Adding upstream version 115.8.0esr.upstream/115.8.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
author: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 01:47:29 +0000
committer: Daniel Baumann <daniel.baumann@progress-linux.org> 2024-04-19 01:47:29 +0000
commit: 0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
tree: a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /l10n-cy/toolkit
parent: Initial commit. (diff)
download: firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz
firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip
118 files changed, 7333 insertions, 0 deletions
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..d830a29b86
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/mac/platformKeys.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/.
+
+# 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 Command key - clover leaf symbol (ctrl-q)
+VK_COMMAND_OR_WIN=\u2318
+
+# 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..fded02a68e
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/unix/platformKeys.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/.
+
+# 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 Super/Hyper key
+VK_COMMAND_OR_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..1df027dccf
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global-platform/win/platformKeys.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/.
+
+# 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 Win key
+VK_COMMAND_OR_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/aboutStudies.properties b/l10n-cy/toolkit/chrome/global/aboutStudies.properties
new file mode 100644
index 0000000000..3dac37ecf4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/aboutStudies.properties
@@ -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 (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 = Darllen 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$S.
diff --git a/l10n-cy/toolkit/chrome/global/autocomplete.properties b/l10n-cy/toolkit/chrome/global/autocomplete.properties
new file mode 100644
index 0000000000..105e0ff25c
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/autocomplete.properties
@@ -0,0 +1,9 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# LOCALIZATION NOTE (bookmarkKeywordSearch): This is the title of autocomplete
+# entries that are bookmark keyword searches.  %1$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/commonDialogs.properties b/l10n-cy/toolkit/chrome/global/commonDialogs.properties
new file mode 100644
index 0000000000..7c624967a4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/commonDialogs.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/.
+
+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:
+ScriptDlgNullPrincipalHeading=Mae'r dudalen hon yn dweud:
+ScriptDialogLabel=Atal y dudalen hon rhag creu deialogau ychwanegol
+ScriptDialogLabelNullPrincipal=Peidio â gadael i'r wefan hon eich annog chi eto
+# LOCALIZATION NOTE (ScriptDialogLabelContentPrincipal):
+# %S is either the domain and port of the site prompting, or the name of
+# an add-on prompting.
+ScriptDialogLabelContentPrincipal=Peidio â gadael i %S eich annog chi eto
+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
+EnterCredentials=Mae'r wefan hon yn gofyn i chi fewngofnodi.
+# %S is the username for which a password is requested.
+EnterPasswordOnlyFor=Mae'r wefan hon yn gofyn i chi fewngofnodi fel %S.
+# %S is the domain of the site being accessed.
+EnterCredentialsCrossOrigin=Mae'r wefan hon yn gofyn i chi fewngofnodi. Rhybudd: Bydd eich manylion mewngofnodi yn cael ei rhannu â %S, nid y wefan rydych chi'n ymweld â hi ar hyn o bryd.
+SignIn=Mewngofnodi
diff --git a/l10n-cy/toolkit/chrome/global/contentAreaCommands.properties b/l10n-cy/toolkit/chrome/global/contentAreaCommands.properties
new file mode 100644
index 0000000000..40624dda1d
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/contentAreaCommands.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/.
+
+# context menu strings
+
+SaveImageTitle=Cadw Delwedd
+SaveMediaTitle=Cadw'r Cyfryngau
+SaveVideoTitle=Cadw Fideo
+SaveAudioTitle=Cadw Sain
+SaveLinkTitle=Cadw Fel
+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 (UntitledSaveFileName):
+#    This is the default filename used when saving a file if a filename could
+#    not be determined or if a filename was invalid. A period and file
+#    extension may be appended to this string.
+UntitledSaveFileName=Di-deitl
+
+# 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/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/extensions.properties b/l10n-cy/toolkit/chrome/global/extensions.properties
new file mode 100644
index 0000000000..ffdb95b670
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/extensions.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 (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 = Darllen 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 = Darllen 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$S, yn cuddio rhai o'ch tabiau. Gallwch gael mynediad at eich holl dabiau o %2$S.
+tabHideControlled.learnMore = Darllen 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..934cf85b12
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/filepicker.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: 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
+
+pdfTitle=Ffeiliau PDF
+
+formatLabel=Fformat:
+selectedFileNotReadableError=Nid oes gan y ffeil a ddewiswyd ganiatâd darllen
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..fc883339d8
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/intl.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/.
+
+# 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 (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..38eeb1f140
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/keys.properties
@@ -0,0 +1,70 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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 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
+
+# LOCALIZATION NOTE : BLOCK maybe GLYPHS
+VK_TAB=Tab
+VK_BACK=Backspace
+VK_DELETE=Del
+# LOCALIZATION NOTE : BLOCK end maybe GLYPHS
+# LOCALIZATION NOTE : BLOCK typing state keys
+VK_HOME=Cartref
+VK_END=End
+
+VK_ESCAPE=Esc
+VK_INSERT=Ins
+# LOCALIZATION NOTE : BLOCK end
diff --git a/l10n-cy/toolkit/chrome/global/narrate.properties b/l10n-cy/toolkit/chrome/global/narrate.properties
new file mode 100644
index 0000000000..9847958b1e
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/narrate.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/.
+
+# "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.
+# %S is the keyboard shortcut for the listen command
+listen-label = Gwrando (%S)
+back = Nôl
+# %S is the keyboard shortcut for the start command
+start-label = Cychwyn (%S)
+# %S is the keyboard shortcut for the stop command
+stop-label = Atal (%S)
+# Keyboard shortcut to toggle the narrate feature
+narrate-key-shortcut = N
+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/printdialog.properties b/l10n-cy/toolkit/chrome/global/printdialog.properties
new file mode 100644
index 0000000000..7044bdc223
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/global/printdialog.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/.
+
+# 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
+
+# These are for the summary view in the Mac dialog:
+summarySelectionOnlyTitle=Dewis Argraffu
+summaryShrinkToFitTitle=Lleihau i'r Maint
+summaryPrintBGColorsTitle=Argraffu Lliwiau BG
+summaryPrintBGImagesTitle=Argraffu Delweddau BG
+summaryHeaderTitle=Pennyn Tudalen
+summaryFooterTitle=Troedyn Tudalen
+summaryNAValue=Dim Ar Gael
+summaryOnValue=Ymlaen
+summaryOffValue=Diffodd
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/viewSource.properties b/l10n-cy/toolkit/chrome/global/viewSource.properties
new file mode 100644
index 0000000000..25fed52db6
--- /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 linell
+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..e59d5604b4
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/downloads.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/.
+
+# Desktop folder name for downloaded files
+downloadsFolder=Llwythi i lawr
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..bc160e437b
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/downloads/unknownContentType.properties
@@ -0,0 +1,23 @@
+# -*- 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)
+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/profile/profileSelection.properties b/l10n-cy/toolkit/chrome/mozapps/profile/profileSelection.properties
new file mode 100644
index 0000000000..3706e38ef2
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/mozapps/profile/profileSelection.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/.
+
+# 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
+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..476f39643a
--- /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
+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
+check_error-update_url_not_available=Nid yw'r URL diweddaru ar gael
+check_error-connection_aborted=Cysylltiad wedi cau
diff --git a/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties b/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties
new file mode 100644
index 0000000000..8be8411034
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/passwordmgr/passwordmgr.properties
@@ -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/.
+
+rememberPassword = Defnyddio'r Rheolwr Cyfrinair i gofio'r cyfrinair.
+savePasswordTitle = Cadarnhau
+# LOCALIZATION NOTE (saveLoginMsg2, saveLoginMsgNoUser2):
+# %S is the login's hostname.
+saveLoginMsg2 = Cadw mewngofnod %S?
+saveLoginMsgNoUser2 = Cadw cyfrinair %S?
+saveLoginButtonAllow.label = Cadw
+saveLoginButtonAllow.accesskey = C
+saveLoginButtonDeny.label = Peidio â Chadw
+saveLoginButtonDeny.accesskey = P
+saveLoginButtonNever.label = Peidio Byth â Chadw
+saveLoginButtonNever.accesskey = P
+# LOCALIZATION NOTE (updateLoginMsg3, updateLoginMsgNoUser3):
+# %S is the login's hostname.
+updateLoginMsg3 = Diweddaru mewngofnod %S?
+updateLoginMsgNoUser3 = Diweddaru cyfrinair %S?
+updateLoginMsgAddUsername2 = Ychwanegu enw defnyddiwr i gyfrinair wedi’i gadw?
+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$S?
+# LOCALIZATION NOTE (rememberPasswordMsgNoUsername):
+# String is the login's hostname.
+rememberPasswordMsgNoUsername = Hoffech chi gofio'r cyfrinair ar %S?
+# LOCALIZATION NOTE (noUsernamePlaceholder):
+# This is displayed in place of the username when it is missing.
+noUsernamePlaceholder=Dim enw defnyddiwr
+togglePasswordLabel=Dangos cyfrinair
+togglePasswordAccessKey2=d
+notNowButtonText = &Nid Nawr
+neverForSiteButtonText = &Byth ar Gyfer y Wefan yma
+rememberButtonText = &Cofio
+passwordChangeTitle = Cadarnhau Newid Cyfrinair
+# LOCALIZATION NOTE (updatePasswordMsg):
+# String is the username for the login.
+updatePasswordMsg = Hoffech chi ddiweddaru cyfrinair "%S"?
+updatePasswordMsgNoUser = Hoffech chi ddiweddaru'r cyfrinair?
+userSelectText2 = Dewis pa fewngofnod i'w ddiweddaru:
+loginsDescriptionAll2=Mae'r cyfrineiriau ar gyfer y gwefannau hyn ar gadw ar eich cyfrifiadur
+
+# LOCALIZATION NOTE (useASecurelyGeneratedPassword):
+# Shown in the autocomplete popup to allow filling a generated password into a password field.
+useASecurelyGeneratedPassword=Defnyddiwch Gyfrinair sydd wedi ei Gynhyrchu'n Ddiogel
+# LOCALIZATION NOTE (generatedPasswordWillBeSaved):
+# %S will contain the brandShorterName. This informs the user that the generated password will be automatically saved.
+generatedPasswordWillBeSaved=Bydd %S yn cadw'r cyfrinair hwn ar gyfer y wefan hon.
+# LOCALIZATION NOTE (loginHostAge):
+# This is used to show the context menu login items with their age.
+# 1st string is the username for the login, 2nd is the login's age.
+loginHostAge=%1$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$S
+insecureFieldWarningLearnMore = Darllen Rhagor
+
+# LOCALIZATION NOTE (viewSavedLogins.label):
+# This label is used in the footer of login autocomplete menus.
+viewSavedLogins.label= Gweld Mewngofnodion wedi eu Cadw
+
+# LOCALIZATION NOTE (managePasswords.label):
+# This label is used in the footer of login autocomplete menus.
+managePasswords.label= Rheoli Cyfrineiriau
diff --git a/l10n-cy/toolkit/chrome/places/places.properties b/l10n-cy/toolkit/chrome/places/places.properties
new file mode 100644
index 0000000000..2db1ecdd38
--- /dev/null
+++ b/l10n-cy/toolkit/chrome/places/places.properties
@@ -0,0 +1,32 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+BookmarksMenuFolderTitle=Dewislen Nodau Tudalen
+BookmarksToolbarFolderTitle=Bar Offer Nodau Tudalen
+OtherBookmarksFolderTitle=Nodau Tudalen Eraill
+TagsFolderTitle=Tagiau
+MobileBookmarksFolderTitle=Nodau Tudalen Symudol
+OrganizerQueryHistory=Hanes
+OrganizerQueryDownloads=Llwythi i lawr
+OrganizerQueryAllBookmarks=Pob Nod Tudalen
+
+# LOCALIZATION NOTE :
+# These are used to generate history containers when history is grouped by date
+finduri-AgeInDays-is-0=Heddiw
+finduri-AgeInDays-is-1=Ddoe
+finduri-AgeInDays-is=%S diwrnod yn ôl
+finduri-AgeInDays-last-is=Y %S diwrnod diwethaf
+finduri-AgeInDays-isgreater=Hŷn na %S diwrnod
+finduri-AgeInMonths-is-0=Y mis yma
+finduri-AgeInMonths-isgreater=Hŷn na %S mis
+
+# LOCALIZATION NOTE (localhost):
+# This is used to generate local files container when history is grouped by site
+localhost=(ffeiliau lleol)
+
+# LOCALIZATION NOTE (backupFileSizeText):
+# The string is used for showing file size of each backup in the "fileRestorePopup" popup
+# %1$S is the file size
+# %2$S is the file size unit
+backupFileSizeText=%1$S %2$S
diff --git a/l10n-cy/toolkit/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/services/accounts.ftl b/l10n-cy/toolkit/services/accounts.ftl
new file mode 100644
index 0000000000..c77738b816
--- /dev/null
+++ b/l10n-cy/toolkit/services/accounts.ftl
@@ -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/.
+
+# Variables:
+#   $user (String): the user name (e.g. "Ed")
+#   $system (String): the operating system (e.g. "Android")
+account-client-name = { $user }'s { -brand-short-name } ar { $system }
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..5e7ddc0e9d
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutAddons.ftl
@@ -0,0 +1,502 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+addons-page-title = Rheolwr Ychwanegion
+search-header =
+    .placeholder = Search addons.mozilla.org
+    .searchbuttonlabel = Chwilio
+
+## Variables
+##   $domain - Domain name where add-ons are available (e.g. addons.mozilla.org)
+
+list-empty-get-extensions-message = Cewch estyniadau a themâu yn <a data-l10n-name="get-extensions">{ $domain }</a>
+list-empty-get-dictionaries-message = Cael geiriaduron o <a data-l10n-name="get-extensions">{ $domain }</a>
+list-empty-get-language-packs-message = Cael pecynnau iaith o <a data-l10n-name="get-extensions">{ $domain }</a>
+
+##
+
+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 = Darllen rhagor am ychwanegion
+help-button = Cefnogaeth Ychwanegion
+sidebar-help-button-title =
+    .title = Cefnogaeth Ychwanegion
+addons-settings-button = Gosodiadau { -brand-short-name }
+sidebar-settings-button-title =
+    .title = Gosodiadau { -brand-short-name }
+show-unsigned-extensions-button =
+    .label = Nid oedd modd dilysu rhai estyniadau
+show-all-extensions-button =
+    .label = Dangos pob estyniad
+detail-version =
+    .label = Fersiwn
+detail-last-updated =
+    .label = Diweddarwyd Diwethaf
+addon-detail-description-expand = Dangos rhagor
+addon-detail-description-collapse = Dangos llai
+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 = Rhagosodiad
+    .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">Darllen 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 at 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 â Chaniatáu
+    .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 = Darllen 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">Darllen 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
+addon-category-sitepermission = Caniatâd Gwefan
+addon-category-sitepermission-title =
+    .title = Caniatâd Gwefan
+# String displayed in about:addons in the Site Permissions section
+# Variables:
+#  $host (string) - DNS host name for which the webextension enables permissions
+addon-sitepermission-host = Caniatâd Gwefan { $host }
+
+## 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-safe-mode2 =
+    .message = Mae pob ychwanegyn wedi eu hanalluogi gan y modd diogel.
+extensions-warning-check-compatibility2 =
+    .message = 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-security2 =
+    .message = 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
+extensions-warning-imported-addons2 =
+    .message = Gorffennwch osod yr estyniadau a fewnforiwyd i { -brand-short-name }.
+extensions-warning-imported-addons-button = Gosod Estyniadau
+
+## 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 assigned to more than one add-on
+# Variables:
+#   $shortcut (string) - Shortcut string for the add-on
+shortcuts-duplicate-warning-message2 =
+    .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 }
+# Variables:
+#   $numberToShow (number) - Number of other elements available to show
+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.
+# Notice to make user aware that the recommendations are personalized.
+discopane-notice-recommendations2 =
+    .message =
+        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 = Darllen 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
+find-more-themes = Canfod themâu eraill
+# 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 = Analluogi
+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-heading2 = Themâu wedi'u Cadw
+plugin-enabled-heading = Galluogwyd
+plugin-disabled-heading = Analluogwyd
+dictionary-enabled-heading = Galluogwyd
+dictionary-disabled-heading = Analluogwyd
+locale-enabled-heading = Galluogwyd
+locale-disabled-heading = Analluogwyd
+sitepermission-enabled-heading = Galluogwyd
+sitepermission-disabled-heading = Analluogwyd
+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.
+# Message for add-ons with a staged pending update.
+install-postponed-message2 =
+    .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.
+# Variables:
+#   $addon (string) - Name of the add-on
+pending-uninstall-description2 =
+    .message = Mae { $addon } wedi ei dynnu.
+pending-uninstall-undo-button = Dadwneud
+addon-detail-updates-label = Caniatáu diweddariadau awtomatig
+addon-detail-updates-radio-default = Rhagosodiad
+addon-detail-updates-radio-on = Ymlaen
+addon-detail-updates-radio-off = Diffodd
+addon-detail-update-check-label = Gwirio am Ddiweddariadau
+install-update-button = Diweddaru
+# aria-label associated to the updates row to help screen readers to announce the group
+# of input controls being entered.
+addon-detail-group-label-updates =
+    .aria-label = { addon-detail-updates-label }
+# 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 â Chaniatáu
+# aria-label associated to the private browsing row to help screen readers to announce the group
+# of input controls being entered.
+addon-detail-group-label-private-browsing =
+    .aria-label = { detail-private-browsing-label }
+
+## "sites with restrictions" (internally called "quarantined") are special domains
+## where add-ons are normally blocked for security reasons.
+
+# Used as a description for the option to allow or block an add-on on quarantined domains.
+addon-detail-quarantined-domains-label = Rhedeg ar wefannau gyda chyfyngiadau
+# Used as help text part of the quarantined domains UI controls row.
+addon-detail-quarantined-domains-help = Pan yn cael ei ganiatáu, bydd gan yr estyniad fynediad i wefannau sy'n cael eu cyfyngu gan { -vendor-short-name }. Caniatewch dim ond os ydych chi'n ymddiried yn yr estyniad hwn.
+# Used as label and tooltip text on the radio inputs associated to the quarantined domains UI controls.
+addon-detail-quarantined-domains-allow = Caniatáu
+addon-detail-quarantined-domains-disallow = Peidio Caniatáu
+# aria-label associated to the quarantined domains exempt row to help screen readers to announce the group.
+addon-detail-group-label-quarantined-domains =
+    .aria-label = { addon-detail-quarantined-domains-label }
+
+## 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 }
+# 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 = Yn 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 = Darllen rhagor am ganiatâd
+recommended-extensions-heading = Estyniadau Cymeradwy
+recommended-themes-heading = Themâu Cymeradwy
+# Variables:
+#   $hostname (string) - Host where the permissions are granted
+addon-sitepermissions-required = Yn caniatáu'r galluoedd canlynol i <span data-l10n-name="hostname">{ $hostname }</span>:
+# 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
+sitepermission-heading = Rheoli Eich Caniatâd Gwefan
+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
+
+## Detail notifications
+## Variables:
+##   $name (string) - Name of the add-on.
+
+# Variables:
+#   $version (string) - Application version.
+details-notification-incompatible = Mae { $name } yn anghydnaws â { -brand-short-name } { $version }.
+# Variables:
+#   $version (string) - Application version.
+details-notification-incompatible2 =
+    .message = Mae { $name } yn anghydnaws â { -brand-short-name } { $version }.
+details-notification-incompatible-link = Rhagor o Wybodaeth
+details-notification-unsigned-and-disabled = Nid oedd modd dilysu { $name } i'w ddefnyddio yn { -brand-short-name } ac mae wedi ei analluogi.
+details-notification-unsigned-and-disabled2 =
+    .message = Nid oedd modd dilysu { $name } i'w ddefnyddio yn { -brand-short-name } ac mae wedi ei analluogi.
+details-notification-unsigned-and-disabled-link = Rhagor o Wybodaeth
+details-notification-unsigned = Nid oedd modd dilysu { $name } i'w defnyddio yn { -brand-short-name }. Cymerwch ofal.
+details-notification-unsigned2 =
+    .message = Nid oedd modd dilysu { $name } i'w defnyddio yn { -brand-short-name }. Cymerwch ofal.
+details-notification-unsigned-link = Rhagor o Wybodaeth
+details-notification-blocked = Mae { $name } wedi ei analluogi o ganlyniad i faterion diogelwch a sefydlogrwydd.
+details-notification-blocked2 =
+    .message = Mae { $name } wedi ei analluogi o ganlyniad i faterion diogelwch a sefydlogrwydd.
+details-notification-blocked-link = Rhagor o Wybodaeth
+details-notification-softblocked = Mae'n hysbys fod { $name } yn achosi anawsterau diogelwch a sefydlogrwydd.
+details-notification-softblocked2 =
+    .message = Mae'n hysbys fod { $name } yn achosi anawsterau diogelwch a sefydlogrwydd.
+details-notification-softblocked-link = Rhagor o Wybodaeth
+details-notification-gmp-pending = Bydd { $name } yn cael ei osod yn fuan.
+details-notification-gmp-pending2 =
+    .message = Bydd { $name } yn cael ei osod yn fuan.
+
+## Gecko Media Plugins (GMPs)
+
+plugins-gmp-license-info = Manylion trwyddedu
+plugins-gmp-privacy-info = Manylion Preifatrwydd
+plugins-openh264-name = OpenH264 Video Codec wedi ei ddarparu gan Cisco Systems, Inc.
+plugins-openh264-description = 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 darllen rhagor am ei ddefnyddio.
+plugins-widevine-name = Mae'r Widevine Content Decryption Module wedi ei ddarparu gan Google Inc.
+plugins-widevine-description = 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.
diff --git a/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl b/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl
new file mode 100644
index 0000000000..9552cfd9f0
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutCompat.ftl
@@ -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/.
