name } yn cael ei ddisgrifio yn <a data-l10n-name="mozilla-privacy-policy-link">Polisi Preifatrwydd { -brand-short-name }</a>.
+rights-intro-point-4-unbranded = Rhaid rhestri unrhyw bolisïau preifatrwydd perthnasol yma.
+rights-intro-point-5 = Mae rhai nodweddion { -brand-short-name } yn gwneud defnydd p wasanaethau gwybodaeth gwe, er hynny nid ydym yn gallu gwarantu eu bod yn 100% yn gywir nac yn rhydd o wallau. Mae rhagor o fanylion, gan gynnwys gwybodaeth ar sut i'w hanalluogi i'w cael yn yr <a data-l10n-name="mozilla-service-terms-link">amodau gwasanaeth</a>.
+rights-intro-point-5-unbranded = Os yw'r cynnyrch yn cynnwys gwasanaethau gwe, rhaid cysylltu unrhyw amodau gwasanaeth perthnasol ar gyfer y gwasanaeth(au) i'r adran <a data-l10n-name="mozilla-website-services-link">Gwasanaethau Gwefan</a> Gwe.
+rights-intro-point-6 = Er mwyn chwarae rhai mathau o gynnwys fideo, mae { -brand-short-name } yn llwytho i lawr rhywfaint o gynnwys modiwlau dadgryptio gan drydydd partïon.
+rights-webservices-header = Gwasanaethau Gwybodaeth Gwe { -brand-full-name }
+rights-webservices = Mae { -brand-full-name } yn defnyddio gwasanaethau gwybodaeth gwe ("Gwasanaethau") i ddarparu rhai o'r nodweddion sy'n cael eu darparu ar eich cyfer yn y fersiwn yma o { -brand-short-name } o fewn yr amodau disgrifir isod. Os nad ydych am ddefnyddio un neu fwy o'r Gwasanaethau neu mae'r amodau yn annerbyniol, mae modd i chi analluogi'r nodwedd neu'r Gwasanaeth(au). Mae gwybodaeth ar sut i analluogi nodwedd neu Wasanaeth penodol i'w cael <a data-l10n-name="mozilla-disable-service-link">yma</a>. Mae modd analluogi nodweddion a Gwasanaethau eraill yn newisiadau'r rhaglen.
+rights-locationawarebrowsing = <strong>Pori Ymwybodol o Leoliad: </strong>yn ddewis i chi bob tro.  Ni fydd gwybodaeth yn cael ei anfon heb eich caniatâd.  Os hoffech chi analluogi'r nodwedd yn llwyr, dilynwch y camau hyn:
+rights-locationawarebrowsing-term-1 = Yn y bar URL, teipiwch <code>about:config</code>
+rights-locationawarebrowsing-term-2 = Teipio geo.enabled
+rights-locationawarebrowsing-term-3 = Clic dwbl i'r dewis geo.enabled
+rights-locationawarebrowsing-term-4 = Mae Pori Ymwybodol o Leoliad wedi ei analluogi
+rights-webservices-unbranded = Rhaid cynnwys yn fan hyn, drosolwg o'r gwasanaeth gwefan gwe mae'r cynnyrch yn ei gynnwys, ynghyd â chyfarwyddiadau ar sut i'w hatal os yn berthnasol.
+rights-webservices-term-unbranded = Rhaid rhestru amodau gwasanaethau gwe yma.
+rights-webservices-term-1 = Mae { -vendor-short-name } a'i gyfranwyr, trwyddedwyr, a phartneriaid yn gweithio i ddarparu'r Gwasanaethau mwyaf cywir a chyfredol.  Er hynny, nid oes modd i ni warantu fod y wybodaeth yn gynhwysfawr a diwall.  Er enghraifft, efallai na fydd y Gwasanaeth Pori Diogel yn adnabod rhai gwefannau anniogel ac efallai adnabod rhai gwefannau diogel ar gam. Mae pob lleoliad sy'n cael ei ddychwelyd gan ein darparwyr gwasanaeth ar gyfer y Gwasanaeth Ymwybodol o Leoliad yn amcanion yn unig. Nid ydym ni na'r darparwyr gwasanaeth yn gallu gwarantu cywirdeb y lleoliadau hyn.
+rights-webservices-term-2 = Gall { -vendor-short-name } atal neu newid y Gwasanaethau yn ôl eu mympwy.
+rights-webservices-term-3 = Mae croeso i chi ddefnyddio'r Gwasanaethau hyn gyda'r fersiwn yma o { -brand-short-name }, ac mae { -vendor-short-name } rhoi ei hawl i chi wneud hynny.  Mae { -vendor-short-name } a'i drwyddedwyr yn diogelu pob hawl arall yn y Gwasanaethau.  Nid yw'r amodau wedi eu hanelu at gyfyngu unrhyw hawliau o dan drwyddedau cod agored sy'n perthyn i { -brand-short-name } ac i'r fersiynau perthnasol o ffynonellau cod { -brand-short-name }.
+rights-webservices-term-4 = <strong>Mae'r gwasanaeth yn cael ei ddarparu "fel ag y mae".  Mae { -vendor-short-name }, ei gyfranwyr, trwyddedwyr, a dosbarthwyr, yn gwadu unrhyw warant, p'un ai yn cael ei fynegi neu ei awgrymu, gan gynnwys heb gyfyngiad, gwarant fod y Gwasanaethau yn farchnadadwy nac yn addas i'ch pwrpas penodol.  Rydych yn derbyn yr holl risg o ddewis y Gwasanaethau ar gyfer eich pwrpas ac i natur ansawdd a pherfformiad y Gwasanaeth. Nid yw rhai awdurdodau'n caniatáu eithrio neu gyfyngu gwarant sy'n cael ei awgrymu felly efallai nad yw'r gwadiad hwn yn berthnasol i chi.</strong>
+rights-webservices-term-5 = <strong>Yn wahanol i'r hyn sy'n angenrheidiol yn ôl y gyfraith, ni fydd { -vendor-short-name }, ei gyfranwyr, trwyddedwyr a dosbarthwyr yn agored i unrhyw iawndal anuniongyrchol, arbenigol, achlysurol, neu enghreifftiol yn codi o neu mewn unrhyw ffordd yn berthnasol i'r defnydd o { -brand-short-name } a'r Gwasanaethau.   Ni fydd yr atebolrwydd cyfunol o dan yr amodau hyn yn fwy na $500 (pum can dollar). Nid yw rhai awdurdodau yn caniatáu cyfyngu ar rhai materion difrod, felly efallai na fydd hyn yn berthnasol i chi.</strong>
+rights-webservices-term-6 = Gall { -vendor-short-name } ddiweddaru'r amodau yn ôl y galw o bryd i'w gilydd. Nid oes modd newid na dileu'r amodau heb ganiatâd ysgrifenedig { -vendor-short-name }.
+rights-webservices-term-7 = Mae'r amodau yn cael eu rheoli gan gyfreithiau talaith California, UDA, gan hepgor ei ddarpariaethau gwrthdaro cyfreithiol. Os yw unrhyw ran o'r amodau i'w cael heb rym cyfreithiol byd y gweddill yn sefyll mewn grym llawn ac effaith. Os digwydd gwrthdaro rhwng fersiwn sydd wedi ei gyfieithu a'r amodau hyn a'r fersiwn Saesneg, y fersiwn Saesneg fydd yn rheoli.
diff --git a/l10n-cy/mail/messenger/aboutSupportMail.ftl b/l10n-cy/mail/messenger/aboutSupportMail.ftl
new file mode 100644
index 0000000000..48d2f089be
--- /dev/null
+++ b/l10n-cy/mail/messenger/aboutSupportMail.ftl
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+accounts-title = Cyfrifon E-bost a Newyddion
+show-private-data-main-text = Cynnwys enwau cyfrifon
+show-private-data-explanation-text = (manylion adnabod personol posib)
+accounts-ID = ID
+accounts-name = Enw
+accounts-incoming-server = Gweinydd Derbyn
+accounts-outgoing-servers = Gweinydd Allan
+accounts-server-name = Enw
+accounts-conn-security = Diogelwch cysylltiad
+accounts-auth-method = Dull dilysu
+accounts-default = Rhagosodiad?
+identity-name = hunaniaeth
+
+send-via-email = Anfon drwy e-bost
+
+app-basics-telemetry = Data Telemetreg
diff --git a/l10n-cy/mail/messenger/accountCentral.ftl b/l10n-cy/mail/messenger/accountCentral.ftl
new file mode 100644
index 0000000000..ae81e32c0c
--- /dev/null
+++ b/l10n-cy/mail/messenger/accountCentral.ftl
@@ -0,0 +1,68 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+account-central-title = Croeso i { -brand-full-name }
+account-settings = Gosodiadau Cyfrif
+
+#   $accounts (Number) - the number of configured accounts
+setup-title = Dewis Beth i'w Osod
+about-title = Ynghylch { -brand-full-name }
+resources-title = Adnoddau
+
+release-notes =
+    .title = Ynghylch { -brand-full-name }
+
+email-label = E-bost
+    .aria-label = Cysylltu i'ch cyfeiriad e-bost cyfredol
+email-description = Mae { -brand-short-name } yn galluogi chi gysylltu â'ch cyfrif e-bost presennol, i ddarllen eich e-byst yn gyfleus ac yn effeithlon o fewn y rhaglen.
+
+calendar-label = Calendr
+    .aria-label = Creu calendr newydd
+calendar-description = Mae { -brand-short-name } yn galluogi i chi drin digwyddiadau a chadw trefn. Bydd cysylltu â chalendr pell yn cydweddu'ch holl ddigwyddiadau ar draws eich holl ddyfeisiau.
+
+chat-label = Sgwrs
+    .aria-label = Cysylltu â'ch cyfrif sgwrsio
+chat-description = Mae { -brand-short-name } yn galluogi i chi gysylltu â sawl cyfrif negeseua chwim, gan gynnig cefnogaeth i nifer o lwyfannau amrywiol.
+
+filelink-label = Filelink
+    .aria-label = Gosod Filelink
+filelink-description = Mae { -brand-short-name } yn galluogi i chi greu cyfrif Filelink cwmwl cyfleus i anfon atodiadau mawr yn hawdd.
+
+addressbook-label = Llyfr Cyfeiriadau
+    .aria-label = Creu llyfr cyfeiriadau newydd
+addressbook-description = Mae { -brand-short-name } yn galluogi i chi drefnu'ch holl gysylltiadau mewn llyfr cyfeiriadau. Gallwch hefyd gysylltu â llyfr cyfeiriadau o bell i gydweddu'ch holl gysylltiadau.
+
+feeds-label = Llif
+    .aria-label = Cysylltu â llifau
+feeds-description = Mae { -brand-short-name } yn galluogi i chi gysylltu â phorthwyr RSS / Atom i gael newyddion a diweddariadau o bob man.
+
+newsgroups-label = Grwpiau Newyddion
+    .aria-label = Cysylltu â grŵp newyddion
+newsgroups-description = Mae { -brand-short-name } yn galluogi i chi gysylltu â'r holl grwpiau newyddion yr hoffech chi
+
+import-title = Mewnforio o Raglen Arall
+import-paragraph = Mae { -brand-short-name } yn galluogi i chi fewnforio negeseuon e-bost, cofnodion llyfr cyfeiriadau, tanysgrifiadau llif, dewisiadau, a/neu hidlwyr o raglenni e-bost eraill a fformatau llyfrau cyfeiriadau cyffredin.
+
+import-label = Mewnforio
+    .aria-label = Mewnforio data o raglenni eraill
+
+about-paragraph = Mae Thunderbird yw'r prif raglen e-bost a chalendr, croes blatfform, cod agored, sydd ar gael am ddim ar gyfer defnydd busnes neu bersonol. Rydym am barhau i'w gadw'n ddiogel ac i'w wella i'r dyfodol. Bydd cyfraniad yn caniatáu i ni gyflogi datblygwyr, talu am isadeiledd a pharhau i'w wella.
+
+about-paragraph-2 = Mae <b>Thunderbird yn cael ei ariannu gan ddefnyddwyr fel chi! Os ydych chi'n hoff o Thunderbird, ystyriwch roi rhodd.</b> Y ffordd orau i chi sicrhau bod Thunderbird yn parhau i fod ar gael yw i
+about-donation = wneud rhodd
+
+about-paragraph-consider-donation = <b>Mae Thunderbird yn cael ei ariannu gan ddefnyddwyr fel chi! Os ydych chi'n hoffi Thunderbird, ystyriwch wneud rhodd.</b> Y ffordd orau i wneud yn siŵr fod Thunderbird yn parhau i fod ar gael yw <a data-l10n-name="donation-link"> i wneud cyfraniad.</a>
+
+explore-link = Edrych ar y Nodweddion
+support-link = Cefnogaeth
+involved-link = Ymunwch â ni!
+developer-link = Dogfennaeth Datblygwr
+
+read = Darllen negeseuon
+compose = Ysgrifennu neges newydd
+search = Chwilio drwy'r Negeseuon
+filter = Rheoli hidlau negeseuon
+nntp-subscription = Rheoli tanysgrifiadau grwpiau newyddion
+rss-subscription = Rheoli tanysgrifiadau llif
+e2e = Amgryptio Pen-i-Ben
diff --git a/l10n-cy/mail/messenger/addressbook/abCardDAVDialog.ftl b/l10n-cy/mail/messenger/addressbook/abCardDAVDialog.ftl
new file mode 100644
index 0000000000..c4ceb5bbdf
--- /dev/null
+++ b/l10n-cy/mail/messenger/addressbook/abCardDAVDialog.ftl
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+carddav-window =
+    .title = Llyfr Cyfeiriadau CardDAV newydd
+
+carddav-dialog =
+    .buttonlabelaccept = Parhau
+    .buttonaccesskeyaccept = P
+
+carddav-experimental-warning = Mae cefnogaeth llyfr cyfeiriadau CardDAV yn arbrofol a gallai niweidio'ch data yn barhaol. Defnyddiwch ar eich risg eich hun.
+
+carddav-provider-label =
+    .value = Darparwr CardDAV:
+    .accesskey = D
+
+carddav-provider-option-other = Darparwr arall…
+
+carddav-url-label =
+    .value = URL CardDAV:
+    .accesskey = V
+
+carddav-username-label =
+    .value = Enw Defnyddiwr:
+    .accesskey = E
+carddav-username-input =
+    .placeholder = you@example.com
+
+carddav-password-label =
+    .value = Cyfrinair:
+    .accesskey = c
+carddav-password-input =
+    .placeholder = Cyfrinair
+
+carddav-remember-password =
+    .label = Cofio'r cyfrinair
+    .accesskey = o
+
+carddav-loading = Chwilio am y ffurfweddiad…
+carddav-connection-error = Methu cysylltu.
+carddav-none-found = Heb ddod o hyd i lyfrau cyfeiriadau i'w hychwanegu ar gyfer y cyfrif penodedig.
+carddav-already-added = Mae'r holl lyfrau cyfeiriadau ar gyfer y cyfrif penodol eisoes wedi'u hychwanegu.
+
+carddav-available-books = Llyfrau cyfeiriadau sydd ar gael:
diff --git a/l10n-cy/mail/messenger/addressbook/abCardDAVProperties.ftl b/l10n-cy/mail/messenger/addressbook/abCardDAVProperties.ftl
new file mode 100644
index 0000000000..998f1ba215
--- /dev/null
+++ b/l10n-cy/mail/messenger/addressbook/abCardDAVProperties.ftl
@@ -0,0 +1,37 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+carddav-url-label =
+    .value = URL CardDAV:
+    .accesskey = V
+carddav-refreshinterval-label =
+    .label = Cydweddu:
+    .accesskey = C
+# Variables:
+#   $minutes (integer) - Number of minutes between address book synchronizations
+carddav-refreshinterval-minutes-value =
+    .label =
+        { $minutes ->
+            [zero] pob munud
+            [one] pob munud
+            [two] pob { $minutes } funud
+            [few] pob { $minutes } munud
+            [many] pob { $minutes } munud
+           *[other] pob { $minutes } munud
+        }
+# Variables:
+#   $hours (integer) - Number of hours between address book synchronizations
+carddav-refreshinterval-hours-value =
+    .label =
+        { $hours ->
+            [zero] pob awr
+            [one] pob awr
+            [two] pob { $hours } awr
+            [few] pob { $hours } awr
+            [many] pob { $hours } awr
+           *[other] pob { $hours } awr
+        }
+carddav-readonly-label =
+    .label = Darllen yn unig
+    .accesskey = D
diff --git a/l10n-cy/mail/messenger/menubar.ftl b/l10n-cy/mail/messenger/menubar.ftl
new file mode 100644
index 0000000000..892a2a7ab9
--- /dev/null
+++ b/l10n-cy/mail/messenger/menubar.ftl
@@ -0,0 +1,25 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## View Menu
+
+menu-view-charset =
+    .label = Amgodiad Testun
+    .accesskey = A
+
+## Mail Toolbar
+
+toolbar-junk-button =
+    .label = Sbwriel
+    .tooltiptext = Marcio'r negeseuon hyn fel sbwriel
+toolbar-not-junk-button =
+    .label = Nid Sbwriel
+    .tooltiptext = Marcio'r negeseuon hyn fel nid sbwriel
+toolbar-delete-button =
+    .label = Dileu
+    .tooltiptext = Dileu'r negeseuon neu ffolderi hyn
+toolbar-undelete-button =
+    .label = Dad-ddileu
+    .tooltiptext = Dad-ddileu'r negeseuon hyn
diff --git a/l10n-cy/mail/messenger/messenger.ftl b/l10n-cy/mail/messenger/messenger.ftl
new file mode 100644
index 0000000000..0765c2591d
--- /dev/null
+++ b/l10n-cy/mail/messenger/messenger.ftl
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-rights-notification-text = Mae { -brand-short-name } yn feddalwedd cod agored am ddim, wedi'i adeiladu gan gymuned o filoedd o bob cwr o'r byd.
+
+## Folder Pane
+
+folder-pane-toolbar =
+    .toolbarname = Bar Offer Paen Ffolder
+    .accesskey = P
+folder-pane-header-label = Ffolderi
+
+## Folder Toolbar Header Popup
+
+folder-toolbar-hide-toolbar-toolbarbutton =
+    .label = Cuddio'r Bar Offer
+    .accesskey = C
+show-all-folders-label =
+    .label = Pob Ffolder
+    .accesskey = P
+show-unread-folders-label =
+    .label = Ffolderi Heb eu Darllen
+    .accesskey = H
+show-favorite-folders-label =
+    .label = Hoff Ffolderi
+    .accesskey = H
+show-smart-folders-label =
+    .label = Ffolderi Cyfun
+    .accesskey = y
+show-recent-folders-label =
+    .label = Ffolderi Diweddar
+    .accesskey = D
+folder-toolbar-toggle-folder-compact-view =
+    .label = Golwg Cryno
+    .accesskey = G
diff --git a/l10n-cy/mail/messenger/messengercompose/messengercompose.ftl b/l10n-cy/mail/messenger/messengercompose/messengercompose.ftl
new file mode 100644
index 0000000000..8f320890aa
--- /dev/null
+++ b/l10n-cy/mail/messenger/messengercompose/messengercompose.ftl
@@ -0,0 +1,82 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# Addressing widget
+
+#   $type (String) - the type of the addressing row
+remove-address-row-type = Tynnwch y maes { $type }
+#   $type (String) - the type of the addressing row
+remove-address-row-type-label =
+    .tooltiptext = Tynnwch y maes { $type }
+#   $type (String) - the type of the addressing row
+#   $count (Number) - the number of address pills currently present in the addressing row
+address-input-type-aria-label =
+    { $count ->
+        [0] { $type }
+        [zero] { $type } gydag un cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arno.
+        [one] { $type } gyda { $count } cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arnyn nhw.
+        [two] { $type } gyda { $count } cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arnyn nhw.
+        [few] { $type } gyda { $count } cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arnyn nhw.
+        [many] { $type } gyda { $count } cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arnyn nhw.
+       *[other] { $type } gyda { $count } cyfeiriad, defnyddiwch fysell y saeth chwith i ganolbwyntio arnyn nhw.
+    }
+#   $email (String) - the email address
+#   $count (Number) - the number of address pills currently present in the addressing row
+pill-aria-label =
+    { $count ->
+        [zero] { $email }, 1 o { $count }: pwyswch Enter i olygu, Delete i ddileu
+        [one] { $email }: pwyswch Enter i olygu, Delete i ddileu
+        [two] { $email }, 1 o { $count }: pwyswch Enter i olygu, Delete i ddileu
+        [few] { $email }, 1 o { $count }: pwyswch Enter i olygu, Delete i ddileu
+        [many] { $email }, 1 o { $count }: pwyswch Enter i olygu, Delete i ddileu
+       *[other] { $email }, 1 o { $count }: pwyswch Enter i olygu, Delete i ddileu
+    }
+#   $email (String) - the email address
+pill-tooltip-invalid-address = Nid yw { $email } yn gyfeiriad e-bost dilys
+#   $email (String) - the email address
+pill-tooltip-not-in-address-book = Nid yw { $email } yn eich llyfr cyfeiriadau
+pill-action-edit =
+    .label = Golygu Cyfeiriad
+    .accesskey = G
+pill-action-move-to =
+    .label = Symud i
+    .accesskey = S
+pill-action-move-cc =
+    .label = Symud i CC
+    .accesskey = C
+pill-action-move-bcc =
+    .label = Symud i Bcc
+    .accesskey = B
+#   $count (Number) - the number of attachments in the attachment bucket
+attachment-bucket-count =
+    .value =
+        { $count ->
+            [1] { $count } Atodiad
+            [zero] { $count } Atodiadau
+            [one] { $count } Atodiad
+            [two] { $count } Atodiad
+            [few] { $count } Atodiad
+            [many] { $count } Atodiad
+           *[other] { $count } Atodiad
+        }
+    .accesskey = A
+#   $count (Number) - the number of attachments in the attachment bucket
+attachments-placeholder-tooltip =
+    .tooltiptext =
+        { $count ->
+            [1] Atodiadau
+            [zero] { $count } Atodiadau
+            [one] { $count } Atodiad
+            [two] { $count } Atodiad
+            [few] { $count } Atodiad
+            [many] { $count } Atodiad
+           *[other] { $count } Atodiad
+        }
+#   { attachment-bucket-count.accesskey } - Do not localize this message.
+key-toggle-attachment-pane =
+    .key = { attachment-bucket-count.accesskey }
+button-return-receipt =
+    .label = Derbynneb
+    .tooltiptext = Gofyn am dderbynneb dychwelyd i'r neges hon
diff --git a/l10n-cy/mail/messenger/newInstall.ftl b/l10n-cy/mail/messenger/newInstall.ftl
new file mode 100644
index 0000000000..6ef3595d21
--- /dev/null
+++ b/l10n-cy/mail/messenger/newInstall.ftl
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+connection-window =
+    .title = Newyddion Pwysig
+continue-button =
+    .label = Parhau
+main-text = Mae gan y gosodiad hwn o { -brand-short-name } broffil newydd. Nid yw'n rhannu data e-bost, cyfrineiriau, dewisiadau defnyddwyr, a llyfrau cyfeiriadau â gosodiadau eraill o { -brand-product-name } (gan gynnwys { -brand-product-name }, { -brand-product-name } Beta, a { -brand-product-name } Daily) ar y cyfrifiadur hwn.
diff --git a/l10n-cy/mail/messenger/newInstallPage.ftl b/l10n-cy/mail/messenger/newInstallPage.ftl
new file mode 100644
index 0000000000..97438d5c73
--- /dev/null
+++ b/l10n-cy/mail/messenger/newInstallPage.ftl
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+title = Newyddion Pwysig
+heading = Newidiadau i'ch proffil { -brand-short-name }
+changed-title = Beth sydd wedi newid?
+changed-desc-profiles = Mae gan y gosodiad hwn o { -brand-short-name } broffil newydd. Proffil yw'r set o ffeiliau lle mae { -brand-product-name } yn cadw gwybodaeth fel data e-bost, cyfrineiriau, dewisiadau defnyddwyr, a llyfrau cyfeiriadau.
+changed-desc-dedicated = Er mwyn ei gwneud hi'n haws ac yn fwy diogel newid rhwng gosodiadau o { -brand-product-name } (gan gynnwys { -brand-product-name }, { -brand-product-name } Beta, a { -brand-product-name } Daily), mae gan y gosodiad hwn broffil penodol bellach. Nid yw'n rhannu'ch gwybodaeth a gadwyd yn awtomatig â gosodiadau { -brand-product-name } eraill.
+lost = <b>Nid ydych wedi colli unrhyw ddata personol neu gyfaddasiadau.</b> Os ydych eisoes wedi cadw gwybodaeth i { -brand-product-name } ar y cyfrifiadur hwn, mae ar gael o hyd mewn gosodiad { -brand-product-name } arall.
+options-title = Beth yw fy newisiadau?
+options-do-nothing = Os na wnewch chi unrhyw beth, bydd eich data proffil yn { -brand-short-name } yn wahanol i ddata proffil mewn gosodiadau eraill o { -brand-product-name }.
+resources = Adnoddau
+about-pofiles-link = Gweld a Rheoli'ch Proffiliau
+support-link = Defnyddio'r Rheolwr Proffil - Erthygl Gymorth
diff --git a/l10n-cy/mail/messenger/openpgp/backupKeyPassword.ftl b/l10n-cy/mail/messenger/openpgp/backupKeyPassword.ftl
new file mode 100644
index 0000000000..7aa1dc17af
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/backupKeyPassword.ftl
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+set-password-window =
+    .title = Dewiswch gyfrinair i wneud copi wrth gefn o'ch Allwedd OpenPGP
+
+set-password-legend = Dewiswch Gyfrinair
+
+set-password-message = Bydd y cyfrinair wrth gefn yma'n amddiffyn yr allwedd gyfrinachol OpenPGP wrth gefn rydych ar fin ei chreu.  Rhaid gosod y cyfrinair i barhau gyda'r ffeil wrth gefn.
+
+set-password-backup-pw =
+    .value = Cyfrinair wrth gefn Allwedd Cyfrinachol:
+
+set-password-repeat-backup-pw =
+    .value = Cyfrinair wrth gefn Allwedd Cyfrinachol (eto):
+
+set-password-reminder = <b>Pwysig!</b> Os byddwch yn anghofio eich cyfrinair diogelwch wrth gefn, ni fydd modd i chi adfer y ffeil wrth gefn yma eto.  Cofnodwch hwn mewn man diogel.
+
+password-quality-meter = Mesurydd ansawdd cyfrinair
diff --git a/l10n-cy/mail/messenger/openpgp/changeExpiryDlg.ftl b/l10n-cy/mail/messenger/openpgp/changeExpiryDlg.ftl
new file mode 100644
index 0000000000..e2b941038a
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/changeExpiryDlg.ftl
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+openpgp-change-key-expiry-title =
+    .title = Newid Dod i Ben yr Allwedd
+
+info-will-expire = Mae'r allwedd hon wedi'i ffurfweddu i ddod i ben ar { $date }
+info-already-expired = Mae'r allwedd hon eisoes wedi dod i ben.
+info-does-not-expire = Mae'r allwedd hon wedi'i ffurfweddu i beidio byth â dod i ben.
+
+info-explanation-1 = <b>Ar ôl i allwedd ddod i ben</b>, nid yw bellach yn bosibl ei defnyddio ar gyfer amgryptio neu arwyddo digidol.
+
+info-explanation-2 = I ddefnyddio'r allwedd hon am gyfnod hirach, newidiwch ei dyddiad dod i ben, ac yna rhannwch yr allwedd gyhoeddus gyda'ch partneriaid sgwrsio eto.
+
+expire-dont-change =
+    .label = Peidiwch â newid y dyddiad dod i ben
+expire-never-label =
+    .label = Ni fydd yr allwedd byth yn dod i ben
+expire-in-label =
+    .label = Bydd yr allwedd yn dod i ben ar:
+expire-in-months = Mis
diff --git a/l10n-cy/mail/messenger/openpgp/composeKeyStatus.ftl b/l10n-cy/mail/messenger/openpgp/composeKeyStatus.ftl
new file mode 100644
index 0000000000..48a13891bc
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/composeKeyStatus.ftl
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+openpgp-compose-key-status-intro-need-keys = I anfon neges wedi'i hamgryptio o ben-i-ben, rhaid i chi gael a derbyn allwedd gyhoeddus ar gyfer pob derbynnydd.
+openpgp-compose-key-status-keys-heading = Argaeledd allweddi OpenPGP:
+openpgp-compose-key-status-title =
+    .title = Diogelwch Negeseuon OpenPGP
+openpgp-compose-key-status-recipient =
+    .label = Derbynnydd
+openpgp-compose-key-status-status =
+    .label = Statws
+openpgp-compose-key-status-open-details = Rheoli allweddi ar gyfer derbynnydd dewisol...
+openpgp-recip-good = Iawn
+openpgp-recip-missing = dim allwedd ar gael
+openpgp-recip-none-accepted = dim allwedd wedi'i derbyn
diff --git a/l10n-cy/mail/messenger/openpgp/keyWizard.ftl b/l10n-cy/mail/messenger/openpgp/keyWizard.ftl
new file mode 100644
index 0000000000..104a3b0844
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/keyWizard.ftl
@@ -0,0 +1,192 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#   $identity (String) - the email address of the currently selected identity
+key-wizard-dialog-window =
+    .title = Ychwanegu Allwedd OpenPGP Personol ar gyfer { $identity }
+
+key-wizard-button =
+    .buttonlabelaccept = Parhau
+    .buttonlabelhelp = Nôl
+
+key-wizard-warning = <b>Os oes gennych allwedd bersonol bresennol</b> ar gyfer y cyfeiriad e-bost hwn, dylech ei fewnforio. Fel arall ni fydd gennych fynediad i'ch archifau o e-byst wedi'u hamgryptio, nac yn gallu darllen e-byst wedi'u hamgryptio rydych yn eu derbyn gan bobl sy'n dal i ddefnyddio'ch allwedd bresennol.
+
+key-wizard-learn-more = Dysgu rhagor
+
+radio-create-key =
+    .label = Creu Allwedd OpenPGP newydd
+    .accesskey = C
+
+radio-import-key =
+    .label = Mewnforio Allwedd OpenPGP cyfredol
+    .accesskey = M
+
+radio-gnupg-key =
+    .label = Defnyddio'ch allwedd allanol trwy GnuPG (e.e. o gerdyn clyfar)
+    .accesskey = D
+
+## Generate key section
+
+openpgp-generate-key-title = Cynhyrchu Allwedd OpenPGP
+
+openpgp-generate-key-info = <b>Gall cynhyrchu allweddol gymryd rhai munudau i'w gwblhau.</b> Peidiwch â gadael y rhaglen tra bo'r allwedd yn cael ei gynhyrchu. Bydd pori neu berfformio gweithrediadau disg-ddwys yn ystod cynhyrchu'r allwedd yn ailgyflenwi'r 'gronfa ar hap' ac yn cyflymu'r broses. Cewch eich rhybuddio pan fydd cynhyrchu'r allweddol wedi'i gwblhau.
+
+openpgp-keygen-expiry-title = Allwedd yn dod i ben
+
+openpgp-keygen-expiry-description = Diffiniwch amser dod i ben eich allwedd sydd newydd ei chynhyrchu. Yn ddiweddarach, gallwch reoli'r dyddiad i'w ymestyn os oes angen.
+
+radio-keygen-expiry =
+    .label = Allwedd yn dod i ben ar
+    .accesskey = l
+
+radio-keygen-no-expiry =
+    .label = Nid yw'r allwedd yn dod i ben
+    .accesskey = N
+
+openpgp-keygen-days-label =
+    .label = diwrnod
+openpgp-keygen-months-label =
+    .label = mis
+openpgp-keygen-years-label =
+    .label = blwyddyn
+
+openpgp-keygen-advanced-title = Gosodiadau uwch
+
+openpgp-keygen-advanced-description = Rheoli gosodiadau uwch eich Allwedd OpenPGP.
+
+openpgp-keygen-keytype =
+    .value = Math o allwedd:
+    .accesskey = M
+
+openpgp-keygen-keysize =
+    .value = Maint yr allwedd:
+    .accesskey = a
+
+openpgp-keygen-type-rsa =
+    .label = RSA
+
+openpgp-keygen-type-ecc =
+    .label = ECC (Cromlin Elliptig)
+
+openpgp-keygen-button = Cynhyrchu allwedd
+
+openpgp-keygen-progress-title = Cynhyrchu eich Allwedd OpenPGP newydd ...
+
+openpgp-keygen-import-progress-title = Mewnforio eich Allweddi OpenPGP...
+
+openpgp-import-success = Allweddi OpenPGP wedi'u mewnforio'n llwyddiannus!
+
+openpgp-import-success-title = Cwblhewch y broses fewnforio
+
+openpgp-import-success-description = I ddechrau defnyddio'ch allwedd OpenPGP wedi'i fewnforio ar gyfer amgryptio e-bost, caewch y dialog hwn ac ewch i'ch Gosodiadau Cyfrif i'w ddewis.
+
+openpgp-keygen-confirm =
+    .label = Cadarnhau
+
+openpgp-keygen-dismiss =
+    .label = Diddymu
+
+openpgp-keygen-cancel =
+    .label = Diddymu'r broses ...
+
+openpgp-keygen-import-complete =
+    .label = Cau
+    .accesskey = C
+
+openpgp-keygen-missing-username = Nid oes enw wedi'i nodi ar gyfer y cyfrif cyfredol. Rhowch werth yn y maes "Eich enw" yng ngosodiadau'r cyfrif.
+openpgp-keygen-long-expiry = Nid oes modd i chi greu allwedd sy'n dod i ben mewn mwy na 100 mlynedd.
+openpgp-keygen-short-expiry = Rhaid i'ch allwedd fod yn ddilys am o leiaf un diwrnod.
+
+openpgp-keygen-ongoing = Eisoes wrthi'n cynhyrchu allwedd!
+
+openpgp-keygen-error-core = Methu cychwyn Gwasanaeth Craidd OpenPGP
+
+openpgp-keygen-error-failed = Yn annisgwyl, methwyd cynhyrchu allwedd OpenPGP
+
+#   $identity (String) - the newly generate OpenPGP Key
+openpgp-keygen-error-revocation = Crëwyd Allwedd OpenPGP yn llwyddiannus, ond methodd â chael dirymiad ar gyfer allwedd { $key }
+
+openpgp-keygen-abort-title = Atal cynhyrchu allwedd?
+openpgp-keygen-abort = Mae cynhyrchu allwedd OpenPGP ar y gweill ar hyn o bryd, a ydych chi'n siŵr eich bod am ei ddiddymu?
+
+#   $identity (String) - the name and email address of the currently selected identity
+openpgp-key-confirm = Cynhyrchu allwedd gyhoeddus a chyfrinachol ar gyfer { $identity }?
+
+## Import Key section
+
+openpgp-import-key-title = Mewnforio Allwedd OpenPGP personol sy'n bodoli eisoes
+
+openpgp-import-key-legend = Dewis ffeil a gadwyd wrth gefn.
+
+openpgp-import-key-description = Gallwch fewnforio allweddi personol a gafodd eu creu gyda meddalwedd OpenPGP arall.
+
+openpgp-import-key-info = Gall meddalwedd arall ddisgrifio allwedd bersonol gan ddefnyddio termau amgen fel eich allwedd eich hun, allwedd gyfrinachol, allwedd breifat neu bar o allweddi.
+
+#   $count (Number) - the number of keys found in the selected files
+openpgp-import-key-list-amount =
+    { $count ->
+        [zero] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+        [one] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+        [two] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+        [few] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+        [many] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+       *[other] Daeth Thunderbird o hyd i allweddi { $count } y mae modd eu mewnforio.
+    }
+
+openpgp-import-key-list-description = Cadarnhewch pa allweddi y mae modd eu trin fel eich allweddi personol. Dim ond allweddi y gwnaethoch chi eu creu eich hun ac sy'n dangos eich hunaniaeth eich hun y dylid eu defnyddio fel allweddi personol. Gallwch newid yr dewis hwn yn nes ymlaen yn y dialog Priodweddau Allweddi.
+
+openpgp-import-key-list-caption = Bydd allweddi sydd wedi'u marcio i'w trin fel Allweddi Personol yn cael eu rhestru yn yr adran Amgryptio Ben-i-Ben. Bydd y lleill ar gael y tu mewn i'r Rheolwr Allweddi.
+
+openpgp-passphrase-prompt-title = Mae angen cyfrinymadrodd
+
+#   $identity (String) - the id of the key being imported
+openpgp-passphrase-prompt = Rhowch y cyfrinymadrodd i ddatgloi'r allwedd ganlynol: { $key }
+
+openpgp-import-key-button =
+    .label = Dewis Ffeil i'w Mewnforio ...
+    .accesskey = D
+
+import-key-file = Mewnforio Ffeil Allwedd OpenPGP
+
+import-key-personal-checkbox =
+    .label = Trin yr allwedd hon fel Allwedd Bersonol
+
+gnupg-file = Ffeiliau GnuPG
+
+import-error-file-size = <b>Gwall!</b> Nid yw ffeiliau mwy na 5MB yn cael eu cefnogi.
+
+#   $error (String) - the reported error from the failed key import method
+import-error-failed = <b>Gwall!</b> Wedi methu mewnforio ffeil. { $error }
+
+#   $error (String) - the reported error from the failed key import method
+openpgp-import-keys-failed = <b>Gwall!</b> Wedi methu mewnforio allweddi. { $error }
+
+openpgp-import-identity-label = Hunaniaeth
+
+openpgp-import-fingerprint-label = Bysbrint
+
+openpgp-import-created-label = Crëwyd
+
+openpgp-import-bits-label = Didau
+
+openpgp-import-key-props =
+    .label = Priodweddau'r Allwedd
+    .accesskey = P
+
+## External Key section
+
+openpgp-external-key-title = Allwedd GnuPG Allanol
+
+openpgp-external-key-description = Ffurfweddu allwedd GnuPG allanol trwy nodi ID yr Allwedd
+
+openpgp-external-key-info = Yn ogystal, rhaid i chi ddefnyddio'r Rheolwr Allweddi i fewnforio a derbyn yr Allwedd Gyhoeddus gyfatebol.
+
+openpgp-external-key-warning = <b>Dim ond un Allwedd GnuPG allanol y gallwch chi ei ffurfweddu.</b> Bydd eich cofnod blaenorol yn cael ei ddisodli.
+
+openpgp-save-external-button = Cadw ID yr allwedd
+
+openpgp-external-key-label = ID Allwedd Gyfrinachol:
+
+openpgp-external-key-input =
+    .placeholder = 123456789341298340
diff --git a/l10n-cy/mail/messenger/openpgp/msgReadStatus.ftl b/l10n-cy/mail/messenger/openpgp/msgReadStatus.ftl
new file mode 100644
index 0000000000..f90238b3d1
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/msgReadStatus.ftl
@@ -0,0 +1,39 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Message Header Encryption Button
+
+message-header-show-security-info-key = D
+#   $type (String) - the shortcut key defined in the message-header-show-security-info-key
+message-security-button =
+    .title =
+        { PLATFORM() ->
+            [macos] Dangos Diogelwch Negeseuon (⌘ ⌥ { message-header-show-security-info-key })
+           *[other] Dangos Diogelwch Negeseuon (Ctrl+Alt+{ message-header-show-security-info-key }
+        }
+openpgp-view-signer-key =
+    .label = Gweld allwedd llofnodwr
+openpgp-view-your-encryption-key =
+    .label = Gweld eich allwedd dadgryptio
+openpgp-openpgp = OpenPGP
+openpgp-no-sig = Dim Llofnod Digidol
+openpgp-uncertain-sig = Llofnod Digidol Ansicr
+openpgp-invalid-sig = Llofnod Digidol Annilys
+openpgp-good-sig = Llofnod Digidol Da
+openpgp-sig-uncertain-no-key = Mae'r neges hon yn cynnwys llofnod digidol, ond mae'n ansicr a yw'n gywir. I wirio'r llofnod, mae angen i chi gael copi o allwedd gyhoeddus yr anfonwr.
+openpgp-sig-uncertain-uid-mismatch = Mae'r neges hon yn cynnwys llofnod digidol, ond canfuwyd diffyg cyfatebiaeth. Anfonwyd y neges o gyfeiriad e-bost nad yw'n cyd-fynd ag allwedd gyhoeddus y llofnodwr.
+openpgp-sig-uncertain-not-accepted = Mae'r neges hon yn cynnwys llofnod digidol, ond nid ydych wedi penderfynu eto a yw allwedd y llofnodwr yn dderbyniol i chi.
+openpgp-sig-invalid-rejected = Mae'r neges hon yn cynnwys llofnod digidol, ond rydych chi wedi penderfynu gwrthod allwedd y llofnodwr yn flaenorol.
+openpgp-sig-invalid-technical-problem = Mae'r neges hon yn cynnwys llofnod digidol, ond canfuwyd gwall technegol. Naill ai mae'r neges wedi'i llygru, neu mae'r neges wedi'i haddasu gan rywun arall.
+openpgp-sig-valid-unverified = Mae'r neges hon yn cynnwys llofnod digidol dilys o allwedd rydych chi eisoes wedi'i derbyn. Fodd bynnag, nid ydych wedi gwirio eto bod yr allwedd yn eiddo i'r anfonwr mewn gwirionedd.
+openpgp-sig-valid-verified = Mae'r neges hon yn cynnwys llofnod digidol dilys o allwedd wedi'i gwirio.
+openpgp-sig-valid-own-key = Mae'r neges hon yn cynnwys llofnod digidol dilys o'ch allwedd bersonol.
+openpgp-sig-key-id = ID allwedd llofnodwr: { $key }
+openpgp-sig-key-id-with-subkey-id = ID allwedd llofnodwr: { $key } (ID Is-allwedd: { $subkey })
+openpgp-enc-key-id = ID eich allwedd dadgryptio: { $key }
+openpgp-enc-key-with-subkey-id = ID eich allwedd dadgryptio: { $key } (ID Is-allwedd: { $subkey })
+openpgp-unknown-key-id = Allwedd anhysbys
+openpgp-other-enc-additional-key-ids = Yn ogystal, amgryptiwyd y neges i berchnogion yr allweddi canlynol:
+openpgp-other-enc-all-key-ids = Amgryptiwyd y neges i berchnogion yr allweddi canlynol:
diff --git a/l10n-cy/mail/messenger/openpgp/oneRecipientStatus.ftl b/l10n-cy/mail/messenger/openpgp/oneRecipientStatus.ftl
new file mode 100644
index 0000000000..504aa7996b
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/oneRecipientStatus.ftl
@@ -0,0 +1,30 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+openpgp-one-recipient-status-title =
+    .title = Diogelwch Negeseuon OpenPGP
+openpgp-one-recipient-status-status =
+    .label = Statws
+openpgp-one-recipient-status-key-id =
+    .label = ID Allwedd
+openpgp-one-recipient-status-created-date =
+    .label = Crëwyd
+openpgp-one-recipient-status-expires-date =
+    .label = Daw i ben
+openpgp-one-recipient-status-open-details =
+    .label = Agor manylion a golygu derbyniad...
+openpgp-one-recipient-status-discover =
+    .label = Darganfod allwedd newydd neu wedi'i diweddaru
+
+openpgp-one-recipient-status-instruction1 = I anfon neges wedi'i hamgryptio o ben-i-ben at dderbynnydd, mae angen i chi gael gafael ar ei allwedd gyhoeddus OpenPGP a'i nodi fel y'i derbyniwyd.
+openpgp-one-recipient-status-instruction2 = I gael eu allwedd gyhoeddus, eu mewnforio o e-bost y maent wedi'i anfon atoch ac sy'n ei gynnwys. Fel arall, gallwch geisio darganfod eu allwedd gyhoeddus ar gyfeiriadur.
+
+openpgp-key-own = Derbyniwyd (allwedd bersonol)
+openpgp-key-secret-not-personal = Ddim yn ddefnyddiadwy
+openpgp-key-verified = Derbyniwyd (dilyswyd)
+openpgp-key-unverified = Derbyniwyd (heb ei wirio)
+openpgp-key-undecided = Heb ei dderbyn (heb benderfynu)
+openpgp-key-rejected = Heb ei dderbyn (gwrthodwyd)
+
+openpgp-intro = Allweddi cyhoeddus sydd ar gael ar gyfer { $key }
diff --git a/l10n-cy/mail/messenger/openpgp/openpgp-frontend.ftl b/l10n-cy/mail/messenger/openpgp/openpgp-frontend.ftl
new file mode 100644
index 0000000000..160d225beb
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/openpgp-frontend.ftl
@@ -0,0 +1,49 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+openpgp-manage-keys-openpgp-cmd =
+    .label = Rheolwr Allweddi OpenPGP
+    .accesskey = R
+openpgp-ctx-decrypt-open =
+    .label = Dadgryptio ac Agor
+    .accesskey = D
+openpgp-ctx-decrypt-save =
+    .label = Dadgryptio a Chadw Fel…
+    .accesskey = C
+openpgp-ctx-import-key =
+    .label = Mewnforio Allwedd OpenPGP
+    .accesskey = M
+openpgp-ctx-verify-att =
+    .label = Gwirio Llofnod
+    .accesskey = G
+openpgp-has-sender-key = Mae'r neges hon yn honni ei bod yn cynnwys allwedd gyhoeddus OpenPGP yr anfonwr.
+openpgp-be-careful-new-key = Rhybudd: Mae'r allwedd gyhoeddus OpenPGP newydd yn y neges hon yn wahanol i'r allweddi cyhoeddus y gwnaethoch eu derbyn o'r blaen gan { $email }
+openpgp-import-sender-key =
+    .label = Mewnforio…
+openpgp-search-keys-openpgp =
+    .label = Darganfod Allweddi OpenPGP
+openpgp-missing-signature-key = Llofnodwyd y neges hon ag allwedd nad yw gennych chi eto.
+openpgp-search-signature-key =
+    .label = Darganfod…
+# Don't translate the terms "OpenPGP" and "MS-Exchange"
+openpgp-broken-exchange-opened = Mae hon yn neges OpenPGP gafodd ei llygru yn ôl pob golwg gan MS-Exchange ac nid oes modd ei hatgyweirio oherwydd iddi gael ei hagor o ffeil leol. Copïwch y neges i mewn i ffolder e-bost i roi cynnig ar ei hatgyweirio'n awtomatig.
+openpgp-broken-exchange-info = Neges OpenPGP yw hon a gafodd ei llygru yn ôl pob golwg gan MS-Exchange. Os na yw cynnwys y neges yn cael ei ddangos yn ôl y disgwyl, gallwch roi cynnig ar atgyweiriad awtomatig.
+openpgp-broken-exchange-repair =
+    .label = Atgyweirio neges
+openpgp-broken-exchange-wait = Arhoswch…
+openpgp-cannot-decrypt-because-mdc =
+    Neges wedi'i hamgryptio yw hon sy'n defnyddio hen fecanwaith bregus.
+    Gall fod wedi cael ei addasu wrth gael ei gludo, gyda'r bwriad o ddwyn ei gynnwys.
+    Er mwyn atal y risg hon, nid yw'r cynnwys yn cael ei ddangos.
+openpgp-cannot-decrypt-because-missing-key = Nid yw'r allwedd gyfrinachol sy'n ofynnol i ddadgryptio'r neges hon ar gael.
+openpgp-partially-signed =
+    Dim ond is-set o'r neges hon a lofnodwyd yn ddigidol gan ddefnyddio OpenPGP.
+    Os cliciwch y botwm gwirio, bydd y rhannau heb ddiogelwch yn cael eu cuddio, a bydd statws y llofnod digidol yn cael ei ddangos.
+openpgp-partially-encrypted =
+    Dim ond is-set o'r neges hon a amgryptiwyd gan ddefnyddio OpenPGP.
+    Nid yw rhannau darllenadwy o'r neges sy'n cael eu dangos eisoes wedi eu hamgryptio.
+    Os cliciwch y botwm dadgryptio, bydd cynnwys y rhannau wedi'u hamgryptio yn cael eu dangos.
+openpgp-reminder-partial-display = Nodyn i'ch atgoffa: Dim ond is-set o'r neges wreiddiol yw'r neges sy'n cael ei ddangos isod.
+openpgp-partial-verify-button = Gwirio
+openpgp-partial-decrypt-button = Dadgryptio
diff --git a/l10n-cy/mail/messenger/openpgp/openpgp.ftl b/l10n-cy/mail/messenger/openpgp/openpgp.ftl
new file mode 100644
index 0000000000..72395d5aed
--- /dev/null
+++ b/l10n-cy/mail/messenger/openpgp/openpgp.ftl
@@ -0,0 +1,670 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+e2e-intro-description = I anfon negeseuon wedi'u hamgryptio neu wedi'u llofnodi'n ddigidol, mae angen i chi ffurfweddu technoleg amgryptio, naill ai OpenPGP neu S / MIME.
+e2e-intro-description-more = Dewiswch eich allwedd bersonol i alluogi defnyddio OpenPGP, neu'ch tystysgrif bersonol i alluogi defnyddio S/MIME. Ar gyfer allwedd neu dystysgrif bersonol chi sy'n berchen ar yr allwedd gyfrinachol gyfatebol.
+openpgp-key-user-id-label = Cyfrif / ID Defnyddiwr
+openpgp-keygen-title-label =
+    .title = Cynhyrchu Allwedd OpenPGP
+openpgp-cancel-key =
+    .label = Diddymu
+    .tooltiptext = Diddymu Cynhyrchu Allwedd
+openpgp-key-gen-expiry-title =
+    .label = Allwedd yn dod i ben
+openpgp-key-gen-expire-label = Allwedd yn dod i ben ymhen
+openpgp-key-gen-days-label =
+    .label = diwrnod
+openpgp-key-gen-months-label =
+    .label = mis
+openpgp-key-gen-years-label =
+    .label = b/mlynedd
+openpgp-key-gen-no-expiry-label =
+    .label = Nid yw'r allwedd yn dod i ben
+openpgp-key-gen-key-size-label = Maint yr allwedd
+openpgp-key-gen-console-label = Cynhyrchu Allwedd
+openpgp-key-gen-key-type-label = Math o allwedd
+openpgp-key-gen-key-type-rsa =
+    .label = RSA
+openpgp-key-gen-key-type-ecc =
+    .label = ECC (Cromlin Eliptig)
+openpgp-generate-key =
+    .label = Cynhyrchu allwedd
+    .tooltiptext = Yn cynhyrchu allwedd OpenPGP cydymffurfiol ar gyfer amgryptiad a/neu lofnodi
+openpgp-advanced-prefs-button-label =
+    .label = Uwch…
+openpgp-keygen-desc = <a data-l10n-name="openpgp-keygen-desc-link">SYLWCH: Gall cynhyrchu allweddol gymryd rhai munudau i'w gwblhau.</a> Peidiwch â gadael y rhaglen tra bo'r allwedd yn cael ei gynhyrchu. Bydd pori neu berfformio gweithrediadau disg-ddwys yn ystod cynhyrchu'r allwedd yn ailgyflenwi'r 'gronfa ar hap' ac yn cyflymu'r broses. Cewch eich rhybuddio pan fydd cynhyrchu'r allweddol wedi'i gwblhau.
+openpgp-key-expiry-label =
+    .label = Dod i ben
+openpgp-key-id-label =
+    .label = ID Allwedd
+openpgp-cannot-change-expiry = Mae hwn yn allwedd gyda strwythur cymhleth, nid yw newid ei ddyddiad dod i ben yn cael ei gefnogi.
+openpgp-key-man-title =
+    .title = Rheolwr Allweddi OpenPGP
+openpgp-key-man-generate =
+    .label = Pâr Allweddi Newydd
+    .accesskey = P
+openpgp-key-man-gen-revoke =
+    .label = Tystysgrif Dirymu
+    .accesskey = D
+openpgp-key-man-ctx-gen-revoke-label =
+    .label = Cynhyrchu a Chadw Tystysgrif Dirymu
+openpgp-key-man-file-menu =
+    .label = Ffeil
+    .accesskey = F
+openpgp-key-man-edit-menu =
+    .label = Golygu
+    .accesskey = G
+openpgp-key-man-view-menu =
+    .label = Gweld
+    .accesskey = G
+openpgp-key-man-generate-menu =
+    .label = Cynhyrchu
+    .accesskey = C
+openpgp-key-man-keyserver-menu =
+    .label = Gweinydd Allweddi
+    .accesskey = G
+openpgp-key-man-import-public-from-file =
+    .label = Mewnforio Allwedd(i) Cyhoeddus o'r Ffeil
+    .accesskey = M
+openpgp-key-man-import-secret-from-file =
+    .label = Mewnforio Allwedd(i) Cyfrinachol o'r Ffeil
+openpgp-key-man-import-sig-from-file =
+    .label = Mewnforio Dirymiad(au) o'r Ffeil
+openpgp-key-man-import-from-clipbrd =
+    .label = Mewnforio Allwedd(i) o'r Clipfwrdd
+    .accesskey = C
+openpgp-key-man-import-from-url =
+    .label = Mewnforio Allwedd(i) o URL
+    .accesskey = U
+openpgp-key-man-export-to-file =
+    .label = Allforio Allwedd(i) Cyhoeddus i Ffeil
+    .accesskey = F
+openpgp-key-man-send-keys =
+    .label = Anfon Allwedd(i) Cyhoeddus Trwy E-bost
+    .accesskey = E
+openpgp-key-man-backup-secret-keys =
+    .label = Allwedd(i) Cyfrinachol Wrth Gefn I'w Ffeilio
+    .accesskey = G
+openpgp-key-man-discover-cmd =
+    .label = Darganfod Allweddi Ar-lein
+    .accesskey = D
+openpgp-key-man-discover-prompt = I ddarganfod allweddi OpenPGP ar-lein, ar weinydd allweddi neu ddefnyddio protocol WKD, rhowch naill ai gyfeiriad e-bost neu ID allwedd.
+openpgp-key-man-discover-progress = Chwilio…
+openpgp-key-copy-key =
+    .label = Copïo Allwedd Gyhoeddus
+    .accesskey = G
+openpgp-key-export-key =
+    .label = Allforio Allwedd Gyhoeddus I'r Ffeil
+    .accesskey = A
+openpgp-key-backup-key =
+    .label = Gwneud Copi wrth Gefn o Allwedd Gyfrinachol i Ffeil
+    .accesskey = G
+openpgp-key-send-key =
+    .label = Anfon Allwedd Gyhoeddus Trwy E-bost
+    .accesskey = A
+openpgp-key-man-copy-to-clipbrd =
+    .label = Copïo Allwedd(i) Cyhoeddus I'r Clipfwrdd
+    .accesskey = C
+openpgp-key-man-copy-key-ids =
+    .label =
+        { $count ->
+            [zero] Copïo IDau Allwedd i'r Clipfwrdd
+            [one] Copïo ID Allwedd i'r Clipfwrdd
+            [two] Copïo ID Allwedd i'r Clipfwrdd
+            [few] Copïo ID Allwedd i'r Clipfwrdd
+            [many] Copïo ID Allwedd i'r Clipfwrdd
+           *[other] Copïo ID Allwedd i'r Clipfwrdd
+        }
+    .accesskey = I
+openpgp-key-man-copy-fprs =
+    .label =
+        { $count ->
+            [zero] Copïo Bysbrintiau i'r Clipfwrdd
+            [one] Copïo Bysbrint i'r Clipfwrdd
+            [two] Copïo Bysbrint i'r Clipfwrdd
+            [few] Copïo Bysbrint i'r Clipfwrdd
+            [many] Copïo Bysbrint i'r Clipfwrdd
+           *[other] Copïo Bysbrint i'r Clipfwrdd
+        }
+    .accesskey = B
+openpgp-key-man-copy-to-clipboard =
+    .label =
+        { $count ->
+            [zero] Copïo Allweddi Cyhoeddus I'r Clipfwrdd
+            [one] Copïo Allwedd Gyhoeddus I'r Clipfwrdd
+            [two] Copïo Allwedd Gyhoeddus I'r Clipfwrdd
+            [few] Copïo Allwedd Gyhoeddus I'r Clipfwrdd
+            [many] Copïo Allwedd Gyhoeddus I'r Clipfwrdd
+           *[other] Copïo Allwedd Gyhoeddus I'r Clipfwrdd
+        }
+    .accesskey = A
+openpgp-key-man-ctx-expor-to-file-label =
+    .label = Allforio Allweddi i Ffeil
+openpgp-key-man-ctx-copy-to-clipbrd-label =
+    .label = Copïo Allwedd(i) Cyhoeddus I'r Clipfwrdd
+openpgp-key-man-ctx-copy =
+    .label = Copïo
+    .accesskey = C
+openpgp-key-man-ctx-copy-fprs =
+    .label =
+        { $count ->
+            [zero] Bysbrintiau
+            [one] Bysbrint
+            [two] Bysbrint
+            [few] Bysbrint
+            [many] Bysbrint
+           *[other] Bysbrint
+        }
+    .accesskey = B
+openpgp-key-man-ctx-copy-key-ids =
+    .label =
+        { $count ->
+            [zero] ID Allwedd
+            [one] ID Allwedd
+            [two] ID Allwedd
+            [few] ID Allwedd
+            [many] ID Allwedd
+           *[other] ID Allwedd
+        }
+    .accesskey = D
+openpgp-key-man-ctx-copy-public-keys =
+    .label =
+        { $count ->
+            [zero] Allweddi Cyhoeddus
+            [one] Allwedd Gyhoeddus
+            [two] Allwedd Gyhoeddus
+            [few] Allwedd Gyhoeddus
+            [many] Allwedd Gyhoeddus
+           *[other] Allwedd Gyhoeddus
+        }
+    .accesskey = y
+openpgp-key-man-close =
+    .label = Cau
+openpgp-key-man-reload =
+    .label = Ail-lwytho Storfa Allweddi
+    .accesskey = S
+openpgp-key-man-change-expiry =
+    .label = Newid Dyddiad Dod i Ben
+    .accesskey = N
+openpgp-key-man-del-key =
+    .label = Dileu Allwedd(i)
+    .accesskey = D
+openpgp-delete-key =
+    .label = Dileu Allwedd
+    .accesskey = A
+openpgp-key-man-revoke-key =
+    .label = Dirymu Allwedd
+    .accesskey = i
+openpgp-key-man-key-props =
+    .label = Priodweddau Allweddi
+    .accesskey = P
+openpgp-key-man-key-more =
+    .label = Rhagor
+    .accesskey = R
+openpgp-key-man-view-photo =
+    .label = ID Llun
+    .accesskey = L
+openpgp-key-man-ctx-view-photo-label =
+    .label = Gweld ID Llun
+openpgp-key-man-show-invalid-keys =
+    .label = Dangos allweddi annilys
+    .accesskey = D
+openpgp-key-man-show-others-keys =
+    .label = Dangos Allweddi Gan Bobl Eraill
+    .accesskey = B
+openpgp-key-man-user-id-label =
+    .label = Enw
+openpgp-key-man-fingerprint-label =
+    .label = Bysbrint
+openpgp-key-man-select-all =
+    .label = Dewis Pob Allwedd
+    .accesskey = P
+openpgp-key-man-empty-tree-tooltip =
+    .label = Rhowch dermau chwilio yn y blwch uchod
+openpgp-key-man-nothing-found-tooltip =
+    .label = Nid oes unrhyw allweddi yn cyd-fynd â'ch chwilio
+openpgp-key-man-please-wait-tooltip =
+    .label = Arhoswch tra bod allweddi yn cael eu llwytho...
+openpgp-key-man-filter-label =
+    .placeholder = Chwilio am allweddi
+openpgp-key-man-select-all-key =
+    .key = P
+openpgp-key-man-key-details-key =
+    .key = I
+openpgp-key-details-title =
+    .title = Priodweddau'r Allwedd
+openpgp-key-details-signatures-tab =
+    .label = Ardystiadau
+openpgp-key-details-structure-tab =
+    .label = Strwythur
+openpgp-key-details-uid-certified-col =
+    .label = ID Defnyddiwr / Ardystiedig gan
+openpgp-key-details-user-id2-label = Perchennog Honedig Allwedd
+openpgp-key-details-id-label =
+    .label = ID
+openpgp-key-details-key-type-label = Math
+openpgp-key-details-key-part-label =
+    .label = Rhan Allwedd
+openpgp-key-details-algorithm-label =
+    .label = Algorithm
+openpgp-key-details-size-label =
+    .label = Maint
+openpgp-key-details-created-label =
+    .label = Crëwyd
+openpgp-key-details-created-header = Crëwyd
+openpgp-key-details-expiry-label =
+    .label = Dod i ben
+openpgp-key-details-expiry-header = Dod i ben
+openpgp-key-details-usage-label =
+    .label = Defnydd
+openpgp-key-details-fingerprint-label = Bysbrint
+openpgp-key-details-sel-action =
+    .label = Dewis gweithred...
+    .accesskey = g
+openpgp-key-details-also-known-label = Hunaniaethau Honedig Eraill Perchennog yr Allwedd:
+openpgp-card-details-close-window-label =
+    .buttonlabelaccept = Cau
+openpgp-acceptance-label =
+    .label = Eich Derbyn
+openpgp-acceptance-rejected-label =
+    .label = Na, gwrthodwch yr allwedd hon.
+openpgp-acceptance-undecided-label =
+    .label = Ddim eto, efallai yn hwyrach.
+openpgp-acceptance-unverified-label =
+    .label = Iawn, ond nid wyf wedi gwirio mai hwn yw'r allwedd gywir.
+openpgp-acceptance-verified-label =
+    .label = Ydw, rydw i wedi gwirio yn bersonol bod gan yr allwedd hon yr bysbrint cywir.
+key-accept-personal =
+    Yn yr allwedd hon, mae gennych rhan gyhoeddus a rhan gyfrinachol. Gallwch ei defnyddio fel allwedd bersonol.
+    Os rhoddwyd yr allwedd hon i chi gan rywun arall, yna peidiwch â'i defnyddio fel allwedd bersonol.
+key-personal-warning = A wnaethoch chi greu'r allwedd hon eich hun, ac mae perchnogaeth yr allwedd sy'n cael ei ddangos yn cyfeirio atoch chi'ch hun?
+openpgp-personal-no-label =
+    .label = Na, peidio'i defnyddio fel fy allwedd bersonol.
+openpgp-personal-yes-label =
+    .label = Iawn, trin yr allwedd hon fel allwedd bersonol.
+openpgp-copy-cmd-label =
+    .label = Copïo
+
+## e2e encryption settings
+
+#   $count (Number) - the number of configured keys associated with the current identity
+#   $identity (String) - the email address of the currently selected identity
+openpgp-description =
+    { $count ->
+        [0] Nid oes gan Thunderbird allwedd OpenPGP personol ar gyfer <b>{ $identity }</b>
+        [zero] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+        [one] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+        [two] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+        [few] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+        [many] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+       *[other] Mae Thunderbird wedi canfod { $count } allwedd OpenPGP personol sy'n gysylltiedig â <b>{ $identity }</b>
+    }
+#   $count (Number) - the number of configured keys associated with the current identity
+#   $key (String) - the currently selected OpenPGP key
+openpgp-selection-status =
+    { $count ->
+        [0] Dewis allwedd ddilys i alluogi protocol OpenPGP.
+        [zero] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+        [one] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+        [two] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+        [few] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+        [many] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+       *[other] Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>
+    }
+#   $key (String) - the currently selected OpenPGP key
+openpgp-selection-status-error = Mae eich ffurfweddiad cyfredol yn defnyddio ID allwedd <b>{ $key }</b>, sydd wedi dod i ben.
+openpgp-add-key-button =
+    .label = Ychwanegu Allwedd…
+    .accesskey = Y
+e2e-learn-more = Dysgu rhagor
+openpgp-keygen-success = Allwedd OpenPGP wedi'i chreu'n llwyddiannus!
+openpgp-keygen-import-success = Allweddi OpenPGP wedi'u mewnforio yn llwyddiannus!
+openpgp-keygen-external-success = ID Allwedd GnuPG Allanol wedi'i chadw!
+
+## OpenPGP Key selection area
+
+openpgp-radio-none =
+    .label = Dim
+openpgp-radio-none-desc = Peidiwch â defnyddio OpenPGP ar gyfer yr hunaniaeth hon.
+#   $key (String) - the expiration date of the OpenPGP key
+openpgp-radio-key-expires = Yn dod i ben ar: { $date }
+openpgp-key-expires-image =
+    .tooltiptext = Mae'r allwedd yn dod i ben o fewn 6 mis
+#   $key (String) - the expiration date of the OpenPGP key
+openpgp-radio-key-expired = Wedi dod i ben ar: { $date }
+openpgp-key-expired-image =
+    .tooltiptext = Daeth yr allwedd i ben
+openpgp-key-expand-section =
+    .tooltiptext = Rhagor o wybodaeth
+openpgp-key-revoke-title = Dirymu Allwedd
+openpgp-key-edit-title = Newid Allwedd OpenPGP
+openpgp-key-edit-date-title = Ymestyn Dyddiad Dod i Ben
+openpgp-manager-description = Defnyddiwch y Rheolwr Allweddi OpenPGP i weld a rheoli allweddi cyhoeddus eich gohebwyr a'r holl allweddi eraill nad ydynt wedi'u rhestru uchod.
+openpgp-manager-button =
+    .label = Rheolwr Allwedd OpenPGP
+    .accesskey = R
+openpgp-key-remove-external =
+    .label = Dileu ID Allwedd Allanol
+    .accesskey = D
+key-external-label = Allwedd GnuPG Allanol
+# Strings in keyDetailsDlg.xhtml
+key-type-public = allwedd gyhoeddus
+key-type-primary = allwedd gynradd
+key-type-subkey = is-allwedd
+key-type-pair = pâr o allweddi (allwedd gyfrinachol ac allwedd gyhoeddus)
+key-expiry-never = byth
+key-usage-encrypt = Amgryptio
+key-usage-sign = Llofnodi
+key-usage-certify = Tystio
+key-usage-authentication = Dilysu
+key-does-not-expire = Nid yw'r allwedd yn dod i ben
+key-expired-date = Daeth yr allwedd i ben ar { $keyExpiry }
+key-expired-simple = Mae'r allwedd wedi dod i ben
+key-revoked-simple = Mae'r allwedd wedi'i dirymu
+key-do-you-accept = Ydych chi'n derbyn yr allwedd hon ar gyfer gwirio llofnodion digidol ac ar gyfer amgryptio negeseuon?
+key-accept-warning = Peidiwch â derbyn allweddi twyllodrus. Defnyddiwch sianel gyfathrebu heblaw e-bost i wirio bysbrint allwedd eich gohebydd.
+# Strings enigmailMsgComposeOverlay.js
+cannot-use-own-key-because = Methu anfon y neges, oherwydd mae problem gyda'ch allwedd bersonol. { $problem }
+cannot-encrypt-because-missing = Methu anfon y neges hon gydag amgryptio pen-i-ben, oherwydd mae problemau gydag allweddi'r derbynwyr canlynol: { $problem }
+window-locked = Mae'r ffenestr gyfansoddi wedi'i chloi; anfon wedi'i ddiddymu
+# Strings in mimeDecrypt.jsm
+mime-decrypt-encrypted-part-attachment-label = Rhan o neges wedi'i hamgryptio
+mime-decrypt-encrypted-part-concealed-data = Mae hon yn rhan o neges wedi'i hamgryptio. Mae angen i chi ei hagor mewn ffenestr ar wahân trwy glicio ar yr atodiad.
+# Strings in keyserver.jsm
+keyserver-error-aborted = Ataliwyd
+keyserver-error-unknown = Digwyddodd gwall anhysbys
+keyserver-error-server-error = Adroddodd y gweinydd allweddi wall.
+keyserver-error-import-error = Wedi methu mewnforio'r allwedd wedi'i llwytho i lawr.
+keyserver-error-unavailable = Nid yw'r gweinydd allweddi ar gael.
+keyserver-error-security-error = Nid yw'r gweinydd allweddi'n cefnogi mynediad wedi'i amgryptio.
+keyserver-error-certificate-error = Nid yw tystysgrif y gweinydd allweddi'n ddilys.
+keyserver-error-unsupported = Nid yw'r gweinydd allweddi'n cael ei gynnal
+# Strings in mimeWkdHandler.jsm
+wkd-message-body-req =
+    Prosesodd eich darparwr e-bost eich cais i lwytho'ch allwedd gyhoeddus i fyny i Gyfeiriadur Allwedd Gwe OpenPGP.
+    Cadarnhewch i gwblhau cyhoeddi eich allwedd gyhoeddus.
+wkd-message-body-process =
+    E-bost yw hwn sy'n gysylltiedig â'r prosesu awtomatig i lwytho'ch allwedd gyhoeddus i fyny i Gyfeiriadur Allwedd Gwe OpenPGP.
+    Nid oes angen i chi gymryd unrhyw gamau â llaw ar hyn o bryd.
+# Strings in persistentCrypto.jsm
+converter-decrypt-body-failed =
+    Methu dadgryptio neges gyda'r pwnc
+    { $subject }.
+    Ydych chi am geisio eto gyda chyfrinair gwahanol neu a ydych chi am hepgor y neges?
+# Strings in gpg.jsm
+unknown-signing-alg = Algorithm llofnodi anhysbys (ID: { $id })
+unknown-hash-alg = Hash cryptograffig anhysbys (ID: { $id }
+# Strings in keyUsability.jsm
+expiry-key-expires-soon =
+    Bydd eich allwedd { $desc } yn dod i ben mewn llai na { $days } diwrnod.
+    Rydym yn argymell eich bod yn creu pâr o allweddi newydd ac yn ffurfweddu'r cyfrifon cyfatebol i'w ddefnyddio.
+expiry-keys-expire-soon =
+    Bydd eich allwedd { $desc } yn dod i ben mewn llai na { $days } diwrnod.
+    Rydym yn argymell eich bod yn creu allweddi newydd ac yn ffurfweddu'r cyfrifon cyfatebol i'w ddefnyddio.
+expiry-key-missing-owner-trust =
+    Mae eich allwedd gyfrinachol { $desc } yn fyr o ymddiriedaeth.
+    Rydym yn argymell eich bod yn gosod "Rydych chi'n dibynnu ar ardystiadau" i "eithaf" ym mhriodweddau'r allwedd.
+expiry-keys-missing-owner-trust =
+    Mae'ch allweddi cyfrinachol canlynol { $desc } yn fyr o ymddiriedaeth.
+    { $desc }.
+    Rydym yn argymell eich bod yn gosod "Rydych chi'n dibynnu ar ardystiadau" i "eithaf" ym mhriodweddau'r allwedd.
+expiry-open-key-manager = Agor Rheolwr Allweddi OpenPGP
+expiry-open-key-properties = Agor Priodweddau Allweddi
+# Strings filters.jsm
+filter-folder-required = Rhaid dewis ffolder targed.
+filter-decrypt-move-warn-experimental =
+    Rhybudd - gall y weithred hidlo "Dadgryptio yn barhaol" arwain at negeseuon wedi'u dinistrio.
+    Rydym yn argymell yn gryf eich bod yn gyntaf yn rhoi cynnig ar yr hidlydd "Creu Copi wedi'i ddadgryptio", profi'r canlyniad yn ofalus, a dim ond ar ôl i chi fod yn fodlon â'r canlyniad yn dechrau defnyddio'r hidlydd.
+filter-term-pgpencrypted-label = Amgryptio OpenPGP
+filter-key-required = Rhaid dewis allwedd derbynnydd.
+filter-key-not-found = Methu cnfod allwedd amgryptio ar gyfer '{ $desc }'.
+filter-warn-key-not-secret =
+    Rhybudd - mae'r weithred hidlo "Amgryptio i allwedd" yn disodli'r derbynwyr.
+    Os nad oes gennych yr allwedd gyfrinachol ar gyfer '{ $desc }' fyddwch chi ddim yn gallu darllen yr e-byst bellach.
+# Strings filtersWrapper.jsm
+filter-decrypt-move-label = Dadgryptio yn barhaol (OpenPGP)
+filter-decrypt-copy-label = Creu Copi wedi'i ddadgryptio (OpenPGP)
+filter-encrypt-label = Amgryptio i allwedd (OpenPGP)
+# Strings in enigmailKeyImportInfo.js
+import-info-title =
+    .title = Llwyddiant! Allweddi wedi'u mewnforio
+import-info-bits = Didau
+import-info-created = Crëwyd
+import-info-fpr = Bysbrint
+import-info-details = Gweld Manylion a rheoli derbyniad allweddi
+import-info-no-keys = Dim allweddi wedi'u mewnforio.
+# Strings in enigmailKeyManager.js
+import-from-clip = Hoffech chi fewnforio rhywfaint o allweddi o'r clipfwrdd?
+import-from-url = Llwytho allwedd gyhoeddus i lawr o'r URL hwn:
+copy-to-clipbrd-failed = Methu copïo'r allweddi hyn i'r clipfwrdd.
+copy-to-clipbrd-ok = Copïwyd allweddi i'r clipfwrdd
+delete-secret-key =
+    RHYBUDD: Rydych chi ar fin dileu allwedd gyfrinachol!
+    
+    Os byddwch yn dileu eich allwedd gyfrinachol, ni fydd modd i chi ddadgryptio unrhyw negeseuon sydd wedi'u hamgryptio ar gyfer yr allwedd honno bellach, ac ni fyddwch yn gallu ei dirymu.
+    
+    Ydych chi wir eisiau DILEU'R allwedd gyfrinachol a'r allwedd gyhoeddus
+    '{ $userId }'?
+delete-mix =
+    RHYBUDD: Rydych chi ar fin dileu allwedd gyfrinachol!
+    Os byddwch yn dileu eich allwedd gyfrinachol, ni fydd modd i chi ddadgryptio unrhyw negeseuon sydd wedi'u hamgryptio ar gyfer yr allwedd honno bellach.
+    Ydych chi wir eisiau DILEU'R allwedd gyfrinachol a'r un gyhoeddus?
+delete-pub-key =
+    Ydych chi eisiau dileu'r allwedd gyhoeddus
+    '{ $userId }'?
+delete-selected-pub-key = Ydych chi eisiau dileu'r allwedd gyhoeddus'?
+refresh-all-question = Nid ydych wedi dewis unrhyw allwedd. Hoffech chi adnewyddu POB allwedd?
+key-man-button-export-sec-key = &Allforio Allweddi Cyfrinachol
+key-man-button-export-pub-key = Allforion Allweddi &Cyhoeddus yn Unig
+key-man-button-refresh-all = Adnewyddu &Pob Allwedd
+key-man-loading-keys = Llwytho allweddi, arhoswch...
+ascii-armor-file = Ffeiliau Arfogaeth ASCII (* .asc)
+no-key-selected = Dylech ddewis o leiaf un allwedd er mwyn cyflawni'r weithred hon
+export-to-file = Allforio Allwedd Gyhoeddus i Ffeil
+export-keypair-to-file = Allforio Allwedd Gyfrinachol a Chyhoeddus i Ffeil
+export-secret-key = Ydych chi am gynnwys yr allwedd gyfrinachol yn y ffeil allwedd OpenPGP sydd wedi'i chadw?
+save-keys-ok = Cadwyd yr allweddi'n llwyddiannus
+save-keys-failed = Methodd cadw'r allweddi
+default-pub-key-filename = Allweddi cyhoeddus wedi'u hallforio
+default-pub-sec-key-filename = Copi wrth gefn o allweddi cyfrinachol
+refresh-key-warn = Rhybudd: yn dibynnu ar nifer yr allweddi a chyflymder y cysylltiad, gall adnewyddu'r holl allweddi fod yn broses eithaf hir!
+preview-failed = Methu darllen ffeil allwedd gyhoeddus.
+general-error = Gwall: { $reason }
+dlg-button-delete = &Dileu
+
+## Account settings export output
+
+openpgp-export-public-success = <b> Allforiwyd Allwedd Gyhoeddus yn llwyddiannus!</b>
+openpgp-export-public-fail = <b>Methu allforio'r allwedd gyhoeddus a ddewiswyd!</b>
+openpgp-export-secret-success = <b>Allforiwyd Allwedd Gyfrinachol yn llwyddiannus!</b>
+openpgp-export-secret-fail = <b>Methu allforio'r allwedd gyfrinachol a ddewiswyd!</b>
+# Strings in keyObj.jsm
+key-ring-pub-key-revoked = Mae'r allwedd { $userId } (ID allwedd { $keyId }) wedi'i dirymu.
+key-ring-pub-key-expired = Mae'r allwedd { $userId } (ID allwedd { $keyId }) wedi dod i ben.
+key-ring-key-disabled = Mae'r allwedd { $userId } (ID allwedd { $keyId }) wedi'i analluogi; nid oes modd ei defnyddio.
+key-ring-key-invalid = Nid yw'r allwedd { $userId } (ID allwedd { $keyId }) yn ddilys. Ystyriwch ei ddilysu'n gywir.
+key-ring-key-not-trusted = Nid yw'r allwedd { $userId } (ID allwedd { $keyId }) yn ddigon dibynadwy. Gosodwch lefel ymddiriedaeth eich allwedd i "eithaf" i'w defnyddio ar gyfer llofnodi.
+key-ring-no-secret-key = Nid yw'n ymddangos bod gennych yr allwedd gyfrinachol ar gyfer { $userId } (ID allwedd { $keyId }) ar eich cylch allweddi; nid oes modd i chi ddefnyddio'r allwedd ar gyfer llofnodi.
+key-ring-pub-key-not-for-signing = Nid oed modd defnyddio'r allwedd { $userId } (ID allweddl { $keyId } ar gyfer llofnodi.
+key-ring-pub-key-not-for-encryption = Nid oed modd defnyddio'r allwedd { $userId } (ID allweddl { $keyId } ar gyfer amgryptio.
+key-ring-sign-sub-keys-revoked = Mae'r holl is-allweddi lofnodi allwedd { $userId } (ID allweddl { $keyId }) yn cael eu dirymu.
+key-ring-sign-sub-keys-expired = Mae'r holl is-allweddi lofnodi allwedd { $userId } (ID allweddl { $keyId }) wedi dod i ben.
+key-ring-sign-sub-keys-unusable = Mae'r holl is-allweddi lofnodi allwedd { $userId } (ID allwedd { $keyId }) wedi eu dirymu, dod i ben neu fel arall.
+key-ring-enc-sub-keys-revoked = Mae pob is-allwedd amgryptio allwedd { $userId } (ID allwedd { $keyId }) yn cael ei ddirymu.
+key-ring-enc-sub-keys-expired = Mae pob is-allwedd amgryptio allwedd { $userId } (ID allwedd { $keyId }) wedi dod i ben.
+key-ring-enc-sub-keys-unusable = Mae pob is-allwedd amgryptio allwedd { $userId } (ID allwedd { $keyId }) wedi cael eu dirymu, wedi dod i ben neu fel arall.
+# Strings in gnupg-keylist.jsm
+keyring-photo = Llun
+user-att-photo = Priodoledd defnyddiwr (delwedd JPEG)
+# Strings in key.jsm
+already-revoked = Mae'r allwedd hon eisoes wedi'i dirymu.
+#   $identity (String) - the id and associated user identity of the key being revoked
+revoke-key-question =
+    Rydych chi ar fin dirymu'r allwedd '{ $identity }'.
+    Ni fydd modd i chi llofnodi gyda'r allwedd hon mwyach, ac ar ôl ei dosbarthu, ni fydd eraill yn gallu amgryptio gyda'r allwedd honno mwyach. Gallwch barhau i ddefnyddio'r allwedd i ddadgryptio hen negeseuon.
+    Ydych chi am barhau?
+#   $keyId (String) - the id of the key being revoked
+revoke-key-not-present =
+    Nid oes gennych allwedd (0x { $keyId }) sy'n cyfateb i'r dystysgrif ddirymu hon!
+    Os ydych wedi colli'ch allwedd, rhaid i chi ei fewnforio (e.e. o weinydd allweddi) cyn mewnforio'r dystysgrif ddirymu!
+#   $keyId (String) - the id of the key being revoked
+revoke-key-already-revoked = Mae'r allwedd 0x { $keyId } eisoes wedi'i dirymu.
+key-man-button-revoke-key = &Dirymu Allwedd
+openpgp-key-revoke-success = Dirymwyd yr allwedd yn llwyddiannus.
+after-revoke-info =
+    Mae'r allwedd wedi'i dirymu.
+    Rhannwch yr allwedd gyhoeddus hon eto, trwy ei hanfon trwy e-bost, neu trwy ei llwytho i weinyddion allweddi, i adael i eraill wybod eich bod wedi dirymu'ch allwedd.
+    Cyn gynted ag y bydd y feddalwedd sy'n cael ei ddefnyddio gan bobl eraill yn gwybod am y dirymiad, bydd yn rhoi'r gorau i ddefnyddio'ch hen allwedd.
+    Os ydych chi'n defnyddio allwedd newydd ar gyfer yr un cyfeiriad e-bost, a'ch bod chi'n atodi'r allwedd gyhoeddus newydd i e-byst rydych chi'n eu hanfon, yna bydd gwybodaeth am eich hen allwedd wedi'i dirymu yn cael ei chynnwys yn awtomatig.
+# Strings in keyRing.jsm & decryption.jsm
+key-man-button-import = &Mewnforio
+delete-key-title = Dileu Allwedd OpenPGP
+delete-external-key-title = Tynnwch yr Allwedd GnuPG Allanol
+delete-external-key-description = Ydych chi am dynnu'r ID yr allwedd GnuPG Allanol hwn?
+key-in-use-title = Allwedd OpenPGP sy'n cael ei defnyddio ar hyn o bryd
+delete-key-in-use-description = Methu parhau! Mae'r allwedd rydych wedi'i dewis i'w dileu yn cael ei defnyddio ar hyn o bryd gan yr hunaniaeth hon. Dewiswch allwedd wahanol, neu dewiswch ddim, a cheisiwch eto.
+revoke-key-in-use-description = Methu parhau! Mae'r allwedd rydych wedi'i dewis i'w dileu yn cael ei defnyddio ar hyn o bryd gan yr hunaniaeth hon. Dewiswch allwedd wahanol, neu dewiswch ddim, a cheisiwch eto.
+# Strings used in errorHandling.jsm
+key-error-key-spec-not-found = Nid oes modd cydweddu'r cyfeiriad e-bost '{ $keySpec }' ag allwedd ar eich cylch allweddi.
+key-error-key-id-not-found = Nid oes modd dod o hyd i ID yr allwedd wedi'i ffurfweddu '{ $keySpec }' ar eich cylch allweddi.
+key-error-not-accepted-as-personal = Nid ydych wedi cadarnhau mai'r allwedd gydag ID '{ $keySpec }' yw eich allwedd bersonol.
+# Strings used in enigmailKeyManager.js & windows.jsm
+need-online = Nid yw'r swyddogaeth rydych chi wedi'i dewis ar gael yn y modd all-lein. Ewch ar-lein a rhoi cynnig arall arni.
+# Strings used in keyRing.jsm & keyLookupHelper.jsm
+no-key-found = Nid oeddwn yn gallu canfod unrhyw allwedd sy'n cyfateb i'r meini prawf chwilio penodol yna.
+# Strings used in keyRing.jsm & GnuPGCryptoAPI.jsm
+fail-key-extract = Gwall - methodd y gorchymyn echdynnu allwedd
+# Strings used in keyRing.jsm
+fail-cancel = Gwall - Allwedd yn cael ei ddiddymu gan y defnyddiwr
+not-first-block = Gwall - Y bloc OpenPGP cyntaf nid bloc allwedd gyhoeddus
+import-key-confirm = Mewnforio allwedd(i) cyhoeddus wedi'u mewnblannu yn y neges?
+fail-key-import = Gwall - methodd mewnforio allweddi
+file-write-failed = Methwyd ysgrifennu at ffeil { $output }
+no-pgp-block = Gwall - Heb ddarganfod bloc data arfogaeth dilys OpenPGP
+confirm-permissive-import = Methodd y mewnforio. Efallai bod yr allwedd rydych chi'n ceisio ei fewnforio yn llygredig neu'n defnyddio priodoleddau anhysbys. Hoffech chi geisio mewnforio'r rhannau sy'n gywir? Gall hyn arwain at fewnforio allweddi anghyflawn ac nad oes modd eu defnyddio.
+# Strings used in trust.jsm
+key-valid-unknown = anhysbys
+key-valid-invalid = annilys
+key-valid-disabled = analluogwyd
+key-valid-revoked = dirymwyd
+key-valid-expired = daeth i ben
+key-trust-untrusted = di-ymddiried
+key-trust-marginal = ymylol
+key-trust-full = ymddiried ynddo
+key-trust-ultimate = eithaf
+key-trust-group = (grŵp)
+# Strings used in commonWorkflows.js
+import-key-file = Mewnforio Ffeil Allwedd OpenPGP
+import-rev-file = Mewnforio Ffeil Dirymu OpenPGP
+gnupg-file = Ffeiliau GnuPG
+import-keys-failed = Methodd mewnforio'r allweddi
+passphrase-prompt = Rhowch yr cyfrinymadrodd sy'n datgloi'r allwedd ganlynol: { $key }
+file-to-big-to-import = Mae'r ffeil hon yn rhy fawr. Peidiwch â mewnforio set fawr o allweddi ar unwaith.
