Merging upstream version 126.0.

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

15 files changed, 833 insertions, 116 deletions

diff --git a/browser/components/preferences/preferences.js b/browser/components/preferences/preferences.js
index c30a51c67c..0cd498fd96 100644
--- a/browser/components/preferences/preferences.js
+++ b/browser/components/preferences/preferences.js
@@ -276,22 +276,6 @@ function init_all() {
   });
 }
 
-function telemetryBucketForCategory(category) {
-  category = category.toLowerCase();
-  switch (category) {
-    case "containers":
-    case "general":
-    case "home":
-    case "privacy":
-    case "search":
-    case "sync":
-    case "searchresults":
-      return category;
-    default:
-      return "unknown";
-  }
-}
-
 function onHashChange() {
   gotoPref(null, "hash");
 }
@@ -454,16 +438,6 @@ function search(aQuery, aAttribute) {
     }
     element.classList.remove("visually-hidden");
   }
-
-  let keysets = mainPrefPane.getElementsByTagName("keyset");
-  for (let element of keysets) {
-    let attributeValue = element.getAttribute(aAttribute);
-    if (attributeValue == aQuery) {
-      element.removeAttribute("disabled");
-    } else {
-      element.setAttribute("disabled", true);
-    }
-  }
 }
 
 async function spotlight(subcategory, category) {
diff --git a/browser/components/preferences/preferences.xhtml b/browser/components/preferences/preferences.xhtml
index eee227822a..64062f1f77 100644
--- a/browser/components/preferences/preferences.xhtml
+++ b/browser/components/preferences/preferences.xhtml
@@ -85,6 +85,8 @@
   <script type="module" src="chrome://global/content/elements/moz-toggle.mjs"/>
   <script type="module" src="chrome://global/content/elements/moz-message-bar.mjs" />
   <script type="module" src="chrome://global/content/elements/moz-label.mjs"/>
+  <script type="module" src="chrome://global/content/elements/moz-card.mjs"></script>
+  <script type="module" src="chrome://global/content/elements/moz-button.mjs"></script>
 </head>
 
 <html:body xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
@@ -224,7 +226,7 @@
           <hbox class="sticky-inner-container" pack="end" align="start">
             <hbox id="policies-container" class="info-box-container smaller-font-size" flex="1" hidden="true">
               <hbox class="info-icon-container">
-                <html:img class="info-icon"></html:img>
+                <html:img class="info-icon" data-l10n-attrs="alt" data-l10n-id="managed-notice-info-icon"></html:img>
               </hbox>
               <hbox align="center" flex="1">
                 <html:a href="about:policies" target="_blank" data-l10n-id="managed-notice"/>
diff --git a/browser/components/preferences/privacy.inc.xhtml b/browser/components/preferences/privacy.inc.xhtml
index 224a5f5cbb..5c45771bc2 100644
--- a/browser/components/preferences/privacy.inc.xhtml
+++ b/browser/components/preferences/privacy.inc.xhtml
@@ -1182,21 +1182,18 @@
     <label class="doh-status-label" id="dohResolver"/>
     <label class="doh-status-label" id="dohSteeringStatus" data-l10n-id="preferences-doh-steering-status" hidden="true"/>
   </vbox>
-  <hbox id="dohExceptionBox">
-    <label flex="1" data-l10n-id="preferences-doh-exceptions-description"/>
-    <button id="dohExceptionsButton"
-            is="highlightable-button"
-            class="accessory-button"
-            data-l10n-id="preferences-doh-manage-exceptions"
-            search-l10n-ids="
-              permissions-doh-entry-field,
-              permissions-doh-add-exception.label,
-              permissions-doh-remove.label,
-              permissions-doh-remove-all.label,
-              permissions-exceptions-doh-window.title,
-              permissions-exceptions-manage-doh-desc,
-            "/>
-  </hbox>
+  <button id="dohExceptionsButton"
+          is="highlightable-button"
+          class="accessory-button"
+          data-l10n-id="preferences-doh-manage-exceptions"
+          search-l10n-ids="
+            permissions-doh-entry-field,
+            permissions-doh-add-exception.label,
+            permissions-doh-remove.label,
+            permissions-doh-remove-all.label,
+            permissions-exceptions-doh-window.title,
+            permissions-exceptions-manage-doh-desc,
+          "/>
   <vbox>
     <label><html:h2 id="dohGroupMessage" data-l10n-id="preferences-doh-group-message2"/></label>
     <vbox id="dohCategories">
diff --git a/browser/components/preferences/privacy.js b/browser/components/preferences/privacy.js
index 3b07b9cabf..89fed04e21 100644
--- a/browser/components/preferences/privacy.js
+++ b/browser/components/preferences/privacy.js
@@ -60,6 +60,13 @@ ChromeUtils.defineLazyGetter(this, "AlertsServiceDND", function () {
   }
 });
 