+
+label-disable = Analluogi
+label-enable = Galluogi
+label-interventions = Ymyriadau
+# Variables:
+#   $bug (string) - Bug number
+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
+
+## Do not translate "SmartBlock". For reference, SmartBlock is a feature
+## of Firefox anti-tracking which fixes website breakage caused when
+## trackers are blocked, by acting just enough like those trackers to fix the
+## breakage. SmartBlock also contains special fixes for sites broken by
+## Firefox's Total Cookie Protection feature.
+
+label-smartblock = Atgyweiriadau SmartBlock
+text-no-smartblock = Nid oes unrhyw atgyweiriadau SmartBlock yn cael eu defnyddio
diff --git a/l10n-cy/toolkit/toolkit/about/aboutGlean.ftl b/l10n-cy/toolkit/toolkit/about/aboutGlean.ftl
new file mode 100644
index 0000000000..b6f4240b50
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutGlean.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/.
+
+
+### "FOG", "Glean", and "Glean SDK" should remain in English.
+
+-fog-brand-name = FOG
+-glean-brand-name = Glean
+glean-sdk-brand-name = SDK { -glean-brand-name }
+glean-debug-ping-viewer-brand-name = Teclyn Dadfygio Pingiau { -glean-brand-name }
+about-glean-page-title2 = Ynghylch { -glean-brand-name }
+about-glean-header = Ynghylch { -glean-brand-name }
+about-glean-interface-description =
+    Mae <a data-l10n-name="glean-sdk-doc-link">{ glean-sdk-brand-name }</a>
+    yn lyfrgell casglu data sy'n cael ei ddefnyddio mewn projectau { -vendor-short-name }.
+    Mae'r rhyngwyneb hwn wedi'i gynllunio i'w ddefnyddio gan ddatblygwyr a phrofwyr <a data-l10n-name="fog-link">i brofi'r offeryniaeth</a> â llaw.
+about-glean-upload-enabled = Mae llwytho data i fyny wedi'i alluogi.
+about-glean-upload-disabled = Mae llwytho data i fyny wedi'i analluogi.
+about-glean-upload-enabled-local = Dim ond ar gyfer anfon i weinydd lleol y mae llwytho data i fyny wedi'i alluogi.
+about-glean-upload-fake-enabled =
+    Mae llwytho data i fyny wedi'i analluogi,
+    ond rydyn ni'n dweud celwydd ac yn dweud wrth y { glean-sdk-brand-name } ei fod wedi'i alluogi
+    fel bod data yn dal i gael ei gofnodi'n lleol.
+    Nodyn: Os ydych chi'n gosod tag dadfygio, bydd pingiau'n cael eu llwytho i fyny i'r
+    <a data-l10n-name="glean-debug-ping-viewer">{ glean-debug-ping-viewer-brand-name }</a> beth bynnag yw'r gosodiadau.
+# This message is followed by a bulleted list.
+about-glean-prefs-and-defines = Mae <a data-l10n-name="fog-prefs-and-defines-doc-link">dewisiadau a diffiniadau perthnasol</a> yn cynnwys:
+# Variables:
+#   $data-upload-pref-value (String): the value of the datareporting.healthreport.uploadEnabled pref. Typically "true", sometimes "false"
+# Do not translate strings between <code> </code> tags.
+about-glean-data-upload = <code>datareporting.healthreport.uploadEnabled</code>: { $data-upload-pref-value }
+# Variables:
+#   $local-port-pref-value (Integer): the value of the telemetry.fog.test.localhost_port pref. Typically 0. Can be negative.
+# Do not translate strings between <code> </code> tags.
+about-glean-local-port = <code>telemetry.fog.test.localhost_port</code>: { $local-port-pref-value }
+# Variables:
+#   $glean-android-define-value (Boolean): the value of the MOZ_GLEAN_ANDROID define. Typically "false", sometimes "true".
+# Do not translate strings between <code> </code> tags.
+about-glean-glean-android = <code>MOZ_GLEAN_ANDROID</code>: { $glean-android-define-value }
+# Variables:
+#   $moz-official-define-value (Boolean): the value of the MOZILLA_OFFICIAL define.
+# Do not translate strings between <code> </code> tags.
+about-glean-moz-official = <code>MOZILLA_OFFICIAL</code>: { $moz-official-define-value }
+about-glean-about-testing-header = Ynghylch Profi
+# This message is followed by a numbered list.
+about-glean-manual-testing =
+    Mae cyfarwyddiadau llawn wedi'u dogfennu yn y
+    <a data-l10n-name="fog-instrumentation-test-doc-link">{ -fog-brand-name } dogfennau profi'r offeryniaeth</a>
+    ac yn y <a data-l10n-name="glean-sdk-doc-link">{ glean-sdk-brand-name } ddogfennaeth</a>,
+    ond, yn fyr, i brofi â llaw bod eich offeryniaeth yn gweithio, dylech:
+# This message is an option in a dropdown filled with untranslated names of pings.
+about-glean-no-ping-label = (peidiwch â chyflwyno unrhyw pingiau)
+# An in-line text input field precedes this string.
+about-glean-label-for-tag-pings = Yn y maes blaenorol sicrhewch fod tag dadfygio cofiadwy fel y gallwch adnabod eich pingiau'n ddiweddarach.
+# An in-line text input field precedes this string.
+about-glean-label-for-tag-pings-with-requirements = Gosodwch dag dadfygio cofiadwy <span>(20 nod neu lai, alffaniwmerig a - yn unig)</span> er mwyn i chi allu adnabod eich pings yn nes ymlaen.
+# An in-line drop down list precedes this string.
+# Do not translate strings between <code> </code> tags.
+about-glean-label-for-ping-names =
+    Dewiswch o'r rhestr flaenorol y ping y mae eich offeryniaeth ynddo.
+    Os yw mewn <a data-l10n-name="custom-ping-link">custom-ping</a>, dewiswch yr un hwnnw.
+    Fel arall, y rhagosodiad ar gyfer metrigau <code>digwyddiad</code> yw
+    y  ping <code>digwyddiadau</code>
+    a'r rhagosodiad ar gyfer pob metrig arall yw
+    y ping <code>metrics</code>.
+# An in-line check box precedes this string.
+about-glean-label-for-log-pings =
+    (Dewisol. Ticiwch y blwch blaenorol os ydych am i pingiau gael eu cofnodi hefyd pan gânt eu cyflwyno.
+    Bydd angen i chi hefyd <a data-l10n-name="enable-logging-link">alluogi cofnodi</a>.)
+# Variables
+#   $debug-tag (String): The user-set value of the debug tag input on this page. Like "about-glean-kV"
+# An in-line button labeled "Apply settings and submit ping" precedes this string.
+about-glean-label-for-controls-submit =
+    Pwyswch y botwm blaenorol i dagio pob ping { -glean-brand-name } gyda'ch tag a chyflwynwch y ping a ddewiswyd.
+    (Bydd yr holl pingiau sy'n cael eu cyflwyno o hynny hyd nes y byddwch yn ailgychwyn y rhaglenyn cael eu tagio
+    <code>{ $debug-tag }</code>.)
+about-glean-li-for-visit-gdpv =
+    <a data-l10n-name="gdpv-tagged-pings-link">Ewch i dudalen { glean-debug-ping-viewer-brand-name } am bingiau gyda'ch tag</a>.
+    Dylai ddim cymryd mwy nag ychydig eiliadau o bwyso'r botwm i'ch ping gyrraedd.
+    Weithiau gall gymryd ychydig o funudau.
+# Do not translate strings between <code> </code> tags.
+about-glean-adhoc-explanation =
+    Am ragor o brofion <i>ad hoc</i>,
+    gallwch hefyd bennu gwerth cyfredol darn penodol o offeryniaeth
+    trwy agor consol devtools yma ar <code>about:glean</code>
+    a defnyddio'r API <code>testGetValue()</code> fel
+    <code>Glean.metricCategory.metricName.testGetValue()</code>.
+# Do not translate strings between <code> </code> tags.
+about-glean-adhoc-explanation2 =
+    Am ragor o brofion <i>ad hoc</i>,
+    gallwch hefyd bennu gwerth cyfredol darn penodol o offeryniaeth
+    trwy agor consol devtools yma ar <code>about:glean</code>
+    a defnyddio'r API <code>testGetValue()</code> fel
+    <code>Glean.metricCategory.metricName.testGetValue()</code>
+    ar gyfer metrig o'r enw <code>metric.category.metric_name</code>.
+# Do not translate strings between <code> </code> tags.
+about-glean-adhoc-note =
+    Sylwch eich bod yn defnyddio'r API Glean JS trwy ddefnyddio'r consol devtools.
+    Mae hyn yn golygu bod y categori metrig a'r enw metrig wedi'u fformatio
+    <code>camelCase</code> yn wahanol i'r APIs Rust a C++.
+controls-button-label-verbose = Gosod y gosodiadau ac anfon ping
+about-glean-about-data-header = Ynghylch Data
+about-glean-about-data-explanation =
+    I bori drwy'r rhestr o ddata a gasglwyd, edrychwch ar y
+    <a data-l10n-name="glean-dictionary-link"> { -glean-brand-name } Geiriadur</a>.
diff --git a/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl b/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl
new file mode 100644
index 0000000000..92c7ae6ff4
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutHttpsOnlyError.ftl
@@ -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/.
+
+about-httpsonly-title-alert = Rhybudd Modd HTTPS-yn-Unig
+about-httpsonly-title-site-not-available = Nid yw'r Safle 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-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 = Darllen Rhagor…
+
+## Suggestion Box that only shows up if a secure connection to www can be established
+## Variables:
+##   $websiteUrl (String) - Url of the website that can be securely loaded with these alternatives. Example: example.com
+
+about-httpsonly-suggestion-box-header = Dewisiadau Arall Posib
+about-httpsonly-suggestion-box-www-text = Mae fersiwn ddiogel o <em>www{ $websiteUrl }</em>. Gallwch ymweld â'r dudalen hon yn lle <em>{ $websiteUrl }</em>.
+about-httpsonly-suggestion-box-www-button = Mynd i www.{ $websiteUrl }
diff --git a/l10n-cy/toolkit/toolkit/about/aboutLogging.ftl b/l10n-cy/toolkit/toolkit/about/aboutLogging.ftl
new file mode 100644
index 0000000000..bbccf5aa6d
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutLogging.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 is the title of the page
+about-logging-title = Ynghylch Cofnodi
+about-logging-page-title = Logging manager
+about-logging-current-log-file = Ffeil Cofnodi Cyfredol:
+about-logging-new-log-file = Ffeil cofnod newydd:
+about-logging-currently-enabled-log-modules = Modiwlau cofnod wedi'u galluogi ar hyn o bryd:
+about-logging-log-tutorial = Gw <a data-l10n-name="logging">HTTP Logging</a> am wybodaeth ar sut i ddefnyddio'r teclyn hwn.
+# This message is used as a button label, "Open" indicates an action.
+about-logging-open-log-file-dir = Agor y cyfeiriadur
+about-logging-set-log-file = Gosod Ffeil Cofnodi
+about-logging-set-log-modules = Gosod Modiwlau Cofnodi
+about-logging-start-logging = Cychwyn Cofnodi
+about-logging-stop-logging = Peidio Cofnodi
+about-logging-buttons-disabled = Mae'r cofnodi wedi'i ffurfweddu trwy newidynnau amgylcheddol, nid yw ffurfweddu deinamig ar gael.
+about-logging-some-elements-disabled = Mae'r cofnodi wedi'i ffurfweddu trwy URL, nid oes rhai dewisiadau ffurfweddu ar gael
+about-logging-info = Gwybodaeth:
+about-logging-log-modules-selection = Dewisiadau modiwlau cofnodi
+about-logging-new-log-modules = Modiwlau cofnodi newydd:
+about-logging-logging-output-selection = Allbwn cofnodi
+about-logging-logging-to-file = Cofnodi i ffeil
+about-logging-logging-to-profiler = Cofnodi i { -profiler-brand-name }
+about-logging-no-log-modules = Dim
+about-logging-no-log-file = Dim
+about-logging-logging-preset-selector-text = Rhagosodiad cofnodi:
+about-logging-with-profiler-stacks-checkbox = Galluogi olion stac ar gyfer negeseuon cofnodion
+
+## Logging presets
+
+about-logging-preset-networking-label = Rhwydweithio
+about-logging-preset-networking-description = Cofnodi modiwlau er mwyn datrys materion rhwydweithio
+about-logging-preset-networking-cookie-label = Cwcis
+about-logging-preset-networking-cookie-description = Cofnodi modiwlau i wneud diagnosis o broblemau cwci
+about-logging-preset-networking-websocket-label = WebSockets
+about-logging-preset-networking-websocket-description = Cofnodi modiwlau er mwyn datrys materion WebSocket
+about-logging-preset-networking-http3-label = HTTP/3
+about-logging-preset-networking-http3-description = Cofnodi modiwlau er mwyn datrys materion HTTP/3 a QUIC
+about-logging-preset-networking-http3-upload-speed-label = Cyflymder llwytho HTTP/3
+about-logging-preset-networking-http3-upload-speed-description = Modiwlau cofnodi i wneud diagnosis o faterion cyflymder
+about-logging-preset-media-playback-label = Chwarae cyfryngau
+about-logging-preset-media-playback-description = Cofnodi modiwlau i ddatrys materion chwarae cyfryngau (nid materion fideo-gynadledda)
+about-logging-preset-webrtc-label = WebRTC
+about-logging-preset-webrtc-description = Cofnodi modiwlau er mwyn datrys materion galwadau WebRTC
+about-logging-preset-webgpu-label = WebGPU
+about-logging-preset-webgpu-description = Modiwlau cofnodi i wneud diagnosis o faterion WebGPU
+about-logging-preset-gfx-label = Graffigau
+about-logging-preset-gfx-description = Modiwlau cofnodi i wneud diagnosis o broblemau graffigau
+# This is specifically "Microsoft Windows". Microsoft normally doesn't localize it, and we should follow their convention here.
+about-logging-preset-windows-label = Windows
+about-logging-preset-windows-description = Cofnodi modiwlau i wneud diagnosis o faterion sy'n benodol i Microsoft Windows
+about-logging-preset-custom-label = Cyfaddas
+about-logging-preset-custom-description = Modiwlau cofnodion wedi'u dewis â llaw
+# Error handling
+about-logging-error = Gwall:
+
+## Variables:
+##   $k (String) - Variable name
+##   $v (String) - Variable value
+
+about-logging-invalid-output = Gwerth annilys “{ $v }“ ar gyfer allwedd “{ $k }“
+about-logging-unknown-logging-preset = Rhagosodiad cofnodi anhysbys “{ $v }“
+about-logging-unknown-profiler-preset = Rhagosodiad proffiliwr anhysbys “{ $v }“
+about-logging-unknown-option = Dewis about:logging anhysbys “{ $k }“
+about-logging-configuration-url-ignored = Anwybyddwyd URL ffurfweddiad
+about-logging-file-and-profiler-override = Methu â gorfodi allbwn ffeil a diystyru dewisiadau proffiliwr ar yr un pryd
+about-logging-configured-via-url = Dewis wedi'i ffurfweddu trwy URL
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..55d8054d96
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutNetworking.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/.
+
+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-trr-mode = Modd 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-type = Math
+about-networking-sent = Anfonwyd
+about-networking-received = Derbyniwyd
+about-networking-family = Teulu
+about-networking-trr = TRR
+about-networking-addresses = Cyfeiriadau
+about-networking-expires = Daw i ben (Eiliadau)
+about-networking-originAttributesSuffix = Allwedd Ynysu
+about-networking-flags = Baneri ychwanegol
+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-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 = 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
+# Note: do not translate about:logging, as it is a URL.
+about-networking-moved-about-logging = Mae'r dudalen hon wedi'i symud i <a data-l10n-name="about-logging-url">about:logging</a>.
+
+## 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..9743697b5d
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutPerformance.ftl
@@ -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/.
+
+# 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 occurred 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 occurred 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..5584a6a894
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutPlugins.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/.
+
+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">Darllen Rhagor.</a>
+deprecation-description2 =
+    .message = Colli rhywbeth? Nid yw rhai ategion yn cael eu cynnal.
+
+## 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
+
+## Gecko Media Plugins (GMPs)
+
+plugins-gmp-license-info = Manylion trwyddedu
+plugins-gmp-privacy-info = Manylion Preifatrwydd
+plugins-openh264-name = OpenH264 Video Codec wedi ei ddarparu gan Cisco Systems, Inc.
+plugins-openh264-description = 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 darllen rhagor am ei ddefnyddio.
+plugins-widevine-name = Mae'r Widevine Content Decryption Module wedi ei ddarparu gan Google Inc.
+plugins-widevine-description = 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.
diff --git a/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl b/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl
new file mode 100644
index 0000000000..2434f916a6
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutProcesses.ftl
@@ -0,0 +1,201 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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
+# Profiler icons
+# Variables:
+#    $duration (Number) The time in seconds during which the profiler will be running.
+#                       The value will be an integer, typically less than 10.
+about-processes-profile-process =
+    .title =
+        { $duration ->
+            [zero] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+            [one] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+            [two] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+            [few] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+            [many] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+           *[other] Proffilio'r holl edafedd y broses hon am { $duration } eiliad
+        }
+
+## 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.
+
+about-processes-browser-process = { -brand-short-name } ({ $pid })
+about-processes-web-process = Proses We a Rennir ({ $pid })
+about-processes-file-process = Ffeiliau ({ $pid })
+about-processes-extension-process = Estyniadau ({ $pid })
+about-processes-privilegedabout-process = Ynglŷn â thudalennau ({ $pid })
+about-processes-plugin-process = Ategion ({ $pid })
+about-processes-privilegedmozilla-process = Gwefannau { -vendor-short-name } ({ $pid })
+about-processes-gmp-plugin-process = Ategion Cyfryngau Gecko ({ $pid })
+about-processes-gpu-process = GPU ({ $pid })
+about-processes-vr-process = VR ({ $pid })
+about-processes-rdd-process = Datgodiwr Data ({ $pid })
+about-processes-socket-process = Rhwydwaith ({ $pid })
+about-processes-remote-sandbox-broker-process = Brocer Blwch Tywod Pell ({ $pid })
+about-processes-fork-server-process = Gweinydd Fforc ({ $pid })
+about-processes-preallocated-process = Wedi'i rhagddyrannu ({ $pid })
+about-processes-utility-process = Gwasanaeth ({ $pid })
+# Unknown process names
+# Variables:
+#    $pid (String) The process id of this process, assigned by the OS.
+#    $type (String) The raw type for this process.
+about-processes-unknown-process = Arall: { $type } ({ $pid })
+
+## Isolated process names
+## Variables:
+##    $pid (String) The process id of this process, assigned by the OS.
+##    $origin (String) The domain name for this process.
+
+about-processes-web-isolated-process = { $origin } ({ $pid })
+about-processes-web-serviceworker = { $origin } ({ $pid }, gweithiwr gwasanaeth)
+about-processes-with-coop-coep-process = { $origin } ({ $pid }, traws-darddiad ynysig)
+about-processes-web-isolated-process-private = { $origin } — Preifat ({ $pid })
+about-processes-with-coop-coep-process-private = { $origin } — Preifat ({ $pid }, traws-darddiad ynysig)
+
+## Details within processes
+
+# Single-line summary of threads (non-idle process)
+# 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.
+#    $active (Number) The number of active threads in the process.
+#                     The value will be greater than 0 and will never be
+#                     greater than $number.
+#    $list (String) Comma separated list of active threads.
+#                   Can be an empty string if the process is idle.
+about-processes-active-threads =
+    { $active ->
+        [zero] { $active } edafedd gweithredol allan o { $number }:{ $list }
+        [one] { $active } edafedd gweithredol allan o { $number }:{ $list }
+        [two] { $active } edafedd gweithredol allan o { $number }:{ $list }
+        [few] { $active } edafedd gweithredol allan o { $number }:{ $list }
+        [many] { $active } edafedd gweithredol allan o { $number }:{ $list }
+       *[other] { $active } edafedd gweithredol allan o { $number }:{ $list }
+    }
+# Single-line summary of threads (idle process)
+# 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.
+#                     The process is idle so all threads are inactive.
+about-processes-inactive-threads =
+    { $number ->
+        [zero] { $number } edafedd anweithredol
+        [one] { $number } edafedd anweithredol
+        [two] { $number } edafedd anweithredol
+        [few] { $number } edafedd anweithredol
+        [many] { $number } edafedd anweithredol
+       *[other] { $number } edafedd anweithredol
+    }
+# 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-and-id = { $name }
+    .title = ID edafedd: { $tid }
+# 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 }
+
+## Utility process actor names
+
+about-processes-utility-actor-unknown = Actor anhysbys
+about-processes-utility-actor-audio-decoder-generic = Datgodiwr Sain Generig
+about-processes-utility-actor-audio-decoder-applemedia = Datgodiwr Sain Apple Media
+about-processes-utility-actor-audio-decoder-wmf = Datgodiwr Sain Fframwaith Windows Media
+about-processes-utility-actor-mf-media-engine = CDM Media Engine Windows Media Foundation
+# "Oracle" refers to an internal Firefox process and should be kept in English
+about-processes-utility-actor-js-oracle = JavaScript Oracle
+about-processes-utility-actor-windows-utils = Windows Utils
+about-processes-utility-actor-windows-file-dialog = Deialog Ffeil Windows
+
+## 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 $total. See the definitions
+##                   of `duration-unit-*`.
+
+# Common case.
+about-processes-cpu = { NUMBER($percent, maximumSignificantDigits: 2, style: "percent") }
+    .title = Cyfanswm amser CPU: { NUMBER($total, maximumFractionDigits: 0) }{ $unit }
+# Special case: data is not available yet.
+about-processes-cpu-user-and-kernel-not-ready = (yn mesur)
+# Special case: process or thread is almost idle (using less than 0.1% of a CPU core).