+# Strings used in enigmailKeygen.js
+save-revoke-cert-as = Creu a Chadw Tystysgrif Dirymu
+revoke-cert-ok = Mae'r dystysgrif ddirymu wedi'i chreu'n llwyddiannus. Gallwch ei ddefnyddio i annilysu eich allwedd gyhoeddus, e.e. rhag ofn y byddwch yn colli'ch allwedd gyfrinachol.
+revoke-cert-failed = Nid oedd modd creu'r dystysgrif ddirymu.
+gen-going = Wrthi'n cynhyrchu allwedd!
+keygen-missing-user-name = Nid oes enw wedi'i nodi ar gyfer y cyfrif/hunaniaeth hon. Rhowch werth yn y maes   "Eich enw" yn yng ngosodiadau'r cyfrif.
+expiry-too-short = Rhaid i'ch allwedd fod yn ddilys am o leiaf un diwrnod.
+expiry-too-long = Nid oes modd i chi greu allwedd sy'n dod i ben mewn mwy na 100 mlynedd.
+key-confirm = Cynhyrchu allwedd gyhoeddus a chyfrinachol ar gyfer '{ $id }'?
+key-man-button-generate-key = &Cynhyrchu Allwedd
+key-abort = Atal cynhyrchu allwedd?
+key-man-button-generate-key-abort = &Atal Cynhyrchu Allwedd?
+key-man-button-generate-key-continue = &Parhau i Gynhyrchu Allweddi
+
+# Strings used in enigmailMessengerOverlay.js
+
+failed-decrypt = Gwall - methodd y dadgryptio
+fix-broken-exchange-msg-failed = Heb lwyddo i atgyweirio neges.
+attachment-no-match-from-signature = Methu cydweddu ffeil llofnod '{ $attachment }' ag atodiad
+attachment-no-match-to-signature = Methu cydweddu ffeil llofnod '{ $attachment }' â ffeil llofnod
+signature-verified-ok = Gwiriwyd y llofnod ar gyfer atodiad { $attachment } yn llwyddiannus
+signature-verify-failed = Methwyd gwirio y llofnod ar gyfer atodiad { $attachment }
+decrypt-ok-no-sig =
+    Rhybudd
+    Bu'r dadgryptio yn llwyddiant ond nid oedd modd gwirio'r llofnod yn iawn
+msg-ovl-button-cont-anyway = &Parhau Beth bynnag
+enig-content-note = *Nid yw atodiadau i'r neges hon wedi'u llofnodi na'u hamgryptio *
+# Strings used in enigmailMsgComposeOverlay.js
+msg-compose-button-send = &Anfon Neges
+msg-compose-details-button-label = Manylion…
+msg-compose-details-button-access-key = M
+send-aborted = Ataliwyd y weithred o anfon.
+key-not-trusted = Dim digon o ymddiriedaeth ar gyfer allwedd '{ $key }'
+key-not-found = Heb ddarganfod allwedd '{ $key }'
+key-revoked = Allwedd '{ $key }' wedi'i ddirymu
+key-expired = Allwedd '{ $key }' wedi dod i ben
+msg-compose-internal-error = Digwyddodd gwall mewnol.
+keys-to-export = Dewiswch Allweddi OpenPGP i'w Mewnosod
+msg-compose-partially-encrypted-inlinePGP =
+    Roedd y neges rydych chi'n ymateb iddi yn cynnwys rhannau heb eu hamgryptio ac wedi'u hamgryptio. Os nad oedd yr anfonwr yn gallu dadgryptio rhai rhannau o'r neges yn wreiddiol, efallai eich bod yn gollwng gwybodaeth gyfrinachol nad oedd yr anfonwr yn gallu dadgryptio ei hun yn wreiddiol.
+    Ystyriwch dynnu'r holl destun a ddyfynnwyd o'ch ateb i'r anfonwr hwn.
+msg-compose-cannot-save-draft = Gwall wrth gadw drafft
+msg-compose-partially-encrypted-short = Gwyliwch rhag gollwng gwybodaeth sensitif - e-bost wedi'i amgryptio'n rhannol.
+quoted-printable-warn =
+    Rydych wedi galluogi amgodio 'dyfyniad-argraffadwy' ar gyfer anfon negeseuon. Gall hyn arwain at ddadgryptio anghywir a/neu ddilysu'ch neges.
+    Ydych chi am ddiffodd anfon negeseuon 'dyfyniad-argraffadwy' nawr?
+minimal-line-wrapping =
+    Rydych chi wedi gosod lapio llinell i nodau { $width }. Ar gyfer amgryptio a/neu lofnodi cywir, mae angen i'r gwerth hwn fod yn 68 o leiaf.
+    Ydych chi am newid amlapio llinell i 68 nod nawr?
+sending-hidden-rcpt = Nid oes modd defnyddio derbynwyr BCC (copi dall) wrth anfon neges wedi'i hamgryptio. I anfon y neges amgryptiedig hon, naill ai tynnwch y derbynwyr BCC neu eu symud i'r maes CC.
+sending-news =
+    Ataliwyd gweithrediad anfon wedi'i amgryptio.
+    Nid oes modd amgryptio'r neges hon oherwydd bod derbynwyr grwpiau newyddion. Ail-anfonwch y neges heb amgryptio.
+send-to-news-warning =
+    Rhybudd: rydych chi ar fin anfon e-bost wedi'i amgryptio i grŵp newyddion.
+    Nid yw hyn yn cael ei annog oherwydd nad yw ond yn gwneud synnwyr os yw pob aelod o'r grŵp yn gallu dadgryptio'r neges, h.y. mae angen amgryptio'r neges gydag allweddi holl gyfranogwyr y grŵp. Anfonwch y neges hon dim ond os ydych chi'n gwybod yn union beth rydych chi'n ei wneud.
+    Parhau?
+save-attachment-header = Cadw atodiad wedi'i ddadgryptio
+no-temp-dir =
+    Methu dod o hyd i gyfeiriadur dros dro i ysgrifennu ato
+    Gosodwch y newidyn amgylchedd TEMP
+possibly-pgp-mime = Neges wedi'i hamgryptio neu wedi'i llofnodi gan PGP/MIME o bosibl; defnyddiwch swyddogaeth 'Dadgryptio/Gwirio' i wirio
+cannot-send-sig-because-no-own-key = Methu llofnodi'r neges hon yn ddigidol, oherwydd nid ydych eto wedi ffurfweddu amgryptio pen-i-ben ar gyfer <{ $key }>
+cannot-send-enc-because-no-own-key = Methu anfon y neges hon wedi'i hamgryptio, oherwydd nid ydych eto wedi ffurfweddu amgryptio pen-i-ben ar gyfer <{ $key }>
+# Strings used in decryption.jsm
+do-import-multiple =
+    Mewnforio'r allweddi canlynol?
+    { $key }
+do-import-one = Mewnforio { $name } ({ $id })?
+cant-import = Gwall wrth fewnforio allwedd gyhoeddus
+unverified-reply = Mae'n debyg bod rhan neges wedi'i mewnoli (ateb) wedi'i haddasu
+key-in-message-body = Wedi canfod allwedd yng nghorff y neges. Cliciwch 'Allwedd Mewnforio' i fewnforio'r allwedd
+sig-mismatch = Gwall - Camgydweddiad llofnod
+invalid-email = Gwall - cyfeiriad(au) e-bost annilys
+attachment-pgp-key =
+    Mae'n ymddangos bod yr atodiad '{ $name }' rydych chi'n ei agor yn ffeil allwedd OpenPGP.
+    Cliciwch 'Mewnforio' i fewnforio'r allweddi sydd wedi'u cynnwys neu 'Golwg' i weld cynnwys y ffeil mewn ffenestr porwr
+dlg-button-view = &Golwg
+# Strings used in enigmailMsgHdrViewOverlay.js
+decrypted-msg-with-format-error = Neges wedi'i dadgryptio (fformat e-bost PGP wedi'i dorri wedi'i adfer yn ôl pob tebyg wedi'i achosi gan hen weinydd Exchange, fel na fyddai'r canlyniad yn berffaith i'w ddarllen o bosibl)
+# Strings used in encryption.jsm
+not-required = Gwall - nid oes angen amgryptio
+# Strings used in windows.jsm
+no-photo-available = Dim Llun ar gael
+error-photo-path-not-readable = Nid yw llwybr llun '{ $photo }' yn ddarllenadwy
+debug-log-title = Cofnod Dadfygio OpenPGP
+# Strings used in dialog.jsm
+repeat-prefix = Bydd y rhybudd hwn yn ailadrodd { $count }
+repeat-suffix-singular = rhagor o amser.
+repeat-suffix-plural = rhagor o amser.
+no-repeat = Ni fydd y rhybudd hwn yn cael ei ddangos eto.
+dlg-keep-setting = Cofiwch fy ateb a pheidiwch â gofyn imi eto
+dlg-button-ok = &IAWN
+dlg-button-close = &Cau
+dlg-button-cancel = &Diddymu
+dlg-no-prompt = Peidio dangos y blwch deialog eto.
+enig-prompt = Anogwr OpenPGP
+enig-confirm = Cadarnhad OpenPGP
+enig-alert = Rhybudd OpenPGP
+enig-info = Manylion OpenPGP
+# Strings used in persistentCrypto.jsm
+dlg-button-retry = &Ceisio eto
+dlg-button-skip = &Hepgor
+# Strings used in enigmailCommon.js
+enig-error = Gwall OpenPGP
+enig-alert-title =
+    .title = Rhybudd OpenPGP
diff --git a/l10n-cy/mail/messenger/otr/add-finger.ftl b/l10n-cy/mail/messenger/otr/add-finger.ftl
new file mode 100644
index 0000000000..eb5e0fefd9
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/add-finger.ftl
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+otr-add-finger =
+    .title = Ychwanegu bysbrint Allwedd OTR
+
+# Variables:
+#   $name (String) - name of a chat contact person
+# Do not translate 'OTR' (name of an encryption protocol)
+otr-add-finger-description = Rhowch bysbrint allwedd OTR ar gyfer { $name }.
+
+otr-add-finger-fingerprint = Bysbrint
+otr-add-finger-tooltip-error = Nod annilys wedi'i roi. Dim ond llythrennau ABCDEF a rhifau sy'n cael eu caniatáu
+
+otr-add-finger-input =
+    .placeholder = Bysbrint allwedd OTR 40 nod o hyd
diff --git a/l10n-cy/mail/messenger/otr/am-im-otr.ftl b/l10n-cy/mail/messenger/otr/am-im-otr.ftl
new file mode 100644
index 0000000000..85429a9ac9
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/am-im-otr.ftl
@@ -0,0 +1,28 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+account-encryption =
+    .label = Amgryptio Pen-i-Ben
+account-otr-label = Negeseuon Dim Cofnod (OTR)
+account-otr-description = Mae { -brand-short-name } yn cefnogi amgryptio sgyrsiau un i un o'r dechrau i'r diwedd. Mae hyn yn atal trydydd partïon rhag clustfeinio ar sgyrsiau. Dim ond pan fydd y person arall hefyd yn defnyddio meddalwedd sy'n cefnogi OTR y mae modd defnyddio amgryptio o'r dechrau i'r diwedd.
+otr-encryption-title = Amgryptio wedi'i Wirio
+otr-encryption-caption = Er mwyn galluogi pobl eraill i wirio'ch hunaniaeth mewn sgyrsiau OTR, rhannwch eich bysbrintiau OTR eich hun gan ddefnyddio sianel gyfathrebu allanol (tu-allan-i'r-band).
+otr-fingerprint-label = Eich Bysbrint:
+view-fingerprint-button =
+    .label = Rheoli Bysbrintiau Cysylltiadau
+    .accesskey = R
+otr-settings-title = Gosodiadau OTR
+otr-log =
+    .label = Cynnwys negeseuon wedi'u hamgryptio OTR mewn cofnodion sgwrsio
+otr-requireEncryption =
+    .label = Angen amgryptio pen-i-ben ar gyfer sgyrsiau un i un
+otr-require-encryption-info =
+    Wrth ofyn am amgryptio negeseuon o ben-i-ben, ni fydd negeseuon mewn sgyrsiau
+    un i un yn cael eu hanfon oni bai bod modd eu hamgryptio. Ni fydd negeseuon wedi'u
+    derbyn heb eu hamgryptio yn cael eu dangos fel rhan o'r sgwrs arferol, na'u cofnodi chwaith.
+otr-verifyNudge =
+    .label = Atgoffa bob tro i wirio cyswllt heb ei wirio
+
+otr-notYetAvailable = ddim ar gael eto
+
diff --git a/l10n-cy/mail/messenger/otr/auth.ftl b/l10n-cy/mail/messenger/otr/auth.ftl
new file mode 100644
index 0000000000..c21f007a19
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/auth.ftl
@@ -0,0 +1,59 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+otr-auth =
+    .title = Gwirio hunaniaeth cyswllt
+    .buttonlabelaccept = Gwirio
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+auth-title = Gwirio hunaniaeth { $name }
+
+# Variables:
+#   $own_name (String) - the user's own screen name
+auth-your-fp-value = Bysbrint i chi, { $own_name }:
+
+# Variables:
+#   $their_name (String) - the screen name of a chat contact
+auth-their-fp-value = Bysbrint i { $their_name }:
+
+auth-help = Mae gwirio hunaniaeth cyswllt yn helpu i sicrhau bod y sgwrs yn wirioneddol breifat, gan ei gwneud yn anodd iawn i drydydd parti glustfeinio neu drin y sgwrs.
+auth-helpTitle = Cymorth dilysu
+
+auth-questionReceived = Dyma'r cwestiwn sy'n cael ei ofyn gan eich cyswllt:
+
+auth-yes =
+    .label = Iawn
+
+auth-no =
+    .label = Na
+
+auth-verified = Rwyf wedi gwirio mai hwn yw'r bysprint cywir mewn gwirionedd.
+
+auth-manualVerification = Gwirio bysprintiau â llaw
+auth-questionAndAnswer = Cwestiwn ac ateb
+auth-sharedSecret = Cyfrinach wedi'i rannu
+
+auth-manualVerification-label =
+    .label = { auth-manualVerification }
+
+auth-questionAndAnswer-label =
+    .label = { auth-questionAndAnswer }
+
+auth-sharedSecret-label =
+    .label = { auth-sharedSecret }
+
+auth-manualInstruction = Cysylltwch â'ch partner sgwrsio arfaethedig trwy ryw sianel ddilys arall, fel e-bost wedi'i lofnodi gan OpenPGP neu dros y ffôn. Fe ddylech chi ddweud wrth eich gilydd beth yw eich bysbrintiau.  (Mae bysbrintiau yn wiriad sy'n adnabod allwedd amgryptio.) Os yw'r bysprintiau yn cyfateb, dylech nodi yn y dialog isod eich bod wedi gwirio'r bysprint.
+
+auth-how = Sut hoffech chi wirio hunaniaeth eich cyswllt?
+
+auth-qaInstruction = Meddyliwch am gwestiwn y mae'r ateb yn hysbys i chi a'ch cyswllt yn unig. Rhowch y cwestiwn a'r ateb, yna arhoswch i'ch cyswllt roi'r ateb. Os nad yw'r atebion yn cydweddu, gall y sianel gyfathrebu rydych chi'n ei defnyddio fod o dan wyliadwriaeth.
+
+auth-secretInstruction = Meddyliwch am gyfrinach sy'n hysbys i chi a'ch cyswllt yn unig. Peidiwch â defnyddio'r un cysylltiad Rhyngrwyd i gyfnewid y gyfrinach. Rhowch y gyfrinach, yna arhoswch i'ch cyswllt ei roi. Os nad yw'r cyfrinachau yn cyfateb, gall y sianel gyfathrebu rydych chi'n ei defnyddio fod o dan wyliadwriaeth.
+
+auth-question = Rhowch gwestiwn:
+
+auth-answer = Rhowch yr ateb (sensitif i faint):
+
+auth-secret = Rhowch y gyfrinach:
diff --git a/l10n-cy/mail/messenger/otr/chat.ftl b/l10n-cy/mail/messenger/otr/chat.ftl
new file mode 100644
index 0000000000..8ca2af4cba
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/chat.ftl
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+state-label = Statws Amgryptio:
+
+start-text = Cychwynnwch sgwrs wedi'i hamgryptio
+
+start-label =
+    .label = { start-text }
+
+start-tooltip =
+    .tooltiptext = { start-text }
+
+end-label =
+    .label = Gorffennwch y sgwrs wedi'i hamgryptio
+
+auth-label =
+    .label = Gwiriwch hunaniaeth eich cyswllt
diff --git a/l10n-cy/mail/messenger/otr/finger-sync.ftl b/l10n-cy/mail/messenger/otr/finger-sync.ftl
new file mode 100644
index 0000000000..2b8b76e066
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/finger-sync.ftl
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+finger-yes = Gwiriwyd
+finger-no = Heb ei wirio
+
+finger-subset-title = Tynnu Bysbrintiau
+finger-subset-message = Nid oedd modd tynnu o leiaf un bysbrint, oherwydd ar hyn o bryd mae'r allwedd gyfatebol yn cael ei defnyddio mewn sgwrs weithredol.
+
+finger-remove-all-title = Tynnu'r Holl Bysbrintiau
+finger-remove-all-message = Ydych chi'n siŵr eich bod chi am dynnu'r holl bysbrintiau a welwyd o'r blaen? Bydd yr holl wiriadau hunaniaeth OTR blaenorol yn cael eu colli.
diff --git a/l10n-cy/mail/messenger/otr/finger.ftl b/l10n-cy/mail/messenger/otr/finger.ftl
new file mode 100644
index 0000000000..dae42dbe71
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/finger.ftl
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+otr-finger =
+    .buttonlabelaccept = Cau
+    .title = Bysprintiau OTR Blaenorol
+
+finger-intro = Bysprintiau allweddol OTR o sgyrsiau amgryptiedig blaenorol o'r pen-i-ben.
+
+finger-screenName =
+    .label = Cyswllt
+finger-verified =
+    .label = Statws Gwirio
+finger-fingerprint =
+    .label = Bysbrint
+
+finger-remove =
+    .label = Tynnu'r Dewis
+
+finger-remove-all =
+    .label = Tynnu'r Cyfan
diff --git a/l10n-cy/mail/messenger/otr/otr.ftl b/l10n-cy/mail/messenger/otr/otr.ftl
new file mode 100644
index 0000000000..8439306601
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/otr.ftl
@@ -0,0 +1,97 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-encryption_required_part1 = Fe wnaethoch geisio anfon neges heb ei hamgryptio at { $name }. Fel polisi, nid yw negeseuon heb eu hamgryptio'n cael eu caniatáu.
+
+msgevent-encryption_required_part2 = Yn ceisio cychwyn sgwrs breifat. Bydd eich neges yn cael ei ail anfon pan fydd y sgwrs breifat yn cychwyn.
+msgevent-encryption_error = Digwyddodd gwall wrth amgryptio'ch neges. Nid yw'r neges wedi'i hanfon.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-connection_ended = Mae { $name } eisoes wedi cau eu cysylltiad wedi'i amgryptio â chi. Er mwyn osgoi eich bod yn anfon neges heb amgryptio ar ddamwain, nid yw eich neges wedi ei hanfon. Gorffennwch eich sgwrs wedi'i hamgryptio, neu ail gychwynnwch hi.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-setup_error = Digwyddodd gwall wrth drefnu sgwrs breifat gyda { $name }.
+
+# Do not translate 'OTR' (name of an encryption protocol)
+msgevent-msg_reflected = Rydych yn derbyn eich negeseuon OTR eich hun. Rydych naill ai'n ceisio siarad â chi'ch hun, neu mae rhywun yn adlewyrchu'ch negeseuon yn ôl arnoch chi.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-msg_resent = Cafodd y neges olaf at { $name } ei hail anfon.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-rcvdmsg_not_private = Mae'r neges amgryptiedig a dderbyniwyd gan { $name } yn annarllenadwy, gan nad ydych yn cyfathrebu'n breifat ar hyn o bryd.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-rcvdmsg_unreadable = Cawsoch neges amgryptiedig annarllenadwy gan { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-rcvdmsg_malformed = Cawsoch neges ddata wedi'i hanffurfio gan { $name }.
+
+# A Heartbeat is a technical message used to keep a connection alive.
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-log_heartbeat_rcvd = Curiad calon wedi'i dderbyn gan { $name }.
+
+# A Heartbeat is a technical message used to keep a connection alive.
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-log_heartbeat_sent = Curiad calon wedi'i anfon at { $name }.
+
+# Do not translate 'OTR' (name of an encryption protocol)
+msgevent-rcvdmsg_general_err = Digwyddodd gwall annisgwyl wrth geisio diogelu'ch sgwrs gan ddefnyddio OTR.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+#   $msg (string) - the message that was received.
+msgevent-rcvdmsg_unencrypted = Nid yw'r neges ganlynol a dderbyniwyd gan { $name } wedi'i hamgryptio: { $msg }
+
+# Do not translate 'OTR' (name of an encryption protocol)
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-rcvdmsg_unrecognized = Cawsoch neges OTR heb ei hadnabod gan { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+msgevent-rcvdmsg_for_other_instance = Mae { $name } wedi anfon neges a fwriadwyd ar gyfer sesiwn wahanol. Os ydych wedi mewngofnodi sawl gwaith, efallai y bydd sesiwn arall wedi derbyn y neges.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+context-gone_secure_private = Cychwynnodd sgwrs breifat gyda { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+context-gone_secure_unverified = Cychwynnodd sgwrs breifat heb ei gwirio gyda { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+context-still_secure = Adnewyddwyd y sgwrs wedi'i hamgryptio yn llwyddiannus gyda { $name }.
+
+error-enc = Digwyddodd gwall wrth amgryptio'r neges.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+error-not_priv = Rydych wedi anfon data wedi'i amgryptio at { $name }, nad oedd yn ei ddisgwyl.
+
+error-unreadable = Rydych wedi trosglwyddo neges annarllenadwy wedi'i hamgryptio.
+error-malformed = Rydych wedi trosglwyddo neges ddata wedi'i hanffurfio.
+
+resent = [ail anfon]
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+tlv-disconnected = Mae { $name } wedi dod â'u sgwrs wedi'i hamgryptio gyda chi i ben; dylech wneud yr un peth.
+
+# Do not translate "Off-the-Record" and "OTR" which is the name of an encryption protocol
+# Make sure that this string does NOT contain any numbers, e.g. like "3".
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+query-msg = Mae { $name } wedi gofyn am sgwrs di-gofnod wedi'i hamgryptio (OTR). Fodd bynnag, nid oes gennych ategyn i gefnogi hynny. Gweler https://en.wikipedia.org/wiki/Off-the-Record_Messaging i gael mwy o wybodaeth.
diff --git a/l10n-cy/mail/messenger/otr/otrUI.ftl b/l10n-cy/mail/messenger/otr/otrUI.ftl
new file mode 100644
index 0000000000..6869a0886b
--- /dev/null
+++ b/l10n-cy/mail/messenger/otr/otrUI.ftl
@@ -0,0 +1,86 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+start-label = Cychwyn sgwrs wedi'i hamgryptio
+refresh-label = Adnewyddu sgwrs wedi'i hamgryptio
+auth-label = Gwirio hunaniaeth eich cyswllt
+reauth-label = Ail wirio hunaniaeth eich cyswllt
+
+auth-cancel = Diddymu
+auth-cancelAccessKey = D
+
+auth-error = Digwyddodd gwall wrth wirio hunaniaeth eich cyswllt.
+auth-success = Gwirio hunaniaeth eich cyswllt wedi'i gwblhau'n llwyddiannus.
+auth-successThem = Mae eich cyswllt wedi gwirio'ch hunaniaeth yn llwyddiannus. Efallai yr hoffech chi wirio eu hunaniaeth hefyd trwy ofyn eich cwestiwn chi.
+auth-fail = Wedi methu gwirio hunaniaeth eich cyswllt.
+auth-waiting = Yn aros i'r cyswllt gwblhau'r gwiriad...
+
+finger-verify = Gwirio
+finger-verify-accessKey = G
+
+# Do not translate 'OTR' (name of an encryption protocol)
+buddycontextmenu-label = Ychwanegu Bysbrint OTR
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+alert-start = Yn ceisio cychwyn sgwrs wedi'i hamgryptio gyda { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+alert-refresh = Yn ceisio adnewyddu'r sgwrs wedi'i hamgryptio gyda { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+alert-gone_insecure = Daeth y sgwrs wedi'i hamgryptio gyda { $name } i ben.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+finger-unseen = Nid yw hunaniaeth { $name } wedi'i wirio eto. Nid yw'n bosibl i glustfeinio'n achlysurol, ond gyda pheth ymdrech gallai rhywun fod yn gwrando. Rhwystrwch  wyliadwriaeth trwy wirio hunaniaeth y cyswllt hwn.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+finger-seen = Mae { $name } yn cysylltu â chi o gyfrifiadur heb ei adnabod. Nid yw'n bosibl clustfeinio'n achlysurol, ond gyda pheth ymdrech gall rhywun fod yn gwrando. Rhwystrwch wyliadwriaeth trwy wirio hunaniaeth y cyswllt hwn.
+
+state-not_private = Nid yw'r sgwrs gyfredol yn breifat.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+state-unverified = Mae'r sgwrs gyfredol wedi'i hamgryptio ond nid yn breifat, gan nad yw hunaniaeth { $name } wedi'i gwirio eto.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+state-private = Mae hunaniaeth { $name } wedi'i wirio. Mae'r sgwrs gyfredol wedi'i hamgryptio ac yn breifat.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+state-finished = Mae { $name } wedi dod â'u sgwrs wedi'i hamgryptio gyda chi i ben; dylech wneud yr un peth.
+
+state-not_private-label = Anniogel
+state-unverified-label = Heb ei wirio
+state-private-label = Preifat
+state-finished-label = Wedi gorffen
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+verify-request = Gofynnodd { $name } i gael dilysu'ch hunaniaeth.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+afterauth-private = Rydych wedi gwirio hunaniaeth { $name }.
+
+# Variables:
+#   $name (String) - the screen name of a chat contact person
+afterauth-unverified = Nid yw hunaniaeth { $name } wedi'i wirio.
+
+verify-title = Gwirio hunaniaeth eich cyswllt
+error-title = Gwall
+success-title = Amgryptio Pen-i-Ben
+successThem-title = Gwirio hunaniaeth eich cyswllt
+fail-title = Methu gwirio
+waiting-title = Cais dilysu wedi'i anfon
+
+# Do not translate 'OTR' (name of an encryption protocol)
+# Variables:
+#   $error (String) - contains an error message that describes the cause of the failure
+otr-genkey-failed = Methodd cynhyrchu allwedd breifat OTR: { $error }
diff --git a/l10n-cy/mail/messenger/policies/aboutPolicies.ftl b/l10n-cy/mail/messenger/policies/aboutPolicies.ftl
new file mode 100644
index 0000000000..fb4f39bd49
--- /dev/null
+++ b/l10n-cy/mail/messenger/policies/aboutPolicies.ftl
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-policies-title = Polisïau Menter
+
+# 'Active' is used to describe the policies that are currently active
+active-policies-tab = Gweithredol
+errors-tab = Gwallau
+documentation-tab = Dogfennaeth
+
+no-specified-policies-message = Mae'r gwasanaeth Polisïau Menter yn weithredol ond nid oes unrhyw bolisïau wedi'u galluogi.
+inactive-message = Mae'r gwasanaeth Polisïau Menter yn anweithredol.
+
+policy-name = Enw'r Polisi
+policy-value = Gwerth Polisi
+policy-errors = Gwallau Polisi
diff --git a/l10n-cy/mail/messenger/policies/policies-descriptions.ftl b/l10n-cy/mail/messenger/policies/policies-descriptions.ftl
new file mode 100644
index 0000000000..ea6f880fa2
--- /dev/null
+++ b/l10n-cy/mail/messenger/policies/policies-descriptions.ftl
@@ -0,0 +1,147 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## The Enterprise Policies feature is aimed at system administrators
+## who want to deploy these settings across several Thunderbird installations
+## all at once. This is traditionally done through the Windows Group Policy
+## feature, but the system also supports other forms of deployment.
+## These are short descriptions for individual policies, to be displayed
+## in the documentation section in about:policies.
+
+policy-3rdparty = Gosod polisïau y gall WebExtensions gael mynediad atyn nhw trwy chrome.storage.managed.
+
+policy-AppAutoUpdate = Galluogi neu analluogi diweddariad rhaglen awtomatig.
+
+policy-AppUpdateURL = Gosod URL diweddaru ap cyfaddas.
+
+policy-Authentication = Ffurfweddu dilysu integredig ar gyfer gwefannau sy'n ei gefnogi.
+
+policy-BlockAboutAddons = Rhwystro mynediad i'r Rheolwr Ychwanegion (about:addons).
+
+policy-BlockAboutConfig = Rhwystro mynediad i dudalen about:config.
+
+policy-BlockAboutProfiles = Rhwystro mynediad i dudalen about:profiles.
+
+policy-BlockAboutSupport = Rhwystro mynediad i dudalen about:support.
+
+policy-CaptivePortal = Galluogi neu analluogi cefnogaeth porth caeth.
+
+policy-CertificatesDescription = Ychwanegu dystysgrifau neu ddefnyddio dystysgrifau mewnol.
+
+policy-Cookies = Caniatáu neu rwystro gwefannau rhag gosod cwcis.
+
+policy-DisabledCiphers = Analluogi seifferau.
+
+policy-DefaultDownloadDirectory = Gosod y cyfeiriadur llwytho i lawr rhagosodedig.
+
+policy-DisableAppUpdate = Rhwystro { -brand-short-name } rhag diweddaru.
+
+policy-DisableDefaultClientAgent = Atal asiant y cleient rhagosodedig rhag cymryd unrhyw gamau. Dim ond yn berthnasol i Windows; nid oes gan lwyfannau eraill yr asiant.
+
+policy-DisableDeveloperTools = Rhwystro mynediad i offer datblygwr.
+
+policy-DisableFeedbackCommands = Analluogi gorchmynion anfon adborth o'r ddewislen Cymorth (Cyflwyno Adborth ac Adrodd ar Wefan Dwyllodrus).
+
+policy-DisableForgetButton = Rhwystro mynediad i'r botwm Anghofio.
+
+policy-DisableFormHistory = Peidio cofio chwilio a hanes ffurflenni.
+
+policy-DisableMasterPasswordCreation = Os true, nid oes modd creu prif gyfrinair.
+
+policy-DisablePasswordReveal = Peidio gadael i gyfrineiriau gael eu datgelu mewn mewngofnodion wedi'u cadw.
+
+policy-DisableProfileImport = Analluogi'r gorchymyn dewislen i Fewnforio data o raglen arall.
+
+policy-DisableSafeMode = Analluogi'r nodwedd i ailgychwyn yn y Modd Diogel. Sylw: dim ond drwy Bolisi Grŵp Windows y mae modd analluogi'r defnydd o fysell Shift i fynd i'r Modd Diogel.
+
+policy-DisableSecurityBypass = Rhwystro'r defnyddiwr rhag osgoi rhai rhybuddion diogelwch.
+
+policy-DisableSystemAddonUpdate = Rhwystro { -brand-short-name } rhag gosod a diweddaru ychwanegion y system.
+
+policy-DisableTelemetry = Diffodd Telemetreg.
+
+policy-DisplayMenuBar = Dangos y Bar Dewislen drwy ragosodiad.
+
+policy-DNSOverHTTPS = FFurfweddu DNS dros HTTPS
+
+policy-DontCheckDefaultClient = Analluogi gwirio am gleient rhagosodedig wrth gychwyn.
+
+policy-DownloadDirectory = Gosod a chloi'r cyfeiriadur llwytho i lawr.
+
+# “lock” means that the user won’t be able to change this setting
+policy-EnableTrackingProtection = Galluogi neu analluogi Rhwystro Cynnwys ac o ddewis ei gloi.
+
+# “lock” means that the user won’t be able to change this setting
+policy-EncryptedMediaExtensions = Galluogi neu analluogi Estyniadau Cyfryngau Amgryptiedig a'i gloi o ddewis.
+
+# A “locked” extension can’t be disabled or removed by the user. This policy
+# takes 3 keys (“Install”, ”Uninstall”, ”Locked”), you can either keep them in
+# English or translate them as verbs.
+policy-Extensions = Gosod, dadosod neu gloi estyniadau. Mae'r dewis gosod yn cymryd URL neu lwybrau fel paramedrau. Mae'r dewisiadau Dadosod a Chloi yn cymryd dynodiad estyniadau.
+
+policy-ExtensionSettings = Rheoli pob agwedd ar osod estyniad.
+
+policy-ExtensionUpdate = Galluogi neu analluogi diweddariadau awtomatig estyniad.
+
+policy-HardwareAcceleration = Os false, diffoddwch gyflymder y caledwedd.
+
+policy-InstallAddonsPermission = Caniatáu i wefannau penodol osod ychwanegion.
+
+policy-LegacyProfiles = Analluoga'r nodwedd gan orfodi proffil ar wahân ar gyfer pob gosodiad.
+
+## Do not translate "SameSite", it's the name of a cookie attribute.
+
+policy-LegacySameSiteCookieBehaviorEnabled = Galluogi gosodiad ymddygiad rhagosodedig y cwci SameSite blaenorol.
+
+policy-LegacySameSiteCookieBehaviorEnabledForDomainList = Dychwelyd i'r ymddygiad SameSite blaenorol ar gyfer cwcis ar wefannau penodol.
+
+##
+
+policy-LocalFileLinks = Caniatáu i wefannau penodol gysylltu â ffeiliau lleol.
+
+policy-NetworkPrediction = Galluogi neu analluogi rhagfynegiad rhwydwaith (DNS prefetching).
+
+policy-OfferToSaveLogins = Gorfodi'r gosodiad i ganiatáu i { -brand-short-name } gynnig cofio mewngofnodion a chyfrineiriau wedi eu cadw. Mae gwerthoedd gwir a gau'n cael eu derbyn.
+
+policy-OfferToSaveLoginsDefault = Gosod y gwerth rhagosodedig ar gyfer caniatáu i { -brand-short-name } gynnig cofio mewngofnodion a chyfrineiriau wedi'u cadw. Mae gwerthoedd gwir a ffug yn cael eu derbyn.
+
+policy-OverrideFirstRunPage = Diystyru y dudalen rhediad gyntaf. Gosod y polisi hwn i gwag os ydych am analluogi'r dudalen rhediad cyntaf.
+
+policy-OverridePostUpdatePage = Diystyru'r dudalen ôl ddiweddaru "Beth sy'n Newydd". Gosodwch y polisi hwn i gwag os hoffech chi analluogi'r dudalen ôl ddiweddaru.
+
+policy-PasswordManagerEnabled = Galluogi cadw cyfrineiriau i'r rheolwr cyfrinair.
+
+# PDF.js and PDF should not be translated
+policy-PDFjs = Analluogi neu ffurfweddu PDF.js, darllenydd PDF mewnol { -brand-short-name }.
+
+policy-Permissions2 = Ffurfweddu caniatâd ar gyfer camera, meicroffon, lleoliad, hysbysiadau ac awtochwarae.
+
+policy-Preferences = Gosod a chloi'r gwerth ar gyfer is-set o ddewisiadau.
+
+policy-PromptForDownloadLocation = Gofynnwch ble i arbed ffeiliau wrth eu llwytho i lawr.
+
+policy-Proxy = Ffurfweddi gosodiadau dirprwyol.
+
+policy-RequestedLocales = Gosod y rhestr o locales gofynnol ar gyfer y rhaglen yn ôl eich trefn dewis.
+
+policy-SanitizeOnShutdown2 = Clirio data llywio wrth gau.
+
+policy-SearchEngines = Ffurfweddu gosodiadau peiriannau chwilio. Dim ond yn y fersiwn Extended Support Release (ESR) mae'r polisi hwn ar gael.
+
+policy-SearchSuggestEnabled = Galluogi neu analluogi awgrymiadau chwilio.
+
+# For more information, see https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/PKCS11/Module_Installation
+policy-SecurityDevices = Gosod modiwlau PKCS#11.
+
+policy-SSLVersionMax = Gosod y fersiwn SSL uchaf.
+
+policy-SSLVersionMin = Gosodwch y fersiwn SSL leiaf.
+
+policy-SupportMenu = Ychwanegu eitem dewislen cymorth cyfaddas i'r ddewislen gymorth.
+
+policy-UserMessaging = Peidio dangos rhai negeseuon i'r defnyddiwr.
+
+# “format” refers to the format used for the value of this policy.
+policy-WebsiteFilter = Rhwystro gwefannau rhag derbyn ymweliadau. Gw. dogfennaeth am ragor o wybodaeth ar y fformat.
diff --git a/l10n-cy/mail/messenger/preferences/am-im.ftl b/l10n-cy/mail/messenger/preferences/am-im.ftl
new file mode 100644
index 0000000000..0f009ada36
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/am-im.ftl
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+account-settingsTitle = Gosodiadau Dilysu
+account-channelTitle = Sianeli Rhagosodedig
diff --git a/l10n-cy/mail/messenger/preferences/application-manager.ftl b/l10n-cy/mail/messenger/preferences/application-manager.ftl
new file mode 100644
index 0000000000..dcf0050f94
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/application-manager.ftl
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+app-manager-window-dialog =
+    .title = Manylion Rhaglen
+    .style = width: 30em; min-height: 20em;
+
+remove-app-button =
+    .label = Tynnu
+    .accesskey = T
diff --git a/l10n-cy/mail/messenger/preferences/attachment-reminder.ftl b/l10n-cy/mail/messenger/preferences/attachment-reminder.ftl
new file mode 100644
index 0000000000..ebb3e64efd
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/attachment-reminder.ftl
@@ -0,0 +1,26 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+attachment-reminder-window =
+    .title = Allweddair Atgoffa am Atodiad
+
+attachment-reminder-label = Bydd { -brand-short-name } yn eich rhybuddio am atodiadau coll os ydych ar fin anfon e-bost yn cynnwys un o'r allweddeiriau hyn.
+
+keyword-new-button =
+    .label = Newydd…
+    .accesskey = N
+
+keyword-edit-button =
+    .label = Golygu…
+    .accesskey = G
+
+keyword-remove-button =
+    .label = Dileu
+    .accesskey = D
+
+new-keyword-title = Allweddair Newydd
+new-keyword-label = Allweddair:
+
+edit-keyword-title = Golygu Allweddair
+edit-keyword-label = Allweddair:
diff --git a/l10n-cy/mail/messenger/preferences/colors.ftl b/l10n-cy/mail/messenger/preferences/colors.ftl
new file mode 100644
index 0000000000..1b3ed554ee
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/colors.ftl
@@ -0,0 +1,52 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+colors-dialog-window =
+    .title = Lliwiau
+    .style =
+        { PLATFORM() ->
+            [macos] width: 41em !important
+           *[other] width: 38em !important
+        }
+
+colors-dialog-legend = Testun a Chefndir
+
+text-color-label =
+    .value = Testun:
+    .accesskey = T
+
+background-color-label =
+    .value = Cefndir:
+    .accesskey = C
+
+use-system-colors =
+    .label = Defnyddio lliwiau'r system
+    .accesskey = s
+
+colors-link-legend = Lliw Dolenni
+
+link-color-label =
+    .value = Dolenni heb gael Ymweliad:
+    .accesskey = D
+
+visited-link-color-label =
+    .value = Dolenni wedi cael Ymweliad:
+    .accesskey = w
+
+underline-link-checkbox =
+    .label = Tanlinellu dolenni
+    .accesskey = d
+
+override-color-label =
+    .value = Anwybyddu'r lliwiau pennwyd gan y cynnwys gyda fy newis uchod:
+    .accesskey = A
+
+override-color-always =
+    .label = Bob tro
+
+override-color-auto =
+    .label = Dim ond gyda themâu Cyferbyniad Uchel
+
+override-color-never =
+    .label = Byth
diff --git a/l10n-cy/mail/messenger/preferences/connection.ftl b/l10n-cy/mail/messenger/preferences/connection.ftl
new file mode 100644
index 0000000000..e5576c8f0b
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/connection.ftl
@@ -0,0 +1,111 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+connection-dns-over-https-url-resolver = Defnyddio Darparwr
+    .accesskey = D
+
+# Variables:
+#   $name (String) - Display name or URL for the DNS over HTTPS provider
+connection-dns-over-https-url-item-default =
+    .label = { $name } (Rhagosodiad)
+    .tooltiptext = Defnyddiwch yr URL rhagosodedig ar gyfer datrys DNS dros HTTPS
+
+connection-dns-over-https-url-custom =
+    .label = Cyfaddas
+    .accesskey = C
+    .tooltiptext = Rhowch eich hoff URL er mwyn datrys DNS drod HTTPS
+
+connection-dns-over-https-custom-label = Cyfaddas
+
+connection-dialog-window =
+    .title = Gosodiadau Cysylltu
+    .style =
+        { PLATFORM() ->
+            [macos] width: 44em !important
+           *[other] width: 49em !important
+        }
+
+connection-proxy-legend = Ffurfweddu'r Dirprwyon i Gael Mynediad i'r Rhyngrwyd
+
+proxy-type-no =
+    .label = Dim dirprwy
+    .accesskey = D
+
+proxy-type-wpad =
+    .label = Awtoganfod gosodiadau dirprwyol ar gyfer y rhwydwaith
+    .accesskey = w
+
+proxy-type-system =
+    .label = Defnyddio gosodiadau dirprwyol y system
+    .accesskey = e
+
+proxy-type-manual =
+    .label = Ffurfweddiad dirprwy gyda llaw:
+    .accesskey = F
+
+proxy-http-label =
+    .value = Dirprwy yr HTTP:
+    .accesskey = H
+
+http-port-label =
+    .value = Porth:
+    .accesskey = P
+
+proxy-http-sharing =
+    .label = Defnyddiwch y dirprwy yma hefyd ar gyfer HTTPS
+    .accesskey = x
+
+proxy-https-label =
+    .value = Dirprwy HTTPS:
+    .accesskey = S
+
+ssl-port-label =
+    .value = Porth:
+    .accesskey = o
+
+proxy-socks-label =
+    .value = Gwesteiwr SOCKS:
+    .accesskey = C
+
+socks-port-label =
+    .value = Porth:
+    .accesskey = t
+
+proxy-socks4-label =
+    .label = SOCKS v4
+    .accesskey = K
+
+proxy-socks5-label =
+    .label = SOCKS v5
+    .accesskey = v
+
+proxy-type-auto =
+    .label = URL ffurfweddu dirprwy yn awtomatig:
+    .accesskey = U
+
+proxy-reload-label =
+    .label = Ail-lwytho
+    .accesskey = l
+
+no-proxy-label =
+    .value = Dim Dirprwy ar gyfer:
+    .accesskey = m
+
+no-proxy-example = Esiampl: .mozilla.org, .net.nz, 192.168.1.0/24
+
+# Note: Do not translate localhost, 127.0.0.1 and ::1.
+no-proxy-localhost-label = Nid yw cysylltiadau i localhost, 127.0.0.1, a ::1 byth yn cael eu dirprwyo.
+
+proxy-password-prompt =
+    .label = Peidio gofyn am ddilysiad os yw'r cyfrinair wedi ei gadw
+    .accesskey = d
+    .tooltiptext = Mae'r dewis hwn yn eich dilysu'n dawel i ddirprwyon rydych wedi eu cadw eu manylion ar eu cyfer. Byddwn yn gofyn os bydd y dilysiad yn methu.
+
+proxy-remote-dns =
+    .label = DNS dirprwyol pan y defnyddio SOCKS v5
+    .accesskey = D
+
+proxy-enable-doh =
+    .label = Galluogi DNS dros HTTPS
+    .accesskey = G
diff --git a/l10n-cy/mail/messenger/preferences/cookies.ftl b/l10n-cy/mail/messenger/preferences/cookies.ftl
new file mode 100644
index 0000000000..7e75018c83
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/cookies.ftl
@@ -0,0 +1,55 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+cookies-window-dialog =
+    .title = Cwcis
+    .style = width: 36em;
+
+window-close-key =
+    .key = w
+
+window-focus-search-key =
+    .key = f
+
+window-focus-search-alt-key =
+    .key = k
+
+filter-search-label =
+    .value = Chwilio:
+    .accesskey = h
+
+cookies-on-system-label = Mae'r cwcis canlynol wedi'u cadw ar eich cyfrifiadur:
+
+treecol-site-header =
+    .label = Gwefan
+
+treecol-name-header =
+    .label = Enw'r Cwci
+
+props-name-label =
+    .value = Enw:
+props-value-label =
+    .value = Cynnwys:
+props-domain-label =
+    .value = Gwesteiwr:
+props-path-label =
+    .value = Llwybr:
+props-secure-label =
+    .value = Anfon am:
+props-expires-label =
+    .value = Daw i ben:
+props-container-label =
+    .value = Cynhwysydd:
+
+remove-cookie-button =
+    .label = Tynnu Cwci
+    .accesskey = T
+
+remove-all-cookies-button =
+    .label = Tynnu Pob Cwci
+    .accesskey = P
+
+cookie-close-button =
+    .label = Cau
+    .accesskey = u
diff --git a/l10n-cy/mail/messenger/preferences/dock-options.ftl b/l10n-cy/mail/messenger/preferences/dock-options.ftl
new file mode 100644
index 0000000000..36a7f4012f
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/dock-options.ftl
@@ -0,0 +1,26 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+dock-options-window-dialog =
+    .title = Dewisiadau eicon yr ap
+    .style = width: 35em;
+
+bounce-system-dock-icon =
+    .label = Bywiogi eicon yr ap pan fydd neges newydd yn cyrraedd
+    .accesskey = B
+
+dock-icon-legend = Bathodyn eicon ap
+
+dock-icon-show-label =
+    .value = Bathodyn eicon ap gyda:
+
+count-unread-messages-radio =
+    .label = Cyfrif y negeseuon heb eu darllen
+    .accesskey = y
+
+count-new-messages-radio =
+    .label = Cyfrif y negeseuon newydd
+    .accesskey = y
+
+notification-settings-info = Gallwch analluogi'r bathodyn ym mhaen Hysbysiadau'r Dewisiadau System.
diff --git a/l10n-cy/mail/messenger/preferences/fonts.ftl b/l10n-cy/mail/messenger/preferences/fonts.ftl
new file mode 100644
index 0000000000..3acf212146
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/fonts.ftl
@@ -0,0 +1,151 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+fonts-window-close =
+    .key = w
+
+# Variables:
+#   $name {string, "Arial"} - Name of the default font
+fonts-label-default =
+    .label = Rhagosodiad ({ $name })
+fonts-label-default-unnamed =
+    .label = Rhagosodiad
+
+fonts-encoding-dialog-title =
+    .title = Ffontiau ac Amgodio
+
+fonts-language-legend =
+    .value = Ffontiau ar gyfer:
+    .accesskey = F
+
+fonts-proportional-label =
+    .value = Cyfrannol:
+    .accesskey = y
+
+## Languages
+
+# Note: Translate "Latin" as the name of Latin (Roman) script, not as the name of the Latin language.
+font-language-group-latin =
+    .label = Lladin
+font-language-group-japanese =
+    .label = Siapanëeg
+font-language-group-trad-chinese =
+    .label = Tsieinëeg Traddodiadol (Taiwan)
+font-language-group-simpl-chinese =
+    .label = Tsieinëeg Syml
+font-language-group-trad-chinese-hk =
+    .label = Tsieinëeg Traddodiadol (Hong Kong)
+font-language-group-korean =
+    .label = Corëeg
+font-language-group-cyrillic =
+    .label = Cyrilig
+font-language-group-el =
+    .label = Groeg
+font-language-group-other =
+    .label = Systemau Ysgrifennu Eraill
+font-language-group-thai =
+    .label = Thai
+font-language-group-hebrew =
+    .label = Hebraeg
+font-language-group-arabic =
+    .label = Arabeg
+font-language-group-devanagari =
+    .label = Devanagari
+font-language-group-tamil =
+    .label = Tamil
+font-language-group-armenian =
+    .label = Armeneg
+font-language-group-bengali =
+    .label = Bengali
+font-language-group-canadian =
+    .label = Sillafiad Unedig Canada
+font-language-group-ethiopic =
+    .label = Ethiopeg
+font-language-group-georgian =
+    .label = Georgeg
+font-language-group-gujarati =
+    .label = Gujarati
+font-language-group-gurmukhi =
+    .label = Gurmukhi
+font-language-group-khmer =
+    .label = Khmer
+font-language-group-malayalam =
+    .label = Malayalam
+font-language-group-math =
+    .label = Mathemateg
+font-language-group-odia =
+    .label = Odia
+font-language-group-telugu =
+    .label = Telugu
+font-language-group-kannada =
+    .label = Kannada
+font-language-group-sinhala =
+    .label = Sinhala
+font-language-group-tibetan =
+    .label = Tibeteg
+
+## Default font type
+
+default-font-serif =
+    .label = Serif
+
+default-font-sans-serif =
+    .label = Sans Serif
+
+font-size-label =
+    .value = Maint:
+    .accesskey = e
+
+font-size-monospace-label =
+    .value = Maint:
+    .accesskey = i
+
+font-serif-label =
+    .value = Serif:
+    .accesskey = S
+
+font-sans-serif-label =
+    .value = Sans-serif:
+    .accesskey = n
+
+font-monospace-label =
+    .value = Monospace:
+    .accesskey = M
+
+font-min-size-label =
+    .value = Lleiafswm maint ffont:
+    .accesskey = L
+
+min-size-none =
+    .label = Dim
+
+## Fonts in message
+
+font-control-legend = Rheoli Ffontiau
+
+use-document-fonts-checkbox =
+    .label = Caniatáu i negeseuon ddefnyddio ffontiau eraill
+    .accesskey = C
+
+use-fixed-width-plain-checkbox =
+    .label = Defnyddio ffont lled sefydlog ar gyfer negeseuon testun plaen
+    .accesskey = x
+
+## Language settings
+
+text-encoding-legend = Amgodiad Testun
+
+text-encoding-description = Gosod yr amgodiad testun rhagosodedig ar gyfer anfon a derbyn e-bost
+
+font-outgoing-email-label =
+    .value = Anfon E-bost:
+    .accesskey = A
+
+font-incoming-email-label =
+    .value = Derbyn E-bost:
+    .accesskey = D
+
+default-font-reply-checkbox =
+    .label = Pan yn bosib, defnyddio'r amgodiad testun rhagosodedig wrth ateb
+    .accesskey = a
diff --git a/l10n-cy/mail/messenger/preferences/languages.ftl b/l10n-cy/mail/messenger/preferences/languages.ftl
new file mode 100644
index 0000000000..ef00c61cb7
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/languages.ftl
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+languages-customize-moveup =
+    .label = Symud i Fyny
+    .accesskey = F
+
+languages-customize-movedown =
+    .label = Symud i Lawr
+    .accesskey = L
+
+languages-customize-remove =
+    .label = Tynnu
+    .accesskey = T
+
+languages-customize-select-language =
+    .placeholder = Dewis iaith i'w hychwanegu…
+
+languages-customize-add =
+    .label = Ychwanegu
+    .accesskey = Y
+
+messenger-languages-window =
+    .title = Gosodiadau Iaith { -brand-short-name }
+    .style = width: 40em
+
+messenger-languages-description = Bydd { -brand-short-name } yn dangos yr iaith gyntaf fel eich rhagosodedig a bydd yn danogs ieithoedd eraill yn y drefn fyddan nhw'n ymddangos.
+
+messenger-languages-search = Chwilio am ragor o ieithoedd…
+
+messenger-languages-searching =
+    .label = Chwilio am ieithoedd…
+
+messenger-languages-downloading =
+    .label = Llwytho i lawr…
+
+messenger-languages-select-language =
+    .label = Dewis iaith i'w hychwanegu…
+    .placeholder = Dewis iaith i'w hychwanegu…
+
+messenger-languages-installed-label = Ieithoedd wedi'u gosod
+messenger-languages-available-label = Ieithoedd ar gael
+
+messenger-languages-error = Nid yw { -brand-short-name } yn gallu diweddaru eich iaith ar hyn o bryd. Edrychwch i weld os ydych wedi'ch cysylltu i'r rhyngrwyd neu ceisiwch eto.
diff --git a/l10n-cy/mail/messenger/preferences/new-tag.ftl b/l10n-cy/mail/messenger/preferences/new-tag.ftl
new file mode 100644
index 0000000000..0791bf81a5
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/new-tag.ftl
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+tag-dialog-window =
+    .title = Tab Newydd
+
+tag-name-label =
+    .value = Enw Tag:
+    .accesskey = T
+
+tag-color-label =
+    .value = Lliw:
+    .accesskey = L
diff --git a/l10n-cy/mail/messenger/preferences/notifications.ftl b/l10n-cy/mail/messenger/preferences/notifications.ftl
new file mode 100644
index 0000000000..e2a52d3cda
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/notifications.ftl
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+notifications-dialog-window =
+    .title = Cyfaddasu Rhybudd E-bost Newydd
+
+customize-alert-description = Dewis pa faes i'w ddangos yn yr hysbysiad rhybudd:
+
+preview-text-checkbox =
+    .label = Testun Rhagolwg Neges
+    .accesskey = R
+
+subject-checkbox =
+    .label = Pwnc
+    .accesskey = P
+
+sender-checkbox =
+    .label = Anfonwr
+    .accesskey = A
+
+## Note: open-time-label-before is displayed first, then there's a field where
+## the user can enter a number, and open-time-label-after is displayed at the end
+## of the line. The translations of the open-time-label-before and open-time-label-after
+## parts don't have to mean the exact same thing as in English; please try instead
+## to translate the whole sentence.
+
+open-time-label-before =
+    .value = Dangos Rhybudd E-bost Newydd pob
+    .accesskey = N
+
+open-time-label-after =
+    .value = eiliad
diff --git a/l10n-cy/mail/messenger/preferences/offline.ftl b/l10n-cy/mail/messenger/preferences/offline.ftl
new file mode 100644
index 0000000000..af2da8cc8b
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/offline.ftl
@@ -0,0 +1,56 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+offline-dialog-window =
+    .title = Gosodiadau All-lein
+
+autodetect-online-label =
+    .label = Dilyn y cyflwr ar-lein canfuwyd, yn awtomatig
+    .accesskey = c
+
+startup-label = Cyflwr â llaw wrth gychwyn:
+
+status-radio-remember =
+    .label = Cofio'r cyflwr ar-lein diwethaf
+    .accesskey = o
+
+status-radio-ask =
+    .label = Gofyn i mi am y cyflwr ar-lein
+    .accesskey = G
+
+status-radio-always-online =
+    .label = Ar-lein
+    .accesskey = r
+
+status-radio-always-offline =
+    .label = All-lein
+    .accesskey = l
+
+going-online-label = Anfon negeseuon sydd heb eu hanfon wrth fynd ar-lein?
+
+going-online-auto =
+    .label = Iawn
+    .accesskey = I
+
+going-online-not =
+    .label = Na
+    .accesskey = N
+
+going-online-ask =
+    .label = Gofyn i mi
+    .accesskey = G
+
+going-offline-label = Llwytho negeseuon i lawr ar gyfer defnydd all-lein wrth fynd all-lein?
+
+going-offline-auto =
+    .label = Iawn
+    .accesskey = w
+
+going-offline-not =
+    .label = Na
+    .accesskey = a
+
+going-offline-ask =
+    .label = Gofyn i mi
+    .accesskey = f
diff --git a/l10n-cy/mail/messenger/preferences/passwordManager.ftl b/l10n-cy/mail/messenger/preferences/passwordManager.ftl
new file mode 100644
index 0000000000..b251d0a6b6
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/passwordManager.ftl
@@ -0,0 +1,85 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+saved-logins =
+    .title = Mewngofnodion wedi eu Cadw
+window-close =
+    .key = c
+focus-search-shortcut =
+    .key = f
+focus-search-altshortcut =
+    .key = k
+copy-provider-url-cmd =
+    .label = Copïo'r URL
+    .accesskey = U
+copy-username-cmd =
+    .label = Copïo Enw Defnyddiwr
+    .accesskey = E
+edit-username-cmd =
+    .label = Golygu Enw Defnyddiwr
+    .accesskey = G
+copy-password-cmd =
+    .label = Copïo'r Cyfrinair
+    .accesskey = o
+edit-password-cmd =
+    .label = Golygu'r Cyfrinair
+    .accesskey = G
+search-filter =
+    .accesskey = C
+    .placeholder = Chwilio
+column-heading-provider =
+    .label = Darparwr
+column-heading-username =
+    .label = Enw Defnyddiwr
+column-heading-password =
+    .label = Cyfrinair
+column-heading-time-created =
+    .label = Defnyddiwyd Gyntaf
+column-heading-time-last-used =
+    .label = Defnyddiwyd Diwethaf
+column-heading-time-password-changed =
+    .label = Newidiwyd Diwethaf
+column-heading-times-used =
+    .label = Nifer o Weithiau Defnyddiwyd
+remove =
+    .label = Tynnu
+    .accesskey = T
+import =
+    .label = Mewnforio…
+    .accesskey = M
+close-button =
+    .label = Cau
+    .accesskey = C
+
+show-passwords =
+    .label = Dangos Cyfrineiriau
+    .accesskey = D
+hide-passwords =
+    .label = Cuddio Cyfrineiriau
+    .accesskey = d
+logins-description-all = Mae mewngofnodion ar gyfer y darparwyr canlynol yn cael eu storio ar eich cyfrifiadur
+logins-description-filtered = Mae'r mewngofnodi canlynol yn cyd-fynd â'ch chwilio:
+remove-all =
+    .label = Tynnu Popeth
+    .accesskey = P
+remove-all-shown =
+    .label = Tynnu Popeth Dangoswyd
+    .accesskey = D
+remove-all-passwords-prompt = Ydych chi'n siŵr eich bod am dynnu pob cyfrinair?
+remove-all-passwords-title = Tynnu pob cyfrinair
+no-master-password-prompt = Ydych chi'n siŵr eich bod am ddangos eich cyfrineiriau?
+
+## OS Authentication dialog
+
+# This message can be seen by trying to show or copy the passwords.
+password-os-auth-dialog-message = Gwiriwch eich hunaniaeth i ddatgelu'r cyfrineiriau sydd wedi'u cadw.
+
+# This message can be seen by trying to show or copy the passwords.
+# The macOS strings are preceded by the operating system with "Thunderbird is trying to "
+# and includes subtitle of "Enter password for the user "xxx" to allow this." These
+# notes are only valid for English. Please test in your locale.
+password-os-auth-dialog-message-macosx = datgelu'r cyfrineiriau sydd wedi'u cadw
+
+# Don't change this label.
+password-os-auth-dialog-caption = { -brand-full-name }
diff --git a/l10n-cy/mail/messenger/preferences/permissions.ftl b/l10n-cy/mail/messenger/preferences/permissions.ftl
new file mode 100644
index 0000000000..b55e84c1ef
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/permissions.ftl
@@ -0,0 +1,56 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+permissions-reminder-window =
+    .title = Eithriadau
+    .style = width: 45em;
+
+window-close-key =
+    .key = w
+
+website-address-label =
+    .value = Cyfeiriad y wefan:
+    .accesskey = w
+
+block-button =
+    .label = Rhwystro
+    .accesskey = R
+
+allow-session-button =
+    .label = Caniatáu ar gyfer y Sesiwn
+    .accesskey = S
+
+allow-button =
+    .label = Caniatáu
+    .accesskey = a
+
+treehead-sitename-label =
+    .label = Gwefan
+
+treehead-status-label =
+    .label = Statws
+
+remove-site-button =
+    .label = Tynnu'r Wefan
+    .accesskey = T
+
+remove-all-site-button =
+    .label = Tynnu Pob Gwefan
+    .accesskey = P
+
+cancel-button =
+    .label = Diddymu
+    .accesskey = D
+
+save-button =
+    .label = Cadw Newidiadau
+    .accesskey = N
+
+permission-can-label = Caniatáu
+permission-can-access-first-party-label = Caniatáu'r parti cyntaf yn unig
+permission-can-session-label = Caniatáu ar gyfer y Sesiwn
+permission-cannot-label = Rhwystro
+
+invalid-uri-message = Rhowch gyfeiriad e-bost dilys
+invalid-uri-title = Rhoddwyd Enw Parth Annilys
diff --git a/l10n-cy/mail/messenger/preferences/preferences.ftl b/l10n-cy/mail/messenger/preferences/preferences.ftl
new file mode 100644
index 0000000000..8173225106
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/preferences.ftl
@@ -0,0 +1,715 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+close-button =
+    .aria-label = Cau
+preferences-title =
+    .title =
+        { PLATFORM() ->
+            [windows] Dewisiadau
+           *[other] Dewisiadau
+        }
+category-list =
+    .aria-label = Categorïau
+pane-general-title = Cyffredinol
+category-general =
+    .tooltiptext = { pane-general-title }
+pane-compose-title = Ysgrifennu
+category-compose =
+    .tooltiptext = Ysgrifennu
+pane-privacy-title = Preifatrwydd a Diogelwch
+category-privacy =
+    .tooltiptext = Preifatrwydd a Diogelwch
+pane-chat-title = Sgwrsio
+category-chat =
+    .tooltiptext = Sgwrsio
+pane-calendar-title = Calendr
+category-calendar =
+    .tooltiptext = Calendr
+general-language-and-appearance-header = Iaith a Gwedd
+general-incoming-mail-header = Derbyn E-byst
+general-files-and-attachment-header = Ffeiliau ac Atodiadau
+general-tags-header = Tagiau
+general-reading-and-display-header = Darllen a Dangos
+general-updates-header = Diweddariadau
+general-network-and-diskspace-header = Rhwydwaith a Lle ar Ddisg
+general-indexing-label = Mynegeio
+composition-category-header = Ysgrifennu
+composition-attachments-header = Atodiadau
+composition-spelling-title = Sillafu
+compose-html-style-title = Arddull HTML
+composition-addressing-header = Cyfeirio
+privacy-main-header = Preifatrwydd
+privacy-passwords-header = Cyfrineiriau
+privacy-junk-header = Sbam
+collection-header = Casglu a Defnyddio Data { -brand-short-name }
+collection-description = Rydym yn ceisio darparu dewisiadau i chi a chasglu dim ond beth sydd ei angen arnom i ddarparu a gwella { -brand-short-name } ar gyfer pawb. Rydym yn gofyn caniatâd bob tro cyn derbyn manylion personol.
+collection-privacy-notice = Hysbysiad Preifatrwydd
+collection-health-report-telemetry-disabled = Nid ydych bellach yn caniatáu i { -vendor-short-name } ddal data technegol a rhyngweithiol. Bydd holl ddata'r gorffennol yn cael ei ddileu cyn pen 30 diwrnod.
+collection-health-report-telemetry-disabled-link = Dysgu rhagor
+collection-health-report =
+    .label = Caniatáu i { -brand-short-name } anfon data technegol a rhyngweithio i { -vendor-short-name }
+    .accesskey = C
+collection-health-report-link = Dysgu rhagor
+# This message is displayed above disabled data sharing options in developer builds
+# or builds with no Telemetry support available.
+collection-health-report-disabled = Mae adrodd ar ddata wedi ei analluogi ar gyfer ffurfweddiad yr adeiledd hwn
+collection-backlogged-crash-reports =
+    .label = Caniatáu i { -brand-short-name } i anfon adroddiadau chwalu wedi eu cadw ar eich rhan
+    .accesskey = f
+collection-backlogged-crash-reports-link = Dysgu rhagor
+privacy-security-header = Diogelwch
+privacy-scam-detection-title = Canfod Twyll
+privacy-anti-virus-title = Gwrth Firws
+privacy-certificates-title = Tystysgrifau
+chat-pane-header = Sgwrsio
+chat-status-title = Statws
+chat-notifications-title = Hysbysiadau
+chat-pane-styling-header = Steilio
+choose-messenger-language-description = Dewis yr ieithoedd sy'n cael ei defnyddio i ddangos dewislenni, negeseuon, a hysbysiadau gan { -brand-short-name }
+manage-messenger-languages-button =
+    .label = Gosod Rhai Eraill...
+    .accesskey = G
+confirm-messenger-language-change-description = Ailgychwyn { -brand-short-name } i osod y newidiadau hyn
+confirm-messenger-language-change-button = Gosod ac Ailgychwyn
+update-setting-write-failure-title = Gwall wrth gadw dewisiadau Diweddaru
+# Variables:
+#   $path (String) - Path to the configuration file
+# The newlines between the main text and the line containing the path is
+# intentional so the path is easier to identify.
+update-setting-write-failure-message =
+    Bu gwall ar { -brand-short-name } ac nid yw wedi cadw'r newid hwn. Noder bod gosod caniatâd ar gyfer y diweddariad hwn yn gofyn am ganiatâd i ysgrifennu at y ffeil isod. Efallai y byddwch chi neu weinyddwr system yn gallu datrys y gwall trwy roi rheolaeth lawn i'r ffeil hon i'r grŵp Defnyddwyr.
+    
+    Doedd dim modd ysgrifennu i ffeil: { $path }
+update-in-progress-title = Diweddariad ar y Gweill
+update-in-progress-message = Ydych chi eisiau i { -brand-short-name } barhau gyda'r diweddariad hwn?
+update-in-progress-ok-button = &Dileu
+# Continue is the cancel button so pressing escape or using a platform standard
+# method of closing the UI will not discard the update.
+update-in-progress-cancel-button = &Parhau
+account-button = Gosodiadau'r Cyfrif
+addons-button = Estyniadau a Themâu
+
+## OS Authentication dialog
+
+# This message can be seen by trying to add a Master Password.
+master-password-os-auth-dialog-message-win = I greu Prif Gyfrinair, rhowch eich manylion mewngofnodi Windows. Mae hyn yn helpu i amddiffyn diogelwch eich cyfrifon.
+# This message can be seen by trying to add a Master Password.
+# The macOS strings are preceded by the operating system with "Thunderbird is trying to "
+# and includes subtitle of "Enter password for the user "xxx" to allow this." These
+# notes are only valid for English. Please test in your locale.
+master-password-os-auth-dialog-message-macosx = creu Prif Gyfrinair
+# This message can be seen by trying to add a Primary Password.
+primary-password-os-auth-dialog-message-win = I greu Prif Gyfrinair, nodwch fanylion eich mewngofnodi Windows. Mae hyn yn helpu i ddiogelu eich cyfrifon.
+# This message can be seen by trying to add a Primary Password.
+# The macOS strings are preceded by the operating system with "Thunderbird is trying to "
+# and includes subtitle of "Enter password for the user "xxx" to allow this." These
+# notes are only valid for English. Please test in your locale.
+primary-password-os-auth-dialog-message-macosx = creu Prif Gyfrinair
+# Don't change this label.
+master-password-os-auth-dialog-caption = { -brand-full-name }
+
+## General Tab
+
+focus-search-shortcut =
+    .key = f
+focus-search-shortcut-alt =
+    .key = k
+general-legend = Tudalen Cychwyn { -brand-short-name }
+start-page-label =
+    .label = Pan fydd { -brand-short-name } yn cychwyn, dangos y Dudalen Cychwyn yn y maes neges
+    .accesskey = P
+location-label =
+    .value = Lleoliad:
+    .accesskey = o
+restore-default-label =
+    .label = Adfer y Rhagosodiad
+    .accesskey = R
+default-search-engine = Peiriant Chwilio Rhagosodedig
+add-search-engine =
+    .label = Ychwanegu o ffeil
+    .accesskey = Y
+remove-search-engine =
+    .label = Tynnu
+    .accesskey = T
+minimize-to-tray-label =
+    .label = Pan fydd { -brand-short-name } wedi ei leihau, ei symud i'r dror
+    .accesskey = l
+new-message-arrival = Pan fydd neges newydd yn cyrraedd:
+mail-play-sound-label =
+    .label =
+        { PLATFORM() ->
+            [macos] Chwarae'r ffeil sain ganlynol:
+           *[other] Canu nodyn
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [macos] s
+           *[other] d
+        }
+mail-play-button =
+    .label = Chwarae
+    .accesskey = h
+change-dock-icon = Newid dewisiadau eicon yr ap
+app-icon-options =
+    .label = Dewisiadau Eicon Ap…
+    .accesskey = E
+notification-settings = Mae modd analluogi rhybuddion a'r sain rhagosodedig ar y paen Hysbysu y Dewisiadau System.
+animated-alert-label =
+    .label = Dangos rhybudd
+    .accesskey = D
+customize-alert-label =
+    .label = Cyfaddasu…
+    .accesskey = C
+tray-icon-label =
+    .label = Dangos eicon cilfach
+    .accesskey = c
+mail-system-sound-label =
+    .label = Sain rhagosodedig y system ar gyfer e-bost newydd
+    .accesskey = S
+mail-custom-sound-label =
+    .label = Defnyddio'r ffeil sain ganlynol
+    .accesskey = D
+mail-browse-sound-button =
+    .label = Pori…
+    .accesskey = P
+enable-gloda-search-label =
+    .label = Galluogi Chwilio a Mynegeio Eang
+    .accesskey = G
+datetime-formatting-legend = Fformatio Dyddiad ac Amser
+language-selector-legend = Iaith
+allow-hw-accel =
+    .label = Defnyddio cyflymu caledwedd pan fydd ar gael
+    .accesskey = y
+store-type-label =
+    .value = Math o Storio Negeseuon ar gyfer cyfrifon newydd:
+    .accesskey = M
+mbox-store-label =
+    .label = Ffeil i'r ffolder (mbox)
+maildir-store-label =
+    .label = Ffeil y neges (maildir)
+scrolling-legend = Sgrolio
+autoscroll-label =
+    .label = Defnyddio awto sgrolio
+    .accesskey = a
+smooth-scrolling-label =
+    .label = Defnyddio sgrolio llyfn
+    .accesskey = l
+system-integration-legend = Integreiddio System
+always-check-default =
+    .label = Gwirio bob tro os { -brand-short-name } yw'r rhaglen e-bost rhagosodedig wrth gychwyn
+    .accesskey = G
+check-default-button =
+    .label = Gwiriwch Nawr…
+    .accesskey = N
+# Note: This is the search engine name for all the different platforms.
+# Platforms that don't support it should be left blank.
+search-engine-name =
+    { PLATFORM() ->
+        [macos] Sbotolau
+        [windows] Chwilio Ffenestri
+       *[other] { "" }
+    }
+search-integration-label =
+    .label = Caniatáu i { search-engine-name } chwilio drwy'r negeseuon
+    .accesskey = C
+config-editor-button =
+    .label = Golygydd Ffurfweddu…
+    .accesskey = F
+return-receipts-description = Pennu sut mae { -brand-short-name } yn trin derbynebau
+return-receipts-button =
+    .label = Derbynebau Dychwelyd…
+    .accesskey = D
+update-app-legend = Diweddariadau { -brand-short-name }
+# Variables:
+#   $version (String): version of Thunderbird, e.g. 68.0.1
+update-app-version = Fersiwn { $version }
+allow-description = Gadael i { -brand-short-name } wneud
+automatic-updates-label =
+    .label = Gosod diweddariadau'n awtomatig (argymell: gwella diogelwch)
+    .accesskey = a
+check-updates-label =
+    .label = Gwirio am ddiweddariadau, ond gadael i mi ddewis i'w gosod a'i peidio
+    .accesskey = d
+update-history-button =
+    .label = Dangos Hanes Diweddaru
+    .accesskey = D
+use-service =
+    .label = Defnyddio gwasanaethau cefndirol i osod diweddariadau
+    .accesskey = e
+cross-user-udpate-warning = Bydd y gosodiad hwn yn berthnasol i holl gyfrifon Windows a phroffiliau { -brand-short-name } sy'n ddefnyddio'r gosodiad hwn { -brand-short-name }.
+networking-legend = Cysylltiad
+proxy-config-description = Ffurfweddu sut mae { -brand-short-name } yn cysylltu â'r Rhyngrwyd
+network-settings-button =
+    .label = Gosodiadau…
+    .accesskey = G
+offline-legend = All-lein
+offline-settings = Ffurfweddi gosodiadau all-lein
+offline-settings-button =
+    .label = All-lein…
+    .accesskey = l
+diskspace-legend = Lle ar Ddisg
+offline-compact-folder =
+    .label = Cywasgu pob ffolder pan fydd yn cadw dros gyfanswm o
+    .accesskey = y
+compact-folder-size =
+    .value = MB
+
+## Note: The entities use-cache-before and use-cache-after appear on a single
+## line in preferences as follows:
+## use-cache-before [ textbox for cache size in MB ] use-cache-after
+
+use-cache-before =
+    .value = Defnyddio hyd at
+    .accesskey = D
+use-cache-after = MB o le disg ar gyfer y storfa
+
+##
+
+smart-cache-label =
+    .label = Anwybyddu rheolaeth storfa awtomatig
+    .accesskey = A
+clear-cache-button =
+    .label = Clirio Nawr
+    .accesskey = N
+fonts-legend = Ffontiau a Lliwiau
+default-font-label =
+    .value = Ffont rhagosodedig:
+    .accesskey = r
+default-size-label =
+    .value = Maint:
+    .accesskey = M
+font-options-button =
+    .label = Uwch…
+    .accesskey = U
+color-options-button =
+    .label = Lliwiau…
+    .accesskey = L
+display-width-legend = Negeseuon Testun Plaen
+# Note : convert-emoticons-label 'Emoticons' are also known as 'Smileys', e.g. :-)
+convert-emoticons-label =
+    .label = Dangos gwenogluniau fel graffigau
+    .accesskey = g
+display-text-label = Wrth ddangos negeseuon testun plaen dyfynedig:
+style-label =
+    .value = Arddull:
+    .accesskey = A
+regular-style-item =
+    .label = Arferol
+bold-style-item =
+    .label = Trwm
+italic-style-item =
+    .label = Italig
+bold-italic-style-item =
+    .label = Italig Trwm
+size-label =
+    .value = Maint:
+    .accesskey = M
+regular-size-item =
+    .label = Arferol
+bigger-size-item =
+    .label = Mwy
+smaller-size-item =
+    .label = Llai
+quoted-text-color =
+    .label = Lliw:
+    .accesskey = L
+search-input =
+    .placeholder = Chwilio
+type-column-label =
+    .label = Math o Gynnwys
+    .accesskey = M
+action-column-label =
+    .label = Gweithred
+    .accesskey = G
+save-to-label =
+    .label = Cadw ffeiliau yn
+    .accesskey = C
+choose-folder-label =
+    .label =
+        { PLATFORM() ->
+            [macos] Dewis…
+           *[other] Pori…
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [macos] D
+           *[other] P
+        }
+always-ask-label =
+    .label = Gofyn i mi lle i gadw pob ffeil
+    .accesskey = G
+display-tags-text = Mae modd defnyddio tagiau i gategoreiddio a blaenoriaethu eich negeseuon.
+new-tag-button =
+    .label = Newydd…
+    .accesskey = N
+edit-tag-button =
+    .label = Golygu…
+    .accesskey = G
+delete-tag-button =
+    .label = Dileu
+    .accesskey = D
+auto-mark-as-read =
+    .label = Marcio'n awtomatig negeseuon wedi'u darllen
+    .accesskey = a
+mark-read-no-delay =
+    .label = Dangos yn syth
+    .accesskey = s
+
+## Note: This will concatenate to "After displaying for [___] seconds",
+## using (mark-read-delay) and a number (seconds-label).
+
+mark-read-delay =
+    .label = Ar ôl dangos am
+    .accesskey = d
+seconds-label = eiliad
+
+##
+
+open-msg-label =
+    .value = Agor neges mewn:
+open-msg-tab =
+    .label = Tab newydd
+    .accesskey = T
+open-msg-window =
+    .label = Ffenestr neges newydd
+    .accesskey = n
+open-msg-ex-window =
+    .label = Ffenestr neges gyfredol
+    .accesskey = g
+close-move-delete =
+    .label = Cau ffenestr/tab neges wrth symud neu ddileu
+    .accesskey = C
+display-name-label =
+    .value = Enw dangos:
+condensed-addresses-label =
+    .label = Dangos dim ond enw dangos unigolion yn fy llyfr cyfeiriadau
+    .accesskey = D
+
+## Compose Tab
+
+forward-label =
+    .value = Anfon negeseuon ymlaen:
+    .accesskey = y
+inline-label =
+    .label = Mewnlin
+as-attachment-label =
+    .label = Fel Atodiad
+extension-label =
+    .label = ychwanegu estyniad i enw ffeil
+    .accesskey = e
+
+## Note: This will concatenate to "Auto Save every [___] minutes",
+## using (auto-save-label) and a number (auto-save-end).
+
+auto-save-label =
+    .label = Awto Gadw pob
+    .accesskey = G
+auto-save-end = munud
+
+##
+
+warn-on-send-accel-key =
+    .label = Cadarnhau wrth ddefnyddio llwybr byr bysellfwrdd i anfon neges
+    .accesskey = b
+spellcheck-label =
+    .label = Gwirio sillafu cyn anfon
+    .accesskey = s
+spellcheck-inline-label =
+    .label = Galluogi gwirio sillafu wrth deipio
+    .accesskey = E
+language-popup-label =
+    .value = Iaith:
+    .accesskey = I
+download-dictionaries-link = Llwytho i Lawr Rhagor o Eiriaduron
+font-label =
+    .value = Ffont:
+    .accesskey = F
+font-size-label =
+    .value = Maint:
+    .accesskey = M
+default-colors-label =
+    .label = Defnyddio lliwiau rhagosodedig y darllenydd
+    .accesskey = d
+font-color-label =
+    .value = Lliw Testun:
+    .accesskey = L
+bg-color-label =
+    .value = Lliw Cefndir:
+    .accesskey = C
+restore-html-label =
+    .label = Adfer y Rhagosodiad
+    .accesskey = R
+default-format-label =
+    .label = Defnyddio'r Fformat Paragraff yn lle Testun Corff drwy ragosodiad
+    .accesskey = P
+format-description = Ffurfweddi ymddygiad fformat testun
+send-options-label =
+    .label = Dewisiadau Anfon…
+    .accesskey = A
+autocomplete-description = Wrth gyfeirio negeseuon, chwilio am gofnodion cyfatebol yn:
+ab-label =
+    .label = Llyfrau Cyfeiriadau Lleol
+    .accesskey = L
+directories-label =
+    .label = Gweinydd Cyfeiriadur:
+    .accesskey = G
+directories-none-label =
+    .none = Dim
+edit-directories-label =
+    .label = Golygu Cyfeiriaduron…
+    .accesskey = C
+email-picker-label =
+    .label = Ychwanegu cyfeiriadau e-bost anfon yn awtomatig i'r:
+    .accesskey = Y
+default-directory-label =
+    .value = Cyfeiriadur cychwyn rhagosodedig yn ffenestr y llyfr cyfeiriadau:
+    .accesskey = c
+default-last-label =
+    .none = Cyfeiriadur defnyddiwyd ddiwethaf
+attachment-label =
+    .label = Gwirio am atodiadau coll
+    .accesskey = w
+attachment-options-label =
+    .label = Allweddeiriau…
+    .accesskey = w
+enable-cloud-share =
+    .label = Cynnig rhannu ffeiliau sy'n fwy na
+cloud-share-size =
+    .value = MB
+add-cloud-account =
+    .label = Ychwanegu…
+    .accesskey = Y
+    .defaultlabel = Ychwanegu…
+remove-cloud-account =
+    .label = Tynnu
+    .accesskey = T
+find-cloud-providers =
+    .value = Canfod rhagor o ddarparwyr…
+cloud-account-description = Ychwanegu gwasanaeth storio Filelink newydd
+
+## Privacy Tab
+
+mail-content = Cynnwys E-bost
+remote-content-label =
+    .label = Caniatáu cynnwys pell o fewn negeseuon
+    .accesskey = C
+exceptions-button =
+    .label = Eithriadau…
+    .accesskey = E
+remote-content-info =
+    .value = Dysgu rhagor am faterion preifatrwydd cynnwys pell
+web-content = Cynnwys Gwe
+history-label =
+    .label = Cofio gwefannau a dolenni rwyf wedi ymweld â nhw
+    .accesskey = o
+cookies-label =
+    .label = Derbyn cwcis gan wefannau
+    .accesskey = D
+third-party-label =
+    .value = Derbyn cwcis trydydd parti:
+    .accesskey = D
+third-party-always =
+    .label = Bob tro
+third-party-never =
+    .label = Byth
+third-party-visited =
+    .label = O'r ymwelwyd
+keep-label =
+    .value = Cadw tan:
+    .accesskey = C
+keep-expire =
+    .label = daw i ben
+keep-close =
+    .label = Cau { -brand-short-name }
+keep-ask =
+    .label = gofyn i mi bob tro
+cookies-button =
+    .label = Dangos Cwcis…
+    .accesskey = D
+do-not-track-label =
+    .label = Anfon neges “Dim Tracio” at wefannau nad ydych am gael eich tracio
+    .accesskey = D
+learn-button =
+    .label = Dysgu rhagor
+passwords-description = Mae { -brand-short-name } yn gallu cofio cyfrineiriau eich holl cyfrifon.
+passwords-button =
+    .label = Cyfrineiriau sydd wedi'u cadw…
+    .accesskey = C
+master-password-description = Mae Prif Gyfrinair yn diogelu eich holl gyfrineiriau, ond mae'n rhaid i chi ei roi unwaith bob sesiwn.
+master-password-label =
+    .label = Defnyddio prif gyfrinair
+    .accesskey = p
+master-password-button =
+    .label = Newid y Prif Gyfrinair…
+    .accesskey = N
+primary-password-description = Mae Prif Gyfrinair yn diogelu eich holl gyfrineiriau, ond rhaid i chi ei osod unwaith y sesiwn.
+primary-password-label =
+    .label = Defnyddio Prif Gyfrinair
+    .accesskey = D
+primary-password-button =
+    .label = Newid y Prif Gyfrinair…
+    .accesskey = N
+forms-primary-pw-fips-title = Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+forms-master-pw-fips-desc = Methodd Newid eich Cyfrinair
+junk-description = Yma gallwch osod eich gosodiadau sbam rhagosodedig. Mae modd ffurfweddu gosodiadau penodol ar gyfer sbam yn Gosodiadau Cyfrif.
+junk-label =
+    .label = Pan fyddai'n marcio negeseuon fel sbam:
+    .accesskey = P
+junk-move-label =
+    .label = Eu symud i ffolder "Sbam" y cyfrif
+    .accesskey = b
+junk-delete-label =
+    .label = Eu dileu
+    .accesskey = d
+junk-read-label =
+    .label = Marcio negeseuon Sbam fel rhai wedi'u darllen
+    .accesskey = a
+junk-log-label =
+    .label = Galluogi cofnodi hidlo sbam addasol
+    .accesskey = G
+junk-log-button =
+    .label = Dangos y cofnod
+    .accesskey = c
+reset-junk-button =
+    .label = Ailosod Data Hyfforddi
+    .accesskey = A
+phishing-description = Mae { -brand-short-name } yn gallu dadansoddi negeseuon am dwyll e-bost drwy edrych am dechnegau cyffredin i'ch twyllo.
+phishing-label =
+    .label = Dweud wrthyf os yw'r neges ryw'n ei darllen o bosib yn e-bost twyllodrus
+    .accesskey = D
+antivirus-description = Mae { -brand-short-name } yn gallu ei gwneud yn hawdd i feddalwedd gwrth firws ddadansoddi negeseuon e-byst sy'n cael eu derbyn am firysau cyn eu storio'n lleol.
+antivirus-label =
+    .label = Caniatáu i'r rhaglen neilltuo negeseuon sy'n cael eu derbyn
+    .accesskey = a
+certificate-description = Pan fydd gweinydd yn gofyn am fy nhystysgrif bersonol:
+certificate-auto =
+    .label = Dewis un yn awtomatig
+    .accesskey = D
+certificate-ask =
+    .label = Gofyn i mi bob tro
+    .accesskey = G
+ocsp-label =
+    .label = Ymholi gweinyddion ymatebydd OCSP i gadarnhau dilysrwydd cyfredol y tystysgrifau
+    .accesskey = Y
+certificate-button =
+    .label = Rheoli Tystysgrifau…
+    .accesskey = R
+security-devices-button =
+    .label = Dyfeisiau Diogelwch…
+    .accesskey = D
+
+## Chat Tab
+
+startup-label =
+    .value = Pan fydd { -brand-short-name } yn cychwyn:
+    .accesskey = P
+offline-label =
+    .label = Cadw fy Nghyfrifon Sgwrsio all-lein
+auto-connect-label =
+    .label = Cysylltu â fy nghyfrifon sgwrsio yn awtomatig
+
+## Note: idle-label is displayed first, then there's a field where the user
+## can enter a number, and itemTime is displayed at the end of the line.
+## The translations of the idle-label and idle-time-label parts don't have
+## to mean the exact same thing as in English; please try instead to
+## translate the whole sentence.