+XPCOMUtils.defineLazyServiceGetter(
+  lazy,
+  "gParentalControlsService",
+  "@mozilla.org/parental-controls-service;1",
+  "nsIParentalControlsService"
+);
+
 XPCOMUtils.defineLazyPreferenceGetter(
   this,
   "OS_AUTH_ENABLED",
@@ -682,11 +689,14 @@ var gPrivacyPane = {
 
     function computeStatus() {
       let mode = Services.dns.currentTrrMode;
-      let confirmationState = Services.dns.currentTrrConfirmationState;
       if (
         mode == Ci.nsIDNSService.MODE_TRRFIRST ||
         mode == Ci.nsIDNSService.MODE_TRRONLY
       ) {
+        if (lazy.gParentalControlsService.parentalControlsEnabled) {
+          return "preferences-doh-status-not-active";
+        }
+        let confirmationState = Services.dns.currentTrrConfirmationState;
         switch (confirmationState) {
           case Ci.nsIDNSService.CONFIRM_TRYING_OK:
           case Ci.nsIDNSService.CONFIRM_OK:
@@ -702,7 +712,16 @@ var gPrivacyPane = {
 
     let errReason = "";
     let confirmationStatus = Services.dns.lastConfirmationStatus;
-    if (confirmationStatus != Cr.NS_OK) {
+    let mode = Services.dns.currentTrrMode;
+    if (
+      (mode == Ci.nsIDNSService.MODE_TRRFIRST ||
+        mode == Ci.nsIDNSService.MODE_TRRONLY) &&
+      lazy.gParentalControlsService.parentalControlsEnabled
+    ) {
+      errReason = Services.dns.getTRRSkipReasonName(
+        Ci.nsITRRSkipReason.TRR_PARENTAL_CONTROL
+      );
+    } else if (confirmationStatus != Cr.NS_OK) {
       errReason = ChromeUtils.getXPCOMErrorName(confirmationStatus);
     } else {
       errReason = Services.dns.getTRRSkipReasonName(
diff --git a/browser/components/preferences/sync.inc.xhtml b/browser/components/preferences/sync.inc.xhtml
index d3af690b93..492491a369 100644
--- a/browser/components/preferences/sync.inc.xhtml
+++ b/browser/components/preferences/sync.inc.xhtml
@@ -22,7 +22,7 @@
         <description id="noFxaDescription" class="description-deemphasized" flex="1" data-l10n-id="sync-signedout-description2"/>
       </vbox>
       <vbox>
-        <image class="fxaSyncIllustration"/>
+        <image class="fxaSyncIllustration" alt=""/>
       </vbox>
     </hbox>
     <hbox id="fxaNoLoginStatus" align="center" flex="1">
@@ -37,6 +37,7 @@
     </hbox>
     <label class="fxaMobilePromo" data-l10n-id="sync-mobile-promo">
       <html:img
+        role="none"
         src="chrome://browser/skin/logo-android.svg"
         data-l10n-name="android-icon"
         class="androidIcon"/>
@@ -44,6 +45,7 @@
         data-l10n-name="android-link"
         class="fxaMobilePromo-android text-link" target="_blank"/>
       <html:img
+        role="none"
         src="chrome://browser/skin/logo-ios.svg"
         data-l10n-name="ios-icon"
         class="iOSIcon"/>
@@ -66,7 +68,8 @@
               <image id="openChangeProfileImage"
                      class="fxaProfileImage actionable"
                      role="button"
-                     data-l10n-id="sync-profile-picture"/>
+                     data-l10n-attrs="alt"
+                     data-l10n-id="sync-profile-picture-with-alt"/>
               <vbox flex="1" pack="center">
                 <hbox flex="1" align="baseline">
                   <label id="fxaDisplayName" hidden="true">
@@ -88,11 +91,15 @@
             <!-- logged in to an unverified account -->
             <hbox id="fxaLoginUnverified">
               <vbox>
-                <image class="fxaProfileImage"/>
+                <image class="fxaProfileImage"
+                       data-l10n-attrs="alt"
+                       data-l10n-id="sync-profile-picture-account-problem"/>
               </vbox>
               <vbox flex="1" pack="center">
                 <hbox align="center">
-                  <image class="fxaLoginRejectedWarning"/>
+                  <image class="fxaLoginRejectedWarning"
+                         data-l10n-attrs="alt"
+                         data-l10n-id="fxa-login-rejected-warning"/>
                   <description flex="1"
                     class="l10nArgsEmailAddress"
                     data-l10n-id="sync-signedin-unverified"
@@ -112,11 +119,15 @@
             <!-- logged in locally but server rejected credentials -->