+# This case only occurs on Windows where the precision of the CPU times is low.
+about-processes-cpu-almost-idle = <0.1%
+    .title = Cyfanswm amser CPU: { NUMBER($total, maximumFractionDigits: 0) }{ NUMBER($total, maximumFractionDigits: 0) }{ $unit }
+# Special case: process or thread is currently idle.
+about-processes-cpu-fully-idle = yn segur
+    .title = Cyfanswm amser CPU { NUMBER($total, maximumFractionDigits: 0) }{ NUMBER($total, maximumFractionDigits: 0) }{ $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 $delta. See the definitions
+##                        of `memory-unit-*`.
+
+# Common case.
+about-processes-total-memory-size-changed = { NUMBER($total, maximumFractionDigits: 0) }{ $totalUnit }
+    .title = Esblygiad: { $deltaSign }{ NUMBER($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/aboutReader.ftl b/l10n-cy/toolkit/toolkit/about/aboutReader.ftl
new file mode 100644
index 0000000000..400440656a
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutReader.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/.
+
+about-reader-loading = Yn llwytho…
+about-reader-load-error = Methwyd llwytho erthygl o dudalen
+
+about-reader-color-scheme-light = Golau
+    .title = Cynllun Lliw Golau
+about-reader-color-scheme-dark = Tywyll
+    .title = Cynllun Lliw Tywyll
+about-reader-color-scheme-sepia = Sepia
+    .title = Cynllun Lliw Sepia
+about-reader-color-scheme-auto = Awtomatig
+    .title = Cynllun Lliw Awtomatig
+
+# An estimate for how long it takes to read an article,
+# expressed as a range covering both slow and fast readers.
+# Variables:
+#   $rangePlural (String): The plural category of the range, using the same set as for numbers.
+#   $range (String): The range of minutes as a localised string. Examples: "3-7", "~1".
+about-reader-estimated-read-time =
+    { $rangePlural ->
+        [zero] Dim munudau
+        [one] { $range } munud
+        [two] { $range } munud
+        [few] { $range } munud
+        [many] { $range } munud
+       *[other] { $range } munud
+    }
+
+## These are used as tooltips in Type Control
+
+about-reader-toolbar-minus =
+    .title = Lleihau Maint Testun
+about-reader-toolbar-plus =
+    .title = Cynyddu Maint Testun
+about-reader-toolbar-contentwidthminus =
+    .title = Lleihau Lled Cynnwys
+about-reader-toolbar-contentwidthplus =
+    .title = Cynyddu Lled Cynnwys
+about-reader-toolbar-lineheightminus =
+    .title = Lleihau Uchder Llinell
+about-reader-toolbar-lineheightplus =
+    .title = Cynyddu Uchder Llinell
+
+## These are the styles of typeface that are options in the reader view controls.
+
+about-reader-font-type-serif = Serif
+about-reader-font-type-sans-serif = Sans-serif
+
+## Reader View toolbar buttons
+
+about-reader-toolbar-close = Cau'r Golwg Darllen
+about-reader-toolbar-type-controls = Rheoli'r math
+about-reader-toolbar-savetopocket = Cadw i { -pocket-brand-name }
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..537d0d4114
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutSupport.ftl
@@ -0,0 +1,446 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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 = Adroddiadau 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.
+support-addons-title = Ychwanegion
+support-addons-name = Enw
+support-addons-type = Math
+support-addons-enabled = Galluogwyd
+support-addons-version = Fersiwn
+support-addons-id = ID
+legacy-user-stylesheets-title = Hen Ddalenni Arddull Defnyddiwr
+legacy-user-stylesheets-enabled = Gweithredol
+legacy-user-stylesheets-stylesheet-types = Dalenni arddull
+legacy-user-stylesheets-no-stylesheets-found = Heb ganfod dalenni arddull
+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'r 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
+app-basics-os-theme = Thema OS
+# 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-third-party = Modiwlau Trydydd Parti
+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
+app-basics-memory-size = Maint Cof (RAM)
+app-basics-disk-available = Lle ar Ddisg ar Gael
+app-basics-pointing-devices = Dyfeisiau Pwyntio
+# Variables:
+#   $value (number) - Amount of data being stored
+#   $unit (string) - The unit of data being stored (e.g. MB)
+app-basics-data-size = { $value } { $unit }
+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
+graphics-device-pixel-ratios = Cymarebau Picsel Dyfais Ffenestr
+# 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-stats = Ystadegau
+place-database-stats-show = Dangos Ystadegau
+place-database-stats-hide = Cuddio Ystadegau
+place-database-stats-entity = Endid
+place-database-stats-count = Cyfrif
+place-database-stats-size-kib = Maint (KiB)
+place-database-stats-size-perc = Maint (%)
+place-database-stats-efficiency-perc = Effeithlonrwydd (%)
+place-database-stats-sequentiality-perc = Dilynianedd (%)
+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
+troubleshoot-mode-title = Datrys materion
+restart-in-troubleshoot-mode-label = Y Modd Datrys Problemau…
+clear-startup-cache-title = Ceisiwch glirio'r storfa gychwyn
+clear-startup-cache-label = Clirio'r storfa gychwyn…
+startup-cache-dialog-title2 = Ailgychwyn { -brand-short-name } i glirio'r storfa cychwyn?
+startup-cache-dialog-body2 = Ni fydd hyn yn newid eich gosodiadau nac yn dileu estyniadau.
+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
+media-codec-support-info = Gwybodaeth Gymorth Codec
+# List all the entries of the database.
+media-capabilities-enumerate = Cyfrifo'r gronfa ddata
+
+## Codec support table
+
+media-codec-support-sw-decoding = Datgodio Meddalwedd
+media-codec-support-hw-decoding = Datgodio Caledwedd
+media-codec-support-codec-name = Enw Codec
+media-codec-support-supported = Cefnogaeth
+media-codec-support-unsupported = Heb eu Cynnal
+media-codec-support-error = Nid yw manylion cymorth codec ar gael. Ceisiwch eto ar ôl chwarae ffeil cyfryngau.
+media-codec-support-lack-of-extension = Gosod estyniad
+
+## Media Content Decryption Modules (CDM)
+## See EME Spec for more explanation for following technical terms
+## https://w3c.github.io/encrypted-media/
+
+media-content-decryption-modules-title = Manylion Modiwlau Dadgryptio Cynnwys
+media-key-system-name = Enw System Allwedd
+media-video-robustness = Cadernid Fideo
+media-audio-robustness = Cadernid Sain
+media-cdm-capabilities = Galluoedd
+# Clear Lead isn't defined in the spec, which means the the first few seconds
+# are not encrypted. It allows playback to start without having to wait for
+# license response, improving video start time and user experience.
+media-cdm-clear-lead = Cychwyn Clir (Clear Lead)
+
+##
+
+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
+
+##
+
+# 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
+webgpu-default-adapter = Addasydd Rhagosodedig WebGPU
+webgpu-fallback-adapter = Addasydd wrth Gefn WebGPU
+# 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
+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
+content-win32k-lockdown-state = Cyflwr Clo Win32k ar gyfer y Broses Cynnwys
+support-sandbox-gpu-level = Lefel Blwch Tywod Proses GPU
+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 }
+# 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-env = Analluogwyd gan yr amgylchedd
+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
+fission-status-enabled-by-rollout = Wedi'i alluogi trwy ei gyflwyno fesul cam
+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
+
+## Normandy sections
+
+support-remote-experiments-title = Arbrofion Pell
+support-remote-experiments-name = Enw
+support-remote-experiments-branch = Cangen Arbrofi
+support-remote-experiments-see-about-studies = Gweler <a data-l10n-name="support-about-studies-link">about:studies</a> i gael mwy o wybodaeth, gan gynnwys sut i analluogi arbrofion unigol neu i analluogi { -brand-short-name } rhag rhedeg y math yma o arbrawf yn y dyfodol.
+support-remote-features-title = Nodweddion Pell
+support-remote-features-name = Enw
+support-remote-features-status = Statws
+
+## Pointing devices
+
+pointing-device-mouse = Llygoden
+pointing-device-touchscreen = Sgrin Cyffwrdd
+pointing-device-pen-digitizer = Digidydd Pen
+pointing-device-none = Dim dyfeisiau pwyntio
diff --git a/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl b/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl
new file mode 100644
index 0000000000..6a529c3261
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutTelemetry.ftl
@@ -0,0 +1,140 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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-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 (number) - Amount of histogram samples
+#   $prettyAverage (number) - Average of histogram samples
+#   $sum (number) - 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 = y cyfan
+# 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:
+#   $lateWriteCount (number) - 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
+# 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/aboutThirdParty.ftl b/l10n-cy/toolkit/toolkit/about/aboutThirdParty.ftl
new file mode 100644
index 0000000000..cb36ff8dd8
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutThirdParty.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/.
+
+third-party-page-title = Gwybodaeth am Fodiwlau Trydydd Parti
+third-party-section-title = Rhestr o fodiwlau trydydd parti yn { -brand-short-name }
+third-party-intro =
+    Mae'r dudalen hon yn dangos y modiwlau trydydd parti a chwistrellwyd i'ch { -brand-short-name }.
+    Mae unrhyw fodiwl sydd heb ei lofnodi gan Microsoft neu { -vendor-short-name } 
+    yn cael ei ystyried yn fodiwl trydydd parti.
+third-party-message-empty = Heb ganfod unrhyw fodiwlau trydydd parti.
+third-party-message-no-duration = Heb ei recordio
+third-party-detail-version = Fersiwn ffeil
+third-party-detail-vendor = Manylion y gwerthwr
+third-party-detail-occurrences = Amlder
+    .title = Sawl gwaith mae'r modiwl hwn wedi'i lwytho
+third-party-detail-duration = Cyfartaledd amser Rhwystro (ms)
+    .title = Am faint o amser rhwystrodd y modiwl y rhaglen.
+third-party-detail-app = Rhaglen
+third-party-detail-publisher = Cyhoeddwr
+third-party-th-process = Proses
+third-party-th-duration = Cyfnod Llwytho (ms)
+third-party-th-status = Statws
+third-party-tag-ime = IME
+    .title = Mae'r math yma o fodiwl wedi ei lwytho pan fyddwch yn defnyddio IME trydydd parti.
+third-party-tag-shellex = Estyniad Cragen
+    .title = Mae'r math yma o fodiwl wedi ei lwytho pan fyddwch yn agor deialog ffeil y system.
+third-party-tag-background = Cefndir
+    .title =
+        Nid yw'r modiwl yn rhwystro'r rhaglen am ei fod wedi
+        ei lwytho yn y cefndir.
+third-party-icon-unsigned =
+    .title = Nid yw'r modiwl hwn wedi'i lofnodi
+    .alt = Nid yw'r modiwl hwn wedi'i lofnodi
+third-party-icon-warning =
+    .title = Chwalodd { -brand-short-name } yn y cod o'r modiwl hwn
+    .alt = Chwalodd { -brand-short-name } yn y cod o'r modiwl hwn
+third-party-status-loaded = Wedi llwytho
+third-party-status-blocked = Rhwystrwyd
+third-party-status-redirected = Wedi'i ailgyfeirio
+third-party-button-copy-to-clipboard = Copïo data bras i'r clipfwrdd
+third-party-loading-data =
+    .alt = Yn llwytho gwybodaeth system…
+    .title = Yn llwytho gwybodaeth system…
+third-party-button-reload = Ail-lwytho gyda manylion y system
+    .title = Ail-lwytho gyda manylion y system
+third-party-button-open =
+    .title = Agor lleoliad ffeil…
+third-party-button-to-block =
+    .title = Rhwystro'r modiwl hwn
+    .aria-label = Rhwystro'r modiwl hwn
+third-party-button-to-unblock =
+    .title = Wedi'i rwystro ar hyn o bryd. Cliciwch i'w ddadrwystro.
+    .aria-label = Wedi'i rwystro ar hyn o bryd. Cliciwch i'w ddadrwystro.
+third-party-button-to-unblock-disabled =
+    .title =
+        Wedi'i nodi fel wedi'i rwystro ar hyn o bryd, er bod y rhestr rhwystro wedi'i hanalluogi ar gyfer y rhediad hwn
+        o { -brand-short-name }. Cliciwch i'w ddadrwystro.
+    .aria-label =
+        Wedi'i nodi fel wedi'i rwystro ar hyn o bryd, er bod y rhestr rhwystro wedi'i hanalluogi ar gyfer y rhediad hwn
+        o { -brand-short-name }. Cliciwch i'w ddadrwystro.
+third-party-button-to-block-module = Rhwystro'r modiwl hwn
+    .title = Rhwystro'r modiwl hwn
+    .aria-label = Rhwystro'r modiwl hwn
+third-party-button-to-unblock-module = Dadrwystro'r modiwl hwn
+    .title = Wedi'i rwystro. Cliciwch i'w ddadrwystro.
+    .aria-label = Wedi'i rwystro. Cliciwch i'w ddadrwystro.
+third-party-button-to-unblock-module-disabled = Dadrwystro'r modiwl hwn (rhestr rhwystro wedi'i analluogi)
+    .title =
+        Wedi'i nodi fel wedi'i rwystro, er fod y rhestr rhwystro wedi ei analluogi ar gyfer y rhediad yma
+        o { -brand-short-name }. Cliciwch i'w ddadrwystro.
+    .aria-label =
+        Wedi'i nodi fel wedi'i rwystro, er fod y rhestr rhwystro wedi ei analluogi ar gyfer y rhediad yma
+        o { -brand-short-name }. Cliciwch i'w ddadrwystro.
+third-party-button-expand =
+    .title = Dangos gwybodaeth fanwl
+third-party-button-collapse =
+    .title = Cau gwybodaeth fanwl
+third-party-blocking-requires-restart = I rwystro modiwl trydydd parti, rhaid i { -brand-short-name } ailgychwyn.
+third-party-should-restart-title = Ailgychwyn { -brand-short-name }
+third-party-restart-now = Ailgychwyn nawr
+third-party-restart-later = Ailgychwyn yn ddiweddarach
+third-party-blocked-by-builtin =
+    .title = Wedi'i rwystro gan { -brand-short-name }
+    .alt = Wedi'i rwystro gan { -brand-short-name }
diff --git a/l10n-cy/toolkit/toolkit/about/aboutWebauthn.ftl b/l10n-cy/toolkit/toolkit/about/aboutWebauthn.ftl
new file mode 100644
index 0000000000..1b94b63275
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutWebauthn.ftl
@@ -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/.
+
+
+### Localization for about:webauthn, a security token management page
+
+# Page title
+# 'WebAuthn' is a protocol name and should not be translated
+about-webauthn-page-title = Ynghylch WebAuthn
+
+## Section titles
+
+about-webauthn-info-section-title = Manylion dyfais
+about-webauthn-info-subsection-title = Manylion dilysydd
+about-webauthn-options-subsection-title = Dewisiadau dilysydd
+about-webauthn-pin-section-title = Rheoli PIN
+about-webauthn-credential-management-section-title = Rheoli manylion
+about-webauthn-pin-required-section-title = Mae angen PIN
+about-webauthn-confirm-deletion-section-title = Cadarnhau dileu
+
+## Info field texts
+
+about-webauthn-text-connect-device = Cysylltwch docyn diogelwch.
+# If multiple devices are plugged in, they will blink and we are asking the user to select one by touching the device they want.
+about-webauthn-text-select-device = Dewiswch eich tocyn diogelwch o'ch dewis trwy gyffwrdd â'r ddyfais.
+# CTAP2 refers to Client to Authenticator Protocol version 2
+about-webauthn-text-non-ctap2-device = Methu â rheoli'r dewisiadau oherwydd nad yw eich tocyn diogelwch yn cefnogi CTAP2.
+about-webauthn-text-not-available = Nid yw ar gael ar y platfform hwn.
+
+## Results label
+
+about-webauthn-results-success = Llwyddiant!
+about-webauthn-results-general-error = Gwall!
+# Variables:
+#  $retriesLeft (Number): number of tries left
+about-webauthn-results-pin-invalid-error =
+    { $retriesLeft ->
+        [0] Gwall: PIN anghywir. Ceisiwch eto.
+        [zero] Gwall: PIN anghywir. Ceisiwch eto. Nid oes gennych unrhyw geisiadau ar ôl.
+        [one] Gwall: PIN anghywir. Ceisiwch eto. Mae gennych un cais ar ôl.
+        [two] Gwall: PIN anghywir. Ceisiwch eto. Mae gennych { $retriesLeft } gais ar ôl.
+        [few] Gwall: PIN anghywir. Ceisiwch eto. Mae gennych { $retriesLeft } chais ar ôl.
+        [many] Gwall: PIN anghywir. Ceisiwch eto. Mae gennych { $retriesLeft } chais ar ôl.
+       *[other] Gwall: PIN anghywir. Ceisiwch eto. Mae gennych { $retriesLeft } cais ar ôl.
+    }
+about-webauthn-results-pin-blocked-error = Gwall: Nid oes unrhyw geisiadau ar ôl ac mae'ch dyfais wedi'i chloi, oherwydd cyflwynwyd y PIN anghywir gormod o weithiau. Mae angen ailosod y ddyfais.
+about-webauthn-results-pin-too-short-error = Gwall: Mae'r PIN hwn yn rhy fyr.
+about-webauthn-results-pin-too-long-error = Gwall: Mae'r PIN hwn yn rhy hir.
+about-webauthn-results-pin-auth-blocked-error = Gwall: Bu gormod o geisiadau wedi methu yn olynol ac mae dilysu PIN wedi'i rwystro dros dro. Mae angen cylchred pŵer ar eich dyfais (dad-blygio ac ail-blygio).
+about-webauthn-results-cancelled-by-user-error = Gwall: Mae'r gweithrediad wedi'i ddiddymu gan y defnyddiwr.
+
+## Labels
+
+about-webauthn-new-pin-label = PIN newydd:
+about-webauthn-repeat-pin-label = Ailadrodd PIN newydd:
+about-webauthn-current-pin-label = Y PIN cyfredol:
+about-webauthn-pin-required-label = Rhowch eich PIN:
+about-webauthn-credential-list-subsection-title = Manylion:
+about-webauthn-credential-list-empty = Dim manylion adnabod ar y ddyfais.
+about-webauthn-confirm-deletion-label = Rydych ar fin dileu:
+
+## Buttons
+
+about-webauthn-current-set-pin-button = Gosod PIN
+about-webauthn-current-change-pin-button = Newid PIN
+# List is a verb, as in "Show list of credentials"
+about-webauthn-list-credentials-button = Rhestru'r manylion personol
+about-webauthn-cancel-button = Diddymu
+about-webauthn-send-pin-button = Iawn
+about-webauthn-delete-button = Dileu
+
+## Authenticator options fields
+## Option fields correspond to the CTAP2 option IDs and definitions found in https://fidoalliance.org/specs/fido-v2.1-ps-20210615/fido-client-to-authenticator-protocol-v2.1-ps-20210615.html#option-id
+
+about-webauthn-auth-option-uv = Dilysiad defnyddiwr
+about-webauthn-auth-option-up = Presenoldeb defnyddiwr
+about-webauthn-auth-option-clientpin = PIN cleient
+about-webauthn-auth-option-rk = Allwedd preswylydd
+about-webauthn-auth-option-plat = Dyfais platfform
+# pinUvAuthToken should not be translated.
+about-webauthn-auth-option-pinuvauthtoken = Caniatâd gorchymyn (pinUvAuthToken)
+# MakeCredential and GetAssertion should not be translated.
+about-webauthn-auth-option-nomcgapermissionswithclientpin = Dim caniatâd MakeCredential / GetAssertion gyda'r PIN cleient
+about-webauthn-auth-option-largeblobs = Blobs mawr
+about-webauthn-auth-option-ep = Ardystiad menter
+about-webauthn-auth-option-bioenroll = Cofrestriad biometrig
+# FIDO_2_1_PRE should not be translated.
+about-webauthn-auth-option-userverificationmgmtpreview = Prototeip o gofrestriad biometrig (FIDO_2_1_PRE)
+about-webauthn-auth-option-uvbioenroll = Caniatâd cofrestriad biometrig
+about-webauthn-auth-option-authnrcfg = Ffurfweddiad y dilysydd
+about-webauthn-auth-option-uvacfg = Caniatâd ffurfweddiad y dilysydd
+about-webauthn-auth-option-credmgmt = Rheoli manylion personol
+about-webauthn-auth-option-credentialmgmtpreview = Rheoli manylion personol prototeip
+about-webauthn-auth-option-setminpinlength = Gosod isafswm hyd PIN
+# MakeCredential should not be translated.
+about-webauthn-auth-option-makecreduvnotrqd = MakeCredential heb ddilysiad defnyddiwr
+about-webauthn-auth-option-alwaysuv = Angen gwirio defnyddiwr bob tro
+# Shows when boolean value for an option is True. True should not be translated.
+about-webauthn-auth-option-true = True
+# Shows when boolean value of an option is False. False should not be translated.
+about-webauthn-auth-option-false = False
+# If the value is missing (null), it means a certain feature is not supported.