+
+idle-label =
+    .label = Hysbysu fy nghysylltiadau fy mod yn Segur ar ôl
+    .accesskey = S
+idle-time-label = munud o seibiant
+
+##
+
+away-message-label =
+    .label = a dynodi fy statws i I Ffwrdd gyda'r neges statws yma:
+    .accesskey = F
+send-typing-label =
+    .label = Anfon hysbysiadau teipio mewn trafodaethau
+    .accesskey = h
+notification-label = Pan fydd negeseuon wedi eu cyfeirio atoch chi yn cyrraedd:
+show-notification-label =
+    .label = Dangos rhybudd:
+    .accesskey = r
+notification-all =
+    .label = gydag enw'r anfonwr a rhagolwg o'r neges
+notification-name =
+    .label = gydag enw'r anfonwr yn unig
+notification-empty =
+    .label = heb unrhyw wybodaeth
+notification-type-label =
+    .label =
+        { PLATFORM() ->
+            [macos] Animeiddio eitem docio
+           *[other] Fflachio'r eitem bar tasgau
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [macos] o
+           *[other] F
+        }
+chat-play-sound-label =
+    .label = Canu nodyn
+    .accesskey = C
+chat-play-button =
+    .label = Chwarae
+    .accesskey = h
+chat-system-sound-label =
+    .label = Sain rhagosodedig y system ar gyfer e-bost newydd
+    .accesskey = S
+chat-custom-sound-label =
+    .label = Defnyddio'r ffeil sain ganlynol
+    .accesskey = D
+chat-browse-sound-button =
+    .label = Pori…
+    .accesskey = P
+theme-label =
+    .value = Thema:
+    .accesskey = T
+style-thunderbird =
+    .label = Thunderbird
+style-bubbles =
+    .label = Swigod
+style-dark =
+    .label = Tywyll
+style-paper =
+    .label = Dalennau Papur
+style-simple =
+    .label = Syml
+preview-label = Rhagolwg:
+no-preview-label = Dim rhagolwg ar gael
+no-preview-description = Nid yw'r thema yma'n ddilys nac ar gael ar hyn o bryd (ychwanegyn wedi ei analluogi, modd diogel, …).
+chat-variant-label =
+    .value = Amrywiad:
+    .accesskey = A
+chat-header-label =
+    .label = Dangos Pennyn
+    .accesskey = P
+# This is used to determine the width of the search field in about:preferences,
+# in order to make the entire placeholder string visible
+#
+# Please keep the placeholder string short to avoid truncation.
+#
+# Notice: The value of the `.style` attribute is a CSS string, and the `width`
+# is the name of the CSS property. It is intended only to adjust the element's width.
+# Do not translate.
+search-input-box =
+    .style = width: 15.4em
+    .placeholder =
+        { PLATFORM() ->
+            [windows] Canfod yn Dewisiadau
+           *[other] Canfod yn Dewisiadau
+        }
+
+## Preferences UI Search Results
+
+search-results-header = Canlyniadau Chwilio
+# `<span data-l10n-name="query"></span>` will be replaced by the search term.
+search-results-empty-message =
+    { PLATFORM() ->
+        [windows] Ymddiheuriadau! Nid os canlyniadau yn y Dewisiadau ar gyfer “<span data-l10n-name="query"></span>”.
+       *[other] Ymddiheuriadau! Nid os canlyniadau yn y Dewisiadau ar gyfer “<span data-l10n-name="query"></span>”.
+    }
+search-results-help-link = Angen cymorth? Ewch i <a data-l10n-name="url">Cefnogaeth { -brand-short-name }</a>
diff --git a/l10n-cy/mail/messenger/preferences/receipts.ftl b/l10n-cy/mail/messenger/preferences/receipts.ftl
new file mode 100644
index 0000000000..57bdadd568
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/receipts.ftl
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+receipts-dialog-window =
+    .title = Derbynebau Dychwelyd
+
+return-receipt-checkbox =
+    .label = Wrth anfon negeseuon, gofyn bob tro am dderbynneb dychwelyd
+    .acceskey = W
+
+receipt-arrive-label = Pan fydd derbynneb yn cyrraedd:
+
+receipt-leave-radio =
+    .label = Ei gadael yn fy Mlwch Derbyn
+    .acceskey = E
+
+receipt-move-radio =
+    .label = Symud i fy ffolder "Anfon"
+    .acceskey = f
+
+receipt-request-label = Pan fyddaf yn derbyn cais am dderbynneb dychwelyd:
+
+receipt-return-never-radio =
+    .label = Peidio anfon derbynneb dychwelyd
+    .acceskey = P
+
+receipt-return-some-radio =
+    .label = Caniatáu derbynebau dychwelyd ar gyfer rhai negeseuon
+    .acceskey = a
+
+receipt-not-to-cc =
+    .value = Os nad wyf yn At neu Cc y neges:
+    .acceskey = O
+
+receipt-send-never-label =
+    .label = Byth anfon
+
+receipt-send-always-label =
+    .label = Anfon pob tro
+
+receipt-send-ask-label =
+    .label = Gofyn i mi
+
+sender-outside-domain =
+    .value = Os yw'r anfonwr o'r tu allan i'm parth:
+    .acceskey = s
+
+other-cases-label =
+    .value = Mewn unrhyw achos arall:
+    .acceskey = M
diff --git a/l10n-cy/mail/messenger/preferences/sendoptions.ftl b/l10n-cy/mail/messenger/preferences/sendoptions.ftl
new file mode 100644
index 0000000000..1574d32a0d
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/sendoptions.ftl
@@ -0,0 +1,50 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+sendoptions-dialog-window =
+    .title = Dewisiadau Anfon
+
+send-mail-title = Fformat Testun
+
+auto-downgrade-label =
+    .label = Anfon negeuon fel testun plaen os yn bosib
+    .accesskey = t
+
+default-html-format-label = Wrth anfon negeseuon mewn fformat HTML ac nad yw un neu fwy o'r derbynwyr wedi'u rhestru fel eu bod yn gallu derbyn HTML:
+
+html-format-ask =
+    .label = Gofyn i mi beth i'w wneud
+    .accesskey = G
+
+html-format-convert =
+    .label = Trosi'r neges i destun plaen
+    .accesskey = T
+
+html-format-send-html =
+    .label = Anfon y neges mewn HTML beth bynnag
+    .accesskey = n
+
+html-format-send-both =
+    .label = Anfon y neges mewn testun plaen a HTML
+    .accesskey = A
+
+default-html-format-info = Sylw: Defnyddiwch y Llyfr Cyfeiriadau i bennu fformat testun dewisol ar gyfer derbyniwr.
+
+html-tab-label =
+    .label = Parthau HTML
+    .accesskey = H
+
+plain-tab-label =
+    .label = Parthau Testun Plaen
+    .accesskey = P
+
+send-message-domain-label = Pan fyddwch yn anfon neges i gyfeiriad gydag un o'r enwau parth sydd wedi rhestri isod, bydd { -brand-short-name } yn anfon y neges yn ei fformat cywir yn awtomatig.
+
+add-domain-button =
+    .label = Ychwanegu…
+    .accesskey = Y
+
+delete-domain-button =
+    .label = Dileu
+    .accesskey = D
diff --git a/l10n-cy/mail/messenger/preferences/system-integration.ftl b/l10n-cy/mail/messenger/preferences/system-integration.ftl
new file mode 100644
index 0000000000..b3e182efa9
--- /dev/null
+++ b/l10n-cy/mail/messenger/preferences/system-integration.ftl
@@ -0,0 +1,38 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+system-integration-title =
+    .title = Integreiddio System
+system-integration-dialog =
+    .buttonlabelaccept = Gosod fel Rhagosodiad
+    .buttonlabelcancel = Hepgor Integreiddio
+    .buttonlabelcancel2 = Diddymu
+default-client-intro = Defnyddio { -brand-short-name } fel y rhaglen rhagosodedig ar gyfer:
+unset-default-tooltip = Nid yw'n bosib dadosod { -brand-short-name } fel y cleient rhagosodedig o fewn { -brand-short-name }. I wneud rhaglen arall y rhagosodedig rhaid defnyddio ei ddeialog 'Gosod fel y rhagosodedig' ei hun.
+checkbox-email-label =
+    .label = E-Bost
+    .tooltiptext = { unset-default-tooltip }
+checkbox-newsgroups-label =
+    .label = Grwpiau Newyddion
+    .tooltiptext = { unset-default-tooltip }
+checkbox-feeds-label =
+    .label = Llif
+    .tooltiptext = { unset-default-tooltip }
+checkbox-calendar-label =
+    .label = Calendr
+    .tooltiptext = { unset-default-tooltip }
+# Note: This is the search engine name for all the different platforms.
+# Platforms that don't support it should be left blank.
+system-search-engine-name =
+    { PLATFORM() ->
+        [macos] Sbotolau
+        [windows] Chwilio Ffenestri
+       *[other] { "" }
+    }
+system-search-integration-label =
+    .label = Caniatáu i { system-search-engine-name } chwilio drwy'r negeseuon
+    .accesskey = C
+check-on-startup-label =
+    .label = Gwirio hwn bob tro wrth gychwyn { -brand-short-name }
+    .accesskey = G
diff --git a/l10n-cy/mail/updater/updater.ini b/l10n-cy/mail/updater/updater.ini
new file mode 100644
index 0000000000..d31b5fc786
--- /dev/null
+++ b/l10n-cy/mail/updater/updater.ini
@@ -0,0 +1,7 @@
+; This Source Code Form is subject to the terms of the Mozilla Public
+; License, v. 2.0. If a copy of the MPL was not distributed with this
+; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+; This file is in the UTF-8 encoding
+[Strings]
+TitleText=Diweddaru %MOZ_APP_DISPLAYNAME%
+InfoText=Mae %MOZ_APP_DISPLAYNAME% yn gosod eich diweddariadau a bydd yn cychwyn ymhen ychydig…
diff --git a/l10n-cy/mobile/android/chrome/about.dtd b/l10n-cy/mobile/android/chrome/about.dtd
new file mode 100644
index 0000000000..5724408cd7
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/about.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!ENTITY aboutPage.title                        "Ynghylch &brandShortName;">
+<!ENTITY aboutPage.warningVersion               "Mae &brandShortName; yn arbrofol a gall fod yn ansad.">
+<!ENTITY aboutPage.checkForUpdates.link         "Gwirio am Ddiweddariad »">
+<!ENTITY aboutPage.checkForUpdates.checking     "Chwilio am ddiweddariadau…">
+<!ENTITY aboutPage.checkForUpdates.none         "Dim diweddariadau ar gael">
+<!ENTITY aboutPage.checkForUpdates.available2   "Llwytho'r diweddariad i lawr">
+<!ENTITY aboutPage.checkForUpdates.downloading  "Llwytho'r diweddariad i lawr…">
+<!ENTITY aboutPage.checkForUpdates.downloaded2  "Gosod diweddariad">
+<!ENTITY aboutPage.faq.label                    "Atebion">
+<!ENTITY aboutPage.support.label                "Cefnogaeth">
+<!ENTITY aboutPage.privacyPolicy.label          "Polisi Preifatrwydd">
+<!ENTITY aboutPage.rights.label                 "Gwybod eich Hawliau">
+<!ENTITY aboutPage.relNotes.label               "Nodiadau Rhyddhau">
+<!ENTITY aboutPage.credits.label                "Diolchiadau">
+<!ENTITY aboutPage.license.label                "Manylion Trwyddedu">
+<!-- LOCALIZATION NOTE (aboutPage.logoTrademark): The message is explicitly about the word "Firefox" being trademarked, that's why we use it, instead of brandShortName. -->
+
+<!ENTITY aboutPage.logoTrademark                "Mae Firefox a'r logos Firefox yn nodau masnach y Mozilla Foundation.">
diff --git a/l10n-cy/mobile/android/chrome/aboutAccounts.dtd b/l10n-cy/mobile/android/chrome/aboutAccounts.dtd
new file mode 100644
index 0000000000..f319e96944
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutAccounts.dtd
@@ -0,0 +1,13 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY aboutAccounts.connected.title "Cyfrifon Firefox">
+<!ENTITY aboutAccounts.connected.description "Rydych wedi cysylltu fel">
+<!ENTITY aboutAccounts.syncPreferences.label "Tapio yma i wirio eich gosodiadau Sync">
+
+<!ENTITY aboutAccounts.noConnection.title "Dim cysylltiad gwe">
+<!ENTITY aboutAccounts.retry.label "Ceisio eto">
+
+<!ENTITY aboutAccounts.restrictedError.title "Cyfyngedig">
+<!ENTITY aboutAccounts.restrictedError.description "Nid oes modd i chi reoli Cyfrifon Firefox o'r proffil hwn.">
diff --git a/l10n-cy/mobile/android/chrome/aboutAccounts.properties b/l10n-cy/mobile/android/chrome/aboutAccounts.properties
new file mode 100644
index 0000000000..a284e7aefb
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutAccounts.properties
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (relinkDenied.message): Ideally, this string is short (it's
+# a toast message).
+relinkDenied.message = Eisoes wedi mewngofnodi i Sync!
+# LOCALIZATION NOTE (relinkDenied.openPrefs): Ideally, this string is short (it's a
+# button label) and upper-case, to match Google and Android's convention.
+relinkDenied.openPrefs = DEWIS
+
+relinkVerify.title = Ydych chi'n siŵr eich bod eisiau mewngofnodi i Sync?
+# LOCALIZATION NOTE (relinkVerify.message): Email address of a user previously signed in to Sync.
+relinkVerify.message = Roeddech wedi mewngofnodi i Sync gyda chyfeiriad e-bost gwahanol. Bydd mewngofnodi yn cyfuno nodau tudalen, cyfrineiriau a gosodiadau eraill y porwr hwn gyda %S
+relinkVerify.continue = Parhau
+relinkVerify.cancel = Diddymu
diff --git a/l10n-cy/mobile/android/chrome/aboutAddons.dtd b/l10n-cy/mobile/android/chrome/aboutAddons.dtd
new file mode 100644
index 0000000000..05fc62e24b
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutAddons.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY aboutAddons.title2                     "Ychwanegion">
+<!ENTITY aboutAddons.header2                    "Eich Ychwanegion">
+
+<!ENTITY addonAction.enable                     "Galluogi">
+<!ENTITY addonAction.disable                    "Atal">
+<!ENTITY addonAction.uninstall                  "Dadosod">
+<!ENTITY addonAction.undo                       "Dadwneud">
+<!ENTITY addonAction.update                     "Diweddaru">
+
+<!ENTITY addonUnsigned.message                  "Nid oedd modd i &brandShortName; ddilysu'r ychwanegyn hwn.">
+<!ENTITY addonUnsigned.learnMore                "Dysgu rhagor">
diff --git a/l10n-cy/mobile/android/chrome/aboutAddons.properties b/l10n-cy/mobile/android/chrome/aboutAddons.properties
new file mode 100644
index 0000000000..e4d7d1d0ba
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutAddons.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addonStatus.uninstalled=Bydd %S yn cael ei ddadosod ar ôl i chi ail gychwyn.
+
+# Will keep both strings and at runtime will fallback on the old one if the new one is not yet localized
+addons.browseAll=Porwch Ychwanegion Firefox
+
+addons.browseRecommended=Porwch Estyniadau Cymeradwy Firefox
+
+addon.options=Dewisiadau
diff --git a/l10n-cy/mobile/android/chrome/aboutCertError.dtd b/l10n-cy/mobile/android/chrome/aboutCertError.dtd
new file mode 100644
index 0000000000..5d8b5fce9c
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutCertError.dtd
@@ -0,0 +1,31 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
+  %brandDTD;
+
+<!-- These strings are used by Firefox's custom about:certerror page,
+a replacement for the standard security certificate errors produced
+by NSS/PSM via netError.xhtml. -->
+
+
+<!ENTITY certerror.pagetitle  "Dim Ymddiriedaeth i'r Cysylltiad">
+<!ENTITY certerror.longpagetitle "Dim Ymddiriedaeth i'r Cysylltiad">
+<!-- Localization note (certerror.introPara1) - The string "#1" will
+be replaced at runtime with the name of the server to which the user
+was trying to connect. -->
+
+<!ENTITY certerror.introPara1 "Rydych wedi gofyn i &brandShortName; gysylltu yn ddiogel i <b>#1</b>, ond nid ydym yn gallu cadarnhau fod y cysylltiad yn un diogel.">
+
+<!ENTITY certerror.whatShouldIDo.heading "Beth Ddylwn i Wneud?">
+<!ENTITY certerror.whatShouldIDo.content "Os ydych yn cysylltu â'r wefan hon heb anhawster fel rheol, gall y gwall olygu fod rhywun yn ceisio dynwared y wefan, peidiwch mynd ymhellach.">
+<!ENTITY certerror.getMeOutOfHere.label "Allan o fan hyn!">
+
+<!ENTITY certerror.expert.heading "Rwy'n Deall y Peryglon">
+<!ENTITY certerror.expert.content "Os ydych yn deall beth sydd ar waith, mae modd dweud wrth &brandShortName; i ymddiried yn dynodiad y wefan. <b>Hyd yn oed os ydych yn ymddiried yn y wefan, mae'r gwall yn gallu golygu fod rhywun wedi ymyrryd â'ch cysylltiad.</b>">
+<!ENTITY certerror.expert.contentPara2 "Peidiwch ychwanegu eithriad heblaw eich bod yn gwybod fod rheswm da pam nad yw'r wefan yn defnyddio dynodiadau mae modd ymddiried ynddynt.">
+<!ENTITY certerror.addTemporaryException.label "Ymweld â'r wefan">
+<!ENTITY certerror.addPermanentException.label "Ychwanegu eithriad parhaol">
+
+<!ENTITY certerror.technical.heading "Manylion Technegol">
diff --git a/l10n-cy/mobile/android/chrome/aboutDownloads.dtd b/l10n-cy/mobile/android/chrome/aboutDownloads.dtd
new file mode 100644
index 0000000000..11c299e9d0
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutDownloads.dtd
@@ -0,0 +1,15 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY aboutDownloads.title                      "Llwythi">
+<!ENTITY aboutDownloads.header                     "Eich Llwythi">
+<!ENTITY aboutDownloads.empty                      "Dim Llwythi">
+
+<!ENTITY aboutDownloads.open                       "Agor">
+<!ENTITY aboutDownloads.remove                     "Dileu">
+<!ENTITY aboutDownloads.removeAll                  "Dileu Popeth">
+<!ENTITY aboutDownloads.pause                      "Oedi">
+<!ENTITY aboutDownloads.resume                     "Ailgychwyn">
+<!ENTITY aboutDownloads.cancel                     "Diddymu">
+<!ENTITY aboutDownloads.retry                      "Ceisio eto">
diff --git a/l10n-cy/mobile/android/chrome/aboutDownloads.properties b/l10n-cy/mobile/android/chrome/aboutDownloads.properties
new file mode 100644
index 0000000000..81bd35ba68
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutDownloads.properties
@@ -0,0 +1,17 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (downloadMessage.deleteAll):
+# Semicolon-separated list of plural forms. See:
+# http://developer.mozilla.org/en/docs/Localization_and_Plurals
+downloadMessage.deleteAll=Peidio dileu llwythi?;Dileu #1 llwyth?;Dileu #1 lwyth?;Dileu #1 llwyth?;Dileu #1 llwyth?;Dileu #1 llwyth?
+
+downloadAction.deleteAll=Dileu Popeth
+
+downloadState.downloading=Llwytho i lawr…
+downloadState.canceled=Diddymwyd
+downloadState.failed=Methiant
+downloadState.paused=Oedwyd
+downloadState.starting=Cychwyn…
+downloadState.unknownSize=Maint anhysbys
diff --git a/l10n-cy/mobile/android/chrome/aboutHome.dtd b/l10n-cy/mobile/android/chrome/aboutHome.dtd
new file mode 100644
index 0000000000..af318c06ae
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutHome.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- This string should be kept in sync with the home_title string
+     in android_strings.dtd -->
+
+<!ENTITY abouthome.title                  "Cartref &brandShortName;">
diff --git a/l10n-cy/mobile/android/chrome/aboutLogins.dtd b/l10n-cy/mobile/android/chrome/aboutLogins.dtd
new file mode 100644
index 0000000000..eb3f1582fb
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutLogins.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
+   %brandDTD;
+<!ENTITY aboutLogins.title                       "Mewngofnodion">
+<!ENTITY aboutLogins.update                      "Diweddaru">
+<!ENTITY aboutLogins.emptyLoginText              "Cadw eich mewngofnodi'n ddiogel">
+<!ENTITY aboutLogins.emptyLoginHint              "Bydd mewngofnodi a manylion rydych yn eu cadw wrth ddefnyddio &brandShortName; yn ymddangos yma.">
diff --git a/l10n-cy/mobile/android/chrome/aboutLogins.properties b/l10n-cy/mobile/android/chrome/aboutLogins.properties
new file mode 100644
index 0000000000..bc2e2f2712
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutLogins.properties
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+loginsMenu.showPassword=Dangos cyfrinair
+loginsMenu.copyPassword=Copïo'r cyfrinair
+loginsMenu.copyUsername=Copïo'r enw defnyddiwr
+loginsMenu.editLogin=Golygu'r mewngofnod
+loginsMenu.delete=Dileu
+
+loginsMenu.deleteAll=Dileu'r Cyfan
+
+loginsDialog.confirmDelete=Dileu'r mewngofnodiad hwn?
+loginsDialog.confirmDeleteForFxaUser=Dileu'r mewngofnodiad?\n\nGall hyn effeithio ar fewngofnodion wedi'u cydweddu.
+loginsDialog.confirmDeleteAll=Dileu pob mewngofnod?
+loginsDialog.confirmDeleteAllForFxaUser=Dileu pob mewngofnodiad?\n\nGall hyn effeithio ar fewngofnodion wedi'u cydweddu.
+loginsDialog.copy=Copïo
+loginsDialog.confirm=Iawn
+loginsDialog.cancel=Diddymu
+
+editLogin.fallbackTitle=Golygu'r Mewngofnod
+editLogin.saved1=Mewngofnodion wedi eu cadw
+editLogin.couldNotSave=Nid oedd modd cadw'r newidiadau
+
+loginsDetails.copyFailed=Methodd y copïo
+loginsDetails.passwordCopied=Wedi copïo'r cyfrinair
+loginsDetails.usernameCopied=Enw defnyddiwr wedi ei gopïo
+loginsDetails.deleted=Mewngofnod wedi ei ddileu
+
+loginsDetails.deletedAll=Pob mewngofnod wedi'u dileu
+
+password-btn.show=Dangos
+password-btn.hide=Cuddio
diff --git a/l10n-cy/mobile/android/chrome/aboutPrivateBrowsing.dtd b/l10n-cy/mobile/android/chrome/aboutPrivateBrowsing.dtd
new file mode 100644
index 0000000000..2764c26fd1
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/aboutPrivateBrowsing.dtd
@@ -0,0 +1,25 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY privatebrowsingpage.title "Pori Preifat">
+<!-- Localisation note: the plus sign here is a shorthand way of expressing the word "and". Contextually the privatebrowsingpage.title.private string
+                        is used as a title, with the privatebrowsingpage.title string preceding it but on a separate line.
+                        So the final line will say "Private Browsing + Tracking Protection". -->
+
+<!ENTITY privatebrowsingpage.title.private "+ Diogelwch Rhag Tracio">
+<!-- Localization note (privatebrowsingpage.title.normal1): "Private Browsing"
+     is capitalized in English to be consistent with our existing uses of the
+     term. -->
+<!ENTITY privatebrowsingpage.title.normal1 "Nid ydych yn Pori'n Breifat">
+
+<!ENTITY privatebrowsingpage.description.trackingProtection "Mae &brandShortName; yn rhwystro rhannau o'r dudalen gall fod yn tracio eich pori.">
+<!ENTITY privatebrowsingpage.description.privateDetails "Byddwn ni ddim yn cofio unrhyw hanes ond bydd unrhyw ffeiliau rydych wedi eu llwytho i lawr a nodau tudalen yn cael eu cadw ar eich dyfais.">
+<!-- Localization note (privatebrowsingpage.description.normal2): "Private
+     Browsing is capitalized in English to be consistent with our existing uses
+     of the term. -->
+
+<!ENTITY privatebrowsingpage.description.normal2 "Wrth Bori'n Breifat, ni fyddwn yn cadw eich hanes pori na chwcis. Ond bydd unrhyw ffeiliau rydych wedi eu llwytho i lawr a nodau tudalen yn cael eu cadw ar eich dyfais.">
+
+<!ENTITY privatebrowsingpage.link.private "Eisiau gwybod mwy?">
+<!ENTITY privatebrowsingpage.link.normal "Agor mewn tab preifat newydd">
diff --git a/l10n-cy/mobile/android/chrome/browser.properties b/l10n-cy/mobile/android/chrome/browser.properties
new file mode 100644
index 0000000000..51a9fec64b
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/browser.properties
@@ -0,0 +1,476 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addonsConfirmInstall.title=Gosod Ychwanegyn
+addonsConfirmInstall.install=Gosod
+
+addonsConfirmInstallUnsigned.title=Ychwanegyn heb ei wirio
+addonsConfirmInstallUnsigned.message=Hoffai'r wefan osod ychwanegyn sydd heb ei wirio. Cymerwch ofal.
+
+# Alerts
+alertAddonsDownloading=Llwytho ychwanegyn i lawr
+alertAddonsInstalledNoRestart.message=Gosod wedi ei gwblhau
+
+# LOCALIZATION NOTE (alertAddonsInstalledNoRestart.action2): Ideally, this string is short (it's a
+# button label) and upper-case, to match Google and Android's convention.
+alertAddonsInstalledNoRestart.action2=YCHWANEGION
+
+alertDownloadsStart2=Llwytho i lawr wedi cychwyn
+alertDownloadsDone2=Llwythi cyflawn
+alertDownloadsToast=Llwytho i lawr wedi cychwyn…
+alertDownloadsPause=Oedi
+alertDownloadsResume=Ailgychwyn
+alertDownloadsCancel=Diddymu
+# LOCALIZATION NOTE (alertDownloadSucceeded): This text is shown as a snackbar inside the app after a
+# successful download. %S will be replaced by the file name of the download.
+alertDownloadSucceeded=%S wedi ei lwytho i lawr
+# LOCALIZATION NOTE (downloads.disabledInGuest): This message appears in a toast
+# when the user tries to download something in Guest mode.
+downloads.disabledInGuest=Mae llwytho i lawr wedi ei atal yn ystod sesiynau gwestai
+
+# LOCALIZATION NOTE (alertSearchEngineAddedToast, alertSearchEngineErrorToast, alertSearchEngineDuplicateToast)
+# %S will be replaced by the name of the search engine (exposed by the current page)
+# that has been added; for example, 'Google'.
+alertSearchEngineAddedToast=Mae '%S' wedi ei ychwanegu fel peiriant chwilio
+alertSearchEngineErrorToast=Methwyd ychwanegu '%S' fel peiriant chwilio
+alertSearchEngineDuplicateToast=Mae '%S' eisoes yn un o'ch peiriannau chwilio
+
+# LOCALIZATION NOTE (alertShutdownSanitize): This text is shown as a snackbar during shutdown if the
+# user has enabled "Clear private data on exit".
+alertShutdownSanitize=Clirio data preifat…
+
+alertPrintjobToast=Argraffu…
+
+download.blocked=Methu llwytho'r ffeil i lawr
+
+addonError.titleError=Gwall
+addonError.titleBlocked=Ychwanegyn wedi ei rwystro
+addonError.learnMore=Dysgu rhagor
+
+# LOCALIZATION NOTE (unsignedAddonsDisabled.title, unsignedAddonsDisabled.message):
+# These strings will appear in a dialog when Firefox detects that installed add-ons cannot be verified.
+unsignedAddonsDisabled.title=Ychwanegion heb eu gwirio
+unsignedAddonsDisabled.message=Nid oedd modd gwirio un neu fwy o'ch ychwanegion ac mae nhw wedi eu hanalluogi.
+unsignedAddonsDisabled.dismiss=Gwrthod
+unsignedAddonsDisabled.viewAddons=Gweld yr ychwanegion
+
+# LOCALIZATION NOTE (addonError-1, addonError-2, addonError-3, addonError-4, addonError-5):
+# #1 is the add-on name, #2 is the add-on host, #3 is the application name
+addonError-1=Nid oedd modd llwytho'r ychwanegyn i lawr oherwydd methiant cysylltiad ar #2.
+addonError-2=Nid oedd modd gosod yr ychwanegyn o #2 am nad yw'n gytûn a'r ychwanegyn disgwyliwyd, #3.
+addonError-3=Nid oedd modd llwytho'r ychwanegyn i lawr o #2 oherwydd ei fod yn edrych yn llwgr.
+addonError-4=Nid oedd modd gosod #1 gan nad oedd #3 yn gallu newid y linell angenrheidiol.
+addonError-5=Mae #3 wedi rhwystro #2 rhag gosod ychwanegyn heb ei wirio.
+
+# LOCALIZATION NOTE (addonLocalError-1, addonLocalError-2, addonLocalError-3, addonLocalError-4, addonLocalError-5, addonErrorIncompatible, addonErrorBlocklisted):
+# #1 is the add-on name, #3 is the application name, #4 is the application version
+addonLocalError-1=Nid oedd modd gosod yr ychwanegyn oherwydd gwall system.
+addonLocalError-2=Nid oedd modd gosod yr ychwanegyn am nad yw'n gytûn a'r ychwanegyn #3 disgwyliwyd.
+addonLocalError-3=Nid oedd modd gosod yr ychwanegyn am ei fod yn edrych yn llwgr.
+addonLocalError-4=Nid oedd modd gosod #1 gan nad oedd #3 yn gallu newid y linell angenrheidiol.
+addonLocalError-5=Nid oedd modd gosod yr ychwanegyn am nad yw wedi ei wirio.
+addonErrorIncompatible=Nid oedd modd gosod #1 gan nad yw'n cydweddu â #3 #4.
+addonErrorBlocklisted=Nid oedd modd gosod #1 am fod risg uchel iddo achosi problemau sefydlogrwydd a diogelwch.
+
+# Notifications
+notificationRestart.normal=Ailgychwyn i gwblhau'r newidiadau.
+notificationRestart.blocked=Ychwanegyn anniogel wedi ei osod. Ailgychwyn i'w analluogi.
+notificationRestart.button=Ailgychwyn
+doorhanger.learnMore=Dysgu rhagor
+
+# Popup Blocker
+
+# LOCALIZATION NOTE (popup.message): Semicolon-separated list of plural forms.
+# #1 is brandShortName and #2 is the number of pop-ups blocked.
+popup.message=Mae #1 wedi rhwystro'r wefan rhag agor llamlen. Hoffech chi ei dangos?;Mae #1 wedi rhwystro'r wefan rhag agor #2 llamlen. Hoffech chi eu dangos?
+popup.dontAskAgain=Peidio gofyn eto am y wefan
+popup.show=Dangos
+popup.dontShow=Peidio dangos
+
+# SafeBrowsing
+safeBrowsingDoorhanger=Mae'r wefan yn hysbys fel un sy'n cynnwys drwgwar neu geisio twyllo. Byddwch ofalus.
+
+# LOCALIZATION NOTE (blockPopups.label2): Label that will be used in
+# site settings dialog.
+blockPopups.label2=Llamlenni
+
+# XPInstall
+xpinstallPromptWarning2=Rhwystrodd %S y wefan (%S) rhag gofyn i chi osod meddalwedd ar eich dyfais.
+xpinstallPromptWarningLocal=Rhwystrodd %S yr ychwanegyn yma (%S) rhag cael ei osod ar eich dyfais.
+xpinstallPromptWarningDirect=Rhwystrodd %S ychwanegyn rhag cael ei osod ar eich dyfais.
+xpinstallPromptAllowButton=Caniatáu
+xpinstallDisabledMessageLocked=Mae gosod meddalwedd wedi ei analluogi gan eich gweinyddwr system.
+xpinstallDisabledMessage2=Mae gosod meddalwedd wedi ei analluogi ar hyn o bryd. Cliciwch Galluogi a cheisiwch eto.
+xpinstallDisabledButton=Galluogi
+
+# LOCALIZATION NOTE (webextPerms.header)
+# This string is used as a header in the webextension permissions dialog,
+# %S is replaced with the localized name of the extension being installed.
+# See https://bug1308309.bmoattachments.org/attachment.cgi?id=8814612
+# for an example of the full dialog.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webextPerms.header=Ychwanegu %S?
+
+# LOCALIZATION NOTE (webextPerms.listIntro)
+# This string will be followed by a list of permissions requested
+# by the webextension.
+webextPerms.listIntro=Mae angen eich caniatâd i:
+webextPerms.add.label=Ychwanegu
+webextPerms.cancel.label=Diddymu
+
+# LOCALIZATION NOTE (webextPerms.updateText)
+# %S is replaced with the localized name of the updated extension.
+webextPerms.updateText=Mae %S wedi ei ddiweddaru. Rhaid cymeradwyo'r caniatâd newydd cyn i'r fersiwn mwy diweddar gael ei osod. Bydd dewis “Diddymu” yn cadw eich ychwanegyn cyfredol.
+
+webextPerms.updateAccept.label=Diweddaru
+
+# LOCALIZATION NOTE (webextPerms.optionalPermsHeader)
+# %S is replaced with the localized name of the extension requesting new
+# permissions.
+webextPerms.optionalPermsHeader=Mae %S yn gofyn am ganiatâd ychwanegol.
+webextPerms.optionalPermsListIntro=Mae eisiau:
+webextPerms.optionalPermsAllow.label=Caniatáu
+webextPerms.optionalPermsDeny.label=Gwrthod
+
+webextPerms.description.bookmarks=Darllen a newid nodau tudalen
+webextPerms.description.browserSettings=Darllen a newid gosodiadau'r porwr
+webextPerms.description.browsingData=Clirio'r hanes pori diweddar, cwcis a data cysylltiedig
+webextPerms.description.clipboardRead=Estyn data o'r clipfwrdd
+webextPerms.description.clipboardWrite=Mewnbynnu data i'r clipfwrdd
+webextPerms.description.devtools=Estyn offer datblygwyr i gael mynediad at eich data mewn tabiau agored
+webextPerms.description.downloads=Llwytho i lawr, darllen ffeiliau a newid hanes llwytho i lawr y porwr
+webextPerms.description.downloads.open=Agor ffeiliau a llwythwyd i lawr i'ch cyfrifiadur
+webextPerms.description.find=Darllen testun yr holl dabiau sydd ar agor
+webextPerms.description.geolocation=Mynediad i'ch lleoliad
+webextPerms.description.history=Mynediad at eich hanes pori
+webextPerms.description.management=Monitro'r defnydd o estyniadau a rheoli themâu
+# LOCALIZATION NOTE (webextPerms.description.nativeMessaging)
+# %S will be replaced with the name of the application
+webextPerms.description.nativeMessaging=Cyfnewid negeseuon gyda rhaglenni ar wahân i %S
+webextPerms.description.notifications=Dangos hysbysiadau i chi
+webextPerms.description.privacy=Darllen a newid gosodiadau preifatrwydd
+webextPerms.description.proxy=Rheoli gosodiadau dirprwy'r porwr
+webextPerms.description.sessions=Mynediad at y tabiau caewyd yn ddiweddar
+webextPerms.description.tabs=Mynediad at dabiau'r porwyr
+webextPerms.description.topSites=Mynediad at eich hanes pori
+webextPerms.description.webNavigation=Cael mynediad at weithgaredd wrth lywio
+
+webextPerms.hostDescription.allUrls=Cael mynediad i'ch data ar gyfer pob gwefan
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.wildcard)
+# %S will be replaced by the DNS domain for which a webextension
+# is requesting access (e.g., mozilla.org)
+webextPerms.hostDescription.wildcard=Cael mynediad i'ch data ym mhob gwefan ym mharth %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManyWildcards):
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# domains for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManyWildcards=Peidio cael mynediad i'ch data mewn parthau eraill;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 barth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall;Cael mynediad i'ch data mewn #1 parth arall
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.oneSite)
+# %S will be replaced by the DNS host name for which a webextension
+# is requesting access (e.g., www.mozilla.org)
+webextPerms.hostDescription.oneSite=Cael mynediad at eich data yn %S
+
+# LOCALIZATION NOTE (webextPerms.hostDescription.tooManySites)
+# Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 will be replaced by an integer indicating the number of additional
+# hosts for which this webextension is requesting permission.
+webextPerms.hostDescription.tooManySites=Peidio cael mynediad i'ch data mewn gwefannau eraill;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 wefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall;Cael mynediad i'ch data mewn #1 gwefan arall
+
+
+# Site Identity
+identity.identified.verifier=Dilyswyd gan: %S
+identity.identified.verified_by_you=Rydych wedi ychwanegu eithriad diogelwch i'r wefan
+identity.identified.state_and_country=%S, %S
+
+# Geolocation UI
+geolocation.allow=Rhannu
+geolocation.dontAllow=Peidio rhannu
+# LOCALIZATION NOTE (geolocation.location): Label that will be used in
+# site settings dialog.
+geolocation.location=Lleoliad
+
+# Desktop notification UI
+desktopNotification2.allow=Bob tro
+desktopNotification2.dontAllow=Byth
+# LOCALIZATION NOTE (desktopNotification.notifications): Label that will be
+# used in site settings dialog.
+desktopNotification.notifications=Hysbysiadau
+
+# Imageblocking
+imageblocking.downloadedImage=Dadrwystrwyd delwedd
+imageblocking.showAllImages=Dangos y Cyfan
+
+# New Tab Popup
+# LOCALIZATION NOTE (newtabpopup, newprivatetabpopup): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 number of tabs
+newtabpopup.opened=Dim tabiau newydd wedi eu hagor;#1 tab newydd wedi ei agor;#1 dab newydd wedi eu hagor;#1 thab newydd wedi eu hagor;#1 thab newydd wedi eu hagor;#1 tab newydd wedi eu hagor
+newprivatetabpopup.opened=Agorwyd tab preifat newydd;#1 agorwyd tabiau preifat newydd
+
+# LOCALIZATION NOTE (newtabpopup.switch): Ideally, this string is short (it's a
+# button label) and upper-case, to match Google and Android's convention.
+newtabpopup.switch=NEWID
+
+# Undo close tab toast
+# LOCALIZATION NOTE (undoCloseToast.message): This message appears in a toast
+# when the user closes a tab. %S is the title of the tab that was closed.
+undoCloseToast.message=Cau %S
+
+# Private Tab closed message
+# LOCALIZATION NOTE (privateClosedMessage.message): This message appears
+# when the user closes a private tab.
+privateClosedMessage.message=Pori Preifat wedi Cau
+
+# LOCALIZATION NOTE (undoCloseToast.messageDefault): This message appears in a
+# toast when the user closes a tab if there is no title to display.
+undoCloseToast.messageDefault=Tab wedi cau
+
+# LOCALIZATION NOTE (undoCloseToast.action2): Ideally, this string is short (it's a
+# button label) and upper-case, to match Google and Android's convention.
+undoCloseToast.action2=DADWNEUD
+
+# Offline web applications
+offlineApps.ask=Caniatáu i %S gadw data ar eich dyfais ar gyfer defnydd all-lein?
+offlineApps.dontAskAgain=Peidio gofyn eto am y wefan
+offlineApps.allow=Caniatáu
+offlineApps.dontAllow2=Peidio caniatáu
+
+# LOCALIZATION NOTE (offlineApps.offlineData): Label that will be used in
+# site settings dialog.
+offlineApps.offlineData=Data All-lein
+
+# LOCALIZATION NOTE (password.logins): Label that will be used in
+ # site settings dialog.
+password.logins=Mewngofnodion
+# LOCALIZATION NOTE (password.save): This should match
+# saveButton in passwordmgr.properties
+password.save=Cadw
+# LOCALIZATION NOTE (password.dontSave): This should match
+# dontSaveButton in passwordmgr.properties
+password.dontSave=Peidio â chadw
+
+# LOCALIZATION NOTE (browser.menu.showCharacterEncoding): Set to the string
+# "true" (spelled and capitalized exactly that way) to show the "Character
+# Encoding" menu in the site menu. Any other value will hide it. Without this
+# setting, the "Character Encoding" menu must be enabled via Preferences.
+# This is not a string to translate. If users frequently use the "Character Encoding"
+# menu, set this to "true". Otherwise, you can leave it as "false".
+browser.menu.showCharacterEncoding=false
+
+# Text Selection
+selectionHelper.textCopied=Testun wedi ei gopïo i'r clipfwrdd
+
+# Casting
+# LOCALIZATION NOTE (casting.sendToDevice): Label that will be used in the
+# dialog/prompt.
+casting.sendToDevice=Anfon i Ddyfais
+
+# Context menu
+contextmenu.openInNewTab=Agor Dolen mewn Tab Newydd
+contextmenu.openInPrivateTab=Agor Dolen mewn Tab Preifat
+contextmenu.share=Rhannu
+contextmenu.copyLink=Copïo Dolen
+contextmenu.shareLink=Rhannu Dolen
+contextmenu.bookmarkLink=Dolen Nod Tudalen
+contextmenu.copyEmailAddress=Copïo Cyfeiriad E-bost
+contextmenu.shareEmailAddress=Rhannu Cyfeiriad E-bost
+contextmenu.copyPhoneNumber=Copïo Rhif Ffôn
+contextmenu.sharePhoneNumber=Rhannu Rhif Ffôn
+contextmenu.fullScreen=Sgrin Lawn
+contextmenu.viewImage=Edrych ar Ddelwedd
+contextmenu.copyImageLocation=Copïo Lleoliad Delwedd
+contextmenu.shareImage=Cadw Delwedd
+# LOCALIZATION NOTE (contextmenu.search):
+# The label of the contextmenu item which allows you to search with your default search engine for
+# the text you have selected. %S is the name of the search engine. For example, "Google".
+contextmenu.search=Chwilio gyda %S
+contextmenu.saveImage=Cadw Delwedd
+contextmenu.showImage=Dangos Delwedd
+contextmenu.setImageAs=Gosod Delwedd Fel
+# LOCALIZATION NOTE (contextmenu.addSearchEngine3): This string should be rather short. If it is
+# significantly longer than the translation for the "Paste" action then this might trigger an
+# Android bug positioning the floating text selection partially off the screen. This issue heavily
+# depends on the screen size and the specific translations. For English "Paste" / "Add search engine"
+# is working while "Paste" / "Add as search engine" triggers the bug. See bug 1262098 for more details.
+# Manual testing the scenario described in bug 1262098 is highly recommended.
+contextmenu.addSearchEngine3=Ychwanegu Peiriant Chwilio
+contextmenu.playMedia=Chwarae
+contextmenu.pauseMedia=Oedi
+contextmenu.showControls2=Dangos Rheolyddion
+contextmenu.mute=Mudo
+contextmenu.unmute=Dadfudo
+contextmenu.saveVideo=Cadw Fideo
+contextmenu.saveAudio=Cadw Sain
+contextmenu.addToContacts=Creu Cysylltiadau
+# LOCALIZATION NOTE (contextmenu.sendToDevice):
+# The label that will be used in the contextmenu and the pageaction
+contextmenu.sendToDevice=Anfon i Ddyfais
+
+contextmenu.copy=Copïo
+contextmenu.cut=Torri
+contextmenu.selectAll=Dewis Popeth
+contextmenu.paste=Gludo
+
+contextmenu.call=Galw
+
+#Input widgets UI
+inputWidgetHelper.date=Dewis dyddiad
+inputWidgetHelper.datetime-local=Dewis dyddiad ac amser
+inputWidgetHelper.time=Dewis amser
+inputWidgetHelper.week=Dewis wythnos
+inputWidgetHelper.month=Dewis mis
+inputWidgetHelper.cancel=Diddymu
+inputWidgetHelper.set=Gosod
+inputWidgetHelper.clear=Clirio
+
+# Web Console API
+stacktrace.anonymousFunction=<anhysbys>
+stacktrace.outputMessage=Stacio'r ôl o %S, swyddogaeth %S, llinell %S.
+timer.start=%S: amserydd wedi cychwyn
+
+# LOCALIZATION NOTE (timer.end):
+# This string is used to display the result of the console.timeEnd() call.
+# %1$S=name of timer, %2$S=number of milliseconds
+timer.end=%1$S: %2$Sms
+
+clickToPlayPlugins.activate=Gweithredu
+clickToPlayPlugins.dontActivate=Peidio gweithredu
+# LOCALIZATION NOTE (clickToPlayPlugins.plugins): Label that
+# will be used in site settings dialog.
+clickToPlayPlugins.plugins=Ategion
+
+# Site settings dialog
+
+masterPassword.incorrect=Cyfrinair anghywir
+
+# Debugger
+# LOCALIZATION NOTE (remoteIncomingPromptTitle): The title displayed on the
+# dialog that prompts the user to allow the incoming connection.
+remoteIncomingPromptTitle=Cysylltiad i Fewn
+# LOCALIZATION NOTE (remoteIncomingPromptUSB): The message displayed on the
+# dialog that prompts the user to allow an incoming USB connection.
+remoteIncomingPromptUSB=Caniatáu cysylltiad dadfygio USB?
+# LOCALIZATION NOTE (remoteIncomingPromptUSB): The message displayed on the
+# dialog that prompts the user to allow an incoming TCP connection.
+remoteIncomingPromptTCP=Caniatáu cysylltiad dadfygio pell o %1$S:%2$S? Mae'r cysylltiad angen cod QR i gael ei sganio er mwyn dilysu tysytysgrif y ddyfais pell. Gallwch osgoi sganio yn y dyfodol drwy gofio'r ddyfais.
+# LOCALIZATION NOTE (remoteIncomingPromptDeny): This button will deny an
+# an incoming remote debugger connection.
+remoteIncomingPromptDeny=Gwrthod
+# LOCALIZATION NOTE (remoteIncomingPromptAllow): This button will allow an
+# an incoming remote debugger connection.
+remoteIncomingPromptAllow=Caniatáu
+# LOCALIZATION NOTE (remoteIncomingPromptScan): This button will start a QR
+# code scanner to authenticate an incoming remote debugger connection.  The
+# connection will be allowed assuming the scan succeeds.
+remoteIncomingPromptScan=Sganio
+# LOCALIZATION NOTE (remoteIncomingPromptScanAndRemember): This button will
+# start a QR code scanner to authenticate an incoming remote debugger
+# connection.  The connection will be allowed assuming the scan succeeds, and
+# the other endpoint's certificate will be saved to skip future scans for this
+# client.
+remoteIncomingPromptScanAndRemember=Sganio a Chofio
+# LOCALIZATION NOTE (remoteQRScanFailedPromptTitle): The title displayed in a
+# dialog when we are unable to complete the QR code scan for an incoming remote
+# debugging connection.
+remoteQRScanFailedPromptTitle=Methodd y Sgan QR
+# LOCALIZATION NOTE (remoteQRScanFailedPromptMessage): The message displayed in
+# a dialog when we are unable to complete the QR code scan for an incoming
+# remote debugging connection.
+remoteQRScanFailedPromptMessage=Methu sganio'r cod QR ar gyfer dadfygio pell. Gwiriwch fod y rhaglen Sganio Cod Bar wedi ei osod a cheisiwch ailgysylltu.
+# LOCALIZATION NOTE (remoteQRScanFailedPromptOK): This button dismisses the
+# dialog that appears when we are unable to complete the QR code scan for an
+# incoming remote debugging connection.
+remoteQRScanFailedPromptOK=Iawn
+
+# Helper apps
+helperapps.open=Agor
+helperapps.openWithApp2=Agor gydag Ap %S
+helperapps.openWithList2=Agor gydag Ap
+helperapps.always=Bob tro
+helperapps.never=Byth
+helperapps.pick=Cwblhau'r weithred gyda
+helperapps.saveToDisk=Llwytho
+helperapps.alwaysUse=Bob tro
+helperapps.useJustOnce=Unwaith
+
+# LOCALIZATION NOTE (getUserMedia.shareCamera.message, getUserMedia.shareMicrophone.message, getUserMedia.shareCameraAndMicrophone.message, getUserMedia.sharingCamera.message, getUserMedia.sharingMicrophone.message, getUserMedia.sharingCameraAndMicrophone.message): %S is the website origin (e.g. www.mozilla.org)
+getUserMedia.shareCamera.message = Hoffech chi rannu eich camera gyda %S?
+getUserMedia.shareMicrophone.message = Hoffech chi rannu eich meicroffon gyda %S?
+getUserMedia.shareCameraAndMicrophone.message = Hoffech chi rannu eich camera a meicroffon gyda %S?
+getUserMedia.denyRequest.label = Peidio Rhannu
+getUserMedia.shareRequest.label = Rhannu
+getUserMedia.videoSource.default = Camera %S
+getUserMedia.videoSource.frontCamera = Camera'n wynebu ymlaen
+getUserMedia.videoSource.backCamera = Camera'n wynebu nôl
+getUserMedia.videoSource.none = Dim Fideo
+getUserMedia.videoSource.tabShare = Dewis tab i'w ffrydio
+getUserMedia.videoSource.prompt = Ffynhonnell fideo
+getUserMedia.audioDevice.default = Meicroffon %S
+getUserMedia.audioDevice.none = Dim Sain
+getUserMedia.audioDevice.prompt = Meicroffon yn cael ei ddefnyddio
+getUserMedia.sharingCamera.message2 = Camera ymlaen
+getUserMedia.sharingMicrophone.message2 = Microffon ymlaen
+getUserMedia.sharingCameraAndMicrophone.message2 = Camera a meicroffon ymlaen
+getUserMedia.blockedCameraAccess = Mae'r camera wedi ei rwystro.
+getUserMedia.blockedMicrophoneAccess = Mae'r meicroffon wedi ei rwystro.
+getUserMedia.blockedCameraAndMicrophoneAccess = Mae'r camera a'r meicroffon wedi ei rwystro.
+
+# LOCALIZATION NOTE (userContextPersonal.label,
+#                    userContextWork.label,
+#                    userContextShopping.label,
+#                    userContextBanking.label,
+#                    userContextNone.label):
+# These strings specify the four predefined contexts included in support of the
+# Contextual Identity / Containers project. Each context is meant to represent
+# the context that the user is in when interacting with the site. Different
+# contexts will store cookies and other information from those sites in
+# different, isolated locations. You can enable the feature by typing
+# about:config in the URL bar and changing privacy.userContext.enabled to true.
+# Once enabled, you can open a new tab in a specific context by clicking
+# File > New Container Tab > (1 of 4 contexts). Once opened, you will see these
+# strings on the right-hand side of the URL bar.
+# In android this will be only exposed by web extensions
+userContextPersonal.label = Personol
+userContextWork.label = Gwaith
+userContextBanking.label = Bancio
+userContextShopping.label = Siopa
+
+# LOCALIZATION NOTE (readerMode.toolbarTip):
+# Tip shown to users the first time we hide the reader mode toolbar.
+readerMode.toolbarTip=Tapiwch y sgrin i ddangos dewisiadau darllen
+
+#Open in App
+openInApp.pageAction = Agor o fewn Ap
+openInApp.ok = Iawn
+openInApp.cancel = Diddymu
+
+#Tab sharing
+tabshare.title = "Dewis tab i'w ffrydio"
+#Tabs in context menus
+browser.menu.context.default = Dolen
+browser.menu.context.img = Delwedd
+browser.menu.context.video = Fideo
+browser.menu.context.audio = Sain
+browser.menu.context.tel = Ffôn
+browser.menu.context.mailto = E-bost
+
+# "Subscribe to page" prompts created in FeedHandler.js
+feedHandler.chooseFeed=Dewis llif
+feedHandler.subscribeWith=Tanysgrifio gyda
+
+# LOCALIZATION NOTE (nativeWindow.deprecated):
+# This string is shown in the console when someone uses deprecated NativeWindow apis.
+# %1$S=name of the api that's deprecated, %2$S=New API to use. This may be a url to
+# a file they should import or the name of an api.
+nativeWindow.deprecated=Mae %1$S yn anghymarus. Defnyddiwch %2$S
+
+# Vibration API permission prompt
+vibrationRequest.message = Caniatáu'r wefan yma ddirgrynu eich dyfais?
+vibrationRequest.denyButton = Peidio caniatáu
+vibrationRequest.allowButton = Caniatáu
diff --git a/l10n-cy/mobile/android/chrome/config.dtd b/l10n-cy/mobile/android/chrome/config.dtd
new file mode 100644
index 0000000000..925ea3bfba
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/config.dtd
@@ -0,0 +1,21 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+
+<!ENTITY toolbar.searchPlaceholder     "Chwilio">
+
+<!ENTITY newPref.namePlaceholder       "Enw">
+
+<!ENTITY newPref.valueBoolean          "Booleaidd">
+<!ENTITY newPref.valueString           "Llinell">
+<!ENTITY newPref.valueInteger          "Cyfanrif">
+
+<!ENTITY newPref.stringPlaceholder     "Rhowch linyn">
+<!ENTITY newPref.numberPlaceholder     "Rhowch rif">
+
+<!ENTITY newPref.toggleButton          "Toglo">
+<!ENTITY newPref.cancelButton          "Diddymu">
+
+<!ENTITY contextMenu.copyPrefName      "Copïo Enw">
+<!ENTITY contextMenu.copyPrefValue     "Copïo Gwerth">
diff --git a/l10n-cy/mobile/android/chrome/config.properties b/l10n-cy/mobile/android/chrome/config.properties
new file mode 100644
index 0000000000..a87549e7a0
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/config.properties
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+newPref.createButton=Creu
+newPref.changeButton=Newid
+
+pref.toggleButton=Toglo
+pref.resetButton=Ailosod
diff --git a/l10n-cy/mobile/android/chrome/devicePrompt.properties b/l10n-cy/mobile/android/chrome/devicePrompt.properties
new file mode 100644
index 0000000000..21fbdaea2f
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/devicePrompt.properties
@@ -0,0 +1,5 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+deviceMenu.title=Dyfeisiau Gerllaw
diff --git a/l10n-cy/mobile/android/chrome/passwordmgr.properties b/l10n-cy/mobile/android/chrome/passwordmgr.properties
new file mode 100644
index 0000000000..849962bf0f
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/passwordmgr.properties
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# String will be replaced by brandShortName.
+saveLogin=Hoffech chi i %S gofio'r mewngofnodiad?
+rememberButton=Cofio
+neverButton=Byth
+
+# String is the login's hostname
+updatePassword=Diweddaru cyfrinair wedi ei gadw ar gyfer %S?
+updatePasswordNoUser=Diweddaru cyfrinair heb ei gadw ar gyfer y mewngofnodiad hwn?
+updateButton=Diweddaru
+dontUpdateButton=Peidio diweddaru
+
+userSelectText2=Dewis pa fewngofnod i'w ddiweddaru:
+passwordChangeTitle=Cadarnhau Newid Cyfrinair
+
+username=Enw Defnyddiwr
+password=Cyfrinair
diff --git a/l10n-cy/mobile/android/chrome/phishing.dtd b/l10n-cy/mobile/android/chrome/phishing.dtd
new file mode 100644
index 0000000000..3fc9ca8274
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/phishing.dtd
@@ -0,0 +1,27 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY safeb.palm.accept.label "Allan o fan hyn!">
+<!ENTITY safeb.palm.decline.label "Anwybyddu'r rhybudd">
+<!ENTITY safeb.palm.reportPage.label "Pam oedd y dudalen hon wedi ei rhwystro?">
+<!-- Localization note (safeb.palm.advisory.desc) - Please don't translate <a id="advisory_provider"/> tag.  It will be replaced at runtime with advisory link-->
+<!ENTITY safeb.palm.advisory.desc "Nodyn cynghorol wedi ei ddarparu gan <a id='advisory_provider'/>">
+
+<!ENTITY safeb.blocked.malwarePage.title "Adroddwyd Ymosodiad Tudalen!">
+<!-- Localization note (safeb.blocked.malware.shortDesc) - Please don't translate the contents of the <span id="malware_sitename"/> tag.  It will be replaced at runtime with a domain name (e.g. www.badsite.com) -->
+<!ENTITY safeb.blocked.malwarePage.shortDesc "Mae'r dudalen hon <span id='malware_sitename'/> wedi ei chofnodi fel tudalen ymosod ac mae wedi ei rhwystro yn seiliedig ar eich dewisiadau diogelwch.">
+<!ENTITY safeb.blocked.malwarePage.longDesc "<p>Mae tudalennau ymosod yn ceisio gosod rhaglenni sy'n dwyn gwybodaeth breifat, defnyddio eich cyfrifiadur i ymosod ar eraill, neu ddifrodi eich system.</p><p>Mae rhai tudalennau ymosod yn fwriadol yn dosbarthu meddalwedd niweidiol, ond mae llawer yn cael eu cyfaddawdu heb yn wybod neu ganiatâd eu perchnogion.</p>">
+
+<!ENTITY safeb.blocked.phishingPage.title3 "Gwefan Twyllodrus!">
+<!-- Localization note (safeb.blocked.phishingPage.shortDesc3) - Please don't translate the contents of the <span id="phishing_sitename"/> tag. It will be replaced at runtime with a domain name (e.g. www.badsite.com) -->
+<!ENTITY safeb.blocked.phishingPage.shortDesc3 "Mae'r dudalen we hon <span id='phishing_sitename'/> wedi ei chofnodi fel tudalen twyllodrus ac mae wedi ei rhwystro yn seiliedig ar eich dewisiadau diogelwch.">
+<!ENTITY safeb.blocked.phishingPage.longDesc3 "<p>Mae gwefannau twyllodrus yn cael eu cynllunio i'ch twyllo i wneud rhywbeth peryglus, fel gosod meddalwedd, neu ddatgelu eich manylion personol, megis cyfrineiriau, rhifau ffôn neu gardiau credyd.</p><p>Gall gynnig unrhyw wybodaeth ar y dudalen we hon arwain at ddwyn eich manylion personol neu ryw dwyllo arall.</p>">
+
+<!ENTITY safeb.blocked.unwantedPage.title "Gwefan Meddalwedd Digroeso Hysbys!">
+<!-- Localization note (safeb.blocked.unwanted.shortDesc) - Please don't translate the contents of the <span id="unwanted_sitename"/> tag.  It will be replaced at runtime with a domain name (e.g. www.badsite.com) -->
+<!ENTITY safeb.blocked.unwantedPage.shortDesc "Mae'r dudalen hon <span id='unwanted_sitename'/> wedi ei chofnodi i gynnwys meddalwedd digroeso ac mae wedi ei rhwystro yn seiliedig ar eich dewisiadau diogelwch.">
+<!ENTITY safeb.blocked.unwantedPage.longDesc "Mae tudalennau meddalwedd digroeso yn ceisio gosod meddalwedd sy'n dwyllodrus ac yn effeithio ar eich system mewn ffyrdd anisgwyl.">
+
+<!ENTITY safeb.blocked.harmfulPage.title "Gall fod y wefan o'ch blaen yn cynnwys drwgwar">
+<!ENTITY safeb.blocked.harmfulPage.shortDesc "Mae &brandShortName; wedi rhwystro'r dudalen hon gan y gall geisio gosod apiau peryglus sy'n dwyn neu ddileu eich manylion (e.e., lluniau, cyfrineiriau, negeseuon a chardiau credyd).">
\ No newline at end of file
diff --git a/l10n-cy/mobile/android/chrome/pippki.properties b/l10n-cy/mobile/android/chrome/pippki.properties
new file mode 100644
index 0000000000..ea12ac41f6
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/pippki.properties
@@ -0,0 +1,84 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+nssdialogs.ok.label=Iawn
+nssdialogs.cancel.label=Diddymu
+
+# These strings are stolen from security/manager/locales/en-US/chrome/pippki/pippki.dtd
+downloadCert.title=Llwytho Tystysgrifau i Lawr
+downloadCert.message1=Rydych wedi cael cais i ymddiried mewn Awdurdod Tystysgrifo (CA) newydd.
+downloadCert.viewCert.label=Golwg
+downloadCert.trustSSL=Ymddiried i adnabod gwefannau.
+downloadCert.trustEmail=Ymddiried i adnabod defnyddwyr e-bost.
+pkcs12.getpassword.title=Deialog Mynediad y Cyfrinair
+pkcs12.getpassword.message=Rhowch y cyfrinair ddefnyddiwyd i amgryptio'r ffeil tystysgrif wrth gefn.
+clientAuthAsk.title=Cais am Adnabod Defnyddiwr
+clientAuthAsk.message1=Mae'r wefan yn gofyn i chi ddweud pwy ydych gyda thystysgrif diogelwch:
+clientAuthAsk.message2=Dewiswch dystysgrif i'w chyflwyno fel adnabyddiaeth:
+clientAuthAsk.message3=Manylion y dystysgrif:
+clientAuthAsk.remember.label=Cofio'r penderfyniad
+# LOCALIZATION NOTE(clientAuthAsk.nickAndSerial): Represents a single cert when
+# the user is choosing from a list of certificates.
+# %1$S is the nickname of the cert.
+# %2$S is the serial number of the cert in AA:BB:CC hex format.
+clientAuthAsk.nickAndSerial=%1$S [%2$S]
+# LOCALIZATION NOTE(clientAuthAsk.hostnameAndPort):
+# %1$S is the hostname of the server.
+# %2$S is the port of the server.
+clientAuthAsk.hostnameAndPort=%1$S:%2$S
+# LOCALIZATION NOTE(clientAuthAsk.organization): %S is the Organization of the
+# server cert.
+clientAuthAsk.organization=Corff: "%S"
+# LOCALIZATION NOTE(clientAuthAsk.issuer): %S is the Organization of the
+# issuer cert of the server cert.
+clientAuthAsk.issuer=Cyhoeddwyd o Dan: "%S"
+# LOCALIZATION NOTE(clientAuthAsk.issuedTo): %1$S is the Distinguished Name of
+# the currently selected client cert, such as "CN=John Doe,OU=Example" (without
+# quotes).
+clientAuthAsk.issuedTo=Cyhoeddwyd i: %1$S
+# LOCALIZATION NOTE(clientAuthAsk.serial): %1$S is the serial number of the
+# selected cert in AA:BB:CC hex format.
+clientAuthAsk.serial=Rhif cyfresol: %1$S
+# LOCALIZATION NOTE(clientAuthAsk.validityPeriod):
+# %1$S is the already localized notBefore date of the selected cert.
+# %2$S is the already localized notAfter date of the selected cert.
+clientAuthAsk.validityPeriod=Yn ddilys o %1$S hyd %2$S
+# LOCALIZATION NOTE(clientAuthAsk.keyUsages): %1$S is a comma separated list of
+# already localized key usages the selected cert is valid for.
+clientAuthAsk.keyUsages=Prif Ddefnydd: %1$S
+# LOCALIZATION NOTE(clientAuthAsk.emailAddresses): %1$S is a comma separated
+# list of e-mail addresses the selected cert is valid for.
+clientAuthAsk.emailAddresses=Cyfeiriadau e-bost: %1$S
+# LOCALIZATION NOTE(clientAuthAsk.issuedBy): %1$S is the Distinguished Name of
+# the cert which issued the selected cert.
+clientAuthAsk.issuedBy=Cyhoeddwyd gan: %1$S
+# LOCALIZATION NOTE(clientAuthAsk.storedOn): %1$S is the name of the PKCS #11
+# token the selected cert is stored on.
+clientAuthAsk.storedOn=Storiwyd ar: %1$S
+clientAuthAsk.viewCert.label=Golwg
+
+certmgr.title=Manylion Tystysgrif
+# These strings are stolen from security/manager/locales/en-US/chrome/pippki/certManager.dtd
+certmgr.subjectinfo.label=Dynodwyd i
+certmgr.issuerinfo.label=Cyhoeddwyd gan
+certmgr.periodofvalidity.label=Cyfnod Dilysrwydd
+certmgr.fingerprints.label=Olion bysedd
+certdetail.cn=Enw Cyffredin (CN): %1$S
+certdetail.o=Corff (O): %1$S
+certdetail.ou=Uned Corff (OU): %1$S
+# LOCALIZATION NOTE(certdetail.serialnumber): %1$S is the serial number of the
+# cert being viewed in AA:BB:CC hex format.
+certdetail.serialnumber=Rhif Cyfresol: %1$S
+# LOCALIZATION NOTE(certdetail.sha256fingerprint): %1$S is the SHA-256
+# Fingerprint of the cert being viewed in AA:BB:CC hex format.
+certdetail.sha256fingerprint=Ôl bys SHA-256: %1$S
+# LOCALIZATION NOTE(certdetail.sha1fingerprint): %1$S is the SHA-1 Fingerprint
+# of the cert being viewed in AA:BB:CC hex format.
+certdetail.sha1fingerprint=Ôl bys SHA1: %1$S
+# LOCALIZATION NOTE(certdetail.notBefore): %1$S is the already localized
+# notBefore date of the cert being viewed.
+certdetail.notBefore=Yn Cychwyn Ar: %1$S
+# LOCALIZATION NOTE(certdetail.notAfter): %1$S is the already localized notAfter
+# date of the cert being viewed.
+certdetail.notAfter=Daw I Ben AR: %1$S
diff --git a/l10n-cy/mobile/android/chrome/sync.properties b/l10n-cy/mobile/android/chrome/sync.properties
new file mode 100644
index 0000000000..16e5cb5dcd
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/sync.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Mobile Sync
+
+# %S is the date and time at which the last sync successfully completed
+lastSync2.label=Cydweddiad diwethaf: %S
+
+# %S is the username logged in
+account.label=Cyfrif: %S
+
diff --git a/l10n-cy/mobile/android/chrome/webcompatReporter.properties b/l10n-cy/mobile/android/chrome/webcompatReporter.properties
new file mode 100644
index 0000000000..6a7eee0e6a
--- /dev/null
+++ b/l10n-cy/mobile/android/chrome/webcompatReporter.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (webcompat.menu.name): A "site issue" is a bug, display,
+# or functionality problem with a webpage in the browser.
+webcompat.menu.name=Adrodd ar fater gwefan
+
+# LOCALIZATION NOTE (webcompat.reportDesktopMode.message): A " site issue" is a
+# bug, display, or functionality problem with a webpage in the browser.
+webcompat.reportDesktopMode.message=Adrodd ar fater gwefan?
+webcompat.reportDesktopModeYes.label=Adrodd
diff --git a/l10n-cy/mobile/android/defines.inc b/l10n-cy/mobile/android/defines.inc
new file mode 100644
index 0000000000..adeee3f2e2
--- /dev/null
+++ b/l10n-cy/mobile/android/defines.inc
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+#filter emptyLines
+
+#define MOZ_LANGPACK_CREATOR mozilla.org
+
+# If non-English locales wish to credit multiple contributors, uncomment this
+
+# variable definition and use the format specified.
+
+#define MOZ_LANGPACK_CONTRIBUTORS <em:contributor>Rhoslyn Prys</em:contributor> <em:contributor>David Chan</em:contributor> <em:contributor>Dewi B. Jones</em:contributor>
+
+#unfilter emptyLines
diff --git a/l10n-cy/mobile/android/mobile-l10n.js b/l10n-cy/mobile/android/mobile-l10n.js
new file mode 100644
index 0000000000..b410ad9aef
--- /dev/null
+++ b/l10n-cy/mobile/android/mobile-l10n.js
@@ -0,0 +1,6 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#filter substitution
+
diff --git a/l10n-cy/mobile/chrome/region.properties b/l10n-cy/mobile/chrome/region.properties
new file mode 100644
index 0000000000..3cb0f00e3f
--- /dev/null
+++ b/l10n-cy/mobile/chrome/region.properties
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: REVIEW_REQUIRED
+# Please do not commit any changes to this file without a review from
+# the l10n-drivers team (this includes en-US). In order to get one,
+# please file a bug, add the "productization" keyword and CC l10n@mozilla.com.
+
+# increment this number when anything gets changed in the list below.  This will
+# cause Firefox to re-read these prefs and inject any new handlers into the
+# profile database.  Note that "new" is defined as "has a different URL"; this
+# means that it's not possible to update the name of existing handler, so
+# don't make any spelling errors here.
+gecko.handlerService.defaultHandlersVersion=3
+
+# The default set of protocol handlers for mailto:
+gecko.handlerService.schemes.mailto.0.name=Yahoo! Mail
+gecko.handlerService.schemes.mailto.0.uriTemplate=https://compose.mail.yahoo.com/?To=%s
+gecko.handlerService.schemes.mailto.1.name=Gmail
+gecko.handlerService.schemes.mailto.1.uriTemplate=https://mail.google.com/mail/?extsrc=mailto&url=%s
+
+# This is the default set of web based feed handlers shown in the reader
+# selection UI
+browser.contentHandlers.types.0.title=Netvibes
+browser.contentHandlers.types.0.uri=http://www.netvibes.com/subscribe.php?url=%s
+
diff --git a/l10n-cy/mobile/overrides/appstrings.properties b/l10n-cy/mobile/overrides/appstrings.properties
new file mode 100644
index 0000000000..4cee067821
--- /dev/null
+++ b/l10n-cy/mobile/overrides/appstrings.properties
@@ -0,0 +1,41 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# BEFORE EDITING THIS FILE, PLEASE NOTE:
+# These strings are only here to support shipping Fennec ESR.
+# They are unused in GeckoView, so please don't make any changes.
+
+malformedURI2=Nid yw'r URL yn ddilys ac nid oes modd ei lwytho.
+fileNotFound=Nid oes modd canfod ffeil %S.
+fileAccessDenied=Nid yw ffeil %S yn ddarllenadwy.
+dnsNotFound2=Nid yw Firefox yn gallu canfod y gweinydd yn %S.
+unknownProtocolFound=Nid yw Firefox yn gwybod sut i agor y cyfeiriad hwn gan nad yw un o'r protocolau (%S) wedi eu cysylltu ag unrhyw raglen neu nad yw'n cael ei ganiatáu yn y cyd-destun hwn.
+connectionFailure=Nid yw Firefox yn gallu cysylltu â'r gweinydd yn %S.
+netInterrupt=Cafodd cysylltiad â %S ei darfu wrth i'r dudalen lwytho.
+netTimeout=Mae'r gweinydd yn %S yn cymryd gormod o amser i ymateb.
+redirectLoop=Mae Firefox wedi canfod fod gweinydd yn ailgyfeirio'r cais am y cyfeiriad yma mewn ffordd na fydd yn cael ei gwblhau.
+## LOCALIZATION NOTE (confirmRepostPrompt): In this item, don't translate "%S"
+confirmRepostPrompt=I ddangos y dudalen hon, rhaid i %S anfon gwybodaeth fydd yn ailadrodd unrhyw weithred (megis chwilio neu gadarnhau gorchymyn) gafodd ei chyflawni ynghynt.
+resendButton.label=Ail anfon
+unknownSocketType=Nid yw Firefox yn gwybod sut i gyfathrebu gyda'r gweinydd.
+netReset=Cafodd y cysylltiad i'r gweinydd ei ailosod wrth i'r dudalen lwytho.
+notCached=Nid yw'r ddogfen ar gael bellach.
+netOffline=Mae Firefox yn y modd all-lein ar hyn o bryd ac yn methu pori.
+isprinting=Nid oes modd i'r ddogfen newid wrth Argraffu neu yn Rhagolwg Argraffu.
+deniedPortAccess=Mae'r cyfeiriad yn defnyddio porth rhwydwaith sy'n cael ei ddefnyddio fel arfer i ddibenion heblaw pori'r We. Mae Firefox wedi gwrthod y cais er eich lles.
+proxyResolveFailure=Mae Firefox wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy nad oes modd ei ganfod.
+proxyConnectFailure=Mae Firefox wedi ei ffurfweddu i ddefnyddio gweinydd dirprwy sy'n gwrthod cysylltiadau.
+contentEncodingError=Methu dangos y dudalen rydych yn ceisio ei darllen am ei bod yn defnyddio math annilys a heb ei gynnal o gywasgiad.
+unsafeContentType=Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am ei bod yn cynnwys math o ffeil gall fod nad yw'n ddiogel ei hagor. Cysylltwch â pherchennog y wefan i'w hysbysu o'r broblem.
+malwareBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+harmfulBlocked=Mae'r wefan %S wedi ei hysbysu fel gwefan ymosod ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+deceptiveBlocked=Mae'r wefan %S wedi ei chofnodi fel gwefan twyllodrus ac wedi cael ei rwystro yn seiliedig ar y dewisiadau diogelwch.
+unwantedBlocked=Mae gwefan %S wedi ei hysbysu fel un sy'n ryddhau meddalwedd digroeso ac wedi cael ei rwystro ar sail eich dewisiadau diogelwch.
+cspBlocked=Mae gan y dudalen bolisi diogelwch cynnwys sy'n ei hatal rhag cael ei lwytho yn y ffordd yma.
+corruptedContentErrorv2=Mae'r wefan %S wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
+remoteXUL=Mae'r dudalen hon yn defnyddio technoleg sydd ddim yn cael ei gynnal bellach gan Firefox.
+sslv3Used=Nid yw Firefox y gallu gwarantu diogelwch eich data ar %S gan ei fod yn defnyddio SSLv3, protocol diogelwch sydd wedi torri.
+weakCryptoUsed=Mae perchennog %S wedi ffurfweddu ei wefan yn anghywir. I rwystro eich manylion rhag cael eu dwyn, nid yw Firefox wedi cysylltu â'r wefan.
+inadequateSecurityError=Mae'r wefan wedi ceisio negydu lefel annigonol o ddiogelwch.
+networkProtocolError=Mae Firefox wedi profi trosedd protocol rhwydwaith nad oes modd ei drwsio.
diff --git a/l10n-cy/mobile/overrides/netError.dtd b/l10n-cy/mobile/overrides/netError.dtd
new file mode 100644
index 0000000000..9b9ab205e2
--- /dev/null
+++ b/l10n-cy/mobile/overrides/netError.dtd
@@ -0,0 +1,121 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">
+%brandDTD;
+
+<!ENTITY loadError.label "Anhawster llwytho tudalen">
+<!ENTITY retry.label "Ceisiwch Eto">
+
+<!-- Specific error messages -->
+
+<!ENTITY connectionFailure.title "Methu cysylltu">
+<!ENTITY connectionFailure.longDesc2 "&sharedLongDesc3;">
+
+<!ENTITY deniedPortAccess.title "Mae'r cyfeiriad wedi ei gyfyngu">
+<!ENTITY deniedPortAccess.longDesc "">
+
+<!ENTITY dnsNotFound.title "Heb ganfod gweinydd">
+<!-- LOCALIZATION NOTE (dnsNotFound.longDesc4) This string contains markup including widgets for searching
+     or enabling wifi connections. The text inside tags should be localized.  Do not change the ids. -->
+<!ENTITY dnsNotFound.longDesc4 "<ul> <li>Gwiriwch y cyfeiriad am wallau teipio, megis <strong>ww</strong>.example.com yn lle <strong>www</strong>.example.com</li> <div id='searchbox'> <input id='searchtext' type='search'></input> <button id='searchbutton'>Chwilio</button> </div> <li>Os nad oeddech yn gallu llwytho unrhyw dudalennau, gwiriwch ddata eich dyfais neu'r cysylltiad diwifr. <button id='wifi'>Galluogi'r Diwifr</button> </li> </ul>">
+
+<!ENTITY fileNotFound.title "Heb ganfod ffeil">
+<!ENTITY fileNotFound.longDesc "<ul> <li>Gwiriwch yr enw ffeil am brif lythrennu neu wallau teipio eraill.</li> <li>Gwiriwch i weld os yw'r ffeil wedi symud, ailenwi neu ei dileu.</li> </ul>">
+
+<!ENTITY fileAccessDenied.title "Mae mynediad i'r ffeil wedi ei wrthod">
+<!ENTITY fileAccessDenied.longDesc "<ul> <li>Gall ei fod wedi ei dynnu, symud neu fod caniatâd ffeiliau yn rhwystro mynediad.</li> </ul>">
+
+<!ENTITY generic.title "Wps.">
+<!ENTITY generic.longDesc "<p>Nid yw &brandShortName; yn gallu llwytho'r dudalen am ryw reswm.</p>">
+
+<!ENTITY malformedURI.title "Nid yw'r cyfeiriad yn ddilys">
+<!-- LOCALIZATION NOTE (malformedURI.longDesc2) This string contains markup including widgets for searching
+     or enabling wifi connections. The text inside the tags should be localized. Do not touch the ids. -->
+<!ENTITY malformedURI.longDesc2 "<ul> <li>Mae cyfeiriadau gwe fel arfer wedi eu hysgrifennu fel <strong>http://www.example.com/</strong></li> <div id='searchbox'> <input id='searchtext' type='search'></input> <button id='searchbutton'>Search</button> </div> <li>Gwnewch yn siŵr eich bod yn defnyddio blaen slaes (h.y. <strong>/</strong>).</li> </ul>">
+
+<!ENTITY netInterrupt.title "Cafodd y cysylltiad ei darfu">
+<!ENTITY netInterrupt.longDesc2 "&sharedLongDesc3;">
+
+<!ENTITY notCached.title "Daeth y Ddogfen i Ben">
+<!ENTITY notCached.longDesc "<p>Nid yw'r ddogfen gofynnwyd amdani ar gael yn storfa &brandShortName;.</p><ul><li>Fel cam i sicrhau diogelwch nid yw &brandShortName; yn gofyn eto am ddogfennau sensitif.</li><li>Cliciwch Ceisio Eto i ofyn eto am y ddogfen o'r wefan.</li></ul>">
+
+<!ENTITY netOffline.title "Modd all-lein">
+
+<!ENTITY contentEncodingError.title "Gwall Amgodio Cynnwys">
+<!ENTITY contentEncodingError.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY unsafeContentType.title "Math Anniogel o Ffeil">
+<!ENTITY unsafeContentType.longDesc "<ul> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY netReset.title "Cafodd y cysylltiad ei ailosod">
+<!ENTITY netReset.longDesc2 "&sharedLongDesc3;">
+
+<!ENTITY netTimeout.title "Mae'r cyfnod cyswllt wedi dod i ben">
+<!ENTITY netTimeout.longDesc2 "&sharedLongDesc3;">
+
+<!ENTITY unknownProtocolFound.title "Heb ddeall y cyfeiriad">
+<!ENTITY unknownProtocolFound.longDesc "<ul> <li>Efallai bydd angen i chi osod meddalwedd arall i agor y cyfeiriad yma.</li> </ul>">
+
+<!ENTITY proxyConnectFailure.title "Mae'r gweinydd dirprwy yn gwrthod cysylltiadau">
+<!ENTITY proxyConnectFailure.longDesc "<ul> <li>Gwiriwch osodiadau'r dirprwy i wneud yn siŵr eu bod yn gywir.</li> <li>Cysylltwch â'ch gweinyddwr system i wneud yn siŵr fod y gweinydd dirprwyol yn gweithio.</li> </ul>">
+
+<!ENTITY proxyResolveFailure.title "Methu canfod y gweinydd dirprwyol">
+<!-- LOCALIZATION NOTE (proxyResolveFailure.longDesc3) This string contains markup including widgets for enabling wifi connections.
+     The text inside the tags should be localized. Do not touch the ids. -->
+<!ENTITY proxyResolveFailure.longDesc3 "<ul> <li>Gwiriwch eich gosodiadau dirprwy i sicrhau eu bod yn gywir.</li> <li>Gwiriwch i sicrhau fod gennych gysylltiad data a Wi-Fi sy'n gweithio. <button id='wifi'>Galluogi Diwifr</button> </li> </ul>">
+
+<!ENTITY redirectLoop.title "Nid yw'r dudalen yn ailgyfeirio'n iawn">
+<!ENTITY redirectLoop.longDesc "<ul> <li>Gall y broblem yma fod wedi ei hachosi drwy analluogi neu wrthod cwci.</li> </ul>">
+
+<!ENTITY unknownSocketType.title "Ymateb annisgwyl gan y gweinydd">
+<!ENTITY unknownSocketType.longDesc "<ul> <li>Gwiriwch fod gan eich system Reolwr Diogelwch Personol wedi ei osod.</li> <li>Gall hyn fod oherwydd ffurfweddiad ansafonol ar y gweinydd.</li> </ul>">
+
+<!ENTITY nssFailure2.title "Methodd y Cysylltiad Diogel">
+<!ENTITY nssFailure2.longDesc2 "<ul> <li>Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am nad oes modd dilysu'r data rydych wedi ei dderbyn.</li> <li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li> </ul>">
+
+<!ENTITY nssBadCert.title "Methodd y Cysylltiad Diogel">
+<!ENTITY nssBadCert.longDesc2 "<ul> <li>Gall hwn fod yn anhawster gyda ffurfweddiad y gweinydd neu gall fod yn rhywun sy'n ceisio dynwared y gweinydd.</li> <li>Os ydych wedi cysylltu'n llwyddiannus gyda'r gweinydd yn y gorffennol, efallai mai gwall dros dro ydyw ac i geisio eto.</li> </ul>">
+
+<!-- LOCALIZATION NOTE (sharedLongDesc3) This string contains markup including widgets for enabling wifi connections.
+     The text inside the tags should be localized. Do not touch the ids. -->
+<!ENTITY sharedLongDesc3 "<ul> <li>Mae'n bosib fod y wefan yn brysur neu ddim ar gael. Ceisiwch eto cyn bo hir.</li> <li>Os nad oes modd i chi lwytho unrhyw dudalennau, gwiriwch gysylltiad data neu ddiwifr eich dyfais symudol. <button id='wifi'>Galluogi Diwifr</button> </li> </ul>">
+
+<!ENTITY cspBlocked.title "Rhwystrwyd gan Bolisi Diogelwch Cynnwys">
+<!ENTITY cspBlocked.longDesc "<p>Mae &brandShortName; wedi rhwystro'r dudalen rhag llwytho yn y ffordd yma gan fod gan y dudalen bolisi diogelwch cynnwys sy'n atal hynny.</p>">
+
+<!ENTITY corruptedContentErrorv2.title "Gwall Cynnwys Llygredig">
+<!ENTITY corruptedContentErrorv2.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio ei gweld yn sgil canfod gwall trosglwyddo data.</p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.</li></ul>">
+
+<!ENTITY securityOverride.linkText "Neu mae modd ychwanegu eithriad…">
+<!ENTITY securityOverride.getMeOutOfHereButton "Allan o fan hyn!">
+<!ENTITY securityOverride.exceptionButtonLabel "Ychwanegu Eithriad…">
+
+<!-- LOCALIZATION NOTE (securityOverride.warningContent) - Do not translate the
+contents of the <xul:button> tags.  The only language content is the label= field,
+which uses strings already defined above. The button is included here (instead of
+netError.xhtml) because it exposes functionality specific to firefox. -->
+
+<!ENTITY securityOverride.warningContent "<p>Ni ddylech ychwanegu eithriad os ydych yn defnyddio cyswllt gwe nad ydych yn ymddiried ynddo'n llwyr neu os nad ydych wedi arfer a gweld rhybudd ar y gweinydd hwn.</p>  <button id='getMeOutOfHereButton'>&securityOverride.getMeOutOfHereButton;</button> <button id='exceptionDialogButton'>&securityOverride.exceptionButtonLabel;</button>">
+
+<!ENTITY remoteXUL.title "XUL pell">
+<!ENTITY remoteXUL.longDesc "<p><ul><li>Cysylltwch â pherchnogion y wefan i'w hysbysu am y broblem..</li></ul></p>">
+
+<!ENTITY sslv3Used.title "Methu Cysylltu'n Ddiogel">
+<!-- LOCALIZATION NOTE (sslv3Used.longDesc) - Do not translate
+     "SSL_ERROR_UNSUPPORTED_VERSION". -->
+<!ENTITY sslv3Used.longDesc "Gwybodaeth uwch: SSL_ERROR_UNSUPPORTED_VERSION">
+
+<!ENTITY weakCryptoUsed.title "Nid yw eich cysylltiad yn ddiogel">
+<!-- LOCALIZATION NOTE (weakCryptoUsed.longDesc) - Do not translate
+     "SSL_ERROR_NO_CYPHER_OVERLAP". -->
+<!ENTITY weakCryptoUsed.longDesc "Gwybodaeth uwch: SSL_ERROR_NO_CYPHER_OVERLAP">
+
+<!ENTITY inadequateSecurityError.title "Nid yw eich cysylltiad yn ddiogel">
+<!-- LOCALIZATION NOTE (inadequateSecurityError.longDesc) - Do not translate
+     "NS_ERROR_NET_INADEQUATE_SECURITY". -->
+<!ENTITY inadequateSecurityError.longDesc "Mae <p><span class='hostname'></span> yn defnyddio technoleg diogelwch sy'n hen ac yn agored i ymosodiad. Gall yr ymosodwr weld manylion am hyn roeddech yn meddwl ei fod yn ddiogel. Mae angen i weinyddwr y wefan drwsio'r gweinydd yn gyntaf cyn bod modd i chi ymweld â' r wefan.</p><p>Cod gwall: NS_ERROR_NET_INADEQUATE_SECURITY</p>">
+
+<!ENTITY networkProtocolError.title "Gwall Protocol Rhwydwaith">
+<!ENTITY networkProtocolError.longDesc "<p>Nid oes modd dangos y dudalen rydych yn ceisio'i gweld oherwydd canfuwyd gwall yn y protocol rhwydwaith.</p><ul><li>Cysylltwch â pherchenogion y wefan i roi gwybod iddynt am y broblem hon.</li></ul>">
diff --git a/l10n-cy/netwerk/necko.properties b/l10n-cy/netwerk/necko.properties
new file mode 100644
index 0000000000..16af2e0bd8
--- /dev/null
+++ b/l10n-cy/netwerk/necko.properties
@@ -0,0 +1,109 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ResolvingHost=Looking up
+#ConnectedTo=Connected to 
+#ConnectingTo=Connecting to 
+#SendingRequestTo=Sending request to 
+#TransferringDataFrom=Transferring data from 
+
+3=Chwilio %1$S…
+4=Cysylltwyd â %1$S…
+5=Anfon cais at %1$S…
+6=Trosglwyddo data o %1$S…
+7=Cysylltu â %1$S…
+8=Darllen %1$S\u0020 
+9=Ysgrifennwyd %1$S
+10=Aros am %1$S…
+11=Wedi chwilio am %1$S…
+12=Cyflawni ysgwyd llaw TLS i %1$S…
+13=Mae'r TLS ysgwyd llaw wedi gorffen ar gyfer %1$S…
+
+27=Cychwyn trosglwyddiad FTP…
+28=Gorffen cyfnewidiad FTP
+
+RepostFormData=Mae'r dudalen gwe'n cael ei hailgyfeirio i leoliad newydd. Hoffech chi ail anfon y ffurflen data rydych wedi ei deipio i'r lleoliad newydd?