             <hbox id="fxaLoginRejected">
               <vbox>
-                <image class="fxaProfileImage"/>
+                <image class="fxaProfileImage"
+                       data-l10n-attrs="alt"
+                       data-l10n-id="sync-profile-picture-account-problem"/>
               </vbox>
               <vbox flex="1" pack="center">
                 <hbox align="center">
-                  <image class="fxaLoginRejectedWarning"/>
+                  <image class="fxaLoginRejectedWarning"
+                         data-l10n-attrs="alt"
+                         data-l10n-id="fxa-login-rejected-warning"/>
                   <description flex="1"
                     class="l10nArgsEmailAddress"
                     data-l10n-id="sync-signedin-login-failure"
@@ -187,35 +198,35 @@
                 <label data-l10n-id="sync-syncing-across-devices-heading"/>
                 <html:div class="sync-engines-list">
                   <html:div engine_preference="services.sync.engine.bookmarks">
-                    <image class="sync-engine-image sync-engine-bookmarks"/>
+                    <image class="sync-engine-image sync-engine-bookmarks" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-bookmarks"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.history">
-                    <image class="sync-engine-image sync-engine-history"/>
+                    <image class="sync-engine-image sync-engine-history" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-history"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.tabs">
-                    <image class="sync-engine-image sync-engine-tabs"/>
+                    <image class="sync-engine-image sync-engine-tabs" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-tabs"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.passwords">
-                    <image class="sync-engine-image sync-engine-passwords"/>
+                    <image class="sync-engine-image sync-engine-passwords" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-passwords"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.addresses">
-                    <image class="sync-engine-image sync-engine-addresses"/>
+                    <image class="sync-engine-image sync-engine-addresses" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-addresses"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.creditcards">
-                    <image class="sync-engine-image sync-engine-creditcards"/>
+                    <image class="sync-engine-image sync-engine-creditcards" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-payment-methods"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.addons">
-                    <image class="sync-engine-image sync-engine-addons"/>
+                    <image class="sync-engine-image sync-engine-addons" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-addons"/>
                   </html:div>
                   <html:div engine_preference="services.sync.engine.prefs">
-                    <image class="sync-engine-image sync-engine-prefs"/>
+                    <image class="sync-engine-image sync-engine-prefs" alt=""/>
                     <label data-l10n-id="sync-currently-syncing-settings"/>
                   </html:div>
                 </html:div>
diff --git a/browser/components/preferences/tests/browser.toml b/browser/components/preferences/tests/browser.toml
index 9e619ce4be..523110dbc9 100644
--- a/browser/components/preferences/tests/browser.toml
+++ b/browser/components/preferences/tests/browser.toml
@@ -10,6 +10,11 @@ support-files = [
   "addons/set_homepage.xpi",
   "addons/set_newtab.xpi",
 ]
+skip-if = [
+  "os == 'linux' && os_version == '18.04' && asan", # manifest runs too long
+  "os == 'linux' && os_version == '18.04' && tsan", # manifest runs too long
+  "win11_2009 && asan", # manifest runs too long
+]
 
 ["browser_about_settings.js"]
 
@@ -276,7 +281,6 @@ support-files = [
   "subdialog.xhtml",
   "subdialog2.xhtml",
 ]
-fail-if = ["a11y_checks"] # Bug 1854636 clicked label.dialogTitle, vbox#dialogTemplate.dialogOverlay may not be focusable
 