+about-webauthn-auth-option-null = Heb ei gefnogi
+
+## Authenticator info fields
+## Info fields correspond to the CTAP2 authenticatorGetInfo field member name and definitions found in https://fidoalliance.org/specs/fido-v2.1-ps-20210615/fido-client-to-authenticator-protocol-v2.1-ps-20210615.html#authenticatorGetInfo
+
+about-webauthn-auth-info-vendor-prototype-config-commands = Gorchmynion ffurfweddu prototeip y gwerthwr
+about-webauthn-auth-info-remaining-discoverable-credentials = Manylion personol darganfyddadwy sy'n weddill
+about-webauthn-auth-info-certifications = Ardystiadau
+about-webauthn-auth-info-uv-modality = Moddion dilysu defnyddwyr
+about-webauthn-auth-info-preferred-platform-uv-attempts = Ymdrechion dilysu dewis platfform y defnyddiwr
+about-webauthn-auth-info-max-rpids-for-set-min-pin-length = IDau partïon mwyaf ar gyfer isafswm hyd PIN penodol
+about-webauthn-auth-info-max-cred-blob-length = Uchafswm hyd blob manylion personol
+about-webauthn-auth-info-firmware-version = Fersiwn cadarnwedd
+about-webauthn-auth-info-min-pin-length = Hyd lleiaf PIN
+about-webauthn-auth-info-force-pin-change = Gorfodi newid PIN
+about-webauthn-auth-info-max-ser-large-blob-array = Maint mwyaf arae blob mawr
+about-webauthn-auth-info-algorithms = Algorithmau
+about-webauthn-auth-info-transports = Cludiant
+about-webauthn-auth-info-max-credential-id-length = Uchafswm hyd ID manylion personol
+about-webauthn-auth-info-max-credential-count-in-list = Uchafswm y cyfrif manylion personol yn y rhestr
+about-webauthn-auth-info-pin-protocols = Protocolau PINiau
+about-webauthn-auth-info-max-msg-size = Uchafswm maint y neges
+# AAGUID should not be translated.
+about-webauthn-auth-info-aaguid = AAGUID
+about-webauthn-auth-info-extensions = Estyniadau
+about-webauthn-auth-info-versions = Fersiynau
+# Shows when boolean value for an info field is True. True should not be translated.
+about-webauthn-auth-info-true = True
+# Shows when boolean value for an info field is False. False should not be translated.
+about-webauthn-auth-info-false = False
+about-webauthn-auth-info-null = Heb ei gefnogi
diff --git a/l10n-cy/toolkit/toolkit/about/aboutWebrtc.ftl b/l10n-cy/toolkit/toolkit/about/aboutWebrtc.ftl
new file mode 100644
index 0000000000..24d40a8959
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutWebrtc.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/.
+
+
+### 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
+
+## These labels are for a disclosure which contains the information for closed PeerConnection sections
+
+about-webrtc-closed-peerconnection-disclosure-show-msg = Dangos PeerConnections Caeedig
+about-webrtc-closed-peerconnection-disclosure-hide-msg = Cuddio PeerConnections Caeedig
+
+## 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)
+about-webrtc-aec-logging-toggled-on-state-msg = Cofnodi AEC yn weithredol (siarad gyda'r galwr am ychydig funudau ac yna atal y cipio)
+about-webrtc-aec-logging-unavailable-sandbox = Mae angen y newidyn amgylchedd MOZ_DISABLE_CONTENT_SANDBOX=1 er mwyn allforio cofnodion AEC. Gosodwch y newidyn hwn dim ond os ydych chi'n deall y risgiau posibl.
+# Variables:
+#  $path (String) - The path to which the aec log file is saved.
+about-webrtc-aec-logging-toggled-off-state-msg = Mae'r ffeiliau cofnod y cipio yn: { $path }
+
+##
+
+# The autorefresh checkbox causes a stats section to autorefresh its content when checked
+about-webrtc-auto-refresh-label = Auto Adnewyddu
+# Determines the default state of the Auto Refresh check boxes
+about-webrtc-auto-refresh-default-label = Awto Adnewyddu Rhagosodedig
+# A button which forces a refresh of displayed statistics
+about-webrtc-force-refresh-button = Adnewyddu
+# "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:
+# The number of DataChannels that a PeerConnection has opened
+about-webrtc-data-channels-opened-label = Sianeli Data Agorwyd:
+# The number of once open DataChannels that a PeerConnection has closed
+about-webrtc-data-channels-closed-label = Sianeli Data Caewyd:
+
+## "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
+
+## 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-enable-logging-label = Galluogi Rhagosodiad Cofnod WebRTC
+about-webrtc-stats-heading = Ystadegau'r Sesiwn
+about-webrtc-peerconnections-section-heading = Ystadegau RTCPeerConnection
+about-webrtc-peerconnections-section-show-msg = Dangos Ystadegau RTCPeerConnection
+about-webrtc-peerconnections-section-hide-msg = Cuddio Ystadegau RTCPeerConnection
+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
+about-webrtc-log-section-show-msg = Dangos cofnod
+    .title = Cliciwch i ehangu'r adran
+about-webrtc-log-section-hide-msg = Cuddio cofnod
+    .title = Cliciwch i gau'r adran
+about-webrtc-copy-report-button = Copïo Adroddiad
+about-webrtc-copy-report-history-button = Copïo Hanes Adroddiad
+
+## 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 }
+
+## These are used to indicate what direction media is flowing.
+## Variables:
+##  $codecs - a list of media codecs
+
+about-webrtc-short-send-receive-direction = Anfon / Derbyn: { $codecs }
+about-webrtc-short-send-direction = Anfon: { $codecs }
+about-webrtc-short-receive-direction = Derbyn: { $codecs }
+
+##
+
+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-raw-cand-section-show-msg = Dangos ymgeiswyr bras
+    .title = Cliciwch i ehangu'r adran
+about-webrtc-raw-cand-section-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-fold-default-show-msg = Dangos manylion
+    .title = Cliciwch i ehangu'r adran
+about-webrtc-fold-default-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-current-framerate-label = Cyfradd fframio
+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
+
+## These are displayed on the button that shows or hides the
+## PeerConnection configuration disclosure
+
+about-webrtc-pc-configuration-show-msg = Dangos Ffurfweddiad
+about-webrtc-pc-configuration-hide-msg = Cuddio Ffurfwedd
+
+##
+
+# 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
+# The options set by the user in about:config that could impact a WebRTC call
+about-webrtc-user-modified-configuration-heading = Ffurfweddiad WebRTC wedi'i Addasu gan Ddefnyddiwr
+
+## These are displayed on the button that shows or hides the
+## user modified configuration disclosure
+
+about-webrtc-user-modified-configuration-show-msg = Dangos Ffurfweddiad Defnyddiwr Wedi'i Addasu
+about-webrtc-user-modified-configuration-hide-msg = Cuddio Ffurfweddiad Defnyddiwr Wedi'i Addasu
+
+##
+
+# 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 path is used for saving the about:webrtc page so it can be attached to
+# bug reports.
+# Variables:
+#  $path (String) - The path to which the file is saved.
+about-webrtc-save-page-complete-msg = Cadwyd y dudalen i: { $path }
+# This is the total number of frames encoded or decoded over an RTP stream.
+# Variables:
+#  $frames (Number) - The number of frames encoded or decoded.
+about-webrtc-frames =
+    { $frames ->
+        [zero] { $frames } fframiau
+        [one] { $frames } ffrâm
+        [two] { $frames } ffrâm
+        [few] { $frames } ffrâm
+        [many] { $frames } ffrâm
+       *[other] { $frames } ffrâm
+    }
+# This is the number of audio channels encoded or decoded over an RTP stream.
+# Variables:
+#  $channels (Number) - The number of channels encoded or decoded.
+about-webrtc-channels =
+    { $channels ->
+        [zero] { $channels } sianeli
+        [one] { $channels } sianel
+        [two] { $channels } sianel
+        [few] { $channels } sianel
+        [many] { $channels } sianel
+       *[other] { $channels } sianel
+    }
+# 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)
+
+## These are displayed on the button that shows or hides the SDP information disclosure
+
+about-webrtc-show-msg-sdp = Dangos SDP
+about-webrtc-hide-msg-sdp = Cuddio SDP
+
+## These are displayed on the button that shows or hides the Media Context information disclosure.
+## The Media Context is the set of preferences and detected capabilities that informs
+## the negotiated CODEC settings.
+
+about-webrtc-media-context-show-msg = Dangos Cyd-destun Cyfryngau
+about-webrtc-media-context-hide-msg = Cuddio Cyd-destun Cyfryngau
+about-webrtc-media-context-heading = Cyd-destun Cyfryngau
+
+##
+
diff --git a/l10n-cy/toolkit/toolkit/about/aboutWindowsMessages.ftl b/l10n-cy/toolkit/toolkit/about/aboutWindowsMessages.ftl
new file mode 100644
index 0000000000..772ba35c64
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/aboutWindowsMessages.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/.
+
+
+### Localization for the about:windows-messages page, which is only available
+### on the Windows operating system.
+### This page records and shows messages sent from the operating system to
+### individual browser windows. These messages can be useful in debugging
+### hard-to-reproduce issues with window sizing and position.
+
+# Windows refers to the operating system
+windows-messages-page-title = Manylion Negeseuon Windows
+windows-messages-intro =
+    Mae'r dudalen hon yn dangos y negeseuon mwyaf diweddar
+    a anfonwyd gan Windows i ffenestri porwr { -brand-short-name }.
+    Mae'r mae cofnod trwm yn cynrychioli'r ffenestr hon. Sylwch fod
+    y dudalen hon yn dangos y negeseuon mwyaf diweddar ar yr adeg
+    y llwythwyd y dudalen; i weld y rhai cyfredol bydd angen i chi
+    adnewyddu'r dudalen.
+windows-messages-copy-to-clipboard = Copïo i'r clipfwrdd
diff --git a/l10n-cy/toolkit/toolkit/about/abuseReports.ftl b/l10n-cy/toolkit/toolkit/about/abuseReports.ftl
new file mode 100644
index 0000000000..e97e394451
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/abuseReports.ftl
@@ -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/.
+
+# Localized string used as the dialog window title.
+# "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-sitepermission = Adroddwch ychwanegyn Caniatâd y Wefan hon 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-learnmore-intro = Ddim yn siŵr pa fater i'w ddewis?
+abuse-report-learnmore-link = Dysgwch fwy am adrodd ar estyniadau a themâu
+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-sitepermission = Diolch 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.
+abuse-report-messagebar-aborted2 =
+    .message = Diddymwyd yr adroddiad ar gyfer { $addon-name }>.
+abuse-report-messagebar-submitting2 =
+    .message = Anfon adroddiad ar gyfer { $addon-name }.
+abuse-report-messagebar-submitted2 =
+    .message = Diolch i chi am gyflwyno adroddiad. Ydych chi am gael gwared ar { $addon-name }?
+abuse-report-messagebar-submitted-noremove2 =
+    .message = Diolch am gyflwyno adroddiad.
+abuse-report-messagebar-removed-extension2 =
+    .message = Diolch i chi am gyflwyno adroddiad. Rydych wedi tynnu'r estyniad { $addon-name }.
+abuse-report-messagebar-removed-sitepermission2 =
+    .message = Diolch am gyflwyno adroddiad. Rydych wedi tynnu'r estyniad { $addon-name }
+abuse-report-messagebar-removed-theme2 =
+    .message = Diolch i chi am gyflwyno adroddiad. Rydych chi wedi tynnu'r thema { $addon-name }
+abuse-report-messagebar-error2 =
+    .message = Roedd gwall wrth anfon yr adroddiad ar gyfer { $addon-name }.
+abuse-report-messagebar-error-recent-submit2 =
+    .message = Nid yw'r adroddiad ar gyfer { $addon-name } 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-sitepermission = Iawn, Dileu
+abuse-report-messagebar-action-keep-sitepermission = 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 cartref 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-sitepermission-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-sitepermission =
+    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 wefan.
+    <a data-l10n-name="support-link">Ewch i'r wefan</a> i gael manylion 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..5185734a82
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/certviewer.ftl
@@ -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/.
+
+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 = Bysbrintiau
+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..7c040f4cd4
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/config.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/.
+
+
+## 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..e48a4e996f
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/about/url-classifier.ftl
@@ -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/.
+
+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
+
+## Variables
+##   $error (string) - Error message
+
+url-classifier-update-error = gwall diweddaru ({ $error })
+url-classifier-download-error = gwall llwytho i lawr ({ $error })
diff --git a/l10n-cy/toolkit/toolkit/branding/accounts.ftl b/l10n-cy/toolkit/toolkit/branding/accounts.ftl
new file mode 100644
index 0000000000..1dc6d58608
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/branding/accounts.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/.
+
+# “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/toolkit/toolkit/branding/brandings.ftl b/l10n-cy/toolkit/toolkit/branding/brandings.ftl
new file mode 100644
index 0000000000..af0f8b32fd
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/branding/brandings.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/.
+
+
+## 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
+-translations-brand-name = Firefox Translations
+-focus-brand-name = Firefox Focus
+-relay-brand-name = Firefox Relay
+-relay-brand-short-name = Relay
+-fakespot-brand-name = Fakespot
+# Note the name of the website is capitalized.
+-fakespot-website-name = Fakespot.com
+# The particle "by" can be localized, "Fakespot" and "Mozilla" should not be localized or transliterated.
+-fakespot-brand-full-name = Fakespot gan Mozilla
+# “Suggest” can be localized, “Firefox” must be treated as a brand
+# and kept in English.
+-firefox-suggest-brand-name = Awgrymadau Firefox
+# ”Home" can be localized, “Firefox” must be treated as a brand
+# and kept in English.
+-firefox-home-brand-name = Cartref Firefox
+# View" can be localized, “Firefox” must be treated as a brand
+# and kept in English.
+-firefoxview-brand-name = Cipolwg Firefox
diff --git a/l10n-cy/toolkit/toolkit/contentanalysis/contentanalysis.ftl b/l10n-cy/toolkit/toolkit/contentanalysis/contentanalysis.ftl
new file mode 100644
index 0000000000..3a048e17d4
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/contentanalysis/contentanalysis.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/.
+
+contentanalysis-alert-title = Dadansoddi Cynnwys
+# Variables:
+#   $content - Description of the content being warned about, such as "clipboard" or "aFile.txt"
+contentanalysis-slow-agent-notification = Mae'r teclyn Dadansoddi Cynnwys yn cymryd amser hir i ymateb ynghylch adnodd “{ $content }”
+contentanalysis-slow-agent-dialog-title = Wrthi'n dadansoddi cynnwys
+# Variables:
+#   $content - Description of the content being warned about, such as "clipboard" or "aFile.txt"
+contentanalysis-slow-agent-dialog-body = Mae Dadansoddi Cynnwys yn dadansoddi adnodd “{ $content }”
+contentanalysis-operationtype-clipboard = clipfwrdd
+contentanalysis-operationtype-dropped-text = testun wedi'i ostwng
+contentanalysis-warndialogtitle = Gall y cynnwys hwn fod yn anniogel
+# Variables:
+#   $content - Description of the content being warned about, such as "clipboard" or "aFile.txt"
+contentanalysis-warndialogtext = Mae eich sefydliad yn defnyddio meddalwedd atal colli data sydd wedi nodi bod y cynnwys hwn yn anniogel: { $content }. Ei ddefnyddio beth bynnag?
+contentanalysis-warndialog-response-allow = Defnyddio'r cynnwys
+contentanalysis-warndialog-response-deny = Diddymu
+contentanalysis-notification-title = Dadansoddi Cynnwys
+# Variables:
+#   $content - Description of the content being reported, such as "clipboard" or "aFile.txt"
+#   $response - The response received from the content analysis agent, such as "REPORT_ONLY"
+contentanalysis-genericresponse-message = Ymatebodd Dadansoddi Cynnwys gyda { $response } am adnodd: { $content }
+# Variables:
+#   $content - Description of the content being blocked, such as "clipboard" or "aFile.txt"
+contentanalysis-block-message = Mae eich sefydliad yn defnyddio meddalwedd atal colli data sydd wedi rhwystro'r cynnwys hwn: { $content }.
+# Variables:
+#   $content - Description of the content being blocked, such as "clipboard" or "aFile.txt"
+contentanalysis-error-message = Digwyddodd gwall wrth gyfathrebu â'r feddalwedd atal colli data. Gwrthodwyd trosglwyddo adnodd: { $content }.
diff --git a/l10n-cy/toolkit/toolkit/downloads/downloadUI.ftl b/l10n-cy/toolkit/toolkit/downloads/downloadUI.ftl
new file mode 100644
index 0000000000..e70c09fe3a
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/downloads/downloadUI.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/.
+
+download-ui-confirm-title = Diddymu Pob Llwyth?
+
+## Variables:
+##   $downloadsCount (Number): The current downloads count.
+
+download-ui-confirm-quit-cancel-downloads =
+    { $downloadsCount ->
+        [1] Os fyddwch yn gadael, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am adael?
+       *[other] Os fyddwch yn gadael, bydd { $downloadsCount } llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael?
+    }
+download-ui-confirm-quit-cancel-downloads-mac =
+    { $downloadsCount ->
+        [1] Os fyddwch yn gadael, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am adael?
+       *[other] Os fyddwch yn gadael, bydd { $downloadsCount } llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael?
+    }
+download-ui-dont-quit-button =
+    { PLATFORM() ->
+        [mac] Peidio Gorffen
+       *[other] Peidio Gadael
+    }
+
+download-ui-confirm-offline-cancel-downloads =
+    { $downloadsCount ->
+        [1] Os fyddwch yn mynd all-lein, bydd 1 llwyth yn cael ei ddiddymu. Ydych chi'n siŵr eich bod am fynd all-lein?
+       *[other] Os fyddwch yn mynd all-lein, bydd { $downloadsCount } llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am fynd all-lein?
+    }
+download-ui-dont-go-offline-button = Aros Ar-lein
+
+download-ui-confirm-leave-private-browsing-windows-cancel-downloads =
+    { $downloadsCount ->
+        [1] 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?
+       *[other] Os ydych yn cau pob ffenestr Pori Preifat nawr, bydd { $downloadsCount } llwyth yn cael eu diddymu. Ydych chi'n siŵr eich bod am adael y modd Pori Preifat?
+    }
+download-ui-dont-leave-private-browsing-button = Aros yn y Modd Pori Preifat
+
+download-ui-cancel-downloads-ok =
+    { $downloadsCount ->
+        [1] Diddymu 1 Llwyth
+       *[other] Diddymu { $downloadsCount } Llwyth
+    }
+
+##
+
+download-ui-file-executable-security-warning-title = Agor Ffeil Gweithredadwy?
+# Variables:
+#   $executable (String): The executable file to be opened.
+download-ui-file-executable-security-warning = Mae "{ $executable }" 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 "{ $executable }"?
diff --git a/l10n-cy/toolkit/toolkit/downloads/downloadUtils.ftl b/l10n-cy/toolkit/toolkit/downloads/downloadUtils.ftl
new file mode 100644
index 0000000000..9c1e651d18
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/downloads/downloadUtils.ftl
@@ -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/.
+
+## Variables:
+## $timeValue (number) - Number of units of time
+
+# Short form for seconds
+download-utils-short-seconds =
+    { $timeValue ->
+        [zero] e
+        [one] e
+        [two] e
+        [few] e
+        [many] e
+       *[other] e
+    }
+# Short form for minutes
+download-utils-short-minutes =
+    { $timeValue ->
+        [zero] m
+        [one] m
+        [two] m
+        [few] m
+        [many] m
+       *[other] m
+    }
+# Short form for hours
+download-utils-short-hours =
+    { $timeValue ->
+        [zero] a
+        [one] a
+        [two] a
+        [few] a
+        [many] a
+       *[other] a
+    }
+# Short form for days
+download-utils-short-days =
+    { $timeValue ->
+        [zero] d
+        [one] d
+        [two] d
+        [few] d
+        [many] d
+       *[other] d
+    }
+
+##
+
+# — is the "em dash" (long dash)
+# example: 4 minutes left — 1.1 of 11.1 GB (2.2 MB/sec)
+# Variables:
+#   $timeLeft (String): time left.
+#   $transfer (String): transfer progress.
+#   $rate (String): rate number.
+#   $unit (String): rate unit.
+download-utils-status = { $timeLeft } — { $transfer } ({ $rate } { $unit }/sec)
+# If download speed is a JavaScript Infinity value, this phrase is used
+# — is the "em dash" (long dash)
+# example: 4 minutes left — 1.1 of 11.1 GB (Really fast)
+# Variables:
+#   $timeLeft (String): time left.
+#   $transfer (String): transfer progress.
+download-utils-status-infinite-rate = { $timeLeft } — { $transfer } (Cyflym iawn)
+# — is the "em dash" (long dash)
+# example: 4 minutes left — 1.1 of 11.1 GB
+# Variables:
+#   $timeLeft (String): time left.
+#   $transfer (String): transfer progress.
+download-utils-status-no-rate = { $timeLeft } — { $transfer }
+
+download-utils-bytes = beit
+download-utils-kilobyte = KB
+download-utils-megabyte = MB
+download-utils-gigabyte = GB
+
+# example: 1.1 of 333 MB
+# Variables:
+#   $progress (String): progress number.
+#   $total (String): total number.
+#   $totalUnits (String): total unit.
+download-utils-transfer-same-units = { $progress } o { $total } { $totalUnits }
+# example: 11.1 MB of 3.3 GB
+# Variables:
+#   $progress (String): progress number.
+#   $progressUnits (String): progress unit.
+#   $total (String): total number.
+#   $totalUnits (String): total unit.
+download-utils-transfer-diff-units = { $progress } { $progressUnits } o { $total } { $totalUnits }
+# example: 111 KB
+# Variables:
+#   $progress (String): progress number.
+#   $progressUnits (String): unit.
+download-utils-transfer-no-total = { $progress } { $progressUnits }
+
+# examples: 1m; 11h
+# Variables:
+#   $time (String): time number.
+#   $unit (String): time unit.