+
+# Directory listing strings
+DirTitle=Mynegai %1$S
+DirGoUp=I fyny i gyfeiriadur uwch
+ShowHidden=Dangos gwrthrychau cudd
+DirColName=Enw
+DirColSize=Maint
+DirColMTime=Newidiwyd Diwethaf
+DirFileLabel=Ffeil:\u0020 
+
+SuperfluousAuth=Rydych ar fin mewngofnodi i wefan "%1$S" gydag enw defnyddiwr "%2$S", ond nid yw'r wefan angen dilysiad. Gall hyn fod yn ymgais i'ch twyllo.\n\nAi "%1$S" yw'r wefan rydych am ymweld â hi?
+AutomaticAuth=Rydych ar fin mewngofnodi i wefan "%1$S" gydag enw defnyddiwr "%2$S".
+
+TrackerUriBlocked=Cafod yr adnodd yn “%1$S” ei rwystro gan fod rhwystro cynnwys wedi ei alluogi.
+UnsafeUriBlocked=Mae'r adnodd yn “%1$S” wedi ei rwystro gan Pori Diogel.
+CookieBlockedByPermission=Cafodd gais i gael mynediad at gwcis neu storfa ar “%1$S” ei wrthod oherwydd caniatâd cwcis cyfaddas.
+CookieBlockedTracker=Cafodd gais i gael mynediad at gwcis neu storfa ar “%1$S” ei rwystro oherwydd iddo ddod gan draciwr ac mae rhwystro cynnwys wedi ei alluogi.
+CookieBlockedAll=Cafodd gais i gael mynediad at gwcis neu storfa ar “%1$S” ei rwystro oherwydd ein bod yn rhwystro pob cais mynediad i storfa.
+CookieBlockedForeign=Cafodd gais i gael mynediad at gwcis neu storfa ar “%1$S” ei rwystro oherwydd ein bod yn rhwystro pob cais trydydd parti mynediad i storfa ac mae rhwystro cynnwys wedi ei alluogi.
+
+# As part of dynamic first-party isolation, third-party resources might be limited to "partitioned" storage access that is separate from the first-party context.
+# This allows e.g. cookies to still be set, and prevents tracking without totally blocking storage access. This message is shown in the web console when this happens
+# to inform developers that their storage is isolated.
+CookiePartitionedForeign=Darparwyd mynediad cwci neu storio rhanedig i “%1$S”  gan ei fod yn cael ei lwytho yng nghyd-destun trydydd parti ac mae'r rhaniad storio wedi'i alluogi.
+
+# LOCALIZATION NOTE (CookieAllowedForOriginByStorageAccessAPI): %2$S and %1$S are URLs.
+CookieAllowedForOriginByStorageAccessAPI=Mynediad storio a roddwyd ar gyfer ffynhonnell “%2$S”  ar “%1$S”.
+# LOCALIZATION NOTE (CookieAllowedForOriginByHeuristic): %2$S and %1$S are URLs.
+CookieAllowedForOriginByHeuristic=Mynediad storio a roddir yn awtomatig ar gyfer ffynhonnell “%2$S” ar “%1$S”.
+# LOCALIZATION NOTE (CookieAllowedForFpiByHeuristic): %2$S and %1$S are URLs.
+CookieAllowedForFpiByHeuristic=Mae mynediad storio yn cael ei roi'n awtomatig ar gyfer ynysu Parti Cyntaf “%2$S” ar “%1$S”.
+
+# LOCALIZATION NOTE(CookieRejectedNonRequiresSecure): %1$S is the cookie name. Do not localize "sameSite=none" and "secure".
+CookieRejectedNonRequiresSecure=Gwrthodwyd cwci “%1$S” oherwydd bod ganddo'r priodoledd “sameSite=none” ond ei fod yn colli'r priodoledd “secure”.
+# LOCALIZATION NOTE(CookieRejectedNonRequiresSecureForBeta): %1$S is the cookie name. %2$S is a URL. Do not localize "sameSite", "sameSite=none" and "secure".
+CookieRejectedNonRequiresSecureForBeta=Bydd cwci “%1$S” yn cael ei wrthod yn fuan oherwydd bod ganddo'r priodoledd “sameSite” wedi'i osod i “none” neu werth annilys, heb y priodoledd “secure”. I wybod mwy am y priodoledd “sameSite”, darllenwch %2$S.
+# LOCALIZATION NOTE(CookieLaxForced): %1$S is the cookie name. Do not localize "sameSite", "lax" and "sameSite=lax".
+CookieLaxForced=Mae gan gwci “%1$S” bolisi “sameSite” wedi'i osod i “lax” oherwydd ei fod yn colli priodoledd “sameSite”, a “sameSite=lax” yw'r gwerth ragosodedig ar gyfer y briodoledd hon.
+# LOCALIZATION NOTE(CookieLaxForcedForBeta): %1$S is the cookie name. %2$S is a URL. Do not localize "sameSite", "lax" and "sameSite=lax", "sameSite=none".
+CookieLaxForcedForBeta=Nid oes gan gwci “%1$S” werth priodoledd “sameSite” iawn. Cyn bo hir, bydd cwcis heb y priodoledd “sameSite” neu sydd â gwerth annilys yn cael eu trin fel “lax”. Mae hyn yn golygu na fydd y cwci yn cael ei anfon mwyach mewn cyd-destunau trydydd parti. Os yw'ch cais yn dibynnu i'r cwci hwn fod ar gael mewn cyd-destunau o'r fath, ychwanegwch y priodoledd “sameSite=none” iddo. I wybod mwy am y priodoledd “sameSite”, darllenwch %2$S.
+# LOCALIZATION NOTE: %1$S is cookie name. Do not localize "sameSite", "lax", "strict" and "none"
+CookieSameSiteValueInvalid=Gwerth annilys “sameSite” cwci “%1$S”. Y gwerthoedd a gefnogir yw: “lax”, “sctrict”, “none”.
+
+# LOCALIZATION NOTE(CookieRejectedNonRequiresSecure2): %1$S is the cookie name. Do not localize "SameSite=None" and "secure".
+CookieRejectedNonRequiresSecure2=Gwrthodwyd cwci “%1$S” oherwydd bod ganddo'r priodoledd “sameSite=None” ond fod y priodoledd “secure” ar goll.
+# LOCALIZATION NOTE(CookieRejectedNonRequiresSecureForBeta2): %1$S is the cookie name. %2$S is a URL. Do not localize "SameSite", "SameSite=None" and "secure".
+CookieRejectedNonRequiresSecureForBeta2=Bydd cwci “%1$S” yn cael ei wrthod yn fuan oherwydd bod ganddo'r priodoledd “sameSite” wedi'i osod i “None” neu werth annilys, heb y priodoledd “secure”. I wybod mwy am y priodoledd “sameSite”, darllenwch %2$S.
+# LOCALIZATION NOTE(CookieLaxForced2): %1$S is the cookie name. Do not localize "SameSite", "Lax" and "SameSite=Lax".
+CookieLaxForced2=Mae gan gwci “%1$S” bolisi “sameSite” wedi'i osod i “Lax” oherwydd ei fod yn colli priodoledd “sameSite”, a “sameSite=Lax” yw'r gwerth ragosodedig ar gyfer y briodoledd hon.
+# LOCALIZATION NOTE(CookieLaxForcedForBeta2): %1$S is the cookie name. %2$S is a URL. Do not localize "SameSite", "Lax" and "SameSite=Lax", "SameSite=None".
+CookieLaxForcedForBeta2=Nid oes gan gwci “%1$S” werth priodoledd “SameSite” iawn. Cyn bo hir, bydd cwcis heb y priodoledd “SameSite” neu sydd â gwerth annilys yn cael eu trin fel “Lax”. Mae hyn yn golygu na fydd y cwci yn cael ei anfon mwyach mewn cyd-destunau trydydd parti. Os yw'ch cais yn dibynnu i'r cwci hwn fod ar gael mewn cyd-destunau o'r fath, ychwanegwch y priodoledd “SameSite=None” iddo. I wybod mwy am y priodoledd “SameSite”, darllenwch %2$S.
+# LOCALIZATION NOTE(CookieSameSiteValueInvalid2): %1$S is cookie name. Do not localize "SameSite", "Lax", "Strict" and "None"
+CookieSameSiteValueInvalid2=Gwerth annilys “SameSite” cwci “%1$S”. Y gwerthoedd a gefnogir yw: “Lax”, “Strict”, “None”.
+# LOCALIZATION NOTE (CookieOversize): %1$S is the cookie name. %2$S is the number of bytes. "B" means bytes.
+CookieOversize=Mae cwci “%1$S” yn annilys oherwydd bod ei faint yn rhy fawr. Y maint mwyaf yw %2$S B.
+# LOCALIZATION NOTE (CookiePathOversize): %1$S is the cookie name. %2$S is the number of bytes. "B" means bytes.
+CookiePathOversize=Mae cwci “%1$S” yn annilys oherwydd bod maint ei lwybr yn rhy fawr. Y maint mwyaf yw %2$S B.
+# LOCALIZATION NOTE (CookieSchemefulRejectForBeta): %1$S is the cookie name. %2$S is the hostname.
+CookieSchemefulRejectForBeta=Cyn bo hir, bydd cwci “%1$S” yn cael ei drin fel cwci traws-safle yn erbyn “%2$S” oherwydd nad yw'r cynllun yn cyfateb.
+# LOCALIZATION NOTE (CookieSchemefulReject): %1$S is the cookie name. %2$S is the hostname.
+CookieSchemefulReject=Mae cwci “%1$S” wedi cael ei drin fel traws-safle yn erbyn “%2$S” oherwydd nad yw’r cynllun yn cyfateb.
+# LOCALIZATION NOTE (CookieRejectedByPermissionManager): %1$S is the cookie response header.
+CookieRejectedByPermissionManager=Mae cwci “%1$S” wedi ei wrthod gan ganiatâd gosodedig y defnyddiwr.
+# LOCALIZATION NOTE (CookieRejectedInvalidCharName): %1$S is the cookie name.
+CookieRejectedInvalidCharName=Mae cwci “%1$S” wedi’i wrthod oherwydd nodau annilys yn yr enw.
+# LOCALIZATION NOTE (CookieRejectedInvalidDomain): %1$S is the cookie name.
+CookieRejectedInvalidDomain=Mae cwci “%1$S” wedi’i wrthod oherwydd parth annilys.
+# LOCALIZATION NOTE (CookieRejectedInvalidPrefix): %1$S is the cookie name.
+CookieRejectedInvalidPrefix=Mae cwci “%1$S” wedi’i wrthod oherwydd rhagddodiad annilys.
+# LOCALIZATION NOTE (CookieRejectedInvalidCharValue): %1$S is the cookie name.
+CookieRejectedInvalidCharValue=Mae cwci “%1$S” wedi’i wrthod oherwydd nodau annilys yn y gwerth.
+# LOCALIZATION NOTE (CookieRejectedHttpOnlyButFromScript): %1$S is the cookie name.
+CookieRejectedHttpOnlyButFromScript=Mae cwci “%1$S” wedi’i wrthod oherwydd bod eisoes cwci HTTPS-Only ond fod sgript wedi ceisio cadw un.
+# LOCALIZATION NOTE (CookieRejectedSecureButHttp): %1$S is the cookie name.
+CookieRejectedSecureButNonHttps=Mae cwci “%1$S” wedi’i wrthod oherwydd nad oes modd gosod cwci nad yw'n HTTPS fel “secure”.
+# LOCALIZATION NOTE (CookieRejectedThirdParty): %1$S is the cookie response header.
+CookieRejectedThirdParty=Mae cwci “%1$S” wedi’i wrthod oherwydd ei fod yn drydydd parti.
+# LOCALIZATION NOTE (CookieRejectedNonsecureOverSecure): %1$S is the cookie name.
+CookieRejectedNonsecureOverSecure=Mae cwci “%1$S” wedi’i wrthod oherwydd fod yna eisoes gwci “secure”.
+# LOCALIZATION NOTE (CookieRejectedExpired): %1$S is the cookie name.
+CookieRejectedExpired=Mae cwci “%1$S” wedi’i wrthod am ei fod eisoes wedi dod i ben.
+# LOCALIZATION NOTE (CookieRejectedForNonSameSiteness): %1$S is the cookie name.
+CookieRejectedForNonSameSiteness=Gwrthodwyd cwci “%1$S” oherwydd ei fod mewn cyd-destun traws-safle a’i “SameSite” yw “Lax” neu “Strict”.
diff --git a/l10n-cy/security/manager/chrome/pipnss/nsserrors.properties b/l10n-cy/security/manager/chrome/pipnss/nsserrors.properties
new file mode 100644
index 0000000000..1d2b8cf7ce
--- /dev/null
+++ b/l10n-cy/security/manager/chrome/pipnss/nsserrors.properties
@@ -0,0 +1,331 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+SSL_ERROR_EXPORT_ONLY_SERVER=Methu cyfathrebu'n ddiogel. Nid yw'r cyfoed cyn cynnal amgryptiad lefel uchel.
+SSL_ERROR_US_ONLY_SERVER=Methu cyfathrebu'n ddiogel. Mae'r cyfoed angen amgryptiad lefel uchel nad yw'n cael ei gynnal.
+SSL_ERROR_NO_CYPHER_OVERLAP=Methu cyfathrebu'n ddiogel gyda cyfoed: dim algorithm(au) amgrypriad cyffredin.
+SSL_ERROR_NO_CERTIFICATE=Methu canfod tystysgrif neu allwedd angenrheidiol ar gyfer dilysu.
+SSL_ERROR_BAD_CERTIFICATE=Methu cyfathrebu'n ddiogel gyda'r cyfoed: tystysgrif y cyfoed wedi ei wrthod.
+SSL_ERROR_BAD_CLIENT=Mae'r gweinydd wedi derbyn data gwael gan y cleient.
+SSL_ERROR_BAD_SERVER=Mae'r cleient wedi derbyn data gwael gan y gweinydd.
+SSL_ERROR_UNSUPPORTED_CERTIFICATE_TYPE=Maeth o dystysgrif sydd heb ei gynnal.
+SSL_ERROR_UNSUPPORTED_VERSION=Mae'r cyfoed yn defnyddio math o brotocol diogel nad yw'n cael ei gynnal.
+SSL_ERROR_WRONG_CERTIFICATE=Methodd dilysu'r cleient: nid yw allwedd breifat yng nghronfa ddata allweddi yn cydfynd â'r allwedd gyhoeddus yng gntonfa ddata'r tystysgrifau.
+SSL_ERROR_BAD_CERT_DOMAIN=Methu cyfathrebu'n ddiogel gyda'r cyfoed; nid yw'r enw parth yn cydfynd â thystysgrif y gweinydd.
+SSL_ERROR_POST_WARNING=Cod gwall SSL heb ei adnabod.
+SSL_ERROR_SSL2_DISABLED=Dim ond SSL fersiwn 2 mae'r cyfoed yn ei gynnal ac mae wedi ei analluogi'n lleol.
+SSL_ERROR_BAD_MAC_READ=Derbyniodd SSL gofnod gyda Chod Dilysu Neges anghywir.
+SSL_ERROR_BAD_MAC_ALERT=Mae cyfoed SSL yn cofnodi Cod Dilysu Neges anghywir.
+SSL_ERROR_BAD_CERT_ALERT=Nid yw cyfode SSL: yn gallu dilysu eich tystysgrif.
+SSL_ERROR_REVOKED_CERT_ALERT=Mae'r cyfoed SSL wedi gwrthod eich tystysgrif fel un wedi ei atal.
+SSL_ERROR_EXPIRED_CERT_ALERT=Mae'r cyfoed SSL wedi gwrthod eich tystysgrif fel un wedi dod i ben.
+SSL_ERROR_SSL_DISABLED=Methu cysylltu: SSL wedi ei analluogi.
+SSL_ERROR_FORTEZZA_PQG=Methu cysylltu: cyfoed SSL mewn parth FORTEZZA arall.
+SSL_ERROR_UNKNOWN_CIPHER_SUITE=Mae cais wedi ei dderbyn am swit seiffr SSL.
+SSL_ERROR_NO_CIPHERS_SUPPORTED=Nid oes swit seiffr ar gael ac wedi eu galluogi yn y rhaglen hon.
+SSL_ERROR_BAD_BLOCK_PADDING=Mae SSL wedi derbyn cofnod gyda phadin bloc gwael.
+SSL_ERROR_RX_RECORD_TOO_LONG=Mae SSL wedi derbyn cofnod sy'n hirach na'r hyd posib.
+SSL_ERROR_TX_RECORD_TOO_LONG=Mae SSL wedi ceisio anfon cofnod sy'n fwy na'r hyd posib.
+SSL_ERROR_RX_MALFORMED_HELLO_REQUEST=Mae SSL wedi derbyn neges ysgwyd llaw Cais Helo anffurf.
+SSL_ERROR_RX_MALFORMED_CLIENT_HELLO=Mae SSL wedi derbyn neges ysgwyd llaw Helo Cleient anffurf.
+SSL_ERROR_RX_MALFORMED_SERVER_HELLO=Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd anffurf.
+SSL_ERROR_RX_MALFORMED_CERTIFICATE=Mae SSL wedi derbyn neges ysgwyd llaw Tystysgrif anffurf.
+SSL_ERROR_RX_MALFORMED_SERVER_KEY_EXCH=Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Gweinydd anffurf.
+SSL_ERROR_RX_MALFORMED_CERT_REQUEST=Derbyniodd SSL neges ysgwyd llaw Cais Tystysgrif anffurfedig.
+SSL_ERROR_RX_MALFORMED_HELLO_DONE=Derbyniodd SSL neges ysgwyd llaw Server Hello Done anffurfedig.
+SSL_ERROR_RX_MALFORMED_CERT_VERIFY=Mae SSL wedi derbyn neges ysgwyd llaw Dilysu Tystysgrif anffurf.
+SSL_ERROR_RX_MALFORMED_CLIENT_KEY_EXCH=Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Cleient anffurf.
+SSL_ERROR_RX_MALFORMED_FINISHED=Mae SSL wedi derbyn neges ysgwyd llaw Terfynnwyd annfurf.
+SSL_ERROR_RX_MALFORMED_CHANGE_CIPHER=Mae SSL wedi derbyn cofnod Manyleb Seiffr Newid anffurf.
+SSL_ERROR_RX_MALFORMED_ALERT=Mae SSL wedi derbyn cofnod Rhybudd anffurf.
+SSL_ERROR_RX_MALFORMED_HANDSHAKE=Mae SSL wedi derbyn cofnod Ysgwyd Llaw anffurf.
+SSL_ERROR_RX_MALFORMED_APPLICATION_DATA=Mae SSL wedi derbyn cofnod Data Rhaglen Anffurf.
+SSL_ERROR_RX_UNEXPECTED_HELLO_REQUEST=Mae SSL wedi derbyn neges ysgwyd llaw Cais Helo annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CLIENT_HELLO=Mae SSL wedi derbyn neges ysgwyd llaw Helo Cleient annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_SERVER_HELLO=Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CERTIFICATE=Mae SSL wedi derbyn neges ysgwyd llaw Tystysgrif annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_SERVER_KEY_EXCH=Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Gweinydd annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CERT_REQUEST=Mae SSL wedi derbyn neges ysgwyd llaw Cais Tystysgrif annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_HELLO_DONE=Mae SSL wedi derbyn neges ysgwyd llaw Helo Gweinydd Cwblhawyd annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CERT_VERIFY=Mae SSL wedi derbyn neges ysgwyd llaw Dilysu Tystysgrif annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CLIENT_KEY_EXCH=Mae SSL wedi derbyn neges ysgwyd llaw Cyfnewid Allwedd Cleient annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_FINISHED=Mae SSL wedi derbyn neges ysgwyd llaw Terfynnu annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_CHANGE_CIPHER=Mae SSL wedi derbyn cofnod Manyleb Seiffr Newid annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_ALERT=Mae SSL wedi derbyn cofnod Rhybudd annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_HANDSHAKE=Mae SSL wedi derbyn cofnod Ysgwyd Llaw annisgwyl.
+SSL_ERROR_RX_UNEXPECTED_APPLICATION_DATA=Mae SSL wedi derbyn cofnod Data Rhaglen annisgwyl.
+SSL_ERROR_RX_UNKNOWN_RECORD_TYPE=Mae SSL wedi derbyn cofnod gyda math data anhysbys.
+SSL_ERROR_RX_UNKNOWN_HANDSHAKE=Mae SSL wedi derbyn negws ysgwyd llaw gyda math data anhysbys.
+SSL_ERROR_RX_UNKNOWN_ALERT=Mae SSL wedi derbyn cofnod rhybudd gyda math disgrifiad anhysbys.
+SSL_ERROR_CLOSE_NOTIFY_ALERT=Mae cyfoed SSL wedi cau'r cysylltiad.
+SSL_ERROR_HANDSHAKE_UNEXPECTED_ALERT=Nid oess y cyfoed SSL yn disgwyl y negws ysgwyd llaw dderbyniodd.
+SSL_ERROR_DECOMPRESSION_FAILURE_ALERT=Nid oess y cyfoed SSL yn gallu datgywasgu'r cofnod SSL y derbyniodd yn llwyddiannus.
+SSL_ERROR_HANDSHAKE_FAILURE_ALERT=Nid oedd cyfoed SSL yn gallu negydu set dderbyniol o baramedrau diogelwch.
+SSL_ERROR_ILLEGAL_PARAMETER_ALERT=Gwrthododd cyfoed SSL neges ysgwyd llaw oherwydd cynnwys annerbyniol.
+SSL_ERROR_UNSUPPORTED_CERT_ALERT=Nid yw cyfoed SSL yn cynnal tystysgrifau o'r matha mae wedi eu derbyn.
+SSL_ERROR_CERTIFICATE_UNKNOWN_ALERT=Mae gan gyfoed SSL anhawster amhenodol gyda'r dystysgrif mae wedi ei derbyn.
+SSL_ERROR_GENERATE_RANDOM_FAILURE=Profodd SSL fethiant a'o gynhyrchydd rhifau hap.
+SSL_ERROR_SIGN_HASHES_FAILURE=Methu llofnodi data digidol angenrheidiol ar gyfer dilysu eich tystysgrif.
+SSL_ERROR_EXTRACT_PUBLIC_KEY_FAILURE=Roedd SSL yn methu tynnu'r allwedd gyhoeddus o dystysgrif y cyfoed.
+SSL_ERROR_SERVER_KEY_EXCHANGE_FAILURE=Bu methiant amhenodol wrth brosesu ysgwyd llaw Cyfnewid Allwedd Gweinydd SSL.
+SSL_ERROR_CLIENT_KEY_EXCHANGE_FAILURE=Bu methiant amhenodol wrth brosesu ysgwyd llaw Cyfnewid Allwedd Gweinydd SSL.
+SSL_ERROR_ENCRYPTION_FAILURE=Methodd algorithm amgryptio swmp data yn y swit seiffr hwn.
+SSL_ERROR_DECRYPTION_FAILURE=Methodd algorithm dadgryptio swmp data yn y swit seiffr hwn.
+SSL_ERROR_SOCKET_WRITE_FAILURE=Merhodd ymgais i ysgrifennu data amgryptiedig i'r soced gwaelodol.
+SSL_ERROR_MD5_DIGEST_FAILURE=Methodd swyddogaeth crynhoi MD5.
+SSL_ERROR_SHA_DIGEST_FAILURE=Methodd swyddogaeth crynhoi SHA-1.
+SSL_ERROR_MAC_COMPUTATION_FAILURE=Methodd cyfrifiant MAC.
+SSL_ERROR_SYM_KEY_CONTEXT_FAILURE=Methu creu cyd-destun Allwedd Symetrig.
+SSL_ERROR_SYM_KEY_UNWRAP_FAILURE=Methu dadlapio'r allwedd Symetrig yn neges Cyfnewid Allwedd Cleient.
+SSL_ERROR_PUB_KEY_SIZE_LIMIT_EXCEEDED=Ceisiodd Gweinydd SSL â defnyddio allwedd gyhoeddus domestig gyda swit seiffr allforio.
+SSL_ERROR_IV_PARAM_FAILURE=Methodd cod PKCS11 â throsi IV i baram.
+SSL_ERROR_INIT_CIPHER_SUITE_FAILURE=Methu cychwyn y swit seiffr hwn.
+SSL_ERROR_SESSION_KEY_GEN_FAILURE=Methodd y cleient â chynhyrchu allweddi sesiwn ar gyfer sesiwn SSL.
+SSL_ERROR_NO_SERVER_KEY_FOR_ALG=Nid oes gan y gweinydd allwedd ar gyfer ymgais algoryddm cyfnewid allweddi.
+SSL_ERROR_TOKEN_INSERTION_REMOVAL=Mewnosodwyd neu dynnwyd tocyn PKCS#11 wrth i'r weithred fod mewn grym.
+SSL_ERROR_TOKEN_SLOT_NOT_FOUND=Ni fu modd canfod tocyn PKCS#11 i gyflawni'r weithredu.
+SSL_ERROR_NO_COMPRESSION_OVERLAP=Methu cyfathrebu'n ddiogel gyda'r cyfoed: dim algorithmau(au) cywasgu cyffredin.
+SSL_ERROR_HANDSHAKE_NOT_COMPLETED=Methu cychwyn ysgwyd llaw SSL arall nes i'r ysgwyd llaw cyfredol ddod i ben.
+SSL_ERROR_BAD_HANDSHAKE_HASH_VALUE=Wedi derbyn gwerthoedd hash ysgwyd llaw anghywir gan y cyfoed.
+SSL_ERROR_CERT_KEA_MISMATCH=Nid oes modd defnyddio'r dystysgrif hon gyda'r algorythm cyfnewid allwedd hwn.
+SSL_ERROR_NO_TRUSTED_SSL_CLIENT_CA=Nid oes ymddiriedaeth i awdurdod tystysgrifo ar gyfer dilysu cleient SSL.
+SSL_ERROR_SESSION_NOT_FOUND=Nid yw enw sesiwn SSL y cleient wedi ei ganfod yn storfa dros dro sesiwn y gweinydd.
+SSL_ERROR_DECRYPTION_FAILED_ALERT=Methodd y cyfoed â dadgryptio cofnod SSL mae wedi ei derbyn.
+SSL_ERROR_RECORD_OVERFLOW_ALERT=Derbyniodd y cyfoed gofnod SSL sy'n hirach na'r hyn ganiateir.
+SSL_ERROR_UNKNOWN_CA_ALERT=Nid yw'r cyfoed yn adnabod nac ymddiried yn y AT sydd wedi cyhoeddi eich tystysgrif.
+SSL_ERROR_ACCESS_DENIED_ALERT=Derbyniodd y cyfoed dystysgrif dilys , ond gwrthodwyd mynediad.
+SSL_ERROR_DECODE_ERROR_ALERT=Nid oedd y cyfoed yn gallu dadgodio neges ysgwyd llaw SSL.
+SSL_ERROR_DECRYPT_ERROR_ALERT=Mae'r cyfoed yn cofnodi methiant llofnod dilysu neu gyfnewid allweddi.
+SSL_ERROR_EXPORT_RESTRICTION_ALERT=Mae'r cyfoed yn cofnodi negodi nad yw'n gytûn â'r rheoliadau allforio.
+SSL_ERROR_PROTOCOL_VERSION_ALERT=Mae'r cofnod yn cofnodi ferwiwn protocol anghymarus neu heb ei gynnal.
+SSL_ERROR_INSUFFICIENT_SECURITY_ALERT=Mae'r gweinydd angen seiffr mwy diogel na'r rhai sy'n cael eu cynnal gan y cleient.
+SSL_ERROR_INTERNAL_ERROR_ALERT=Mae'r cyfoed yn nodi gwall mewnol.
+SSL_ERROR_USER_CANCELED_ALERT=Mae'r cyfoed wedi diddymu ysgwyd llaw.
+SSL_ERROR_NO_RENEGOTIATION_ALERT=Nid yw'r cyfoed yn caniatáu ailnegodi paramedrau diogelwch SSL.
+SSL_ERROR_SERVER_CACHE_NOT_CONFIGURED=Nid yw storfa dros dro gweinydd SSL wedi ei ffurfweddu na'i analluogi ar gyfer y soced hwn.
+SSL_ERROR_UNSUPPORTED_EXTENSION_ALERT=Nid yw'r cyfoed SSL yn cynnal yr estyniad helo TLS gofynnwys amdano.
+SSL_ERROR_CERTIFICATE_UNOBTAINABLE_ALERT=Nid yw'r cyfoed SSL y gallu cael eich tystysgrif o'r URL darparwyd.
+SSL_ERROR_UNRECOGNIZED_NAME_ALERT=Nid oes gan y cyfoed SSL dystysgrif ar gyfer yr enw DNS gofynnwyd amdani.
+SSL_ERROR_BAD_CERT_STATUS_RESPONSE_ALERT=Nid oedd y cyfoed SSL yn gallu cael ymateb OCSP ar gyfer ei dystysgrif.
+SSL_ERROR_BAD_CERT_HASH_VALUE_ALERT=Adroddodd cyfoed yr SSL gwerth hash tystysgrif gwael.
+SSL_ERROR_RX_UNEXPECTED_NEW_SESSION_TICKET=Mae SSL wedi derbyn neges ysgwyd llaw Tocyn Sesiwn Newydd annisgwyl.
+SSL_ERROR_RX_MALFORMED_NEW_SESSION_TICKET=Mae SSL wedi derbyn neges ysgwyd llaw Tocyn Sesiwn Newydd.
+SSL_ERROR_DECOMPRESSION_FAILURE=Mae SSL wedi derbyn cofnod cywasgedig nad oedd modd ei datgywasgu.
+SSL_ERROR_RENEGOTIATION_NOT_ALLOWED=Nid oes modd ail negodi ar y soced SSL hwn.
+SSL_ERROR_UNSAFE_NEGOTIATION=Ceisiodd y cyfoed ysgwyd llaw hen ffurf (bregus posib).
+SSL_ERROR_RX_UNEXPECTED_UNCOMPRESSED_RECORD=Derbyniodd SSL gofnod datgywasgedig annisgwyl.
+SSL_ERROR_WEAK_SERVER_EPHEMERAL_DH_KEY=Derbyniodd SSL allwedd gwan Diffie-Hellman darfodedig yn neges ysgwyd llaw Cyfnewidiad Allwedd Gweinydd.
+SSL_ERROR_NEXT_PROTOCOL_DATA_INVALID=Derbyniodd SSL ddata estyniad NPN annilys.
+SSL_ERROR_FEATURE_NOT_SUPPORTED_FOR_SSL2=Nid yw'r nodwedd SSL hwn yn cael ei gynnal ar gyfer cysylltiadau SSL 2.0.
+SSL_ERROR_FEATURE_NOT_SUPPORTED_FOR_SERVERS=Nid yw'r nodweddion SSL hyn yn cael eu cynnal ar weinyddion.
+SSL_ERROR_FEATURE_NOT_SUPPORTED_FOR_CLIENTS=Nid yw'r nodweddion SSL hyn yn cael eu cynnal ar raglenni.
+SSL_ERROR_INVALID_VERSION_RANGE=Nid ys ystod fersiwn SSL yn ddilys.
+SSL_ERROR_CIPHER_DISALLOWED_FOR_VERSION=Dewisodd cyfoed swît seiffr SSL sydd wedi ei atal ar gyfer y protocol fersiwn yma.
+SSL_ERROR_RX_MALFORMED_HELLO_VERIFY_REQUEST=Mae SSL wedi derbyn neges ysgwyd llaw Hello Verify Request anffurf.
+SSL_ERROR_RX_UNEXPECTED_HELLO_VERIFY_REQUEST=Mae SSL wedi derbyn neges ysgwyd llaw Hello Verify Request annisgwyl.
+SSL_ERROR_FEATURE_NOT_SUPPORTED_FOR_VERSION=Nid yw'r nodwedd SSL hwn yn cael ei gynnal ar gyfer y fersiwn protocol.
+SSL_ERROR_RX_UNEXPECTED_CERT_STATUS=Mae SSL wedi derbyn neges ysgwyd llaw Statws Tystysgrif annisgwyl.
+SSL_ERROR_UNSUPPORTED_HASH_ALGORITHM=Algorithm hash anghynaledig wedi ei ddefnyddio gan gyfoed TLS.
+SSL_ERROR_DIGEST_FAILURE=Methodd swyddogaeth crynhoi.
+SSL_ERROR_INCORRECT_SIGNATURE_ALGORITHM=Algorithm llofnod anghywir wedi ei bennu mewn elfen llofnod digidol.
+SSL_ERROR_NEXT_PROTOCOL_NO_CALLBACK=Roedd yr estyniad negydu protocol yn barod ond cafodd yr adalw ei glirio cyn fod ei angen.
+SSL_ERROR_NEXT_PROTOCOL_NO_PROTOCOL=Nid yw'r gweinydd yn cynnal protocolau mae'r client yn ei hysbysu yn yr estyniad ALPN.
+SSL_ERROR_INAPPROPRIATE_FALLBACK_ALERT=Gwrthododd y gweinydd yr ysgwyd llaw oherwydd i'r client israddio i fersiwn TLS is na mae'r gweinydd yn ei gynnal.
+SSL_ERROR_WEAK_SERVER_CERT_KEY=Mae tystysgrif y gweinydd yn cynnwys allwedd gyhoeddus sy'n rhy wan.
+SSL_ERROR_RX_SHORT_DTLS_READ=Dim digon o le ar y byffer ar gyfer cofnod DTLS.
+SSL_ERROR_NO_SUPPORTED_SIGNATURE_ALGORITHM=Heb ffurfweddu algorithm llofnod TLS sy'n cael ei gynnal.
+SSL_ERROR_UNSUPPORTED_SIGNATURE_ALGORITHM=Mae'r cyfoed yn defnyddio cyfuniad o lofnod a'r algorithm hash sydd ddim yn cael ei gynnal.
+SSL_ERROR_MISSING_EXTENDED_MASTER_SECRET=Mae'r cyfoed wedi ceisio ailgychwyn heb yr estyniad extended_master_secret cywir.
+SSL_ERROR_UNEXPECTED_EXTENDED_MASTER_SECRET=Mae'r cyfoed wedi ceisio ailgychwyn gyda estyniad extended_master_secret annisgwyl.
+SEC_ERROR_IO=Digwyddodd gwall I/O yn ystod dilysu diogelwch.
+SEC_ERROR_LIBRARY_FAILURE=methiant llyfrgell diogelwch.
+SEC_ERROR_BAD_DATA=llyfrgell diogelwch: derbyniwyd data gwael.
+SEC_ERROR_OUTPUT_LEN=llyfrgell diogelwch: gwall hyd allbwn.
+SEC_ERROR_INPUT_LEN=mae'r llyfrgell diogelwch wedi profi gwall hyd mewnbwn.
+SEC_ERROR_INVALID_ARGS=llyfrgell diogewlch: ymrysonderau annilys.
+SEC_ERROR_INVALID_ALGORITHM=llyfrgell diogewlch: algorithm annilys.
+SEC_ERROR_INVALID_AVA=llyfrgell diogelwch: AVA annilys.
+SEC_ERROR_INVALID_TIME=Llinyn amser fformatiwyd yn annilys.
+SEC_ERROR_BAD_DER=llyfrgell diogelwch: neges amgodiad-DER wedi ei fformatio'n annilys.
+SEC_ERROR_BAD_SIGNATURE=Mae gan y tystysgrif cyfoed lofnod annilys.
+SEC_ERROR_EXPIRED_CERTIFICATE=Tystysgrif Cyfoed wedi dod i ben.
+SEC_ERROR_REVOKED_CERTIFICATE=Tystysgrif Cyfoed wedi ei atal.
+SEC_ERROR_UNKNOWN_ISSUER=Cyhoeddwr Tystysgrif Cyfoed heb ei adnabod.
+SEC_ERROR_BAD_KEY=Allwedd cyhoeddus y cyfoed yn annilys.
+SEC_ERROR_BAD_PASSWORD=Mae'r cyfrinair diogelwch yn anghywir.
+SEC_ERROR_RETRY_PASSWORD=Cyfrinair newydd yn anghywir. Ceisiwch eto.
+SEC_ERROR_NO_NODELOCK=llyfrgell diogelwch: dim clo nod.
+SEC_ERROR_BAD_DATABASE=llyfrgell diogewlch: cronfa ddata gwael.
+SEC_ERROR_NO_MEMORY=llyfrgell diogewlch: methiant dynodicof.
+SEC_ERROR_UNTRUSTED_ISSUER=Cyhoeddwr tystysgrif cyfoed wedi ei nodi fel annibynadwy gan y defnyddiwr.
+SEC_ERROR_UNTRUSTED_CERT=Tstysgrif cyfoed wedi ei nodi fel annibynadwy gan y defnyddiwr.
+SEC_ERROR_DUPLICATE_CERT=Mae'r tystysgrif yn bodoli yn eich cronfa ddata.
+SEC_ERROR_DUPLICATE_CERT_NAME=Mae enw'r dystysgrif llwythwyd i lawr yn dyblygu un sydd yn eich cronfa ddata.
+SEC_ERROR_ADDING_CERT=Gwall ychwanegu tystysgrif i'r gronfa ddata.
+SEC_ERROR_FILING_KEY=Gwall ail-lanw allwedd ar gyfer y dystysgrif.
+SEC_ERROR_NO_KEY=Nid oes modd dod o hyd i allwedd breifat y dystysgrif yng gronfa ddata allweddi
+SEC_ERROR_CERT_VALID=Mae'r dystysgrif yn ddilys.
+SEC_ERROR_CERT_NOT_VALID=Nid yw'r dystysgrif yn ddilys.
+SEC_ERROR_CERT_NO_RESPONSE=Llyfrgell Tyst: Dim Ymateb
+SEC_ERROR_EXPIRED_ISSUER_CERTIFICATE=Ma tystysgrif cyhoeddwr y dystysgrif wedi dod i ben. Gwiriwch ddyddiad ac amser eich system.
+SEC_ERROR_CRL_EXPIRED=Mae CRL cyhoeddwr y dystysgrif wedi dod i ben. Diweddarwch neu gwiriwch ddyddiad ac amser eich system.
+SEC_ERROR_CRL_BAD_SIGNATURE=Mae i CRL cyhoeddwr y dystysgrif lofnod annilys.
+SEC_ERROR_CRL_INVALID=Mae i'r CRL newydd fformat annilys.
+SEC_ERROR_EXTENSION_VALUE_INVALID=Mae gwerth estyniad tystysgrif yn annilys.
+SEC_ERROR_EXTENSION_NOT_FOUND=Heb ganfod estyniad tystysgrif.
+SEC_ERROR_CA_CERT_INVALID=Tystysgrif y cyhoeddwr yn annilys.
+SEC_ERROR_PATH_LEN_CONSTRAINT_INVALID=Mae cyfyniad hyd llwybr y dystysgrif yn annilys.
+SEC_ERROR_CERT_USAGES_INVALID=Mae maes defnydd tystysgrif yn annilys.
+SEC_INTERNAL_ONLY=**Modiwl Mewnol YN UNIG**
+SEC_ERROR_INVALID_KEY=Nid yw'r allwedd yn cynnal y weithred hon.
+SEC_ERROR_UNKNOWN_CRITICAL_EXTENSION=Mae'r dystysgrif yn cynnwys estyniad critigol anhysbys.
+SEC_ERROR_OLD_CRL=Nid yw'r CRL yn hwyrach na'r un gyfredol.
+SEC_ERROR_NO_EMAIL_CERT=Heb ei hamgryptio na'i harwyddo: nid oes gennych dystysgrif e-bost eto.
+SEC_ERROR_NO_RECIPIENT_CERTS_QUERY=Heb ei hamgryptio: nid oes gennych dystysgrif ar gyfer pob un derbynnydd.
+SEC_ERROR_NOT_A_RECIPIENT=Methu dadgryptio: nid ydych yn dderbynnydd, neu heb ganfod tystysgrif cytûn neu allwedd breifat.
+SEC_ERROR_PKCS7_KEYALG_MISMATCH=Methu dadgryptio: nid yw amgryptiad yr algorithm yn gytûn â'ch tystysgrif.
+SEC_ERROR_PKCS7_BAD_SIGNATURE=Methodd dilysu llofnod: heb ganfod llofnodwr, wedi canfod gormod o lofnodwyr neu data amhriodol neu llwgr.
+SEC_ERROR_UNSUPPORTED_KEYALG=Allwedd algorithm heb ei gynnal neu anhysbys.
+SEC_ERROR_DECRYPTION_DISALLOWED=Methu dadgryptio: wedi ei amgryptio gan ddefnyddio algorithm gwaharddedig neu faint allwedd.
+XP_SEC_FORTEZZA_BAD_CARD=Nid yw cerdyn Fortezza wedi ei gychwyn yn gywir. Tynnwch y cerdyn a'i ddychwelyd ar y cyhoeddwr.
+XP_SEC_FORTEZZA_NO_CARD=Heb ganfod cerdyn Fortezza
+XP_SEC_FORTEZZA_NONE_SELECTED=Heb ddewis cerdyn Fortezza
+XP_SEC_FORTEZZA_MORE_INFO=Dewiswch bersonoliaeth i dderbyn mwy o wybodaeth amdano
+XP_SEC_FORTEZZA_PERSON_NOT_FOUND=Heb ddarganfod personoliaeth
+XP_SEC_FORTEZZA_NO_MORE_INFO=Dim rhagor o wybodaeth ar Personoliaeth hwnnw
+XP_SEC_FORTEZZA_BAD_PIN=Pin annilys
+XP_SEC_FORTEZZA_PERSON_ERROR=Methu cychwyn personoliaethau Fortezza.
+SEC_ERROR_NO_KRL=Heb ganfod KRL ar gyfer tystysgrif y wefan.
+SEC_ERROR_KRL_EXPIRED=Mae KRL y wefan wedi dod i ben.
+SEC_ERROR_KRL_BAD_SIGNATURE=Mae llofnod annilys i KRL tystysgrif y wefan.
+SEC_ERROR_REVOKED_KEY=Mae allwedd tystysgrif y wefan honn wedi ei therfynnu.
+SEC_ERROR_KRL_INVALID=Mae fformat annilys i'r KRL newydd.
+SEC_ERROR_NEED_RANDOM=llyfrgell diogelwch: angen data hap.
+SEC_ERROR_NO_MODULE=llyfrgell diogelwch: nid oes modiwl diogelwch all gyflawni'r weithred angenrheidiol.
+SEC_ERROR_NO_TOKEN=Nid yw'r cerdyn neu docyn diogelwch yn bodoli, angen ei gychwyn neu wedi ei dynnu.
+SEC_ERROR_READ_ONLY=llyfrgell diogelwch: cronfa ddata darllen yn unig.
+SEC_ERROR_NO_SLOT_SELECTED=Heb ddewis slot neu docyn.
+SEC_ERROR_CERT_NICKNAME_COLLISION=Mae tystysgrif gyda'r un llysenw yn bodoli eisoes.
+SEC_ERROR_KEY_NICKNAME_COLLISION=Mae allwedd gyda'r un llysenw yn bodoli eisoes.
+SEC_ERROR_SAFE_NOT_CREATED=gwall wrth greu gwrthrych diogel
+SEC_ERROR_BAGGAGE_NOT_CREATED=gwall werth greu gwrthrych pecyn
+XP_JAVA_REMOVE_PRINCIPAL_ERROR=Methu tynnu'r prif
+XP_JAVA_DELETE_PRIVILEGE_ERROR=Methu dileu'r fraint
+XP_JAVA_CERT_NOT_EXISTS_ERROR=Nid oes gan y prif dystysgrif
+SEC_ERROR_BAD_EXPORT_ALGORITHM=Nid oes caniatâd i'r algorithm angenrheidiol.
+SEC_ERROR_EXPORTING_CERTIFICATES=Gwall wrth geisio allforio tystysgrifau.
+SEC_ERROR_IMPORTING_CERTIFICATES=Gwall wrth geisio mewnforio tystysgrifau.
+SEC_ERROR_PKCS12_DECODING_PFX=Methu mewnforio. Gwall dadgodio. Nid yw'r ffeil yn ddilys.
+SEC_ERROR_PKCS12_INVALID_MAC=Methu mewnforio. MAC annilys. Cyfrinair anghywir neu ffeil llwgr.
+SEC_ERROR_PKCS12_UNSUPPORTED_MAC_ALGORITHM=Methu mewnforio. Nid yw'r algorithm MAC yn cael ei gynnal.
+SEC_ERROR_PKCS12_UNSUPPORTED_TRANSPORT_MODE=Methu mewnforio. Dim ond cywirdeb cyfrinair a moddau preifatrwydd sy'n cael eu cynnal.
+SEC_ERROR_PKCS12_CORRUPT_PFX_STRUCTURE=Methu mewnforio. Mae strwythur y ffeil yn llwgr.
+SEC_ERROR_PKCS12_UNSUPPORTED_PBE_ALGORITHM=Methu mewnforio. Nid yw algorithm yr amgryptio'n cael ei gynnal.
+SEC_ERROR_PKCS12_UNSUPPORTED_VERSION=Methu mewnforio. Nid yw fersiwn y ffeil yn cael ei chynnal.
+SEC_ERROR_PKCS12_PRIVACY_PASSWORD_INCORRECT=Methu mewnforio. Cyfrinair preifatrwydd anghywir.
+SEC_ERROR_PKCS12_CERT_COLLISION=Methu mewnforio. Mae'r un llysenw yn bodoli eisoes yn y gronfa ddata.
+SEC_ERROR_USER_CANCELLED=Pwysodd y defnyddiwr diddymu.
+SEC_ERROR_PKCS12_DUPLICATE_DATA=Heb ei fewnforio, eisoes yn y gronfa ddata.
+SEC_ERROR_MESSAGE_SEND_ABORTED=Heb anfon y neges.
+SEC_ERROR_INADEQUATE_KEY_USAGE=Defnydd allwedd y dystysgrif yn annigonol ar gyfer y weithred ymgeisiwyd.
+SEC_ERROR_INADEQUATE_CERT_TYPE=Nid yw'r math o dystysgrif wedi ei gymeradwyo ar gyfer y rhaglen.
+SEC_ERROR_CERT_ADDR_MISMATCH=Nid yw'r cyfeiriad yn y dysstysgrif llofnodi yn cydfynd â'r cyferiad ym mhenyn y neges.
+SEC_ERROR_PKCS12_UNABLE_TO_IMPORT_KEY=Methu mewnforio. Gwall wrth geisio mewnforio'r allwedd breifat.
+SEC_ERROR_PKCS12_IMPORTING_CERT_CHAIN=Methu mewnforio. Gwall wrth geisio mewnforio cadwyn tystysgrif.
+SEC_ERROR_PKCS12_UNABLE_TO_LOCATE_OBJECT_BY_NAME=Methu allforio. Methu lleoli tystysgrif neu allwedd yn ôl tystysgrif.
+SEC_ERROR_PKCS12_UNABLE_TO_EXPORT_KEY=Methu allforio. Nid oedd modd canfod yr Allwedd Breifat a'i hallforio.
+SEC_ERROR_PKCS12_UNABLE_TO_WRITE=Methu allforio. Methu ysgrifennu i'r ffeil allforio.
+SEC_ERROR_PKCS12_UNABLE_TO_READ=Methu mewnforio. Methu darllen y ffeil mewnforio.
+SEC_ERROR_PKCS12_KEY_DATABASE_NOT_INITIALIZED=Methu allforio. Cronfa ddata'r allwedd yn llwgr neu wedi ei dileu.
+SEC_ERROR_KEYGEN_FAIL=Methu cynhyrchu par o allweddi cyhoeddus/preifat.
+SEC_ERROR_INVALID_PASSWORD=Mae'r cyfrinair rhoddwyd yn annilys. Dewiswch un arall.
+SEC_ERROR_RETRY_OLD_PASSWORD=Mae'r hen gyfrinair wedi ei gosod yn anghywir. Ceisiwch eto.
+SEC_ERROR_BAD_NICKNAME=Mae llysenw'r dystysgrif yn cael ei defnyddio eisoes.
+SEC_ERROR_NOT_FORTEZZA_ISSUER=Mae gan y cadwyn FORTEZZA cyfoed dystysgrif an FORTEZZA.
+SEC_ERROR_CANNOT_MOVE_SENSITIVE_KEY=Nid oes modd symud allwedd sensitif i'r slot lle mae ei hangen.
+SEC_ERROR_JS_INVALID_MODULE_NAME=Enw modiwl annilys.
+SEC_ERROR_JS_INVALID_DLL=Llwybr/enw ffeil modiwl annilys
+SEC_ERROR_JS_ADD_MOD_FAILURE=Methu ychwanegu modiwl
+SEC_ERROR_JS_DEL_MOD_FAILURE=Methu dileu modiwl
+SEC_ERROR_OLD_KRL=Nid yw'r KRL newydd yn hwyrach na'r un cyfredol.
+SEC_ERROR_CKL_CONFLICT=Mae gan y CKL gyhoeddwr gwahanol i'r CKL cyfredol. Dilëwch y CKL cyfredol.
+SEC_ERROR_CERT_NOT_IN_NAME_SPACE=Nid oes gan Awdurdod Tystysgrifo'r dystysgrif hon hawl i gyhoeddi tystysgrif yn yr enw hwn.
+SEC_ERROR_KRL_NOT_YET_VALID=Nid yw rhestr dileu'r allwedd ar gyfer y dystysgrif yn ddilys eto.
+SEC_ERROR_CRL_NOT_YET_VALID=Nid yw rhestr dileu'r dystysgrif ar gyfer y dystysgrif yn ddilys eto.
+SEC_ERROR_UNKNOWN_CERT=Nid oedd modd canfod y dystysgrif ofynnol.
+SEC_ERROR_UNKNOWN_SIGNER=Nid oedd modd canfod tystysgrif y llofnodwr.
+SEC_ERROR_CERT_BAD_ACCESS_LOCATION=Mae gan leoliad gweinydd statws y dystysgrif fformat annilys.
+SEC_ERROR_OCSP_UNKNOWN_RESPONSE_TYPE=Nid oes modd dadgodio ymateb OCSP yn llawn; mae o fath anhysbys.
+SEC_ERROR_OCSP_BAD_HTTP_RESPONSE=Dychwelodd gweinydd OCSP ddata HTTP annisgwyl/annilys.
+SEC_ERROR_OCSP_MALFORMED_REQUEST=Mae'r gweinydd OCSP wedi pennu'r cais fel un llwgr neu heb ei ffurfio'n gywir.
+SEC_ERROR_OCSP_SERVER_ERROR=Profodd y gweinydd OCSP wall mewnol.
+SEC_ERROR_OCSP_TRY_SERVER_LATER=Mae gweinydd yr OCSP yn awgrymu y dylech geisio eto.
+SEC_ERROR_OCSP_REQUEST_NEEDS_SIG=Mae angen llofnod ar gyfer y gweinydd OCSP.
+SEC_ERROR_OCSP_UNAUTHORIZED_REQUEST=Mae'r gweinydd OCSP wedi gwrthod y cais fel un anawdurdodedig.
+SEC_ERROR_OCSP_UNKNOWN_RESPONSE_STATUS=Dychwelodd y gweinydd OCSP statws heb ei gydnabod.
+SEC_ERROR_OCSP_UNKNOWN_CERT=Nid oes gan y gweinydd OCSP statws ar gyfer y dystysgrif.
+SEC_ERROR_OCSP_NOT_ENABLED=Rhaid galluogi OCSP cyn cyflawni'r weithred.
+SEC_ERROR_OCSP_NO_DEFAULT_RESPONDER=Rhaid gosod ymatebwr rhagosodedig yr OCSP cyn cyflawni'r weithred.
+SEC_ERROR_OCSP_MALFORMED_RESPONSE=Roedd ymateb y gweinydd OCSP yn llwgr neu heb ei ffurfio'n gywir.
+SEC_ERROR_OCSP_UNAUTHORIZED_RESPONSE=Nid oes gan lofnodwr ymateb yr OCSP yr awdurdod i ddarparu statws y dystysgrif.
+SEC_ERROR_OCSP_FUTURE_RESPONSE=Nid yw ymateb yr OCSP nyn ddilys eto (mae'n cynnwys dyddiad yn y dyfodol).
+SEC_ERROR_OCSP_OLD_RESPONSE=Mae ymateb yr OCSP yn cynnwys hen ddata.
+SEC_ERROR_DIGEST_NOT_FOUND=Heb ganfod Crynodeb CMS neu PKCS #7 yn y neges gyda'r llofnod.
+SEC_ERROR_UNSUPPORTED_MESSAGE_TYPE=Nid yw'r math o neges CMS neu PKCS #7 yn cael eu cynnal.
+SEC_ERROR_MODULE_STUCK=Nid oeddd modd tynnu modiwl PKCS #11 am ei fod yn cael ei ddefnyddio.
+SEC_ERROR_BAD_TEMPLATE=Methu dadgodio data ASN.1. Roedd y templed yn annilys.
+SEC_ERROR_CRL_NOT_FOUND=Methu canfod CRL cytûn.
+SEC_ERROR_REUSED_ISSUER_AND_SERIAL=Rydych yn ceisio mewnforio tystysgrif gyda'r un cyhoeddwr/cyfres a'r dystysgrif gyfredol, ond nid yr un dystysgrif ydyw.
+SEC_ERROR_BUSY=Meddodd yr NSS â chau. Gwrthychau yn dal mewn defnydd.
+SEC_ERROR_EXTRA_INPUT=Mae'r neges DER amgodedig yn cynnwys data ychwanegol heb ei ddefnyddio.
+SEC_ERROR_UNSUPPORTED_ELLIPTIC_CURVE=Cromlin eliptig heb ei gynnal.
+SEC_ERROR_UNSUPPORTED_EC_POINT_FORM=Ffurf pwynt cromlin eliptig heb ei gynnal.
+SEC_ERROR_UNRECOGNIZED_OID=Adnabyddwr Gwrthrychau Anhysbys.
+SEC_ERROR_OCSP_INVALID_SIGNING_CERT=Tysytysgrif llofnodi OCSP anniltys yn ymateb yr OCSP.
+SEC_ERROR_REVOKED_CERTIFICATE_CRL=Mae'r dystysgrif wedi ei diddymu yn rhestr diddymu cyhoeddwr y dystysgrif.
+SEC_ERROR_REVOKED_CERTIFICATE_OCSP=Mae tystysgrif adrodd ymatebion OCSP y cyhoeddwr wedi ei diddymu.
+SEC_ERROR_CRL_INVALID_VERSION=Mae gan Rhestr Diddymu Tystysgrifau'r Cyhoeddwr rhif fersiwn anhysbys.
+SEC_ERROR_CRL_V1_CRITICAL_EXTENSION=Mae gan Rhestr Diddymu Tystysgrif V1 y cyhoeddwr estyniad critigol.
+SEC_ERROR_CRL_UNKNOWN_CRITICAL_EXTENSION=Mae gan Rhestr Diddymu Tystysgrif V2 y cyhoeddwr estyniad critigol anhysbys.
+SEC_ERROR_UNKNOWN_OBJECT_TYPE=Gwrthrych o fath anhysbys wedi ei bennu.
+SEC_ERROR_INCOMPATIBLE_PKCS11=Mae gyrrwr PKCS #11 yn tarfu'r manyleb mewn dull anghymarus.
+SEC_ERROR_NO_EVENT=Mae digwyddiad slot newydd ar gael ar hyn o bryd.
+SEC_ERROR_CRL_ALREADY_EXISTS=Mae'r CRL yn bodoli eisoes.
+SEC_ERROR_NOT_INITIALIZED=Nid yw'r NSS wedi ei gychwyn.
+SEC_ERROR_TOKEN_NOT_LOGGED_IN=Methodd y weithred gan nad yw tocyn PKCS#11 wedi ei fewngofnodi.
+SEC_ERROR_OCSP_RESPONDER_CERT_INVALID=Mae ffurfweddiad tystysgrif ymatebwr OCSP yn anilys.
+SEC_ERROR_OCSP_BAD_SIGNATURE=Mae gan ymateb yr OCSP lofnod annilys.
+SEC_ERROR_OUT_OF_SEARCH_LIMITS=Mae chwilio dilysu'r dystysgrif tu llan i derfynnau ei chwilio
+SEC_ERROR_INVALID_POLICY_MAPPING=Mae mapio polisi yn cynnwys anypolicy
+SEC_ERROR_POLICY_VALIDATION_FAILED=Mae cadwyn y dystysgrif yn methu'r dilysiad polisi
+SEC_ERROR_UNKNOWN_AIA_LOCATION_TYPE=Math lleoliad anhysbys yn estyniad tystysgrif AIA
+SEC_ERROR_BAD_HTTP_RESPONSE=Dychwelodd y gweinydd ymateb HTTP gwael
+SEC_ERROR_BAD_LDAP_RESPONSE=Dychwelodd y gweinydd ymateb LDAP gwael
+SEC_ERROR_FAILED_TO_ENCODE_DATA=Methwyd amgosio data gydag amgodiwr ASN1
+SEC_ERROR_BAD_INFO_ACCESS_LOCATION=Lleoliad mynediad gwybodaeth gwael mewn estyniad tystysgrif
+SEC_ERROR_LIBPKIX_INTERNAL=Digwyddodd gwall mewnol libpkix yn ystod dilysiad tystysgrif.
+SEC_ERROR_PKCS11_GENERAL_ERROR=Dychwelodd modiwl PKCS #11 CKR_GENERAL_ERROR, gan awgrymu fod gwall anadferadwy wedi digwydd.
+SEC_ERROR_PKCS11_FUNCTION_FAILED=Dychwelodd PKCS #11 CKR_FUNCTION_FAILED, gan awgrymu nad oedd modd cyflawni'r swyddogaeth ofynnol. Efallai bydd cyflawni'r un weithred eto'n llwyddo.
+SEC_ERROR_PKCS11_DEVICE_ERROR=Dychwelodd modiwl PKCS #11 CKR_DEVICE_ERROR, gan awgrymu fod yna broblem gyda'r tocyn neu'r slot.
+SEC_ERROR_BAD_INFO_ACCESS_METHOD=Dull mynediad gwybodaeth anhysbys mewn estyniad tystysgrif.
+SEC_ERROR_CRL_IMPORT_FAILED=Gwall wrth geisio mewnforio CRL.
+SEC_ERROR_EXPIRED_PASSWORD=Mae'r cyfrinair wedi dod i ben.
+SEC_ERROR_LOCKED_PASSWORD=Mae'r cyfrinair wedi ei gloi.
+SEC_ERROR_UNKNOWN_PKCS11_ERROR=Gwall PKCS #11 anhysbys.
+SEC_ERROR_BAD_CRL_DP_URL=URL annilys neu heb ei gynnal yn enw pwynt dosbarthiad CRL.
+SEC_ERROR_CERT_SIGNATURE_ALGORITHM_DISABLED=Cafodd y dystysgrif ei llofnodi gan ddefnyddio algorithm llofnod sydd wedi ei analluogi am nad yw'n ddiogel.
+MOZILLA_PKIX_ERROR_KEY_PINNING_FAILURE=Mae'r gweinydd yn defnyddio pinio allwedd (HPKP) ond nid oedd modd cynhyrchu cadwyn tystysgrif ymddiriedig sy'n cyd-fynd a'r set pinnau. Nid oes mod gwrthwneud torri pinio allweddi.
+MOZILLA_PKIX_ERROR_CA_CERT_USED_AS_END_ENTITY=Mae'r gweinydd yn defnyddio tystysgrif gydag estyniad cyfyngiadau sylfaenol sy'n ei ddynodi fel yr awdurdod tystysgrifo. Ar gyfer tystysgrifau sydd wedi eu rhyddhau'n briodol, ni ddylai hyn fod yn wir.
+MOZILLA_PKIX_ERROR_INADEQUATE_KEY_SIZE=Cyflwynodd y gweinydd dystysgrif sydd ag allwedd sy'n rhy fach i greu cysylltiad diogel.
+MOZILLA_PKIX_ERROR_V1_CERT_USED_AS_CA=Defnyddiwyd tystysgrif X.509 fersiwn 1 nad yw'n angor ymddiriedaeth i gyhoeddi tystysgrif y wefan. Mae tystysgrifau X.509 fersiwn 1 yn anghymeradwy ac ni ddylent gael eu defnyddio i lofnodi tystysgrifau eraill.
+MOZILLA_PKIX_ERROR_NOT_YET_VALID_CERTIFICATE=Cyflwynodd y gweinydd dystysgrif nad yw eto'n ddilys.
+MOZILLA_PKIX_ERROR_NOT_YET_VALID_ISSUER_CERTIFICATE=Defnyddiwyd tystysgrif nad yw eto'n ddilys i gyhoeddi tystysgrif y gweinydd.
+MOZILLA_PKIX_ERROR_SIGNATURE_ALGORITHM_MISMATCH=Nid yw'r algorithm llofnod ym maes llofnod y dystysgrif yn cyd-fynd â'r algorithm ym maes signatureAlgorithm.
+MOZILLA_PKIX_ERROR_OCSP_RESPONSE_FOR_CERT_MISSING=Nid yw ymateb yr OCSP yn cynnwys statws y dystysgrif sy'n cael ei gwirio.
+MOZILLA_PKIX_ERROR_VALIDITY_TOO_LONG=Cyflwynodd y gweinydd dystysgrif sy'n ddilys am rhy hir.
+MOZILLA_PKIX_ERROR_REQUIRED_TLS_FEATURE_MISSING=Mae'r nodwedd TLS angenrheidiol ar goll.
+MOZILLA_PKIX_ERROR_INVALID_INTEGER_ENCODING=Cyflwynodd y gweinydd dystysgrif sy'n cynnwys math annilys o amgodio integer. Mae'r rhesymau cyffredin yn cynnwys rhifau cyfresol negyddol, moduli RSA negyddol, ac amgodio nad ydynt eu hangen bellach.
+MOZILLA_PKIX_ERROR_EMPTY_ISSUER_NAME=Cyflwynodd y gweinydd dystysgrif gydag enw cyhoeddwr penodol gwag.
+MOZILLA_PKIX_ERROR_ADDITIONAL_POLICY_CONSTRAINT_FAILED=Methodd cyfyngiad polisi ychwanegol wrth ddilysu'r dystysgrif hon.
+MOZILLA_PKIX_ERROR_SELF_SIGNED_CERT=Nid oes modd ymddiried yn y dystysgrif am ei fod wedi ei hunanlofnodi.
diff --git a/l10n-cy/security/manager/chrome/pipnss/pipnss.properties b/l10n-cy/security/manager/chrome/pipnss/pipnss.properties
new file mode 100644
index 0000000000..8260c5f109
--- /dev/null
+++ b/l10n-cy/security/manager/chrome/pipnss/pipnss.properties
@@ -0,0 +1,308 @@
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+CertPassPrompt=Rhowch y prif gyfrinair ar gyfer %S.
+
+CertPassPromptDefault=Rhowch eich prif gyfrinair.
+
+CertPasswordPrompt=Rhowch y cyfrinair ar gyfer y tocyn PKCS#11 %S.
+
+CertPasswordPromptDefault=Rhowch eich Prif Gyfrinair.
+
+# The following strings have special requirements: they must fit in a 32 or 64
+# bytes buffer after being encoded to UTF-8.
+#
+# It's possible to verify the length of a translation using the Browser Console
+# in Firefox and evaluating the following code:
+#
+# (new TextEncoder('utf-8').encode('YOURSTRING')).length
+#
+# Simply replace YOURSTRING with your translation.
+#
+# If it's not possible to produce an understandable translation within these
+# limits, keeping the English text is an acceptable workaround.
+
+# LOCALIZATION NOTE (RootCertModuleName): string limit is 64 bytes after
+# conversion to UTF-8.
+# length_limit = 64 bytes
+RootCertModuleName=Modiwl Gwreiddiau Builtin
+# LOCALIZATION NOTE (ManufacturerID): string limit is 32 bytes after conversion
+# to UTF-8.
+# length_limit = 32 bytes
+ManufacturerID=Mozilla.org
+# LOCALIZATION NOTE (LibraryDescription): string limit is 32 bytes after
+# conversion to UTF-8.
+# length_limit = 32 bytes
+LibraryDescription=Gwasanaethau Crypto Mewnol PSM
+# LOCALIZATION NOTE (TokenDescription): string limit is 32 bytes after
+# conversion to UTF-8.
+# length_limit = 32 bytes
+TokenDescription=Gwasanaethau Crypto Generig
+# LOCALIZATION NOTE (PrivateTokenDescription): string limit is 32 bytes after
+# conversion to UTF-8.
+# length_limit = 32 bytes
+PrivateTokenDescription=Dyfais Diogelwch Meddalwedd
+# LOCALIZATION NOTE (SlotDescription): string limit is 64 bytes after conversion
+# to UTF-8.
+# length_limit = 64 bytes
+SlotDescription=Gwasanaethau Cryptograffig Mewnol PSM
+# LOCALIZATION NOTE (PrivateSlotDescription): string limit is 64 bytes after
+# conversion to UTF-8.
+# length_limit = 64 bytes
+PrivateSlotDescription=Allweddi Preifat PSM
+# LOCALIZATION NOTE (Fips140TokenDescription): string limit is 32 bytes after
+# conversion to UTF-8.
+# length_limit = 32 bytes
+Fips140TokenDescription=Dyfais Diogelu Meddalwedd (FIPS)
+# LOCALIZATION NOTE (Fips140SlotDescription): string limit is 64 bytes after
+# conversion to UTF-8.
+# length_limit = 64 bytes
+Fips140SlotDescription=Gwasanaethau Tystysgrif ac Allwedd Cryptograffeg FIPS 140
+
+# LOCALIZATION NOTE (nick_template): $1s is the common name from a cert (e.g. "Mozilla"), $2s is the CA name (e.g. VeriSign)
+nick_template=%1$s's %2$s ID
+#These are the strings set for the ASN1 objects in a certificate.
+CertDumpCertificate=Tystysgrif
+CertDumpVersion=Fersiwn
+# LOCALIZATION NOTE (CertDumpVersionValue): %S is a version number (e.g. "3" in "Version 3")
+CertDumpVersionValue=Fersiwn %S
+CertDumpSerialNo=Rhif Cyfresol
+CertDumpMD2WithRSA=PKCS #1 MD2 Gydag Amgryptiad RSA
+CertDumpMD5WithRSA=PKCS #1 MD5 Gydag Amgryptiad RSA
+CertDumpSHA1WithRSA=PKCS #1 SHA-1 Gydag Amgryptiad RSA
+CertDumpSHA256WithRSA=PKCS #1 SHA-256 Gydag Amgryptiad RSA
+CertDumpSHA384WithRSA=PKCS #1 SHA-384 Gydag Amgryptiad RSA
+CertDumpSHA512WithRSA=PKCS #1 SHA-512 Gydag Amgryptiad RSA
+CertDumpDefOID=Dynodwr Gwrthrych (%S)
+CertDumpIssuer=Cyhoeddwr
+CertDumpSubject=Pwnc
+CertDumpAVACountry=C
+CertDumpAVAState=ST
+CertDumpAVALocality=L
+CertDumpAVAOrg=O
+CertDumpAVAOU=OU
+CertDumpAVACN=CN
+CertDumpUserID=UID
+CertDumpPK9Email=E
+CertDumpAVADN=DN
+CertDumpAVADC=DC
+CertDumpSurname=Cyfenw
+CertDumpGivenName=Enw Rhodd
+CertDumpValidity=Dilysrwydd
+CertDumpNotBefore=Nid Cyn
+CertDumpNotAfter=Nid ar Ôl
+CertDumpSPKI=Gwybodaeth Allwedd Gyhoeddus y Testun
+CertDumpSPKIAlg=Algorithm Allwedd Gyhoeddus y Testun
+CertDumpAlgID=Dynodwr Algorithm
+CertDumpParams=Paramedrau Algorithm
+CertDumpRSAEncr=Amgryptiad PKCS #1 RSA
+CertDumpRSAPSSSignature=Llofnod PKCS #1 RSASSA-PSS
+CertDumpRSATemplate=Modwlws (%S did):\n%S\nEsbonydd (%S did):\n%S
+CertDumpECTemplate=Maint allwedd: %S did\nHyd trefn pwynt sail: %S didau\nGwerth cyhoeddus:\n%S
+CertDumpIssuerUniqueID=Enw Unigryw'r Cyhoeddwr
+CertDumpSubjPubKey=Allwedd Gyhoeddus y Testun
+CertDumpSubjectUniqueID=Enw Unigryw'r Pwnc
+CertDumpExtensions=Estyniadau
+CertDumpSubjectDirectoryAttr=Priodweddau Cyfeiriadur Testun Tystysgrif
+CertDumpSubjectKeyID=Enw Allwedd Testun Tystysgrif
+CertDumpKeyUsage=Defnydd Tystysgrif Allweddol
+CertDumpSubjectAltName=Enw Arall Testun Tystysgrif
+CertDumpIssuerAltName=Enw Arall Cyhoeddwr Tystysgrifau
+CertDumpBasicConstraints=Cyfyngiad Sylfaenol Tystysgrif
+CertDumpNameConstraints=Cyfyngiad Enw Tystysgrif
+CertDumpCrlDistPoints=Pwyntiau Dosbarthu CRL
+CertDumpCertPolicies=Polisïau Tystysgrif
+CertDumpPolicyMappings=Mapio Polisi Tystysgrif
+CertDumpPolicyConstraints=Cyfyngiad Polisi Tystysgrif
+CertDumpAuthKeyID=Dynodwr Tystysgrif Allwedd Awdurdod
+CertDumpExtKeyUsage=Defnydd Allwedd Estynedig
+CertDumpAuthInfoAccess=Mynediad Gwybodaeth Awdurdod
+CertDumpAnsiX9DsaSignature=Llofnod ANSI X9.57 DSA
+CertDumpAnsiX9DsaSignatureWithSha1=Llofnod ANSI X9.57 DSA gyda Chrynodeb SHA1
+CertDumpAnsiX962ECDsaSignatureWithSha1=Llofnod ANSI X9.62 ECDSA gyda SHA1
+CertDumpAnsiX962ECDsaSignatureWithSha224=Llofnod ANSI X9.62 ECDSA gyda SHA224
+CertDumpAnsiX962ECDsaSignatureWithSha256=Llofnod ANSI X9.62 ECDSA gyda SHA256
+CertDumpAnsiX962ECDsaSignatureWithSha384=Llofnod ANSI X9.62 ECDSA gyda SHA384
+CertDumpAnsiX962ECDsaSignatureWithSha512=Llofnod ANSI X9.62 ECDSA gyda SHA512
+
+CertDumpKUSign=Llofnodi
+CertDumpKUNonRep=An-wrthodiad
+CertDumpKUEnc=Seiffro Allwedd
+CertDumpKUDEnc=Seiffro Data
+CertDumpKUKA=Cytundeb Allwedd
+CertDumpKUCertSign=Llofnodwr Tystysgrif
+CertDumpKUCRLSigner=Llofnodwr CRL
+CertDumpCritical=Critigol
+CertDumpNonCritical=Heb fod yn Gritigol
+CertDumpSigAlg=Algorithm Llofnod Tystysgrif
+CertDumpCertSig=Gwerth Llofnod Tystysgrif
+CertDumpExtensionFailure=Gwall: Methu prosesu'r estyniad
+CertDumpIsCA=Yn Awdurdod Tystysgrif
+CertDumpIsNotCA=Nid yw'n Awdurdod Tystysgrif
+CertDumpPathLen=Nifer mwyaf o CA canolig: %S
+CertDumpPathLenUnlimited=diderfyn
+CertDumpEKU_1_3_6_1_5_5_7_3_1=Dilysu Cleient Gwe TLS
+CertDumpEKU_1_3_6_1_5_5_7_3_2=Dilysu Cleient Gwe TLS
+CertDumpEKU_1_3_6_1_5_5_7_3_3=Llofnodi Cod
+CertDumpEKU_1_3_6_1_5_5_7_3_4=Diogelu e-bost
+CertDumpEKU_1_3_6_1_5_5_7_3_8=Stamp Amser
+CertDumpEKU_1_3_6_1_5_5_7_3_9=Llofnod OCSP
+CertDumpEKU_1_3_6_1_4_1_311_2_1_21=Microsoft Individual Code Signing
+CertDumpEKU_1_3_6_1_4_1_311_2_1_22=Microsoft Commercial Code Signing
+CertDumpEKU_1_3_6_1_4_1_311_10_3_1=Microsoft Trust List Signing
+CertDumpEKU_1_3_6_1_4_1_311_10_3_2=Microsoft Time Stamping
+CertDumpEKU_1_3_6_1_4_1_311_10_3_3=Microsoft Server Gated Crypto
+CertDumpEKU_1_3_6_1_4_1_311_10_3_4=Microsoft Encrypting File System
+CertDumpEKU_1_3_6_1_4_1_311_10_3_4_1=Microsoft File Recovery
+CertDumpEKU_1_3_6_1_4_1_311_10_3_5=Microsoft Windows Hardware Driver Verification
+CertDumpEKU_1_3_6_1_4_1_311_10_3_10=Microsoft Qualified Subordination
+CertDumpEKU_1_3_6_1_4_1_311_10_3_11=Microsoft Key Recovery
+CertDumpEKU_1_3_6_1_4_1_311_10_3_12=Microsoft Document Signing
+CertDumpEKU_1_3_6_1_4_1_311_10_3_13=Microsoft Lifetime Signing
+CertDumpEKU_1_3_6_1_4_1_311_20_2_2=Microsoft Smart Card Logon
+CertDumpEKU_1_3_6_1_4_1_311_21_6=Microsoft Key Recovery Agent
+CertDumpMSCerttype=Microsoft Certificate Template Name
+CertDumpMSNTPrincipal=Microsoft Principal Name
+CertDumpMSCAVersion=Fersiwn Microsoft CA
+CertDumpMSDomainGUID=Microsoft Domain GUID
+CertDumpEKU_2_16_840_1_113730_4_1=Netscape Server Gated Crypto
+CertDumpRFC822Name=Cyfeiriad E-bost
+CertDumpDNSName=Enw DNS
+CertDumpX400Address=Cyfeiriad X.400
+CertDumpDirectoryName=Enw X.500
+CertDumpEDIPartyName=Enw parti EDI
+CertDumpURI=URI
+CertDumpIPAddress=Cyfeiriad IP
+CertDumpRegisterID=OID cofrestredig
+CertDumpKeyID=Enw Allwedd
+CertDumpVerisignNotices=Negeseuon Defnyddwyr Verisign
+CertDumpUnused=Diddefnydd
+CertDumpKeyCompromise=Allwedd Cyfaddawd
+CertDumpCACompromise=Cyfaddawd CA
+CertDumpAffiliationChanged=Newid tadogaeth
+CertDumpSuperseded=Disodlwyd
+CertDumpCessation=Atal Gweithredu
+CertDumpHold=Dal Tystysgrif
+CertDumpOCSPResponder=OCSP
+CertDumpCAIssuers=Cyhoeddwyr CA
+CertDumpCPSPointer=Cyfeiriwr Certification Practice Statement
+CertDumpUserNotice=Rhybudd Defnyddiwr
+CertDumpLogotype=Logotype
+CertDumpECPublicKey=Allwedd Gyhoeddus Cromlin Eliptig
+CertDumpECDSAWithSHA1=Llofnod X9.62 ECDSA gyda SHA1
+CertDumpECprime192v1=Cromlin eliptig cysefin ANSI X9.62 192v1 (h.y. secp192r1, NIST P-192)
+CertDumpECprime192v2=Cromlin eliptig ANSI X9.62 prime192v2
+CertDumpECprime192v3=Cromlin eliptig ANSI X9.62 prime192v3
+CertDumpECprime239v1=Cromlin eliptig ANSI X9.62 prime239v1
+CertDumpECprime239v2=Cromlin eliptig ANSI X9.62 prime239v2
+CertDumpECprime239v3=Cromlin eliptig ANSI X9.62 prime239v3
+CertDumpECprime256v1=Cromlin eliptig ANSI X9.62 prime256v1 (aka secp256r1, NIST P-256)
+CertDumpECsecp112r1=Cromlin eliptig SECG secp112r1
+CertDumpECsecp112r2=Cromlin eliptig SECG secp112r2
+CertDumpECsecp128r1=Cromlin eliptig SECG secp128r1
+CertDumpECsecp128r2=Cromlin eliptig SECG secp128r2
+CertDumpECsecp160k1=Cromlin eliptig SECG secp160k1
+CertDumpECsecp160r1=Cromlin eliptig SECG secp160r1
+CertDumpECsecp160r2=Cromlin eliptig SECG secp160r2
+CertDumpECsecp192k1=Cromlin eliptig SECG secp192k1
+CertDumpECsecp224k1=Cromlin eliptig SECG secp224k1
+CertDumpECsecp224r1=Cromlin eliptig SECG secp224r1 (aka NIST P-224)
+CertDumpECsecp256k1=Cromlin eliptig SECG secp256k1
+CertDumpECsecp384r1=Cromlin eliptig SECG secp384r1 (aka NIST P-384)
+CertDumpECsecp521r1=Cromlin eliptig SECG secp521r1 (aka NIST P-521)
+CertDumpECc2pnb163v1=Cromlin eliptig ANSI X9.62 c2pnb163v1
+CertDumpECc2pnb163v2=Cromlin eliptig ANSI X9.62 c2pnb163v2
+CertDumpECc2pnb163v3=Cromlin eliptig ANSI X9.62c2pnb163v3
+CertDumpECc2pnb176v1=Cromlin eliptig ANSI X9.62 c2pnb176v1
+CertDumpECc2tnb191v1=Cromlin eliptig ANSI X9.62 c2tnb191v1
+CertDumpECc2tnb191v2=Cromlin eliptig ANSI X9.62 c2tnb191v2
+CertDumpECc2tnb191v3=Cromlin eliptig ANSI X9.62 c2tnb191v3
+CertDumpECc2onb191v4=Cromlin eliptig ANSI X9.62 c2onb191v4
+CertDumpECc2onb191v5=Cromlin eliptig ANSI X9.62 c2onb191v5
+CertDumpECc2pnb208w1=Cromlin eliptig ANSI X9.62 c2pnb208v1
+CertDumpECc2tnb239v1=Cromlin eliptig ANSI X9.62 c2tnb239v1
+CertDumpECc2tnb239v2=Cromlin eliptig ANSI X9.62 c2tnb239v2
+CertDumpECc2tnb239v3=Cromlin eliptig ANSI X9.62 c2tnb239v3
+CertDumpECc2onb239v4=Cromlin eliptig ANSI X9.62 c2onb239v4
+CertDumpECc2onb239v5=Cromlin eliptig ANSI X9.62 c2onb239v5
+CertDumpECc2pnb272w1=Cromlin eliptig ANSI X9.62 c2pnb272w1
+CertDumpECc2pnb304w1=Cromlin eliptig ANSI X9.62 c2pnb304w1
+CertDumpECc2tnb359v1=Cromlin eliptig ANSI X9.62 c2tnb359v1
+CertDumpECc2pnb368w1=Cromlin eliptig ANSI X9.62 c2pnb368w1
+CertDumpECc2tnb431r1=Cromlin eliptig ANSI X9.62 c2tnb431r1
+CertDumpECsect113r1=Cromlin eliptig SECG sect113r1
+CertDumpECsect113r2=Cromlin eliptig SECG sect113r2
+CertDumpECsect131r1=Cromlin eliptig SECG sect131r1
+CertDumpECsect131r2=Cromlin eliptig SECG sect131r2
+CertDumpECsect163k1=Cromlin eliptig SECG sect163k1 (aka NIST K-163)
+CertDumpECsect163r1=Cromlin eliptig SECG sect163r1
+CertDumpECsect163r2=Cromlin eliptig SECG sect163r2 (aka NIST B-163)
+CertDumpECsect193r1=Cromlin eliptig SECG sect193r1
+CertDumpECsect193r2=Cromlin eliptig SECG sect193r2
+CertDumpECsect233k1=Cromlin eliptig SECG sect233k1(aka NIST K-233)
+CertDumpECsect233r1=Cromlin eliptig SECG sect233r1 (aka NIST B-233)
+CertDumpECsect239k1=Cromlin eliptig SECG sect239k1
+CertDumpECsect283k1=Cromlin eliptig SECG sect283k1 (aka NIST K-283)
+CertDumpECsect283r1=Cromlin eliptig SECG sect283r1 (aka NIST B-283)
+CertDumpECsect409k1=Cromlin eliptig SECG sect409k1 (aka NIST K-409)
+CertDumpECsect409r1=Cromlin eliptig SECG sect409r1 (aka NIST B-409)
+CertDumpECsect571k1=Cromlin eliptig SECG sect571k1 (aka NIST K-571)
+CertDumpECsect571r1=Cromlin eliptig SECG sect571r1 (aka NIST B-571)
+CertDumpRawBytesHeader=Maint: %S Beit / %S Did
+AVATemplate=%S = %S
+
+PSMERR_SSL_Disabled=Methu cysylltu'n ddiogel oherwydd bod y protocol SSL wedi ei analluogi.
+PSMERR_SSL2_Disabled=Methu cysylltu'n ddiogel oherwydd bod y wefan'n defnyddio hen fersiwn anniogel o brotocol SSL.
+PSMERR_HostReusedIssuerSerial=Rydych wedi derbyn tystysgrif annilys.  Cysylltwch gweinyddwr y gweinydd neu gyfathrebwr e-bost a rhannu'r wybodaeth ganlynol:\n\nMae eich tystysgrif yn cynnwys yr un rhifau cyfresol a thystysgrif arall wedi ei gyhoeddi gan yr awdurdod tystysgrifau.  Defnyddiwch dystysgrif newydd yn cynnwys rhif cyfresol unigryw.
+
+# LOCALIZATION NOTE (SSLConnectionErrorPrefix2): %1$S is the host string, %2$S is more detailed information (localized as well).
+SSLConnectionErrorPrefix2=Digwyddodd gwall wrth gysylltu â %1$S. %2$S\n
+
+certErrorIntro=Mae %S yn defnyddio tystysgrif diogelwch annilys.
+
+certErrorTrust_SelfSigned=Nid oes modd ymddiried yn y dystysgrif am ei fod wedi ei hunanlofnodi.
+certErrorTrust_UnknownIssuer=Nid oes modd ymddiried yn y dystysgrif am nad yw ei chyhoeddwr yn hysbys.
+certErrorTrust_UnknownIssuer2=Efallai nad yw'r gweinydd yn anfon y tystysgrifau canolraddol priodol.
+certErrorTrust_UnknownIssuer3=Efallai bod angen mewnforio tystysgrif gwraidd ychwanegol.
+certErrorTrust_CaInvalid=Nid oes modd ymddiried yn y dystysgrif am ei fod wedi rhyddhau tystysgrif CA annilys.
+certErrorTrust_Issuer=Nid oes modd ymddiried yn y dystysgrif oherwydd nad oes modd ymddiried yn ei chyhoeddwr.
+certErrorTrust_SignatureAlgorithmDisabled=Nid oes ymddiriedaeth i'r dystysgrif gan ei fod wedi ei lofnodi gan ddefnyddio algorithm llofnod sydd wedi ei analluogi am nad yw'r algorithm yn anniogel.
+certErrorTrust_ExpiredIssuer=Nid oes modd ymddiried yn y dystysgrif oherwydd bod y dystysgrif ryddhau wedi dod i ben.
+certErrorTrust_Untrusted=Nid yw'r dystysgrif yn dod o fan gellir ymddiried ynddo.
+certErrorTrust_MitM=Mae eich cysylltiad yn cael ei ryngdorri gan ddirprwy TLS. Dadosodwch os yn bosib neu ffurfweddwch eich dyfais i ymddiried yn ei dystysgrif gwraidd.
+
+certErrorMismatch=Nid yw'r dystysgrif yn ddilys yn enw %S.
+# LOCALIZATION NOTE (certErrorMismatchSinglePrefix): %S is replaced by the domain for which the certificate is valid
+certErrorMismatchSinglePrefix=Dim ond ar gyfer %S mae'r dystysgrif yn ddilys.