 ["browser_sync_chooseWhatToSync.js"]
 
diff --git a/browser/components/preferences/tests/browser_applications_selection.js b/browser/components/preferences/tests/browser_applications_selection.js
index 683ce76a89..23f0e00af8 100644
--- a/browser/components/preferences/tests/browser_applications_selection.js
+++ b/browser/components/preferences/tests/browser_applications_selection.js
@@ -335,10 +335,12 @@ add_task(async function sortingCheck() {
       "Number of items should not change."
     );
     for (let i = 0; i < siteItems.length - 1; ++i) {
-      let aType = siteItems[i].getAttribute("actionDescription").toLowerCase();
-      let bType = siteItems[i + 1]
-        .getAttribute("actionDescription")
-        .toLowerCase();
+      let aType = (
+        siteItems[i].getAttribute("actionDescription") || ""
+      ).toLowerCase();
+      let bType = (
+        siteItems[i + 1].getAttribute("actionDescription") || ""
+      ).toLowerCase();
       let result = 0;
       if (aType > bType) {
         result = 1;
@@ -375,10 +377,12 @@ add_task(async function sortingCheck() {
       "Number of items should not change."
     );
     for (let i = 0; i < siteItems.length - 1; ++i) {
-      let aType = siteItems[i].getAttribute("typeDescription").toLowerCase();
-      let bType = siteItems[i + 1]
-        .getAttribute("typeDescription")
-        .toLowerCase();
+      let aType = (
+        siteItems[i].getAttribute("typeDescription") || ""
+      ).toLowerCase();
+      let bType = (
+        siteItems[i + 1].getAttribute("typeDescription") || ""
+      ).toLowerCase();
       let result = 0;
       if (aType > bType) {
         result = 1;
diff --git a/browser/components/preferences/tests/browser_contentblocking.js b/browser/components/preferences/tests/browser_contentblocking.js
index 3d33f2ed7d..c178233a72 100644
--- a/browser/components/preferences/tests/browser_contentblocking.js
+++ b/browser/components/preferences/tests/browser_contentblocking.js
@@ -1021,7 +1021,7 @@ add_task(async function testDisableTPCheckBoxDisablesEmailTP() {
   // Verify the checkbox is unchecked after clicking.
   is(
     tpCheckbox.getAttribute("checked"),
-    "",
+    null,
     "Tracking protection checkbox is unchecked"
   );
 
diff --git a/browser/components/preferences/tests/browser_privacy_dnsoverhttps.js b/browser/components/preferences/tests/browser_privacy_dnsoverhttps.js
index 48469cfce4..ebe9c41127 100644
--- a/browser/components/preferences/tests/browser_privacy_dnsoverhttps.js
+++ b/browser/components/preferences/tests/browser_privacy_dnsoverhttps.js
@@ -16,6 +16,10 @@ ChromeUtils.defineESModuleGetters(this, {
   DoHTestUtils: "resource://testing-common/DoHTestUtils.sys.mjs",
 });
 
+const { MockRegistrar } = ChromeUtils.importESModule(
+  "resource://testing-common/MockRegistrar.sys.mjs"
+);
+
 const TRR_MODE_PREF = "network.trr.mode";
 const TRR_URI_PREF = "network.trr.uri";
 const TRR_CUSTOM_URI_PREF = "network.trr.custom_uri";
@@ -106,6 +110,164 @@ function waitForPrefObserver(name) {
   });
 }
 