+download-utils-time-pair = { $time } { $unit }
+# examples: 1m left; 11h left
+# Variables:
+#   $time (String): time left, including a unit
+download-utils-time-left-single = { $time } ar ôl
+# examples: 11h 2m left; 1d 22h left
+# Variables:
+#   $time1 (String): time left, including a unit
+#   $time2 (String): smaller measure of time left, including a unit
+download-utils-time-left-double = { $time1 } { $time2 } ar ôl
+download-utils-time-few-seconds = Ychydig eiliadau ar ôl
+download-utils-time-unknown = Amser anhysbys ar ôl
+
+# Variables:
+#   $scheme (String): URI scheme like data: jar: about:
+download-utils-done-scheme = Adnodd { $scheme }
+# Special case of done-scheme for file:
+# This is used as an eTLD replacement for local files, so make it lower case
+download-utils-done-file-scheme = ffeil leol
+
+# Displayed time for files finished yesterday
+download-utils-yesterday = Ddoe
diff --git a/l10n-cy/toolkit/toolkit/featuregates/features.ftl b/l10n-cy/toolkit/toolkit/featuregates/features.ftl
new file mode 100644
index 0000000000..b77c04ce66
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/featuregates/features.ftl
@@ -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/.
+
+# 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-description3 = Mae <a data-l10n-name="wikipedia-webgpu">WebGPU API</a> yn darparu cymorth lefel isel ar gyfer cyflawni rendrad cyfrifiant a graffeg gan ddefnyddio'r <a data-l10n-name="wikipedia-gpu">Prosesu Graffeg Uned (GPU)</a> o ddyfais neu gyfrifiadur y defnyddiwr. Mae fersiwn cyntaf y <a data-l10n-name="spec">fanyleb</a> bron â chael ei gwblhau. Gweler <a data-l10n-name="bugzilla">bug 1616739</a> am ragor 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-jxl =
+    .label = Cyfryngau: JPEG XL
+experimental-features-media-jxl-description = Gyda'r nodwedd hon wedi'i galluogi, mae { -brand-short-name } yn cefnogi fformat JPEG XL (JXL). Mae hwn yn fformat ffeil delwedd amgen sy'n cefnogi trosglwyddo  heb golled o ffeiliau JPEG traddodiadol. Darllenwch <a data-l10n-name="bugzilla">bug 1539075</a> am ragor 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-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.
+
+# "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.
+
+# 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/formautofill/formAutofill.ftl b/l10n-cy/toolkit/toolkit/formautofill/formAutofill.ftl
new file mode 100644
index 0000000000..e197d04005
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/formautofill/formAutofill.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/.
+
+
+## OS Prompt Dialog
+
+# The macos 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.
+autofill-use-payment-method-os-prompt-macos = defnyddio manylion cerdyn credyd wedi'i storio
+autofill-use-payment-method-os-prompt-windows = Mae { -brand-short-name } yn ceisio defnyddio manylion dull talu sydd wedi'i storio. Cadarnhewch fynediad i'r cyfrif Windows hwn isod.
+autofill-use-payment-method-os-prompt-other = Mae { -brand-short-name } yn ceisio defnyddio manylion dull talu sydd wedi'i storio.
+# In macOS, this string is preceded by the operating system with "Firefox is trying to ",
+# and has a period added to its end. Make sure to test in your locale.
+autofill-edit-payment-method-os-prompt-macos = dangos manylion dull talu wedi'i storio
+autofill-edit-payment-method-os-prompt-windows = Mae { -brand-short-name } yn ceisio dangos manylion dull talu sydd wedi'i storio. Cadarnhewch fynediad i'r cyfrif Windows hwn isod.
+autofill-edit-payment-method-os-prompt-other = Mae { -brand-short-name } yn ceisio dangos manylion dull talu sydd wedi'i storio.
+# The links lead users to Form Autofill browser preferences.
+autofill-options-link = Dewisiadau Awtolanw Ffurflenni
+autofill-options-link-osx = Dewisiadau Awtolanw Ffurflenni
+
+## The credit card capture doorhanger
+
+# If Sync is enabled and credit card sync is available,
+# this checkbox is displayed on the doorhanger shown when saving credit card.
+credit-card-doorhanger-credit-cards-sync-checkbox = Cydweddu'r holl gardiau sydd wedi'u cadw ar draws fy nyfeisiau
+# Used on the doorhanger when users submit payment with credit card.
+credit-card-save-doorhanger-header = Cadw’r cerdyn hwn yn ddiogel?
+credit-card-save-doorhanger-description = Mae { -brand-short-name } yn amgryptio rhif eich cerdyn. Ni fydd eich cod diogelwch yn cael ei gadw.
+credit-card-capture-save-button =
+    .label = Cadw
+    .accessKey = C
+credit-card-capture-cancel-button =
+    .label = Nid nawr
+    .accessKey = N
+credit-card-capture-never-save-button =
+    .label = Peidio byth a chadw cardiau
+    .accessKey = P
+
+# Used on the doorhanger when an credit card change is detected.
+
+credit-card-update-doorhanger-header = Diweddaru'r cerdyn?
+credit-card-update-doorhanger-description = Cerdyn i'w ddiweddaru:
+credit-card-capture-save-new-button =
+    .label = Cadw fel cerdyn newydd
+    .accessKey = C
+credit-card-capture-update-button =
+    .label = Diweddaru'r cerdyn cyfredol
+    .accessKey = D
diff --git a/l10n-cy/toolkit/toolkit/global/alert.ftl b/l10n-cy/toolkit/toolkit/global/alert.ftl
new file mode 100644
index 0000000000..017692ecb6
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/alert.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/.
+
+alert-close =
+    .tooltiptext = Cau'r hysbysiad
+alert-settings-title =
+    .tooltiptext = Gosodiadau
+
+## Reminder Notifications
+
+notification-default-dismiss = Cau
diff --git a/l10n-cy/toolkit/toolkit/global/appPicker.ftl b/l10n-cy/toolkit/toolkit/global/appPicker.ftl
new file mode 100644
index 0000000000..934d246e63
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/appPicker.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/.
+
+app-picker-browse-button =
+    .buttonlabelextra2 = Pori…
+app-picker-send-msg =
+    .value = Anfon yr eitem at:
+app-picker-no-app-found =
+    .value = Heb ganfod rhaglen ar gyfer y math yma o ffeil.
diff --git a/l10n-cy/toolkit/toolkit/global/browser-utils.ftl b/l10n-cy/toolkit/toolkit/global/browser-utils.ftl
new file mode 100644
index 0000000000..285aa17ebd
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/browser-utils.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/.
+
+# Used for data: URLs where we don't have any useful origin information
+browser-utils-url-data = (data)
+
+# Used for extension URLs
+# Variables:
+#   $extension (string) - Name of the extension that generated the URL
+browser-utils-url-extension = Estyniad ( { $extension } )
diff --git a/l10n-cy/toolkit/toolkit/global/commonDialog.ftl b/l10n-cy/toolkit/toolkit/global/commonDialog.ftl
new file mode 100644
index 0000000000..c9fc030fa0
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/commonDialog.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/.
+
+common-dialog-title-null = Mae'r dudalen hon yn dweud
+common-dialog-title-system = { -brand-short-name }
+# Title displayed when the origin of a web dialog is unknown.
+common-dialog-title-unknown = Anhysbys
+# An indicator showing that Firefox is waiting for an operation to finish
+common-dialog-spinner =
+    .alt = Prysur
+common-dialog-username =
+    .value = Enw Defnyddiwr
+common-dialog-password =
+    .value = Cyfrinair
+common-dialog-copy-cmd =
+    .label = Copïo
+    .accesskey = C
+common-dialog-select-all-cmd =
+    .label = Dewis Popeth
+    .accesskey = P
diff --git a/l10n-cy/toolkit/toolkit/global/contextual-identity.ftl b/l10n-cy/toolkit/toolkit/global/contextual-identity.ftl
new file mode 100644
index 0000000000..9d9e1acbd2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/contextual-identity.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/.
+
+
+## Names of the default containers in Firefox.
+## See https://support.mozilla.org/kb/how-use-firefox-containers
+
+user-context-personal =
+    .label = Personol
+    .accesskey = P
+user-context-work =
+    .label = Gwaith
+    .accesskey = G
+user-context-banking =
+    .label = Bancio
+    .accesskey = B
+user-context-shopping =
+    .label = Siopa
+    .accesskey = S
+
+##
+
+user-context-none =
+    .label = Dim Cynhwysydd
+    .accesskey = D
+user-context-manage-containers =
+    .label = Rheoli Cynwysyddion
+    .accesskey = R
diff --git a/l10n-cy/toolkit/toolkit/global/cookieBannerHandling.ftl b/l10n-cy/toolkit/toolkit/global/cookieBannerHandling.ftl
new file mode 100644
index 0000000000..f1860761e3
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/cookieBannerHandling.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/.
+
+cookie-banner-handled-webconsole = Mae { -brand-shorter-name } wedi trin baner cwci ar ran y defnyddiwr.
diff --git a/l10n-cy/toolkit/toolkit/global/createProfileWizard.ftl b/l10n-cy/toolkit/toolkit/global/createProfileWizard.ftl
new file mode 100644
index 0000000000..01272d092c
--- /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-window2 =
+    .title = Creu Proffil Dewin
+    .style = min-width: 45em; min-height: 32em;
+
+## First wizard page
+
+create-profile-first-page-header2 =
+    { PLATFORM() ->
+        [macos] Cyflwyniad
+       *[other] Croeso i { create-profile-window2.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-header2 =
+    { PLATFORM() ->
+        [macos] Diweddglo
+       *[other] Cwblhau { create-profile-window2.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/cspErrors.ftl b/l10n-cy/toolkit/toolkit/global/cspErrors.ftl
new file mode 100644
index 0000000000..a35dfe828b
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/cspErrors.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/.
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+csp-error-missing-directive = Nid yw'r polisi'n cynnwys cyfarwyddeb '{ $directive }' angenrheidiol
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+#   $keyword (String): the name of a CSP keyword, usually 'unsafe-inline'.
+csp-error-illegal-keyword = Mae '{ $directive }' yn cynnwys cyfarwyddeb gwaharddedig allweddair { $keyword }
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+#   $scheme (String): a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp-error-illegal-protocol = Mae '{ $directive }' yn cynnwys cyfarwyddeb gwaharddedig { $scheme }: protocol ffynhonnell
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+#   $scheme (String): a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp-error-missing-host = { $scheme }: mae'r protocol angen gwestai mewn cyfarwyddeb '{ $directive }'
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+#   $source (String): the name of a CSP source, usually 'self'.
+csp-error-missing-source = Rhaid i '{ $directive }' gynnwys y ffynhonnell { $source }
+
+# Variables:
+#   $directive (String): the name of a CSP directive, such as "script-src".
+#   $scheme (String): a protocol name, such as "http", which appears as "http:", as it would in a URL.
+csp-error-illegal-host-wildcard = { $scheme }: rhaid i ffynonellau cerdyn gwyllt o fewn cyfarwyddeb '{ $directive }' gynnwys o leiaf un isbarth generig (e.e., *.example.com yn lle *.com)
diff --git a/l10n-cy/toolkit/toolkit/global/datepicker.ftl b/l10n-cy/toolkit/toolkit/global/datepicker.ftl
new file mode 100644
index 0000000000..de426ab708
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/datepicker.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/.
+
+
+### Datepicker - Dialog for default HTML's <input type="date">
+
+
+## These labels are used by screenreaders and other assistive technology
+## to indicate the purpose of a date picker calendar and a month-year selection
+## spinner dialogs for HTML's <input type="date">
+
+date-picker-label =
+    .aria-label = Dewiswch ddyddiad
+date-spinner-label =
+    .aria-label = Dewiswch fis a blwyddyn
+
+## Text of the clear button
+
+date-picker-clear-button = Clirio
+
+## These labels are used by screenreaders and other assistive technology
+## to indicate the purpose of buttons that leaf through months of a calendar
+
+date-picker-previous =
+    .aria-label = Mis blaenorol
+date-picker-next =
+    .aria-label = Mis nesaf
+
+## These labels are used by screenreaders and other assistive technology
+## to indicate the type of a value/unit that is being selected within a
+## Month/Year date spinner dialogs on a datepicker calendar dialog
+
+date-spinner-month =
+    .aria-label = Mis
+date-spinner-year =
+    .aria-label = Blwyddyn
+
+## These labels are used by screenreaders and other assistive technology
+## to indicate the purpose of buttons that leaf through either months
+## or years of a Month/Year date spinner on a datepicker calendar dialog
+
+date-spinner-month-previous =
+    .aria-label = Mis blaenorol
+date-spinner-month-next =
+    .aria-label = Mis nesaf
+date-spinner-year-previous =
+    .aria-label = Llynedd
+date-spinner-year-next =
+    .aria-label = Blwyddyn nesaf
diff --git a/l10n-cy/toolkit/toolkit/global/datetimebox.ftl b/l10n-cy/toolkit/toolkit/global/datetimebox.ftl
new file mode 100644
index 0000000000..1896c4f656
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/datetimebox.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/.
+
+## Placeholders for date and time inputs
+
+datetime-year-placeholder = bbbb
+datetime-month-placeholder = mm
+datetime-day-placeholder = dd
+datetime-time-placeholder = --
+
+## Field labels for input type=date
+
+datetime-year =
+    .aria-label = Blwyddyn
+datetime-month =
+    .aria-label = Mis
+datetime-day =
+    .aria-label = Diwrnod
+
+## Field labels for input type=time
+
+datetime-hour =
+    .aria-label = Awr
+datetime-minute =
+    .aria-label = Munud
+datetime-second =
+    .aria-label = Eiliad
+datetime-millisecond =
+    .aria-label = Milieiliad
+datetime-dayperiod =
+    .aria-label = AM/PM
+
+## Calendar button for input type=date
+
+
+# This label is used by screenreaders and other assistive technology
+# to indicate the purpose of a toggle button inside of the <input type="date">
+# field that opens/closes a date picker calendar dialog
+
+datetime-calendar =
+    .aria-label = Calendr
diff --git a/l10n-cy/toolkit/toolkit/global/extensionPermissions.ftl b/l10n-cy/toolkit/toolkit/global/extensionPermissions.ftl
new file mode 100644
index 0000000000..623f86438a
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/extensionPermissions.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/.
+
+
+## Extension permission description keys are derived from permission names.
+## Permissions for which the message has been changed and the key updated
+## must have a corresponding entry in the `PERMISSION_L10N_ID_OVERRIDES` map.
+
+webext-perms-description-bookmarks = Darllen a newid nodau tudalen
+webext-perms-description-browserSettings = Darllen a newid gosodiadau'r porwr
+webext-perms-description-browsingData = Clirio'r hanes pori diweddar, cwcis a data cysylltiedig
+webext-perms-description-clipboardRead = Estyn data o'r clipfwrdd
+webext-perms-description-clipboardWrite = Mewnbynnu data i'r clipfwrdd
+webext-perms-description-declarativeNetRequest = Rhwystro cynnwys ar unrhyw dudalen
+webext-perms-description-declarativeNetRequestFeedback = Darllen eich hanes pori
+webext-perms-description-devtools = Estyn offer datblygwyr i gael mynediad at eich data mewn tabiau agored
+webext-perms-description-downloads = Llwytho i lawr, darllen ffeiliau a newid hanes llwytho i lawr y porwr
+webext-perms-description-downloads-open = Agor ffeiliau a llwythwyd i lawr i'ch cyfrifiadur
+webext-perms-description-find = Darllen testun yr holl dabiau sydd ar agor
+webext-perms-description-geolocation = Mynediad i'ch lleoliad
+webext-perms-description-history = Mynediad at eich hanes pori
+webext-perms-description-management = Monitro'r defnydd o estyniadau a rheoli themâu
+webext-perms-description-nativeMessaging = Cyfnewid negeseuon gyda rhaglenni ar wahân i { -brand-short-name }
+webext-perms-description-notifications = Dangos hysbysiadau i chi
+webext-perms-description-pkcs11 = Darparu gwasanaethau dilysiad cryptograffig
+webext-perms-description-privacy = Darllen a newid gosodiadau preifatrwydd
+webext-perms-description-proxy = Rheoli gosodiadau dirprwy'r porwr
+webext-perms-description-sessions = Mynediad at y tabiau caewyd yn ddiweddar
+webext-perms-description-tabs = Mynediad at dabiau'r porwyr
+webext-perms-description-tabHide = Cuddio a dangos tabiau'r porwr
+webext-perms-description-topSites = Mynediad at eich hanes pori
+webext-perms-description-webNavigation = Cael mynediad at weithgaredd wrth lywio
diff --git a/l10n-cy/toolkit/toolkit/global/extensions.ftl b/l10n-cy/toolkit/toolkit/global/extensions.ftl
new file mode 100644
index 0000000000..febb321f41
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/extensions.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/.
+
+
+## Headers used in the webextension permissions dialog,
+## 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 <, >, &
+## Variables:
+##   $extension (String): replaced with the localized name of the extension.
+
+webext-perms-header = Ychwanegu { $extension }?
+webext-perms-header-with-perms = Ychwanegu { $extension }? Bydd gan yr estyniad hwn ganiatâd i:
+webext-perms-header-unsigned = Ychwanegu { $extension }? Nid yw'r estyniad hwn wedi'i wirio. Gall estyniadau maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Ychwanegwch ef dim ond os ydych chi'n ymddiried yn y ffynhonnell.
+webext-perms-header-unsigned-with-perms = Ychwanegu { $extension }? Nid yw'r estyniad hwn wedi'i wirio. Gall estyniadau maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Ychwanegwch ef dim ond os ydych chi'n ymddiried yn y ffynhonnell. Bydd gan yr estyniad hwn ganiatâd i:
+webext-perms-sideload-header = Mae { $extension } wedi ei ychwanegu
+webext-perms-optional-perms-header = Mae { $extension } yn gofyn am ganiatâd ychwanegol.
+
+##
+
+webext-perms-add =
+    .label = Ychwanegu
+    .accesskey = Y
+webext-perms-cancel =
+    .label = Diddymu
+    .accesskey = D
+
+webext-perms-sideload-text = 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).
+webext-perms-sideload-text-no-perms = 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).
+webext-perms-sideload-enable =
+    .label = Galluogi
+    .accesskey = G
+webext-perms-sideload-cancel =
+    .label = Diddymu
+    .accesskey = D
+
+# Variables:
+#   $extension (String): replaced with the localized name of the extension.
+webext-perms-update-text = Mae { $extension } wedi'i ddiweddaru. Rhaid i chi gymeradwyo caniatâd newydd cyn y bydd y fersiwn wedi'i ddiweddaru'n cael ei osod. Bydd dewis “Diddymu” yn cynnal eich fersiwn estyniad cyfredol. Bydd gan yr estyniad hwn ganiatâd i:
+webext-perms-update-accept =
+    .label = Diweddaru
+    .accesskey = D
+
+webext-perms-optional-perms-list-intro = Mae eisiau:
+webext-perms-optional-perms-allow =
+    .label = Caniatáu
+    .accesskey = C
+webext-perms-optional-perms-deny =
+    .label = Gwrthod
+    .accesskey = G
+
+webext-perms-host-description-all-urls = Cael mynediad at eich data ar gyfer pob gwefan
+
+# Variables:
+#   $domain (String): will be replaced by the DNS domain for which a webextension is requesting access (e.g., mozilla.org)
+webext-perms-host-description-wildcard = Cael mynediad at eich data ym mhob gwefan ym mharth { $domain }
+
+# Variables:
+#   $domainCount (Number): Integer indicating the number of additional
+#     hosts for which this webextension is requesting permission.
+webext-perms-host-description-too-many-wildcards =
+    { $domainCount ->
+        [zero] Peidio cael mynediad at eich data mewn parthau eraill
+        [one] Cael mynediad at eich data mewn { $domainCount } parth arall
+        [two] Cael mynediad at eich data mewn { $domainCount } barth arall
+        [few] Cael mynediad at eich data mewn { $domainCount } parth arall
+        [many] Cael mynediad at eich data mewn { $domainCount } parth arall
+       *[other] Cael mynediad at eich data mewn { $domainCount } parth arall
+    }
+# Variables:
+#   $domain (String): will be replaced by the DNS host name for which a webextension is requesting access (e.g., www.mozilla.org)
+webext-perms-host-description-one-site = Cael mynediad at eich data yn { $domain }
+
+# Variables:
+#   $domainCount (Number): Integer indicating the number of additional
+#     hosts for which this webextension is requesting permission.
+webext-perms-host-description-too-many-sites =
+    { $domainCount ->
+        [zero] Peidio cael mynediad at eich data mewn gwefannau eraill
+        [one] Cael mynediad at eich data mewn { $domainCount } gwefan arall
+        [two] Cael mynediad at eich data mewn { $domainCount } wefan arall
+        [few] Cael mynediad at eich data mewn { $domainCount } gwefan arall
+        [many] Cael mynediad at eich data mewn { $domainCount } gwefan arall
+       *[other] Cael mynediad at eich data mewn { $domainCount } gwefan arall
+    }
+
+## Headers used in the webextension permissions dialog for synthetic add-ons.
+## The part of the string describing what privileges the extension gives should be consistent
+## with the value of webext-site-perms-description-gated-perms-{sitePermission}.
+## Note, this string will be used as raw markup. Avoid characters like <, >, &
+## Variables:
+##   $hostname (String): the hostname of the site the add-on is being installed from.
+
+webext-site-perms-header-with-gated-perms-midi = Mae'r ychwanegyn hwn yn rhoi mynediad i { $hostname } i'ch dyfeisiau MIDI.
+webext-site-perms-header-with-gated-perms-midi-sysex = Mae'r ychwanegyn hwn yn rhoi mynediad i { $hostname } i'ch dyfeisiau MIDI (gyda chefnogaeth SysEx).
+
+##
+
+# This string is used as description in the webextension permissions dialog for synthetic add-ons.
+# Note, the empty line is used to create a line break between the two sections.
+# Note, this string will be used as raw markup. Avoid characters like <, >, &
+webext-site-perms-description-gated-perms-midi =
+    Mae'r rhain fel arfer yn ddyfeisiadau plygio i mewn fel syntheseisyddion sain, ond efallai eu bod hefyd wedi'u cynnwys yn eich cyfrifiadur.
+    
+    Nid yw gwefannau yn cael mynediad i ddyfeisiau MIDI fel arfer. Gall ddefnydd amhriodol achosi difrod neu beryglu diogelwch.