+certErrorMismatchMultiple=Mae'r dystysgrif yn ddilys ar gyfer yr enwau canlynol yn unig:
+
+# LOCALIZATION NOTE (certErrorExpiredNow): Do not translate %1$S (date+time of expired certificate) or %2$S (current date+time)
+certErrorExpiredNow=Daeth y dystysgrif i ben ar %1$S. Yr amser cyfredol yw %2$S.
+
+# LOCALIZATION NOTE (certErrorNotYetValidNow): Do not translate %1$S (date+time certificate will become valid) or %2$S (current date+time)
+certErrorNotYetValidNow=Bydd y dystysgrif yn ddilys tan %1$S. Yr amser cyfredol yw %2$S.
+
+certErrorMitM=Mae gwefannau'n profi eu hunaniaeth drwy dystysgrifau, sy'n cael eu cyhoeddi gan awdurdodau tystysgrifau.
+# LOCALIZATION NOTE (certErrorMitM2): %S is brandShortName
+certErrorMitM2=Mae %S yn cael ei gefnogi gan Mozilla y corff dim-er-elw, sy'n gweinyddu storfa awdurdod tystysgrifau (CA) cwbl agored. Mae'r storfa'n cynorthwyo i sicrhau fod awdurdodau tystysgrif yn dilyn ymarfer gorau ar gyfer diogelwch defnyddwyr.
+# LOCALIZATION NOTE (certErrorMitM3): %S is brandShortName
+certErrorMitM3=Mae %S yn defnyddio storfa CA Mozilla i wirio bod cysylltiad yn ddiogel, yn hytrach na thystysgrifau wedi eu cyflenwi gan system weithredu'r defnyddiwr. Felly, os yw rhaglen gwrth-firws neu rwydwaith yn rhyng-gipio cysylltiad â thystysgrif diogelwch a gyhoeddwyd gan CA nad yw yn storfa CA Mozilla, mae'n ystyried bod y cysylltiad yn anniogel.
+
+certErrorSymantecDistrustAdministrator=Gallwch hysbysu gweinyddwr y wefan am y broblem hon.
+
+# LOCALIZATION NOTE (certErrorCodePrefix3): %S is replaced by the error code.
+certErrorCodePrefix3=Cod gwall: %S
+
+P12DefaultNickname=Tystysgrif wedi ei Fewnforio
+CertUnknown=Anhysbys
+CertNoEmailAddress=(dim cyfeiriad e-bost)
+CaCertExists=Mae'r dystysgrif wedi ei gosod fel awdurdod tystysgrif.
+NotACACert=Nid tystysgrif awdurdod tystysgrif yw hon, felly nid oes modd ei fewnforio i restr awdurdod tystysgrif.
+UserCertIgnoredNoPrivateKey=Nid oes modd gosod eich tystysgrif bersonol am nad chi yw perchennog yr allwedd breifat gyfatebol grëwyd pan ofynnwyd am y dystysgrif.
+UserCertImported=Mae eich tystysgrif bersonol wedi ei gosod. Dylech gadw copi wrth gefn ohoni.
+CertOrgUnknown=(Anhysbys)
+CertNotStored=(Heb ei Storio)
+CertExceptionPermanent=Parhaol
+CertExceptionTemporary=Dros dro
diff --git a/l10n-cy/security/manager/chrome/pippki/pippki.properties b/l10n-cy/security/manager/chrome/pippki/pippki.properties
new file mode 100644
index 0000000000..9f97b9fd30
--- /dev/null
+++ b/l10n-cy/security/manager/chrome/pippki/pippki.properties
@@ -0,0 +1,85 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Download Cert dialog
+# LOCALIZATION NOTE(newCAMessage1):
+# %S is a string representative of the certificate being downloaded/imported.
+newCAMessage1=Ydych chi eisiau ymddiried yn "%S" at y pwrpasau canlynol?
+unnamedCA=Awdurdod Tystysgrifo (dienw)
+
+getPKCS12FilePasswordMessage=Rhowch y cyfrinair ddefnyddiwyd i amgryptio'r ffeil tystysgrif wrth gefn:
+
+# Client auth
+clientAuthRemember=Cofio'r penderfyniad
+# LOCALIZATION NOTE(clientAuthNickAndSerial): Represents a single cert when the
+# user is choosing from a list of certificates.
+# %1$S is the nickname of the cert.
+# %2$S is the serial number of the cert in AA:BB:CC hex format.
+clientAuthNickAndSerial=%1$S [%2$S]
+# LOCALIZATION NOTE(clientAuthHostnameAndPort):
+# %1$S is the hostname of the server.
+# %2$S is the port of the server.
+clientAuthHostnameAndPort=%1$S:%2$S
+# LOCALIZATION NOTE(clientAuthMessage1): %S is the Organization of the server
+# cert.
+clientAuthMessage1=Corff: "%S"
+# LOCALIZATION NOTE(clientAuthMessage2): %S is the Organization of the issuer
+# cert of the server cert.
+clientAuthMessage2=Cyhoeddwyd o Dan: "%S"
+# LOCALIZATION NOTE(clientAuthIssuedTo): %1$S is the Distinguished Name of the
+# currently selected client cert, such as "CN=John Doe,OU=Example" (without
+# quotes).
+clientAuthIssuedTo=Cyhoeddwyd i: %1$S
+# LOCALIZATION NOTE(clientAuthSerial): %1$S is the serial number of the selected
+# cert in AA:BB:CC hex format.
+clientAuthSerial=Rhif cyfresol: %1$S
+# LOCALIZATION NOTE(clientAuthValidityPeriod):
+# %1$S is the already localized notBefore date of the selected cert.
+# %2$S is the already localized notAfter date of the selected cert.
+clientAuthValidityPeriod=Yn ddilys o %1$S hyd %2$S
+# LOCALIZATION NOTE(clientAuthKeyUsages): %1$S is a comma separated list of
+# already localized key usages the selected cert is valid for.
+clientAuthKeyUsages=Prif Ddefnydd: %1$S
+# LOCALIZATION NOTE(clientAuthEmailAddresses): %1$S is a comma separated list of
+# e-mail addresses the selected cert is valid for.
+clientAuthEmailAddresses=Cyfeiriadau e-bost: %1$S
+# LOCALIZATION NOTE(clientAuthIssuedBy): %1$S is the Distinguished Name of the
+# cert which issued the selected cert.
+clientAuthIssuedBy=Cyhoeddwyd gan: %1$S
+# LOCALIZATION NOTE(clientAuthStoredOn): %1$S is the name of the PKCS #11 token
+# the selected cert is stored on.
+clientAuthStoredOn=Storiwyd ar: %1$S
+
+# Page Info
+pageInfo_NoEncryption=Nid yw'r Cysylltiad wedi ei Amgryptio
+pageInfo_Privacy_None1=Nid yw gwefan %S yn cynnal amgryptiad ar gyfer y dudalen rydych yn ei darllen.
+pageInfo_Privacy_None2=Mae modd i bobl eraill ddarllen gwybodaeth sy'n cael ei hanfon ar draws y rhyngrwyd heb ei hamgryptio.\u0020 
+pageInfo_Privacy_None4=Nid yw'r dudalen rydych yn ei darllen wedi ei hamgryptio cyn cael ei gyrru ar draws y Rhyngrwyd.
+# LOCALIZATION NOTE (pageInfo_EncryptionWithBitsAndProtocol and pageInfo_BrokenEncryption):
+# %1$S is the name of the encryption standard,
+# %2$S is the key size of the cipher.
+# %3$S is protocol version like "SSL 3" or "TLS 1.2"
+pageInfo_EncryptionWithBitsAndProtocol=Mae'r Cysylltiad wedi ei Amgryptio (%1$S, allweddi did %2$S, %3$S)
+pageInfo_BrokenEncryption=Amgryptio wedi Torri (allweddi did %1$S, %2$S, %3$S)
+pageInfo_Privacy_Encrypted1=Roedd y dudalen rydych yn ei darllen wedi ei hamgryptio cyn cael ei gyrru ar draws y Rhyngrwyd.
+pageInfo_Privacy_Encrypted2=Mae amgryptio yn ei gwneud hi'n anodd iawn i bobl sydd heb eu hawdurdodi i ddarllen gwybodaeth sy'n teithio rhwng cyfrifiaduron. Mae felly'n annhebygol iawn bod unrhyw un wedi darllen y dudalen hon wrth iddi deithio ar draws y rhwydwaith.
+pageInfo_MixedContent=Cysylltiad wedi ei Amgryptio'n Rhannol
+pageInfo_MixedContent2=Nid oedd rhannau o'r dudalen wedi eu hamgryptio cyn eu hanfon dros y Rhyngrwyd.
+pageInfo_WeakCipher=Gall bobl eraill weld eich gwybodaeth neu newid ymddygiad y wefan. Gall bobl eraill weld eich gwybodaeth neu newid ymddygiad y wefan.
+pageInfo_CertificateTransparency_Compliant=Mae'r wefan hon yn cyd-fynd â'r dystysgrif Polisi Tryloyw.
+
+# Token Manager
+password_not_set=(heb ei osod)
+failed_pw_change=Methu newid y Prif Gyfrinair.
+incorrect_pw=Wedi rhoi cyfrinair anghywir. Ceisiwch eto.
+pw_change_ok=Newidiwyd y Prif Gyfrinair yn llwyddiannus.
+pw_erased_ok=Rhybudd! Rydych wedi dileu eich Prif Gyfrinair.\u0020 
+pw_not_wanted=Rhybudd! Rydych wedi penderfynu peidio defnyddio Prif Gyfrinair.
+pw_empty_warning=Ni fydd eich cyfrineiriau gwe ac e-bost, data ffurflen, nag eich allweddi preifat yn cael eu hamddiffyn.
+pw_change2empty_in_fips_mode=Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+enable_fips=Galluogi FIPS
+
+resetPasswordConfirmationTitle=Ailosod Prif Gyfrinair
+resetPasswordConfirmationMessage=Mae eich cyfrinair wedi cael ei ail osod.
+
diff --git a/l10n-cy/security/manager/security/certificates/certManager.ftl b/l10n-cy/security/manager/security/certificates/certManager.ftl
new file mode 100644
index 0000000000..e9a0068029
--- /dev/null
+++ b/l10n-cy/security/manager/security/certificates/certManager.ftl
@@ -0,0 +1,251 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+certmgr-title =
+    .title = Rheolwr Tystysgrifau
+certmgr-tab-mine =
+    .label = Eich Tystysgrifau
+certmgr-tab-remembered =
+    .label = Penderfyniadau Dilysu
+certmgr-tab-people =
+    .label = Pobl
+certmgr-tab-servers =
+    .label = Gweinyddion
+certmgr-tab-ca =
+    .label = Awdurdodau
+certmgr-mine = Mae gennych dystysgrifau gan y cyrff hyn sy'n eich adnabod chi
+certmgr-remembered = Mae'r tystysgrifau hyn yn cael eu defnyddio i'ch adnabod chi ar wefannau
+certmgr-people = Mae gennych dystysgrifau ar ffeil sy'n adnabod y bobl hyn
+certmgr-servers = Mae gennych dystysgrifau ar ffeil sy'n adnabod y bobl hyn
+certmgr-server = Mae'r cofnodion hyn yn nodi eithriadau gwall tystysgrif gweinydd
+certmgr-ca = Mae gennych dystysgrifau ar ffeil sy'n adnabod yr awdurdodau tystysgrif
+certmgr-detail-general-tab-title =
+    .label = Cyffredinol
+    .accesskey = C
+certmgr-detail-pretty-print-tab-title =
+    .label = Manylion
+    .accesskey = M
+certmgr-pending-label =
+    .value = Wrthi'n dilysu'r dystysgrif…
+certmgr-subject-label = Dynodwyd i
+certmgr-issuer-label = Cyhoeddwyd gan
+certmgr-period-of-validity = Cyfnod Dilysrwydd
+certmgr-fingerprints = Olion Bysedd
+certmgr-cert-detail =
+    .title = Manylion Tystysgrif
+    .buttonlabelaccept = Cau
+    .buttonaccesskeyaccept = C
+certmgr-cert-detail-commonname = Enw Cyffredin (CN)
+certmgr-cert-detail-org = Corff (O)
+certmgr-cert-detail-orgunit = Uned Corff (OU)
+certmgr-cert-detail-serial-number = Rhif Cyfresol
+certmgr-cert-detail-sha-256-fingerprint = Ôl bys SHA-256
+certmgr-cert-detail-sha-1-fingerprint = Ôl bys SHA1
+certmgr-edit-ca-cert =
+    .title = Golygu gosodiadau ymddiried tystysgrif CA
+    .style = width: 48em;
+certmgr-edit-cert-edit-trust = Golygu gosodiadau ymddiried:
+certmgr-edit-cert-trust-ssl =
+    .label = Mae'r dystysgrif yn medru adnabod gwefannau.
+certmgr-edit-cert-trust-email =
+    .label = Mae'r dystysgrif yn medru adnabod defnyddwyr e-bost.
+certmgr-delete-cert =
+    .title = Dileu Tystysgrif
+    .style = width: 48em; height: 24em;
+certmgr-cert-host =
+    .label = Gwesteiwr
+certmgr-cert-name =
+    .label = Enw'r Dystysgrif
+certmgr-cert-server =
+    .label = Gweinydd
+certmgr-override-lifetime =
+    .label = Hyd Oes
+certmgr-token-name =
+    .label = Dyfais Diogelwch
+certmgr-begins-on = Cychwyn ar
+certmgr-begins-label =
+    .label = Cychwyn ar
+certmgr-expires-on = Daw i ben ar
+certmgr-expires-label =
+    .label = Daw i ben ar
+certmgr-email =
+    .label = Cyfeiriad E-bost
+certmgr-serial =
+    .label = Rhif Cyfresol
+certmgr-view =
+    .label = Golwg…
+    .accesskey = G
+certmgr-edit =
+    .label = Golygu'r Ymddiriedaeth…
+    .accesskey = Y
+certmgr-export =
+    .label = Allforio…
+    .accesskey = A
+certmgr-delete =
+    .label = Dileu…
+    .accesskey = D
+certmgr-delete-builtin =
+    .label = Dileu neu Ddrwgdybio…
+    .accesskey = i
+certmgr-backup =
+    .label = Wrth Gefn…
+    .accesskey = W
+certmgr-backup-all =
+    .label = Popeth Wrth Gefn…
+    .accesskey = P
+certmgr-restore =
+    .label = Mewnforio…
+    .accesskey = M
+certmgr-details =
+    .value = Meysydd Tystysgrif
+    .accesskey = T
+certmgr-fields =
+    .value = Gwerth Maes
+    .accesskey = G
+certmgr-hierarchy =
+    .value = Hierarchaeth Tystysgrifau
+    .accesskey = H
+certmgr-add-exception =
+    .label = Ychwanegu Eithriad…
+    .accesskey = Y
+exception-mgr =
+    .title = Ychwanegu Eithriad Diogelwch
+exception-mgr-extra-button =
+    .label = Cadarnhau Eithriad Diogelwch
+    .accesskey = C
+exception-mgr-supplemental-warning = Ni fydd banciau, siopau a gwefannau cyhoeddus yn gofyn i chi wneud hyn.
+exception-mgr-cert-location-url =
+    .value = Lleoliad:
+exception-mgr-cert-location-download =
+    .label = Estyn Tystysgrif
+    .accesskey = G
+exception-mgr-cert-status-view-cert =
+    .label = Golwg…
+    .accesskey = G
+exception-mgr-permanent =
+    .label = Cadw'r estyniad yn barhaol
+    .accesskey = C
+pk11-bad-password = Cyfrinair yn anghywir.
+pkcs12-decode-err = Methu dadgodio'r ffeil.  Un ai nid yw mewn fformat PKCS#12, neu mae wedi ei lygru, neu roedd eich cyfrinair yn anghywir.
+pkcs12-unknown-err-restore = Methwyd ag adfer ffeil PKCS#12 am resymau anhysbys.
+pkcs12-unknown-err-backup = Methwyd â gwneud copi wrth gefn o'r ffeil PKCS#12 am resymau anhysbys.
+pkcs12-unknown-err = Methodd gweithrediad PKCS #12 am reswm anhysbys.
+pkcs12-info-no-smartcard-backup = Nid yw'n bosibl cadw tystysgrif wrth gefn o ddyfeisiadau caledwedd diogelwch megis cerdyn cof.
+pkcs12-dup-data = Mae'r dystysgrif a'r allwedd breifat yn bodoli eisoes ar y ddyfais diogelwch.
+
+## PKCS#12 file dialogs
+
+choose-p12-backup-file-dialog = Enw Ffeil i'w Gadw wrth Gefn
+file-browse-pkcs12-spec = Ffeiliau PKCS12
+choose-p12-restore-file-dialog = Ffeil Tystysgrif i'w Mewnforio
+
+## Import certificate(s) file dialog
+
+file-browse-certificate-spec = Ffeiliau Tystysgrif
+import-ca-certs-prompt = Dewis Ffeil yn cynnwys tystysgrif(au) CA i'w mewnforio
+import-email-cert-prompt = Dewis Ffeil yn cynnwys tystysgrif e-bost rhywun i'w fewnforio
+
+## For editing certificates trust
+
+# Variables:
+#   $certName: the name of certificate
+edit-trust-ca = Mae Tystysgrif "{ $certName }" yn cynrychioli Awdurdod Tystysgrifo.
+
+## For Deleting Certificates
+
+delete-user-cert-title =
+    .title = Dileu eich Tystysgrifau
+delete-user-cert-confirm = Ydych chi'n siŵr eich bod eisiau dileu'r tystysgrifau hyn?
+delete-user-cert-impact = Os byddwch yn dileu un o'ch tystysgrifau eich hun, nid oes modd ei ddefnyddio i adnabod eich hun.
+delete-ssl-cert-title =
+    .title = Dileu Eithriadau Tystysgrif Gweinydd
+delete-ssl-cert-confirm = Ydych chi'n siŵr eich bod eisiau dileu eithriadau'r gweinydd?
+delete-ssl-cert-impact = Os ydych yn dileu eithriad gweinydd, gallwch adfer gwirio diogelwch y gweinydd a disgwyl iddo ddefnyddio tystysgrif ddilys.
+delete-ssl-override-title =
+    .title = Dileu Eithriad Tystysgrif Gweinydd
+delete-ssl-override-confirm = Ydych chi'n siŵr eich bod eisiau dileu eithriadau'r gweinydd?
+delete-ssl-override-impact = Os ydych yn dileu eithriad gweinydd, gallwch adfer gwirio diogelwch y gweinydd a disgwyl iddo ddefnyddio tystysgrif ddilys.
+delete-ca-cert-title =
+    .title = Dileu neu Ddadymddiried Tystysgrifau CA
+delete-ca-cert-confirm = Rydych wedi gofyn i gael dileu'r tystysgrifau TA hyn. Ar gyfer tystysgrifau mewnol bydd yr ymddiriedaeth yn cael ei dynnu, sydd a'r un effaith. Ydych chi'n siŵr eich bod eisiau dileu neu dad-ymddiried?
+delete-ca-cert-impact = Os fyddwch yn dileu neu dad-ymddiried tystysgrif awdurdod tystysgrifo (CA), ni fydd y rhaglen yn ymddiried unrhyw dystysgrif sy'n cael ei chyhoeddi gan y CA.
+delete-email-cert-title =
+    .title = Dileu Tystysgrifau E-bost
+delete-email-cert-confirm = Ydych chi'n siŵr eich bod eisiau dileu tystysgrifau e-bost y bobl hyn?
+delete-email-cert-impact = Os fyddwch yn dileu tystysgrif e-bost y person, ni fyddwch yn gallu anfon e-byst amgryptiedig at y person hwnnw.
+# Used for semi-uniquely representing a cert.
+#
+# Variables:
+#   $serialNumber : the serial number of the cert in AA:BB:CC hex format.
+cert-with-serial =
+    .value = Tystysgrif gyda rhif cyfresol : { $serialNumber }
+
+## Cert Viewer
+
+# Title used for the Certificate Viewer.
+#
+# Variables:
+#   $certificate : a string representative of the certificate being viewed.
+cert-viewer-title =
+    .title = Darllenwr Tystysgrif: “{ $certName }”
+not-present =
+    .value = <Nid yw'n Rhan o'r Dystysgrif>
+# Cert verification
+cert-verified = Nid yw'r dystysgrif wedi cael ei gwirio ar gyfer y defnydd canlynol:
+# Add usage
+verify-ssl-client =
+    .value = Tystysgrif Cleient SSL
+verify-ssl-server =
+    .value = Tystysgrif Gwasanaethwr SSL
+verify-ssl-ca =
+    .value = Awdurdod Tystysgrif SSL
+verify-email-signer =
+    .value = Tystysgrif Llofnodwr E-bost
+verify-email-recip =
+    .value = Tystysgrif Derbynnydd E-bost
+# Cert verification
+cert-not-verified-cert-revoked = Nid oedd modd gwirio'r dystysgrif am ei bod wedi ei diddymu.
+cert-not-verified-cert-expired = Methu gwirio'r dystysgrif am ei bod wedi dod i ben.
+cert-not-verified-cert-not-trusted = Does dim modd gwirio'r dystysgrif am nad oes modd ymddiried ynddi.
+cert-not-verified-issuer-not-trusted = Does dim modd gwirio'r dystysgrif am nad oes modd ymddiried yn y cyhoeddwr.
+cert-not-verified-issuer-unknown = Nid oedd modd gwirio'r dystysgrif am fod y cyhoeddwr yn anhysbys.
+cert-not-verified-ca-invalid = Methu gwirio'r dystysgrif oherwydd bod tystysgrif yr awdurdod tystysgrifo yn annilys.
+cert-not-verified_algorithm-disabled = Nid oes modd dilysu'r dystysgrif gan ei fod wedi ei lofnodi gan ddefnyddio algorithm llofnod sydd wedi ei analluogi am nad yw'r algorithm yn anniogel.
+cert-not-verified-unknown = Nid oedd modd gwirio'r dystysgrif am resymau anhysbys.
+# Used to indicate that the user chose not to send a client authentication certificate to a server that requested one in a TLS handshake.
+send-no-client-certificate = Anfonwyd dim tystysgrif cleient
+# Used when no cert is stored for an override
+no-cert-stored-for-override = (Heb ei Storio)
+
+## Used to show whether an override is temporary or permanent
+
+permanent-override = Parhaol
+temporary-override = Dros dro
+
+## Add Security Exception dialog
+
+add-exception-branded-warning = Rydych ar fin atal y ffordd mae { -brand-short-name } yn adnabod y wefan.
+add-exception-invalid-header = Mae'r wefan yn ceisio dweud pwy ydyw gyda gwybodaeth annilys.
+add-exception-domain-mismatch-short = Gwefan Anghywir
+add-exception-domain-mismatch-long = Mae'r dystysgrif yn perthyn i wefan gwahanol, sy'n golygu y gall rhywun fod yn efelychu'r wefan hon.
+add-exception-expired-short = Hen Wybodaeth
+add-exception-expired-long = Nid yw'r dystysgrif yn ddilys ar hyn o bryd. Gall ei fod wedi cael ei ddwyn neu ei golli, a gall fod yn cael ei ddefnyddio i ymddangos fel y wefan hon.
+add-exception-unverified-or-bad-signature-short = Hunaniaeth Anhysbys
+add-exception-unverified-or-bad-signature-long = Methu ymddiried yn y dystysgrif am nad yw wedi ei ddilysu gan awdurdod hysbys sy'n defnyddio llofnod diogel.
+add-exception-valid-short = Tystysgrif Dilys
+add-exception-valid-long = Mae'r wefan yn darparu gwybodaeth ddilys amdani ei hun.  Nid oes angen gosod eithriad.
+add-exception-checking-short = Gwirio Gwybodaeth
+add-exception-checking-long = Ceisio adnabod y wefan…
+add-exception-no-cert-short = Dim Gwybodaeth ar Gael
+add-exception-no-cert-long = Methu canfod statws dynodiad ar gyfer y wefan hon.
+
+## Certificate export "Save as" and error dialogs
+
+save-cert-as = Cadw Tystysgrif i Ffeil
+cert-format-base64 = Tystysgrif X.509 (PEM)
+cert-format-base64-chain = Tystysgrif X.509gyda chadwyn (PEM)
+cert-format-der = Tystysgrif X.509 (DER)
+cert-format-pkcs7 = Tystysgrif X.509 (PKCS#7)
+cert-format-pkcs7-chain = Tystysgrif X.509 gyda chadwyn (PKCS#7)
+write-file-failure = Gwall Ffeil
diff --git a/l10n-cy/security/manager/security/certificates/deviceManager.ftl b/l10n-cy/security/manager/security/certificates/deviceManager.ftl
new file mode 100644
index 0000000000..ff16d3b525
--- /dev/null
+++ b/l10n-cy/security/manager/security/certificates/deviceManager.ftl
@@ -0,0 +1,135 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Strings used for device manager
+
+devmgr =
+    .title = Rheolwr Dyfeisiadau
+    .style = width: 67em; height: 32em;
+
+devmgr-devlist =
+    .label = Modiwlau a Dyfeisiadau Diogelwch
+
+devmgr-header-details =
+    .label = Manylion
+
+devmgr-header-value =
+    .label = Gwerth
+
+devmgr-button-login =
+    .label = Mewngofnodi
+    .accesskey = M
+
+devmgr-button-logout =
+    .label = Allgofnodi
+    .accesskey = A
+
+devmgr-button-changepw =
+    .label = Newid Cyfrinair
+    .accesskey = N
+
+devmgr-button-load =
+    .label = Llwytho
+    .accesskey = L
+
+devmgr-button-unload =
+    .label = Dadlwytho
+    .accesskey = D
+
+devmgr-button-enable-fips =
+    .label = Galluogi FIPS
+    .accesskey = F
+
+devmgr-button-disable-fips =
+    .label = Analluogi FIPS
+    .accesskey = F
+
+## Strings used for load device
+
+load-device =
+    .title = Llwytho Gyrrwr Dyfais PKCS#11
+
+load-device-info = Rhoi gwybodaeth am y modiwl rydych eisiau ei ychwanegu.
+
+load-device-modname =
+    .value = Enw Modiwl
+    .accesskey = M
+
+load-device-modname-default =
+    .value = Modiwl newydd PKCS#11
+
+load-device-filename =
+    .value = Enw ffeil modiwl
+    .accesskey = E
+
+load-device-browse =
+    .label = Pori…
+    .accesskey = P
+
+## Token Manager
+
+devinfo-status =
+    .label = Statws
+
+devinfo-status-disabled =
+    .label = Analluogwyd
+
+devinfo-status-not-present =
+    .label = Ddim yn Bresennol
+
+devinfo-status-uninitialized =
+    .label = Heb gychwyn
+
+devinfo-status-not-logged-in =
+    .label = Heb Fewngofnodi
+
+devinfo-status-logged-in =
+    .label = Wedi mewngofnodi
+
+devinfo-status-ready =
+    .label = Parod
+
+devinfo-desc =
+    .label = Disgrifiad
+
+devinfo-man-id =
+    .label = Gwneuthurwr
+
+devinfo-hwversion =
+    .label = Fersiwn HW
+devinfo-fwversion =
+    .label = Fersiwn FW
+
+devinfo-modname =
+    .label = Modiwl
+
+devinfo-modpath =
+    .label = Llwybr
+
+login-failed = Wedi methu Mewngofnodi
+
+devinfo-label =
+    .label = Label
+
+devinfo-serialnum =
+    .label = Rhif Cyfresol
+
+fips-nonempty-password-required = Mae modd FIPS yn gofyn i chi gael Prif Gyfrinair wedi ei osod ar gyfer pob dyfais diogelwch. Rhowch gyfrinair cyn ceisio cychwyn modd FIPS.
+
+fips-nonempty-primary-password-required = Mae modd FIPS yn gofyn i chi gael Prif Gyfrinair wedi ei osod ar gyfer pob dyfais diogelwch. Rhowch gyfrinair cyn ceisio cychwyn modd FIPS.
+unable-to-toggle-fips = Methu newid modd FIPS ar gyfer y ddyfais diogelwch. Argymhellir eich bod yn gadael y rhaglen a'i hailgychwyn.
+load-pk11-module-file-picker-title = Dewis gyrrwr dyfais PKCS#11 i'w lwytho
+
+# Load Module Dialog
+load-module-help-empty-module-name =
+    .value = Nid oes modd i'r enw modiwl fod yn wag.
+
+# Do not translate 'Root Certs'
+load-module-help-root-certs-module-name =
+    .value = Mae ‘Root Certs‘ ar gadw ac nid oes modd ei ddefnyddio fel enw modiwl.
+
+add-module-failure = Methu ychwanegu modiwl
+del-module-warning = Ydych chi'n siŵr eich bod eisiau dileu'r modiwl diogelwch?
+del-module-error = Methu dileu modiwl
diff --git a/l10n-cy/security/manager/security/pippki/pippki.ftl b/l10n-cy/security/manager/security/pippki/pippki.ftl
new file mode 100644
index 0000000000..590b2a0ec7
--- /dev/null
+++ b/l10n-cy/security/manager/security/pippki/pippki.ftl
@@ -0,0 +1,91 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+password-quality-meter = Mesurydd ansawdd y cyfrinair
+
+## Change Password dialog
+
+change-password-window =
+    .title = Newid Prif Gyfrinair
+
+change-device-password-window =
+    .title = Newid Cyfrinair
+
+# Variables:
+# $tokenName (String) - Security device of the change password dialog
+change-password-token = Dyfais Diogelwch: { $tokenName }
+change-password-old = Cyfrinair cyfredol:
+change-password-new = Cyfrinair newydd:
+change-password-reenter = Y cyfrinair newydd (eto):
+
+## Reset Password dialog
+
+reset-password-window =
+    .title = Ailosod Prif Gyfrinair
+    .style = width: 40em
+
+pippki-failed-pw-change = Methu newid cyfrinair.
+pippki-incorrect-pw = Wedi rhoi cyfrinair anghywir. Ceisiwch eto.
+pippki-pw-change-ok = Mae'r cyfrinair wedi ei newid yn llwyddiannus.
+
+pippki-pw-empty-warning = Fydd eich cyfrineiriau a'ch allweddi preifat wedi'u storio ddim yn cael eu gwarchod.
+pippki-pw-erased-ok = Rydych wedi dileu eich Prif Gyfrinair. { pippki-pw-empty-warning }
+pippki-pw-not-wanted = Rhybudd! Rydych wedi penderfynu peidio defnyddio Prif Gyfrinair. { pippki-pw-empty-warning }
+
+pippki-pw-change2empty-in-fips-mode = Rydych ym modd FIPS. Mae FIPS angen gyfrinair nad yw'n wag.
+
+## Reset Primary Password dialog
+
+reset-primary-password-window =
+    .title = Ailosod Prif Gyfrinair
+    .style = width: 40em
+reset-password-button-label =
+    .label = Ailosod
+reset-password-text = Os byddwch yn ailosod eich prif gyfrinair, bydd eich cyfrineiriau gwe ac e-bost, data ffurflen, tystysgrifau personol ac allweddi preifat sydd wedi eu cadw'n cael eu colli. Ydych chi'n siŵr eich bod eisiau ailosod eich prif gyfrinair?
+
+reset-primary-password-text = Os byddwch yn ailosod eich Prif Gyfrinair, bydd eich cyfrineiriau gwe ac e-bost, data ffurflen, tystysgrifau personol ac allweddi preifat sydd wedi eu cadw'n cael eu colli. Ydych chi'n siŵr eich bod eisiau ailosod eich Prif Gyfrinair?
+
+pippki-reset-password-confirmation-title = Ailosod Prif Gyfrinair
+pippki-reset-password-confirmation-message = Mae eich Prif Gyfrinair wedi cael ei ail osod.
+
+## Downloading cert dialog
+
+download-cert-window =
+    .title = Llwytho Tystysgrifau i Lawr
+    .style = width: 46em
+download-cert-message = Rydych wedi cael cais i ymddiried mewn Awdurdod Tystysgrifo (CA) newydd.
+download-cert-trust-ssl =
+    .label = Ymddiried yn yr Awdurdod Tystysgrifo i adnabod gwefannau.
+download-cert-trust-email =
+    .label = Ymddiried yn yr Awdurdod Tystysgrifo i adnabod defnyddwyr e-bost.
+download-cert-message-desc = Cyn ymddiried mewn Awdurdod Tystysgrifo at unrhyw bwrpas, dylech archwilio ei dystysgrif a'i bolisi a chanllawiau (os yw ar gael).
+download-cert-view-cert =
+    .label = Golwg
+download-cert-view-text = Archwilio tystysgrif Awdurdod Tystysgrifo
+
+## Client Authorization Ask dialog
+
+client-auth-window =
+    .title = Cais am Adnabod Defnyddiwr
+client-auth-site-description = Mae'r wefan yn gofyn i chi ddweud pwy ydych gyda thystysgrif diogelwch:
+client-auth-choose-cert = Dewiswch dystysgrif i'w chyflwyno fel adnabyddiaeth:
+client-auth-cert-details = Manylion y dystysgrif hon:
+
+## Set password (p12) dialog
+
+set-password-window =
+    .title = Dewiswch Gyfrinair Tystysgrif wrth Gefn
+set-password-message = Bydd y cyfrinair tystysgrif wrth gefn yma'n amddiffyn y ffeil wrth gefn rydych ar fin ei greu.  Rhaid gosod y cyfrinair i barhau gyda'r ffeil wrth gefn.
+set-password-backup-pw =
+    .value = Cyfrinair y dystysgrif wrth gefn:
+set-password-repeat-backup-pw =
+    .value = Cyfrinair y dystysgrif wrth gefn (eto):
+set-password-reminder = Pwysig: Os byddwch yn anghofio eich cyfrinair diogelwch cludadwy, ni fydd modd i chi adfer y ffeil wrth gefn yma eto.  Cofnodwch hwn mewn man diogel.
+
+## Protected Auth dialog
+
+protected-auth-window =
+    .title = Dilysu Tocyn Diogel
+protected-auth-msg = Dilyswch i'r tocyn. Mae dulliau dilysu'n dibynnu ar y math o docyn.
+protected-auth-token = Tocyn:
diff --git a/l10n-cy/services/sync/sync.properties b/l10n-cy/services/sync/sync.properties
new file mode 100644
index 0000000000..b0dbc8acd5
--- /dev/null
+++ b/l10n-cy/services/sync/sync.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# %1: the user name (Ed), %2: the app name (Firefox), %3: the operating system (Android)
+client.name2 = %1$S's %2$S ar %3$S
+
+# %S is the date and time at which the last sync successfully completed
+lastSync2.label = Cydweddiad diwethaf: %S
+
+# signInToSync.description is the tooltip for the Sync buttons when Sync is
+# not configured.
+signInToSync.description = Mewngofnodwch i Sync
+
diff --git a/l10n-cy/toolkit/chrome/alerts/alert.dtd b/l10n-cy/toolkit/chrome/alerts/alert.dtd
new file mode 100644
index 0000000000..da0e9dd2d8
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/alerts/alert.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY     closeAlert.tooltip          "Cau'r hysbysiad">
+<!ENTITY     settings.label              "Gosodiadau">
diff --git a/l10n-cy/toolkit/chrome/alerts/alert.properties b/l10n-cy/toolkit/chrome/alerts/alert.properties
new file mode 100644
index 0000000000..c1715f4ee6
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/alerts/alert.properties
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE(closeButton.title): Used as the close button text for web notifications on OS X.
+# This should ideally match the string that OS X uses for the close button on alert-type
+# notifications. OS X will truncate the value if it's too long.
+closeButton.title = Cau
+# LOCALIZATION NOTE(actionButton.label): Used as the button label to provide more actions on OS X notifications. OS X will truncate this if it's too long.
+actionButton.label = …
+# LOCALIZATION NOTE(webActions.disableForOrigin.label): %S is replaced
+# with the hostname origin of the notification.
+webActions.disableForOrigin.label = Analluogi hysbysiadau o %S
+
+# LOCALIZATION NOTE(source.label): Used to show the URL of the site that
+# sent the notification (e.g., "via mozilla.org"). "%1$S" is the source host
+# and port.
+source.label=drwy %1$S
+webActions.settings.label = Gosodiadau hysbysiadau
+
+# LOCALIZATION NOTE(pauseNotifications.label): %S is replaced with the
+# brandShortName of the application.
+pauseNotifications.label = Oedi hysbysiadau nes i %S ailgychwyn
diff --git a/l10n-cy/toolkit/chrome/autoconfig/autoconfig.properties b/l10n-cy/toolkit/chrome/autoconfig/autoconfig.properties
new file mode 100644
index 0000000000..664315eab2
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/autoconfig/autoconfig.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+readConfigTitle = Gwall Ffurfweddiad
+readConfigMsg = Methwyd darllen y ffeil ffurfweddiad. Cysylltwch â'ch gweinyddwr system.
+
+autoConfigTitle = Rhybudd AutoConfig
+autoConfigMsg = Methodd Netscape.cfg/AutoConfig. Cysylltwch â'ch gweinyddwr system.\n Gwall: methodd %S:
+
+emailPromptTitle = Cyfeiriad E-bost
+emailPromptMsg = Rhowch eich cyfeiriad e-bost
diff --git a/l10n-cy/toolkit/chrome/global-platform/mac/intl.properties b/l10n-cy/toolkit/chrome/global-platform/mac/intl.properties
new file mode 100644
index 0000000000..71265a9ef1
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/mac/intl.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (intl.ellipsis): Use the unicode ellipsis char, \u2026,
+# or use "..." if \u2026 doesn't suit traditions in your locale.
+intl.ellipsis=…
diff --git a/l10n-cy/toolkit/chrome/global-platform/mac/platformKeys.properties b/l10n-cy/toolkit/chrome/global-platform/mac/platformKeys.properties
new file mode 100644
index 0000000000..e1ce2fd906
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/mac/platformKeys.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#mac
+#this file defines the on screen display names for the various modifier keys
+#these are used in XP menus to show keyboard shortcuts
+
+# Platform: Mac
+# This file defines the on-screen display names for the various modifier keys
+# and the Return key (VK_RETURN).
+# These are used in XP menus to show keyboard shortcuts.
+
+# The Shift key - open up arrow symbol (ctrl-e)
+VK_SHIFT=⇧
+
+# The Command key - clover leaf symbol (ctrl-q)
+VK_META=⌘
+
+# The Win key - never generated by native key event
+VK_WIN=win
+
+# The Option/Alt key - splitting tracks symbol (ctrl-g)
+VK_ALT=⌥
+
+# The Control key - hat symbol (ctrl-f)
+VK_CONTROL=⌃
+
+# The Return key (on the main keyboard or numpad):
+# "Enter" on Windows/Unix, "Return" on Mac
+VK_RETURN=Return
+
+# The separator character used between modifiers (none on Mac OS)
+MODIFIER_SEPARATOR=
diff --git a/l10n-cy/toolkit/chrome/global-platform/unix/intl.properties b/l10n-cy/toolkit/chrome/global-platform/unix/intl.properties
new file mode 100644
index 0000000000..71265a9ef1
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/unix/intl.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (intl.ellipsis): Use the unicode ellipsis char, \u2026,
+# or use "..." if \u2026 doesn't suit traditions in your locale.
+intl.ellipsis=…
diff --git a/l10n-cy/toolkit/chrome/global-platform/unix/platformKeys.properties b/l10n-cy/toolkit/chrome/global-platform/unix/platformKeys.properties
new file mode 100644
index 0000000000..28e77ecaa5
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/unix/platformKeys.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#default
+#this file defines the on screen display names for the various modifier keys
+#these are used in XP menus to show keyboard shortcuts
+
+# Platform: Unix
+# This file defines the on-screen display names for the various modifier keys
+# and the Enter key (VK_RETURN).
+# These are used in XP menus to show keyboard shortcuts.
+
+# The Shift key
+VK_SHIFT=Shift
+
+# The Command key
+VK_META=Meta
+
+# The Win key (Super key and Hyper keys are mapped to DOM Win key)
+VK_WIN=Win
+
+# The Alt key
+VK_ALT=Alt
+
+# The Control key
+VK_CONTROL=Ctrl
+
+# The Enter key (on the main keyboard or numpad):
+# "Enter" on Windows/Unix, "Return" on Mac
+VK_RETURN=Enter
+
+# The separator character used between modifiers
+MODIFIER_SEPARATOR=+
diff --git a/l10n-cy/toolkit/chrome/global-platform/win/intl.properties b/l10n-cy/toolkit/chrome/global-platform/win/intl.properties
new file mode 100644
index 0000000000..71265a9ef1
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/win/intl.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (intl.ellipsis): Use the unicode ellipsis char, \u2026,
+# or use "..." if \u2026 doesn't suit traditions in your locale.
+intl.ellipsis=…
diff --git a/l10n-cy/toolkit/chrome/global-platform/win/platformKeys.properties b/l10n-cy/toolkit/chrome/global-platform/win/platformKeys.properties
new file mode 100644
index 0000000000..2d0dd84b95
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/win/platformKeys.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#default
+#this file defines the on screen display names for the various modifier keys
+#these are used in XP menus to show keyboard shortcuts
+
+# Platform: Windows
+# This file defines the on-screen display names for the various modifier keys
+# and the Enter key (VK_RETURN).
+# These are used in XP menus to show keyboard shortcuts.
+
+# The Shift key
+VK_SHIFT=Shift
+
+# The Command key
+VK_META=Meta
+
+# The Win key
+VK_WIN=Win
+
+# The Alt key
+VK_ALT=Alt
+
+# The Control key
+VK_CONTROL=Ctrl
+
+# The Enter key (on the main keyboard or numpad):
+# "Enter" on Windows/Unix, "Return" on Mac
+VK_RETURN=Enter
+
+# The separator character used between modifiers
+MODIFIER_SEPARATOR=+
diff --git a/l10n-cy/toolkit/chrome/global/aboutReader.properties b/l10n-cy/toolkit/chrome/global/aboutReader.properties
new file mode 100644
index 0000000000..9d2a7d9dc0
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/aboutReader.properties
@@ -0,0 +1,66 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#LOCALIZATION NOTE (aboutReader.loading2):
+# Use the unicode ellipsis char, \u2026,
+# or use "..." if \u2026 doesn't suit traditions in your locale.
+aboutReader.loading2=Llwytho…
+aboutReader.loadError=Methwyd llwytho erthygl o dudalen
+
+aboutReader.colorScheme.light=Golau
+aboutReader.colorScheme.dark=Tywyll
+aboutReader.colorScheme.sepia=Sepia
+aboutReader.colorScheme.auto=Awtomatig
+
+# LOCALIZATION NOTE (aboutReader.estimatedReadTimeValue1): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the number of minutes it is estimated to take to read the article
+# example: `3 minutes`
+aboutReader.estimatedReadTimeValue1=Dim munudau;#1 munud;#1 funud;#1 munud;#1 munud;#1 munud
+
+#LOCALIZATION NOTE (aboutReader.estimatedReadTimeRange1): Semi-colon list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# When there is some uncertainty in how long the article will take to read show a range of
+# minutes it is expected to take.
+# #1 is the number of minutes it is estimated to take to read the article for a fast reader
+# #2 is the number of minutes it is estimated to take to read the article for a slow reader
+# #2 is the variable used to determine the plural form to use.
+# example: `5-8 minutes`
+aboutReader.estimatedReadTimeRange1=Dim munudau;#1-#2 munud;#1-#2 munud;#1-#2 munud;#1-#2 munud;#1-#2 munud
+
+# LOCALIZATION NOTE (aboutReader.fontType.serif, aboutReader.fontType.sans-serif):
+# These are the styles of typeface that are options in the reader view controls.
+aboutReader.fontType.serif=Serif
+aboutReader.fontType.sans-serif=Sans-serif
+
+# LOCALIZATION NOTE (aboutReader.fontTypeSample): String used to sample font types.
+# For followup see: https://bugzilla.mozilla.org/show_bug.cgi?id=1637089 
+aboutReader.fontTypeSample=Aa
+
+aboutReader.toolbar.close=Cau'r Golwg Darllen
+aboutReader.toolbar.typeControls=Rheoli'r math
+
+# This is used as a label for the Reader View toolbar button.
+# This is a label used for the Save to Pocket option in the toolbar.
+# %S is replaced by Pocket.
+readerView.savetopocket.label=Cadw i %S
+# This is a label used for done option in the toolbar
+readerView.done.label=Gorffen
+# These are used for the Reader View toolbar button and the menuitem within the
+# View menu.
+readerView.enter=Mynd i'r Golwg Darllen
+readerView.enter.accesskey=D
+readerView.close=Cau'r Golwg Darllen
+readerView.close.accesskey=D
+
+# These are used as tooltips in Type Control
+aboutReader.toolbar.minus = Lleihau Maint Testun
+aboutReader.toolbar.plus = Cynyddu Maint Testun
+aboutReader.toolbar.contentwidthminus = Lleihau Lled Cynnwys
+aboutReader.toolbar.contentwidthplus = Cynyddu Lled Cynnwys
+aboutReader.toolbar.lineheightminus = Lleihau Uchder Llinell
+aboutReader.toolbar.lineheightplus = Cynyddu Uchder Llinell
+aboutReader.toolbar.colorschemelight = Cynllun Lliw Golau
+aboutReader.toolbar.colorschemedark = Cynllun Lliw Tywyll
+aboutReader.toolbar.colorschemesepia = Cynllun Lliw Sepia
diff --git a/l10n-cy/toolkit/chrome/global/aboutStudies.properties b/l10n-cy/toolkit/chrome/global/aboutStudies.properties
new file mode 100644
index 0000000000..657c144b3f
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/aboutStudies.properties
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# LOCALIZATION NOTE (title): keep "Shield" in English. See
+# https://wiki.mozilla.org/Firefox/Shield/Shield_Studies for more information
+title = Shield Studies
+removeButton = Tynnu
+
+# LOCALIZATION NOTE (activeStudiesList): Title above a list of active studies
+activeStudiesList = Astudiaethau byw
+# LOCALIZATION NOTE (activeStudiesList): Title above a list of completed studies
+completedStudiesList = Astudiaethau wedi'u cwblhau
+# LOCALIZATION NOTE (activeStatus): Displayed for an active study
+activeStatus = Gweithredol
+
+# LOCALIZATION NOTE (completeStatus): Displayed for a study that is already complete
+completeStatus = Cwblhawyd
+
+updateButtonWin = Ddiweddaru Dewisiadau
+updateButtonUnix = Diweddaru Dewisiadau
+learnMore = Dysgu rhagor
+noStudies = Nid ydych wedi cymryd rhan mewn unrhyw astudiaeth.
+disabledList = Dyma restr o astudiaethau rydych wedi cymryd rhan ynddynt. Ni fydd unrhyw astudiaethau newydd yn rhedeg.
+# LOCALIZATION NOTE (enabledList): %S is brandShortName (e.g. Firefox)
+enabledList = Beth yw hyn? Gall %S osod a rhedeg astudiaethau o bryd i'w gilydd.
+
+# LOCALIZATION NOTE (preferenceStudyDescription) $1%S will be replaced with the
+# name of a preference (such as "stream.improvesearch.topSiteSearchShortcuts")
+# and $2%S will be replaced with the value of that preference. Both values will
+# be formatted differently than the surrounding text.
+preferenceStudyDescription = Mae'r astudiaeth yn gosod %1$S i %2$S.
\ No newline at end of file
diff --git a/l10n-cy/toolkit/chrome/global/aboutWebrtc.properties b/l10n-cy/toolkit/chrome/global/aboutWebrtc.properties
new file mode 100644
index 0000000000..eddae0c219
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/aboutWebrtc.properties
@@ -0,0 +1,191 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (document_title):
+# The text "WebRTC" is a proper noun and should not be translated.
+# It is the general label for the standards based technology. see http://www.webrtc.org
+document_title = Materion Mewnol WebRTC
+cannot_retrieve_log = Methu estyn cofnod data WebRTC
+
+# LOCALIZATION NOTE (save_page_msg):
+# %1$S will be replaced by a full path file name: the target of the SavePage operation.
+save_page_msg = cadwyd y dudalen i: %1$S
+
+# LOCALIZATION NOTE (save_page_dialog_title): "about:webrtc" is a internal browser URL and should not be
+# translated. This string is used as a title for a file save dialog box.
+save_page_dialog_title = cadw about:webrtc fel
+
+# LOCALIZATION NOTE (debug_mode_off_state_msg):
+# %1$S will be replaced by the full path file name of the debug log.
+debug_mode_off_state_msg = mae modd canfod y cofnod olrhain yn: %1$S
+
+# LOCALIZATION NOTE (debug_mode_on_state_msg):
+# %1$S will be replaced by the full path file name of the debug log.
+debug_mode_on_state_msg = modd dadfygio'n weithredol, cofnod olrhain yn %1$S
+
+# LOCALIZATION NOTE (aec_logging_msg_label, aec_logging_off_state_label,
+# aec_logging_on_state_label, aec_logging_on_state_msg):
+# AEC is an abbreviation for Acoustic Echo Cancellation.
+aec_logging_msg_label = Cofnodi AEC
+aec_logging_off_state_label = Cychwyn Cofnodi AEC
+aec_logging_on_state_label = Atal Cofnodi AEC
+aec_logging_on_state_msg = Cofnodi AEC yn weithredol (siarad gyda'r galwr am ychydig funudau ac yna atal y cipio)
+
+# LOCALIZATION NOTE (aec_logging_off_state_msg):
+# %1$S will be replaced by the full path to the directory containing the captured log files.
+# AEC is an abbreviation for Acoustic Echo Cancellation.
+aec_logging_off_state_msg = mae'r ffeiliau cofnod y cipio yn: %1$S
+
+# LOCALIZATION NOTE (peer_connection_id_label): "PeerConnection" is a proper noun
+# associated with the WebRTC module. "ID" is an abbreviation for Identifier. This string
+# should not normally be translated and is used as a data label.
+peer_connection_id_label = Dynodiad PeerConnection
+
+# LOCALIZATION NOTE (sdp_heading, local_sdp_heading, remote_sdp_heading, sdp_history_heading, sdp_parsing_errors_heading):
+# "SDP" is an abbreviation for Session Description Protocol, an IETF standard.
+# See http://wikipedia.org/wiki/Session_Description_Protocol
+sdp_heading = SDP
+local_sdp_heading = SDP lleol
+remote_sdp_heading = SDP pell
+
+sdp_history_heading = Hanes SDP
+sdp_parsing_errors_heading = Gwallau Didoli SDP
+# LOCALIZATION NOTE (sdp_set_at_timestamp): the local or remote SDP and when it was set
+# %1$S will be replaced by local_sdp_heading or remote sdp_heading and %2$S
+# will be a numeric timestamp.
+sdp_set_at_timestamp = Gosod %1$S ar y stamp amser %2$S.
+# LOCALIZATION NOTE (sdp_set_timestamp): the absolute and relative times
+# when the sdp was set. %1$S and $2$S are both numeric timestamps. The
+# first is the absolute time, the second is the elapsed time since the
+# first sdp was set. ms is an abbreviation for milliseconds.
+sdp_set_timestamp = Stamp amser %1$S (+ %2$S ms)
+# LOCALIZATION NOTE (offer, answer):
+# offer and answer describe whether the local sdp is an offer or answer or
+# the remote sdp is an offer or answer.  These are appended to the local and
+# remote sdp headings.
+offer = Cynnig
+answer = Ateb
+
+# LOCALIZATION NOTE (rtp_stats_heading): "RTP" is an abbreviation for the
+# Real-time Transport Protocol, an IETF specification, and should not
+# normally be translated. "Stats" is an abbreviation for Statistics.
+rtp_stats_heading = Ystadegau RTP
+
+# LOCALIZATION NOTE (ice_state, ice_stats_heading): "ICE" is an abbreviation
+# for Interactive Connectivity Establishment, which is an IETF protocol,
+# and should not normally be translated. "Stats" is an abbreviation for
+# Statistics.
+ice_state = Cyflwr ICE
+ice_stats_heading = Ystadegau ICE
+ice_restart_count_label = Ailgychwyn ICE
+ice_rollback_count_label = Hen fersiynau ICE
+ice_pair_bytes_sent = Didau wedi'u hanfon
+ice_pair_bytes_received = Didau wedi'u derbyn
+ice_component_id = Enw'r Cydran
+
+# LOCALIZATION NOTE (avg_bitrate_label, avg_framerate_label): "Avg." is an abbreviation
+# for Average. These are used as data labels.
+avg_bitrate_label = Did radd cyfartalog
+avg_framerate_label = Ffrâm radd cyfartalog
+
+# LOCALIZATION NOTE (typeLocal, typeRemote): These adjectives are used to label a
+# line of statistics collected for a peer connection. The data represents
+# either the local or remote end of the connection.
+typeLocal = Lleol
+typeRemote = Pell
+
+# LOCALIZATION NOTE (nominated): This adjective is used to label a table column.
+# Cells in this column contain the localized javascript string representation of "true"
+# or are left blank.
+nominated = Enwebwyd
+
+# LOCALIZATION NOTE (selected): This adjective is used to label a table column.
+# Cells in this column contain the localized javascript string representation of "true"
+# or are left blank. This represents an attribute of an ICE candidate.
+selected = Dewiswyd
+
+# LOCALIZATION NOTE (trickle_caption_msg2, trickle_highlight_color_name2): ICE
+# candidates arriving after the remote answer arrives are considered trickled
+# (an attribute of an ICE candidate). These are highlighted in the ICE stats
+# table with light blue background. %S is replaced by
+# trickle_highlight_color_name2 ("blue"), highlighted with a light blue
+# background to visually match the trickled ICE candidates.
+trickle_caption_msg2 = Mae ymgeisydd diferu (yn cyrraedd ar ôl yr ateb) yn cael eu hamlygu mewn %S
+trickle_highlight_color_name2 = glas
+
+save_page_label = Cadw Tudalen
+debug_mode_msg_label = Modd Dadfygio
+debug_mode_off_state_label = Cychwyn y Modd Dadfygio
+debug_mode_on_state_label = Atal y Modd Dadfygio
+stats_heading = Ystadegau'r Sesiwn
+stats_clear = Clirio Hanes
+log_heading = Cofnod Cysylltu
+log_clear = Clirio'r Cofnod
+log_show_msg = dangos cofnod
+log_hide_msg = cuddio cofnod
+connection_closed = cau
+local_candidate = Ymgeisydd Lleol
+remote_candidate = Ymgeisydd Pell
+raw_candidates_heading = Pob Ymgeisydd Bras
+raw_local_candidate = Ymgeisydd Lleol Bras
+raw_remote_candidate = Ymgeisydd Pell Bras
+raw_cand_show_msg = dangos ymgeiswyr bras
+raw_cand_hide_msg = cuddio ymgeiswyr bras
+priority = Blaenoriaeth
+fold_show_msg = dangos manylion
+fold_show_hint = cliciwch i ehangu'r adran
+fold_hide_msg = cuddio manylion
+fold_hide_hint = cliciwch i gau'r adran
+dropped_frames_label = Fframiau hepgorwyd
+discarded_packets_label = Pacedi hepgorwyd
+decoder_label = Datgodwyr
+encoder_label = Amgodiwr
+received_label = Derbyniwyd
+packets = pacedi
+lost_label = Wedi'i golli
+jitter_label = Jitter
+sent_label = Anfonwyd
+
+show_tab_label = Dangos tab
+
+frame_stats_heading = Ystadegau Ffrâm Fideo
+n_a = Dim Ar Gael
+width_px = Lled (px)
+height_px = Uchder (px)
+consecutive_frames = Fframiau Olynol
+time_elapsed = Amser wedi Pasio
+estimated_framerate = Amcan o Raddfa Ffrâm
+rotation_degrees = Cylchdroi (graddau)
+first_frame_timestamp = Stamp Amser Derbyn y  Ffrâm Gyntaf
+last_frame_timestamp = Stamp Amser Derbyn y  Ffrâm Olaf
+# SSRCs are identifiers that represent endpoints in an RTP stream
+# This is an SSRC on the local side of the connection that is receiving RTP
+local_receive_ssrc = Derbyn SSRC  Lleol
+# This is an SSRC on the remote side of the connection that is sending RTP
+remote_send_ssrc = Anfon SSRC o Bell
+# An option whose value will not be displayed but instead noted as having been
+# provided
+configuration_element_provided = Wedi'i Ddarparu
+# An option whose value will not be displayed but instead noted as having not
+# been provided
+configuration_element_not_provided = Heb ei Ddarparu
+# The options set by the user in about:config that could impact a WebRTC call
+custom_webrtc_configuration_heading = Dewisiadau WebRTC Gosodedig y Defnyddiwr
+
+# Section header for estimated bandwidths of WebRTC media flows
+bandwidth_stats_heading = Amcangyfrif Lled Band
+# The ID of the MediaStreamTrack
+track_identifier = Dynodwr tracio
+# The estimated bandwidth available for sending WebRTC media in bytes per second
+send_bandwidth_bytes_sec = Lled Band Anfon (beit/eiliad)
+# The estimated bandwidth available for receiving WebRTC media in bytes per second
+receive_bandwidth_bytes_sec = Lled Band Derbyn (beit/eiliad)
+# Maximum number of bytes per second that will be padding zeros at the ends of packets
+max_padding_bytes_sec = Uchafswm Padio (beit/eiliad)
+# The amount of time inserted between packets to keep them spaced out
+pacer_delay_ms = Oedi Pacer ms
+# The amount of time it takes for a packet to travel from the local machine to the remote machine,
+# and then have a packet return
+round_trip_time_ms = RTT ms
+
diff --git a/l10n-cy/toolkit/chrome/global/appPicker.dtd b/l10n-cy/toolkit/chrome/global/appPicker.dtd
new file mode 100644
index 0000000000..f2ae20d749
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/appPicker.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY NoAppFound.label      "Heb ganfod rhaglen ar gyfer y math yma o ffeil.">
+<!ENTITY BrowseButton.label    "Pori…">
+<!ENTITY SendMsg.label         "Anfon yr eitem at:">
diff --git a/l10n-cy/toolkit/chrome/global/autocomplete.properties b/l10n-cy/toolkit/chrome/global/autocomplete.properties
new file mode 100644
index 0000000000..a311f5b31b
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/autocomplete.properties
@@ -0,0 +1,29 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (searchWithEngine, searchInPrivateWindowWithEngine): %S will
+# be replaced with the search engine provider's name. This format was chosen
+# because the provider can also end with "Search" (e.g.: MSN Search).
+searchWithEngine = Chwilio gyda %S
+
+searchInPrivateWindowWithEngine = Chwilio gyda %S mewn Ffenestr Breifat
+
+# LOCALIZATION NOTE (searchInPrivateWindow): Used when the private browsing
+# engine is the same as the default engine.
+searchInPrivateWindow = Chwilio mewn Ffenestr Breifat
+
+# LOCALIZATION NOTE (switchToTab2): This is the same as the older switchToTab
+# string that it's replacing, except it uses title case, so "Switch" and "Tab"
+# are capitalized.
+switchToTab2 = Newid i'r Tab
+
+# LOCALIZATION NOTE (visit): This is shown next to autocomplete entries that are
+# simple URLs or sites, which will be visited when the user selects them.
+visit = Ymweld â
+
+# LOCALIZATION NOTE (bookmarkKeywordSearch): This is the title of autocomplete
+# entries that are bookmark keyword searches.  %1$S will be replaced with the
+# domain name of the bookmark, and %2$S will be replaced with the keyword
+# search text that the user is typing.  %2$S will not be empty.
+bookmarkKeywordSearch = %1$S: %2$S
diff --git a/l10n-cy/toolkit/chrome/global/browser.properties b/l10n-cy/toolkit/chrome/global/browser.properties
new file mode 100644
index 0000000000..74cc051c90
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/browser.properties
@@ -0,0 +1,7 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+formPostSecureToInsecureWarning.title = Rhybudd Diogelwch
+formPostSecureToInsecureWarning.message = Mae'r wybodaeth rydych wedi ei gyflwyno ar fin cael ei yrru ar draws cysylltiad sydd heb ei hamgryptio a gall gael ei ddarllen gan drydydd parti.\n\nYdych chi'n siŵr eich bod eisiau parhau i yrru'r wybodaeth?
+formPostSecureToInsecureWarning.continue = Ymlaen
diff --git a/l10n-cy/toolkit/chrome/global/charsetMenu.dtd b/l10n-cy/toolkit/chrome/global/charsetMenu.dtd
new file mode 100644
index 0000000000..b917d036b3
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/charsetMenu.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY charsetMenu2.label            "Amgodiad Testun">
diff --git a/l10n-cy/toolkit/chrome/global/charsetMenu.properties b/l10n-cy/toolkit/chrome/global/charsetMenu.properties
new file mode 100644
index 0000000000..105a666568
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/charsetMenu.properties
@@ -0,0 +1,127 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: The property keys ending with ".key" are for access keys.
+# Localizations may add or delete properties where the property key ends with
+# ".key" as appropriate for the localization. The code that uses this data can
+# deal with the absence of an access key for an item.
+#
+# For gbk, gbk.bis and gbk.bis.key are used to trigger string changes in
+# localizations.
+#
+# In the en-US version of this file, access keys are given to the following:
+# * UTF-8
+# * All encodings that are the fallback encoding for some locale in Firefox
+# * All encodings that are the fallback encoding for some locale in IE
+# * All Japanese encodings
+#
+# For the items whose property key does not end in ".key" and whose value
+# includes "(" U+0028 LEFT PARENTHESIS, the "(" character is significant for
+# processing by CharsetMenu.jsm. If your localization does not use ASCII
+# parentheses where en-US does in this file, please file a bug to make
+# CharsetMenu.jsm also recognize the delimiter your localization uses.
+# (When this code was developed, all localizations appeared to use
+# U+0028 LEFT PARENTHESIS for this purpose.)
+
+# Auto-Detect (sub)menu
+charsetMenuCharsets = Nodau Amgodio
+charsetMenuAutodet = Awto-Ganfod
+# 'A' is reserved for Arabic:
+charsetMenuAutodet.key = D
+charsetMenuAutodet.off = (diffodd)
+charsetMenuAutodet.off.key = o
+charsetMenuAutodet.ru = Rwseg
+charsetMenuAutodet.ru.key = R
+charsetMenuAutodet.uk = Wcraneg
+charsetMenuAutodet.uk.key = U
+
+# Globally-relevant
+
+_autodetect_all.key =     m
+_autodetect_all     = Awtomatig
+UTF-8.key        = U
+UTF-8            = Unicode
+windows-1252.key = W
+windows-1252     = Gorllewinol
+
+# Arabic
+windows-1256.key = A
+windows-1256     = Arabaidd (Windows)
+ISO-8859-6       = Arabaidd (ISO)
+
+# Baltic
+windows-1257.key = B
+windows-1257     = Baltig (Windows)
+ISO-8859-4       = Baltig (ISO)
+
+# Central European
+windows-1250.key =         E
+windows-1250     = Canol Ewrop (Windows)
+ISO-8859-2.key   =       l
+ISO-8859-2       = Canol Ewrop (ISO)
+
+# Chinese, Simplified
+gbk.bis.key      =          S
+gbk.bis          = Tsieinëeg, Symledig
+
+# Chinese, Traditional
+Big5.key         =          T
+Big5             = Tsieinëeg Traddodiadol
+
+# Cyrillic
+windows-1251.key = C
+windows-1251     = Cyrilig (Windows)
+ISO-8859-5       = Cyrilig (ISO)
+KOI8-R           = Cyrilig (KOI8-R)
+KOI8-U           = Cyrilig (KOI8-U)
+IBM866           = Cyrilig (DOS)
+
+# UI string in anticipation of Cyrillic analog of bug 1543077;
+# deliberately not in use yet
+
+# LOCALIZATION NOTE (Cyrillic.key): If taken into use, this string will appear
+# instead of the string for windows-1251.key, so the use of the same
+# accelerator is deliberate.
+Cyrillic.key     = T
+# LOCALIZATION NOTE (Cyrillic): If taken into use, this string will appear
+# as a single item instead of the five items windows-1251, ISO-8859-5,
+# KOI8-R, KOI8-U, and IBM866, so this string does not need to make sense
+# together with those strings and should be translated the way those were
+# but omitting the part in parentheses.
+Cyrillic         = Cyrilig
+
+# Greek
+windows-1253.key = G
+windows-1253     = Groeg (Windows)
+ISO-8859-7.key   =          O
+ISO-8859-7       = Groeg (ISO)
+
+# Hebrew
+windows-1255.key = H
+windows-1255     = Hebraeg
+# LOCALIZATION NOTE (ISO-8859-8): The value for this item should begin with
+# the same word for Hebrew as the value for windows-1255 so that this item
+# sorts right after that one in the collation order for your locale.
+ISO-8859-8       = Hebraeg, Gweledol
+
+# Japanese (NOT AN ENCODING NAME)
+Japanese.key     = J
+Japanese         = Japanëeg
+
+# Korean
+EUC-KR.key       = o
+EUC-KR           = Corëeg
+
+# Thai
+windows-874.key  =    i
+windows-874      = Thai
+
+# Turkish
+windows-1254.key =   r
+windows-1254     = Twrceg
+
+# Vietnamese
+windows-1258.key = F
+windows-1258     = Fietnamaidd
+
diff --git a/l10n-cy/toolkit/chrome/global/commonDialog.dtd b/l10n-cy/toolkit/chrome/global/commonDialog.dtd
new file mode 100644
index 0000000000..9dfdb74282
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/commonDialog.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY editfield0.label "Enw Defnyddiwr:"> 
+<!ENTITY editfield1.label "Cyfrinair:"> 
+<!ENTITY copyCmd.label    "Copïo">
+<!ENTITY copyCmd.accesskey "C">
+<!ENTITY selectAllCmd.label "Dewis Popeth">
+<!ENTITY selectAllCmd.accesskey "P">
diff --git a/l10n-cy/toolkit/chrome/global/commonDialogs.properties b/l10n-cy/toolkit/chrome/global/commonDialogs.properties
new file mode 100644
index 0000000000..8a3efbb7ca
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/commonDialogs.properties
@@ -0,0 +1,34 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+Alert=Rhybudd
+Confirm=Cadarnhau
+ConfirmCheck=Cadarnhau
+Prompt=Anogiad
+# LOCALIZATION NOTE - %S is brandFullName
+PromptUsernameAndPassword3=Angen Dilysu - %S
+# LOCALIZATION NOTE - %S is brandFullName
+PromptPassword3=Angen Cyfrinair - %S
+Select=Dewis
+OK=Iawn
+Cancel=Diddymu
+Yes=&Iawn
+No=&Na
+Save=&Cadw
+Revert=&Dychwelyd
+DontSave=&Peidio â Chadw
+ScriptDlgGenericHeading=[Rhaglen JavaScript]
+ScriptDlgHeading=Mae tudalen %S yn dweud:
+ScriptDialogLabel=Atal y dudalen hon rhag creu deialogau ychwanegol
+ScriptDialogPreventTitle=Cadarnhau Dewisiadau Deialog
+# LOCALIZATION NOTE (EnterLoginForRealm3, EnterLoginForProxy3):
+# %1 is an untrusted string provided by a remote server. It could try to
+# take advantage of sentence structure in order to mislead the user (see
+# bug 244273). %1 should be integrated into the translated sentences as
+# little as possible. %2 is the url of the site being accessed.
+EnterLoginForRealm3=Mae %2$S yn gofyn am enw defnyddiwr a chyfrinair. Mae'r wefan yn dweud: “%1$S”
+EnterLoginForProxy3=Mae'r dirprwy %2$S yn gofyn am enw defnyddiwr a chyfrinair. Mae'r wefan yn dweud: “%1$S”
+EnterUserPasswordFor2=Mae %1$S yn gofyn am enw defnyddiwr a chyfrinair.
+EnterUserPasswordForCrossOrigin2=Mae %1$S yn gofyn am enw defnyddiwr a chyfrinair. RHYBUDD: Ni fydd eich cyfrinair yn cael ei anfon at y wefan rydych arni ar hyn o bryd!
+EnterPasswordFor=Rhowch gyfrinair ar gyfer %1$S ar %2$S
diff --git a/l10n-cy/toolkit/chrome/global/contentAreaCommands.properties b/l10n-cy/toolkit/chrome/global/contentAreaCommands.properties
new file mode 100644
index 0000000000..57347dc4b5
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/contentAreaCommands.properties
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# context menu strings
+
+SaveImageTitle=Cadw Delwedd
+SaveMediaTitle=Cadw'r Cyfryngau
+SaveVideoTitle=Cadw Fideo
+SaveAudioTitle=Cadw Sain
+SaveLinkTitle=Cadw Fel
+DefaultSaveFileName=mynegai
+WebPageCompleteFilter=Tudalen We, yn gyfan
+WebPageHTMLOnlyFilter=Tudalen We, HTML yn unig
+WebPageXHTMLOnlyFilter=Tudalen Gwe, XHTML yn unig
+WebPageSVGOnlyFilter=Tudalen gwe, SVG yn unig
+WebPageXMLOnlyFilter=Tudalen Gwe XML yn unig
+
+# LOCALIZATION NOTE (filesFolder):
+#    This is the name of the folder that is created parallel to a HTML file 
+#    when it is saved "With Images". The %S section is replaced with the
+#    leaf name of the file being saved (minus extension).
+filesFolder=%S_files
diff --git a/l10n-cy/toolkit/chrome/global/datetimebox.dtd b/l10n-cy/toolkit/chrome/global/datetimebox.dtd
new file mode 100644
index 0000000000..cc9d7f6ff3
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/datetimebox.dtd
@@ -0,0 +1,35 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Placeholders for input type=time -->
+
+<!ENTITY time.hour.placeholder "--">
+<!ENTITY time.minute.placeholder "--">
+<!ENTITY time.second.placeholder "--">
+<!ENTITY time.millisecond.placeholder "--">
+<!ENTITY time.dayperiod.placeholder "--">
+
+<!-- Field labels for input type=time -->
+
+<!ENTITY time.hour.label "Awr">
+<!ENTITY time.minute.label "Munud">
+<!ENTITY time.second.label "Eiliad">
+<!ENTITY time.millisecond.label "Milieiliad">
+<!ENTITY time.dayperiod.label "AM/PM">
+
+<!-- Placeholders for input type=date -->
+
+<!ENTITY date.year.placeholder "bbbb">
+<!ENTITY date.month.placeholder "mm">
+<!ENTITY date.day.placeholder "dd">
+
+<!-- Field labels for input type=date -->
+
+<!ENTITY date.year.label "Blwyddyn">
+<!ENTITY date.month.label "Mis">
+<!ENTITY date.day.label "Diwrnod">
+
+<!-- Date/time clear button -->
+
+<!ENTITY datetime.reset.label "Clirio">
diff --git a/l10n-cy/toolkit/chrome/global/dialog.properties b/l10n-cy/toolkit/chrome/global/dialog.properties
new file mode 100644
index 0000000000..86e5831f32
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/dialog.properties
@@ -0,0 +1,12 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+button-accept=Iawn
+button-cancel=Diddymu
+button-help=Cymorth
+button-disclosure=Rhagor o Wybodaeth
+accesskey-accept=
+accesskey-cancel=
+accesskey-help=C
+accesskey-disclosure=D
diff --git a/l10n-cy/toolkit/chrome/global/dialogOverlay.dtd b/l10n-cy/toolkit/chrome/global/dialogOverlay.dtd
new file mode 100644
index 0000000000..1b0def64e8
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/dialogOverlay.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- WARNING!!! This file is obsoleted by the dialog.xml widget -->
+<!-- OK Cancel Buttons -->
+
+
+<!ENTITY okButton.label      "Iawn">
+<!ENTITY cancelButton.label  "Diddymu">
diff --git a/l10n-cy/toolkit/chrome/global/editMenuOverlay.dtd b/l10n-cy/toolkit/chrome/global/editMenuOverlay.dtd
new file mode 100644
index 0000000000..b3fd3f63cc
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/editMenuOverlay.dtd
@@ -0,0 +1,11 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY findCmd.label             "Canfod">
+<!ENTITY findCmd.key               "F">
+<!ENTITY findCmd.accesskey         "f">
+<!ENTITY findAgainCmd.label        "Canfod Eto">
+<!ENTITY findAgainCmd.key          "G">
+<!ENTITY findAgainCmd.key2         "VK_F3">
+<!ENTITY findAgainCmd.accesskey    "a">
diff --git a/l10n-cy/toolkit/chrome/global/extensions.properties b/l10n-cy/toolkit/chrome/global/extensions.properties
new file mode 100644
index 0000000000..2cfa1518c4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/extensions.properties
@@ -0,0 +1,44 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+csp.error.missing-directive = Nid yw'r polisi'n cynnwys cyfarwyddeb '%S' angenrheidiol
+
+#LOCALIZATION NOTE (csp.error.illegal-keyword) %1$S is the name of a CSP directive, such as "script-src". %2$S is the name of a CSP keyword, usually 'unsafe-inline'.
+csp.error.illegal-keyword = Mae '%1$S' yn cynnwys cyfarwyddeb gwaharddedig allweddair %2$S
+
+#LOCALIZATION NOTE (csp.error.illegal-protocol) %2$S a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp.error.illegal-protocol = Mae '%1$S' yn cynnwys cyfarwyddeb gwaharddedig %2$S: protocol ffynhonnell
+
+#LOCALIZATION NOTE (csp.error.missing-host) %2$S a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp.error.missing-host = %2$S: mae'r protocol angen gwestai mewn cyfarwyddeb '%1$S'
+
+#LOCALIZATION NOTE (csp.error.missing-source) %1$S is the name of a CSP directive, such as "script-src". %2$S is the name of a CSP source, usually 'self'.
+csp.error.missing-source = Rhaid i '%1$S' gynnwys y ffynhonnell %2$S
+
+#LOCALIZATION NOTE (csp.error.illegal-host-wildcard) %2$S a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp.error.illegal-host-wildcard = %2$S: rhaid i ffynonellau cerdyn gwyllt o fewn cyfarwyddeb '%1$S' gynnwys o leiaf un isbarth generig (e.e., *.example.com yn lle *.com)
+
+#LOCALIZATION NOTE (uninstall.confirmation.title) %S is the name of the extension which is about to be uninstalled.
+uninstall.confirmation.title = Dadosod %S
+
+#LOCALIZATION NOTE (uninstall.confirmation.message) %S is the name of the extension which is about to be uninstalled.
+uninstall.confirmation.message = Mae estyniad “%S” yn gofyn am gael ei ddadosod. Beth hoffech chi ei wneud?
+
+uninstall.confirmation.button-0.label = Dadosod
+uninstall.confirmation.button-1.label = Cadw Wedi ei Osod
+
+saveaspdf.saveasdialog.title = Cadw Fel
+
+#LOCALIZATION NOTE (newTabControlled.message2) %S is the icon and name of the extension which updated the New Tab page.
+newTabControlled.message2 = Mae'r estyniad %S, wedi newid y ffenestr rydych yn ei weld pan fyddwch yn agor tab newydd.
+newTabControlled.learnMore = Dysgu rhagor
+
+#LOCALIZATION NOTE (homepageControlled.message) %S is the icon and name of the extension which updated the homepage.
+homepageControlled.message = Mae'r estyniad %S, wedi newid yr hyn rydych yn ei weld pan fyddwch yn agor eich tudalen cartref a ffenestri newydd.
+homepageControlled.learnMore = Dysgu rhagor
+
+#LOCALIZATION NOTE (tabHideControlled.message) %1$S is the icon and name of the extension which hid tabs, %2$S is the icon of the all tabs button.
+tabHideControlled.message = Mae estyniad, %1$S, yn cuddio rhai o'ch tabiau. Gallwch gael mynediad i'ch holl dabiau o %2$S.
+tabHideControlled.learnMore = Dysgu rhagor
+
diff --git a/l10n-cy/toolkit/chrome/global/fallbackMenubar.properties b/l10n-cy/toolkit/chrome/global/fallbackMenubar.properties
new file mode 100644
index 0000000000..83d9b7a9a3
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/fallbackMenubar.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# OSX only. Default menu label when there is no xul menubar.
+
+quitMenuitem.label=Gadael
+quitMenuitem.key=q
diff --git a/l10n-cy/toolkit/chrome/global/filepicker.properties b/l10n-cy/toolkit/chrome/global/filepicker.properties
new file mode 100644
index 0000000000..bd041ca71f
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/filepicker.properties
@@ -0,0 +1,18 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: The extensions to which these descriptions refer
+#                    now live in toolkit/content/filepicker.properties
+allTitle=Pob Ffeil
+htmlTitle=Ffeiliau HTML
+textTitle=Ffeiliau Testun
+imageTitle=Ffeiliau Delwedd
+xmlTitle=Ffeiliau XML
+xulTitle=Ffeiliau XUL
+appsTitle=Rhaglenni
+audioTitle=Ffeiliau Sain
+videoTitle=Ffeiliau Fideo
+
+formatLabel=Fformat:
+
diff --git a/l10n-cy/toolkit/chrome/global/findbar.properties b/l10n-cy/toolkit/chrome/global/findbar.properties
new file mode 100644
index 0000000000..3ec01b8b53
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/findbar.properties
@@ -0,0 +1,23 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# strings used by the Find bar, split from browser.properties
+NotFound=Heb ganfod ymadrodd
+WrappedToTop=Wedi cyrraedd diwedd y dudalen, parhau o'r brig
+WrappedToBottom=Wedi cyrraedd diwedd y dudalen, parhau o'r gwaelod
+NormalFind=Canfod ar y dudalen
+FastFind=Canfod cyflym
+FastFindLinks=Canfod cyflym (dolenni'n unig)
+CaseSensitive=(Mawr/bach)
+MatchDiacritics=(Diacritig cyfatebol)
+EntireWord=(Geiriau llawn yn unig)
+# LOCALIZATION NOTE (FoundMatches): Semicolon-separated list of plural forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is currently selected match and #2 the total amount of matches.
+FoundMatches=Dim cydweddiadau;#1 o #2 cydweddiad;#1 o #2 gydweddiad;#1 o #2 cydweddiad;#1 o #2 chydweddiad;#1 o #2 cydweddiad
+# LOCALIZATION NOTE (FoundMatchesCountLimit): Semicolon-separated list of plural
+# forms.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# #1 is the total amount of matches allowed before counting stops.
+FoundMatchesCountLimit=Dim cydweddiadau;Mwy nag #1 cydweddiad;Mwy na #1 gydweddiad;Mwy nag #1 chydweddiad;Mwy nag #1 chydweddiad;Mwy nag #1 cydweddiad
diff --git a/l10n-cy/toolkit/chrome/global/global-extension-fields.properties b/l10n-cy/toolkit/chrome/global/global-extension-fields.properties
new file mode 100644
index 0000000000..6eb474268d
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/global-extension-fields.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (extension.default-theme@mozilla.org.name, extension.default-theme@mozilla.org.description): This is displayed in about:addons -> Appearance
+extension.default-theme@mozilla.org.name=Rhagosodiad
+extension.default-theme@mozilla.org.description=Thema sydd â chynllun lliw'r system weithredu.
+
diff --git a/l10n-cy/toolkit/chrome/global/globalKeys.dtd b/l10n-cy/toolkit/chrome/global/globalKeys.dtd
new file mode 100644
index 0000000000..76b9235713
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/globalKeys.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY openHelp.commandkey     "VK_F1">
+<!ENTITY openHelpMac.commandkey  "?">
diff --git a/l10n-cy/toolkit/chrome/global/intl.css b/l10n-cy/toolkit/chrome/global/intl.css
new file mode 100644
index 0000000000..0221f963e1
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/intl.css
@@ -0,0 +1,7 @@
+/*
+ * This file contains all localizable skin settings such as 
+ *   font, layout, and geometry
+ */
+window { 
+  font: 3mm tahoma,arial,helvetica,sans-serif;
+}
diff --git a/l10n-cy/toolkit/chrome/global/intl.properties b/l10n-cy/toolkit/chrome/global/intl.properties
new file mode 100644
index 0000000000..e47e1a993e
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/intl.properties
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (intl.accept_languages):
+# This is a comma-separated list of valid BCP 47 language tags.
+#
+# Begin with the language tag of your locale. Next, include language
+# tags for other languages that you expect most users of your locale to be
+# able to speak, so that their browsing experience degrades gracefully if
+# content is not available in their primary language.
+#
+# It is recommended that you include "en-US, en" at the end of the list as a
+# last resort. However, if you know that users of your locale would prefer a
+# different variety of English, or if they are not likely to understand
+# English at all, you may opt to include a different English language tag, or
+# to exclude English altogether.
+#
+# For example, the Breton [br] locale might consider including French and
+# British English in their list, since those languages are commonly spoken in
+# the same area as Breton:
+# intl.accept_languages=br, fr-FR, fr, en-GB, en
+intl.accept_languages=cy-GB, cy, en-US, en
+
+# LOCALIZATION NOTE (font.language.group):
+# This preference controls the initial setting of the language drop-down menu
+# in the Content > Fonts & Colors > Advanced preference panel.
+#
+# Set it to the value of one of the menuitems in the "selectLangs" menulist in
+# http://dxr.mozilla.org/mozilla-central/source/browser/components/preferences/fonts.xul
+font.language.group=x-western
+
+# LOCALIZATION NOTE (intl.charset.detector):
+# This preference controls the initial setting for the character encoding
+# detector. Valid values are ja_parallel_state_machine for Japanese, ruprob
+# for Russian and ukprob for Ukrainian and the empty string to turn detection
+# off. The value must be empty for locales other than Japanese, Russian and
+# Ukrainian.
+intl.charset.detector=
+
+# LOCALIZATION NOTE (pluralRule): Pick the appropriate plural rule for your
+# language. This will determine how many plural forms of a word you will need
+# to provide and in what order.
+# See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+pluralRule=18
+
+# LOCALIZATION NOTE (intl.menuitems.alwaysappendaccesskeys, intl.menuitems.insertseparatorbeforeaccesskeys):
+# Valid values are: true, false, <empty string>
+# Missing preference or empty value equals false.
+intl.menuitems.alwaysappendaccesskeys=
+intl.menuitems.insertseparatorbeforeaccesskeys=true
diff --git a/l10n-cy/toolkit/chrome/global/keys.properties b/l10n-cy/toolkit/chrome/global/keys.properties
new file mode 100644
index 0000000000..0ca2e8c223
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/keys.properties
@@ -0,0 +1,78 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE : FILE This file contains the application's labels for keys on the keyboard.
+#                     If you decide to translate this file, you should translate it based on
+#                     the prevelant kind of keyboard for your target user.
+# LOCALIZATION NOTE : There are two types of keys, those w/ text on their labels
+#                     and those w/ glyphs.
+# LOCALIZATION NOTE : VK_<…> represents a key on the keyboard.
+#
+# For more information please see bugzilla bug 90888.
+
+# LOCALIZATION NOTE : FILE This file contains the application's labels for keys on the keyboard.
+#                     If you decide to translate this file, you should translate it based on
+#                     the prevalent kind of keyboard for your target user.
+# LOCALIZATION NOTE : There are two types of keys, those w/ text on their labels
+#                     and those w/ glyphs.
+# LOCALIZATION NOTE : VK_<…> represents a key on the keyboard.
+#
+# For more information please see bugzilla bug 90888.
+
+# F1..F10 should probably not be translated unless there are keyboards that actually have other labels
+# F11..F20 might be something else, but are really keyboard specific and not region/language specific
+# there are actually two different F11/F12 keys, I don't know which one these labels represent.
+# eg, F13..F20 on a sparc keyboard are labeled Props, Again .. Find, Cut
+# sparc also has Stop, Again and F11/F12. VK_F11/VK_F12 probably map to Stop/Again
+# LOCALIZATION NOTE : BLOCK Do not translate the next block
+VK_F1=F1
+VK_F2=F2
+VK_F3=F3
+VK_F4=F4
+VK_F5=F5
+VK_F6=F6
+VK_F7=F7
+VK_F8=F8
+VK_F9=F9
+VK_F10=F10
+
+VK_F11=F11
+VK_F12=F12
+VK_F13=F13
+VK_F14=F14
+VK_F15=F15
+VK_F16=F16
+VK_F17=F17
+VK_F18=F18
+VK_F19=F19
+VK_F20=F20
+# LOCALIZATION NOTE : BLOCK end do not translate block
+
+# LOCALIZATION NOTE : BLOCK GLYPHS, DO translate this block
+VK_UP=Saeth i Fyny
+VK_DOWN=Saeth i Lawr
+VK_LEFT=Saeth i'r Chwith
+VK_RIGHT=Saeth i'r Dde
+VK_PAGE_UP=Page Up
+VK_PAGE_DOWN=Page Down
+# LOCALIZATION NOTE : BLOCK end GLYPHS
+
+# Enter, backspace, and Tab might have both glyphs and text
+# if the keyboards usually have a glyph,
+# if there is a meaningful translation,
+# or if keyboards are localized
+# then translate them or insert the appropriate glyph
+# otherwise you should probably just translate the glyph regions
+
+VK_TAB=Tab
+VK_BACK=Backspace
+VK_DELETE=Del
+# LOCALIZATION NOTE : BLOCK end maybe GLYPHS
+# LOCALIZATION NOTE : BLOCK typing state keys
+VK_HOME=Home
+VK_END=End
+
+VK_ESCAPE=Esc
+VK_INSERT=Ins
+# LOCALIZATION NOTE : BLOCK end
diff --git a/l10n-cy/toolkit/chrome/global/mozilla.dtd b/l10n-cy/toolkit/chrome/global/mozilla.dtd
new file mode 100644
index 0000000000..8de8d39616
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/mozilla.dtd
@@ -0,0 +1,14 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY mozilla.title.11.14
+'Llyfr Mozilla, 11:14'>
+
+<!ENTITY mozilla.quote.11.14
+"Gwisgodd yr Anghenfil <em>ddillad newydd</em> ac astudio ffyrdd <em>Amser</em> a't <em>Gofod</em> 
+a't <em>Golau</em> a'r <em>Llif</em> egni drwy'r Bydysawd. O'i astudiaethau, lluniodd yr Anghenfil strwythurau newydd o <em>fetel wedi ei ocsideiddio</em> a datgan eu gogoniant.