+// Mock parental controls service in order to enable it
+let parentalControlsService = {
+  parentalControlsEnabled: true,
+  QueryInterface: ChromeUtils.generateQI(["nsIParentalControlsService"]),
+};
+let mockParentalControlsServiceCid = undefined;
+
+async function setMockParentalControlEnabled(aEnabled) {
+  if (mockParentalControlsServiceCid != undefined) {
+    MockRegistrar.unregister(mockParentalControlsServiceCid);
+    mockParentalControlsServiceCid = undefined;
+  }
+  if (aEnabled) {
+    mockParentalControlsServiceCid = MockRegistrar.register(
+      "@mozilla.org/parental-controls-service;1",
+      parentalControlsService
+    );
+  }
+  Services.dns.reloadParentalControlEnabled();
+}
+
+add_task(async function testParentalControls() {
+  async function withConfiguration(configuration, fn) {
+    info("testParentalControls");
+
+    await resetPrefs();
+    Services.prefs.setIntPref(TRR_MODE_PREF, configuration.trr_mode);
+    await setMockParentalControlEnabled(configuration.parentalControlsState);
+
+    await openPreferencesViaOpenPreferencesAPI("privacy", { leaveOpen: true });
+    let doc = gBrowser.selectedBrowser.contentDocument;
+    let statusElement = doc.getElementById("dohStatus");
+
+    await TestUtils.waitForCondition(() => {
+      return (
+        document.l10n.getAttributes(statusElement).args.status ==
+        configuration.wait_for_doh_status
+      );
+    });
+
+    await fn({
+      statusElement,
+    });
+
+    gBrowser.removeCurrentTab();
+    await setMockParentalControlEnabled(false);
+  }
+
+  info("Check parental controls disabled, TRR off");
+  await withConfiguration(
+    {
+      parentalControlsState: false,
+      trr_mode: 0,
+      wait_for_doh_status: "Off",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Off",
+        "expecting status off"
+      );
+    }
+  );
+
+  info("Check parental controls enabled, TRR off");
+  await withConfiguration(
+    {
+      parentalControlsState: true,
+      trr_mode: 0,
+      wait_for_doh_status: "Off",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Off",
+        "expecting status off"
+      );
+    }
+  );
+
+  // Enable the rollout.
+  await DoHTestUtils.loadRemoteSettingsConfig({
+    providers: "example",
+    rolloutEnabled: true,
+    steeringEnabled: false,
+    steeringProviders: "",
+    autoDefaultEnabled: false,
+    autoDefaultProviders: "",
+    id: "global",
+  });
+
+  info("Check parental controls disabled, TRR first");
+  await withConfiguration(
+    {
+      parentalControlsState: false,
+      trr_mode: 2,
+      wait_for_doh_status: "Active",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Active",
+        "expecting status active"
+      );
+    }
+  );
+
+  info("Check parental controls enabled, TRR first");
+  await withConfiguration(
+    {
+      parentalControlsState: true,
+      trr_mode: 2,
+      wait_for_doh_status: "Not active (TRR_PARENTAL_CONTROL)",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Not active (TRR_PARENTAL_CONTROL)",
+        "expecting status not active"
+      );
+    }
+  );
+
+  info("Check parental controls disabled, TRR only");
+  await withConfiguration(
+    {
+      parentalControlsState: false,
+      trr_mode: 3,
+      wait_for_doh_status: "Active",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Active",
+        "expecting status active"
+      );
+    }
+  );
+
+  info("Check parental controls enabled, TRR only");
+  await withConfiguration(
+    {
+      parentalControlsState: true,
+      trr_mode: 3,
+      wait_for_doh_status: "Not active (TRR_PARENTAL_CONTROL)",
+    },
+    async res => {
+      is(
+        document.l10n.getAttributes(res.statusElement).args.status,
+        "Not active (TRR_PARENTAL_CONTROL)",
+        "expecting status not active"
+      );
+    }
+  );
+
+  await resetPrefs();
+});
+
 async function testWithProperties(props, startTime) {
   info(
     Date.now() -
diff --git a/browser/components/preferences/tests/browser_subdialogs.js b/browser/components/preferences/tests/browser_subdialogs.js
index 8763ae9146..b604ac0a7f 100644
--- a/browser/components/preferences/tests/browser_subdialogs.js
+++ b/browser/components/preferences/tests/browser_subdialogs.js
@@ -173,7 +173,7 @@ async function close_subdialog_and_test_generic_end_state(
       );
       Assert.equal(
         frame.getAttribute("style"),
-        "",
+        null,
         "inline styles should be cleared"
       );
       Assert.equal(
@@ -407,17 +407,29 @@ add_task(async function background_click_should_close_dialog() {
   // Clicking on an inactive part of dialog itself should not close the dialog.
   // Click the dialog title bar here to make sure nothing happens.
   info("clicking the dialog title bar");
+  // We intentionally turn off this a11y check, because the following click
+  // is purposefully targeting a non-interactive element to confirm the opened
+  // dialog won't be dismissed. It is not meant to be interactive and is not
+  // expected to be accessible, therefore this rule check shall be ignored by
+  // a11y_checks suite.
+  AccessibilityUtils.setEnv({ mustHaveAccessibleRule: false });
   BrowserTestUtils.synthesizeMouseAtCenter(
     ".dialogTitle",
     {},
     tab.linkedBrowser
   );
+  AccessibilityUtils.resetEnv();
 