+
+## Headers used in the webextension permissions dialog.
+## Note: This string will be used as raw markup. Avoid characters like <, >, &
+## Variables:
+##   $extension (String): replaced with the localized name of the extension being installed.
+##   $hostname (String): will be replaced by the DNS host name for which a webextension enables permissions.
+
+webext-site-perms-header-with-perms = Ychwanegu { $extension }? Mae'r estyniad hwn yn rhoi'r galluoedd canlynol i { $hostname }:
+webext-site-perms-header-unsigned-with-perms = Ychwanegu { $extension }? Nid yw'r estyniad hwn wedi'i wirio. Gall estyniadau maleisus ddwyn eich manylion preifat neu gyfaddawdu eich cyfrifiadur. Ychwanegwch ef dim ond os ydych chi'n ymddiried yn y ffynhonnell. Mae'r estyniad hwn yn rhoi'r galluoedd canlynol i { $hostname }:
+
+## These should remain in sync with permissions.NAME.label in sitePermissions.properties
+
+webext-site-perms-midi = Mynediad at ddyfeisiau MIDI
+webext-site-perms-midi-sysex = Mynediad at ddyfeisiau MIDI sydd â Chefnogaeth SysEx
diff --git a/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl b/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl
new file mode 100644
index 0000000000..f20869838c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/handlerDialog.ftl
@@ -0,0 +1,70 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Permission Dialog
+## Variables:
+##  $host (string) - The hostname that is initiating the request
+##  $scheme (string) - The type of link that's being opened.
+##  $appName (string) - Name of the application that will be opened.
+##  $extension (string) - Name of extension that initiated the request
+
+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-extension = Caniatáu i'r estyniad { $extension } 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 }?
+permission-dialog-description-extension-app = Caniatáu i'r estyniad { $extension } agor y ddolen { $scheme } gyda { $appName }?
+permission-dialog-description-system-app = Agor dolen { $scheme } gyda { $appName } ?
+permission-dialog-description-system-noapp = Agor dolen { $scheme }?
+
+## 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 (string) - The hostname that is initiating the request
+##  $scheme (string) - The type of link that's being opened.
+
+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-remember-extension = Gadewch i'r estyniad hwn 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 (string) - 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/htmlForm.ftl b/l10n-cy/toolkit/toolkit/global/htmlForm.ftl
new file mode 100644
index 0000000000..1ad2e47e8c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/htmlForm.ftl
@@ -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/.
+
+# 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).
+# Variables:
+#   $fileCount (Number): The number of remaining files.
+input-file-and-more-files =
+    { $fileCount ->
+        [zero] a 0 arall
+        [one] a { $fileCount } arall
+        [two] a { $fileCount } arall
+        [few] a { $fileCount } arall
+        [many] a { $fileCount } arall
+       *[other] a { $fileCount } arall
+    }
diff --git a/l10n-cy/toolkit/toolkit/global/mozCard.ftl b/l10n-cy/toolkit/toolkit/global/mozCard.ftl
new file mode 100644
index 0000000000..6fbe8159b2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/mozCard.ftl
@@ -0,0 +1,3 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
diff --git a/l10n-cy/toolkit/toolkit/global/mozFiveStar.ftl b/l10n-cy/toolkit/toolkit/global/mozFiveStar.ftl
new file mode 100644
index 0000000000..e350dec840
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/mozFiveStar.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 rating out of 5 stars.
+# Variables:
+#   $rating (number) - A number between 0 and 5. The translation should show at most one digit after the comma.
+moz-five-star-rating =
+    .title = Graddiwyd { NUMBER($rating, maximumFractionDigits: 1) } allan o 5
diff --git a/l10n-cy/toolkit/toolkit/global/mozMessageBar.ftl b/l10n-cy/toolkit/toolkit/global/mozMessageBar.ftl
new file mode 100644
index 0000000000..af086338db
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/mozMessageBar.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/.
+
+moz-message-bar-icon-info =
+    .alt = Manylion
+moz-message-bar-icon-warning =
+    .alt = Rhybudd
+moz-message-bar-icon-success =
+    .alt = Llwyddiant
+moz-message-bar-icon-error =
+    .alt = Gwall
+moz-message-bar-close-button =
+    .aria-label = Cau
+    .title = Cau
diff --git a/l10n-cy/toolkit/toolkit/global/mozSupportLink.ftl b/l10n-cy/toolkit/toolkit/global/mozSupportLink.ftl
new file mode 100644
index 0000000000..8b1b22cd9e
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/mozSupportLink.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/.
+
+moz-support-link-text = Darllen rhagor
diff --git a/l10n-cy/toolkit/toolkit/global/notification.ftl b/l10n-cy/toolkit/toolkit/global/notification.ftl
new file mode 100644
index 0000000000..899ffcdd7d
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/notification.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/.
+
+notification-learnmore-default-label =
+    .value = Darllen rhagor
+# This label is read by screen readers when focusing the close button for an
+# "infobar" (message shown when for example a popup is blocked),
+# and shown when hovering over the button
+notification-close-button =
+    .aria-label = Cau
+    .title = Cau
+close-notification-message =
+    .tooltiptext = Cau'r neges hon
diff --git a/l10n-cy/toolkit/toolkit/global/popupnotification.ftl b/l10n-cy/toolkit/toolkit/global/popupnotification.ftl
new file mode 100644
index 0000000000..ea9fa4b506
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/popupnotification.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/.
+
+popup-notification-learn-more = Darllen rhagor
+popup-notification-more-actions-button =
+    .aria-label = Rhagor o weithredoedd
+popup-notification-default-button =
+    .label = Iawn!
+    .accesskey = I
diff --git a/l10n-cy/toolkit/toolkit/global/processTypes.ftl b/l10n-cy/toolkit/toolkit/global/processTypes.ftl
new file mode 100644
index 0000000000..0ec3eda058
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/processTypes.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/.
+
+
+##
+## Localization for remote types defined in RemoteType.h
+##
+
+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 a webpage from other web pages
+# to improve security
+process-type-webisolated = Cynnwys Gwe Ynysig
+
+# process used to isolate a ServiceWorker to improve
+# performance
+process-type-webserviceworker = Gweithiwr Gwasanaeth Ynysig
+
+# process preallocated; may change to other types
+process-type-prealloc = Rhagddyranwyd
+
+##
+## Localization for Gecko process types defined in GeckoProcessTypes.h
+##
+
+process-type-default = Prif
+process-type-tab = Tab
+
+# 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 used to decode media
+process-type-rdd = RDD
+
+# process used to run some IPC actor in their own sandbox
+process-type-utility = Actor IPC mewn blwch tywod
+
+##
+## Other
+##
+
+# fallback
+process-type-unknown = Anhysbys
diff --git a/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl b/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl
new file mode 100644
index 0000000000..f66d928d79
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/profileDowngrade.ftl
@@ -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/.
+
+profiledowngrade-window2 =
+    .title = Rydych chi wedi cychwyn fersiwn hŷn o { -brand-product-name }
+    .style = min-width: 490px;
+profiledowngrade-window-create =
+    .label = Creu Proffil Newydd
+profiledowngrade-sync = 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 } cyfredol. Er mwyn diogelu'ch manylion, 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-sync2 = 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 } cyfredol. Er mwyn diogelu'ch manylion, crëwch broffil newydd ar gyfer y gosodiad hwn o { -brand-short-name }. Gallwch fewngofnodi gyda chyfrif 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 manylion, 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..cf4a22ce0c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/profileSelection.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/.
+
+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
+
+profile-selection-conflict-message = Mae copi arall o { -brand-product-name } wedi gwneud newidiadau i broffiliau. Rhaid ailgychwyn { -brand-short-name } cyn gwneud mwy o newidiadau.
+
+## 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..da584881ed
--- /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 } i'w osodiadau rhagosodedig?
+refresh-profile-dialog-button =
+    .label = Adnewyddu { -brand-short-name }
+refresh-profile-dialog-description = Ail gychwynnwch o'r newydd i ddatrys problemau perfformiad. Bydd hyn yn dileu eich estyniadau a'ch cyfaddasiadau. Fyddwch chi ddim yn colli gwybodaeth hanfodol fel nodau tudalen a chyfrineiriau.
+refresh-profile = Rhoi bywyd newydd i { -brand-short-name }
+refresh-profile-button = Adnewyddu { -brand-short-name }…
+refresh-profile-learn-more = Darllen rhagor
+refresh-profile-progress =
+    .title = Adnewyddu { -brand-short-name }
+refresh-profile-progress-description = Bron â gorffen…
diff --git a/l10n-cy/toolkit/toolkit/global/resistFingerPrinting.ftl b/l10n-cy/toolkit/toolkit/global/resistFingerPrinting.ftl
new file mode 100644
index 0000000000..33e9a7053f
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/resistFingerPrinting.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/.
+
+# 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?
diff --git a/l10n-cy/toolkit/toolkit/global/run-from-dmg.ftl b/l10n-cy/toolkit/toolkit/global/run-from-dmg.ftl
new file mode 100644
index 0000000000..8b43946363
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/run-from-dmg.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/.
+
+
+## Strings for a dialog that may open on macOS before the app's main window
+## opens. The dialog prompts the user to allow the app to install itself in an
+## appropriate location before relaunching itself from that location if the
+## user accepts.
+
+prompt-to-install-title = Gorffen gosod { -brand-short-name }?
+prompt-to-install-message = Cwblhewch y gosodiad un cam hwn i helpu i gadw { -brand-short-name } yn gyfredol a pheidio colli data. Bydd { -brand-short-name } yn cael ei ychwanegu at eich ffolder Rhaglenni a'ch Doc.
+prompt-to-install-yes-button = Gosod
+prompt-to-install-no-button = Peidio â Gosod
+
+## Strings for a dialog that opens if the installation failed.
+
+install-failed-title = Methodd gosod { -brand-short-name }.
+install-failed-message = Methodd { -brand-short-name } â gosod ond bydd yn parhau i redeg.
+
+## Strings for a dialog that recommends to the user to start an existing
+## installation of the app in the Applications directory if one is detected,
+## rather than the app that was double-clicked in a .dmg.
+
+prompt-to-launch-existing-app-title = Agor y rhaglen { -brand-short-name } presennol?
+prompt-to-launch-existing-app-message = Mae { -brand-short-name } eisoes wedi'i osod. Defnyddiwch y rhaglen sydd wedi'i osod i gael y wybodaeth ddiweddaraf ac atal colli data.
+prompt-to-launch-existing-app-yes-button = Agor yr un cyfredol
+prompt-to-launch-existing-app-no-button = Dim diolch
diff --git a/l10n-cy/toolkit/toolkit/global/tabprompts.ftl b/l10n-cy/toolkit/toolkit/global/tabprompts.ftl
new file mode 100644
index 0000000000..046d3c5b69
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/tabprompts.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/.
+
+tabmodalprompt-username =
+    .value = Enw Defnyddiwr:
+tabmodalprompt-password =
+    .value = Cyfrinair:
+
+tabmodalprompt-ok-button =
+    .label = Iawn
+tabmodalprompt-cancel-button =
+    .label = Diddymu
diff --git a/l10n-cy/toolkit/toolkit/global/textActions.ftl b/l10n-cy/toolkit/toolkit/global/textActions.ftl
new file mode 100644
index 0000000000..cd949fd996
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/textActions.ftl
@@ -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/.
+
+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
+# This command copies the link, removing additional
+# query parameters used to track users across sites.
+text-action-strip-on-share =
+    .label = Copi Heb Tracio Gwefan
+    .accesskey = G
+text-action-paste =
+    .label = Gludo
+    .accesskey = G
+text-action-paste-no-formatting =
+    .label = Gludo heb Fformatio
+    .accesskey = F
+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
+text-action-spell-no-suggestions =
+    .label = (Dim Awgrymiadau Sillafu)
+text-action-spell-add-to-dictionary =
+    .label = Ychwanegu at y Geiriadur
+    .accesskey = G
+text-action-spell-undo-add-to-dictionary =
+    .label = Dadwneud Ychwanegu at y Geiriadur
+    .accesskey = D
+text-action-spell-check-toggle =
+    .label = Gwirio Sillafu
+    .accesskey = S
+text-action-spell-add-dictionaries =
+    .label = Ychwanegu Geiriaduron…
+    .accesskey = Y
+text-action-spell-dictionaries =
+    .label = Iaith
+    .accesskey = I
+text-action-search-text-box-clear =
+    .title = Clirio
diff --git a/l10n-cy/toolkit/toolkit/global/timepicker.ftl b/l10n-cy/toolkit/toolkit/global/timepicker.ftl
new file mode 100644
index 0000000000..6fbe8159b2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/timepicker.ftl
@@ -0,0 +1,3 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
diff --git a/l10n-cy/toolkit/toolkit/global/tree.ftl b/l10n-cy/toolkit/toolkit/global/tree.ftl
new file mode 100644
index 0000000000..18aefe0e15
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/tree.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/.
+
+tree-columnpicker-restore-order =
+    .label = Adfer Trefn Colofnau
diff --git a/l10n-cy/toolkit/toolkit/global/unknownContentType.ftl b/l10n-cy/toolkit/toolkit/global/unknownContentType.ftl
new file mode 100644
index 0000000000..47cb173c7c
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/unknownContentType.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/.
+
+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 }.
+        }
+
+unknowncontenttype-intro = Rydych wedi dewis agor:
+unknowncontenttype-which-is = sydd yn:
+unknowncontenttype-from = oddi wrth:
+unknowncontenttype-prompt = Hoffech chi gadw'r ffeil?
+unknowncontenttype-action-question = Beth ddylai { -brand-short-name } wneud gyda'r ffeil?
+unknowncontenttype-open-with =
+    .label = Agor gyda
+    .accesskey = o
+unknowncontenttype-other =
+    .label = Arall…
+unknowncontenttype-choose-handler =
+    .label =
+        { PLATFORM() ->
+            [macos] Dewis…
+           *[other] Pori…
+        }
+    .accesskey =
+        { PLATFORM() ->
+            [macos] D
+           *[other] P
+        }
+unknowncontenttype-save-file =
+    .label = Cadw Ffeil
+    .accesskey = C
+unknowncontenttype-remember-choice =
+    .label = Gwneud hyn yn awtomatig ar gyfer ffeiliau o'r math yma o hyn ymlaen.
+    .accesskey = a
diff --git a/l10n-cy/toolkit/toolkit/global/videocontrols.ftl b/l10n-cy/toolkit/toolkit/global/videocontrols.ftl
new file mode 100644
index 0000000000..097778f068
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/global/videocontrols.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/.
+
+# 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
+
+videocontrols-play-button =
+    .aria-label = Chwarae
+videocontrols-pause-button =
+    .aria-label = Oedi
+videocontrols-mute-button =
+    .aria-label = Tewi
+videocontrols-unmute-button =
+    .aria-label = Dad dewi
+videocontrols-enterfullscreen-button =
+    .aria-label = Sgrin Lawn
+videocontrols-exitfullscreen-button =
+    .aria-label = Gadael y Sgrin Lawn
+videocontrols-casting-button-label =
+    .aria-label = Darlledu i'r Sgrin
+videocontrols-closed-caption-off =
+    .offlabel = Diffodd
+
+# This string is used as part of the Picture-in-Picture video toggle button when
+# the mouse is hovering it.
+videocontrols-picture-in-picture-label = Llun mewn Llun
+
+# 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.
+videocontrols-picture-in-picture-toggle-label2 = Agor allan y fideo hwn
+
+videocontrols-picture-in-picture-explainer3 = Mae rhagor o sgriniau'n fwy o hwyl. Chwaraewch y fideo hwn tra byddwch chi'n gwneud pethau eraill.
+
+videocontrols-error-aborted = Mae llwytho'r fideo wedi dod i ben.
+videocontrols-error-network = Mae chwarae'r fideo wedi dod i ben oherwydd gwall rhwydwaith.
+videocontrols-error-decode = Nid oedd modd chwarae'r fideo gan fod y ffeil yn llwgr.
+videocontrols-error-src-not-supported = Nid yw'r fformat fideo na'r math MIME yn cael eu cynnal.
+videocontrols-error-no-source = Heb ganfod fideo gyda fformat sy'n cael ei gynnal na math MIME.
+videocontrols-error-generic = Ataliwyd chwarae'r fideo oherwydd gwall anhysbys.
+videocontrols-status-picture-in-picture = Mae'r fideo hwn yn chwarae yn y modd Llun mewn Llun.
+
+# This message shows the current position and total video duration
+#
+# Variables:
+#   $position (String): The current media position
+#   $duration (String): The total video duration
+#
+# For example, when at the 5 minute mark in a 6 hour long video,
+# $position would be "5:00" and $duration would be "6:00:00", result
+# string would be "5:00 / 6:00:00". Note that $duration is not always
+# available. For example, when at the 5 minute mark in an unknown
+# duration video, $position would be "5:00" and the string which is
+# surrounded by <span> would be deleted, result string would be "5:00".
+videocontrols-position-and-duration-labels = { $position }<span data-l10n-name="position-duration-format"> / { $duration }</span>
+
+# This is a plain text version of the videocontrols-position-and-duration-labels
+# string, used by screenreaders.
+#
+# Variables:
+#   $position (String): The current media position
+#   $duration (String): The total video duration
+videocontrols-scrubber-position-and-duration =
+    .aria-label = Safle
+    .aria-valuetext = { $position } / { $duration }
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..67792fa8b4
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/intl/languageNames.ftl
@@ -0,0 +1,215 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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 = Kannada
+language-name-ko = Corëeg
+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-sat = Santali
+language-name-sc = Sardinieg
+language-name-sco = Scots
+language-name-sd = Sindhi
+language-name-se = Sami Gogleddol
+language-name-sg = Sango
+language-name-si = Sinhala
+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-szl = Silesaidd
+language-name-ta = Tamileg
+language-name-te = Telugu
+language-name-tg = Tajik
+language-name-th = Thai
+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..625d71c7d5
--- /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-2018 = Yr Iseldiroedd Caribïaidd
+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-2020 = Cape Verde
+region-name-cw = Curaçao
+region-name-cx = Ynys Christmas
+region-name-cy = Cyprus
+region-name-cz-2019 = Czechia
+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-2019 = Gogledd 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-2019 = Eswatini
+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..02fd3c4300
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/main-window/autocomplete.ftl
@@ -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/.
+
+
+### Import Logins Autocomplete
+
+
+## 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 = Darllen 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..ccaeaa5576
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/main-window/findbar.ftl
@@ -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/.
+
+
+### 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 = Diacritigau 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 Cyfan
+    .accesskey = G
+    .tooltiptext = Chwilio'r geiriau llawn yn unig
+
+findbar-not-found = Heb ganfod ymadrodd
+
+findbar-wrapped-to-top = Wedi cyrraedd diwedd y dudalen, parhau o'r brig
+findbar-wrapped-to-bottom = Wedi cyrraedd diwedd y dudalen, parhau o'r gwaelod
+
+findbar-normal-find =
+    .placeholder = Canfod ar y dudalen
+findbar-fast-find =
+    .placeholder = Canfod cyflym
+findbar-fast-find-links =
+    .placeholder = Canfod cyflym (dolenni'n unig)
+
+findbar-case-sensitive-status =
+    .value = (Mawr/bach)
+findbar-match-diacritics-status =
+    .value = (Diacritig cyfatebol)
+findbar-entire-word-status =
+    .value = (Geiriau cyfan yn unig)
+
+# Variables:
+#   $current (Number): Index of the currently selected match
+#   $total (Number): Total count of matches
+findbar-found-matches =
+    .value =
+        { $total ->
+            [zero] Dim cydweddiadau
+            [one] { $current } o { $total } cydweddiad
+            [two] { $current } o { $total } gydweddiad
+            [few] { $current } o { $total } cydweddiad
+            [many] { $current } o { $total } chydweddiad
+           *[other] { $current } o { $total } cydweddiad
+        }
+
+# Variables:
+#   $limit (Number): Total count of matches allowed before counting stops
+findbar-found-matches-count-limit =
+    .value =
+        { $limit ->
+            [zero] Dim cydweddiadau
+            [one] Mwy nag { $limit } cydweddiad
+            [two] Mwy na { $limit } gydweddiad
+            [few] Mwy nag { $limit } chydweddiad
+            [many] Mwy nag { $limit } chydweddiad
+           *[other] Mwy nag { $limit } cydweddiad
+        }
diff --git a/l10n-cy/toolkit/toolkit/neterror/certError.ftl b/l10n-cy/toolkit/toolkit/neterror/certError.ftl
new file mode 100644
index 0000000000..3331ce408e
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/neterror/certError.ftl
@@ -0,0 +1,141 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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:
+#   $hostname (string) - Hostname of the website with cert error.
+#   $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 = Cod gwall: { $error }
+
+# 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 SSL error.
+#   $errorMessage (string) - Error message corresponding to the type of error we are experiencing.
+cert-error-ssl-connection-error = Digwyddodd gwall wrth gysylltu â { $hostname }. { $errorMessage }
+
+# 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.
+
+cert-error-old-tls-version = Mae'n bosibl na fydd y wefan hon yn cefnogi'r protocol TLS 1.2, sef y fersiwn lleiaf a gefnogir gan { -brand-short-name }.
+
+# 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.
+
+dns-not-found-trr-only-title2 = Risg diogelwch posibl wrth chwilio'r parth hwn
+dns-not-found-native-fallback-title2 = Risg diogelwch posibl wrth chwilio'r parth hwn
+
+fileNotFound-title = Heb ganfod ffeil
+fileAccessDenied-title = Mae mynediad at y 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'r cyfnod 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
+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 â Chysylltu: 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/toolkit/toolkit/neterror/netError.ftl b/l10n-cy/toolkit/toolkit/neterror/netError.ftl
new file mode 100644
index 0000000000..5a7ece3493
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/neterror/netError.ftl
@@ -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/.