+Llawenychodd dilynwyr yr Anghenfil, gan ganfod pwrpas newydd yn y <em>dysgeidiaethau</em> hyn.">
+
+<!ENTITY mozilla.from.11.14
+'o<strong>Lyfr Mozilla,</strong> 11:14'>
diff --git a/l10n-cy/toolkit/chrome/global/narrate.properties b/l10n-cy/toolkit/chrome/global/narrate.properties
new file mode 100644
index 0000000000..e63b29f667
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/narrate.properties
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# "Listen, which allows users to listen to Firefox reading the text, 
+# instead of having to read it themselves." This is the name
+# of the feature and it is the label for the popup button.
+listen = Gwrando
+back = Nôl
+start = Cychwyn
+stop = Atal
+forward = Ymlaen
+speed = Cyflymder
+selectvoicelabel = Llais:
+# Default voice is determined by the language of the document.
+defaultvoice = Rhagosodiad
+
+# Voice name and language.
+# eg. David (English)
+voiceLabel = %S (%S)
diff --git a/l10n-cy/toolkit/chrome/global/notification.dtd b/l10n-cy/toolkit/chrome/global/notification.dtd
new file mode 100644
index 0000000000..330d90cad4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/notification.dtd
@@ -0,0 +1,14 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY closeNotification.tooltip "Cau'r neges hon">
+
+<!ENTITY checkForUpdates "Gwirio am ddiweddariadau…">
+
+<!ENTITY learnMoreNoEllipsis "Dysgu rhagor">
+
+<!ENTITY defaultButton.label "Iawn!">
+<!ENTITY defaultButton.accesskey "I">
+
+<!ENTITY moreActionsButton.accessibleLabel "Rhagor o weithredoedd">
diff --git a/l10n-cy/toolkit/chrome/global/printdialog.properties b/l10n-cy/toolkit/chrome/global/printdialog.properties
new file mode 100644
index 0000000000..a0930388e5
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/printdialog.properties
@@ -0,0 +1,52 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# These strings are used in the native GTK, Mac and Windows print dialogs.
+
+# GTK titles:
+printTitleGTK=Argraffu
+optionsTabLabelGTK=Dewisiadau
+
+# Mac titles:
+optionsTitleMac=Dewisiadau:
+appearanceTitleMac=Golwg:
+pageHeadersTitleMac=Penawdau Tudalen:
+pageFootersTitleMac=Troedyn Tudalen:
+
+# Windows titles:
+optionsTitleWindows=Dewisiadau
+
+# TRANSLATOR NOTE: For radio button labels and check button labels, an underscore _
+# before a character will turn that character into an accesskey in the GTK dialog.
+# e.g. "_As laid out" will make A the accesskey.
+# In the Windows labels, use an ampersand (&).
+# On Mac, underscores will be stripped.
+
+shrinkToFit=Anwybyddu Graddio a _Lleihau i Ffitio Lled y Dudalen
+selectionOnly=Argraffu'r Dewis yn _Unig
+printBGOptions=Argraffu Cefndiroedd
+printBGColors=Argraffu _Lliwiau Cefndiroedd
+printBGImages=Argraffu _Delweddau Cefndir
+headerFooter=Pennyn a Throedyn
+left=Chwith
+center=Canol
+right=De
+headerFooterBlank=--gwag--
+headerFooterTitle=Teitl
+headerFooterURL=URL
+headerFooterDate=Dyddiad/Amser
+headerFooterPage=Tudalen #
+headerFooterPageTotal=Tudalen # o #
+headerFooterCustom=Cyfaddasu…
+customHeaderFooterPrompt=Rhowch destun eich pennyn/troedyn cyfaddas
+
+summarySelectionOnlyTitle=Dewis Argraffu
+summaryShrinkToFitTitle=Lleihau i'r Maint
+summaryPrintBGColorsTitle=Argraffu Lliwiau BG
+summaryPrintBGImagesTitle=Argraffu Delweddau BG
+summaryHeaderTitle=Pennyn Tudalen
+summaryFooterTitle=Troedyn Tudalen
+summaryNAValue=Dim
+summaryOnValue=Ymlaen
+summaryOffValue=Diffodd
diff --git a/l10n-cy/toolkit/chrome/global/resetProfile.dtd b/l10n-cy/toolkit/chrome/global/resetProfile.dtd
new file mode 100644
index 0000000000..426103ba1e
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/resetProfile.dtd
@@ -0,0 +1,7 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this file,
+   - You can obtain one at http://mozilla.org/MPL/2.0/.  -->
+
+<!ENTITY refreshProfile.dialog.title         "Adnewyddu &brandShortName;">
+
+<!ENTITY refreshProfile.cleaning.description "Bron â gorffen…">
diff --git a/l10n-cy/toolkit/chrome/global/resetProfile.properties b/l10n-cy/toolkit/chrome/global/resetProfile.properties
new file mode 100644
index 0000000000..98af519292
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/resetProfile.properties
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: These strings are used for profile reset.
+
+# LOCALIZATION NOTE (resetUnusedProfile.message): %S is brandShortName.
+resetUnusedProfile.message=Mae'n edrych fel nad ydych wedi cychwyn %S ers tro. Hoffech chi ei lanhau ar gyfer profiad fel newydd? A gyda llaw, croeso nôl!
+# LOCALIZATION NOTE (resetUninstalled.message): %S is brandShortName.
+resetUninstalled.message=Mae'n edrych fel eich bod wedi ailosod %S. Hoffech chi ei lanhau ar gyfer profiad fel newydd?
+
+# LOCALIZATION NOTE (refreshProfile.resetButton.label): %S is brandShortName.
+refreshProfile.resetButton.label=Adnewyddu %S…
+refreshProfile.resetButton.accesskey=A
diff --git a/l10n-cy/toolkit/chrome/global/textcontext.dtd b/l10n-cy/toolkit/chrome/global/textcontext.dtd
new file mode 100644
index 0000000000..29edb91650
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/textcontext.dtd
@@ -0,0 +1,24 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY spellAddToDictionary.label "Ychwanegu at y Geiriadur">
+<!ENTITY spellAddToDictionary.accesskey "Y">
+<!ENTITY spellUndoAddToDictionary.label "Dadwneud Ychwanegu at y Geiriadur">
+<!ENTITY spellUndoAddToDictionary.accesskey "D">
+<!ENTITY spellCheckToggle.label "Gwirio Sillafu">
+<!ENTITY spellCheckToggle.accesskey "G">
+<!ENTITY spellNoSuggestions.label "(Dim Awgrymiadau Sillafu)">
+<!ENTITY spellDictionaries.label "Ieithoedd">
+<!ENTITY spellDictionaries.accesskey "I">
+
+<!ENTITY searchTextBox.clear.label "Clirio">
+
+<!ENTITY fillLoginMenu.label          "Llanw'r Mewngofnodi">
+<!ENTITY fillLoginMenu.accesskey      "L">
+<!ENTITY fillPasswordMenu.label       "Llanw'r Cyfrinair">
+<!ENTITY fillPasswordMenu.accesskey   "L">
+<!ENTITY fillUsernameMenu.label       "Llanw'r Enw Defnyddiwr">
+<!ENTITY fillUsernameMenu.accesskey   "L">
+<!ENTITY noLoginSuggestions.label     "(Dim Awgrymiadau Mewngofnodi)">
+<!ENTITY viewSavedLogins.label        "Gweld y Mewngofnodi Lanwyd">
diff --git a/l10n-cy/toolkit/chrome/global/tree.dtd b/l10n-cy/toolkit/chrome/global/tree.dtd
new file mode 100644
index 0000000000..87e119aa63
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/tree.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY restoreColumnOrder.label "Adfer Trefn Colofnau">
diff --git a/l10n-cy/toolkit/chrome/global/videocontrols.dtd b/l10n-cy/toolkit/chrome/global/videocontrols.dtd
new file mode 100644
index 0000000000..d01e9a4793
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/videocontrols.dtd
@@ -0,0 +1,52 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY % brandDTD
+    SYSTEM "chrome://branding/locale/brand.dtd">
+  %brandDTD;
+
+<!ENTITY playButton.playLabel "Chwarae">
+<!ENTITY playButton.pauseLabel "Oedi">
+<!ENTITY muteButton.muteLabel "Tewi">
+<!ENTITY muteButton.unmuteLabel "Dad dewi">
+<!ENTITY fullscreenButton.enterfullscreenlabel "Sgrin Lawn">
+<!ENTITY fullscreenButton.exitfullscreenlabel "Gadael y Sgrin Lawn">
+<!ENTITY castingButton.castingLabel "Darlledu i'r Sgrin">
+<!ENTITY closedCaption.off "Diffodd">
+<!-- LOCALIZATION NOTE (volumeScrubber.label): This label is exposed to
+     accessibility software to clarify what the slider is for. -->
+<!ENTITY volumeScrubber.label "Llithrydd sain">
+
+<!-- LOCALIZATION NOTE (pictureInPicture.label): This string is used as part of
+the Picture-in-Picture video toggle button when the mouse is hovering it. -->
+<!ENTITY pictureInPicture.label "Llun mewn Llun">
+
+<!-- LOCALIZATION NOTE (pictureInPictureToggle.label): This string is used as the
+label for a variation of the Picture-in-Picture video toggle button when the mouse is
+hovering over the video. -->
+<!ENTITY pictureInPictureToggle.label "Gwylio yn Llun-mewn-Llun">
+<!-- LOCALIZATION NOTE (pictureInPictureExplainer): This string is used as part of
+a variation of the Picture-in-Picture video toggle button. When using this variation,
+this string appears below the toggle when the mouse hovers the toggle. -->
+<!ENTITY pictureInPictureExplainer "Gwylio fideos yn y blaendir tra'ch bod chi'n gwneud pethau eraill gyda &brandShortName;">
+
+<!ENTITY error.aborted "Mae llwytho'r fideo wedi dod i ben.">
+<!ENTITY error.network "Mae chwarae'r fideo wedi dod i ben oherwydd gwall rhwydwaith.">
+<!ENTITY error.decode "Nid oedd modd chwarae'r fideo gan fod y ffeil yn llwgr.">
+<!ENTITY error.srcNotSupported "Nid yw'r fformat fideo na'r math MIME yn cael eu cynnal.">
+<!ENTITY error.noSource2 "Heb ganfod fideo gyda fformat sy'n cael ei gynnal na math MIME.">
+<!ENTITY error.generic "Ataliwyd chwarae'r fideo oherwydd gwall anhysbys.">
+
+<!ENTITY status.pictureInPicture "Mae'r fideo hwn yn chwarae yn y modd Llun mewn Llun.">
+
+<!-- LOCALIZATION NOTE (positionAndDuration.nameFormat): the #1 string is the current
+media position, and the #2 string is the total duration. For example, when at
+the 5 minute mark in a 6 hour long video, #1 would be "5:00" and #2 would be
+"6:00:00", result string would be "5:00 / 6:00:00".
+Note that #2 is not always available. For example, when at the 5 minute mark in an
+unknown duration video, #1 would be "5:00" and the string which is surrounded by
+<span> would be deleted, result string would be "5:00".
+-->
+<!ENTITY positionAndDuration.nameFormat "#1<span> / #2</span>">
+
diff --git a/l10n-cy/toolkit/chrome/global/viewSource.properties b/l10n-cy/toolkit/chrome/global/viewSource.properties
new file mode 100644
index 0000000000..a29544bd7a
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/viewSource.properties
@@ -0,0 +1,16 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+goToLineTitle     = Mynd i'r llinell
+goToLineText      = Rhowch rif y llinell
+invalidInputTitle = Mewnbwn annilys
+invalidInputText  = Mae'r rhif roddwyd yn annilys.
+outOfRangeTitle   = Heb ganfod y llinell
+outOfRangeText    = Heb ganfod y linell hon.
+viewSelectionSourceTitle = Ffynhonnell DOM Dewis
+
+context_goToLine_label        = Mynd i Linell…
+context_goToLine_accesskey    = L
+context_wrapLongLines_label   = Amlapio Llinellau Hir
+context_highlightSyntax_label = Amlygu Cystrawen
diff --git a/l10n-cy/toolkit/chrome/global/wizard.properties b/l10n-cy/toolkit/chrome/global/wizard.properties
new file mode 100644
index 0000000000..a84087d2ac
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/wizard.properties
@@ -0,0 +1,8 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+default-first-title=Croeso i %S
+default-last-title=Cwblhau %S
+default-first-title-mac=Cyflwyniad
+default-last-title-mac=Diweddglo
diff --git a/l10n-cy/toolkit/chrome/mozapps/downloads/downloads.properties b/l10n-cy/toolkit/chrome/mozapps/downloads/downloads.properties
new file mode 100644
index 0000000000..3adc0bd28f
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/downloads.properties
@@ -0,0 +1,115 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (shortSeconds): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# s is the short form for seconds
+shortSeconds=e;e;e;e;e;e
+
+# LOCALIZATION NOTE (shortMinutes): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# m is the short form for minutes
+shortMinutes=m;m;m;m;m;m
+
+# LOCALIZATION NOTE (shortHours): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# h is the short form for hours
+shortHours=a;a;a;a;a;a
+
+# LOCALIZATION NOTE (shortDays): Semi-colon list of plural
+# forms. See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
+# d is the short form for days
+shortDays=d;d;d;d;d;d
+
+downloadErrorAlertTitle=Gwall llwytho i lawr
+# LOCALIZATION NOTE (downloadErrorBlockedBy): %S is the name of the blocking
+# extension.
+downloadErrorBlockedBy=Nid oes modd cadw'r llwyth am ei fod wedi'i rwystro gan %S.
+# LOCALIZATION NOTE (downloadErrorExtension): used when the blocking extension
+# name is unavailable.
+downloadErrorExtension=Nid oes modd cadw'r llwyth am ei fod wedi'i rwystro gan estyniad.
+downloadErrorGeneric=Nid oes modd cadw'r llwyth yma gan fod gwall anhysbys wedi digwydd.\n\nCeisiwch eto.
+
+# LOCALIZATION NOTE: we don't have proper plural support in the CPP code; bug 463102
+quitCancelDownloadsAlertTitle=Diddymu Pob Llwyth?
+quitCancelDownloadsAlertMsg=Os fyddwch yn gadael, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am adael?
+quitCancelDownloadsAlertMsgMultiple=Os fyddwch yn gadael, bydd %S llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael?
+quitCancelDownloadsAlertMsgMac=Os fyddwch yn gadael, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am adael?
+quitCancelDownloadsAlertMsgMacMultiple=Os fyddwch yn gadael, bydd %S llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael?
+offlineCancelDownloadsAlertTitle=Diddymu Pob Llwyth?
+offlineCancelDownloadsAlertMsg=Os fyddwch yn mynd all-lein, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am fynd all-lein?
+offlineCancelDownloadsAlertMsgMultiple=Os fyddwch yn mynd all-lein, bydd %S llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am fynd all-lein?
+leavePrivateBrowsingCancelDownloadsAlertTitle=Diddymu Pob Llwyth?
+leavePrivateBrowsingWindowsCancelDownloadsAlertMsg2=Os ydych yn cau pob ffenestr Pori Preifat nawr, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am adael y modd Pori Preifat?
+leavePrivateBrowsingWindowsCancelDownloadsAlertMsgMultiple2=Os ydych yn cau pob ffenestr Pori Preifat nawr, bydd %S llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael y modd Pori Preifat?
+cancelDownloadsOKText=Diddymu 1 Llwyth
+cancelDownloadsOKTextMultiple=Diddymu %S Llwyth
+dontQuitButtonWin=Peidio Gadael
+dontQuitButtonMac=Peidio Gorffen
+dontGoOfflineButton=Aros Ar-lein
+dontLeavePrivateBrowsingButton2=Aros yn y Modd Pori Preifat
+
+# LOCALIZATION NOTE (infiniteRate):
+# If download speed is a JavaScript Infinity value, this phrase is used
+infiniteRate=Cyflym iawn
+
+# LOCALIZATION NOTE (statusFormat3): — is the "em dash" (long dash)
+# %1$S transfer progress; %2$S rate number; %3$S rate unit; %4$S time left
+# example: 4 minutes left — 1.1 of 11.1 GB (2.2 MB/sec)
+statusFormat3=%4$S — %1$S (%2$S %3$S/sec)
+
+# LOCALIZATION NOTE (statusFormatInfiniteRate): — is the "em dash" (long dash)
+# %1$S transfer progress; %2$S substitute phrase for Infinity speed; %3$S time left
+# example: 4 minutes left — 1.1 of 11.1 GB (Really fast)
+statusFormatInfiniteRate=%3$S — %1$S (%2$S)
+
+# LOCALIZATION NOTE (statusFormatNoRate): — is the "em dash" (long dash)
+# %1$S transfer progress; %2$S time left
+# example: 4 minutes left — 1.1 of 11.1 GB
+statusFormatNoRate=%2$S — %1$S
+
+bytes=beit
+kilobyte=KB
+megabyte=MB
+gigabyte=GB
+
+# LOCALIZATION NOTE (transferSameUnits2):
+# %1$S progress number; %2$S total number; %3$S total unit
+# example: 1.1 of 333 MB
+transferSameUnits2=%1$S o %2$S %3$S
+# LOCALIZATION NOTE (transferDiffUnits2):
+# %1$S progress number; %2$S progress unit; %3$S total number; %4$S total unit
+# example: 11.1 MB of 3.3 GB
+transferDiffUnits2=%1$S %2$S o %3$S %4$S
+# LOCALIZATION NOTE (transferNoTotal2):
+# %1$S progress number; %2$S unit
+# example: 111 KB
+transferNoTotal2=%1$S %2$S
+
+# LOCALIZATION NOTE (timePair3): %1$S time number; %2$S time unit
+# example: 1m; 11h
+timePair3=%1$S %2$S
+# LOCALIZATION NOTE (timeLeftSingle3): %1$S time left
+# example: 1m left; 11h left
+timeLeftSingle3=%1$S ar ôl
+# LOCALIZATION NOTE (timeLeftDouble3): %1$S time left; %2$S time left sub units
+# example: 11h 2m left; 1d 22h left
+timeLeftDouble3=%1$S %2$S ar ôl
+timeFewSeconds2=Ychydig eiliadau ar ôl
+timeUnknown2=Amser anhysbys ar ôl
+
+# LOCALIZATION NOTE (doneScheme2): #1 URI scheme like data: jar: about:
+doneScheme2=Adnodd %1$S
+# LOCALIZATION NOTE (doneFileScheme): Special case of doneScheme for file:
+# This is used as an eTLD replacement for local files, so make it lower case
+doneFileScheme=ffeil leol
+
+# LOCALIZATION NOTE (yesterday): Displayed time for files finished yesterday
+yesterday=Ddoe
+
+fileExecutableSecurityWarning=Mae "%S" yn ffeil weithredadwy. Gall ffeiliau gweithredadwy gynnwys firysau neu god maleisus arall gall ddifrodi eich cyfrifiadur. Byddwch ofalus wrth agor y ffeil. Ydych chi'n siŵr eich bod am agor "%S"?
+fileExecutableSecurityWarningTitle=Agor Ffeil Gweithredadwy?
+
+# Desktop folder name for downloaded files
+downloadsFolder=Llwythi
diff --git a/l10n-cy/toolkit/chrome/mozapps/downloads/settingsChange.dtd b/l10n-cy/toolkit/chrome/mozapps/downloads/settingsChange.dtd
new file mode 100644
index 0000000000..ecaa4961ae
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/settingsChange.dtd
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  settingsChangePreferences.label  "Mae modd newid gosodiadau yn Dewisiadau &brandShortName;.">
+<!ENTITY  settingsChangeOptions.label      "Mae modd newid gosodiadau yn Newisiadau &brandShortName;.">
diff --git a/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.dtd b/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.dtd
new file mode 100644
index 0000000000..9e18d3a09f
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.dtd
@@ -0,0 +1,26 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY  intro2.label                "Rydych wedi dewis agor:">
+<!ENTITY  from.label                  "oddi wrth:">
+<!ENTITY  actionQuestion.label        "Beth ddylai &brandShortName; wneud gyda'r ffeil?">
+
+<!ENTITY  openWith.label              "Agor gyda">
+<!ENTITY  openWith.accesskey          "o">
+<!ENTITY  other.label                 "Arall…">
+
+<!ENTITY  saveFile.label              "Cadw Ffeil">
+<!ENTITY  saveFile.accesskey          "C">
+
+<!ENTITY  rememberChoice.label        "Gwneud hyn yn awtomatig ar gyfer ffeiliau o'r math yma o hyn ymlaen.">
+<!ENTITY  rememberChoice.accesskey    "a">
+
+<!ENTITY  whichIs.label              "sydd yn:">
+
+<!ENTITY  chooseHandlerMac.label      "Dewis…">
+<!ENTITY  chooseHandlerMac.accesskey  "D">
+<!ENTITY  chooseHandler.label         "Pori…">
+<!ENTITY  chooseHandler.accesskey     "P">
+
+<!ENTITY  unknownPromptText.label     "Hoffech chi gadw'r ffeil?">
diff --git a/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.properties b/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.properties
new file mode 100644
index 0000000000..5ecedcca6d
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.properties
@@ -0,0 +1,24 @@
+# -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+title=Yn agor %S
+saveDialogTitle=Rhowch enw'r ffeil i'w cadw iddi…
+defaultApp=%S (rhagosodiad)
+chooseAppFilePickerTitle=Dewis Rhaglen Cymorth
+badApp=Methu canfod y rhaglen ("%S") rydych wedi ei dewis.  Gwiriwch enw'r ffeil neu ddewis raglen arall.
+badApp.title=Methu canfod y rhaglen
+badPermissions=Nid oedd modd cadw'r ffeil am nad oedd gennych ganiatad i wneud hynny.  Dewiswch gyfeiriadur cadw arall.
+badPermissions.title=Caniatâd Cadw Annilys
+unknownAccept.label=Cadw Ffeil
+unknownCancel.label=Diddymu
+fileType=Ffeil %S
+# LOCALIZATION NOTE (orderedFileSizeWithType): first %S is type, second %S is size, and third %S is unit
+orderedFileSizeWithType=%1$S (%2$S %3$S)
+pdfHandlerDescription=Fformat Dogfen Gludadwy
+avifExtHandlerDescription=Ffeil Delwedd AV1 (AVIF)
+pdfExtHandlerDescription=Portable Document Format (PDF)
+svgExtHandlerDescription=Scalable Vector Graphics (SVG)
+webpExtHandlerDescription=Delwedd WebP
+xmlExtHandlerDescription=Extensible Markup Language (XML)
diff --git a/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.dtd b/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.dtd
new file mode 100644
index 0000000000..42c0ab2297
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.dtd
@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY setting.learnmore "Dysgu Rhagor…">
diff --git a/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.properties b/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.properties
new file mode 100644
index 0000000000..3d034f5bfd
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/extensions/extensions.properties
@@ -0,0 +1,84 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#LOCALIZATION NOTE (notification.incompatible) %1$S is the add-on name, %2$S is brand name, %3$S is application version
+notification.incompatible=Mae %1$S yn anghydnaws â %2$S %3$S.
+#LOCALIZATION NOTE (notification.unsigned, notification.unsignedAndDisabled) %1$S is the add-on name, %2$S is brand name
+notification.unsignedAndDisabled=Nid oedd modd dilysu %1$S i'w ddefnyddio yn %2$S ac mae wedi ei analluogi.
+notification.unsigned=Nid oedd modd dilysu %1$S i'w defnyddio yn %2$S. Cymerwch ofal.
+notification.unsigned.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (notification.blocked) %1$S is the add-on name
+notification.blocked=Mae %1$S wedi ei analluogi o ganlyniad i faterion diogelwch a sefydlogrwydd.
+notification.blocked.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (notification.softblocked) %1$S is the add-on name
+notification.softblocked=Mae'n hysbys fod %1$S yn achosi anawsterau diogelwch a sefydlogrwydd.
+notification.softblocked.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (notification.outdated) %1$S is the add-on name
+notification.outdated=Mae diweddariad pwysig ar gael ar gyfer %1$S.
+notification.outdated.link=Diweddaru Nawr
+#LOCALIZATION NOTE (notification.vulnerableUpdatable) %1$S is the add-on name
+notification.vulnerableUpdatable=Mae'n hysbys fod %1$S yn fregus a dylai gael ei ddiweddaru.
+notification.vulnerableUpdatable.link=Diweddaru Nawr
+#LOCALIZATION NOTE (notification.vulnerableNoUpdate) %1$S is the add-on name
+notification.vulnerableNoUpdate=Mae'n hysbys fod %1$S yn fregus. Defnyddiwch gyda gofal.
+notification.vulnerableNoUpdate.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (notification.restartless-uninstall) %1$S is the add-on name
+notification.restartless-uninstall=Bydd %1$S yn cael ei ddadosod ar ôl i chi gau'r tab.
+#LOCALIZATION NOTE (notification.downloadError) %1$S is the add-on name.
+notification.downloadError=Bu gwall wrth lwytho %1$S i lawr.
+notification.downloadError.retry=Ceisio eto
+notification.downloadError.retry.tooltip=Ceisiwch lwytho'r ychwanegyn eto
+#LOCALIZATION NOTE (notification.installError) %1$S is the add-on name.
+notification.installError=Bu gwall wrth osod %1$S.
+notification.installError.retry=Ceisio eto
+notification.installError.retry.tooltip=Ceisiwch lwytho i lawr a gosod yr ychwanegyn yma eto
+#LOCALIZATION NOTE (notification.gmpPending) %1$S is the add-on name.
+notification.gmpPending=Bydd %1$S yn cael ei osod yn fuan.
+
+#LOCALIZATION NOTE (details.notification.incompatible) %1$S is the add-on name, %2$S is brand name, %3$S is application version
+details.notification.incompatible=Mae %1$S yn anghydnaws â %2$S %3$S.
+#LOCALIZATION NOTE (details.notification.unsigned, details.notification.unsignedAndDisabled) %1$S is the add-on name, %2$S is brand name
+details.notification.unsignedAndDisabled=Nid oedd modd dilysu %1$S i'w ddefnyddio yn %2$S ac mae wedi ei analluogi.
+details.notification.unsigned=Nid oedd modd dilysu %1$S i'w defnyddio yn %2$S. Cymerwch ofal.
+details.notification.unsigned.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (details.notification.blocked) %1$S is the add-on name
+details.notification.blocked=Mae %1$S wedi ei analluogi o ganlyniad i faterion diogelwch a sefydlogrwydd.
+details.notification.blocked.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (details.notification.softblocked) %1$S is the add-on name
+details.notification.softblocked=Mae'n hysbys fod %1$S yn achosi anawsterau diogelwch a sefydlogrwydd.
+details.notification.softblocked.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (details.notification.outdated) %1$S is the add-on name
+details.notification.outdated=Mae diweddariad pwysig ar gael ar gyfer %1$S.
+details.notification.outdated.link=Diweddaru Nawr
+#LOCALIZATION NOTE (details.notification.vulnerableUpdatable) %1$S is the add-on name
+details.notification.vulnerableUpdatable=Mae'n hysbys fod %1$S yn fregus a dylai gael ei ddiweddaru.
+details.notification.vulnerableUpdatable.link=Diweddaru Nawr
+#LOCALIZATION NOTE (details.notification.vulnerableNoUpdate) %1$S is the add-on name
+details.notification.vulnerableNoUpdate=Mae'n hysbys fod %1$S yn fregus. Defnyddiwch gyda gofal.
+details.notification.vulnerableNoUpdate.link=Rhagor o Wybodaeth
+#LOCALIZATION NOTE (details.notification.restartless-uninstall) %1$S is the add-on name.
+details.notification.restartless-uninstall=Bydd %1$S yn cael ei ddadosod ar ôl i chi gau'r tab.
+#LOCALIZATION NOTE (details.notification.gmpPending) %1$S is the add-on name
+details.notification.gmpPending=Bydd %1$S yn cael ei osod yn fuan.
+
+type.extension.name=Estyniadau
+type.themes.name=Themâu
+type.locale.name=Iaith
+type.plugin.name=Ategion
+type.dictionary.name=Geiriaduron
+type.service.name=Gwasanaethau
+type.legacy.name=Hen Estyniadau
+type.unsupported.name=Heb eu Cynnal
+
+#LOCALIZATION NOTE(listHeading.discover) %S is the brandShortName
+listHeading.discover=Personoli Eich %S
+listHeading.extension=Rheoli eich estyniadau
+listHeading.shortcuts=Rheoli Estyniad Llwybrau Byr
+listHeading.theme=Rheoli eich themâu
+listHeading.plugin=Rheoli eich ategion
+listHeading.locale=Rheoli eich ieithoedd
+listHeading.dictionary=Rheoli eich geiriaduron
+
+searchLabel.extension=Canfod estyniadau eraill
+searchLabel.theme=Canfod themâu eraill
diff --git a/l10n-cy/toolkit/chrome/mozapps/handling/handling.dtd b/l10n-cy/toolkit/chrome/mozapps/handling/handling.dtd
new file mode 100644
index 0000000000..b250ba8c3c
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/handling/handling.dtd
@@ -0,0 +1,10 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!ENTITY window.emWidth "26em">
+<!ENTITY window.emHeight "26em">
+<!ENTITY ChooseOtherApp.description "Dewis Rhaglen arall">
+<!ENTITY ChooseApp.label "Dewis…">
+<!ENTITY ChooseApp.accessKey "D">
+<!ENTITY accept "Agor dolen">
diff --git a/l10n-cy/toolkit/chrome/mozapps/handling/handling.properties b/l10n-cy/toolkit/chrome/mozapps/handling/handling.properties
new file mode 100644
index 0000000000..b215fc17a2
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/handling/handling.properties
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+protocol.title=Cychwyn y Rhaglen
+protocol.description=Mae angen agor y ddolen gyda rhaglen.
+protocol.choices.label=Anfon at:
+protocol.checkbox.label=Cofio fy newis ar gyfer dolenni %S.
+protocol.checkbox.accesskey=C
+protocol.checkbox.extra=Gall hyn gael ei newid yn Newisiadau %S.
+
+# Displayed under the name of a protocol handler in the Launch Application dialog.
+privatebrowsing.disabled.label=Analluogwyd mewn Ffenestri Preifat
+
+choose.application.title=Rhaglen Arall…
diff --git a/l10n-cy/toolkit/chrome/mozapps/profile/profileSelection.properties b/l10n-cy/toolkit/chrome/mozapps/profile/profileSelection.properties
new file mode 100644
index 0000000000..5f8e18446b
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/profile/profileSelection.properties
@@ -0,0 +1,57 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: These strings are used for startup/profile problems and the profile manager.
+
+# Application not responding
+# LOCALIZATION NOTE (restartTitle, restartMessageNoUnlocker2, restartMessageUnlocker, restartMessageNoUnlockerMac, restartMessageUnlockerMac): Messages displayed when the application is running but is not responding to commands. %S is the application name.
+restartTitle=Cau %S
+restartMessageNoUnlocker2=Mae %S eisoes yn rhedeg, ond nid yw'n ymateb. I ddefnyddio %S, yn gyntaf rhaid i chi gau'r broses %S bresennol, ailgychwynnwch eich dyfais, neu ddefnyddio proffil gwahanol.
+restartMessageUnlocker=Mae %S yn rhedeg ond nid yw'n ymateb. Rhaid cau'r hen broses %S cyn agor ffenestr newydd.
+restartMessageNoUnlockerMac=Mae copi o %S eisoes ar agor. Dim ond un copi o %S gall fod ar agor ar unrhyw adeg.
+restartMessageUnlockerMac=Mae copi o %S eisoes ar agor. Bydd y copi o %S sy'n rhedeg yn cau er mwyn agor hon.
+
+# Profile manager
+# LOCALIZATION NOTE (profileTooltip): First %S is the profile name, second %S is the path to the profile folder.
+profileTooltip=Proffil: '%S' - Llwybr: '%S'
+
+pleaseSelectTitle=Dewis Proffil
+pleaseSelect=Dewiswch broffil i gychwyn %S, neu greu proffil newydd.
+
+renameProfileTitle=Newid Enw Proffil
+renameProfilePrompt=Ailenwi'r proffil "%S" i:
+
+profileNameInvalidTitle=Enw proffil annilys
+profileNameInvalid=Methu caniatáu enw proffil "%S".
+
+chooseFolder=Dewiswch Ffolder Proffil
+profileNameEmpty=Methu derbyn enw proffil gwag.
+invalidChar=Methu cynnwys nod "%S" mewn enw proffil. Dewiswch enw arall.
+
+deleteTitle=Dileu Proffil
+deleteProfileConfirm=Bydd dileu proffil yn tynnu'r proffil o'r rhestr o broffiliau sydd ar gael ac nid oes modd ei ddadwneud.\nGallwch hefyd ddewis i ddileu ffeiliau data proffil, gan gynnwys eich gosodiadau, tystysgrifau a data arall yn perthyn i ddefnyddwyr. Bydd y dewis hwn yn dileu ffolder "%S" ac nid oes modd ei ddadwneud.\nHoffech chi ddileu'r ffeiliau data proffil?
+deleteFiles=Dileu Ffeiliau
+dontDeleteFiles=Peidio Dileu Ffeiliau
+
+profileCreationFailed=Methu creu proffil. Mwy na thebyg mae'r ffolder yn anysgrifenadwy.
+profileCreationFailedTitle=Methodd creu Proffil
+profileExists=Mae proffil gyda'r enw eisoes yn bod. Dewiswch enw arall.
+profileFinishText=Cliciwch Gorffen i greu'r proffil newydd.
+profileFinishTextMac=Cliciwch Gorffen i greu'r proffil newydd.
+profileMissing=Methu llwytho eich proffil %S. Gall fod ar goll neu anhygyrch.
+profileMissingTitle=Proffil ar Goll
+profileDeletionFailed=Nid oedd modd dileu'r proffil gan efallai ei fod yn cael ei ddefnyddio.
+profileDeletionFailedTitle=Methodd y Dileu
+
+# Profile reset
+# LOCALIZATION NOTE (resetBackupDirectory): Directory name for the profile directory backup created during reset. This directory is placed in a location users will see it (ie. their desktop). %S is the application name.
+resetBackupDirectory=Hen Ddata %S
+
+flushFailTitle=Heb gadw'r newidiadau
+# LOCALIZATION NOTE (conflictMessage): %1$S is brandProductName, %2$S is brandShortName.
+conflictMessage=Mae copi arall o %1$S wedi gwneud newidiadau i broffiliau. Rhaid ailgychwyn %2$S cyn gwneud mwy o newidiadau.
+flushFailMessage=Mae gwall annisgwyl wedi atal eich newidiadau rhag cael eu cadw.
+# LOCALIZATION NOTE (flushFailRestartButton): $S is brandShortName.
+flushFailRestartButton=Ailgychwyn %S
+flushFailExitButton=Gadael
diff --git a/l10n-cy/toolkit/chrome/mozapps/update/updates.properties b/l10n-cy/toolkit/chrome/mozapps/update/updates.properties
new file mode 100644
index 0000000000..4e5d49997b
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/update/updates.properties
@@ -0,0 +1,45 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE: The 1st %S is brandShortName and 2nd %S is update version
+# where update version from the update xml
+# example: MyApplication 10.0.5
+updateName=%S %S
+
+noThanksButton=Dim Diolch
+noThanksButton.accesskey=i
+# NOTE: The restartLaterButton string is also used in
+# mozapps/extensions/content/blocklist.js
+restartLaterButton=Ailgychwyn Rhywbryd Eto
+restartLaterButton.accesskey=l
+restartNowButton=Ailgychwyn %S
+restartNowButton.accesskey=i
+
+statusFailed=Methodd y Gosod
+
+installSuccess=Cafodd y Diweddariad ei osod yn llwyddiannus
+installPending=Gosod yn Disgwyl
+patchApplyFailure=Methu gosod y Diweddariad (methodd gosod y darn)
+elevationFailure=Nid oes gennych y caniatâd angenrheidiol i osod y diweddariad. Cysylltwch â' ch gweinyddwr system.
+
+check_error-200=Ffeil XML diweddaru wedi ei gam-ffurfio (200)
+check_error-403=Gwrthod mynediad (403)
+check_error-404=Heb ganfod Ffeil Diweddaru XML (404)
+check_error-500=Gwall gweinydd mewnol (500)
+check_error-2152398849=Methwyd (rheswm anhysbys)
+check_error-2152398861=Gwrthodwyd cysylltiad
+check_error-2152398862=Cysylltiad wedi dod i ben
+# NS_ERROR_OFFLINE
+check_error-2152398864=Rhwydwaith all-lein (ewch ar-lein)
+check_error-2152398867=Gwrthod pyrth
+check_error-2152398868=Heb dderbyn data (ceisiwch eto)
+check_error-2152398878=Heb ganfod diweddariad gweinydd (gwirio'r cyswllt i'r we)
+check_error-2152398890=Heb ganfod gweinydd dirprwy (gwirio'r cyswllt i'r we)
+# NS_ERROR_DOCUMENT_NOT_CACHED
+check_error-2152398918=Rhwydwaith all-lein (ewch ar-lein)
+check_error-2152398919=Torrwyd ar drosglwyddiad data (ceisiwch eto)
+check_error-2152398920=Gwrthodwyd cysylltiad â'r gweinydd dirprwy
+check_error-2153390069=Mae tystysgrif y gweinydd wedi dod i ben (newidiwch gloc eich system i'r dyddiad a'r amser cywir os yw'n anghywir)
+check_error-verification_failed=Nid oedd modd dilysu cywirdeb y diweddariad
+check_error-move_failed=Wedi methu paratoi'r diweddariad i'w osod
diff --git a/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties b/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties
new file mode 100644
index 0000000000..f5572bf254
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties
@@ -0,0 +1,74 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+rememberPassword = Defnyddio'r Rheolwr Cyfrinair i gofio'r cyfrinair.
+savePasswordTitle = Cadarnhau
+# LOCALIZATION NOTE (saveLoginMsg, saveLoginMsgNoUser):
+# %1$S is brandShortName, %2$S is the login's hostname.
+saveLoginMsg = Hoffech chi i %1$S gadw'r mewngofnodiad hwn ar gyfer %2$S?
+saveLoginMsgNoUser = Hoffech chi i %1$S gadw'r cyfrinair hwn ar gyfer %2$S?
+saveLoginButtonAllow.label = Cadw
+saveLoginButtonAllow.accesskey = C
+saveLoginButtonDeny.label = Peidio â Chadw
+saveLoginButtonDeny.accesskey = P
+saveLoginButtonNever.label = Peidio Byth â Chadw
+saveLoginButtonNever.accesskey = P
+updateLoginMsg = Hoffech chi ddiweddaru'r mewngofnod?
+updateLoginMsgNoUser = Hoffech chi ddiweddaru'r cyfrinair?
+updateLoginMsgAddUsername = Hoffech chi ychwanegu enw defnyddiwr at y cyfrinair a gadwyd?
+updateLoginButtonText = Diweddaru
+updateLoginButtonAccessKey = i
+updateLoginButtonDeny.label = Peidio â Diweddaru
+updateLoginButtonDeny.accesskey = P
+updateLoginButtonDelete.label = Tynnu Mewngofnod wedi'i Gadw
+updateLoginButtonDelete.accesskey = T
+# LOCALIZATION NOTE (rememberPasswordMsg):
+# 1st string is the username for the login, 2nd is the login's hostname.
+# Note that long usernames may be truncated.
+rememberPasswordMsg = Hoffech chi gofio cyfrinair ar gyfer "%1$S" ar %2$S?
+# LOCALIZATION NOTE (rememberPasswordMsgNoUsername):
+# String is the login's hostname.
+rememberPasswordMsgNoUsername = Hoffech chi gofio'r cyfrinair ar %S?
+# LOCALIZATION NOTE (noUsernamePlaceholder):
+# This is displayed in place of the username when it is missing.
+noUsernamePlaceholder=Dim enw defnyddiwr
+togglePasswordLabel=Dangos cyfrineiriau
+togglePasswordAccessKey2=d
+notNowButtonText = &Nid Nawr
+neverForSiteButtonText = &Byth ar Gyfer y Wefan yma
+rememberButtonText = &Cofio
+passwordChangeTitle = Cadarnhau Newid Cyfrinair
+# LOCALIZATION NOTE (updatePasswordMsg):
+# String is the username for the login.
+updatePasswordMsg = Hoffech chi ddiweddaru cyfrinair "%S"?
+updatePasswordMsgNoUser = Hoffech chi ddiweddaru'r cyfrinair?
+userSelectText2 = Dewis pa fewngofnod i'w ddiweddaru:
+loginsDescriptionAll2=Mae'r cyfrineiriau ar gyfer y gwefannau hyn ar gadw ar eich cyfrifiadur
+
+# LOCALIZATION NOTE (useASecurelyGeneratedPassword):
+# Shown in the autocomplete popup to allow filling a generated password into a password field.
+useASecurelyGeneratedPassword=Defnyddiwch Gyfrinair sydd wedi ei Gynhyrchu'n Ddiogel
+# LOCALIZATION NOTE (generatedPasswordWillBeSaved):
+# %S will contain the brandShorterName. This informs the user that the generated password will be automatically saved.
+generatedPasswordWillBeSaved=Bydd %S yn cadw'r cyfrinair hwn ar gyfer y wefan hon.
+# LOCALIZATION NOTE (loginHostAge):
+# This is used to show the context menu login items with their age.
+# 1st string is the username for the login, 2nd is the login's age.
+loginHostAge=%1$S (%2$S)
+# LOCALIZATION NOTE (noUsername):
+# String is used on the context menu when a login doesn't have a username.
+noUsername=Dim enw defnyddiwr
+
+# LOCALIZATION NOTE (displaySameOrigin):
+# String is used on the autocomplete row when the login origin is a domain match with the document origin
+displaySameOrigin=O'r wefan hon
+
+# LOCALIZATION NOTE (insecureFieldWarningDescription2):
+# %1$S will contain insecureFieldWarningLearnMore and look like a link to indicate that clicking will open a tab with support information.
+insecureFieldWarningDescription2 = Nid yw'r cysylltiad yn ddiogel. Gall fewngofnodion sydd wedi eu rhoi yma gael eu cyfaddawdu. %1$S
+insecureFieldWarningLearnMore = Dysgu Rhagor
+
+# LOCALIZATION NOTE (viewSavedLogins.label):
+# This label is used in the footer of login autocomplete menus.
+viewSavedLogins.label= Gweld Mewngofnodion wedi eu Cadw
diff --git a/l10n-cy/toolkit/chrome/places/places.properties b/l10n-cy/toolkit/chrome/places/places.properties
new file mode 100644
index 0000000000..d45a16db4e
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/places/places.properties
@@ -0,0 +1,33 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+BookmarksMenuFolderTitle=Dewislen Nodau Tudalen
+BookmarksToolbarFolderTitle=Bar Offer Nodau Tudalen
+OtherBookmarksFolderTitle=Nodau Tudalen Eraill
+TagsFolderTitle=Tagiau
+MobileBookmarksFolderTitle=Nodau Tudalen Symudol
+
+OrganizerQueryHistory=Hanes
+OrganizerQueryDownloads=Llwythi
+OrganizerQueryAllBookmarks=Pob Nod Tudalen
+
+# LOCALIZATION NOTE (dateName):
+# These are used to generate history containers when history is grouped by date
+finduri-AgeInDays-is-0=Heddiw
+finduri-AgeInDays-is-1=Ddoe
+finduri-AgeInDays-is=%S diwrnod yn ôl
+finduri-AgeInDays-last-is=Y %S diwrnod diwethaf
+finduri-AgeInDays-isgreater=Hŷn na %S diwrnod
+finduri-AgeInMonths-is-0=Y mis yma
+finduri-AgeInMonths-isgreater=Hŷn na %S mis
+
+# LOCALIZATION NOTE (localFiles):
+# This is used to generate local files container when history is grouped by site
+localhost=(ffeiliau lleol)
+
+# LOCALIZATION NOTE
+# The string is used for showing file size of each backup in the "fileRestorePopup" popup
+# %1$S is the file size
+# %2$S is the file size unit
+backupFileSizeText=%1$S %2$S
diff --git a/l10n-cy/toolkit/chrome/pluginproblem/pluginproblem.dtd b/l10n-cy/toolkit/chrome/pluginproblem/pluginproblem.dtd
new file mode 100644
index 0000000000..b4e2581aaf
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/pluginproblem/pluginproblem.dtd
@@ -0,0 +1,33 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<!-- LOCALIZATION NOTE (tapToPlayPlugin): Mobile (used for touch interfaces) only has one type of plugin possible. -->
+
+<!ENTITY tapToPlayPlugin                                     "Cliciwch yma i gychwyn yr ategyn.">
+<!ENTITY clickToActivatePlugin                               "Gweithredu'r ategyn.">
+<!ENTITY checkForUpdates                                     "Gwirio am ddiweddariadau…">
+<!ENTITY blockedPlugin.label                                 "Mae'r ategyn wedi ei rwystro er eich diogelwch.">
+<!ENTITY hidePluginBtn.label                                 "Cuddio ategyn">
+<!ENTITY managePlugins                                       "Rheoli ategion…">
+
+<!-- LOCALIZATION NOTE (reloadPlugin.pre): include a trailing space as needed -->
+<!-- LOCALIZATION NOTE (reloadPlugin.middle): avoid leading/trailing spaces, this text is a link -->
+<!-- LOCALIZATION NOTE (reloadPlugin.post): include a starting space as needed -->
+
+<!ENTITY reloadPlugin.pre                                    "">
+<!ENTITY reloadPlugin.middle                                 "Ail lwytho'r dudalen">
+<!ENTITY reloadPlugin.post                                   " i geisio eto.">
+<!-- LOCALIZATION NOTE (report.please): This and the other report.* strings should be as short as possible, ideally 2-3 words. -->
+<!ENTITY report.please                                       "Anfon adroddiad chwalu">
+<!ENTITY report.submitting                                   "Anfon yr adroddiad…">
+<!ENTITY report.submitted                                    "Wedi anfon adroddiad chwalu.">
+<!ENTITY report.disabled                                     "Adrodd ar chwalu wedi ei analluogi.">
+<!ENTITY report.failed                                       "Cyflwyno wedi methu.">
+<!ENTITY report.unavailable                                  "Dim adroddiad ar gael.">
+<!ENTITY report.comment                                      "Ychwanegu sylw (sylwadau yn weladwy'n gyhoeddus)">
+<!ENTITY report.pageURL                                      "Cynnwys URL y dudalen">
+
+<!ENTITY plugin.file                                         "Ffeil">
+<!ENTITY plugin.mimeTypes                                    "Math MIME">
+<!ENTITY plugin.flashProtectedMode.label                     "Galluogi modd diogel Adobe Flash">
+<!ENTITY plugin.enableBlocklists.label                       "Rhwystro cynnwys Flash peryglus ac ymwthiol">
diff --git a/l10n-cy/toolkit/chrome/search/search.properties b/l10n-cy/toolkit/chrome/search/search.properties
new file mode 100644
index 0000000000..c40297c1d4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/search/search.properties
@@ -0,0 +1,19 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addEngineConfirmTitle=Ychwanegu Peiriant Chwilio
+addEngineConfirmation=Ychwanegu "%S" i'r rhestr o beiriannau chwilio sydd ar gael yn y bar chwilio?\n\nO: %S
+addEngineAsCurrentText=Gwneud hwn y peiriant chwilio c&yfredol
+addEngineAddButtonLabel=Ychwanegu
+
+error_loading_engine_title=Gwall llwytho i lawr
+# LOCALIZATION NOTE (error_loading_engine_msg2): %1$S = brandShortName, %2$S = location
+error_loading_engine_msg2=Methodd %S â llwytho i lawr yr ategyn chwilio o:\n%S
+error_duplicate_engine_msg=Methodd %S â gosod yr ategyn chwilio o "%S" gan fod peiriant chwilio sydd â'r un enw yn bodoli'n barod.
+
+error_invalid_engine_title=Gwall Gosod
+error_invalid_format_title=Fformat Annilys
+# LOCALIZATION NOTE (error_invalid_engine_msg2): %1$S = brandShortName, %2$S = location (url)
+error_invalid_engine_msg2=Nid yw %1$S yn gallu gosod y peiriant chwilio o %2$S
+
diff --git a/l10n-cy/toolkit/crashreporter/aboutcrashes.ftl b/l10n-cy/toolkit/crashreporter/aboutcrashes.ftl
new file mode 100644
index 0000000000..1cc78a899b
--- /dev/null
+++ b/l10n-cy/toolkit/crashreporter/aboutcrashes.ftl
@@ -0,0 +1,31 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v- 2-0- If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla-org/MPL/2-0/-
+
+
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+crash-reports-title = Adroddiadau Chwalu
+
+submit-all-button-label = Cyflwyno Popeth
+delete-button-label = Clirio Popeth
+delete-confirm-title = Ydych chi'n siŵr?
+delete-unsubmitted-description = Bydd hyn yn dileu pob adroddiad chwalu heb eu cyflwyno ac nid oes modd ei ddadwneud.
+delete-submitted-description = Bydd hyn yn dileu'r rhestr o adroddiadau chwalu sydd wedi eu cyflwyno ond ni bydd yn dileu'r data sydd wedi ei gyflwyno. Nid oes modd dadwneud hyn.
+
+crashes-unsubmitted-label = Adroddiadau Chwalu heb eu Cyflwyno
+id-heading = Enw'r Adroddiad
+date-crashed-heading = Dyddiad y Chwalu
+submit-crash-button-label = Cyflwyno
+# This text is used to replace the label of the crash submit button
+# if the crash submission fails.
+submit-crash-button-failure-label = Methiant
+
+crashes-submitted-label = Adroddiadau Chwalu
+date-submitted-heading = Dyddiad Cyflwynwyd
+view-crash-button-label = Golwg
+
+no-reports-label = Does dim adroddiadau chwalu wedi eu cyflwyno.
+no-config-label = Mae'r rhaglen wedi ei ffurfweddu i ddangos adroddiadau chwalu. Rhaid gosod y <code>breakpad.reportURL</code>.
diff --git a/l10n-cy/toolkit/crashreporter/crashreporter.ini b/l10n-cy/toolkit/crashreporter/crashreporter.ini
new file mode 100644
index 0000000000..eafedbbd4d
--- /dev/null
+++ b/l10n-cy/toolkit/crashreporter/crashreporter.ini
@@ -0,0 +1,60 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This file is in the UTF-8 encoding
+[Strings]
+# LOCALIZATION NOTE (isRTL):
+# Leave this entry empty unless your language requires right-to-left layout,
+# for example like Arabic, Hebrew, Persian. If your language needs RTL, please
+# use the untranslated English word "yes" as value
+isRTL=
+CrashReporterTitle=Adroddwr Chwalu
+# LOCALIZATION NOTE (CrashReporterVendorTitle): %s is replaced with the vendor name.  (i.e. "Mozilla")
+CrashReporterVendorTitle=Adroddwr Chwalu %s
+# LOCALIZATION NOTE (CrashReporterErrorText): %s is replaced with another string containing detailed information.
+CrashReporterErrorText=Profodd y rhaglen anhawster ac mae wedi chwalu.\n\nYn anffodus, nid yw'r adroddwr chwalu yn gallu cyflwyno adroddiad am y chwalfa.\n\nManylion: %s
+# LOCALIZATION NOTE (CrashReporterProductErrorText2): The first %s is replaced with the product name (i.e. "Firefox"), the second is replaced with another string containing detailed information.  These two substitutions can not be reordered!
+CrashReporterProductErrorText2=Profodd %s anhawster ac mae wedi chwalu.\n\nYn anffodus, nid yw'r adroddwr chwalu yn medru cyflwyno adroddiad chwalu.\n\nManylion: %s
+CrashReporterSorry=Ymddiheuriadau
+# LOCALIZATION NOTE (CrashReporterDescriptionText2): The %s is replaced with the product name.
+CrashReporterDescriptionText2=Profodd %s anhawster ac mae wedi chwalu.\n\nI'n cynorthwyo i ddatrys yr anhawster, anfonwch adroddiad gwall atom.
+CrashReporterDefault=Mae'r rhaglen yn cael ei rhedeg ar ôl chwalfa er mwyn adrodd ar anhawster i ddarparwr y rhaglen.  Ni ddylai gael ei redeg yn uniongyrchol.
+Details=Manylion…
+ViewReportTitle=Cynnwys yr Adroddiad
+CommentGrayText=Ychwanegu sylw (sylwadau yn weladwy'n gyhoeddus)
+ExtraReportInfo=Mae'r adroddiad hefyd yn cynnwys gwybodaeth dechnegol am gyflwr y rhaglen wrth iddi chwalu.
+# LOCALIZATION NOTE (CheckSendReport): The %s is replaced with the vendor name.
+CheckSendReport=Dweud wrth %s am y chwalfa fel bod modd ei drwsio
+CheckIncludeURL=Cynnwys cyfeiriad y dudalen roeddwn arni
+CheckAllowEmail=Gadael i %s gysylltu â mi am yr adroddiad
+EmailGrayText=Rhowch eich cyfeiriad e-bost yma
+ReportPreSubmit2=Bydd eich adroddiad chwalu yn cael ei gyflwyno cyn i chi adael neu ail gychwyn.
+ReportDuringSubmit2=Cyflwyno eich adroddiad…
+ReportSubmitSuccess=Adroddiad wedi ei gyflwyno'n llwyddiannus!
+ReportSubmitFailed=Bu anhawster wrth gyflwyno eich adroddiad.
+ReportResubmit=Ail anfon adroddiadau fethwyd eu hanfon yn y gorffennol…
+# LOCALIZATION NOTE (Quit2): The %s is replaced with the product name.
+Quit2=Gadael %s
+# LOCALIZATION NOTE (Restart): The %s is replaced with the product name.
+Restart=Ailgychwyn %s
+Ok=Iawn
+Close=Cau
+
+# LOCALIZATION NOTE (CrashID): The %s is replaced with the Crash ID from the server, which is a string like abc12345-6789-0abc-def1-23456abcdef1
+CrashID=Enw Chwalfa: %s
+# LOCALIZATION NOTE (CrashDetailsURL): The %s is replaced with a URL that the user can visit to view the crash details.
+CrashDetailsURL=Mae modd gweld manylion y chwalu yn %s
+ErrorBadArguments=Mae'r rhaglen wedi mynegi ymresymiad annilys.
+ErrorExtraFileExists=Nid yw'r rhaglen wedi gadael ffeil data rhaglen.
+ErrorExtraFileRead=Methu darllen ffeil data'r rhaglen.
+ErrorExtraFileMove=Methu symud ffeil data'r rhaglen.
+ErrorDumpFileExists=Nid yw'r rhaglen wedi gadel ffeil swp chwalu.
+ErrorDumpFileMove=Methu symud swp chwalu.
+ErrorNoProductName=Nid yw'r rhaglen wedi amlygu ei hun.
+ErrorNoServerURL=Nid yw'r rhaglen wedi enwi gweinydd adrodd chwalu.
+ErrorNoSettingsPath=Methu canfod gosodiadau'r adroddwr chwalu.
+ErrorCreateDumpDir=Methu creu cyfeiriadur swp disgwylgar.
+# LOCALIZATION NOTE (ErrorEndOfLife): The %s is replaced with the product name.
+ErrorEndOfLife=Nid yw'r fersiwn o %s rydych yn ei ddefnyddio'n cael ei gynnal bellach. Nid yw adroddiadau chwalu'n cael eu derbyn bellach o'r fersiwn yma. Ystyriwch ddiweddaru i fersiwn sy'n cael ei gynnal.
+
diff --git a/l10n-cy/toolkit/defines.inc b/l10n-cy/toolkit/defines.inc
new file mode 100644
index 0000000000..7121d25835
--- /dev/null
+++ b/l10n-cy/toolkit/defines.inc
@@ -0,0 +1 @@
+#define MOZ_LANG_TITLE Cymraeg
diff --git a/l10n-cy/toolkit/toolkit/about/aboutAbout.ftl b/l10n-cy/toolkit/toolkit/about/aboutAbout.ftl
new file mode 100644
index 0000000000..9c93e1bcd7
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutAbout.ftl
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-about-title = About About
+about-about-note =
+    Dyma restr o dudalennau “about” er hwylustod.<br/>
+    Gall rhai ohonynt fod yn ddryslyd. Mae rhai ar gyfer pwrpas canfod gwallau yn unig.<br/>
+    Ac mae rhai ar goll am fod angen llinyn ymholiad arnynt.
diff --git a/l10n-cy/toolkit/toolkit/about/aboutAddons.ftl b/l10n-cy/toolkit/toolkit/about/aboutAddons.ftl
new file mode 100644
index 0000000000..26b6c9bdd2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutAddons.ftl
@@ -0,0 +1,431 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addons-window =
+    .title = Rheolwr Ychwanegion
+addons-page-title = Rheolwr Ychwanegion
+search-header =
+    .placeholder = Search addons.mozilla.org
+    .searchbuttonlabel = Chwilio
+search-header-shortcut =
+    .key = f
+list-empty-installed =
+    .value = Nid oes gennych ychwanegion o'r math yma wedi eu gosod
+list-empty-available-updates =
+    .value = Heb ganfod diweddariadau
+list-empty-recent-updates =
+    .value = Nid ydych wedi diweddaru eich ychwanegion yn ddiweddar
+list-empty-find-updates =
+    .label = Gwirio am Ddiweddariadau
+list-empty-button =
+    .label = Dysgu rhagor am ychwanegion
+help-button = Cefnogaeth Ychwanegion
+sidebar-help-button-title =
+    .title = Cefnogaeth Ychwanegion
+preferences =
+    { PLATFORM() ->
+        [windows] Dewisiadau { -brand-short-name }
+       *[other] Dewisiadau { -brand-short-name }
+    }
+sidebar-preferences-button-title =
+    .title =
+        { PLATFORM() ->
+            [windows] Dewisiadau { -brand-short-name }
+           *[other] Dewisiadau { -brand-short-name }
+        }
+show-unsigned-extensions-button =
+    .label = Nid oedd modd dilysu rhai estyniadau
+show-all-extensions-button =
+    .label = Dangos pob estyniad
+cmd-show-details =
+    .label = Dangos Rhagor o Wybodaeth
+    .accesskey = D
+cmd-find-updates =
+    .label = Canfod Diweddariadau
+    .accesskey = C
+cmd-preferences =
+    .label =
+        { PLATFORM() ->
+            [windows] Dewisiadau
+           *[other] Dewisiadau
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [windows] D
+           *[other] e
+        }
+cmd-enable-theme =
+    .label = Gwisgo Thema
+    .accesskey = w
+cmd-disable-theme =
+    .label = Peidio Gwisgo Thema
+    .accesskey = P
+cmd-install-addon =
+    .label = Gosod
+    .accesskey = G
+cmd-contribute =
+    .label = Cyfrannu
+    .accesskey = C
+    .tooltiptext = Cyfrannu i ddatblygiad yr ychwanegyn
+detail-version =
+    .label = Fersiwn
+detail-last-updated =
+    .label = Diweddarwyd Diwethaf
+detail-contributions-description = Mae datblygwr yr ychwanegyn yn gofyn eich bod yn cynorthwyo i gefnogi datblygiad drwy wneud cyfraniad bychan.
+detail-contributions-button = Cyfrannu
+    .title = Cyfrannwch i ddatblygiad yr ategyn hwn
+    .accesskey = C
+detail-update-type =
+    .value = Diweddariadau Awtomatig
+detail-update-default =
+    .label = Rhagosodedig
+    .tooltiptext = Gosod diweddariadau'n awtomatig os mai dyna yw'r rhagosodedig
+detail-update-automatic =
+    .label = Ymlaen
+    .tooltiptext = Gosod diweddariadau'n awtomatig
+detail-update-manual =
+    .label = Diffodd
+    .tooltiptext = Peidio gosod diweddariadau'n awtomatig
+# Used as a description for the option to allow or block an add-on in private windows.
+detail-private-browsing-label = Rhedeg mewn Ffenestri Preifat
+# Some add-ons may elect to not run in private windows by setting incognito: not_allowed in the manifest.  This
+# cannot be overridden by the user.
+detail-private-disallowed-label = Heb ei ganiatáu mewn Ffenestri Preifat
+detail-private-disallowed-description2 = Nid yw'r estyniad hwn yn rhedeg tra'n pori'n preifat. <a data-l10n-name="learn-more">Dysgu rhagor</a>
+# Some special add-ons are privileged, run in private windows automatically, and this permission can't be revoked
+detail-private-required-label = Angen Mynediad i Ffenestri Preifat
+detail-private-required-description2 = Mae gan yr estyniad hwn fynediad i'ch gweithgareddau ar-lein wrth bori'n breifat. <a data-l10n-name="learn-more">Dysgu mwy</a>
+detail-private-browsing-on =
+    .label = Caniatáu
+    .tooltiptext = Caniatáu wrth Bori Preifat
+detail-private-browsing-off =
+    .label = Peidio Caniatáu
+    .tooltiptext = Analluogi mewn Pori Preifat
+detail-home =
+    .label = Tudalen Cartref
+detail-home-value =
+    .value = { detail-home.label }
+detail-repository =
+    .label = Proffil Ychwanegyn
+detail-repository-value =
+    .value = { detail-repository.label }
+detail-check-for-updates =
+    .label = Gwirio am Ddiweddariadau
+    .accesskey = G
+    .tooltiptext = Gwirio am ddiweddariad i'r ychwanegyn
+detail-show-preferences =
+    .label =
+        { PLATFORM() ->
+            [windows] Dewisiadau
+           *[other] Dewisiadau
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [windows] D
+           *[other] e
+        }
+    .tooltiptext =
+        { PLATFORM() ->
+            [windows] Newid dewisiadau'r ychwanegyn
+           *[other] Newid dewisiadau'r ychwanegyn
+        }
+detail-rating =
+    .value = Graddio
+addon-restart-now =
+    .label = Ailgychwyn nawr
+disabled-unsigned-heading =
+    .value = Mae rhai ychwanegion wedi eu hanalluogi
+disabled-unsigned-description = Mae'r ychwanegion canlynol wedi eu dilysu i'w defnyddio yn { -brand-short-name }. Gallwch <label data-l10n-name="find-addons">canfod newidiadau</label> neu ofyn i'r datblygwr iddynt gael eu dilysu.
+disabled-unsigned-learn-more = Dysgu rhagor am ein hymdrechion i'ch cadw'n ddiogel ar-lein.
+disabled-unsigned-devinfo = Gall ddatblygwyr sydd â diddordeb mewn dilysu eu hychwanegion barhau drwy ddarllen ein <label data-l10n-name="learn-more">canllawiau</label>.
+plugin-deprecation-description = Rhywbeth ar goll? Nid yw rhai ategion yn cael eu cynnal bellach gan { -brand-short-name }. <label data-l10n-name="learn-more">Dysgu Rhagor.</label>
+legacy-warning-show-legacy = Dangos hen estyniadau
+legacy-extensions =
+    .value = Hen Estyniadau
+legacy-extensions-description = Nid yw'r estyniadau hyn yn cyrraedd safonau cyfredol { -brand-short-name } ac mae nhw wedi cael eu diffodd. <label data-l10n-name="legacy-learn-more">Dysgu am y newidiadau i ychwanegion</label>
+private-browsing-description2 =
+    Mae { -brand-short-name } yn newid sut mae estyniadau'n gweithio o fewn pori preifat. Ni fydd unrhyw estyniadau newydd y byddwch chi'n eu hychwanegu at { -brand-short-name } yn rhedeg yn ragosodedig o fewn Ffenestri Prefat. Oni bai eich bod yn ei ganiatáu yn y gosodiadau, ni fydd estyniad yn gweithio wrth bori'n preifat, ac ni chaiff fynediad at eich gweithgareddau ar-lein yno. Rydym wedi gwneud y newid hwn i gadw eich pori preifat yn breifat.
+    <label data-l10n-name="private-browsing-learn-more">Dysgu sut i reoli gosodiadau estyniad.</label>
+addon-category-discover = Argymhellion
+addon-category-discover-title =
+    .title = Argymhellion
+addon-category-extension = Estyniadau
+addon-category-extension-title =
+    .title = Estyniadau
+addon-category-theme = Themâu
+addon-category-theme-title =
+    .title = Themâu
+addon-category-plugin = Ategion
+addon-category-plugin-title =
+    .title = Ategion
+addon-category-dictionary = Geiriaduron
+addon-category-dictionary-title =
+    .title = Geiriaduron
+addon-category-locale = Iaith
+addon-category-locale-title =
+    .title = Iaith
+addon-category-available-updates = Diweddariadau ar Gael
+addon-category-available-updates-title =
+    .title = Diweddariadau ar Gael
+addon-category-recent-updates = Diweddariadau Diweddar
+addon-category-recent-updates-title =
+    .title = Diweddariadau Diweddar
+
+## These are global warnings
+
+extensions-warning-safe-mode = Mae pob ychwanegyn wedi eu hanalluogi gan y modd diogel.
+extensions-warning-check-compatibility = Mae gwirio cydnawsedd ychwanegion wedi ei analluogi. Efallai fod gennych ychwanegion anghydnaws.
+extensions-warning-check-compatibility-button = Galluogi
+    .title = Galluogi gwirio cydnawsedd ychwanegion
+extensions-warning-update-security = Mae gwirio diogelwch diweddariad wedi ei analluogi. Efallai eich bod o dan fygythiad gan ddiweddariad.
+extensions-warning-update-security-button = Galluogi
+    .title = Galluogi gwirio diogelwch diweddariad ychwanegyn
+
+## Strings connected to add-on updates
+
+addon-updates-check-for-updates = Gwirio am Ddiweddariadau
+    .accesskey = G
+addon-updates-view-updates = Gweld Diweddariadau Diweddar
+    .accesskey = D
+
+# This menu item is a checkbox that toggles the default global behavior for
+# add-on update checking.
+
+addon-updates-update-addons-automatically = Diweddaru Ychwanegion yn Awtomatig
+    .accesskey = A
+
+## Specific add-ons can have custom update checking behaviors ("Manually",
+## "Automatically", "Use default global behavior"). These menu items reset the
+## update checking behavior for all add-ons to the default global behavior
+## (which itself is either "Automatically" or "Manually", controlled by the
+## extensions-updates-update-addons-automatically.label menu item).
+
+addon-updates-reset-updates-to-automatic = Ailosod Pob Ychwanegyn i'w Diweddaru'n Awtomatig
+    .accesskey = P
+addon-updates-reset-updates-to-manual = Ailosod Pob Ychwanegyn i Ddiweddaru gyda Llaw
+    .accesskey = L
+
+## Status messages displayed when updating add-ons
+
+addon-updates-updating = Diweddaru ychwanegion
+addon-updates-installed = Mae eich ychwanegion wedi eu diweddaru.
+addon-updates-none-found = Heb ganfod diweddariadau
+addon-updates-manual-updates-found = Gweld Diweddariadau ar Gael
+
+## Add-on install/debug strings for page options menu
+
+addon-install-from-file = Gosod Ychwanegyn o Ffeil…
+    .accesskey = G
+addon-install-from-file-dialog-title = Dewis ategyn i'w osod
+addon-install-from-file-filter-name = Ychwanegion
+addon-open-about-debugging = Dadfygio Ychwanegion
+    .accesskey = Y
+
+## Extension shortcut management
+
+# This is displayed in the page options menu
+addon-manage-extensions-shortcuts = Rheoli Estyniad Llwybrau Byr
+    .accesskey = R
+shortcuts-no-addons = Nid oes gennych unrhyw estyniadau wedi'u galluogi.
+shortcuts-no-commands = Nid oes gan yr estyniadau canlynol lwybrau byr:
+shortcuts-input =
+    .placeholder = Teipiwch llwybr byr
+shortcuts-browserAction2 = Cychwyn botwm bar offer
+shortcuts-pageAction = Cychwyn gweithred tudalen
+shortcuts-sidebarAction = Toglo'r bar ochr
+shortcuts-modifier-mac = Cynnwys Ctrl, Alt, neu ⌘
+shortcuts-modifier-other = Cynnwys Ctrl neu Alt
+shortcuts-invalid = Cyfuniad annilys
+shortcuts-letter = Teipiwch lythyr
+shortcuts-system = Methu anwybyddu llwybr byr { -brand-short-name }
+# String displayed in warning label when there is a duplicate shortcut
+shortcuts-duplicate = Llwybr byr dyblyg
+# String displayed when a keyboard shortcut is already assigned to more than one add-on
+# Variables:
+#   $shortcut (string) - Shortcut string for the add-on
+shortcuts-duplicate-warning-message = Mae { $shortcut } yn cael ei ddefnyddio fel llwybr byr mewn mwy nag un achos. Gall llwybrau byr dyblyg achosi ymddygiad annisgwyl.
+# String displayed when a keyboard shortcut is already used by another add-on
+# Variables:
+#   $addon (string) - Name of the add-on
+shortcuts-exists = Ar waith eisoes gan { $addon }
+shortcuts-card-expand-button =
+    { $numberToShow ->
+        [zero] Dangos { $numberToShow } yn Rhagor
+        [one] Dangos { $numberToShow } yn Rhagor
+        [two] Dangos { $numberToShow } yn Rhagor
+        [few] Dangos { $numberToShow } yn Rhagor
+        [many] Dangos { $numberToShow } yn Rhagor
+       *[other] Dangos { $numberToShow } yn Rhagor
+    }
+shortcuts-card-collapse-button = Dangos Llai
+header-back-button =
+    .title = Mynd nôl
+
+## Recommended add-ons page
+
+# Explanatory introduction to the list of recommended add-ons. The action word
+# ("recommends") in the final sentence is a link to external documentation.
+discopane-intro =
+    Mae estyniadau a themâu yn debyg i apiau ar gyfer eich porwr, ac maen nhw'n gadael i chi
+    diogelu cyfrineiriau, llwytho fideos i lawr, dod o hyd i gytundebau, rhwystro hysbysebion blin, newid
+    golwg eich porwr a llawer mwy. Mae'r rhaglenni meddalwedd bach hyn fel arfer yn cael eu datblygu gan drydydd parti. Dyma detholiad y mae { -brand-product-name }<a data-l10n-name="learn-more-trigger">
+    yn eu hargymell </a> am ddiogelwch, perfformiad, a swyddogaethau gwell.
+# Notice to make user aware that the recommendations are personalized.
+discopane-notice-recommendations =
+    Mae rhai o'r argymhellion hyn wedi'u dewis yn benodol ar eich cyfer chi. Maen nhw'n seiliedig ar 
+    estyniadau eraill rydych chi wedi'u gosod, eich proffil dewisiadau, a'ch ystadegau defnydd.
+discopane-notice-learn-more = Dysgu rhagor
+privacy-policy = Polisi Preifatrwydd
+# Refers to the author of an add-on, shown below the name of the add-on.
+# Variables:
+#   $author (string) - The name of the add-on developer.
+created-by-author = gan <a data-l10n-name="author">{ $author }</a>
+# Shows the number of daily users of the add-on.
+# Variables:
+#   $dailyUsers (number) - The number of daily users.
+user-count = Defnyddwyr: { $dailyUsers }
+install-extension-button = Ychwanegu at { -brand-product-name }
+install-theme-button = Gosod Thema
+# The label of the button that appears after installing an add-on. Upon click,
+# the detailed add-on view is opened, from where the add-on can be managed.
+manage-addon-button = Rheoli
+find-more-addons = Canfod rhagor o ychwanegion
+# This is a label for the button to open the "more options" menu, it is only
+# used for screen readers.
+addon-options-button =
+    .aria-label = Rhagor o Ddewisiadau
+
+## Add-on actions
+
+report-addon-button = Adrodd
+remove-addon-button = Tynnu
+# The link will always be shown after the other text.
+remove-addon-disabled-button = Methu ei Dynnu <a data-l10n-name="link"> Pam? </a>
+disable-addon-button = Analluogu
+enable-addon-button = Galluogi
+# This is used for the toggle on the extension card, it's a checkbox and this
+# is always its label.
+extension-enable-addon-button-label =
+    .aria-label = Galluogi
+preferences-addon-button =
+    { PLATFORM() ->
+        [windows] Opsiynau
+       *[other] Dewisiadau
+    }
+details-addon-button = Manylion
+release-notes-addon-button = Nodiadau Rhyddhau
+permissions-addon-button = Caniatâd
+extension-enabled-heading = Galluogwyd
+extension-disabled-heading = Analluogwyd
+theme-enabled-heading = Galluogwyd
+theme-disabled-heading = Analluogwyd
+plugin-enabled-heading = Galluogwyd
+plugin-disabled-heading = Analluogwyd
+dictionary-enabled-heading = Galluogwyd
+dictionary-disabled-heading = Analluogwyd
+locale-enabled-heading = Galluogwyd
+locale-disabled-heading = Analluogwyd
+ask-to-activate-button = Gofyn i'w Weithredu
+always-activate-button = Gweithredu Bob Tro
+never-activate-button = Byth Gweithredu
+addon-detail-author-label = Awdur
+addon-detail-version-label = Fersiwn
+addon-detail-last-updated-label = Diweddarwyd Diwethaf
+addon-detail-homepage-label = Tudalen Cartref
+addon-detail-rating-label = Graddio
+# Message for add-ons with a staged pending update.
+install-postponed-message = Bydd yr estyniad hwn yn cael ei ddiweddaru pan fydd { -brand-short-name } yn ailgychwyn.
+install-postponed-button = Diweddaru Nawr
+# The average rating that the add-on has received.
+# Variables:
+#   $rating (number) - A number between 0 and 5. The translation should show at most one digit after the comma.
+five-star-rating =
+    .title = Graddiwyd { NUMBER($rating, maximumFractionDigits: 1) } allan o 5
+# This string is used to show that an add-on is disabled.
+# Variables:
+#   $name (string) - The name of the add-on
+addon-name-disabled = { $name } (analluogwyd)
+# The number of reviews that an add-on has received on AMO.
+# Variables:
+#   $numberOfReviews (number) - The number of reviews received
+addon-detail-reviews-link =
+    { $numberOfReviews ->
+        [zero] { $numberOfReviews } adolygiad
+        [one] { $numberOfReviews } adolygiad
+        [two] { $numberOfReviews } adolygiad
+        [few] { $numberOfReviews } adolygiad
+        [many] { $numberOfReviews } adolygiad
+       *[other] { $numberOfReviews } adolygiad
+    }
+
+## Pending uninstall message bar
+
+# Variables:
+#   $addon (string) - Name of the add-on
+pending-uninstall-description = Mae <span data-l10n-name="addon-name">{ $addon }</span> wedi ei dynnu.
+pending-uninstall-undo-button = Dadwneud
+addon-detail-updates-label = Caniatáu diweddariadau awtomatig
+addon-detail-updates-radio-default = Rhagosodedig
+addon-detail-updates-radio-on = Ymlaen
+addon-detail-updates-radio-off = Diffodd
+addon-detail-update-check-label = Gwirio am Ddiweddariadau
+install-update-button = Diweddaru
+# This is the tooltip text for the private browsing badge in about:addons. The
+# badge is the private browsing icon included next to the extension's name.
+addon-badge-private-browsing-allowed2 =
+    .title = Caniatáu mewn ffenestri preifat
+    .aria-label = { addon-badge-private-browsing-allowed2.title }
+addon-detail-private-browsing-help = Pan mae'n cael ei ganiatáu, bydd yr estyniad ar gael i'ch gweithgareddau ar-lein tra byddwch yn pori'n breifat. <a data-l10n-name="learn-more"> Gwybod rhagor</a>
+addon-detail-private-browsing-allow = Caniatáu
+addon-detail-private-browsing-disallow = Peidio Caniatáu
+
+## This is the tooltip text for the recommended badges for an extension in about:addons. The
+## badge is a small icon displayed next to an extension when it is recommended on AMO.
+
+addon-badge-recommended2 =
+    .title = Dim ond estyniadau sy'n cwrdd â'n safonau ar gyfer diogelwch a pherfformiad y mae { -brand-product-name } yn eu hargymell
+    .aria-label = { addon-badge-recommended2.title }
+addon-badge-line2 =
+    .title = Crëwyd yr estyniad swyddogol hwn gan wneuthurwyr { -brand-product-name }
+    .aria-label = { addon-badge-line2.title }
+# We hard code "Mozilla" in the string below because the extensions are built
+# by Mozilla and we don't want forks to display "by Fork".
+addon-badge-line3 =
+    .title = Estyniad swyddogol wedi'i adeiladu gan Mozilla. Mae'n cydfynd â safonau diogelwch a pherfformiad
+    .aria-label = { addon-badge-line3.title }
+addon-badge-verified2 =
+    .title = Mae'r estyniad hwn wedi'i adolygu i fodloni ein safonau ar gyfer diogelwch a pherfformiad
+    .aria-label = { addon-badge-verified2.title }
+
+##
+
+available-updates-heading = Diweddariadau ar Gael
+recent-updates-heading = Diweddariadau Diweddar
+release-notes-loading = Llwytho…
+release-notes-error = Ymddiheuriadau ond bu gwall llwytho'r nodiadau ryddhau.
+addon-permissions-empty = Nid oes angen unrhyw ganiatâd ar yr estyniad hwn
+addon-permissions-required = Caniatâd angenrheidiol y swyddogaethau craidd:
+addon-permissions-optional = Caniatâd dewisol ar gyfer y swyddogaethau ychwanegol:
+addon-permissions-learnmore = Dysgu rhagor am ganiatâd
+recommended-extensions-heading = Estyniadau Cymeradwy
+recommended-themes-heading = Themâu Cymeradwy
+# A recommendation for the Firefox Color theme shown at the bottom of the theme
+# list view. The "Firefox Color" name itself should not be translated.
+recommended-theme-1 = Teimlo'n greadigol? <a data-l10n-name="link">Adeiladwch eich thema eich hun gyda Firefox Color. </a>
+
+## Page headings
+
+extension-heading = Rheoli eich estyniadau
+theme-heading = Rheoli eich themâu
+plugin-heading = Rheoli eich ategion
+dictionary-heading = Rheoli eich geiriaduron
+locale-heading = Rheoli eich ieithoedd
+updates-heading = Rheoli Eich Diweddariadau
+discover-heading = Personoli Eich { -brand-short-name }
+shortcuts-heading = Rheoli Estyniad Llwybrau Byr
+default-heading-search-label = Canfod rhagor o ychwanegion
+addons-heading-search-input =
+    .placeholder = Search addons.mozilla.org
+addon-page-options-button =
+    .title = Offer ar gyfer pob ychwanegyn
diff --git a/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl b/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl
new file mode 100644
index 0000000000..e4e3ee332e
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+label-disable = analluogi
+label-enable = Galluogi
+label-interventions = Ymyriadau
+label-more-information = Rhagor o Wybodaeth: Byg { $bug }
+label-overrides = Tros reolaeth Asiant Defnyddiwr
+text-disabled-in-about-config = Mae'r nodwedd hon wedi ei analluogi yn about:config
+text-no-interventions = Nid oes ymyriadau yn cael eu defnyddio
+text-no-overrides = Nid oes unrhyw ymyriadau UA yn cael eu defnyddio
+text-title = about:compat
diff --git a/l10n-cy/toolkit/toolkit/about/aboutConfig.ftl b/l10n-cy/toolkit/toolkit/about/aboutConfig.ftl
new file mode 100644
index 0000000000..dfbe5f46fa
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutConfig.ftl
@@ -0,0 +1,109 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+config-window =
+    .title = about:config
+
+## Strings used to display a warning in about:config
+
+# This text should be attention grabbing and playful
+config-about-warning-title =
+    .value = Gall hyn ddiddymu eich gwarant!
+config-about-warning-text = Gall newid y gosodiadau uwch wneud niwed i sefydlogrwydd a pherfformiad y rhaglen. Dylech barhau dim ond os ydych yn gwybod beth rydych yn ei wneud.
+config-about-warning-button =
+    .label = Rwy'n deall y peryglon!
+config-about-warning-checkbox =
+    .label = Dangos y rhybudd y tro nesaf
+
+config-search-prefs =
+    .value = Chwilio:
+    .accesskey = C
+
+config-focus-search =
+    .key = r
+
+config-focus-search-2 =
+    .key = f
+
+## These strings are used for column headers
+
+config-pref-column =
+    .label = Enw'r Dewis
+config-lock-column =
+    .label = Statws
+config-type-column =
+    .label = Math
+config-value-column =
+    .label = Gwerth
+
+## These strings are used for tooltips
+
+config-pref-column-header =
+    .tooltip = Clicio i'w trefnu
+config-column-chooser =
+    .tooltip = Cliciwch i ddewis colofnau i'w dangos
+
+## These strings are used for the context menu
+
+config-copy-pref =
+    .key = C
+    .label = Copïo
+    .accesskey = C
+
+config-copy-name =
+    .label = Copïo Enw
+    .accesskey = n
+
+config-copy-value =
+    .label = Copïo Gwerth
+    .accesskey = G
+
+config-modify =
+    .label = Newid
+    .accesskey = e
+
+config-toggle =
+    .label = Toglo
+    .accesskey = T
+
+config-reset =
+    .label = Ailosod
+    .accesskey = A
+
+config-new =
+    .label = Newydd
+    .accesskey = N
+
+config-string =
+    .label = Llinyn
+    .accesskey = L
+
+config-integer =
+    .label = Cyfanrif
+    .accesskey = i
+
+config-boolean =
+    .label = Booleaidd
+    .accesskey = B
+
+config-default = rhagosodiad
+config-modified = newidwyd
+config-locked = cloi
+
+config-property-string = llinyn
+config-property-int = cyfanrif
+config-property-bool = booleaidd
+
+config-new-prompt = Rhoi enw blaenoriaeth
+
+config-nan-title = Gwerth annilys
+config-nan-text = Nid yw'r testun a gyflwynwyd yn rif.
+
+# Variables:
+#   $type (String): type of value (boolean, integer or string)
+config-new-title = Gwerth newydd { $type }
+
+# Variables:
+#   $type (String): type of value (boolean, integer or string)
+config-modify-title = Rhoi gwerth { $type }
diff --git a/l10n-cy/toolkit/toolkit/about/aboutGlean.ftl b/l10n-cy/toolkit/toolkit/about/aboutGlean.ftl
new file mode 100644
index 0000000000..7c6def3a91
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutGlean.ftl
@@ -0,0 +1,15 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### "Glean" and "Glean SDK" should remain in English.
+
+about-glean-page-title = Ynghylch Glean
+about-glean-description = Mae'r <a data-l10n-name="glean-sdk-doc-link">Glean SDK</a> yn llyfrgell casglu data sy'n cael ei ddefnyddio o fewn cynnyrch Mozilla. Mae'r dudalen hon ar gyfer datblygwyr a phrofwyr sydd angen <a data-l10n-name="fog-debug-doc-link">ffurfweddu dadfygio a chyflwr cofnodi'r Glean SDK </a>.
+about-glean-warning = Gall camddefnyddio'r rhyngwyneb hwn chwalu { -brand-short-name }.
+
+tag-pings-label = Tagiwch bob pingiadau a anfonwyd gyda'r tag hwn
+log-pings-label = Cofnodi llwythi ping cyn anfon?
+send-pings-label = Anfon y ping a enwyd
+controls-button-label = Cyflwyno Gosodiadau
diff --git a/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl b/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl
new file mode 100644
index 0000000000..36ed03dda3
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl
@@ -0,0 +1,28 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-httpsonly-insecure-title = Nid yw'r Cysylltiad Diogel ar Gael
+# Variables:
+#   $websiteUrl (String) - Url of the website that failed to load. Example: www.example.com
+about-httpsonly-insecure-explanation-unavailable = Rydych yn pori yn y modd HTTPS-Only Mode, ac nid oes fersiwn HTTPS ddiogel o <em>{ $websiteUrl }</em> ar gael.
+about-httpsonly-insecure-explanation-reasons = Yn fwyaf tebygol, nid yw'r wefan yn cefnogi HTTPS, ond mae hefyd yn bosibl bod ymosodwr yn rhwystro'r fersiwn HTTPS.
+about-httpsonly-insecure-explanation-exception = Er bod y risg diogelwch yn isel, os penderfynwch ymweld â fersiwn HTTP y wefan, peidiwch nodi unrhyw wybodaeth sensitif fel cyfrineiriau, e-byst, neu fanylion cardiau credyd.