   // Close the dialog by clicking on the overlay background. Simulate a click
   // at point (2,2) instead of (0,0) so we are sure we're clicking on the
   // overlay background instead of some boundary condition that a real user
   // would never click.
   info("clicking the overlay background");
+  // We intentionally turn off this a11y check, because the following click
+  // is purposefully targeting a non-interactive element to dismiss the opened
+  // dialog with a mouse which can be done by assistive technology and keyboard
+  // by pressing `Esc` key, this rule check shall be ignored by a11y_checks.
+  AccessibilityUtils.setEnv({ mustHaveAccessibleRule: false });
   await close_subdialog_and_test_generic_end_state(
     tab.linkedBrowser,
     function () {
@@ -432,6 +444,7 @@ add_task(async function background_click_should_close_dialog() {
     0,
     { runClosingFnOutsideOfContentTask: true }
   );
+  AccessibilityUtils.resetEnv();
 });
 
 add_task(async function escape_should_close_dialog() {
diff --git a/browser/components/preferences/tests/siteData/browser.toml b/browser/components/preferences/tests/siteData/browser.toml
index 9f4f8306e1..b7e6ba1b6d 100644
--- a/browser/components/preferences/tests/siteData/browser.toml
+++ b/browser/components/preferences/tests/siteData/browser.toml
@@ -10,6 +10,8 @@ support-files = [
 
 ["browser_clearSiteData.js"]
 
+["browser_clearSiteData_v2.js"]
+
 ["browser_siteData.js"]
 
 ["browser_siteData2.js"]
diff --git a/browser/components/preferences/tests/siteData/browser_clearSiteData.js b/browser/components/preferences/tests/siteData/browser_clearSiteData.js
index 7ae1fda453..4924dccfea 100644
--- a/browser/components/preferences/tests/siteData/browser_clearSiteData.js
+++ b/browser/components/preferences/tests/siteData/browser_clearSiteData.js
@@ -7,10 +7,6 @@ const { PermissionTestUtils } = ChromeUtils.importESModule(
   "resource://testing-common/PermissionTestUtils.sys.mjs"
 );
 
-let useOldClearHistoryDialog = Services.prefs.getBoolPref(
-  "privacy.sanitize.useOldClearHistoryDialog"
-);
-
 async function testClearData(clearSiteData, clearCache) {
   PermissionTestUtils.add(
     TEST_QUOTA_USAGE_ORIGIN,
@@ -64,9 +60,7 @@ async function testClearData(clearSiteData, clearCache) {
   let doc = gBrowser.selectedBrowser.contentDocument;
   let clearSiteDataButton = doc.getElementById("clearSiteDataButton");
 
-  let url = useOldClearHistoryDialog
-    ? "chrome://browser/content/preferences/dialogs/clearSiteData.xhtml"
-    : "chrome://browser/content/sanitize_v2.xhtml";
+  let url = "chrome://browser/content/preferences/dialogs/clearSiteData.xhtml";
   let dialogOpened = promiseLoadSubDialog(url);
   clearSiteDataButton.doCommand();
   let dialogWin = await dialogOpened;
@@ -78,10 +72,8 @@ async function testClearData(clearSiteData, clearCache) {
   // since we've had cache intermittently changing under our feet.
   let [, convertedCacheUnit] = DownloadUtils.convertByteUnits(cacheUsage);
 
-  let cookiesCheckboxId = useOldClearHistoryDialog
-    ? "clearSiteData"
-    : "cookiesAndStorage";
-  let cacheCheckboxId = useOldClearHistoryDialog ? "clearCache" : "cache";
+  let cookiesCheckboxId = "clearSiteData";
+  let cacheCheckboxId = "clearCache";
   let clearSiteDataCheckbox =
     dialogWin.document.getElementById(cookiesCheckboxId);
   let clearCacheCheckbox = dialogWin.document.getElementById(cacheCheckboxId);
@@ -106,28 +98,13 @@ async function testClearData(clearSiteData, clearCache) {
   clearSiteDataCheckbox.checked = clearSiteData;
   clearCacheCheckbox.checked = clearCache;
 