+
+
+## Error page titles
+
+neterror-page-title = Anhawster llwytho tudalen
+certerror-page-title = Rhybudd: Risg Diogelwch Posibl o'ch Blaen
+certerror-sts-page-title = Peidiwch â Chysylltu: Mater Diogelwch Posib
+neterror-blocked-by-policy-page-title = Tudalen wedi'i Rhwystro
+neterror-captive-portal-page-title = Mewngofnodi i'r rhwydwaith
+neterror-dns-not-found-title = Heb Ganfod Gweinydd
+neterror-malformed-uri-page-title = URL annilys
+
+## Error page actions
+
+neterror-advanced-button = Uwch…
+neterror-copy-to-clipboard-button = Copïo testun i'r clipfwrdd
+neterror-learn-more-link = Darllen rhagor…
+neterror-open-portal-login-page-button = Agor Tudalen Mewngofnodi i'r Rhwydwaith
+neterror-override-exception-button = Derbyn y Perygl a Pharhau
+neterror-pref-reset-button = Adfer y gosodiadau rhagosodedig
+neterror-return-to-previous-page-button = Mynd Nôl
+neterror-return-to-previous-page-recommended-button = Ewch Nôl (Argymell)
+neterror-try-again-button = Ceisiwch eto
+neterror-add-exception-button = Parhau bob tro ar gyfer y wefan hon
+neterror-settings-button = Newid gosodiadau DNS
+neterror-view-certificate-link = Darllen Tystysgrif
+neterror-trr-continue-this-time = Parhau'r tro yma
+neterror-disable-native-feedback-warning = Parhau bob tro
+
+##
+
+neterror-pref-reset = Mae'n edrych fel mai eich gosodiadau diogelwch rhwydwaith sy'n achosi hyn. Hoffech chi adfer y gosodiadau rhagosodedig?
+neterror-error-reporting-automatic = Mae adroddiadau gwall fel hyn y cynorthwyo { -vendor-short-name } i adnabod a rhwystro gwefannau maleisus
+
+## Specific error messages
+
+neterror-generic-error = Nid yw { -brand-short-name } yn gallu llwytho'r dudalen am ryw reswm.
+neterror-load-error-try-again = Efallai bod y wefan yn brysur neu nad yw ar gael dros dro. Ceisiwch eto ymhen ychydig.
+neterror-load-error-connection = Os nad ydych yn gallu llwytho unrhyw dudalennau, gwiriwch gysylltiad rhwydwaith eich cyfrifiadur.
+neterror-load-error-firewall = Os yw eich cyfrifiadur neu rwydwaith wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan { -brand-short-name } hawl i fynediad i'r we.
+neterror-captive-portal = Rhaid i chi fewngofnodi i'r rhwydwaith hwn cyn i chi gael mynediad i'r Rhyngrwyd.
+# Variables:
+# $hostAndPath (String) - a suggested site (e.g. "www.example.com") that the user may have meant instead.
+neterror-dns-not-found-with-suggestion = Oeddech chi'n bwriadu mynd i <a data-l10n-name="website">{ $hostAndPath }</a>?
+neterror-dns-not-found-hint-header = <strong>Os ydych chi wedi rhoi'r cyfeiriad cywir, gallwch:</strong>
+neterror-dns-not-found-hint-try-again = Ceisiwch eto yn nes ymlaen
+neterror-dns-not-found-hint-check-network = Gwiriwch eich cysylltiad rhwydwaith
+neterror-dns-not-found-hint-firewall = Gwiriwch fod gan { -brand-short-name } ganiatâd i gael mynediad i'r we (efallai eich bod wedi'ch cysylltu ond tu ôl i fur cadarn)
+
+## TRR-only specific messages
+## Variables:
+##   $hostname (String) - Hostname of the website to which the user was trying to connect.
+##   $trrDomain (String) - Hostname of the DNS over HTTPS server that is currently in use.
+
+neterror-dns-not-found-trr-only-reason = Nid yw { -brand-short-name } yn gallu diogelu eich cais am gyfeiriad y wefan hon trwy ein datryswr DNS dibynadwy. Dyma pam:
+neterror-dns-not-found-trr-only-reason2 = Nid yw { -brand-short-name } yn gallu diogelu eich cais am gyfeiriad y wefan hon trwy ein datryswr DNS dibynadwy. Dyma pam:
+neterror-dns-not-found-trr-third-party-warning2 = Gallwch barhau â datryswr DNS nad yw'n ddiogel. Fodd bynnag, efallai y bydd trydydd parti yn gallu gweld pa wefannau rydych chi'n ymweld â nhw.
+neterror-dns-not-found-trr-only-could-not-connect = Nid oedd modd i { -brand-short-name } gysylltu â { $trrDomain }.
+neterror-dns-not-found-trr-only-timeout = Cymerodd y cysylltiad i { $trrDomain } fwy o amser na'r disgwyl.
+neterror-dns-not-found-trr-offline = Nid ydych wedi'ch cysylltu â'r rhyngrwyd.
+neterror-dns-not-found-trr-unknown-host2 = Nid yw { $trrDomain } wedi canfod y wefan hon.
+neterror-dns-not-found-trr-server-problem = Bu anhawster gyda { $trrDomain }.
+neterror-dns-not-found-bad-trr-url = URL annilys.
+neterror-dns-not-found-trr-unknown-problem = Anhawster annisgwyl.
+
+## Native fallback specific messages
+## Variables:
+##   $trrDomain (String) - Hostname of the DNS over HTTPS server that is currently in use.
+
+neterror-dns-not-found-native-fallback-reason = Nid yw { -brand-short-name } yn gallu diogelu eich cais am gyfeiriad y wefan hon trwy ein datryswr DNS dibynadwy. Dyma pam:
+neterror-dns-not-found-native-fallback-reason2 = Nid yw { -brand-short-name } yn gallu diogelu eich cais am gyfeiriad y wefan hon trwy ein darparwr DNS dibynadwy. Dyma pam:
+neterror-dns-not-found-native-fallback-heuristic = Mae DNS dros HTTPS wedi'i analluogi ar eich rhwydwaith.
+neterror-dns-not-found-native-fallback-not-confirmed2 = Nid oedd modd i { -brand-short-name } gysylltu â { $trrDomain } .
+
+##
+
+neterror-file-not-found-filename = Gwiriwch yr enw ffeil am brif lythrennu neu wallau teipio eraill.
+neterror-file-not-found-moved = Gwiriwch i weld os yw'r ffeil wedi symud, ailenwi neu ei dileu.
+neterror-access-denied = Gall ei fod wedi ei dynnu, symud neu fod caniatâd ffeiliau yn rhwystro mynediad.
+neterror-unknown-protocol = Efallai bydd angen i chi osod meddalwedd arall i agor y cyfeiriad yma.
+neterror-redirect-loop = Gall y broblem yma fod wedi ei hachosi drwy analluogi neu wrthod cwci.
+neterror-unknown-socket-type-psm-installed = Gwiriwch fod gan eich system Reolwr Diogelwch Personol wedi ei osod.
+neterror-unknown-socket-type-server-config = Gall hyn fod oherwydd ffurfweddiad ansafonol ar y gweinydd.
+neterror-not-cached-intro = Nid yw'r ddogfen gofynnwyd amdani ar gael yn storfa dros dro { -brand-short-name }.
+neterror-not-cached-sensitive = Fel cam i sicrhau diogelwch nid yw { -brand-short-name } yn gofyn eto am ddogfennau sensitif.
+neterror-not-cached-try-again = Cliciwch Ceisio Eto i ofyn eto am y ddogfen o'r wefan.
+neterror-net-offline = Clicio “Ceisio newid eto” i newid i'r modd ar-lein ac ail lwytho'r dudalen.
+neterror-proxy-resolve-failure-settings = Gwiriwch osodiadau'r dirprwy i wneud yn siŵr eu bod yn gywir.
+neterror-proxy-resolve-failure-connection = Gwiriwch fod gan eich cyfrifiadur cyswllt a'r we sy'n gweithio.
+neterror-proxy-resolve-failure-firewall = Os yw eich cyfrifiadur neu rwydwaith wedi ei ddiogelu gan fur cadarn neu ddirprwy, gwnewch yn siŵr fod gan { -brand-short-name } hawl i fynediad i'r we.
+neterror-proxy-connect-failure-settings = Gwiriwch osodiadau'r dirprwy i wneud yn siŵr eu bod yn gywir.
+neterror-proxy-connect-failure-contact-admin = Cysylltwch â'ch gweinyddwr system i wneud yn siŵr fod y gweinydd dirprwyol yn gweithio.
+neterror-content-encoding-error = Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.
+neterror-unsafe-content-type = Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.
+neterror-nss-failure-not-verified = Nid oes modd dangos y dudalen rydych yn ceisio ei darllen am nad oes modd dilysu'r data rydych wedi ei dderbyn.
+neterror-nss-failure-contact-website = Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+certerror-intro = Mae { -brand-short-name } wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <b>{ $hostname }</b>. Os ewch i'r gwefan yma, gall ymosodwyr geisio dwyn gwybodaeth fel eich cyfrineiriau, e-byst neu fanylion cardiau credyd.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+certerror-sts-intro = Mae { -brand-short-name } wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <b>{ $hostname }</b> gan fod y wefan angen cysylltiad diogel.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+certerror-expired-cert-intro = Mae { -brand-short-name } wedi canfod bygythiad diogelwch posib ac nid yw wedi mynd i <b>{ $hostname }</b>. Un ai mae'r wefan wedi ei gam ffurfweddu neu mae cloc eich cyfrifiadur wedi ei osod i'r amser anghywir.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+# $mitm (String) - The name of the software intercepting communications between you and the website (or “man in the middle”)
+certerror-mitm = Mae <b>{ $hostname }</b> mwy na thebyg yn wefan diogel, ond nid oedd modd sefydlu cysylltiad diogel. Achoswyd hyn gan <b>{ $mitm }</b>, sy'n un a'i feddalwedd ar eich cyfrifiadur neu rwydwaith.
+neterror-corrupted-content-intro = Nid oes modd dangos y dudalen rydych yn ceisio ei gweld yn sgil canfod gwall trosglwyddo data.
+neterror-corrupted-content-contact-website = Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.
+# Do not translate "SSL_ERROR_UNSUPPORTED_VERSION".
+neterror-sslv3-used = Gwybodaeth uwch: SSL_ERROR_UNSUPPORTED_VERSION
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+neterror-inadequate-security-intro = <b>{ $hostname }</b> 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.
+# Do not translate "NS_ERROR_NET_INADEQUATE_SECURITY".
+neterror-inadequate-security-code = Cod gwall: NS_ERROR_NET_INADEQUATE_SECURITY
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+# $now (Date) - The current datetime, to be formatted as a date
+neterror-clock-skew-error = Mae eich cyfrifiadur yn meddwl ei bod hi'n { DATETIME($now, dateStyle: "medium") }, sy'n rhwystro { -brand-short-name } rhag cysylltu'n ddiogel. I fynd i <b>{ $hostname }</b>, diweddarwch gloc eich cyfrifiadur yng ngosodiadau eich system i'r dyddiad, amser a chylch amser cyfredol ac yna adnewyddu <b>{ $hostname }</b>.
+neterror-network-protocol-error-intro = Nid oes modd dangos y dudalen rydych yn ceisio'i gweld oherwydd cafwyd gwall yn y protocol rhwydwaith.
+neterror-network-protocol-error-contact-website = Cysylltwch â pherchnogion y wefan i'w hysbysu o'r anhawster.
+certerror-expired-cert-second-para = Mae'n debyg fod tystysgrif y wefan wedi dod i ben, sy'n atal { -brand-short-name } 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.
+certerror-expired-cert-sts-second-para = Mae'n debyg fod tystysgrif y wefan wedi dod i ben, sy'n atal { -brand-short-name } rhag cysylltu'n ddiogell.
+certerror-what-can-you-do-about-it-title = Beth allwch chi wneud am hyn?
+certerror-unknown-issuer-what-can-you-do-about-it-website = Mae hyn yn fater i'r wefan a does dim fedrwch chi wneud am y peth.
+certerror-unknown-issuer-what-can-you-do-about-it-contact-admin = 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.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+# $now (Date) - The current datetime, to be formatted as a date
+certerror-expired-cert-what-can-you-do-about-it-clock = Mae cloc eich cyfrifiadur wedi ei osod i { DATETIME($now, dateStyle: "medium") }. Gwnewch yn siŵr fod y dyddiad, amser a chylch amser yn gywir yn eich gosodiadau system ac yna adnewyddu <b>{ $hostname }</b>.
+certerror-expired-cert-what-can-you-do-about-it-contact-website = 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.
+certerror-bad-cert-domain-what-can-you-do-about-it = Mae'n fater i'r wefan a does dim fedrwch chi wneud i ddatrys y mater. Gallwch hysbysu gweinyddwr y wefan am y broblem.
+certerror-mitm-what-can-you-do-about-it-antivirus = 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.
+certerror-mitm-what-can-you-do-about-it-corporate = Os ydych ar rwydwaith corfforaethol, cysylltwch a'ch adran TG.
+# Variables:
+# $mitm (String) - The name of the software intercepting communications between you and the website (or “man in the middle”)
+certerror-mitm-what-can-you-do-about-it-attack = Os nad ydych yn gyfarwydd â <b>{ $mitm }</b>, yna gall hyn fod yn ymosodiad ac ni ddylech barhau ar y wefan hon.
+# Variables:
+# $mitm (String) - The name of the software intercepting communications between you and the website (or “man in the middle”)
+certerror-mitm-what-can-you-do-about-it-attack-sts = Os nad ydych yn gyfarwydd â <b>{ $mitm }</b>, yna gall hyn fod yn ymosodiad ac nid oes dim y gallwch ei wneud i gael mynediad i'r wefan.
+# Variables:
+# $hostname (String) - Hostname of the website to which the user was trying to connect.
+certerror-what-should-i-do-bad-sts-cert-explanation = Mae gan <b>{ $hostname }</b> bolisi diogelwch o'r enw HTTP Strict Transport Security (HSTS), sy'n golygu mai dim ond yn ddiogel mae modd i { -brand-short-name } gysylltu. Nid oes modd gosod eithriad er mwyn ymweld â'r wefan.
diff --git a/l10n-cy/toolkit/toolkit/neterror/nsserrors.ftl b/l10n-cy/toolkit/toolkit/neterror/nsserrors.ftl
new file mode 100644
index 0000000000..5602328c2f
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/neterror/nsserrors.ftl
@@ -0,0 +1,349 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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.
+
+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.
+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
+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.
+
+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
+
+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.
diff --git a/l10n-cy/toolkit/toolkit/passwordmgr/passwordmgr.ftl b/l10n-cy/toolkit/toolkit/passwordmgr/passwordmgr.ftl
new file mode 100644
index 0000000000..0358839f55
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/passwordmgr/passwordmgr.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/.
+
+
+## Save and update password doorhanger
+
+# Variables
+#   $host (String) - Hostname for which the password is saved for.
+password-manager-save-password-message = Cadw cyfrinair { $host }?
+password-manager-save-password-button-deny =
+    .label = Nid nawr
+    .accesskey = N
+password-manager-save-password-button-allow =
+    .label = Cadw
+    .accesskey = C
+password-manager-save-password-button-never =
+    .label = Peidio Byth â Chadw
+    .accesskey = P
+# Variables
+#   $host (String) - Hostname for which the password is updated for.
+password-manager-update-password-message = Diweddaru cyfrinair { $host }?
+password-manager-update-password-button-delete =
+    .label = Tynnu'r cyfrinair sydd wedi'i gadw
+    .accesskey = T
+password-manager-update-login-add-username = Ychwanegu enw defnyddiwr i gyfrinair wedi’i gadw?
+password-manager-password-password-button-allow =
+    .label = Diweddaru
+    .accesskey = i
+password-manager-update-password-button-deny =
+    .label = Peidio â Diweddaru
+    .accesskey = P
+# This is displayed in place of the username when it is missing.
+password-manager-no-username-placeholder = Dim enw defnyddiwr
+password-manager-toggle-password =
+    .label = Dangos cyfrinair
+    .accesskey = d
+password-manager-confirm-password-change = Cadarnhau Newid Cyfrinair
+password-manager-select-username = Dewis pa fewngofnod i'w ddiweddaru:
diff --git a/l10n-cy/toolkit/toolkit/payments/payments.ftl b/l10n-cy/toolkit/toolkit/payments/payments.ftl
new file mode 100644
index 0000000000..fc93b145fb
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/payments/payments.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/.
+
+
+# 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
+#   $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/pdfviewer/viewer.ftl b/l10n-cy/toolkit/toolkit/pdfviewer/viewer.ftl
new file mode 100644
index 0000000000..9931629270
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/pdfviewer/viewer.ftl
@@ -0,0 +1,392 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+## Main toolbar buttons (tooltips and alt text for images)
+
+pdfjs-previous-button =
+    .title = Tudalen Flaenorol
+pdfjs-previous-button-label = Blaenorol
+pdfjs-next-button =
+    .title = Tudalen Nesaf
+pdfjs-next-button-label = Nesaf
+# .title: Tooltip for the pageNumber input.
+pdfjs-page-input =
+    .title = Tudalen
+# Variables:
+#   $pagesCount (Number) - the total number of pages in the document
+# This string follows an input field with the number of the page currently displayed.
+pdfjs-of-pages = o { $pagesCount }
+# Variables:
+#   $pageNumber (Number) - the currently visible page
+#   $pagesCount (Number) - the total number of pages in the document
+pdfjs-page-of-pages = ({ $pageNumber } o { $pagesCount })
+pdfjs-zoom-out-button =
+    .title = Chwyddo Allan
+pdfjs-zoom-out-button-label = Chwyddo Allan
+pdfjs-zoom-in-button =
+    .title = Chwyddo Mewn
+pdfjs-zoom-in-button-label = Chwyddo Mewn
+pdfjs-zoom-select =
+    .title = Chwyddo
+pdfjs-presentation-mode-button =
+    .title = Newid i'r Modd Cyflwyno
+pdfjs-presentation-mode-button-label = Modd Cyflwyno
+pdfjs-open-file-button =
+    .title = Agor Ffeil
+pdfjs-open-file-button-label = Agor
+pdfjs-print-button =
+    .title = Argraffu
+pdfjs-print-button-label = Argraffu
+pdfjs-save-button =
+    .title = Cadw
+pdfjs-save-button-label = Cadw
+# Used in Firefox for Android as a tooltip for the download button (“download” is a verb).
+pdfjs-download-button =
+    .title = Llwytho i Lawr
+# Used in Firefox for Android as a label for the download button (“download” is a verb).
+# Length of the translation matters since we are in a mobile context, with limited screen estate.
+pdfjs-download-button-label = Llwytho i Lawr
+pdfjs-bookmark-button =
+    .title = Tudalen Gyfredol (Gweld URL o'r Dudalen Gyfredol)
+pdfjs-bookmark-button-label = Tudalen Gyfredol
+# Used in Firefox for Android.
+pdfjs-open-in-app-button =
+    .title = Agor yn yr ap
+# Used in Firefox for Android.
+# Length of the translation matters since we are in a mobile context, with limited screen estate.
+pdfjs-open-in-app-button-label = Agor yn yr ap
+
+##  Secondary toolbar and context menu
+
+pdfjs-tools-button =
+    .title = Offer
+pdfjs-tools-button-label = Offer
+pdfjs-first-page-button =
+    .title = Mynd i'r Dudalen Gyntaf
+pdfjs-first-page-button-label = Mynd i'r Dudalen Gyntaf
+pdfjs-last-page-button =
+    .title = Mynd i'r Dudalen Olaf
+pdfjs-last-page-button-label = Mynd i'r Dudalen Olaf
+pdfjs-page-rotate-cw-button =
+    .title = Cylchdroi Clocwedd
+pdfjs-page-rotate-cw-button-label = Cylchdroi Clocwedd
+pdfjs-page-rotate-ccw-button =
+    .title = Cylchdroi Gwrthglocwedd
+pdfjs-page-rotate-ccw-button-label = Cylchdroi Gwrthglocwedd
+pdfjs-cursor-text-select-tool-button =
+    .title = Galluogi Dewis Offeryn Testun
+pdfjs-cursor-text-select-tool-button-label = Offeryn Dewis Testun
+pdfjs-cursor-hand-tool-button =
+    .title = Galluogi Offeryn Llaw
+pdfjs-cursor-hand-tool-button-label = Offeryn Llaw
+pdfjs-scroll-page-button =
+    .title = Defnyddio Sgrolio Tudalen
+pdfjs-scroll-page-button-label = Sgrolio Tudalen
+pdfjs-scroll-vertical-button =
+    .title = Defnyddio Sgrolio Fertigol
+pdfjs-scroll-vertical-button-label = Sgrolio Fertigol
+pdfjs-scroll-horizontal-button =
+    .title = Defnyddio Sgrolio Llorweddol
+pdfjs-scroll-horizontal-button-label = Sgrolio Llorweddol
+pdfjs-scroll-wrapped-button =
+    .title = Defnyddio Sgrolio Amlapio
+pdfjs-scroll-wrapped-button-label = Sgrolio Amlapio
+pdfjs-spread-none-button =
+    .title = Peidio uno trawsdaleniadau
+pdfjs-spread-none-button-label = Dim Trawsdaleniadau
+pdfjs-spread-odd-button =
+    .title = Uno trawsdaleniadau gan gychwyn gyda thudalennau odrif
+pdfjs-spread-odd-button-label = Trawsdaleniadau Odrif
+pdfjs-spread-even-button =
+    .title = Uno trawsdaleniadau gan gychwyn gyda thudalennau eilrif
+pdfjs-spread-even-button-label = Trawsdaleniadau Eilrif
+
+## Document properties dialog
+
+pdfjs-document-properties-button =
+    .title = Priodweddau Dogfen…
+pdfjs-document-properties-button-label = Priodweddau Dogfen…
+pdfjs-document-properties-file-name = Enw ffeil:
+pdfjs-document-properties-file-size = Maint ffeil:
+# Variables:
+#   $size_kb (Number) - the PDF file size in kilobytes
+#   $size_b (Number) - the PDF file size in bytes
+pdfjs-document-properties-kb = { $size_kb } KB ({ $size_b } beit)
+# Variables:
+#   $size_mb (Number) - the PDF file size in megabytes
+#   $size_b (Number) - the PDF file size in bytes
+pdfjs-document-properties-mb = { $size_mb } MB ({ $size_b } beit)
+pdfjs-document-properties-title = Teitl:
+pdfjs-document-properties-author = Awdur:
+pdfjs-document-properties-subject = Pwnc:
+pdfjs-document-properties-keywords = Allweddair:
+pdfjs-document-properties-creation-date = Dyddiad Creu:
+pdfjs-document-properties-modification-date = Dyddiad Addasu:
+# Variables:
+#   $date (Date) - the creation/modification date of the PDF file
+#   $time (Time) - the creation/modification time of the PDF file
+pdfjs-document-properties-date-string = { $date }, { $time }
+pdfjs-document-properties-creator = Crewr:
+pdfjs-document-properties-producer = Cynhyrchydd PDF:
+pdfjs-document-properties-version = Fersiwn PDF:
+pdfjs-document-properties-page-count = Cyfrif Tudalen:
+pdfjs-document-properties-page-size = Maint Tudalen:
+pdfjs-document-properties-page-size-unit-inches = o fewn
+pdfjs-document-properties-page-size-unit-millimeters = mm
+pdfjs-document-properties-page-size-orientation-portrait = portread
+pdfjs-document-properties-page-size-orientation-landscape = tirlun
+pdfjs-document-properties-page-size-name-a-three = A3
+pdfjs-document-properties-page-size-name-a-four = A4
+pdfjs-document-properties-page-size-name-letter = Llythyr
+pdfjs-document-properties-page-size-name-legal = Cyfreithiol
+
+## Variables:
+##   $width (Number) - the width of the (current) page
+##   $height (Number) - the height of the (current) page
+##   $unit (String) - the unit of measurement of the (current) page
+##   $name (String) - the name of the (current) page
+##   $orientation (String) - the orientation of the (current) page
+
+pdfjs-document-properties-page-size-dimension-string = { $width } × { $height } { $unit } ({ $orientation })
+pdfjs-document-properties-page-size-dimension-name-string = { $width } × { $height } { $unit } ({ $name }, { $orientation })
+
+##
+
+# The linearization status of the document; usually called "Fast Web View" in
+# English locales of Adobe software.