+about-httpsonly-button-make-exception = Derbyn y Risg a Pharhau i'r Wefan
+about-httpsonly-title = Mae { -brand-short-name } wedi canfod Mater Diogelwch Posibl
+# Variables:
+#   $websiteUrl (String) - Url of the website that failed to load. Example: www.example.com
+about-httpsonly-explanation-unavailable = Rydych yn pori yn y modd HTTPS-Only Mode, ac nid oes fersiwn HTTPS ddiogel o <em>{ $websiteUrl }</em> ar gael.
+about-httpsonly-title-alert = Rhybudd Modd HTTPS-yn-Unig
+about-httpsonly-title-connection-not-available = Nid yw'r Cysylltiad Diogel ar Gael
+# Variables:
+#   $websiteUrl (String) - Url of the website that failed to load. Example: www.example.com
+about-httpsonly-explanation-unavailable2 = Rydych wedi galluogi'r Modd HTTPS-yn-Unig ar gyfer gwell diogelwch, ac nid oes fersiwn HTTPS o <em>{ $websiteUrl }</em> ar gael.
+about-httpsonly-explanation-question = Beth allai fod yn achosi hyn?
+about-httpsonly-explanation-nosupport = Yn fwyaf tebygol, nid yw'r wefan yn cefnogi HTTPS.
+about-httpsonly-explanation-risk = Mae hefyd yn bosibl bod ymosodwr yn ceisio ymyrryd. Os penderfynwch ymweld â'r wefan, peidiwch â rhannu unrhyw fanylion sensitif fel cyfrineiriau, e-byst, neu fanylion cardiau credyd.
+about-httpsonly-button-accept-and-continue = Derbyn y Perygl a Pharhau
+about-httpsonly-explanation-continue = Os byddwch yn parhau, bydd y Modd HTTPS-yn-Unig yn cael ei ddiffodd dros dro ar gyfer y wefan hon.
+about-httpsonly-button-continue-to-site = Ymlaen i'r Wefan HTTP
+about-httpsonly-button-go-back = Mynd Nôl
+about-httpsonly-link-learn-more = Dysgu Rhagor…
diff --git a/l10n-cy/toolkit/toolkit/about/aboutMozilla.ftl b/l10n-cy/toolkit/toolkit/about/aboutMozilla.ftl
new file mode 100644
index 0000000000..411039d846
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutMozilla.ftl
@@ -0,0 +1,11 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-mozilla-title-6-27 = Llyfr Mozilla, 6:27
+about-mozilla-quote-6-27 =
+    The Beast continued its studies with renewed <em>Focus</em>, building great <em>Reference</em>
+    works and contemplating new <em>Realities</em>. The Beast brought forth its followers and
+    acolytes to create a renewed smaller form of itself and, through <em>Mischievous</em> means,
+    sent it out across the world.
+about-mozilla-from-6-27 = o <strong>Lyfr Mozilla,</strong> 6:27
diff --git a/l10n-cy/toolkit/toolkit/about/aboutNetworking.ftl b/l10n-cy/toolkit/toolkit/about/aboutNetworking.ftl
new file mode 100644
index 0000000000..f6a1eea82e
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutNetworking.ftl
@@ -0,0 +1,71 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-networking-title = Ynghylch Rhwydweithio
+about-networking-http = HTTP
+about-networking-sockets = Socedi
+about-networking-dns = DNS
+about-networking-dns-clear-cache-button = Clirio'r Storfa DNS
+about-networking-dns-trr-url = URL DoH
+about-networking-dns-suffix = Ôl-ddodiad DNS
+about-networking-websockets = WebSockets
+about-networking-refresh = Adnewyddu
+about-networking-auto-refresh = Adnewyddu pob 3 eiliad
+about-networking-hostname = Enw Gwesteiwr
+about-networking-port = Porth
+about-networking-http-version = Fersiwn HTTP
+about-networking-ssl = SSL
+about-networking-active = Gweithredol
+about-networking-idle = Segur
+about-networking-host = Gwesteiwr
+about-networking-tcp = TCP
+about-networking-sent = Anfonwyd
+about-networking-received = Derbyniwyd
+about-networking-family = Teulu
+about-networking-trr = TRR
+about-networking-addresses = Cyfeiriad
+about-networking-expires = Daw i ben (Eiliadau)
+about-networking-originAttributesSuffix = Allwedd Ynysu
+about-networking-messages-sent = Negeseuon Anfonwyd
+about-networking-messages-received = Negeseuon Derbyniwyd
+about-networking-bytes-sent = Didau Wedi'u Hanfon
+about-networking-bytes-received = Didau Wedi'u Derbyn
+about-networking-logging = Cofnodi
+about-networking-log-tutorial = Gw <a data-l10n-name="logging">HTTP Logging</a> am wybodaeth ar sut i ddefnyddio'r teclyn hwn.
+about-networking-current-log-file = Ffeil Cofnodi Cyfredol:
+about-networking-current-log-modules = Modiwlau Cofnodi Cyfredol:
+about-networking-set-log-file = Gosod Ffeil Cofnodi
+about-networking-set-log-modules = Gosod Modiwlau Cofnodi
+about-networking-start-logging = Cychwyn Cofnodi
+about-networking-stop-logging = Peidio Cofnodi
+about-networking-dns-lookup = Chwilio DNS
+about-networking-dns-lookup-button = Datrys
+about-networking-dns-domain = Parth:
+about-networking-dns-lookup-table-column = IPau
+about-networking-dns-https-rr-lookup-table-column = HTTP RRs
+about-networking-rcwn = Statws RCWN
+about-networking-rcwn-status = Statws RCWN
+about-networking-rcwn-cache-won-count = Cyfrif storfa dros dro wedi ei ennill
+about-networking-rcwn-net-won-count = Cyfrif rhwyd wedi ei ennill
+about-networking-total-network-requests = Cyfanswm cyfrif ceisiadau rhwydwaith
+about-networking-rcwn-operation = Gweithred Storfa Dros Dro
+about-networking-rcwn-perf-open = Ar Agor
+about-networking-rcwn-perf-read = Darllen
+about-networking-rcwn-perf-write = Ysgrifennu
+about-networking-rcwn-perf-entry-open = Cofnod Ar Agor
+about-networking-rcwn-avg-short = Cyfartaledd Hir
+about-networking-rcwn-avg-long = Cyfartaledd Hir
+about-networking-rcwn-std-dev-long = Gwyriad Safonol Hir
+about-networking-rcwn-cache-slow = Cyfrif araf storfa dros dro
+about-networking-rcwn-cache-not-slow = Cyfrif nid araf storfa dros dro
+about-networking-networkid = ID Rhwydwaith
+about-networking-networkid-id = ID Rhwydwaith
+
+## Link is intended as "network link"
+
+about-networking-networkid-is-up = Mae'r cyswllt ar i fyny
+about-networking-networkid-status-known = Mae statws y cyswllt yn hysbys
+
+##
+
diff --git a/l10n-cy/toolkit/toolkit/about/aboutPerformance.ftl b/l10n-cy/toolkit/toolkit/about/aboutPerformance.ftl
new file mode 100644
index 0000000000..cf5b3270e2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutPerformance.ftl
@@ -0,0 +1,67 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Page title
+about-performance-title = Rheolwr Tasgau
+
+## Column headers
+
+column-name = Enw
+column-type = Math
+column-energy-impact = Effaith Ynni
+column-memory = Cof
+
+## Special values for the Name column
+
+ghost-windows = Tabiau Wedi'u Cau'n Ddiweddar
+# Variables:
+#   $title (String) - the title of the preloaded page, typically 'New Tab'
+preloaded-tab = Rhaglwytho: { $title }
+
+## Values for the Type column
+
+type-tab = Tab
+type-subframe = Is-ffrâm
+type-tracker = Traciwr
+type-addon = Ychwanegyn
+type-browser = Porwr
+type-worker = Gweithiwr
+type-other = Arall
+
+## Values for the Energy Impact column
+##
+## Variables:
+##   $value (Number) - Value of the energy impact, eg. 0.25 (low),
+##                     5.38 (medium), 105.38 (high)
+
+energy-impact-high = Uchel ({ $value })
+energy-impact-medium = Canolig ({ $value })
+energy-impact-low = Isel ({ $value })
+
+## Values for the Memory column
+##
+## Variables:
+##   $value (Number) - How much memory is used
+
+size-KB = { $value } KB
+size-MB = { $value } MB
+size-GB = { $value } GB
+
+## Tooltips for the action buttons
+
+close-tab =
+    .title = Cau tab
+show-addon =
+    .title = Dangos yn y Rheolwr Ychwanegion
+
+# Tooltip when hovering an item of the about:performance table
+# Variables:
+#   $totalDispatches (Number) - how many dispatches occured for this page since it loaded
+#   $totalDuration (Number) - how much CPU time was used by this page since it loaded
+#   $dispatchesSincePrevious (Number) - how many dispatches occured in the last 2 seconds
+#   $durationSincePrevious (Number) - how much CPU time was used in the last 2 seconds
+item =
+    .title =
+        Negeseuon ers llwytho: { $totalDispatches } ({ $totalDuration } ms)
+        Negeseuon yn yr eiliadau diwethaf: { $dispatchesSincePrevious } ({ $durationSincePrevious } ms)
diff --git a/l10n-cy/toolkit/toolkit/about/aboutPlugins.ftl b/l10n-cy/toolkit/toolkit/about/aboutPlugins.ftl
new file mode 100644
index 0000000000..3f0e67144f
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutPlugins.ftl
@@ -0,0 +1,35 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+title-label = Ynghylch Ategion
+
+installed-plugins-label = Ategion wedi eu gosod
+no-plugins-are-installed-label = Heb ganfod ategion wedi eu gosod
+
+deprecation-description = Colli rhywbeth? Nid yw rhai ategion yn cael eu cynnal. <a data-l10n-name="deprecation-link">Dysgu Rhagor.</a>
+
+## The information of plugins
+##
+## Variables:
+##   $pluginLibraries: the plugin library
+##   $pluginFullPath: path of the plugin
+##   $version: version of the plugin
+
+file-dd = <span data-l10n-name="file">Ffeil:</span> { $pluginLibraries }
+path-dd = <span data-l10n-name="path">Llwybr:</span> { $pluginFullPath }
+version-dd = <span data-l10n-name="version">Fersiwn:</span> { $version }
+
+## These strings describe the state of plugins
+##
+## Variables:
+##   $blockListState: show some special state of the plugin, such as blocked, outdated
+
+state-dd-enabled = <span data-l10n-name="state">Sir/Talaith:</span> Galluogwyd
+state-dd-enabled-block-list-state = <span data-l10n-name="state">Sir/Talaith:</span> Galluogwyd ({ $blockListState })
+state-dd-Disabled = <span data-l10n-name="state">Sir/Talaith:</span> Analluogwyd
+state-dd-Disabled-block-list-state = <span data-l10n-name="state">Sir/Talaith:</span> Analluogwyd ({ $blockListState })
+
+mime-type-label = Math MIME
+description-label = Disgrifiad
+suffixes-label = Rhagosodiad
diff --git a/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl b/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl
new file mode 100644
index 0000000000..6bb170b113
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl
@@ -0,0 +1,133 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Page title
+about-processes-title = Rheolwr Prosesau
+# The Actions column
+about-processes-column-action =
+    .title = Gweithredoedd
+
+## Tooltips
+
+about-processes-shutdown-process =
+    .title = Dadlwytho tabiau a lladd y broses
+about-processes-shutdown-tab =
+    .title = Cau tab
+
+## Column headers
+
+about-processes-column-name = Enw
+about-processes-column-memory-resident = Cof
+about-processes-column-cpu-total = CPU
+
+## Process names
+## Variables:
+##    $pid (String) The process id of this process, assigned by the OS.
+##    $origin (String) The domain name for this process.
+##    $type (String) The raw type for this process. Used for unknown processes.
+
+about-processes-browser-process-name = (proses { $pid }) { -brand-short-name }
+about-processes-web-process-name = Gwe (proses { $pid }, wedi'i rannu)
+about-processes-web-isolated-process-name = Gwe (proses { $pid }) ar gyfer { $origin }
+about-processes-web-large-allocation = Gwe (proses { $pid }, mawr) ar gyfer { $origin }
+about-processes-with-coop-coep-process-name = Gwe (proses { $pid }, traws-darddiad ynyswyd) ar gyfer { $origin }
+about-processes-file-process-name = Ffeiliau (proses { $pid })
+about-processes-extension-process-name = Estyniadau (proses { $pid })
+about-processes-privilegedabout-process-name = Ynghylch (proses { $pid })
+about-processes-plugin-process-name = Ategion (proses { $pid })
+about-processes-privilegedmozilla-process-name = Gwe (proses { $pid }) ar gyfer gwefannau { -vendor-short-name }
+about-processes-gmp-plugin-process-name = Ategion Cyfryngau Gecko (proses { $pid })
+about-processes-gpu-process-name = GPU (proses { $pid })
+about-processes-vr-process-name = VR (proses { $pid })
+about-processes-rdd-process-name = Datgodiwr Data (proses { $pid })
+about-processes-socket-process-name = Rhwydwaith (proses { $pid })
+about-processes-remote-sandbox-broker-process-name = Brocer Blwch Tywod Pell (proses { $pid })
+about-processes-fork-server-process-name = Gweinydd Fforc (proses { $pid })
+about-processes-preallocated-process-name = Rhag-ddyrannwyd (proses { $pid })
+about-processes-unknown-process-name = Arall ({ $type }, proses { $pid })
+# Process
+# Variables:
+#   $name (String) The name assigned to the process.
+#   $pid (String) The process id of this process, assigned by the OS.
+about-processes-process-name = Proses { $pid }: { $name }
+
+## Details within processes
+
+# Single-line summary of threads
+# Variables:
+#    $number (Number) The number of threads in the process. Typically larger
+#                     than 30. We don't expect to ever have processes with less
+#                     than 5 threads.
+about-processes-thread-summary = Trywyddau ({ $number })
+# Thread details
+# Variables:
+#   $name (String) The name assigned to the thread.
+#   $tid (String) The thread id of this thread, assigned by the OS.
+about-processes-thread-name = Trywydd { $tid }: { $name }
+# Tab
+# Variables:
+#   $name (String) The name of the tab (typically the title of the page, might be the url while the page is loading).
+about-processes-tab-name = Tab: { $name }
+about-processes-preloaded-tab = Tab Newydd wedi'i Rhag-lwytho
+# Single subframe
+# Variables:
+#   $url (String) The full url of this subframe.
+about-processes-frame-name-one = Is-ffrâm: { $url }
+# Group of subframes
+# Variables:
+#   $number (Number) The number of subframes in this group. Always ≥ 1.
+#   $shortUrl (String) The shared prefix for the subframes in the group.
+about-processes-frame-name-many = Is-fframiau ({ $number }): { $shortUrl }
+
+## Displaying CPU (percentage and total)
+## Variables:
+##    $percent (Number) The percentage of CPU used by the process or thread.
+##                      Always > 0, generally <= 200.
+##    $total (Number) The amount of time used by the process or thread since
+##                    its start.
+##    $unit (String) The unit in which to display $total. See the definitions
+##                   of `duration-unit-*`.
+
+# Common case.
+about-processes-cpu-user-and-kernel = { NUMBER($percent, maximumSignificantDigits: 2, style: "percent") } ({ NUMBER($total, maximumFractionDigits: 0) }{ $unit })
+# Special case: data is not available yet.
+about-processes-cpu-user-and-kernel-not-ready = (yn mesur)
+# Special case: process or thread is currently idle.
+about-processes-cpu-user-and-kernel-idle = segur ({ NUMBER($total, maximumFractionDigits: 2) }{ $unit })
+
+## Displaying Memory (total and delta)
+## Variables:
+##    $total (Number) The amount of memory currently used by the process.
+##    $totalUnit (String) The unit in which to display $total. See the definitions
+##                        of `memory-unit-*`.
+##    $delta (Number) The absolute value of the amount of memory added recently.
+##    $deltaSign (String) Either "+" if the amount of memory has increased
+##                        or "-" if it has decreased.
+##    $deltaUnit (String) The unit in which to display $delta. See the definitions
+##                        of `memory-unit-*`.
+
+# Common case.
+about-processes-total-memory-size = { NUMBER($total, maximumFractionDigits: 0) }{ $totalUnit } ({ $deltaSign }{ NUMBER($delta, maximumFractionDigits: 0) }{ $deltaUnit })
+# Special case: no change.
+about-processes-total-memory-size-no-change = { NUMBER($total, maximumFractionDigits: 0) }{ $totalUnit }
+
+## Duration units
+
+duration-unit-ns = ns
+duration-unit-us = µs
+duration-unit-ms = ms
+duration-unit-s = e
+duration-unit-m = m
+duration-unit-h = a
+duration-unit-d = d
+
+## Memory units
+
+memory-unit-B = B
+memory-unit-KB = KB
+memory-unit-MB = MB
+memory-unit-GB = GB
+memory-unit-TB = TB
+memory-unit-PB = PB
+memory-unit-EB = EB
diff --git a/l10n-cy/toolkit/toolkit/about/aboutProfiles.ftl b/l10n-cy/toolkit/toolkit/about/aboutProfiles.ftl
new file mode 100644
index 0000000000..6f53902fcf
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutProfiles.ftl
@@ -0,0 +1,74 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+profiles-title = Ynghylch Proffiliau
+profiles-subtitle = Mae'r dudalen hon yn eich helpu i reoli eich proffiliau. Mae pob proffil yn fyd ar wahân sy'n cynnwys hanes, nodau tudalen, gosodiadau ac yn ychwanegion gwahanol.
+profiles-create = Creu Proffil Newydd
+profiles-restart-title = Ailgychwyn
+profiles-restart-in-safe-mode = Ailgychwyn gydag Ychwanegion wedi eu Hanablu…
+profiles-restart-normal = Ailgychwyn fel arfer…
+profiles-conflict = Mae copi arall o { -brand-product-name } wedi gwneud newidiadau i broffiliau. Rhaid ailgychwyn { -brand-short-name } cyn gwneud mwy o newidiadau.
+profiles-flush-fail-title = Heb gadw'r newidiadau
+profiles-flush-conflict = { profiles-conflict }
+profiles-flush-failed = Mae gwall annisgwyl wedi atal eich newidiadau rhag cael eu cadw.
+profiles-flush-restart-button = Ailgychwyn { -brand-short-name }
+
+# Variables:
+#   $name (String) - Name of the profile
+profiles-name = Proffil: { $name }
+profiles-is-default = Proffil Ragosodedig
+profiles-rootdir = Cyfarwyddiadur Gwraidd
+
+# localDir is used to show the directory corresponding to
+# the main profile directory that exists for the purpose of storing data on the
+# local filesystem, including cache files or other data files that may not
+# represent critical user data. (e.g., this directory may not be included as
+# part of a backup scheme.)
+# In case localDir and rootDir are equal, localDir is not shown.
+profiles-localdir = Cyfarwyddiadur Lleol
+profiles-current-profile = Dyma'r proffil sy'n cael ei ddefnyddio ac nid oes modd ei ddileu.
+profiles-in-use-profile = Mae'r proffil yn cael ei ddefnyddio o fewn rhaglen arall ac nid oes modd ei ddileu.
+
+profiles-rename = Ailenwi
+profiles-remove = Tynnu
+profiles-set-as-default = Gosod fel y proffil ragosodedig
+profiles-launch-profile = Cychwyn proffil yn y porwr newydd
+
+profiles-cannot-set-as-default-title = Methu gosod y rhagosodedig
+profiles-cannot-set-as-default-message = Nid oes modd newid y proffil rhagosodedig am { -brand-short-name }.
+
+profiles-yes = iawn
+profiles-no = na
+
+profiles-rename-profile-title = Newid Enw Proffil
+# Variables:
+#   $name (String) - Name of the profile
+profiles-rename-profile = Ailenwi proffil { $name }
+
+profiles-invalid-profile-name-title = Enw proffil annilys
+# Variables:
+#   $name (String) - Name of the profile
+profiles-invalid-profile-name = Methu caniatáu enw proffil "{ $name }".
+
+profiles-delete-profile-title = Dileu Proffil
+# Variables:
+#   $dir (String) - Path to be displayed
+profiles-delete-profile-confirm =
+    Bydd dileu proffil yn tynnu'r proffil o'r rhestr o broffiliau sydd ar gael ac nid oes modd ei ddadwneud.
+    Gallwch hefyd ddewis i ddileu ffeiliau data proffil, gan gynnwys eich gosodiadau, tystysgrifau a data arall yn perthyn i ddefnyddwyr. Bydd y dewis hwn yn dileu ffolder "{ $dir }" ac nid oes modd ei ddadwneud.
+    Hoffech chi ddileu'r ffeiliau data proffil?
+profiles-delete-files = Dileu Ffeiliau
+profiles-dont-delete-files = Peidio Dileu Ffeiliau
+
+profiles-delete-profile-failed-title = Gwall
+profiles-delete-profile-failed-message = Bu gwall wrth geisio dileu'r proffil hwn.
+
+
+profiles-opendir =
+    { PLATFORM() ->
+        [macos] Dangos yn Finder
+        [windows] Agor Ffolder
+       *[other] Agor Cyfeiriadur
+    }
diff --git a/l10n-cy/toolkit/toolkit/about/aboutRights.ftl b/l10n-cy/toolkit/toolkit/about/aboutRights.ftl
new file mode 100644
index 0000000000..541a34c7f7
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutRights.ftl
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+rights-title = Ynghylch eich hawliau
+rights-intro = Mae { -brand-full-name } yn feddalwedd cod agored rhydd a rhad, wedi ei adeiladu gan gymuned o filoedd o bobl ar draws y byd i gyd. Mae yna rhai pethau i chi gael gwybod:
+rights-intro-point-1 = Mae { -brand-short-name } ar gael i chi o dan amodau'r <a data-l10n-name="mozilla-public-license-link">Trwydded Gyhoeddus Mozilla</a>. Mae hyn yn golygu y cewch ddefnyddio, gopïo a dosbarthu { -brand-short-name } i eraill.  Mae croeso i chi newid cod ffynhonnell { -brand-short-name } yn ôl eich angen. Mae Trwydded Gyhoeddus Mozilla yn rhoi'r hawl i chi ddosbarthu'r fersiwn rydych wedi ei newid.
+rights-intro-point-2 = Nid ydych yn derbyn unrhyw hawliau nod masnachu na thrwyddedau i nod masnach y Mozilla Foundation neu unrhyw barti, gan gynnwys y Mozzilla Foundation heb gyfyngiadau i enw na logo Firefox. Mae gwybodaeth bellach am nodau masnach i’w cael <a data-l10n-name="mozilla-trademarks-link">yma</a>.
+rights-intro-point-3 = Mae rhai nodweddion yn { -brand-short-name }, megis yr Adroddwr Chwalu, yn rhoi'r dewis i chi gyfrannu adborth i { -vendor-short-name }. Drwy ddewis cyflwyno adborth rydych yn rhoi i { -vendor-short-name } ganiatâd i ddefnyddio'r adborth i wella ei gynnyrch, i gyhoeddi'r adborth ar ei wefannau, ac i ddosbarthu'r adborth.
+rights-intro-point-4 = Mae sut rydym yn defnyddio y data personol ac adborth rydych wedi ei gyflwyno i { -vendor-short-name } drwy { -brand-short-name } yn cael ei ddisgrifio yn <a data-l10n-name="mozilla-privacy-policy-link">Polisi Preifatrwydd { -brand-short-name }</a>.
+rights-intro-point-4-unbranded = Rhaid rhestri unrhyw bolisïau preifatrwydd perthnasol yma.
+rights-intro-point-5 = Mae rhai nodweddion { -brand-short-name } yn gwneud defnydd p wasanaethau gwybodaeth gwe, er hynny nid ydym yn gallu gwarantu eu bod yn 100% yn gywir nac yn rhydd o wallau. Mae rhagor o fanylion, gan gynnwys gwybodaeth ar sut i'w hanalluogi i'w cael yn yr <a data-l10n-name="mozilla-service-terms-link">amodau gwasanaeth</a>.
+rights-intro-point-5-unbranded = Os yw'r cynnyrch yn cynnwys gwasanaethau gwe, rhaid cysylltu unrhyw amodau gwasanaeth perthnasol ar gyfer y gwasanaeth(au) i'r adran <a data-l10n-name="mozilla-website-services-link">Gwasanaethau Gwefan</a> Gwe.
+rights-intro-point-6 = Er mwyn chwarae rhai mathau o gynnwys fideo, mae { -brand-short-name } yn llwytho i lawr rhywfaint o gynnwys modiwlau dadgryptio gan drydydd partïon.
+rights-webservices-header = Gwasanaethau Gwybodaeth Gwe { -brand-full-name }
+rights-webservices = Mae { -brand-full-name } yn defnyddio gwasanaethau gwybodaeth gwe ("Gwasanaethau") i ddarparu rhai o'r nodweddion sy'n cael eu darparu ar eich cyfer yn y fersiwn yma o { -brand-short-name } o fewn yr amodau disgrifir isod. Os nad ydych am ddefnyddio un neu fwy o'r Gwasanaethau neu mae'r amodau yn annerbyniol, mae modd i chi analluogi'r nodwedd neu'r Gwasanaeth(au). Mae gwybodaeth ar sut i analluogi nodwedd neu Wasanaeth penodol i'w cael <a data-l10n-name="mozilla-disable-service-link">yma</a>. Mae modd analluogi nodweddion a Gwasanaethau eraill yn newisiadau'r rhaglen.
+rights-safebrowsing = <strong>Pori Diogel: </strong>Nid yw anablu Pori Diogel yn cael ei gymeradwyo gan y gall arwain i chi fynd i wefannau anniogel.  Os ydych eisiau analluogi'r nodwedd yn llwyr, dilynwch y camau hyn:
+rights-safebrowsing-term-1 = Agor dewisiadau'r rhaglen
+rights-safebrowsing-term-2 = Dewis Diogelwch
+rights-safebrowsing-term-3 = Dad dicio'r dewis i "{ enableSafeBrowsing-label }"
+enableSafeBrowsing-label = Rhwystro cynnwys peryglus a thwyllodrus
+rights-safebrowsing-term-4 = Mae Pori Diogel wedi ei analluogi
+rights-locationawarebrowsing = <strong>Pori Ymwybodol o Leoliad: </strong>yn ddewis i chi bob tro.  Ni fydd gwybodaeth yn cael ei anfon heb eich caniatâd.  Os hoffech chi analluogi'r nodwedd yn llwyr, dilynwch y camau hyn:
+rights-locationawarebrowsing-term-1 = Yn y bar URL, teipiwch <code>about:config</code>
+rights-locationawarebrowsing-term-2 = Teipio geo.enabled
+rights-locationawarebrowsing-term-3 = Clic dwbl i'r dewis geo.enabled
+rights-locationawarebrowsing-term-4 = Mae Pori Ymwybodol o Leoliad wedi ei analluogi
+rights-webservices-unbranded = Rhaid cynnwys yn fan hyn, drosolwg o'r gwasanaeth gwefan gwe mae'r cynnyrch yn ei gynnwys, ynghyd â chyfarwyddiadau ar sut i'w hatal os yn berthnasol.
+rights-webservices-term-unbranded = Rhaid rhestru amodau gwasanaethau gwe yma.
+rights-webservices-term-1 = Mae { -vendor-short-name } a'i gyfranwyr, trwyddedwyr, a phartneriaid yn gweithio i ddarparu'r Gwasanaethau mwyaf cywir a chyfredol.  Er hynny, nid oes modd i ni warantu fod y wybodaeth yn gynhwysfawr a diwall.  Er enghraifft, efallai na fydd y Gwasanaeth Pori Diogel yn adnabod rhai gwefannau anniogel ac efallai adnabod rhai gwefannau diogel ar gam. Mae pob lleoliad sy'n cael ei ddychwelyd gan ein darparwyr gwasanaeth ar gyfer y Gwasanaeth Ymwybodol o Leoliad yn amcanion yn unig. Nid ydym ni na'r darparwyr gwasanaeth yn gallu gwarantu cywirdeb y lleoliadau hyn.
+rights-webservices-term-2 = Gall { -vendor-short-name } atal neu newid y Gwasanaethau yn ôl eu mympwy.
+rights-webservices-term-3 = Mae croeso i chi ddefnyddio'r Gwasanaethau hyn gyda'r fersiwn yma o { -brand-short-name }, ac mae { -vendor-short-name } rhoi ei hawl i chi wneud hynny.  Mae { -vendor-short-name } a'i drwyddedwyr yn diogelu pob hawl arall yn y Gwasanaethau.  Nid yw'r amodau wedi eu hanelu at gyfyngu unrhyw hawliau o dan drwyddedau cod agored sy'n perthyn i { -brand-short-name } ac i'r fersiynau perthnasol o ffynonellau cod { -brand-short-name }.
+rights-webservices-term-4 = <strong>Mae'r gwasanaeth yn cael ei ddarparu "fel ag y mae".  Mae { -vendor-short-name }, ei gyfranwyr, trwyddedwyr, a dosbarthwyr, yn gwadu unrhyw warant, p'un ai yn cael ei fynegi neu ei awgrymu, gan gynnwys heb gyfyngiad, gwarant fod y Gwasanaethau yn farchnadadwy nac yn addas i'ch pwrpas penodol.  Rydych yn derbyn yr holl risg o ddewis y Gwasanaethau ar gyfer eich pwrpas ac i natur ansawdd a pherfformiad y Gwasanaeth. Nid yw rhai awdurdodau'n caniatáu eithrio neu gyfyngu gwarant sy'n cael ei awgrymu felly efallai nad yw'r gwadiad hwn yn berthnasol i chi.</strong>
+rights-webservices-term-5 = <strong>Yn wahanol i'r hyn sy'n angenrheidiol yn ôl y gyfraith, ni fydd { -vendor-short-name }, ei gyfranwyr, trwyddedwyr a dosbarthwyr yn agored i unrhyw iawndal anuniongyrchol, arbenigol, achlysurol, neu enghreifftiol yn codi o neu mewn unrhyw ffordd yn berthnasol i'r defnydd o { -brand-short-name } a'r Gwasanaethau.   Ni fydd yr atebolrwydd cyfunol o dan yr amodau hyn yn fwy na $500 (pum can dollar). Nid yw rhai awdurdodau yn caniatáu cyfyngu ar rhai materion difrod, felly efallai na fydd hyn yn berthnasol i chi.</strong>
+rights-webservices-term-6 = Gall { -vendor-short-name } ddiweddaru'r amodau yn ôl y galw o bryd i'w gilydd. Nid oes modd newid na dileu'r amodau heb ganiatâd ysgrifenedig { -vendor-short-name }.
+rights-webservices-term-7 = Mae'r amodau yn cael eu rheoli gan gyfreithiau talaith California, UDA, gan hepgor ei ddarpariaethau gwrthdaro cyfreithiol. Os yw unrhyw ran o'r amodau i'w cael heb rym cyfreithiol byd y gweddill yn sefyll mewn grym llawn ac effaith. Os digwydd gwrthdaro rhwng fersiwn sydd wedi ei gyfieithu a'r amodau hyn a'r fersiwn Saesneg, y fersiwn Saesneg fydd yn rheoli.
diff --git a/l10n-cy/toolkit/toolkit/about/aboutServiceWorkers.ftl b/l10n-cy/toolkit/toolkit/about/aboutServiceWorkers.ftl
new file mode 100644
index 0000000000..9474662afb
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutServiceWorkers.ftl
@@ -0,0 +1,40 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### The term "Service Workers" and "Workers" should not be translated
+
+about-service-workers-title = Ynghylch Service Workers
+about-service-workers-main-title = Service Workers Cofrestredig
+about-service-workers-warning-not-enabled = Nid yw Service Workers wedi eu galluogi.
+about-service-workers-warning-no-service-workers = Does dim Service Workers wedi eu cofrestru.
+
+# The original title of service workers' information
+#
+# Variables:
+#   $originTitle: original title
+origin-title = Tarddiad: { $originTitle }
+
+## These strings are for showing the information of workers.
+##
+## Variables:
+##  $name: the name of scope, active cache, waiting cache and the push end point.
+##  $url: the url of script specification and current worker.
+
+scope = <strong>Ystod:</strong> { $name }
+script-spec = <strong>Manyleb Sgript:</strong> <a data-l10n-name="link">{ $url }</a>
+current-worker-url = <strong>URL Worker Cyfredol:</strong> <a data-l10n-name="link">{ $url }</a>
+active-cache-name = <strong>Enw'r Storfa Dros Dro Weithredol:</strong> { $name }
+waiting-cache-name = <strong>Enw'r Storfa Dros Dro sy'n Aros:</strong> { $name }
+push-end-point-waiting = <strong>Push Endpoint:</strong> { waiting }
+push-end-point-result = <strong>Push Endpoint:</strong> { $name }
+
+# This term is used as a button label (verb, not noun).
+update-button = Diweddaru
+
+unregister-button = Dadgofrestru
+
+unregister-error = Methwyd dadgofrestru'r Service Workers.
+
+waiting = Aros…
diff --git a/l10n-cy/toolkit/toolkit/about/aboutSupport.ftl b/l10n-cy/toolkit/toolkit/about/aboutSupport.ftl
new file mode 100644
index 0000000000..330dab3812
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutSupport.ftl
@@ -0,0 +1,425 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+page-title = Gwybodaeth am Ddatrys Problemau
+page-subtitle = Mae'r dudalen hon yn cynnwys gwybodaeth dechnegol a allai fod yn ddefnyddiol pan fyddwch yn ceisio datrys problem. Os ydych yn chwilio am atebion i gwestiynau cyffredin am { -brand-short-name }, edrychwch ar ein <a data-l10n-name="support-link">gwefan cefnogaeth</a>.
+crashes-title = Ardroddiad Chwalu
+crashes-id = Enw'r Adroddiad
+crashes-send-date = Cyflwynwyd
+crashes-all-reports = Pob Adroddiad Chwalu
+crashes-no-config = Mae'r rhaglen wedi ei ffurfweddu i ddangos adroddiadau chwalu.
+extensions-title = Estyniadau
+extensions-name = Enw
+extensions-enabled = Galluogwyd
+extensions-version = Fersiwn
+extensions-id = ID
+support-addons-title = Ychwanegion
+support-addons-name = Enw
+support-addons-type = Math
+support-addons-enabled = Galluogwyd
+support-addons-version = Fersiwn
+support-addons-id = ID
+security-software-title = Meddalwedd Diogelwch
+security-software-type = Math
+security-software-name = Enw
+security-software-antivirus = Gwrth Firws
+security-software-antispyware = Gwrthysbiwar
+security-software-firewall = Mur Cadarn
+features-title = Nodweddion { -brand-short-name }
+features-name = Enw
+features-version = Fersiwn
+features-id = ID
+processes-title = Prosesau Pell
+processes-type = Math
+processes-count = Cyfrif
+app-basics-title = Sylfaeni Rhaglen
+app-basics-name = Enw
+app-basics-version = Fersiwn
+app-basics-build-id = Cyfeirnod Adeiladu
+app-basics-distribution-id = ID Dosbarthu
+app-basics-update-channel = Sianel Diweddaru
+# This message refers to the folder used to store updates on the device,
+# as in "Folder for updates". "Update" is a noun, not a verb.
+app-basics-update-dir =
+    { PLATFORM() ->
+        [linux] Diweddaru Cyfeiriadur
+       *[other] Diweddaru Ffolder
+    }
+app-basics-update-history = Hanes Diweddaru
+app-basics-show-update-history = Dangos Hanes Diweddaru
+# Represents the path to the binary used to start the application.
+app-basics-binary = Deuaidd y Rhaglen
+app-basics-profile-dir =
+    { PLATFORM() ->
+        [linux] Cyfeiriadur Proffil
+       *[other] Ffolder Proffil
+    }
+app-basics-enabled-plugins = Ategion Galluogwyd
+app-basics-build-config = Ffurfweddiad Adeiladu
+app-basics-user-agent = Asiant Defnyddiwr
+app-basics-os = SW
+# Rosetta is Apple's translation process to run apps containing x86_64
+# instructions on Apple Silicon. This should remain in English.
+app-basics-rosetta = Cyfieithu gan Rosetta
+app-basics-memory-use = Defnydd o'r cof
+app-basics-performance = Perfformiad
+app-basics-service-workers = Service Workers Cofrestredig
+app-basics-profiles = Proffiliau
+app-basics-launcher-process-status = Proses Lansio
+app-basics-multi-process-support = Ffenestri Amlbroses
+app-basics-fission-support = Ffenestri Fission
+app-basics-remote-processes-count = Prosesau Pell
+app-basics-enterprise-policies = Polisïau Mentrau
+app-basics-location-service-key-google = Allwedd Google Location Service
+app-basics-safebrowsing-key-google = Allwedd Google Safebrowsing
+app-basics-key-mozilla = Mozilla Location Service Key
+app-basics-safe-mode = Modd Diogel
+show-dir-label =
+    { PLATFORM() ->
+        [macos] Dangos yn Finder
+        [windows] Agor Ffolder
+       *[other] Agor Cyfeiriadur
+    }
+environment-variables-title = Newidiolion Amgylcheddol
+environment-variables-name = Enw
+environment-variables-value = Gwerth
+experimental-features-title = Nodweddion Arbrofol
+experimental-features-name = Enw
+experimental-features-value = Gwerth
+modified-key-prefs-title = Dewisiadau Pwysig wedi eu Newid
+modified-prefs-name = Enw
+modified-prefs-value = Gwerth
+user-js-title = Dewisiadau user.js
+user-js-description = Mae eich ffolder profil yn cynnwys <a data-l10n-name="user-js-link">ffeil user.js</a>, sy'n cynnwys dewisiadau sydd heb eu creu gan { -brand-short-name }.
+locked-key-prefs-title = Dewisiadau Pwysig Wedi eu Cloi
+locked-prefs-name = Enw
+locked-prefs-value = Gwerth
+graphics-title = Graffigau
+graphics-features-title = Nodweddion
+graphics-diagnostics-title = Diagnosteg
+graphics-failure-log-title = Cofnod Methiant
+graphics-gpu1-title = GPU #1
+graphics-gpu2-title = GPU #2
+graphics-decision-log-title = Cofnod Penderfynnu
+graphics-crash-guards-title = Nodweddion Crash Guard wedi ei Analluogi
+graphics-workarounds-title = Dulliau Datrys
+# Windowing system in use on Linux (e.g. X11, Wayland).
+graphics-window-protocol = Protocol Ffenestr
+# Desktop environment in use on Linux (e.g. GNOME, KDE, XFCE, etc).
+graphics-desktop-environment = Amgylchedd Bwrdd Gwaith
+place-database-title = Cronfa Ddata Mannau
+place-database-integrity = Cyfanrwydd
+place-database-verify-integrity = Gwirio Cyfanrwydd
+a11y-title = Hygyrchedd
+a11y-activated = Gweithredu
+a11y-force-disabled = Atal Hygyrchedd
+a11y-handler-used = Defnyddiwyd Trinydd Mynediadwy
+a11y-instantiator = Enghreifftiad Hygyrchedd
+library-version-title = Fersiynau Llyfrgell
+copy-text-to-clipboard-label = Copïo testun i'r clipfwrdd
+copy-raw-data-to-clipboard-label = Copïo data bras i'r clipfwrdd
+sandbox-title = Blwch tywod
+sandbox-sys-call-log-title = Galwadau System wedi eu Gwrthod
+sandbox-sys-call-index = #
+sandbox-sys-call-age = Eiliad yn Ôl
+sandbox-sys-call-pid = PID
+sandbox-sys-call-tid = TID
+sandbox-sys-call-proc-type = Math o Brosesu
+sandbox-sys-call-number = Syscall
+sandbox-sys-call-args = Ymresymiadau
+safe-mode-title = Defnyddiwch y Modd Diogel
+restart-in-safe-mode-label = Ailgychwyn gydag Ychwanegion wedi eu Hanalluogi…
+clear-startup-cache-title = Ceisiwch glirio'r storfa gychwyn
+clear-startup-cache-label = Clirio'r storfa gychwyn…
+startup-cache-dialog-title = Clirio'r storfa gychwyn
+startup-cache-dialog-body = Ailgychwyn { -brand-short-name } i glirio storfa cychwyn. Ni fydd hyn yn newid eich gosodiadau nac yn dileu estyniadau rydych chi wedi'u hychwanegu at { -brand-short-name }.
+restart-button-label = Ailgychwyn
+
+## Media titles
+
+audio-backend = Cefn Sain
+max-audio-channels = Mwyaf o Sianeli
+sample-rate = Graddfa Samplo Amgen
+roundtrip-latency = Cylchdro cudd (gwyriad safonol)
+media-title = Cyfrwng
+media-output-devices-title = Dyfeisiau Allbwn
+media-input-devices-title = Dyfeisiau Mewnbwn
+media-device-name = Enw
+media-device-group = Grŵp
+media-device-vendor = Gwerthwr
+media-device-state = Cyflwr
+media-device-preferred = Amgen
+media-device-format = Fformat
+media-device-channels = Sianeli
+media-device-rate = Cyfradd
+media-device-latency = Cuddni
+media-capabilities-title = Gallu Cyfryngol
+# List all the entries of the database.
+media-capabilities-enumerate = Cyfrifo'r gronfa ddata
+
+##
+
+intl-title = Rhyngwladoli a Lleoleiddio
+intl-app-title = Gosodiadau'r Rhaglen
+intl-locales-requested = Locales Gofynnwyd Amdanynt
+intl-locales-available = Locales ar Gael
+intl-locales-supported = Locales Apiau
+intl-locales-default = Locale Rhagosodedig
+intl-os-title = System Weithredu
+intl-os-prefs-system-locales = Locales y System
+intl-regional-prefs = Dewisiadau Rhanbarthol
+
+## Remote Debugging
+##
+## The Firefox remote protocol provides low-level debugging interfaces
+## used to inspect state and control execution of documents,
+## browser instrumentation, user interaction simulation,
+## and for subscribing to browser-internal events.
+##
+## See also https://firefox-source-docs.mozilla.org/remote/
+
+remote-debugging-title = Dadfygio o Bell (Protocol Cromiwm)
+remote-debugging-accepting-connections = Derbyn Cysylltiadau
+remote-debugging-url = URL
+
+##
+
+support-third-party-modules-title = Modiwlau Trydydd Parti
+support-third-party-modules-module = Ffeil Modiwlau
+support-third-party-modules-version = Fersiwn Ffeil
+support-third-party-modules-vendor = Manylion y Gwerthwr
+support-third-party-modules-occurrence = Amlder
+support-third-party-modules-process = Math o Broses ac ID
+support-third-party-modules-thread = Trywydd
+support-third-party-modules-base = Cyfeiriad Imagebase
+support-third-party-modules-uptime = Cyfnod Proses (me)
+support-third-party-modules-duration = Cyfnod Llwytho (me)
+support-third-party-modules-status = Statws
+support-third-party-modules-status-loaded = Wedi llwytho
+support-third-party-modules-status-blocked = Wedi Rhwystro
+support-third-party-modules-status-redirected = Wedi Ailgyfeirio
+support-third-party-modules-empty = Heb lwytho unrhyw fodiwlau trydydd parti.
+support-third-party-modules-no-value = (Dim gwerth)
+support-third-party-modules-button-open =
+    .title = Lleoliad ffeil agored...
+support-third-party-modules-expand =
+    .title = Dangos gwybodaeth fanwl
+support-third-party-modules-collapse =
+    .title = Cau gwybodaeth fanwl
+support-third-party-modules-unsigned-icon =
+    .title = Nid yw'r modiwl hwn wedi'i lofnodi
+support-third-party-modules-folder-icon =
+    .title = Lleoliad ffeil agored...
+support-third-party-modules-down-icon =
+    .title = Dangos gwybodaeth fanwl
+support-third-party-modules-up-icon =
+    .title = Cau gwybodaeth fanwl
+# Variables
+# $days (Integer) - Number of days of crashes to log
+report-crash-for-days =
+    { $days ->
+        [zero] Ni fu Adroddiadau Chwalu
+        [one] Adroddiadau Chwalu'r { $days } Diwrnod Diwethaf
+        [two] Adroddiadau Chwalu'r { $days } Ddiwrnod Diwethaf
+        [few] Adroddiadau Chwalu'r { $days } Diwrnod Diwethaf
+        [many] Adroddiadau chwalu'r { $days } Diwrnod Diwethaf
+       *[other] Adroddiadau chwalu'r { $days } Diwrnod Diwethaf
+    }
+# Variables
+# $minutes (integer) - Number of minutes since crash
+crashes-time-minutes =
+    { $minutes ->
+        [zero] Dim munudau yn ôl
+        [one] { $minutes } munud yn ôl
+        [two] { $minutes } funud yn ôl
+        [few] { $minutes } munud yn ôl
+        [many] { $minutes } munud yn ôl
+       *[other] { $minutes } munud yn ôl
+    }
+# Variables
+# $hours (integer) - Number of hours since crash
+crashes-time-hours =
+    { $hours ->
+        [zero] Dim oriau yn ôl
+        [one] { $hours } awr yn ôl
+        [two] { $hours } awr yn ôl
+        [few] { $hours } awr yn ôl
+        [many] { $hours } awr yn ôl
+       *[other] { $hours } awr yn ôl
+    }
+# Variables
+# $days (integer) - Number of days since crash
+crashes-time-days =
+    { $days ->
+        [zero] Dim dyddiau yn ôl
+        [one] { $days } diwrnod yn ôl
+        [two] { $days } ddiwrnod yn ôl
+        [few] { $days } diwrnod yn ôl
+        [many] { $days } diwrnod yn ôl
+       *[other] { $days } diwrnod yn ôl
+    }
+# Variables
+# $reports (integer) - Number of pending reports
+pending-reports =
+    { $reports ->
+        [zero] Dim Adroddiadau Chwalu
+        [one] Pob Adroddiad Chwalu (gan gynnwys { $reports } chwalfa disgwyliedig o fewn ystod penodol o amser)
+        [two] Pob Adroddiad Chwalu (gan gynnwys { $reports } chwalfa disgwyliedig o fewn ystod penodol o amser)
+        [few] Pob Adroddiad Chwalu (gan gynnwys { $reports } chwalfa disgwyliedig o fewn ystod penodol o amser)
+        [many] Pob Adroddiad Chwalu (gan gynnwys { $reports } chwalfa disgwyliedig o fewn ystod penodol o amser)
+       *[other] Pob Adroddiad Chwalu (gan gynnwys { $reports } chwalfa disgwyliedig o fewn ystod penodol o amser)
+    }
+raw-data-copied = Copïwyd data bras i'r clipfwrdd
+text-copied = Copïwyd testun i'r clipfwrdd
+
+## The verb "blocked" here refers to a graphics feature such as "Direct2D" or "OpenGL layers".
+
+blocked-driver = Wedi ei rwystro ar gyfer y fersiwn o'ch gyrrwr graffigol chi.
+blocked-gfx-card = Wedi ei rwystro ar gyfer eich cerdyn graffigol oherwydd pryderon gyrrwr heb eu datrys.
+blocked-os-version = Wedi ei rwystro ar gyfer eich fersiwn chi o'r system weithredu.
+blocked-mismatched-version = Rhwystro ar gyfer gwrthdaro fersiwn gyrrwr graffig y gofrestrfa a'r DLL.
+# Variables
+# $driverVersion - The graphics driver version string
+try-newer-driver = Wedi ei rwystro ar gyfer eich gyrrwr graffigol chi. Ceisiwch ddiweddaru'r gyrrwr i fersiwn { $driverVersion } neu ddiweddarach.
+# "ClearType" is a proper noun and should not be translated. Feel free to leave English strings if
+# there are no good translations, these are only used in about:support
+clear-type-parameters = Paramedrau ClearType
+compositing = Cyfosod
+hardware-h264 = Dadgodio Caledwedd H264
+main-thread-no-omtc = prif drywydd, dim OMTC
+yes = Iawn
+no = Na
+unknown = Anhysbys
+virtual-monitor-disp = Dangosiad Monitor Rhithwir
+
+## The following strings indicate if an API key has been found.
+## In some development versions, it's expected for some API keys that they are
+## not found.
+
+found = Wedi Canfod
+missing = Coll
+gpu-process-pid = GPUProcessPid
+gpu-process = GPUProcess
+gpu-description = Disgrifiad
+gpu-vendor-id = Enw'r Gwerthwr
+gpu-device-id = Enw Dyfais
+gpu-subsys-id = Enw subsys
+gpu-drivers = Gyrwyr
+gpu-ram = RAM
+gpu-driver-vendor = Gwerthwr Gyrwyr
+gpu-driver-version = Fersiwn Gyrrwr
+gpu-driver-date = Dyddiad y Gyrrwr
+gpu-active = Gweithredol
+webgl1-wsiinfo = Gwybodaeth WSI ar yrrwr WebGL 1
+webgl1-renderer = Rendrwr Gyrrwr WebGL 1
+webgl1-version = Fersiwn Gyrrwr WebGL 1
+webgl1-driver-extensions = Estyniadau Gyrrwr WebGL 1
+webgl1-extensions = Estyniadau WebGL 1
+webgl2-wsiinfo = Gwybodaeth WSI Gyrrwr WebGL 2
+webgl2-renderer = Rendrwr Gyrrwr WebGL 2
+webgl2-version = Fersiwn Gyrrwr WebGL 2
+webgl2-driver-extensions = Estyniadau Gyrrwr WebGL 2
+webgl2-extensions = Estyniadau WebGL 2
+blocklisted-bug = Wedi eu rhwystro ar sail gwybodaeth hysbys
+# Variables
+# $bugNumber (string) - String of bug number from Bugzilla
+bug-link = gwall { $bugNumber }
+# Variables
+#   $bugNumber (string) - Bug number on Bugzilla
+support-blocklisted-bug = Ar y Rhestr Rhwystro oherwydd materion hysbys: <a data-l10n-name="bug-link">bug { $bugNumber }</a>
+# Variables
+# $failureCode (string) - String that can be searched in the source tree.
+unknown-failure = Wedi ei rwystro; gwall cod { $failureCode }
+d3d11layers-crash-guard = Cyfosodwr D3D11
+d3d11video-crash-guard = Dadgodiwr Fideo D3D11
+d3d9video-crash-guard = Dadgodiwr Fideo D3D9
+glcontext-crash-guard = OpenGL
+wmfvpxvideo-crash-guard = Dadgodiwr Fideo WMF VPX
+reset-on-next-restart = Ailosod wrth Ailgychwyn
+gpu-process-kill-button = Gorffen Proses GPU
+gpu-device-reset = Ailosod Dyfais
+gpu-device-reset-button = Ailosod Dyfais Trigro
+uses-tiling = Yn defnyddio Teilsio
+content-uses-tiling = Yn Defnyddio Teilsio (Cynnwys)
+off-main-thread-paint-enabled = Galluogwyd Paentio All Brif Drywydd
+off-main-thread-paint-worker-count = Cyfrif Gweithiwr Paentio Oddi ar y Brif Drywydd
+target-frame-rate = Graddfa Ffrâm Darged
+min-lib-versions = Fersiwn lleiaf disgwyliedig
+loaded-lib-versions = Fersiwn mewn defnydd
+has-seccomp-bpf = Seccomp-BPF (Hidlo Galw System)
+has-seccomp-tsync = Cydweddiad Edafedd Seccomp
+has-user-namespaces = Bylchau Enwau Defnyddiwr
+has-privileged-user-namespaces = Bylchau Enw Defnyddiwr fel prosesau breintiedig
+can-sandbox-content = Blwch Tywod Proses Cynnwys
+can-sandbox-media = Blwch Tywod Ategyn Cyfrwng
+content-sandbox-level = Lefel Blwch Tywod Proses Cynnwys
+effective-content-sandbox-level = Lefel Blwch Tywod Proses Cynnwys Effeithiol
+sandbox-proc-type-content = cynnwys
+sandbox-proc-type-file = cynnwys ffeil
+sandbox-proc-type-media-plugin = ategyn cyfrwng
+sandbox-proc-type-data-decoder = datgodydd data
+startup-cache-title = Storfa cychwyn
+startup-cache-disk-cache-path = Llwybr Storfa Disg
+startup-cache-ignore-disk-cache = Anwybyddu Storfa Disg
+startup-cache-found-disk-cache-on-init = Wedi dod o hyd i Storfa Disg ar Init
+startup-cache-wrote-to-disk-cache = Ysgrifennwyd at Storfa Disg
+launcher-process-status-0 = Galluogwyd
+launcher-process-status-1 = Analluogwyd oherwydd methiant
+launcher-process-status-2 = Analluogwyd yn orfodol
+launcher-process-status-unknown = Statws anhysbys
+# Variables
+# $remoteWindows (integer) - Number of remote windows
+# $totalWindows (integer) - Number of total windows
+multi-process-windows = { $remoteWindows }/{ $totalWindows }
+multi-process-status-0 = Galluogwyd gan y defnyddiwr
+multi-process-status-1 = Galluogwyd drwy ragosodiad
+multi-process-status-2 = Analluogwyd
+multi-process-status-4 = Analluogwyd gan offer hygyrchedd
+multi-process-status-6 = Analluogwyd gan fewnbwn testun heb ei gynnal
+multi-process-status-7 = Analluogwyd gan ychwanegion
+multi-process-status-8 = Analluogi gorfodol
+multi-process-status-unknown = Statws anhysbys
+# Variables
+# $fissionWindows (integer) - Number of remote windows
+# $totalWindows (integer) - Number of total windows
+fission-windows = { $fissionWindows }/{ $totalWindows }
+fission-status-experiment-control = Analluogwyd trwy arbrawf
+fission-status-experiment-treatment = Galluogwyd trwy arbrawf
+fission-status-disabled-by-e10s-env = Analluogwyd gan yr amgylchedd
+fission-status-enabled-by-env = Galluogwyd gan yr amgylchedd
+fission-status-disabled-by-safe-mode = Analluogwyd gan y modd diogel
+fission-status-enabled-by-default = Galluogwyd drwy ragosodiad
+fission-status-disabled-by-default = Analluogwyd drwy ragosodiad
+fission-status-enabled-by-user-pref = Galluogwyd gan y defnyddiwr
+fission-status-disabled-by-user-pref = Analluogwyd gan y defnyddiwr
+fission-status-disabled-by-e10s-other = E10s wedi ei analluogi
+async-pan-zoom = Chwyddo a Thremio Anghydamseredig
+apz-none = dim
+wheel-enabled = mewnbwn olwyn wedi ei alluogi
+touch-enabled = mewnbwn cyffwrdd wedi ei alluogi
+drag-enabled = wedi galluogu llusgo bar sgrolio
+keyboard-enabled = bysellfwrdd wedi ei anlluogi
+autoscroll-enabled = galluogwyd awtosgrolio
+zooming-enabled = pinsio chwyddo llyfn wedi'i alluogi
+
+## Variables
+## $preferenceKey (string) - String ID of preference
+
+wheel-warning = Mae mewnbwn olwyn async wedi ei analluogi oherwydd diffyg cefnogaeth pref: { $preferenceKey }
+touch-warning = Mae mewnbwn cyffwrdd async wedi ei analluogi oherwydd diffyg cefnogaeth pref: { $preferenceKey }
+
+## Strings representing the status of the Enterprise Policies engine.
+
+policies-inactive = Anweithredol
+policies-active = Gweithredol
+policies-error = Gwall
+
+## Printing section
+
+support-printing-title = Yn argraffu
+support-printing-troubleshoot = Datrys Anawsterau
+support-printing-clear-settings-button = Clirio gosodiadau argraffu wedi'u cadw
+support-printing-modified-settings = Gosodiadau argraffu wedi'u haddasu
+support-printing-prefs-name = Enw
+support-printing-prefs-value = Gwerth
diff --git a/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl b/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl
new file mode 100644
index 0000000000..4766c6b2af
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl
@@ -0,0 +1,151 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+about-telemetry-ping-data-source = Ffynhonnell data ping:
+about-telemetry-show-current-data = Data cyfredol
+about-telemetry-show-archived-ping-data = Data ping wedi ei archifo
+about-telemetry-show-subsession-data = Dangos data is-sesiwn
+about-telemetry-choose-ping = Dewis ping:
+about-telemetry-archive-ping-type = Math Ping
+about-telemetry-archive-ping-header = Ping
+about-telemetry-option-group-today = Heddiw
+about-telemetry-option-group-yesterday = Ddoe
+about-telemetry-option-group-older = Hŷn
+about-telemetry-previous-ping = <<
+about-telemetry-next-ping = >>
+about-telemetry-page-title = Data Telemetreg
+about-telemetry-current-store = Storfa Gyfredol:
+about-telemetry-more-information = Chwilio am ragor o wybodaeth?
+about-telemetry-firefox-data-doc = Mae'r <a data-l10n-name="data-doc-link">Firefox Data Documentation</a> yn cynnwys canllawiau ar sut i weithio gyda'n offer data.
+about-telemetry-telemetry-client-doc = Mae <a data-l10n-name="client-doc-link">dogfennaeth cleient Firefox Telemetry</a> yn cynnwys diffiniadau o gysyniadau, dogfennaeth API a chyfeiriadau data.
+about-telemetry-telemetry-dashboard = Mae <a data-l10n-name="dashboard-link">byrddau gwaith Telemetreg</a> yn caniatáu i chi weld y data mae Mozilla yn ei dderbyn drwy'r Delemetreg.
+about-telemetry-telemetry-probe-dictionary = Mae'r <a data-l10n-name="probe-dictionary-link">Geiriadur Archwilio</a> yn darparu manylion a disgrifiadau ar gyfer y chwilio gasglwyd gan Delemetreg.
+about-telemetry-show-in-Firefox-json-viewer = Agor yn y darllenydd JSON
+about-telemetry-home-section = Cartref
+about-telemetry-general-data-section = Data Cyffredinol
+about-telemetry-environment-data-section = Data'r Amgylchedd
+about-telemetry-session-info-section = Manylion Sesiwn
+about-telemetry-scalar-section = Scalarau
+about-telemetry-keyed-scalar-section = Graddfeydd Allweddedig
+about-telemetry-histograms-section = Histogramau
+about-telemetry-keyed-histogram-section = Histogramau Allweddol
+about-telemetry-events-section = Digwyddiadau
+about-telemetry-simple-measurements-section = Mesuriadau Syml
+about-telemetry-slow-sql-section = Datganiadau SQL Araf
+about-telemetry-addon-details-section = Manylion Ychwanegyn
+about-telemetry-captured-stacks-section = Staciau wedi eu Cipio
+about-telemetry-late-writes-section = Ysgrifennu Hwyr
+about-telemetry-raw-payload-section = Llwyth Bras
+about-telemetry-raw = JSON bras
+about-telemetry-full-sql-warning = SYLW: Mae dadfygio SQL araf wedi ei alluogi. Gall llinynnau SQL llawn gael eu dangos isod ond ni fyddant yn cael eu trosglwyddo i'r Telemetreg.
+about-telemetry-fetch-stack-symbols = Estyn enwau swyddogaethau ar gyfer pentyrrau
+about-telemetry-hide-stack-symbols = Dangos data pentwr bras
+# Selects the correct release version
+# Variables:
+#   $channel (String): represents the corresponding release data string
+about-telemetry-data-type =
+    { $channel ->
+        [release] ryddhau data
+       *[prerelease] data cyn ryddhau
+    }
+# Selects the correct upload string
+# Variables:
+#   $uploadcase (String): represents a corresponding upload string
+about-telemetry-upload-type =
+    { $uploadcase ->
+        [enabled] galluogwyd
+       *[disabled] analluogwyd
+    }
+# Example Output: 1 sample, average = 0, sum = 0
+# Variables:
+#   $sampleCount (Integer): amount of histogram samples
+#   $prettyAverage (Integer): average of histogram samples
+#   $sum (Integer): sum of histogram samples
+about-telemetry-histogram-stats =
+    { $sampleCount ->
+        [zero] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+        [one] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+        [two] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+        [few] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+        [many] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+       *[other] { $sampleCount } sampl, cyfartaledd= { $prettyAverage }, swm = { $sum }
+    }
+# Variables:
+#   $telemetryServerOwner (String): the value of the toolkit.telemetry.server_owner preference. Typically "Mozilla"
+about-telemetry-page-subtitle = Mae'r dudalen hon yn dangos gwybodaeth am berfformiad, caledwedd, defnydd a chyfaddasiadau a gasglwyd gan y Delemetreg. Mae'r wybodaeth yn cael ei gyflwyno i { $telemetryServerOwner } er mwyn gwella { -brand-full-name }.
+about-telemetry-settings-explanation = Mae telemetreg yn casglu { about-telemetry-data-type } a'r llwyth yw <a data-l10n-name="upload-link">{ about-telemetry-upload-type }</a>.
+# Variables:
+#   $name (String): ping name, e.g. “saved-session”
+#   $timeStamp (String): ping localized timestamp, e.g. “2017/07/08 10:40:46”
+about-telemetry-ping-details = Mae pob darn o wybodaeth wedi ei anfon wedi ei becynnu i “<a data-l10n-name="ping-link">pingiau</a>”. Rydych yn edrych ar ping { $name }, { $timestamp }.
+about-telemetry-data-details-current = Mae pob darn o wybodaeth yn cael ei anfon wedi'i fwndelu i “<a data-l10n-name="ping-link">bingiadau</a>“. Rydych yn edrych ar y data cyfredol.
+# string used as a placeholder for the search field
+# More info about it can be found here:
+# https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/telemetry/data/main-ping.html
+# Variables:
+#   $selectedTitle (String): the section name from the structure of the ping.
+about-telemetry-filter-placeholder =
+    .placeholder = Canfod yn y { $selectedTitle }
+about-telemetry-filter-all-placeholder =
+    .placeholder = Canfod ym mhob adran
+# Variables:
+#   $searchTerms (String): the searched terms
+about-telemetry-results-for-search = Canlyniadau “{ $searchTerms }”
+# More info about it can be found here: https://firefox-source-docs.mozilla.org/toolkit/components/telemetry/telemetry/data/main-ping.html
+# Variables:
+#   $sectionName (String): the section name from the structure of the ping.
+#   $currentSearchText (String): the current text in the search input
+about-telemetry-no-search-results = Ymddiheuriadau! Does dim canlyniadau yn { $sectionName } ar gyfer “{ $currentSearchText }”
+# Variables:
+#   $searchTerms (String): the searched terms
+about-telemetry-no-search-results-all = Ymddiheuriadau! Nid oes canlyniadau i unrhyw adran am “{ $searchTerms }”
+# This message is displayed when a section is empty.
+# Variables:
+#   $sectionName (String): is replaced by the section name.
+about-telemetry-no-data-to-display = Ymddiheuriadau! Nid oes data ar gael ar hyn o bryd yn “{ $sectionName }”
+# used as a tooltip for the “current” ping title in the sidebar
+about-telemetry-current-data-sidebar = data cyfredol
+# used in the “Ping Type” select
+about-telemetry-telemetry-ping-type-all = popeth
+# button label to copy the histogram
+about-telemetry-histogram-copy = Copïo
+# these strings are used in the “Slow SQL Statements” section
+about-telemetry-slow-sql-main = Datganiadau SQL Araf ar y Prif Drywydd
+about-telemetry-slow-sql-other = Datganiadau SQL Araf ar y Trywyddion Cynorthwyol
+about-telemetry-slow-sql-hits = Trawiadau
+about-telemetry-slow-sql-average = Amser Cyfartalog (ms)
+about-telemetry-slow-sql-statement = Datganiad
+# these strings are used in the “Add-on Details” section
+about-telemetry-addon-table-id = Enw'r Ychwanegyn
+about-telemetry-addon-table-details = Manylion
+# Variables:
+#   $addonProvider (String): the name of an Add-on Provider (e.g. “XPI”, “Plugin”)
+about-telemetry-addon-provider = Darparwr { $addonProvider }
+about-telemetry-keys-header = Priodwedd
+about-telemetry-names-header = Enw
+about-telemetry-values-header = Gwerth
+# Variables:
+#   $stackKey (String): the string key for this stack
+#   $capturedStacksCount (Integer):  the number of times this stack was captured
+about-telemetry-captured-stacks-title = { $stackKey } (cyfrif cipio: { $capturedStacksCount })
+# Variables:
+#   $lateWriteCount (Integer): the number of the late writes
+about-telemetry-late-writes-title = Ysgrifennu Hwyr #{ $lateWriteCount }
+about-telemetry-stack-title = Stac:
+about-telemetry-memory-map-title = Map cof:
+about-telemetry-error-fetching-symbols = Digwyddodd gwall wrth estyn symbolau. Gwiriwch eich bod wedi eich cysylltu â'r rhyngrwyd a cheisio eto.
+about-telemetry-time-stamp-header = stamp amser
+about-telemetry-category-header = categori
+about-telemetry-method-header = dull
+about-telemetry-object-header = gwrthrych
+about-telemetry-extra-header = ychwanegol
+about-telemetry-origin-section = Telemetreg y Tarddiad
+about-telemetry-origin-origin = tarddiad
+about-telemetry-origin-count = cyfrif
+# Variables:
+#   $telemetryServerOwner (String): the value of the toolkit.telemetry.server_owner preference. Typically "Mozilla"
+about-telemetry-origins-explanation = Mae <a data-l10n-name="origin-doc-link">Firefox Origin Telemetry</a> yn amgodio data cyn iddo gael ei anfon fel bod { $telemetryServerOwner } yn gallu cyfrif pethau, ond heb wybod a yw { -brand-product-name } wedi cyfrannu i'r cyfrif hwnnw. (<a data-l10n-name="prio-blog-link">Dysgu rhagor</a>)
+# Variables:
+#  $process (String): type of process in subsection headers ( e.g. "content", "parent" )
+about-telemetry-process = Proses { $process }
diff --git a/l10n-cy/toolkit/toolkit/about/aboutWebrtc.ftl b/l10n-cy/toolkit/toolkit/about/aboutWebrtc.ftl
new file mode 100644
index 0000000000..8cedc061c8
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutWebrtc.ftl
@@ -0,0 +1,255 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### Localization for about:webrtc, a troubleshooting and diagnostic page
+### for WebRTC calls. See https://developer.mozilla.org/en-US/docs/Web/API/WebRTC_API.
+
+# The text "WebRTC" is a proper noun and should not be translated.
+about-webrtc-document-title = Materion Mewnol WebRTC
+# "about:webrtc" is a internal browser URL and should not be
+# translated. This string is used as a title for a file save dialog box.
+about-webrtc-save-page-dialog-title = cadw about:webrtc fel
+
+## AEC is an abbreviation for Acoustic Echo Cancellation.
+
+about-webrtc-aec-logging-msg-label = Cofnodi AEC
+about-webrtc-aec-logging-off-state-label = Cychwyn Cofnodi AEC
+about-webrtc-aec-logging-on-state-label = Atal Cofnodi AEC
+about-webrtc-aec-logging-on-state-msg = Cofnodi AEC yn weithredol (siarad gyda'r galwr am ychydig funudau ac yna atal y cipio)
+
+##
+
+# "PeerConnection" is a proper noun associated with the WebRTC module. "ID" is
+# an abbreviation for Identifier. This string should not normally be translated
+# and is used as a data label.
+about-webrtc-peerconnection-id-label = Dynodiad PeerConnection:
+
+## "SDP" is an abbreviation for Session Description Protocol, an IETF standard.
+## See http://wikipedia.org/wiki/Session_Description_Protocol
+
+about-webrtc-sdp-heading = SDP
+about-webrtc-local-sdp-heading = SDP lleol
+about-webrtc-local-sdp-heading-offer = SDP lleol (Cynnig)
+about-webrtc-local-sdp-heading-answer = SDP lleol (Ateb)
+about-webrtc-remote-sdp-heading = SDP pell
+about-webrtc-remote-sdp-heading-offer = SDP pell (Cynnig)
+about-webrtc-remote-sdp-heading-answer = SDP pell (Ateb)
+about-webrtc-sdp-history-heading = Hanes SDP
+about-webrtc-sdp-parsing-errors-heading = Gwallau Didoli SDP
+
+##
+
+# "RTP" is an abbreviation for the Real-time Transport Protocol, an IETF
+# specification, and should not normally be translated. "Stats" is an
+# abbreviation for Statistics.
+about-webrtc-rtp-stats-heading = Ystadegau RTP
+
+## "ICE" is an abbreviation for Interactive Connectivity Establishment, which
+## is an IETF protocol, and should not normally be translated.
+
+about-webrtc-ice-state = Cyflwr ICE
+# "Stats" is an abbreviation for Statistics.
+about-webrtc-ice-stats-heading = Ystadegau ICE
+about-webrtc-ice-restart-count-label = Ailgychwyn ICE:
+about-webrtc-ice-rollback-count-label = Hen fersiynau ICE:
+about-webrtc-ice-pair-bytes-sent = Didau wedi'u hanfon:
+about-webrtc-ice-pair-bytes-received = Didau wedi'u derbyn:
+about-webrtc-ice-component-id = Enw'r Cydran
+
+##
+
+
+## "Avg." is an abbreviation for Average. These are used as data labels.
+
+about-webrtc-avg-bitrate-label = Di-radd cyfartalog:
+about-webrtc-avg-framerate-label = Ffrâm-radd cyfartalog:
+
+##
+
+
+## These adjectives are used to label a line of statistics collected for a peer
+## connection. The data represents either the local or remote end of the
+## connection.
+
+about-webrtc-type-local = Lleol
+about-webrtc-type-remote = Pell
+
+##
+
+# This adjective is used to label a table column. Cells in this column contain
+# the localized javascript string representation of "true" or are left blank.
+about-webrtc-nominated = Enwebwyd
+# This adjective is used to label a table column. Cells in this column contain
+# the localized javascript string representation of "true" or are left blank.
+# This represents an attribute of an ICE candidate.
+about-webrtc-selected = Dewiswyd
+about-webrtc-save-page-label = Cadw Tudalen
+about-webrtc-debug-mode-msg-label = Modd Dadfygio
+about-webrtc-debug-mode-off-state-label = Cychwyn y Modd Dadfygio
+about-webrtc-debug-mode-on-state-label = Atal y Modd Dadfygio
+about-webrtc-stats-heading = Ystadegau'r Sesiwn
+about-webrtc-stats-clear = Clirio Hanes
+about-webrtc-log-heading = Cofnod Cysylltu
+about-webrtc-log-clear = Clirio'r Cofnod
+about-webrtc-log-show-msg = dangos cofnod
+    .title = cliciwch i ehangu'r adran
+about-webrtc-log-hide-msg = cuddio cofnod
+    .title = cliciwch i gau'r adran
+
+## These are used to display a header for a PeerConnection.
+## Variables:
+##  $browser-id (Number) - A numeric id identifying the browser tab for the PeerConnection.
+##  $id (String) - A globally unique identifier for the PeerConnection.
+##  $url (String) - The url of the site which opened the PeerConnection.
+##  $now (Date) - The JavaScript timestamp at the time the report was generated.
+
+about-webrtc-connection-open = [ { $browser-id } | { $id } ] { $url } { $now }
+about-webrtc-connection-closed = [ { $browser-id } | { $id } ] { $url } (cau) { $now }
+
+##
+
+about-webrtc-local-candidate = Ymgeisydd Lleol
+about-webrtc-remote-candidate = Ymgeisydd Pell
+about-webrtc-raw-candidates-heading = Pob Ymgeisydd Bras
+about-webrtc-raw-local-candidate = Ymgeisydd Lleol Bras
+about-webrtc-raw-remote-candidate = Ymgeisydd Pell Bras
+about-webrtc-raw-cand-show-msg = dangos ymgeiswyr bras
+    .title = cliciwch i ehangu'r adran
+about-webrtc-raw-cand-hide-msg = cuddio ymgeiswyr bras
+    .title = cliciwch i gau'r adran
+about-webrtc-priority = Blaenoriaeth
+about-webrtc-fold-show-msg = dangos manylion
+    .title = cliciwch i ehangu'r adran
+about-webrtc-fold-hide-msg = cuddio manylion
+    .title = cliciwch i gau'r adran
+about-webrtc-dropped-frames-label = Fframiau wedi'u gollwng:
+about-webrtc-discarded-packets-label = Pecynnau wedi'u hepgor:
+about-webrtc-decoder-label = Datgodwyr
+about-webrtc-encoder-label = Amgodiwr
+about-webrtc-show-tab-label = Dangos tab
+about-webrtc-width-px = Lled (px)
+about-webrtc-height-px = Uchder (px)
+about-webrtc-consecutive-frames = Fframiau Olynol
+about-webrtc-time-elapsed = Amser wedi Pasio
+about-webrtc-estimated-framerate = Amcan o Raddfa Ffrâm
+about-webrtc-rotation-degrees = Cylchdroi (graddau)
+about-webrtc-first-frame-timestamp = Stamp Amser Derbyn y  Ffrâm Gyntaf
+about-webrtc-last-frame-timestamp = Stamp Amser Derbyn y  Ffrâm Olaf
+
+## SSRCs are identifiers that represent endpoints in an RTP stream
+
+# This is an SSRC on the local side of the connection that is receiving RTP
+about-webrtc-local-receive-ssrc = Derbyn SSRC  Lleol
+# This is an SSRC on the remote side of the connection that is sending RTP
+about-webrtc-remote-send-ssrc = Anfon SSRC o Bell
+
+##
+
+# An option whose value will not be displayed but instead noted as having been
+# provided
+about-webrtc-configuration-element-provided = Wedi'i Ddarparu
+# An option whose value will not be displayed but instead noted as having not
+# been provided
+about-webrtc-configuration-element-not-provided = Heb ei Ddarparu
+# The options set by the user in about:config that could impact a WebRTC call
+about-webrtc-custom-webrtc-configuration-heading = Dewisiadau WebRTC Gosodedig y Defnyddiwr
+# Section header for estimated bandwidths of WebRTC media flows
+about-webrtc-bandwidth-stats-heading = Amcangyfrif Lled Band
+# The ID of the MediaStreamTrack
+about-webrtc-track-identifier = Dynodwr tracio
+# The estimated bandwidth available for sending WebRTC media in bytes per second
+about-webrtc-send-bandwidth-bytes-sec = Lled Band Anfon (beit/eiliad)
+# The estimated bandwidth available for receiving WebRTC media in bytes per second
+about-webrtc-receive-bandwidth-bytes-sec = Lled Band Derbyn (beit/eiliad)
+# Maximum number of bytes per second that will be padding zeros at the ends of packets
+about-webrtc-max-padding-bytes-sec = Uchafswm Padio (beit/eiliad)
+# The amount of time inserted between packets to keep them spaced out
+about-webrtc-pacer-delay-ms = Oedi Pacer ms
+# The amount of time it takes for a packet to travel from the local machine to the remote machine,
+# and then have a packet return
+about-webrtc-round-trip-time-ms = RTT ms
+# This is a section heading for video frame statistics for a MediaStreamTrack.
+# see https://developer.mozilla.org/en-US/docs/Web/API/MediaStreamTrack.
+# Variables:
+#   $track-identifier (String) - The unique identifier for the MediaStreamTrack.
+about-webrtc-frame-stats-heading = Ystadegau Ffrâm Fideo - MediaStreamTrack ID: { $track-identifier }
+
+## These are paths used for saving the about:webrtc page or log files so
+## they can be attached to bug reports.
+## Variables:
+##  $path (String) - The path to which the file is saved.
+
+about-webrtc-save-page-msg = cadwyd y dudalen i: { $path }
+about-webrtc-debug-mode-off-state-msg = mae modd canfod y cofnod olrhain yn: { $path }
+about-webrtc-debug-mode-on-state-msg = modd dadfygio'n weithredol, cofnod olrhain yn { $path }
+about-webrtc-aec-logging-off-state-msg = mae'r ffeiliau cofnod y cipio yn: { $path }
+
+##
+
+# This is the total number of packets received on the PeerConnection.
+# Variables:
+#  $packets (Number) - The number of packets received.
+about-webrtc-received-label =
+    { $packets ->
+        [zero] Heb dderbyn unrhyw becyn
+        [one] Wedi derbyn { $packets } pecyn
+        [two] Wedi derbyn { $packets } pecyn
+        [few] Wedi derbyn { $packets } pecyn
+        [many] Wedi derbyn { $packets } pecyn
+       *[other] Wedi derbyn { $packets } pecyn
+    }
+# This is the total number of packets lost by the PeerConnection.
+# Variables:
+#  $packets (Number) - The number of packets lost.
+about-webrtc-lost-label =
+    { $packets ->
+        [zero] Heb golli unrhyw becyn
+        [one] Wedi derbyn { $packets } pecyn
+        [two] Wedi derbyn { $packets } pecyn
+        [few] Wedi derbyn { $packets } pecyn
+        [many] Wedi derbyn { $packets } pecyn
+       *[other] Wedi derbyn { $packets } pecyn
+    }
+# This is the total number of packets sent by the PeerConnection.
+# Variables:
+#  $packets (Number) - The number of packets sent.
+about-webrtc-sent-label =
+    { $packets ->
+        [zero] Heb anfon unrhyw becyn
+        [one] Wedi anfon { $packets } pecyn
+        [two] Wedi anfon { $packets } pecyn
+        [few] Wedi anfon { $packets } pecyn
+        [many] Wedi anfon { $packets } pecyn
+       *[other] Wedi anfon { $packets } pecyn
+    }
+# Jitter is the variance in the arrival time of packets.
+# See: https://w3c.github.io/webrtc-stats/#dom-rtcreceivedrtpstreamstats-jitter
+# Variables:
+#   $jitter (Number) - The jitter.
+about-webrtc-jitter-label = Jitter { $jitter }
+# ICE candidates arriving after the remote answer arrives are considered trickled
+# (an attribute of an ICE candidate). These are highlighted in the ICE stats
+# table with light blue background.
+about-webrtc-trickle-caption-msg = Mae ymgeisydd diferu (yn cyrraedd ar ôl yr ateb) yn cael eu hamlygu mewn glas
+
+## "SDP" is an abbreviation for Session Description Protocol, an IETF standard.
+## See http://wikipedia.org/wiki/Session_Description_Protocol
+
+# This is used as a header for local SDP.
+# Variables:
+#  $timestamp (Number) - The Unix Epoch time at which the SDP was set.
+about-webrtc-sdp-set-at-timestamp-local = Gosod SDP lleol ar y stamp amser { NUMBER($timestamp, useGrouping: "false") }.
+# This is used as a header for remote SDP.
+# Variables:
+#  $timestamp (Number) - The Unix Epoch time at which the SDP was set.
+about-webrtc-sdp-set-at-timestamp-remote = Gosod SDP pell ar y stamp amser { NUMBER($timestamp, useGrouping: "false") }.
+# This is used as a header for an SDP section contained in two columns allowing for side-by-side comparisons.
+# Variables:
+#  $timestamp (Number) - The Unix Epoch time at which the SDP was set.
+#  $relative-timestamp (Number) - The timestamp relative to the timestamp of the earliest received SDP.
+about-webrtc-sdp-set-timestamp = Stamp amser { NUMBER($timestamp, useGrouping: "false") } (+ { $relative-timestamp } ms)
+
+##
+
diff --git a/l10n-cy/toolkit/toolkit/about/abuseReports.ftl b/l10n-cy/toolkit/toolkit/about/abuseReports.ftl
new file mode 100644
index 0000000000..c05339c2a8
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/abuseReports.ftl
@@ -0,0 +1,101 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Localized string used as the dialog window title (a new behavior locked
+# behind the "extensions.abuseReport.openDialog" preference).
+# "Report" is a noun in this case, "Report for AddonName".
+#
+# Variables:
+#   $addon-name (string) - Name of the add-on being reported
+abuse-report-dialog-title = Adrodd am { $addon-name }
+
+abuse-report-title-extension = Adroddwch yr Estyniad hwn i { -vendor-short-name }
+abuse-report-title-theme = Adroddwch y Thema hon i { -vendor-short-name }
+abuse-report-subtitle = Beth yw'r broblem?
+
+# Variables:
+#   $author-name (string) - Name of the add-on author
+abuse-report-addon-authored-by = gan <a data-l10n-name="author-name">{ $author-name }</a>
+
+abuse-report-learnmore =
+    Ddim yn siŵr pa fater i'w ddewis?
+    <a data-l10n-name="learnmore-link">Dysgwch fwy am adrodd ar estyniadau a themâu</a>
+
+abuse-report-submit-description = Disgrifiwch y broblem (dewisol)
+abuse-report-textarea =
+    .placeholder = Mae'n haws i ni fynd i'r afael â phroblem os oes gennym fanylion penodol. Disgrifiwch yr hyn rydych chi'n ei brofi. Diolch i chi am ein helpu i gadw'r we'n iach.
+abuse-report-submit-note =
+    Sylwer: Peidiwch â chynnwys gwybodaeth bersonol (fel enw, cyfeiriad e-bost, rhif ffôn, cyfeiriad corfforol).
+    Mae { -vendor-short-name } yn cadw cofnod parhaol o'r adroddiadau hyn.
+
+## Panel buttons.
+
+abuse-report-cancel-button = Diddymu
+abuse-report-next-button = Nesaf
+abuse-report-goback-button = Mynd nôl
+abuse-report-submit-button = Cyflwyno
+
+## Message bars descriptions.
+
+
+## Variables:
+##   $addon-name (string) - Name of the add-on
+
+abuse-report-messagebar-aborted = Diddymwyd yr adroddiad ar gyfer <span data-l10n-name="addon-name">{ $addon-name }</span>>.
+abuse-report-messagebar-submitting = Anfon adroddiad ar gyfer <span data-l10n-name="addon-name">{ $addon-name }</span>.
+abuse-report-messagebar-submitted = Diolch i chi am gyflwyno adroddiad. Ydych chi am gael gwared ar <span data-l10n-name="addon-name">{ $addon-name }</span>?
+abuse-report-messagebar-submitted-noremove = Diolch am gyflwyno adroddiad.
+abuse-report-messagebar-removed-extension = Diolch i chi am gyflwyno adroddiad. Rydych wedi tynnu'r estyniad <span data-l10n-name="addon-name">{ $addon-name }</span>.
+abuse-report-messagebar-removed-theme = Diolch i chi am gyflwyno adroddiad. Rydych chi wedi tynnu'r thema <span data-l10n-name="addon-name">{ $addon-name }</span>
+abuse-report-messagebar-error = Roedd gwall wrth anfon yr adroddiad ar gyfer <span data-l10n-name="addon-name">{ $addon-name }</span>.
+abuse-report-messagebar-error-recent-submit = Nid yw'r adroddiad ar gyfer <span data-l10n-name="addon-name">{ $addon-name }</span> wedi ei anfon oherwydd bod adroddiad arall wedi'i gyflwyno'n ddiweddar.
+
+## Message bars actions.
+
+abuse-report-messagebar-action-remove-extension = Iawn, Dileu
+abuse-report-messagebar-action-keep-extension = Na, rwyf am ei gadw
+abuse-report-messagebar-action-remove-theme = Iawn, Dileu
+abuse-report-messagebar-action-keep-theme = Na, rwyf am ei gadw
+abuse-report-messagebar-action-retry = Ceisio eto
+abuse-report-messagebar-action-cancel = Diddymu
+
+## Abuse report reasons (optionally paired with related examples and/or suggestions)
+
+abuse-report-damage-reason-v2 = Fe wnaeth niweidio fy nghyfrifiadur neu gyfaddawdu ar fy nata
+abuse-report-damage-example = Enghraifft: Chwistrellu data maleisus neu ddata wedi'i ddwyn
+
+abuse-report-spam-reason-v2 = Mae'n cynnwys sbam neu'n mewnosod hysbysebu dieisiau
+abuse-report-spam-example = Enghraifft: Mewnosod hysbysebion ar dudalennau gwe
+
+abuse-report-settings-reason-v2 = Newidiodd fy mheiriant chwilio, hafan, neu dab newydd heb roi gwybod na gofyn imi
+abuse-report-settings-suggestions = Cyn adrodd ar yr estyniad, gallwch roi cynnig ar newid eich gosodiadau:
+abuse-report-settings-suggestions-search = Newid eich gosodiadau chwilio rhagosodedig
+abuse-report-settings-suggestions-homepage = Newidiwch eich tudalen gartref a'ch tab newydd
+
+abuse-report-deceptive-reason-v2 = Mae'n honni ei fod yn rhywbeth nad ydyw
+abuse-report-deceptive-example = Enghraifft: Disgrifiad neu ddelweddau camarweiniol
+
+abuse-report-broken-reason-extension-v2 = Nid yw'n gweithio, mae'n torri gwefannau, neu'n arafu { -brand-product-name }
+abuse-report-broken-reason-theme-v2 = Nid yw'n gweithio nac yn torri dangosydd y porwr
+abuse-report-broken-example = Enghraifft: Mae nodwedd yn araf, yn anodd ei defnyddio, neu ddim yn gweithio; ni fydd rhannau o wefannau yn llwytho neu'n edrych yn rhyfedd
+abuse-report-broken-suggestions-extension =
+    Mae'n edrych fel eich bod wedi adnabod gwall. Yn ogystal â chyflwyno adroddiad yma, y ffordd orau
+    orau i ddatrys mater ymarferoldeb wedi'i ddatrys yw cysylltu â datblygwr yr estyniad.
+    <a data-l10n-name="support-link">Ewch i wefan yr estyniad</a> i gael gwybodaeth gan y datblygwr.