-  if (!useOldClearHistoryDialog) {
-    // The new clear history dialog has a seperate checkbox for site settings
-    let siteSettingsCheckbox =
-      dialogWin.document.getElementById("siteSettings");
-    siteSettingsCheckbox.checked = clearSiteData;
-    // select clear everything to match the old dialog boxes behaviour for this test
-    let timespanSelection = dialogWin.document.getElementById(
-      "sanitizeDurationChoice"
-    );
-    timespanSelection.value = 0;
-  }
   // Some additional promises/assertions to wait for
   // when deleting site data.
   let acceptPromise;
   let updatePromise;
   let cookiesClearedPromise;
   if (clearSiteData) {
-    // the new clear history dialog does not have a extra prompt
-    // to clear site data after clicking clear
-    if (useOldClearHistoryDialog) {
-      acceptPromise = BrowserTestUtils.promiseAlertDialogOpen("accept");
-    }
+    acceptPromise = BrowserTestUtils.promiseAlertDialogOpen("accept");
     updatePromise = promiseSiteDataManagerSitesUpdated();
     cookiesClearedPromise = promiseCookiesCleared();
   }
@@ -137,7 +114,7 @@ async function testClearData(clearSiteData, clearCache) {
   let clearButton = dialogWin.document
     .querySelector("dialog")
     .getButton("accept");
-  if (!clearSiteData && !clearCache && useOldClearHistoryDialog) {
+  if (!clearSiteData && !clearCache) {
     // Simulate user input on one of the checkboxes to trigger the event listener for
     // disabling the clearButton.
     clearCacheCheckbox.doCommand();
@@ -158,7 +135,7 @@ async function testClearData(clearSiteData, clearCache) {
 
   // For site data we display an extra warning dialog, make sure
   // to accept it.
-  if (clearSiteData && useOldClearHistoryDialog) {
+  if (clearSiteData) {
     await acceptPromise;
   }
 
@@ -222,6 +199,12 @@ async function testClearData(clearSiteData, clearCache) {
   await SiteDataManager.removeAll();
 }
 