+pdfjs-document-properties-linearized = Golwg Gwe Cyflym:
+pdfjs-document-properties-linearized-yes = Iawn
+pdfjs-document-properties-linearized-no = Na
+pdfjs-document-properties-close-button = Cau
+
+## Print
+
+pdfjs-print-progress-message = Paratoi dogfen ar gyfer ei hargraffu…
+# Variables:
+#   $progress (Number) - percent value
+pdfjs-print-progress-percent = { $progress }%
+pdfjs-print-progress-close-button = Diddymu
+pdfjs-printing-not-supported = Rhybudd: Nid yw argraffu yn cael ei gynnal yn llawn gan y porwr.
+pdfjs-printing-not-ready = Rhybudd: Nid yw'r PDF wedi ei lwytho'n llawn ar gyfer argraffu.
+
+## Tooltips and alt text for side panel toolbar buttons
+
+pdfjs-toggle-sidebar-button =
+    .title = Toglo'r Bar Ochr
+pdfjs-toggle-sidebar-notification-button =
+    .title = Toglo'r Bar Ochr (mae'r ddogfen yn cynnwys amlinelliadau/atodiadau/haenau)
+pdfjs-toggle-sidebar-button-label = Toglo'r Bar Ochr
+pdfjs-document-outline-button =
+    .title = Dangos Amlinell Dogfen (clic dwbl i ymestyn/cau pob eitem)
+pdfjs-document-outline-button-label = Amlinelliad Dogfen
+pdfjs-attachments-button =
+    .title = Dangos Atodiadau
+pdfjs-attachments-button-label = Atodiadau
+pdfjs-layers-button =
+    .title = Dangos Haenau (cliciwch ddwywaith i ailosod yr holl haenau i'r cyflwr rhagosodedig)
+pdfjs-layers-button-label = Haenau
+pdfjs-thumbs-button =
+    .title = Dangos Lluniau Bach
+pdfjs-thumbs-button-label = Lluniau Bach
+pdfjs-current-outline-item-button =
+    .title = Canfod yr Eitem Amlinellol Gyfredol
+pdfjs-current-outline-item-button-label = Yr Eitem Amlinellol Gyfredol
+pdfjs-findbar-button =
+    .title = Canfod yn y Ddogfen
+pdfjs-findbar-button-label = Canfod
+pdfjs-additional-layers = Haenau Ychwanegol
+
+## Thumbnails panel item (tooltip and alt text for images)
+
+# Variables:
+#   $page (Number) - the page number
+pdfjs-thumb-page-title =
+    .title = Tudalen { $page }
+# Variables:
+#   $page (Number) - the page number
+pdfjs-thumb-page-canvas =
+    .aria-label = Llun Bach Tudalen { $page }
+
+## Find panel button title and messages
+
+pdfjs-find-input =
+    .title = Canfod
+    .placeholder = Canfod yn y ddogfen…
+pdfjs-find-previous-button =
+    .title = Canfod enghraifft flaenorol o'r ymadrodd
+pdfjs-find-previous-button-label = Blaenorol
+pdfjs-find-next-button =
+    .title = Canfod enghraifft nesaf yr ymadrodd
+pdfjs-find-next-button-label = Nesaf
+pdfjs-find-highlight-checkbox = Amlygu Popeth
+pdfjs-find-match-case-checkbox-label = Cydweddu Maint
+pdfjs-find-match-diacritics-checkbox-label = Diacritigau Cyfatebol
+pdfjs-find-entire-word-checkbox-label = Geiriau Cyfan
+pdfjs-find-reached-top = Wedi cyrraedd brig y dudalen, parhau o'r gwaelod
+pdfjs-find-reached-bottom = Wedi cyrraedd diwedd y dudalen, parhau o'r brig
+# Variables:
+#   $current (Number) - the index of the currently active find result
+#   $total (Number) - the total number of matches in the document
+pdfjs-find-match-count =
+    { $total ->
+        [zero] { $current } o { $total } cydweddiadau
+        [one] { $current } o { $total } cydweddiad
+        [two] { $current } o { $total } gydweddiad
+        [few] { $current } o { $total } cydweddiad
+        [many] { $current } o { $total } chydweddiad
+       *[other] { $current } o { $total } cydweddiad
+    }
+# Variables:
+#   $limit (Number) - the maximum number of matches
+pdfjs-find-match-count-limit =
+    { $limit ->
+        [zero] Mwy nag { $limit } cydweddiadau
+        [one] Mwy nag { $limit } cydweddiad
+        [two] Mwy nag { $limit } gydweddiad
+        [few] Mwy nag { $limit } cydweddiad
+        [many] Mwy nag { $limit } chydweddiad
+       *[other] Mwy nag { $limit } cydweddiad
+    }
+pdfjs-find-not-found = Heb ganfod ymadrodd
+
+## Predefined zoom values
+
+pdfjs-page-scale-width = Lled Tudalen
+pdfjs-page-scale-fit = Ffit Tudalen
+pdfjs-page-scale-auto = Chwyddo Awtomatig
+pdfjs-page-scale-actual = Maint Gwirioneddol
+# Variables:
+#   $scale (Number) - percent value for page scale
+pdfjs-page-scale-percent = { $scale }%
+
+## PDF page
+
+# Variables:
+#   $page (Number) - the page number
+pdfjs-page-landmark =
+    .aria-label = Tudalen { $page }
+
+## Loading indicator messages
+
+pdfjs-loading-error = Digwyddodd gwall wrth lwytho'r PDF.
+pdfjs-invalid-file-error = Ffeil PDF annilys neu llwgr.
+pdfjs-missing-file-error = Ffeil PDF coll.
+pdfjs-unexpected-response-error = Ymateb annisgwyl gan y gweinydd.
+pdfjs-rendering-error = Digwyddodd gwall wrth adeiladu'r dudalen.
+
+## Annotations
+
+# Variables:
+#   $date (Date) - the modification date of the annotation
+#   $time (Time) - the modification time of the annotation
+pdfjs-annotation-date-string = { $date }, { $time }
+# .alt: This is used as a tooltip.
+# Variables:
+#   $type (String) - 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"
+pdfjs-text-annotation-type =
+    .alt = [Anodiad { $type } ]
+
+## Password
+
+pdfjs-password-label = Rhowch gyfrinair i agor y PDF.
+pdfjs-password-invalid = Cyfrinair annilys. Ceisiwch eto.
+pdfjs-password-ok-button = Iawn
+pdfjs-password-cancel-button = Diddymu
+pdfjs-web-fonts-disabled = Ffontiau gwe wedi eu hanalluogi: methu defnyddio ffontiau PDF mewnblanedig.
+
+## Editing
+
+pdfjs-editor-free-text-button =
+    .title = Testun
+pdfjs-editor-free-text-button-label = Testun
+pdfjs-editor-ink-button =
+    .title = Lluniadu
+pdfjs-editor-ink-button-label = Lluniadu
+pdfjs-editor-stamp-button =
+    .title = Ychwanegu neu olygu delweddau
+pdfjs-editor-stamp-button-label = Ychwanegu neu olygu delweddau
+pdfjs-editor-remove-button =
+    .title = Tynnu
+
+## Remove button for the various kind of editor.
+
+pdfjs-editor-remove-ink-button =
+    .title = Dileu lluniad
+pdfjs-editor-remove-freetext-button =
+    .title = Dileu testun
+pdfjs-editor-remove-stamp-button =
+    .title = Dileu delwedd
+pdfjs-editor-remove-highlight-button =
+    .title = Tynnu amlygiad
+
+##
+
+# Editor Parameters
+pdfjs-editor-free-text-color-input = Lliw
+pdfjs-editor-free-text-size-input = Maint
+pdfjs-editor-ink-color-input = Lliw
+pdfjs-editor-ink-thickness-input = Trwch
+pdfjs-editor-ink-opacity-input = Didreiddedd
+pdfjs-editor-stamp-add-image-button =
+    .title = Ychwanegu delwedd
+pdfjs-editor-stamp-add-image-button-label = Ychwanegu delwedd
+pdfjs-free-text =
+    .aria-label = Golygydd Testun
+pdfjs-free-text-default-content = Cychwyn teipio…
+pdfjs-ink =
+    .aria-label = Golygydd Lluniadu
+pdfjs-ink-canvas =
+    .aria-label = Delwedd wedi'i chreu gan ddefnyddwyr
+
+## Alt-text dialog
+
+# Alternative text (alt text) helps when people can't see the image.
+pdfjs-editor-alt-text-button-label = Testun amgen (alt)
+pdfjs-editor-alt-text-edit-button-label = Golygu testun amgen
+pdfjs-editor-alt-text-dialog-label = Dewisiadau
+pdfjs-editor-alt-text-dialog-description = Mae testun amgen (testun alt) yn helpu pan na all pobl weld y ddelwedd neu pan nad yw'n llwytho.
+pdfjs-editor-alt-text-add-description-label = Ychwanegu disgrifiad
+pdfjs-editor-alt-text-add-description-description = Anelwch at 1-2 frawddeg sy'n disgrifio'r pwnc, y cefndir neu'r gweithredoedd.
+pdfjs-editor-alt-text-mark-decorative-label = Marcio fel addurniadol
+pdfjs-editor-alt-text-mark-decorative-description = Mae'n cael ei ddefnyddio ar gyfer delweddau addurniadol, fel borderi neu farciau dŵr.
+pdfjs-editor-alt-text-cancel-button = Diddymu
+pdfjs-editor-alt-text-save-button = Cadw
+pdfjs-editor-alt-text-decorative-tooltip = Marcio fel addurniadol
+# .placeholder: This is a placeholder for the alt text input area
+pdfjs-editor-alt-text-textarea =
+    .placeholder = Er enghraifft, “Mae dyn ifanc yn eistedd wrth fwrdd i fwyta pryd bwyd”
+
+## Editor resizers
+## This is used in an aria label to help to understand the role of the resizer.
+
+pdfjs-editor-resizer-label-top-left = Y gornel chwith uchaf — newid maint
+pdfjs-editor-resizer-label-top-middle = Canol uchaf - newid maint
+pdfjs-editor-resizer-label-top-right = Y gornel dde uchaf - newid maint
+pdfjs-editor-resizer-label-middle-right = De canol - newid maint
+pdfjs-editor-resizer-label-bottom-right = Y gornel dde isaf — newid maint
+pdfjs-editor-resizer-label-bottom-middle = Canol gwaelod — newid maint
+pdfjs-editor-resizer-label-bottom-left = Y gornel chwith isaf — newid maint
+pdfjs-editor-resizer-label-middle-left = Chwith canol — newid maint
+
+## Color picker
+
+# This means "Color used to highlight text"
+pdfjs-editor-highlight-colorpicker-label = Lliw amlygu
+pdfjs-editor-colorpicker-button =
+    .title = Newid lliw
+pdfjs-editor-colorpicker-dropdown =
+    .aria-label = Dewisiadau lliw
+pdfjs-editor-colorpicker-yellow =
+    .title = Melyn
+pdfjs-editor-colorpicker-green =
+    .title = Gwyrdd
+pdfjs-editor-colorpicker-blue =
+    .title = Glas
+pdfjs-editor-colorpicker-pink =
+    .title = Pinc
+pdfjs-editor-colorpicker-red =
+    .title = Coch
diff --git a/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.ftl b/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.ftl
new file mode 100644
index 0000000000..9295f2f886
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/pictureinpicture/pictureinpicture.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/.
+
+pictureinpicture-player-title = Llun mewn Llun
+
+## Variables:
+##   $shortcut (String) - Keyboard shortcut to execute the command.
+
+## Note that this uses .tooltip rather than the standard '.title'
+## or '.tooltiptext' -  but it has the same effect. Code in the
+## picture-in-picture window will read and copy this to an in-document
+## DOM node that then shows the tooltip.
+##
+## Variables:
+##   $shortcut (String) - Keyboard shortcut to execute the command.
+
+pictureinpicture-pause-btn =
+    .aria-label = Oedi
+    .tooltip = Oedi (Bar Bylchu)
+pictureinpicture-play-btn =
+    .aria-label = Chwarae
+    .tooltip = Chwarae (Bar Bylchu)
+
+pictureinpicture-mute-btn =
+    .aria-label = Tewi
+    .tooltip = Tewi ({ $shortcut })
+pictureinpicture-unmute-btn =
+    .aria-label = Dad-dewi
+    .tooltip = Dad-dewi ({ $shortcut })
+
+pictureinpicture-unpip-btn =
+    .aria-label = Anfon nôl i'r tab
+    .tooltip = Nôl i'r tab
+
+pictureinpicture-close-btn =
+    .aria-label = Cau
+    .tooltip = Cau ({ $shortcut })
+
+pictureinpicture-subtitles-btn =
+    .aria-label = Is-deitlau
+    .tooltip = Is-deitlau
+
+pictureinpicture-fullscreen-btn2 =
+    .aria-label = Sgrin Lawn
+    .tooltip = Sgrin Lawn (clic dwbl neu { $shortcut })
+
+pictureinpicture-exit-fullscreen-btn2 =
+    .aria-label = Gadael sgrin lawn
+    .tooltip = Gadael sgrin lawn (clic dwbl neu { $shortcut })
+
+##
+
+# Keyboard shortcut to toggle fullscreen mode when Picture-in-Picture is open.
+pictureinpicture-toggle-fullscreen-shortcut =
+    .key = F
+
+## Note that this uses .tooltip rather than the standard '.title'
+## or '.tooltiptext' -  but it has the same effect. Code in the
+## picture-in-picture window will read and copy this to an in-document
+## DOM node that then shows the tooltip.
+
+pictureinpicture-seekbackward-btn =
+    .aria-label = Mynd yn ôl
+    .tooltip = Mynd yn ôl (←)
+
+pictureinpicture-seekforward-btn =
+    .aria-label = Ymlaen
+    .tooltip = Ymlaen (→)
+
+##
+
+# This string is never displayed on the window. Is intended to be announced by
+# a screen reader whenever a user opens the subtitles settings panel
+# after selecting the subtitles button.
+pictureinpicture-subtitles-panel-accessible = Gosodiadau isdeitlau
+
+pictureinpicture-subtitles-label = Is-deitlau
+
+pictureinpicture-font-size-label = Maint ffont
+
+pictureinpicture-font-size-small = Bach
+
+pictureinpicture-font-size-medium = Canolig
+
+pictureinpicture-font-size-large = Mawr
diff --git a/l10n-cy/toolkit/toolkit/preferences/preferences.ftl b/l10n-cy/toolkit/toolkit/preferences/preferences.ftl
new file mode 100644
index 0000000000..88855d2025
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/preferences/preferences.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/.
+
+password-not-set =
+    .value = (heb ei osod)
+
+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.
+
+settings-pp-erased-ok = Rydych wedi dileu eich Prif Gyfrinair. Ni fydd cyfrineiriau wedi'u storio ac allweddi preifat tystysgrif sy'n cael ei reoli gan { -brand-short-name } yn cael eu diogelu.
+settings-pp-not-wanted = Rhybudd! Rydych wedi penderfynu peidio â defnyddio Prif Gyfrinair. Ni fydd cyfrineiriau wedi'u storio ac allweddi preifat tystysgrif sy'n cael eu rheoli gan { -brand-short-name } yn cael eu diogelu.
+
+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
+
+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
+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-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..8b1635c5a6
--- /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 = Tirlun
+    .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 = Yn 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..31f01fb299
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/printing/printPreview.ftl
@@ -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/.
+
+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 flaenorol
+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..3a44b29cff
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/printing/printUI.ftl
@@ -0,0 +1,152 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. 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-current = Cyfredol
+printui-page-range-odd = Odrif
+printui-page-range-even = Eilrif
+printui-page-range-custom = Cyfaddas
+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-two-sided-printing-off = Diffodd
+# Flip the sheet as if it were bound along its long edge.
+printui-two-sided-printing-long-edge = Fflipio ar ymyl hir
+# Flip the sheet as if it were bound along its short edge.
+printui-two-sided-printing-short-edge = Fflipio ar ymyl fer
+
+# Section title for miscellaneous print options
+printui-options = Dewisiadau
+printui-headers-footers-checkbox = Argraffu penynnau a throedynnau
+printui-backgrounds-checkbox = Argraffu cefndiroedd
+
+## The "Format" section, select a version of the website to print. Radio
+## options to select between the original page, selected text only, or a version
+## where the page is processed with "Reader View".
+
+# The section title.
+printui-source-label = Fformat
+# Option for printing the original page.
+printui-source-radio = Gwreiddiol
+# Option for printing just the content a user selected prior to printing.
+printui-selection-radio = Dewis
+# Option for "simplifying" the page by printing the Reader View version.
+printui-simplify-page-radio = Symleiddiwyd
+
+##
+
+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-mm = Cyfaddas (mm)
+printui-margins-custom-top = Brig
+printui-margins-custom-top-inches = Brig (modfeddi)
+printui-margins-custom-top-mm = Brig (mm)
+printui-margins-custom-bottom = Gwaelod
+printui-margins-custom-bottom-inches = Gwaelod (modfeddi)
+printui-margins-custom-bottom-mm = Gwaelod (mm)
+printui-margins-custom-left = Chwith
+printui-margins-custom-left-inches = Chwith (modfeddi)
+printui-margins-custom-left-mm = Chwith (mm)
+printui-margins-custom-right = De
+printui-margins-custom-right-inches = De (modfeddi)
+printui-margins-custom-right-mm = De (mm)
+
+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.
+printui-error-invalid-copies = Rhaid i gopïau fod yn rhif rhwng 1 a 10000.
+
+# 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/reportBrokenSite/reportBrokenSite.ftl b/l10n-cy/toolkit/toolkit/reportBrokenSite/reportBrokenSite.ftl
new file mode 100644
index 0000000000..6fbe8159b2
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/reportBrokenSite/reportBrokenSite.ftl
@@ -0,0 +1,3 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
diff --git a/l10n-cy/toolkit/toolkit/updates/backgroundupdate.ftl b/l10n-cy/toolkit/toolkit/updates/backgroundupdate.ftl
new file mode 100644
index 0000000000..aee9a60f17
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/updates/backgroundupdate.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/.
+
+backgroundupdate-task-description = Mae'r dasg Diweddariad Cefndir yn chwilio am ddiweddariadau i { -brand-short-name } pan nad yw { -brand-short-name } yn rhedeg. Mae'r dasg hon yn cael ei gosod yn awtomatig gan { -brand-short-name }, ac yn cael ei hailosod pan fydd { -brand-short-name } yn rhedeg. I analluogi'r dasg hon, diweddarwch osodiadau'r porwr neu'r gosodiad polisi menter { -brand-short-name } "BackgroundAppUpdate".
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..4a4b6dcb09
--- /dev/null
+++ b/l10n-cy/toolkit/toolkit/updates/history.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/.
+
+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 }
author	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 01:47:29 +0000
committer	Daniel Baumann <daniel.baumann@progress-linux.org>	2024-04-19 01:47:29 +0000
commit	0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d (patch)
tree	a31f07c9bcca9d56ce61e9a1ffd30ef350d513aa /l10n-cy/toolkit
parent	Initial commit. (diff)
download	firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.tar.xz firefox-esr-0ebf5bdf043a27fd3dfb7f92e0cb63d88954c44d.zip