+abuse-report-broken-suggestions-theme =
+    Mae'n edrych fel eich bod wedi adnabod gwall. Yn ogystal â chyflwyno adroddiad yma, y ffordd orau
+    orau i ddatrys mater ymarferoldeb wedi'i ddatrys yw cysylltu â datblygwr y thema.
+    <a data-l10n-name="support-link"> Ewch i wefan y thema </a> i gael gwybodaeth y datblygwr.
+
+abuse-report-policy-reason-v2 = Mae'n cynnwys cynnwys atgas, treisgar neu anghyfreithlon
+abuse-report-policy-suggestions =
+    Sylw: Rhaid rhoi gwybod am faterion hawlfraint a nod masnach mewn proses ar wahân.
+    <a data-l10n-name="report-infringement-link"> Defnyddiwch y cyfarwyddiadau hyn</a> i
+    adrodd am y broblem.
+
+abuse-report-unwanted-reason-v2 = Doeddwn i erioed ei eisiau ac nid wyf yn gwybod sut i gael gwared arno
+abuse-report-unwanted-example = Enghraifft: Gosodwyd y rhaglen heb fy nghaniatâd
+
+abuse-report-other-reason = Rhywbeth arall
+
diff --git a/l10n-cy/toolkit/toolkit/about/certviewer.ftl b/l10n-cy/toolkit/toolkit/about/certviewer.ftl
new file mode 100644
index 0000000000..7ddb427143
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/certviewer.ftl
@@ -0,0 +1,120 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+certificate-viewer-certificate-section-title = Tystysgrif
+
+## Error messages
+
+certificate-viewer-error-message = Nid oeddem yn gallu dod o hyd i fanylion y dystysgrif, neu mae'r dystysgrif yn llygredig. Ceisiwch eto.
+certificate-viewer-error-title = Aeth rhywbeth o'i le.
+
+## Certificate information labels
+
+certificate-viewer-algorithm = Algorithm
+certificate-viewer-certificate-authority = Awdurdod Tystysgrif
+certificate-viewer-cipher-suite = Casgliad Seiffr
+certificate-viewer-common-name = Enw Cyffredin
+certificate-viewer-email-address = Cyfeiriad E-bost
+# Variables:
+#   $firstCertName (String) - Common Name for the displayed certificate
+certificate-viewer-tab-title = Tystysgrif ar gyfer { $firstCertName }
+# Inc. means Incorporated, e.g GitHub is incorporated in Delaware
+certificate-viewer-inc-country = Gwlad Corfforedig
+certificate-viewer-country = Gwlad
+certificate-viewer-curve = Cromlin
+certificate-viewer-distribution-point = Pwynt Dosbarthu
+certificate-viewer-dns-name = Enw DNS
+certificate-viewer-ip-address = Cyfeiriad IP
+certificate-viewer-other-name = Enw Arall
+certificate-viewer-exponent = Esbonydd
+certificate-viewer-id = ID
+certificate-viewer-key-exchange-group = Grŵp Cyfnewid Allwedd
+certificate-viewer-key-id = ID Allwedd
+certificate-viewer-key-size = Maint Allwedd
+# Inc. means Incorporated, e.g GitHub is incorporated in Delaware
+certificate-viewer-inc-locality = Ardal Corffori
+certificate-viewer-locality = Lleoliad
+certificate-viewer-location = Lleoliad
+certificate-viewer-logid = ID Cofnod
+certificate-viewer-method = Dull
+certificate-viewer-modulus = Modwlws
+certificate-viewer-name = Enw
+certificate-viewer-not-after = Nid ar Ôl
+certificate-viewer-not-before = Nid Cyn
+certificate-viewer-organization = Corff
+certificate-viewer-organizational-unit = Uned Corff
+certificate-viewer-policy = Polisi
+certificate-viewer-protocol = Protocol
+certificate-viewer-public-value = Gwerth Cyhoeddus
+certificate-viewer-purposes = Pwrpasau
+certificate-viewer-qualifier = Cymhwyster
+certificate-viewer-qualifiers = Cymhwysterau
+certificate-viewer-required = Gofynnol
+certificate-viewer-unsupported = &lt;heb ei gynnal&gt;
+# Inc. means Incorporated, e.g GitHub is incorporated in Delaware
+certificate-viewer-inc-state-province = Corfforedig Talaith/Ardal
+certificate-viewer-state-province = Talaith/Ardal
+certificate-viewer-sha-1 = SHA-1
+certificate-viewer-sha-256 = SHA-256
+certificate-viewer-serial-number = Rhif Cyfresol
+certificate-viewer-signature-algorithm = Algorithm Llofnod
+certificate-viewer-signature-scheme = Cynllun Llofnod
+certificate-viewer-timestamp = Stamp Amser
+certificate-viewer-value = Gwerth
+certificate-viewer-version = Fersiwn
+certificate-viewer-business-category = Categori Busnes
+certificate-viewer-subject-name = Enw'r Pwnc
+certificate-viewer-issuer-name = Enw Cyhoeddwr
+certificate-viewer-validity = Dilysrwydd
+certificate-viewer-subject-alt-names = Enwau Alt Pwnc
+certificate-viewer-public-key-info = Manylion Allweddol Cyhoeddus
+certificate-viewer-miscellaneous = Amrywiol
+certificate-viewer-fingerprints = Bysbrint
+certificate-viewer-basic-constraints = Cyfyngiadau Sylfaenol
+certificate-viewer-key-usages = Defnyddiau Allweddol
+certificate-viewer-extended-key-usages = Defnydd Allwedd Estynedig
+certificate-viewer-ocsp-stapling = Strapio OCSP
+certificate-viewer-subject-key-id = ID Allwedd Pwnc
+certificate-viewer-authority-key-id = ID Allwedd yr Awdurdod
+certificate-viewer-authority-info-aia = Manylion yr Awdurdod (AIA)
+certificate-viewer-certificate-policies = Polisïau Tystysgrif
+certificate-viewer-embedded-scts = SCTs mewnblanedig
+certificate-viewer-crl-endpoints = Diweddbwynt CRL
+# This message is used as a row header in the Miscellaneous section.
+# The associated data cell contains links to download the certificate.
+certificate-viewer-download = Llwytho i Lawr
+# This message is used to replace boolean values (true/false) in several certificate fields, e.g. Certificate Authority
+# Variables:
+#   $boolean (String) - true/false value for the specific field
+certificate-viewer-boolean =
+    { $boolean ->
+        [true] Iawn
+       *[false] na
+    }
+
+## Variables:
+##   $fileName (String) - The file name to save the PEM data in, derived from the common name from the certificate being displayed.
+
+certificate-viewer-download-pem = PEM (tystysgrif)
+    .download = { $fileName }.pem
+certificate-viewer-download-pem-chain = PEM (cadwyn)
+    .download = { $fileName }-chain.pem
+# The title attribute for Critical Extension icon
+certificate-viewer-critical-extension =
+    .title = Mae'r estyniad hwn wedi'i nodi fel un hanfodol, sy'n golygu bod yn rhaid i gleientiaid wrthod y dystysgrif os nad ydyn nhw'n ei deall.
+certificate-viewer-export = Allforio
+    .download = { $fileName }.pem
+
+##
+
+# Label for a tab where we haven't found a better label:
+certificate-viewer-unknown-group-label = (anhysbys)
+
+## Labels for tabs displayed in stand-alone about:certificate page
+
+certificate-viewer-tab-mine = Eich Tystysgrifau
+certificate-viewer-tab-people = Pobl
+certificate-viewer-tab-servers = Gweinyddion
+certificate-viewer-tab-ca = Awdurdodau
+certificate-viewer-tab-unkonwn = Anhysbys
diff --git a/l10n-cy/toolkit/toolkit/about/config.ftl b/l10n-cy/toolkit/toolkit/about/config.ftl
new file mode 100644
index 0000000000..d9621d4a2c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/config.ftl
@@ -0,0 +1,51 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## These strings appear on the warning you see when first visiting about:config.
+
+about-config-intro-warning-title = Byddwch Ofalus
+about-config-intro-warning-text = Gall newid dewisiadau ffurfweddiad uwch effeithio ar berfformiad neu ddiogelwch { -brand-short-name }.
+about-config-intro-warning-checkbox = Rhybuddiwch fi pan fyddaf yn ceisio mynd at y dewisiadau hyn
+about-config-intro-warning-button = Derbyn y Perygl a Pharhau
+
+##
+
+# This is shown on the page before searching but after the warning is accepted.
+about-config-caution-text = Gall newid dewisiadau ffurfweddiad uwch effeithio ar berfformiad neu ddiogelwch { -brand-short-name }.
+about-config-page-title = Dewisiadau Uwch
+about-config-search-input1 =
+    .placeholder = Enw dewis chwilio
+about-config-show-all = Dangos Popeth
+about-config-show-only-modified = Dangos dewisiadau wedi'u haddasu yn unig
+about-config-pref-add-button =
+    .title = Ychwanegu
+about-config-pref-toggle-button =
+    .title = Toglo
+about-config-pref-edit-button =
+    .title = Golygu
+about-config-pref-save-button =
+    .title = Cadw
+about-config-pref-reset-button =
+    .title = Ailosod
+about-config-pref-delete-button =
+    .title = Dileu
+
+## Labels for the type selection radio buttons shown when adding preferences.
+
+about-config-pref-add-type-boolean = Boole
+about-config-pref-add-type-number = Rhif
+about-config-pref-add-type-string = Llinyn
+
+## Preferences with a non-default value are differentiated visually, and at the
+## same time the state is made accessible to screen readers using an aria-label
+## that won't be visible or copied to the clipboard.
+##
+## Variables:
+##   $value (String): The full value of the preference.
+
+about-config-pref-accessible-value-default =
+    .aria-label = { $value } (default)
+about-config-pref-accessible-value-custom =
+    .aria-label = { $value } (custom)
diff --git a/l10n-cy/toolkit/toolkit/about/url-classifier.ftl b/l10n-cy/toolkit/toolkit/about/url-classifier.ftl
new file mode 100644
index 0000000000..0c91ecb91e
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/url-classifier.ftl
@@ -0,0 +1,54 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+url-classifier-title = Manylion Dosbarthu URL
+url-classifier-search-title = Chwilio
+url-classifier-search-result-title = Canlyniadau
+url-classifier-search-result-uri = URI: { $uri }
+url-classifier-search-result-list = Rhestr tablau: { $list }
+url-classifier-search-input = URL
+url-classifier-search-error-invalid-url = URL annilys
+url-classifier-search-error-no-features = Heb ddewis nodwedd
+url-classifier-search-btn = Cychwyn chwilio
+url-classifier-search-features = Nodweddion
+url-classifier-search-listType = Math o restr
+url-classifier-provider-title = Darparwr
+url-classifier-provider = Darparwr
+url-classifier-provider-last-update-time = Amser y diweddariad diwethaf
+url-classifier-provider-next-update-time = Amser y diweddariad nesaf
+url-classifier-provider-back-off-time = Amser atal
+url-classifier-provider-last-update-status = Statws y diweddariad diwethaf
+url-classifier-provider-update-btn = Diweddaru
+url-classifier-cache-title = Storfa Dros Dro
+url-classifier-cache-refresh-btn = Adnewyddu
+url-classifier-cache-clear-btn = Clirio
+url-classifier-cache-table-name = Enw tabl
+url-classifier-cache-ncache-entries = Nifer o gofnodion storfa dros dro negyddol
+url-classifier-cache-pcache-entries = Nifer o gofnodion storfa dros dro negyddol
+url-classifier-cache-show-entries = Dangos y cofnodion
+url-classifier-cache-entries = Cofnodion Storfa Dros Dro
+url-classifier-cache-prefix = Rhagddodiad
+url-classifier-cache-ncache-expiry = Storfa dros dro negyddol yn dod i ben
+url-classifier-cache-fullhash = Hash llawn
+url-classifier-cache-pcache-expiry = Storfa dros dro positif yn dod i ben
+url-classifier-debug-title = Dadfygio
+url-classifier-debug-module-btn = Gosod Modiwlau Cofnodi
+url-classifier-debug-file-btn = Gosod Ffeil Cofnodi
+url-classifier-debug-js-log-chk = Gosod Cofnod JS
+url-classifier-debug-sb-modules = Modiwlau cofnodi Pori Diogel
+url-classifier-debug-modules = Y modiwlau cofnodi cyfredol
+url-classifier-debug-sbjs-modules = Cofnod Pori Diogel JS
+url-classifier-debug-file = Ffeil cofnod cyfredol
+
+url-classifier-trigger-update = Diweddariad Triger
+url-classifier-not-available = Dim Ar Gael
+url-classifier-disable-sbjs-log = Analluogi Cofnod JS Pori Diogel
+url-classifier-enable-sbjs-log = Galluogi Cofnod JS Pori Diogel
+url-classifier-enabled = Galluogwyd
+url-classifier-disabled = Analluogwyd
+url-classifier-updating = diweddaru
+url-classifier-cannot-update = methu diweddaru
+url-classifier-success = llwyddiant
+url-classifier-update-error = gwall diweddaru ({ $error })
+url-classifier-download-error = gwall llwytho i lawr ({ $error })
diff --git a/l10n-cy/toolkit/toolkit/extensions/blocklist.ftl b/l10n-cy/toolkit/toolkit/extensions/blocklist.ftl
new file mode 100644
index 0000000000..efec01a975
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/extensions/blocklist.ftl
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0
+
+blocklist-window =
+    .title = Mae Ychwanegion yn gallu achosi problemau
+    .style = width: 45em; height: 30em
+blocklist-accept =
+    .label = Ailgychwyn { -brand-short-name }
+    .accesskey = A
+
+blocklist-label-summary = Mae { -brand-short-name } wedi canfod fod yr ychwanegion canlynol yn gallu creu ansefydlogrwydd neu broblemau diogelwch:
+blocklist-soft-and-hard = Mae'r ychwanegion sydd â risg uchel o achosi problemau wedi eu rhwystro. Mae'r lleill o risg is, ond argymhellir yn gryf eich bod yn ailgychwyn gyda nhw wedi eu hanalluogi.
+blocklist-hard-blocked = Mae'r ychwanegion hyn a thebygrwydd uchel o achosi problemau ac maent wedi eu rhwystro, ond bydd angen ailgychwyn i'w hanalluogi yn llwyr.
+blocklist-soft-blocked = Er eich diogelwch, argymhellir eich bod yn ailgychwyn gyda'r ychwanegion hyn wedi eu hanalluogi.
+blocklist-more-information =
+    .value = Rhagor o wybodaeth
+
+blocklist-blocked =
+    .label = Rhwystrwyd
+blocklist-checkbox =
+    .label = Anablu
diff --git a/l10n-cy/toolkit/toolkit/featuregates/features.ftl b/l10n-cy/toolkit/toolkit/featuregates/features.ftl
new file mode 100644
index 0000000000..3e0b56c79a
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/featuregates/features.ftl
@@ -0,0 +1,107 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-css-masonry2 =
+    .label = CSS: Masonry Layout
+experimental-features-css-masonry-description = Yn galluogi cefnogaeth i nodwedd arbrofol Cynllun Masonry CSS. Gw. yr <a data-l10n-name="explainer">esboniwr</a> i gael disgrifiad lefel uchel o'r nodwedd. I ddarparu adborth, rhowch sylwadau yn <a data-l10n-name="w3c-issue">y mater GitHub hwn</a> neu <a data-l10n-name="bug">y byg hwn</a>.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-web-gpu2 =
+    .label = Web API: WebGPU
+experimental-features-web-gpu-description2 = Mae'r API newydd hwn yn darparu cefnogaeth lefel isel ar gyfer perfformio cyfrifiant a rendro graffeg gan ddefnyddio <a data-l10n-name="wikipedia">Uned Prosesu Graffeg (GPU)</a> dyfais neu gyfrifiadur y defnyddiwr. Mae'r <a data-l10n-name="spec">fanyleb </a> yn dal i fod yn waith ar y gweill. Gweler <a data-l10n-name="bugzilla">bug 1602129</a> am fwy o fanylion.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-media-avif =
+    .label = Media: AVIF
+experimental-features-media-avif-description = Gyda'r nodwedd hon wedi'i galluogi, mae { -brand-short-name } yn cefnogi fformat Ffeil Delwedd AV1 (AVIF). Mae hwn yn fformat ffeil delwedd llonydd sy'n trosoli galluoedd yr algorithmau cywasgu fideo AV1 i leihau maint delwedd. Gweler <a data-l10n-name="bugzilla">bug 1443863</a> am fwy o fanylion.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-web-api-inputmode =
+    .label = Web API: inputmode
+# "inputmode" and "contenteditable" are technical terms and shouldn't be translated.
+experimental-features-web-api-inputmode-description = Mae ein gweithrediad o'r priodoledd byd-eang <a data-l10n-name="mdn-inputmode">inputmode</a> wedi'i ddiweddaru yn unol â <a data-l10n-name="whatwg">manyleb WHATWG</a>, ond mae angen i ni wneud newidiadau eraill o hyd hefyd, fel sicrhau ei fod ar gael ar gynnwys adolygadwy. Gweler <a data-l10n-name="bugzilla">bug 1205133</a> am fwy o fanylion.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-web-api-link-preload =
+    .label = Web API: <link rel="preload">
+# Do not translate "rel", "preload" or "link" here, as they are all HTML spec
+# values that do not get translated.
+experimental-features-web-api-link-preload-description = Bwriad y briodoledd <a data-l10n-name="rel">rel</a> gyda gwerth <code>"preload"</code> ar <a data-l10n-name="link">&lt;dolen&gt;</a> yw helpu i ddarparu enillion perfformiad trwy adael i chi lwytho adnoddau i lawr yn gynharach yng nghylch bywyd y dudalen, gan sicrhau eu bod ar gael yn gynharach a'u bod yn llai tebygol o rwystro rendro tudalennau. Darllenwch <a data-l10n-name="readmore">“Rhag-lwytho cynnwys gyda<code> rel =" preload "</code>”</a> neu gweler <a data-l10n-name="bugzilla">bug 1583604</a> am fwy o fanylion.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-css-focus-visible =
+    .label = CSS: Pseudo-class: :focus-visible
+experimental-features-css-focus-visible-description = Yn caniatáu i arddulliau ffocws gael eu cymhwyso i elfennau fel botymau a rheolyddion ffurf, dim ond pan fyddan nhw'n canolbwyntio gan ddefnyddio'r bysellfwrdd (e.e. wrth dabio rhwng elfennau), ac nid pan fyddan nhw'n canolbwyntio gan ddefnyddio llygoden neu ddyfais bwyntio arall. Gweler <a data-l10n-name="bugzilla">bug 1617600</a> am fwy o fanylion.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-web-api-beforeinput =
+    .label = Web API: beforeinput Event
+# The terms "beforeinput", "input", "textarea", and "contenteditable" are technical terms
+# and shouldn't be translated.
+experimental-features-web-api-beforeinput-description = Mae'r digwyddiad cyffredinol <a data-l10n-name="mdn-beforeinput">beforeinput</a> yn cael ei danio ar ddigwyddiad <a data-l10n-name="mdn-input">&lt;input&gt;</a> a < a data-l10n-name = "mdn-textarea">&lt;textarea&gt;</a> elfennau, neu unrhyw elfen y mae ei briodoledd <a data-l10n-name="mdn-contenteditable">cynnwys adolygadwy</a> wedi'i alluogi, yn union cyn i werth yr elfen newid. Mae'r digwyddiad yn caniatáu i apiau gwe ddiystyru ymddygiad rhagosodedig y porwr ar gyfer rhyngweithio â defnyddwyr, e.e., gall apiau gwe ddiddymu mewnbwn defnyddiwr yn unig ar gyfer nodau penodol neu gallan nhw addasu gludo testun â steil yn unig gydag arddulliau cymeradwy.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-css-constructable-stylesheets =
+    .label = CSS: Constructable Stylesheets
+experimental-features-css-constructable-stylesheets-description = Mae ychwanegu adeiladwr at y rhyngwyneb <a data-l10n-name="mdn-cssstylesheet">CSSStyleSheet</a> yn ogystal ag amrywiaeth o newidiadau cysylltiedig yn ei gwneud hi'n bosibl creu taflenni arddull newydd yn uniongyrchol heb orfod ychwanegu'r ddalen at yr HTML. Mae hyn yn ei gwneud hi'n llawer haws creu taflenni arddull y mae modd eu hailddefnyddio i'w defnyddio gyda <a data-l10n-name="mdn-shadowdom">Shadow DOM</a>. Gweler <a data-l10n-name="bugzilla">bug 1520690</a> am fwy o fanylion.
+experimental-features-devtools-color-scheme-simulation =
+    .label = Developer Tools: Color Scheme Simulation
+experimental-features-devtools-color-scheme-simulation-description = Yn ychwanegu opsiwn i efelychu gwahanol gynlluniau lliw sy'n eich galluogi i brofi <a data-l10n-name="mdn-preferscolorscheme">@prefers-color-scheme</a> ymholiadau cyfryngau. Mae defnyddio'r ymholiad cyfryngau hwn yn caniatáu i'ch taflen arddull ymateb i p'un a yw'n well gan y defnyddiwr ryngwyneb defnyddiwr ysgafn neu dywyll. Mae'r nodwedd hon yn caniatáu ichi brofi'ch cod heb orfod newid gosodiadau yn eich porwr (neu system weithredu, os yw'r porwr yn dilyn gosodiad cynllun lliw ar draws y system). Gweler <a data-l10n-name="bugzilla1">bug 1550804</a> a <a data-l10n-name="bugzilla2">bug 1137699</a> am fwy o fanylion.
+experimental-features-devtools-execution-context-selector =
+    .label = Developer Tools: Execution Context Selector
+experimental-features-devtools-execution-context-selector-description = Mae'r nodwedd hon yn dangos botwm ar linell orchymyn y consol sy'n caniatáu i chi newid y cyd-destun y gweithredir yr ymadrodd a nodwch ynddo. Gweler <a data-l10n-name="bugzilla1">bug 1605154</a> a <a data-l10n-name="bugzilla2">bug 1605153</a> am fwy o fanylion.
+experimental-features-devtools-compatibility-panel =
+    .label = Developer Tools: Compatibility Panel
+experimental-features-devtools-compatibility-panel-description = Panel ochr ar gyfer yr Arolygydd Tudalen sy'n dangos gwybodaeth i chi sy'n manylu ar statws cydnawsedd traws-borwr eich ap. Gweler <a data-l10n-name="bugzilla">bug 1584464</a> am fwy o fanylion.
+# Do not translate 'SameSite', 'Lax' and 'None'.
+experimental-features-cookie-samesite-lax-by-default2 =
+    .label = Cwcis: SameSite=Lax by default
+experimental-features-cookie-samesite-lax-by-default2-description = Trin cwcis fel “SameSite = Lax” by default os nad oes priodoledd “SameSite” wedi'i nodi. Rhaid i ddatblygwyr ddewis y cyflwr cyfredol o ddefnydd anghyfyngedig trwy ddewis yn benodol “SameSite = None”.
+# Do not translate 'SameSite', 'Lax' and 'None'.
+experimental-features-cookie-samesite-none-requires-secure2 =
+    .label = Cwcis: mae SameSite=none angen priodoledd ddiogel
+experimental-features-cookie-samesite-none-requires-secure2-description = Mae cwcis â phriodoledd “SameSite=None” angen y briodoledd ddiogel. Mae'r nodwedd hon yn gofyn am “Cookies: SameSite=Lax by default”.
+# about:home should be kept in English, as it refers to the the URI for
+# the internal default home page.
+experimental-features-abouthome-startup-cache =
+    .label = about:home startup cache
+experimental-features-abouthome-startup-cache-description = Storfa ar gyfer y ddogfen gychwynnol about:home sy'n cael ei llwytho yn ragosodedig wrth gychwyn. Pwrpas y storfa yw gwella perfformiad cychwyn.
+experimental-features-print-preview-tab-modal =
+    .label = Ailgynllunio'r Rhagolwg Argraffu
+experimental-features-print-preview-tab-modal-description = Mae rhagolwg argraffu wedi'i ailgynllunio ac yn cynnig rhagolwg argraffu ar y macOS. Gall hyn o bosibl gyflwyno toriadau ac nid yw'n cynnwys yr holl osodiadau sy'n gysylltiedig ag argraffu. I gael mynediad at yr holl osodiadau sy'n gysylltiedig ag argraffu, dewiswch "Argraffu gan ddefnyddio deialog y system..." o fewn y panel Argraffu.
+# The title of the experiment should be kept in English as it may be referenced
+# by various online articles and is technical in nature.
+experimental-features-cookie-samesite-schemeful =
+    .label = Cookies: Schemeful SameSite
+experimental-features-cookie-samesite-schemeful-description = Trin cwcis o'r un parth, ond gyda gwahanol gynlluniau (e.e. http://example.com a https://example.com) fel traws-gwefan yn lle'r un wefan. Yn gwella diogelwch, ond o bosibl yn cyflwyno toriadau.
+# "Service Worker" is an API name and is usually not translated.
+experimental-features-devtools-serviceworker-debugger-support =
+    .label = Developer Tools: Service Worker debugging
+# "Service Worker" is an API name and is usually not translated.
+experimental-features-devtools-serviceworker-debugger-support-description = Yn galluogi cefnogaeth arbrofol i Weithwyr Gwasanaeth yn y panel Dadfygiwr. Efallai y bydd y nodwedd hon yn arafu'r Offer Datblygwr ac yn cynyddu'r defnydd o gof.
+# WebRTC global mute toggle controls
+experimental-features-webrtc-global-mute-toggles =
+    .label = Toglau Tewi WebRTC Cyffredinol
+experimental-features-webrtc-global-mute-toggles-description = Ychwanegwch ffyrdd o reoli dangosydd rhannu WebRTC i gyd sy'n caniatáu i ddefnyddwyr dewi eu llif meicroffon a chamera.
+# JS JIT Warp project
+experimental-features-js-warp =
+    .label = JavaScript JIT: Warp
+experimental-features-js-warp-description = Galluogi Warp, project i wella perfformiad JavaScript a defnydd o'r cof.
+# Fission is the name of the feature and should not be translated.
+experimental-features-fission =
+    .label = Fission (Ynysu Gwefan)
+experimental-features-fission-description = Mae Fission (ynysu gwefan) yn nodwedd arbrofol yn { -brand-short-name } er mwyn darparu haen ychwanegol o ddiogelwch yn erbyn bygiau diogelwch. Trwy ynysu pob gwefan i broses ar wahân, mae Fission yn ei gwneud hi'n anoddach i wefannau maleisus gael mynediad at wybodaeth o dudalennau eraill rydych chi'n ymweld â nhw. Mae hwn yn newid pensaernïol mawr yn { -brand-short-name } ac rydym yn gwerthfawrogi eich bod yn profi ac yn adrodd am unrhyw faterion y gallech ddod ar eu traws. Am fwy o fanylion, darllenwch <a data-l10n-name="wiki">y wiki</a>.
+# Support for having multiple Picture-in-Picture windows open simultaneously
+experimental-features-multi-pip =
+    .label = Cefnogaeth Llun-mewn-Llun Lluosog
+experimental-features-multi-pip-description = Cefnogaeth arbrofol i ganiatáu i nifer o ffenestri Llun-mewn-Llun fod ar agor ar yr un pryd.
+experimental-features-http3 =
+    .label = Protocol HTTP/3
+experimental-features-http3-description = Cefnogaeth arbrofol i brotocol HTTP/3.
+# Search during IME
+experimental-features-ime-search =
+    .label = Bar Cyfeiriadau: dangos canlyniadau wrth ddefnyddio'r IME
+experimental-features-ime-search-description = Offeryn yw IME (Golygydd Dull Mewnbwn) sy'n eich galluogi i nodi symbolau cymhleth, fel y rhai sy'n cael eu ddefnyddio mewn ieithoedd ysgrifenedig yn Nwyrain Asia neu India, gan ddefnyddio bysellfwrdd safonol. Bydd galluogi'r arbrawf hwn yn cadw'r panel bar cyfeiriadau ar agor, dangos canlyniadau chwilio ac awgrymiadau, tra'n defnyddio IME i fewnbynnu testun. Sylwch y gallai'r IME ddangos panel sy'n ymdrin â chanlyniadau'r bar cyfeiriad, felly mae'r dewis hwn yn cael ei awgrymu ar gyfer IME sydd ddim yn defnyddio'r math hwn o banel.
diff --git a/l10n-cy/toolkit/toolkit/global/createProfileWizard.ftl b/l10n-cy/toolkit/toolkit/global/createProfileWizard.ftl
new file mode 100644
index 0000000000..36e13010b0
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/createProfileWizard.ftl
@@ -0,0 +1,53 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+create-profile-window =
+    .title = Creu Proffil Dewin
+    .style = width: 45em; height: 32em;
+
+## First wizard page
+
+create-profile-first-page-header =
+    { PLATFORM() ->
+        [macos] Cyflwyniad
+       *[other] Croeso i { create-profile-window.title }
+    }
+
+profile-creation-explanation-1 = Mae { -brand-short-name } yn storio gwybodaeth am eich gosodiadau a'ch dewisiadau yn eich proffil personol.
+
+profile-creation-explanation-2 = Os ydych yn rhannu'r copi o { -brand-short-name } gyda defnyddwyr eraill, mae modd defnyddio proffiliau i gadw gwybodaeth eich gilydd ar wahân. I wneud hyn, dylai pob defnyddiwr greu ei broffil ei hun.
+
+profile-creation-explanation-3 = Os mai chi yw'r unig berson sy'n defnyddio'r copi o { -brand-short-name }, rhaid i chi gael o leiaf un proffil. Os hoffech chi mae modd creu proffiliau niferus er mwyn cadw gosodiadau a dewisiadau i chi eich hun. Er enghraifft, efallai yr hoffech chi gael proffil gwahanol ar gyfer defnydd busnes neu bersonol.
+
+profile-creation-explanation-4 =
+    { PLATFORM() ->
+        [macos] I gychwyn creu eich proffil, cliciwch Ymlaen.
+       *[other] I gychwyn creu eich proffil, cliciwch Nesaf.
+    }
+
+## Second wizard page
+
+create-profile-last-page-header =
+    { PLATFORM() ->
+        [macos] Diweddglo
+       *[other] Cwblhau { create-profile-window.title }
+    }
+
+profile-creation-intro = Os ydych yn creu nifer o broffiliau mae modd eu gwahaniaethu wrth enw'r proffil. Mae modd defnyddio'r enw sy'n cael ei ddarparu yma neu enw eich hun.
+
+profile-prompt = Rhowch enw proffil newydd:
+    .accesskey = e
+
+profile-default-name =
+    .value = Defnyddiwr Rhagosodedig
+
+profile-directory-explanation = Bydd eich gosodiadau defnyddiwr, dewisiadau a data arall sy'n perthyn i ddefnyddiwr yn cael ei gadw yn:
+
+create-profile-choose-folder =
+    .label = Dewis Ffolder…
+    .accesskey = D
+
+create-profile-use-default =
+    .label = Defnyddio'r Ffolder Rhagosodedig
+    .accesskey = R
diff --git a/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl b/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl
new file mode 100644
index 0000000000..0a6266044c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl
@@ -0,0 +1,69 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Please keep the emphasis around the hostname and scheme (ie the
+# `<strong>` HTML tags). Please also keep the hostname as close to the start
+# of the sentence as your language's grammar allows.
+#
+# Variables:
+#  $host - the hostname that is initiating the request
+#  $scheme - the type of link that's being opened.
+handler-dialog-host = Mae <strong>{ $host }</strong> eisiau agor dolen <strong>{ $scheme }</strong>.
+
+## Permission Dialog
+## Variables:
+##  $host - the hostname that is initiating the request
+##  $scheme - the type of link that's being opened.
+##  $appName - Name of the application that will be opened.
+
+permission-dialog-description = Caniatáu i'r wefan hon agor y ddolen { $scheme }?
+permission-dialog-description-file = Caniatáu i'r ffeil hon agor y ddolen { $scheme }?
+permission-dialog-description-host = Caniatáu i { $host } agor y ddolen { $scheme }?
+permission-dialog-description-app = Caniatáu i'r wefan hon agor y ddolen { $scheme } gyda { $appName }?
+permission-dialog-description-host-app = Caniatáu i { $host } agor y ddolen { $scheme } gyda { $appName }?
+permission-dialog-description-file-app = Caniatáu i'r ffeil hon agor y ddolen { $scheme } gyda { $appName }?
+
+## Please keep the emphasis around the hostname and scheme (ie the
+## `<strong>` HTML tags). Please also keep the hostname as close to the start
+## of the sentence as your language's grammar allows.
+
+permission-dialog-remember = Caniatáu i <strong>{ $host }</strong> agor dolenni <strong>{ $scheme }</strong> bob tro
+permission-dialog-remember-file = Gadewch i'r ffeil hon agor dolenni <strong>{ $scheme }</strong> bob tro
+
+##
+
+permission-dialog-btn-open-link =
+    .label = Agor Dolen
+    .accessKey = A
+permission-dialog-btn-choose-app =
+    .label = Dewis Rhaglen
+    .accessKey = R
+permission-dialog-unset-description = Bydd angen i chi ddewis rhaglen.
+permission-dialog-set-change-app-link = Dewiswch raglen arall.
+
+## Chooser dialog
+## Variables:
+##  $scheme - the type of link that's being opened.
+
+chooser-window =
+    .title = Dewis Rhaglen
+    .style = min-width: 26em; min-height: 26em;
+chooser-dialog =
+    .buttonlabelaccept = Agor Dolen
+    .buttonaccesskeyaccept = A
+chooser-dialog-description = Dewiswch raglen i agor y ddolen { $scheme }.
+# Please keep the emphasis around the scheme (ie the `<strong>` HTML tags).
+chooser-dialog-remember = Defnyddiwch y rhaglen hon i agor dolenni <strong>{ $scheme }</strong> bob tro
+chooser-dialog-remember-extra =
+    { PLATFORM() ->
+        [windows] Mae modd newid hwn yn newisiadau { -brand-short-name }.
+       *[other] Mae modd newid hwn yn newisiadau { -brand-short-name }.
+    }
+choose-other-app-description = Dewis Rhaglen arall
+choose-app-btn =
+    .label = Dewis…
+    .accessKey = D
+choose-other-app-window-title = Rhaglen Arall…
+# Displayed under the name of a protocol handler in the Launch Application dialog.
+choose-dialog-privatebrowsing-disabled = Analluogwyd mewn Ffenestri Preifat
diff --git a/l10n-cy/toolkit/toolkit/global/processTypes.ftl b/l10n-cy/toolkit/toolkit/global/processTypes.ftl
new file mode 100644
index 0000000000..a553d09c4f
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/processTypes.ftl
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+process-type-web = Cynnwys Gwe
+
+# process used to run privileged about pages,
+# such as about:home
+process-type-privilegedabout = About Breintiedig
+
+# process used to run privileged mozilla pages,
+# such as accounts.firefox.com
+process-type-privilegedmozilla = Cynnwys Mozilla Breintiedig
+
+process-type-extension = Estyniad
+
+# process used to open file:// URLs
+process-type-file = Ffeil Leol
+
+# process used to isolate webpages that requested special
+# permission to allocate large amounts of memory
+process-type-weblargeallocation = Dyraniad Mawr
+
+# process used to isolate a webpage from other web pages
+# to improve security
+process-type-webisolated = Cynnwys Gwe Ynysig
+
+# process used to communicate with the GPU for
+# graphics acceleration
+process-type-gpu = GPU
+
+# process used to perform network operations
+process-type-socket = Soced
+
+# process preallocated; may change to other types
+process-type-prealloc = Rhagddyranwyd
diff --git a/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl b/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl
new file mode 100644
index 0000000000..53c4d418c4
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl
@@ -0,0 +1,20 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+profiledowngrade-window =
+    .title = Rydych chi wedi cychwyn fersiwn hŷn o { -brand-product-name }
+    .style = width: 490px;
+
+profiledowngrade-window-create =
+    .label = Creu Proffil Newydd
+
+profiledowngrade-sync = Mae defnyddio fersiwn hŷn o { -brand-product-name } yn gallu llygru nodiadau llyfr a hanes pori sydd eisoes wedi'u cadw i broffil { -brand-product-name } presennol. Er mwyn diogelu'ch gwybodaeth, crëwch broffil newydd ar gyfer gosodiad hwn o { -brand-short-name }. Gallwch fewngofnodi gyda { -fxaccount-brand-name } i gydweddu eich nodau tudalen a'ch hanes pori rhwng proffiliau.
+profiledowngrade-nosync = Mae defnyddio fersiwn hŷn o { -brand-product-name } yn gallu llygru nodau tudalen a hanes pori sydd eisoes wedi'u cadw i broffil { -brand-product-name } presennol. Er mwyn diogelu'ch gwybodaeth, crëwch broffil newydd ar gyfer gosod { -brand-short-name }.
+
+profiledowngrade-quit =
+    .label =
+        { PLATFORM() ->
+            [windows] Gadael
+           *[other] Gadael
+        }
diff --git a/l10n-cy/toolkit/toolkit/global/profileSelection.ftl b/l10n-cy/toolkit/toolkit/global/profileSelection.ftl
new file mode 100644
index 0000000000..5616e2655b
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/profileSelection.ftl
@@ -0,0 +1,36 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+profile-selection-window =
+    .title = { -brand-short-name } - Dewiswch Broffil Defnyddiwr
+
+profile-selection-button-accept =
+    .label = Cychwyn { -brand-short-name }
+
+profile-selection-button-cancel =
+    .label = Gadael
+
+profile-selection-new-button =
+    .label = Creu Proffil…
+    .accesskey = C
+
+profile-selection-rename-button =
+    .label = Ailenwi Profil…
+    .accesskey = r
+
+profile-selection-delete-button =
+    .label = Dileu Proffil…
+    .accesskey = D
+
+## Messages used in the profile manager
+
+profile-manager-description = Mae { -brand-short-name } yn storio gwybodaeth am eich gosodiadau, dewisiadau ac eitemau defnyddiwr arall yn eich proffil defnyddiwr.
+
+profile-manager-work-offline =
+    .label = Gweithio All-lein
+    .accesskey = o
+
+profile-manager-use-selected =
+    .label = Defnyddio'r proffil penodol heb ofyn wrth gychwyn
+    .accesskey = p
diff --git a/l10n-cy/toolkit/toolkit/global/resetProfile.ftl b/l10n-cy/toolkit/toolkit/global/resetProfile.ftl
new file mode 100644
index 0000000000..5cbc72b5a9
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/resetProfile.ftl
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+refresh-profile-dialog =
+    .title = Adnewyddu { -brand-short-name }
+refresh-profile-dialog-button =
+    .label = Adnewyddu { -brand-short-name }
+refresh-profile-description = Cychwyn o'r newydd i ddatrys problemau ac adfer perfformiad.
+refresh-profile-description-details = Bydd hyn yn:
+refresh-profile-remove = Tynnu eich ychwanegion a'ch cyfaddasiadau
+refresh-profile-restore = Adfer eich gosodiadau pori i'w rhagosodiad
+refresh-profile = Rhoi bywyd newydd i { -brand-short-name }
+refresh-profile-button = Adnewyddu { -brand-short-name }…
diff --git a/l10n-cy/toolkit/toolkit/global/textActions.ftl b/l10n-cy/toolkit/toolkit/global/textActions.ftl
new file mode 100644
index 0000000000..3d7e4d19da
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/textActions.ftl
@@ -0,0 +1,49 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+text-action-undo =
+    .label = Dadwneud
+    .accesskey = w
+
+text-action-undo-shortcut =
+    .key = Z
+
+text-action-redo =
+    .label = Ailwneud
+    .accesskey = A
+
+text-action-redo-shortcut =
+    .key = Y
+
+text-action-cut =
+    .label = Torri
+    .accesskey = T
+
+text-action-cut-shortcut =
+    .key = X
+
+text-action-copy =
+    .label = Copïo
+    .accesskey = C
+
+text-action-copy-shortcut =
+    .key = C
+
+text-action-paste =
+    .label = Gludo
+    .accesskey = G
+
+text-action-paste-shortcut =
+    .key = V
+
+text-action-delete =
+    .label = Dileu
+    .accesskey = i
+
+text-action-select-all =
+    .label = Dewis Popeth
+    .accesskey = P
+
+text-action-select-all-shortcut =
+    .key = A
diff --git a/l10n-cy/toolkit/toolkit/global/unknownContentType.ftl b/l10n-cy/toolkit/toolkit/global/unknownContentType.ftl
new file mode 100644
index 0000000000..50d6dd99df
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/unknownContentType.ftl
@@ -0,0 +1,13 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+unknowncontenttype-handleinternally =
+    .label = Agor gyda { -brand-short-name }
+    .accesskey = A
+unknowncontenttype-settingschange =
+    .value =
+        { PLATFORM() ->
+            [windows] Mae modd newid gosodiadau yn Opsiynau { -brand-short-name }.
+           *[other] Mae modd newid gosodiadau yn Dewisiadau { -brand-short-name }.
+        }
diff --git a/l10n-cy/toolkit/toolkit/global/videocontrols.ftl b/l10n-cy/toolkit/toolkit/global/videocontrols.ftl
new file mode 100644
index 0000000000..79aa378803
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/videocontrols.ftl
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+videocontrols-scrubber =
+    .aria-label = Safle
+# This label is used by screenreaders and other assistive technology to indicate
+# to users how much of the video has been loaded from the network. It will be
+# followed by the percentage of the video that has loaded (e.g. "Loading: 13%").
+videocontrols-buffer-bar-label = Llwytho:
+videocontrols-volume-control =
+    .aria-label = Lefel y sain
+videocontrols-closed-caption-button =
+    .aria-label = Capsiynau Caeedig
diff --git a/l10n-cy/toolkit/toolkit/global/wizard.ftl b/l10n-cy/toolkit/toolkit/global/wizard.ftl
new file mode 100644
index 0000000000..3f50113b90
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/wizard.ftl
@@ -0,0 +1,37 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+wizard-macos-button-back =
+    .label = Mynd Nôl
+    .accesskey = N
+wizard-linux-button-back =
+    .label = Nôl
+    .accesskey = N
+wizard-win-button-back =
+    .label = < Nôl
+    .accesskey = l
+
+wizard-macos-button-next =
+    .label = Ymlaen
+    .accesskey = Y
+wizard-linux-button-next =
+    .label = Nesaf
+    .accesskey = e
+wizard-win-button-next =
+    .label = Nesaf >
+    .accesskey = e
+
+wizard-macos-button-finish =
+    .label = Gorffen
+wizard-linux-button-finish =
+    .label = Gorffen
+wizard-win-button-finish =
+    .label = Gorffen
+
+wizard-macos-button-cancel =
+    .label = Diddymu
+wizard-linux-button-cancel =
+    .label = Diddymu
+wizard-win-button-cancel =
+    .label = Diddymu
diff --git a/l10n-cy/toolkit/toolkit/intl/languageNames.ftl b/l10n-cy/toolkit/toolkit/intl/languageNames.ftl
new file mode 100644
index 0000000000..f21c385cf2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/intl/languageNames.ftl
@@ -0,0 +1,212 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+language-name-aa = Afar
+language-name-ab = Abcasaidd
+language-name-ach = Acholi
+language-name-ae = Avestan
+language-name-af = Affricaneg
+language-name-ak = Akan
+language-name-am = Amhareg
+language-name-an = Aragoneg
+language-name-ar = Arabeg
+language-name-as = Assameje
+language-name-ast = Asturieg
+language-name-av = Avareg
+language-name-ay = Aymara
+language-name-az = Azereg
+language-name-ba = Bashkir
+language-name-be = Belorwseg
+language-name-bg = Bwlgareg
+language-name-bh = Bihari
+language-name-bi = Bislameg
+language-name-bm = Bambara
+language-name-bn = Bengaleg
+language-name-bo = Tibet
+language-name-br = Llydaweg
+language-name-bs = Bosniaeg
+language-name-ca = Catalaneg
+language-name-cak = Kaqchikel
+language-name-ce = Chechen
+language-name-ch = Chamorro
+language-name-co = Corseg
+language-name-cr = Cree
+language-name-crh = Tatar Crimea
+language-name-cs = Tsieceg
+language-name-csb = Kashubian
+language-name-cu = Slafeg Eglwysig
+language-name-cv = Chuvash
+language-name-cy = Cymraeg
+language-name-da = Daeneg
+language-name-de = Almaeneg
+language-name-dsb = Sorbieg Isaf
+language-name-dv = Divehi
+language-name-dz = Dzongkha
+language-name-ee = Ewe
+language-name-el = Groeg
+language-name-en = Saesneg
+language-name-eo = Esperanto
+language-name-es = Sbaeneg
+language-name-et = Estoneg
+language-name-eu = Basgeg
+language-name-fa = Persieg
+language-name-ff = Fulah
+language-name-fi = Ffineg
+language-name-fj = Fijieg
+language-name-fo = Ffaroeg
+language-name-fr = Ffrangeg
+language-name-fur = Ffriulieg
+language-name-fy = Frisieg
+language-name-ga = Gwyddeleg
+language-name-gd = Gaeleg yr Alban
+language-name-gl = Galiseg
+language-name-gn = Gwarani
+language-name-gu = Gwjarati
+language-name-gv = Manaweg
+language-name-ha = Hawsa
+language-name-haw = Hawaieg
+language-name-he = Hebraeg
+language-name-hi = Hindi
+language-name-hil = Hiligaynon
+language-name-ho = Hiri Motu
+language-name-hr = Croateg
+language-name-hsb = Sorbieg Uchaf
+language-name-ht = Haiteg
+language-name-hu = Hwngareg
+language-name-hy = Armeneg
+language-name-hz = Herero
+language-name-ia = Interlingua
+language-name-id = Indonesieg
+language-name-ie = Interlingue
+language-name-ig = Igbo
+language-name-ii = Sichuan Yi
+language-name-ik = Inupiaq
+language-name-io = Ido
+language-name-is = Islandeg
+language-name-it = Eidaleg
+language-name-iu = Inuktitut
+language-name-ja = Siapanaëeg
+language-name-jv = Java
+language-name-ka = Georgeg
+language-name-kab = Kabyle
+language-name-kg = Kongo
+language-name-ki = Kikuyu
+language-name-kj = Kuanyama
+language-name-kk = Kazakh
+language-name-kl = Esgimoeg
+language-name-km = Khmer
+language-name-kn = Canareg
+language-name-ko = Coreeg
+language-name-kok = Konkani
+language-name-kr = Kanuri
+language-name-ks = Kashmir
+language-name-ku = Kwrdeg
+language-name-kv = Komi
+language-name-kw = Cernyweg
+language-name-ky = Kighiz
+language-name-la = Lladin
+language-name-lb = Luxembourgeg
+language-name-lg = Ganda
+language-name-li = Limburgeg
+language-name-lij = Ligurieg
+language-name-ln = Lingala
+language-name-lo = Lao
+language-name-lt = Lithwaneg
+language-name-ltg = Latgalieg
+language-name-lu = Luba-Katanga
+language-name-lv = Latfieg
+language-name-mai = Maithili
+language-name-meh = Tlaxiaco Mixtec y De Orllewin
+language-name-mg = Malagasy
+language-name-mh = Marshalleg
+language-name-mi = Maori
+language-name-mix = Mixtepec Mixtec
+language-name-mk = Macedoneg
+language-name-ml = Malaialam
+language-name-mn = Mongoleg
+language-name-mr = Marathi
+language-name-ms = Malaisieg
+language-name-mt = Malteg
+language-name-my = Byrmaneg
+language-name-na = Nauru
+language-name-nb = Norwyeg Bokmaal
+language-name-nd = Ndebele Gogleddol
+language-name-ne = Nepalieg
+language-name-ng = Ndonga
+language-name-nl = Iseldireg
+language-name-nn = Norwyeg Nynorsk
+language-name-no = Norwyeg
+language-name-nr = Ndebele Deheuol
+language-name-nso = Sotho Gogleddol
+language-name-nv = Navajo
+language-name-ny = Chichewa
+language-name-oc = Occitaneg
+language-name-oj = Ojibwa
+language-name-om = Oromo
+language-name-or = Odia
+language-name-os = Ossetian
+language-name-pa = Punjabeg
+language-name-pi = Pali
+language-name-pl = Pwyleg
+language-name-ps = Pashto
+language-name-pt = Portiwgaleg
+language-name-qu = Quechua
+language-name-rm = Rheto-Romaneg
+language-name-rn = Kirundi
+language-name-ro = Rwmaneg
+language-name-ru = Rwseg
+language-name-rw = Kinyarwanda
+language-name-sa = Sansgrit
+language-name-sc = Sardinieg
+language-name-sd = Sindhi
+language-name-se = Sami Gogleddol
+language-name-sg = Sango
+language-name-si = Singhaleg
+language-name-sk = Slofacieg
+language-name-sl = Slofeneg
+language-name-sm = Samoeg
+language-name-sn = Shona
+language-name-so = Somali
+language-name-son = Songhay
+language-name-sq = Albaneg
+language-name-sr = Serbeg
+language-name-ss = Siswati
+language-name-st = Sotho Deheuol
+language-name-su = Sundaneg
+language-name-sv = Swedeg
+language-name-sw = Swahili
+language-name-ta = Tamileg
+language-name-te = Telugu
+language-name-tg = Tajik
+language-name-th = Tai
+language-name-ti = Tigrinya
+language-name-tig = Tigre
+language-name-tk = Turkmen
+language-name-tl = Tagalog
+language-name-tlh = Klingon
+language-name-tn = Tswana
+language-name-to = Tonga
+language-name-tr = Twrceg
+language-name-trs = Triqui
+language-name-ts = Tsonga
+language-name-tt = Tatar
+language-name-tw = Twi
+language-name-ty = Tahiteg
+language-name-ug = Uighur
+language-name-uk = Wcraneg
+language-name-ur = Wrdw
+language-name-uz = Wsbeceg
+language-name-ve = Venda
+language-name-vi = Fietnameg
+language-name-vo = Volapük
+language-name-wa = Walloon
+language-name-wen = Sorbeg
+language-name-wo = Wolof
+language-name-xh = Xhosa
+language-name-yi = Iddeweg
+language-name-yo = Yoruba
+language-name-za = Zhuang
+language-name-zam = Miahuatlán Zapotec
+language-name-zh = Tsieinëeg
+language-name-zu = Zwlweg
diff --git a/l10n-cy/toolkit/toolkit/intl/regionNames.ftl b/l10n-cy/toolkit/toolkit/intl/regionNames.ftl
new file mode 100644
index 0000000000..149aa85aff
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/intl/regionNames.ftl
@@ -0,0 +1,280 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### Notice: If you're updating this list, you should also
+###         update the list in mozIntl.js.
+
+region-name-ad = Andorra
+region-name-ae = United Arab Emirates
+region-name-af = Afghanistan
+region-name-ag = Antigua a Barbuda
+region-name-ai = Anguilla
+region-name-al = Albania
+region-name-am = Armenia
+region-name-ao = Angola
+region-name-aq = Antarctica
+region-name-ar = Ariannin
+region-name-as = Samoa Americanaidd
+region-name-at = Awstria
+region-name-au = Awstralia
+region-name-aw = Aruba
+region-name-az = Azerbaijan
+region-name-ba = Bosnia a Herzegovina
+region-name-bb = Barbados
+region-name-bd = Bangladesh
+region-name-be = Gwlad Belg
+region-name-bf = Burkina Faso
+region-name-bg = Bwlgaria
+region-name-bh = Bahrain
+region-name-bi = Burundi
+region-name-bj = Benin
+region-name-bl = Saint Barthélemy
+region-name-bm = Bermuda
+region-name-bn = Brunei
+region-name-bo = Bolivia
+region-name-bq = Bonaire, Sint Eustatius, a Saba
+region-name-br = Brasil
+region-name-bs = Bahamas
+region-name-bt = Bhutan
+region-name-bv = Ynys Bouvet
+region-name-bw = Botswana
+region-name-by = Belarus
+region-name-bz = Belize
+region-name-ca = Canada
+region-name-cc = Ynysoedd Cocos (Keeling)
+region-name-cd = Congo (Kinshasa)
+region-name-cf = Gweriniaeth Affricanaidd Congo
+region-name-cg = Congo (Brazzaville)
+region-name-ch = Y Swistir
+region-name-ci = Côte d’Ivoire
+region-name-ck = Ynysoedd Cook
+region-name-cl = Chile
+region-name-cm = Cameroon
+region-name-cn = Tsieina
+region-name-co = Colombia
+region-name-cp = Ynys Clipperton
+region-name-cr = Costa Rica
+region-name-cu = Ciwba
+region-name-cv = Cape Verde
+region-name-cw = Curaçao
+region-name-cx = Ynys Christmas
+region-name-cy = Cyprus
+region-name-cz = Gweriniaeth Tsiec
+region-name-de = Yr Almaen
+region-name-dg = Diego Garcia
+region-name-dj = Djibouti
+region-name-dk = Denmarc
+region-name-dm = Dominica
+region-name-do = Gweriniaeth Dominica
+region-name-dz = Algeria
+region-name-ec = Ecuador
+region-name-ee = Estonia
+region-name-eg = Yr Aifft
+region-name-eh = Gorllenwin Sahara
+region-name-er = Eritrea
+region-name-es = Sbaen
+region-name-et = Ethiopia
+region-name-fi = Ffindir
+region-name-fj = Ffiji
+region-name-fk = Ynysoedd Malfinas (Falkland)
+region-name-fm = Micronesia, Federated States of
+region-name-fo = Ynysoedd Ffaroe
+region-name-fr = Ffrainc
+region-name-ga = Gabon
+region-name-gb = Y Deyrnas Unedig
+region-name-gd = Grenada
+region-name-ge = Georgia
+region-name-gf = Guiana Ffrengig
+region-name-gg = Guernsey
+region-name-gh = Ghana
+region-name-gi = Gibraltar
+region-name-gl = Greenland
+region-name-gm = Gambia
+region-name-gn = Guinea
+region-name-gp = Guadeloupe
+region-name-gq = Guinea Cyhydeddol
+region-name-gr = Groeg
+region-name-gs = De Georgia ac Ynysoedd De Sandwich
+region-name-gt = Guatemala
+region-name-gu = Guam
+region-name-gw = Guinea-Bissau
+region-name-gy = Guyana
+region-name-hk = Hong Kong
+region-name-hm = Ynys Heard ac Ynys McDonald
+region-name-hn = Honduras
+region-name-hr = Croatia
+region-name-ht = Haiti
+region-name-hu = Hwngari
+region-name-id = Indonesia
+region-name-ie = Iwerddon
+region-name-il = Israel
+region-name-im = Ynys Manaw
+region-name-in = India
+region-name-io = Tiriogaeth Cefnfor Indiaidd Prydain
+region-name-iq = Irac
+region-name-ir = Iran
+region-name-is = Ynys yr Iâ
+region-name-it = Yr Eidal
+region-name-je = Jersey
+region-name-jm = Jamaica
+region-name-jo = Yr Iorddonen
+region-name-jp = Siapan
+region-name-ke = Kenya
+region-name-kg = Kyrgyzstan
+region-name-kh = Cambodia
+region-name-ki = Kiribati
+region-name-km = Comoros
+region-name-kn = Saint Kitts a Nevis
+region-name-kp = Corea, Gogledd
+region-name-kr = Corea, De
+region-name-kw = Kuwait
+region-name-ky = Ynysoedd Cayman
+region-name-kz = Kazakhstan
+region-name-la = Laos
+region-name-lb = Libanus
+region-name-lc = Saint Lucia
+region-name-li = Luxembourg
+region-name-lk = Sri Lanka
+region-name-lr = Liberia
+region-name-ls = Lesotho
+region-name-lt = Lithiwania
+region-name-lu = Liechtenstein
+region-name-lv = Latfia
+region-name-ly = Libya
+region-name-ma = Morocco
+region-name-mc = Monaco
+region-name-md = Moldova
+region-name-me = Montenegro
+region-name-mf = Saint Martin
+region-name-mg = Madagascar
+region-name-mh = Ynysoedd Marshall
+region-name-mk = Macedonia
+region-name-ml = Mali
+region-name-mm = Burma
+region-name-mn = Mongolia
+region-name-mo = Macau
+region-name-mp = Ynysoedd Gogledd Mariana
+region-name-mq = Martinique
+region-name-mr = Mauritania
+region-name-ms = Montserrat
+region-name-mt = Malta
+region-name-mu = Mauritius
+region-name-mv = Maldives
+region-name-mw = Malawi
+region-name-mx = Mecsico
+region-name-my = Malaysia
+region-name-mz = Mozambique
+region-name-na = Namibia
+region-name-nc = Caledonia Newydd
+region-name-ne = Niger
+region-name-nf = Ynys Norfolk
+region-name-ng = Nigeria
+region-name-ni = Nicaragua
+region-name-nl = Yr Iseldiroedd
+region-name-no = Norwy
+region-name-np = Nepal
+region-name-nr = Nauru
+region-name-nu = Niue
+region-name-nz = Seland Newydd
+region-name-om = Oman
+region-name-pa = Panama
+region-name-pe = Periw
+region-name-pf = Polynesia Ffrengig
+region-name-pg = Papua Guinea Newydd
+region-name-ph = Philippines
+region-name-pk = Pacistan
+region-name-pl = Gwlad Pwyl
+region-name-pm = Saint Pierre a Miquelon
+region-name-pn = Ynysoedd Pitcairn
+region-name-pr = Puerto Rico
+region-name-pt = Portiwgal
+region-name-pw = Palau
+region-name-py = Paraguay
+region-name-qa = Qatar
+region-name-qm = Ynysoedd Midway
+region-name-qs = Bassas da India
+region-name-qu = Ynys Juan de Nova
+region-name-qw = Ynys Wake
+region-name-qx = Ynysoedd Glorioso
+region-name-qz = Akrotiri
+region-name-re = Reunion
+region-name-ro = Rwmania
+region-name-rs = Serbia
+region-name-ru = Rwsia
+region-name-rw = Rwanda
+region-name-sa = Saudi Arabia
+region-name-sb = Ynysoedd Solomon
+region-name-sc = Seychelles
+region-name-sd = Swdan
+region-name-se = Sweden
+region-name-sg = Singapore
+region-name-sh = Saint Helena, Ascension, a Tristan da Cunha
+region-name-si = Slofenia
+region-name-sk = Slofacia
+region-name-sl = Sierra Leone
+region-name-sm = San Marino
+region-name-sn = Senegal
+region-name-so = Somalia
+region-name-sr = Suriname
+region-name-ss = De Sudan
+region-name-st = Sao Tome a Principe
+region-name-sv = El Salvador
+region-name-sx = Sint Maarten
+region-name-sy = Syria
+region-name-sz = Swaziland
+region-name-tc = Ynysoedd Turks a Caicos
+region-name-td = Chad
+region-name-tf = Tiriogaethau De ac Antartic Ffrainc
+region-name-tg = Togo
+region-name-th = Thailand
+region-name-tj = Tajikistan
+region-name-tk = Tokelau
+region-name-tl = Timor-Leste
+region-name-tm = Turkmenistan
+region-name-tn = Tunisia
+region-name-to = Tonga
+region-name-tr = Twrci
+region-name-tt = Trinidad a Tobago
+region-name-tv = Tuvalu
+region-name-tw = Taiwan
+region-name-tz = Tanzania
+region-name-ua = Wcrain
+region-name-ug = Uganda
+region-name-us = Yr Unol Daleithiau
+region-name-uy = Uruguay
+region-name-uz = Uzbekistan
+region-name-va = Dinas y Fatican
+region-name-vc = Saint Vincent a'r Grenadinau
+region-name-ve = Venezuela
+region-name-vg = Ynysoedd Virgin Prydain
+region-name-vi = Ynysoedd Virgin, UDA.
+region-name-vn = Fietnam
+region-name-vu = Vanuatu
+region-name-wf = Wallis a Futuna
+region-name-ws = Samoa
+region-name-xa = Ynysoedd Ashmore a Cartier
+region-name-xb = Ynys Baker
+region-name-xc = Ynysoedd y Môr Cwrel
+region-name-xd = Dhekelia
+region-name-xe = Ynys Europa
+region-name-xg = Llain Gaza
+region-name-xh = Ynys Howland
+region-name-xj = Jan Mayen
+region-name-xk = Kosovo
+region-name-xl = Atol Palmyra
+region-name-xm = Riff Kingman
+region-name-xp = Ynysoedd Parasel
+region-name-xq = Ynys Jarvis
+region-name-xr = Svalbard
+region-name-xs = Ynysoedd Spratly
+region-name-xt = Ynys Tromelin
+region-name-xu = Atol Johnston
+region-name-xv = Ynys Navassa
+region-name-xw = Ardal Gorllewin
+region-name-ye = Yemen
+region-name-yt = Mayotte
+region-name-za = De Affrica
+region-name-zm = Zambia
+region-name-zw = Zimbabwe
diff --git a/l10n-cy/toolkit/toolkit/main-window/autocomplete.ftl b/l10n-cy/toolkit/toolkit/main-window/autocomplete.ftl
new file mode 100644
index 0000000000..3ab63f5cd2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/main-window/autocomplete.ftl
@@ -0,0 +1,32 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Import Logins Autocomplete
+
+# Variables:
+#   $browser (String) - Browser name to import logins from.
+#   $host (String) - Host name of the current site.
+autocomplete-import-logins =
+    <div data-l10n-name="line1">Mewnforio eich data o { $browser }</div>
+    <div data-l10n-name="line2">ar gyfer { $host } a gwefannau eraill</div>
+autocomplete-import-logins-info =
+    .tooltiptext = Dysgu rhagor
+
+## Variables:
+##   $host (String) - Host name of the current site.
+
+autocomplete-import-logins-chrome =
+    <div data-l10n-name="line1">Mewnforio eich data o o Google Chrome </div>
+    <div data-l10n-name="line2">ar gyfer { $host } a gwefannau eraill</div>
+autocomplete-import-logins-chromium =
+    <div data-l10n-name="line1">Mewnforio eich mewngofnod o Chromium</div>
+    <div data-l10n-name="line2">ar gyfer { $host } a gwefannau eraill</div>
+autocomplete-import-logins-chromium-edge =
+    <div data-l10n-name="line1">Mewnforio eich mewngofnod o Microsoft Edge</div>
+    <div data-l10n-name="line2">ar gyfer { $host } a gwefannau eraill</div>
+
+##
+
+autocomplete-import-learn-more = Dysgu rhagor
diff --git a/l10n-cy/toolkit/toolkit/main-window/findbar.ftl b/l10n-cy/toolkit/toolkit/main-window/findbar.ftl
new file mode 100644
index 0000000000..66190490e1
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/main-window/findbar.ftl
@@ -0,0 +1,38 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+### This file contains the entities needed to use the Find Bar.
+
+findbar-next =
+    .tooltiptext = Canfod enghraifft nesaf yr ymadrodd
+findbar-previous =
+    .tooltiptext = Canfod enghraifft flaenorol o'r ymadrodd
+
+findbar-find-button-close =
+    .tooltiptext = Cau'r bar chwilio
+
+findbar-highlight-all2 =
+    .label = Amlygu Popeth
+    .accesskey =
+        { PLATFORM() ->
+            [macos] l
+           *[other] a
+        }
+    .tooltiptext = Amlygu pob enghraifft o'r ymadrodd
+
+findbar-case-sensitive =
+    .label = Cydweddu Maint
+    .accesskey = C
+    .tooltiptext = Chwilio gyda sensitifrwydd maint nodau
+
+findbar-match-diacritics =
+    .label = Diacritig cyfatebol
+    .accesskey = i
+    .tooltiptext = Gwahaniaethu rhwng nodau acennog a nodau sylfaenol, (e.e. wrth chwilio am “resume”, ni fydd “résumé” yn cael ei gynnig)
+
+findbar-entire-word =
+    .label = Geiriau Llawn
+    .accesskey = G
+    .tooltiptext = Chwilio'r geiriau llawn yn unig
diff --git a/l10n-cy/toolkit/toolkit/payments/payments.ftl b/l10n-cy/toolkit/toolkit/payments/payments.ftl
new file mode 100644
index 0000000000..826f443fb5
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/payments/payments.ftl
@@ -0,0 +1,69 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# This value isn't used directly, but is defined to avoid duplication
+# in the "credit-card-label-*" strings.
+#
+# Variables:
+#   $month (String): Numeric month the credit card expires
+#   $year (String): Four-digit year the credit card expires
+credit-card-expiration = Yn dod i ben ar { $month }/{ $year }
+
+## These labels serve as a description of a credit card.
+## The description must include a credit card number, and may optionally
+## include a cardholder name, an expiration date, or both, so we have
+## four variations.
+
+# Label for a credit card with a number only
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+credit-card-label-number = { $number }
+# Label for a credit card with a number and name
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $name (String): Cardholder name
+credit-card-label-number-name = { $number }, { $name }
+# Label for a credit card with a number and expiration date
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+credit-card-label-number-expiration = { $number }, { credit-card-expiration }
+# Label for a credit card with a number, name, and expiration date
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $name (String): Cardholder name
+credit-card-label-number-name-expiration = { $number }, { $name }, { credit-card-expiration }
+# Label for a credit card with a number only
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $type (String): Credit card type
+credit-card-label-number-2 = { $number }
+    .aria-label = { $type } { credit-card-label-number-2 }
+# Label for a credit card with a number and name
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $name (String): Cardholder name
+#   $type (String): Credit card type
+credit-card-label-number-name-2 = { $number }, { $name }
+    .aria-label = { $type } { credit-card-label-number-name-2 }
+# Label for a credit card with a number and expiration date
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $type (String): Credit card type
+credit-card-label-number-expiration-2 = { $number }, { credit-card-expiration }
+    .aria-label = { $type } { credit-card-label-number-expiration-2 }
+# Label for a credit card with a number, name, and expiration date
+#
+# Variables:
+#   $number (String): Partially-redacted credit card number
+#   $name (String): Cardholder name
+#   $type (String): Credit card type
+credit-card-label-number-name-expiration-2 = { $number }, { $name }, { credit-card-expiration }
+    .aria-label = { $type } { credit-card-label-number-name-expiration-2 }
diff --git a/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.ftl b/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.ftl
new file mode 100644
index 0000000000..274f38a3df
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.ftl
@@ -0,0 +1,22 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+pictureinpicture-player-title = Llun mewn Llun
+
+pictureinpicture-pause =
+    .aria-label = Oedi
+pictureinpicture-play =
+    .aria-label = Chwarae
+
+pictureinpicture-mute =
+    .aria-label = Tewi
+pictureinpicture-unmute =
+    .aria-label = Dad dewi
+
+pictureinpicture-unpip =
+    .aria-label = Anfon nôl i'r tab
+
+pictureinpicture-close =
+    .aria-label = Cau
+
diff --git a/l10n-cy/toolkit/toolkit/preferences/preferences.ftl b/l10n-cy/toolkit/toolkit/preferences/preferences.ftl
new file mode 100644
index 0000000000..9eabe33060
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/preferences/preferences.ftl
@@ -0,0 +1,61 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+password-not-set =
+    .value = (heb ei osod)
+
+failed-pw-change = Methu newid y Prif Gyfrinair.
+incorrect-pw = Wedi rhoi cyfrinair anghywir. Ceisiwch eto.
+pw-change-ok = Newidiwyd y Prif Gyfrinair yn llwyddiannus.
+
+pw-empty-warning = Ni fydd eich cyfrineiriau gwe ac e-bost, data ffurflen, nag eich allweddi preifat yn cael eu hamddiffyn.
+pw-erased-ok = Rydych wedi dileu eich Prif Gyfrinair.  { pw-empty-warning }
+pw-not-wanted = Rhybudd! Rydych wedi penderfynu peidio defnyddio Prif Gyfrinair. { pw-empty-warning }
+
+pw-change2empty-in-fips-mode = Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+
+failed-pp-change = Methu newid y Prif Gyfrinair.
+incorrect-pp = Nid ydych wedi rhoi'r Prif Gyfrinair cyfredol cywir. Ceisiwch eto.
+pp-change-ok = Mae'r Prif Gyfrinair wedi ei newid yn llwyddiannus.
+
+pp-empty-warning = Fydd eich cyfrineiriau a'ch allweddi preifat wedi'u storio ddim yn cael eu gwarchod.
+pp-erased-ok = Rydych wedi dileu eich Prif Gyfrinair.  { pp-empty-warning }
+pp-not-wanted = Rhybudd! Rydych wedi penderfynu peidio â defnyddio Prif Gyfrinair. { pp-empty-warning }
+
+pp-change2empty-in-fips-mode = Rydych ym modd FIPS. Mae FIPS angen Prif Gyfrinair nad yw'n wag.
+pw-change-success-title = Llwyddo i Newid eich Cyfrinair
+pw-change-failed-title = Methu Newid eich Cyfrinair
+pw-remove-button =
+    .label = Tynnu
+
+set-password =
+    .title = Newid Prif Gyfrinair
+
+primary-password-dialog =
+    .title = Prif Gyfrinair
+set-password-old-password = Cyfrinair cyfredol:
+set-password-new-password = Rhoi'r cyfrinair newydd:
+set-password-reenter-password = Rhoi'r cyfrinair eto:
+set-password-meter = Mesurydd ansawdd y cyfrinair
+set-password-meter-loading = Llwytho
+master-password-admin = Mae eich gweinyddwr yn mynnu bod gennych Brif Gyfrinair wedi'i osod er mwyn cadw cyfrineiriau.
+master-password-description = Mae Prif Gyfrinair yn cael ei ddefnyddio i amddiffyn gwybodaeth sensitif fel cyfrineiriau gwefannau.  Os fyddwch yn creu Prif Gyfrinair bydd gofyn i chi ei rhoi unwaith y sesiwn pan fydd { -brand-short-name } yn estyn gwybodaeth wedi ei gadw'n ddiogel gan y cyfrinair.
+master-password-warning = Gwnewch yn siŵr eich bod yn cofio'r Prif Gyfrinair.  Os byddwch yn anghofio eich Prif Gyfieithiad, ni fydd modd i chi gael mynediad at unrhyw wybodaeth mae'n ei amddiffyn.
+
+remove-password =
+    .title = Tynnu'r Prif Gyfrinair
+primary-password-admin = Mae eich gweinyddwr yn mynnu bod gennych Brif Gyfrinair wedi'i osod er mwyn cadw mewngofnodion a chyfrineiriau.
+primary-password-description = Mae Prif Gyfrinair yn cael ei ddefnyddio i ddiogelu gwybodaeth sensitif fel cyfrineiriau gwefannau.  Os fyddwch yn creu Prif Gyfrinair bydd gofyn i chi ei rhoi unwaith y sesiwn pan fydd { -brand-short-name } yn estyn gwybodaeth wedi ei gadw'n ddiogel gan y cyfrinair.
+primary-password-warning = Gwnewch yn siŵr eich bod yn cofio'r Prif Gyfrinair.  Os byddwch yn anghofio eich Prif Gyfieithiad, ni fydd modd i chi gael mynediad at unrhyw wybodaeth mae'n ei ddiogelu.
+
+remove-primary-password =
+    .title = Tynnu'r Prif Gyfrinair
+remove-info =
+    .value = Rhaid rhoi eich cyfrinair presennol cyn parhau:
+remove-warning1 = Mae eich Prif Gyfrinair yn cael ei ddefnyddio i ddiogelu data sensitif fel cyfrineiriau gwefannau.
+remove-warning2 = Os byddwch yn tynnu eich Prif Gyfrinair ni fydd eich gwybodaeth wedi ei ddiogelu os yw eich cyfrifiadur wedi ei gyfaddawdu.
+remove-primary-password-warning1 = Mae eich Prif Gyfrinair yn cael ei ddefnyddio i ddiogelu data sensitif fel cyfrineiriau gwefannau.
+remove-primary-password-warning2 = Os byddwch yn tynnu eich Prif Gyfrinair ni fydd eich gwybodaeth wedi ei ddiogelu os yw eich cyfrifiadur wedi ei gyfaddawdu.
+remove-password-old-password =
+    .value = Cyfrinair cyfredol:
diff --git a/l10n-cy/toolkit/toolkit/printing/printDialogs.ftl b/l10n-cy/toolkit/toolkit/printing/printDialogs.ftl
new file mode 100644
index 0000000000..0fe7753937
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/printing/printDialogs.ftl
@@ -0,0 +1,112 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+print-setup =
+    .title = Gosodiad Tudalen
+custom-prompt-title = Cyfaddasu…
+custom-prompt-prompt = Rhowch destun pennyn /troedyn cyfaddas
+basic-tab =
+    .label = Fformatio a Dewisiadau
+advanced-tab =
+    .label = Ymylon a Phennyn/Troedyn
+format-group-label =
+    .value = Fformat
+orientation-label =
+    .value = Cyfeiriadaeth:
+portrait =
+    .label = Portread
+    .accesskey = P
+landscape =
+    .label = Tirwedd
+    .accesskey = T
+scale =
+    .label = Graddfa:
+    .accesskey = r
+scale-percent =
+    .value = %
+shrink-to-fit =
+    .label = Cywasgu i Led y Dudalen
+    .accesskey = L
+options-group-label =
+    .value = Dewisiadau
+print-bg =
+    .label = Argraffu Lliwiau'r Cefndir (lliwiau a delweddau)
+    .accesskey = A
+margin-group-label-inches =
+    .value = Ymylon (modfedd)
+margin-group-label-metric =
+    .value = Ymylon (milimetr)
+margin-top =
+    .value = Brig:
+    .accesskey = B
+margin-top-invisible =
+    .value = Brig:
+margin-bottom =
+    .value = Gwaelod:
+    .accesskey = G
+margin-bottom-invisible =
+    .value = Gwaelod:
+margin-left =
+    .value = Chwith:
+    .accesskey = C
+margin-left-invisible =
+    .value = Chwith:
+margin-right =
+    .value = De:
+    .accesskey = D
+margin-right-invisible =
+    .value = De:
+header-footer-label =
+    .value = Penynnau a Throedynnau
+hf-left-label =
+    .value = Chwith:
+hf-center-label =
+    .value = Canoli:
+hf-right-label =
+    .value = De:
+header-left-tip =
+    .tooltiptext = Pennyn chwith
+header-center-tip =
+    .tooltiptext = Pennyn canol
+header-right-tip =
+    .tooltiptext = Pennyn de
+footer-left-tip =
+    .tooltiptext = Troedyn chwith
+footer-center-tip =
+    .tooltiptext = Troedyn canol
+footer-right-tip =
+    .tooltiptext = Troedyn de
+hf-blank =
+    .label = --gwag--
+hf-title =
+    .label = Teitl
+hf-url =
+    .label = URL
+hf-date-and-time =
+    .label = Dyddiad/Amser
+hf-page =
+    .label = Tudalen #
+hf-page-and-total =
+    .label = Tudalen # o #
+hf-custom =
+    .label = Cyfaddasu…
+print-preview-window =
+    .title = Rhagolwg Argraffu
+print-title =
+    .value = Teitl:
+print-preparing =
+    .value = Paratoi…
+print-progress =
+    .value = Cynnydd:
+print-window =
+    .title = Argraffu
+print-complete =
+    .value = Argraffu wedi ei Gwblhau.
+
+# Variables
+# $percent (integer) - Number of printed percentage
+print-percent =
+    .value = { $percent }%
+dialog-cancel-label = Diddymu
+dialog-close-label = Cau
diff --git a/l10n-cy/toolkit/toolkit/printing/printPreview.ftl b/l10n-cy/toolkit/toolkit/printing/printPreview.ftl
new file mode 100644
index 0000000000..21def775da
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/printing/printPreview.ftl
@@ -0,0 +1,71 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+printpreview-simplify-page-checkbox =
+    .label = Symleiddio Tudalen
+    .accesskey = S
+    .tooltiptext = Nid oes modd symleiddio'r dudalen yn awtomatig
+printpreview-simplify-page-checkbox-enabled =
+    .label = { printpreview-simplify-page-checkbox.label }
+    .accesskey = { printpreview-simplify-page-checkbox.accesskey }
+    .tooltiptext = Newid cynllun ar gyfer darllen haws
+printpreview-close =
+    .label = Cau
+    .accesskey = C
+printpreview-portrait =
+    .label = Portread
+    .accesskey = o
+printpreview-landscape =
+    .label = Tirlun
+    .accesskey = l
+printpreview-scale =
+    .value = Graddfa:
+    .accesskey = G
+printpreview-shrink-to-fit =
+    .label = Lleihau i'r Maint
+printpreview-custom =
+    .label = Cyfaddasu…
+printpreview-print =
+    .label = Argraffu…
+    .accesskey = A
+printpreview-of =
+    .value = o
+printpreview-custom-scale-prompt-title = Graddfa Cyfaddasu
+printpreview-page-setup =
+    .label = Gosodiad Tudalen…
+    .accesskey = u
+printpreview-page =
+    .value = Tudalen:
+    .accesskey = a
+# Variables
+# $sheetNum (integer) - The current sheet number
+# $sheetCount (integer) - The total number of sheets to print
+printpreview-sheet-of-sheets = { $sheetNum } o { $sheetCount }
+
+## Variables
+## $percent (integer) - menuitem percent label
+## $arrow (String) - UTF-8 arrow character for navigation buttons
+
+printpreview-percentage-value =
+    .label = { $percent }%
+printpreview-homearrow =
+    .label = { $arrow }
+    .tooltiptext = Tudalen gyntaf
+printpreview-previousarrow =
+    .label = { $arrow }
+    .tooltiptext = Tudalen blaenorol
+printpreview-nextarrow =
+    .label = { $arrow }
+    .tooltiptext = Tudalen nesaf
+printpreview-endarrow =
+    .label = { $arrow }
+    .tooltiptext = Tudalen olaf
+printpreview-homearrow-button =
+    .title = Tudalen gyntaf
+printpreview-previousarrow-button =
+    .title = Tudalen flaenorol
+printpreview-nextarrow-button =
+    .title = Tudalen nesaf
+printpreview-endarrow-button =
+    .title = Tudalen olaf
diff --git a/l10n-cy/toolkit/toolkit/printing/printUI.ftl b/l10n-cy/toolkit/toolkit/printing/printUI.ftl
new file mode 100644
index 0000000000..9bde9613ce
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/printing/printUI.ftl
@@ -0,0 +1,106 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+printui-title = Argraffu
+# Dialog title to prompt the user for a filename to save print to PDF.
+printui-save-to-pdf-title = Cadw Fel
+# Variables
+# $sheetCount (integer) - Number of paper sheets
+printui-sheets-count =
+    { $sheetCount ->
+        [zero] { $sheetCount } dalen o bapur
+        [one] { $sheetCount } dalen o bapur
+        [two] { $sheetCount } ddalen o bapur
+        [few] { $sheetCount } dalen o bapur
+        [many] { $sheetCount } dalen o bapur
+       *[other] { $sheetCount } dalen o bapur
+    }
+printui-page-range-all = Y Cyfan
+printui-page-range-custom = Cyfaddasu
+printui-page-range-label = Tudalen
+printui-page-range-picker =
+    .aria-label = Dewis yr ystod tudalen
+printui-page-custom-range-input =
+    .aria-label = Rhowch ystod tudalen cyfaddas
+    .placeholder = e.e. 2-6, 9, 12-16
+# Section title for the number of copies to print
+printui-copies-label = Copïau
+printui-orientation = Cyfeiriad
+printui-landscape = Tirlun
+printui-portrait = Portread
+# Section title for the printer or destination device to target
+printui-destination-label = Cyrchfan
+printui-destination-pdf-label = Cadw i PDF
+printui-more-settings = Rhagor o osodiadau
+printui-less-settings = Llai o osodiadau
+printui-paper-size-label = Maint papur
+# Section title (noun) for the print scaling options
+printui-scale = Graddfa
+printui-scale-fit-to-page-width = Yn ffitio i led y dudalen
+# Label for input control where user can set the scale percentage
+printui-scale-pcent = Graddfa
+# Section title (noun) for the two-sided print options
+printui-two-sided-printing = Argraffu dwy ochr
+printui-duplex-checkbox = Argraffu ar y ddwy ochr
+# Section title for miscellaneous print options
+printui-options = Dewisiadau
+printui-headers-footers-checkbox = Argraffu penynnau a throedynnau
+printui-backgrounds-checkbox = Argraffu cefndiroedd
+printui-selection-checkbox = Argraffu'r dewis yn unig
+printui-color-mode-label = Modd lliw
+printui-color-mode-color = Lliw
+printui-color-mode-bw = Du a gwyn
+printui-margins = Ymylon
+printui-margins-default = Rhagosodiad
+printui-margins-min = Lleiafswm
+printui-margins-none = Dim
+printui-margins-custom-inches = Cyfaddas (modfeddi)
+printui-margins-custom-top = Brig
+printui-margins-custom-top-inches = Brig (modfeddi)
+printui-margins-custom-bottom = Gwaelod
+printui-margins-custom-bottom-inches = Gwaelod (modfeddi)
+printui-margins-custom-left = Chwith
+printui-margins-custom-left-inches = Chwith (modfeddi)
+printui-margins-custom-right = De
+printui-margins-custom-right-inches = De (modfeddi)
+printui-system-dialog-link = Argraffu gan ddefnyddio deialog y system ...
+printui-primary-button = Argraffu
+printui-primary-button-save = Cadw
+printui-cancel-button = Diddymu
+printui-close-button = Cau
+printui-loading = Paratoi Rhagolwg
+# Reported by screen readers and other accessibility tools to indicate that
+# the print preview has focus.
+printui-preview-label =
+    .aria-label = Rhagolwg Argraffu
+printui-pages-per-sheet = Tudalennau fesul dalen
+# This is shown next to the Print button with an indefinite loading spinner
+# when the user prints a page and it is being sent to the printer.
+printui-print-progress-indicator = Argraffu…
+printui-print-progress-indicator-saving = Yn cadw…
+
+## Paper sizes that may be supported by the Save to PDF destination:
+
+printui-paper-a5 = A5
+printui-paper-a4 = A4
+printui-paper-a3 = A3
+printui-paper-a2 = A2
+printui-paper-a1 = A1
+printui-paper-a0 = A0
+printui-paper-b5 = B5
+printui-paper-b4 = B4
+printui-paper-jis-b5 = JIS-B5
+printui-paper-jis-b4 = JIS-B4
+printui-paper-letter = US Letter
+printui-paper-legal = US Legal
+printui-paper-tabloid = Tabloid
+
+## Error messages shown when a user has an invalid input
+
+printui-error-invalid-scale = Rhaid i'r raddfa fod yn rhif rhwng 10 a 200.
+printui-error-invalid-margin = Rhowch ymyl ddilys ar gyfer y maint papur a ddewiswyd.
+# Variables
+# $numPages (integer) - Number of pages
+printui-error-invalid-range = Rhaid i'r raddfa fod yn rhif rhwng 10 a { $numPages }.
+printui-error-invalid-start-overflow = Rhaid i rif y dudalen “o” fod yn llai na rhif y dudalen “i”.
diff --git a/l10n-cy/toolkit/toolkit/updates/elevation.ftl b/l10n-cy/toolkit/toolkit/updates/elevation.ftl
new file mode 100644
index 0000000000..5c8dd3ab4c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/updates/elevation.ftl
@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# This is temporary until bug 1521632 is fixed
+
+elevation-update-wizard =
+    .title = Diweddaru Meddalwedd
+elevation-details-link-label =
+    .value = Manylion
+elevation-error-manual = Gallwch ddiweddaru { -brand-short-name } gyda llaw drwy ymweld â'r dolenni a llwytho'r fersiwn diweddaraf:
+elevation-finished-page = Diweddariad yn Barod i'w Osod
+elevation-finished-background-page = Mae diweddariad diogelwch a sefydlogrwydd ar gyfer { -brand-short-name } wedi ei lwytho i lawr ac mae'n barod i'w osod.
+elevation-finished-background = Diweddaru:
+elevation-more-elevated = Mae'r diweddariad angen breintiau gweinyddwr. Bydd y diweddariad yn cael ei osod y tro nesaf y bydd { -brand-short-name } yn cychwyn. Mae modd ailgychwyn { -brand-short-name } nawr, parhau i weithio ac ailgychwyn yn hwyrach, neu wrthod y diweddariad.
diff --git a/l10n-cy/toolkit/toolkit/updates/history.ftl b/l10n-cy/toolkit/toolkit/updates/history.ftl
new file mode 100644
index 0000000000..75b04463eb
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/updates/history.ftl
@@ -0,0 +1,27 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+history-title = Hanes Diweddaru
+history-intro = Mae'r diweddariadau canlynol wedi eu gosod
+
+close-button-label =
+    .buttonlabelcancel = Cau
+    .title = Hanes Diweddaru
+
+no-updates-label = Dim diweddariadau wedi eu gosod eto
+name-header = Enw'r Diweddariad
+date-header = Dyddiad Gosod
+type-header = Math
+state-header = Sir/Talaith
+
+# Used to display update history
+#
+# Variables:
+#   $name (String): name of the update
+#   $buildID (String): build identifier from the local updates.xml
+update-full-build-name = { $name } ({ $buildID })
+
+update-details = Manylion
+update-installed-on = Gosodwyd ar: { $date }
+update-status = Statws: { $status }