+add_setup(function () {
+  SpecialPowers.pushPrefEnv({
+    set: [["privacy.sanitize.useOldClearHistoryDialog", true]],
+  });
+});
+
 // Test opening the "Clear All Data" dialog and cancelling.
 add_task(async function () {
   await testClearData(false, false);
diff --git a/browser/components/preferences/tests/siteData/browser_clearSiteData_v2.js b/browser/components/preferences/tests/siteData/browser_clearSiteData_v2.js
new file mode 100644
index 0000000000..8cb8be25b3
--- /dev/null
+++ b/browser/components/preferences/tests/siteData/browser_clearSiteData_v2.js
@@ -0,0 +1,258 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { PermissionTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PermissionTestUtils.sys.mjs"
+);
+
+async function testClearData(clearSiteData, clearCache) {
+  PermissionTestUtils.add(
+    TEST_QUOTA_USAGE_ORIGIN,
+    "persistent-storage",
+    Services.perms.ALLOW_ACTION
+  );
+
+  // Open a test site which saves into appcache.
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, TEST_OFFLINE_URL);
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+
+  // Fill indexedDB with test data.
+  // Don't wait for the page to load, to register the content event handler as quickly as possible.
+  // If this test goes intermittent, we might have to tell the page to wait longer before
+  // firing the event.
+  BrowserTestUtils.openNewForegroundTab(gBrowser, TEST_QUOTA_USAGE_URL, false);
+  await BrowserTestUtils.waitForContentEvent(
+    gBrowser.selectedBrowser,
+    "test-indexedDB-done",
+    false,
+    null,
+    true
+  );
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+
+  // Register some service workers.
+  await loadServiceWorkerTestPage(TEST_SERVICE_WORKER_URL);
+  await promiseServiceWorkerRegisteredFor(TEST_SERVICE_WORKER_URL);
+
+  await openPreferencesViaOpenPreferencesAPI("privacy", { leaveOpen: true });
+
+  // Test the initial states.
+  let cacheUsage = await SiteDataManager.getCacheSize();
+  let quotaUsage = await SiteDataTestUtils.getQuotaUsage(
+    TEST_QUOTA_USAGE_ORIGIN
+  );
+  let totalUsage = await SiteDataManager.getTotalUsage();
+  Assert.greater(cacheUsage, 0, "The cache usage should not be 0");
+  Assert.greater(quotaUsage, 0, "The quota usage should not be 0");
+  Assert.greater(totalUsage, 0, "The total usage should not be 0");
+
+  let initialSizeLabelValue = await SpecialPowers.spawn(
+    gBrowser.selectedBrowser,
+    [],
+    async function () {
+      let sizeLabel = content.document.getElementById("totalSiteDataSize");
+      return sizeLabel.textContent;
+    }
+  );
+
+  let doc = gBrowser.selectedBrowser.contentDocument;
+  let clearSiteDataButton = doc.getElementById("clearSiteDataButton");
+
+  let url = "chrome://browser/content/sanitize_v2.xhtml";
+  let dialogOpened = promiseLoadSubDialog(url);
+  clearSiteDataButton.doCommand();
+  let dialogWin = await dialogOpened;
+
+  // Convert the usage numbers in the same way the UI does it to assert
+  // that they're displayed in the dialog.
+  let [convertedTotalUsage] = DownloadUtils.convertByteUnits(totalUsage);
+  // For cache we just assert that the right unit (KB, probably) is displayed,
+  // since we've had cache intermittently changing under our feet.
+  let [, convertedCacheUnit] = DownloadUtils.convertByteUnits(cacheUsage);
+
+  let cookiesCheckboxId = "cookiesAndStorage";
+  let cacheCheckboxId = "cache";
+  let clearSiteDataCheckbox =
+    dialogWin.document.getElementById(cookiesCheckboxId);
+  let clearCacheCheckbox = dialogWin.document.getElementById(cacheCheckboxId);
+  // The usage details are filled asynchronously, so we assert that they're present by
+  // waiting for them to be filled in.
+  await Promise.all([
+    TestUtils.waitForCondition(
+      () =>
+        clearSiteDataCheckbox.label &&
+        clearSiteDataCheckbox.label.includes(convertedTotalUsage),
+      "Should show the quota usage"
+    ),
+    TestUtils.waitForCondition(
+      () =>
+        clearCacheCheckbox.label &&
+        clearCacheCheckbox.label.includes(convertedCacheUnit),
+      "Should show the cache usage"
+    ),
+  ]);
+
+  // Check the boxes according to our test input.
+  clearSiteDataCheckbox.checked = clearSiteData;
+  clearCacheCheckbox.checked = clearCache;
+
+  // select clear everything to match the old dialog boxes behaviour for this test
+  let timespanSelection = dialogWin.document.getElementById(
+    "sanitizeDurationChoice"
+  );
+  timespanSelection.value = 1;
+
+  // Some additional promises/assertions to wait for
+  // when deleting site data.
+  let updatePromise;
+  if (clearSiteData) {
+    // the new clear history dialog does not have a extra prompt
+    // to clear site data after clicking clear
+    updatePromise = promiseSiteDataManagerSitesUpdated();
+  }
+
+  let dialogClosed = BrowserTestUtils.waitForEvent(dialogWin, "unload");
+
+  let clearButton = dialogWin.document
+    .querySelector("dialog")
+    .getButton("accept");
+  let cancelButton = dialogWin.document
+    .querySelector("dialog")
+    .getButton("cancel");
+
+  if (!clearSiteData && !clearCache) {
+    // Cancel, since we can't delete anything.
+    cancelButton.click();
+  } else {
+    // Delete stuff!
+    clearButton.click();
+  }
+
+  await dialogClosed;
+
+  if (clearCache) {
+    TestUtils.waitForCondition(async function () {
+      let usage = await SiteDataManager.getCacheSize();
+      return usage == 0;
+    }, "The cache usage should be removed");
+  } else {
+    Assert.greater(
+      await SiteDataManager.getCacheSize(),
+      0,
+      "The cache usage should not be 0"
+    );
+  }
+
+  if (clearSiteData) {
+    await updatePromise;
+    await promiseServiceWorkersCleared();
+
+    TestUtils.waitForCondition(async function () {
+      let usage = await SiteDataManager.getTotalUsage();
+      return usage == 0;
+    }, "The total usage should be removed");
+  } else {
+    quotaUsage = await SiteDataTestUtils.getQuotaUsage(TEST_QUOTA_USAGE_ORIGIN);
+    totalUsage = await SiteDataManager.getTotalUsage();
+    Assert.greater(quotaUsage, 0, "The quota usage should not be 0");
+    Assert.greater(totalUsage, 0, "The total usage should not be 0");
+  }
+
+  if (clearCache || clearSiteData) {
+    // Check that the size label in about:preferences updates after we cleared data.
+    await SpecialPowers.spawn(
+      gBrowser.selectedBrowser,
+      [{ initialSizeLabelValue }],
+      async function (opts) {
+        let sizeLabel = content.document.getElementById("totalSiteDataSize");
+        await ContentTaskUtils.waitForCondition(
+          () => sizeLabel.textContent != opts.initialSizeLabelValue,
+          "Site data size label should have updated."
+        );
+      }
+    );
+  }
+
+  let permission = PermissionTestUtils.getPermissionObject(
+    TEST_QUOTA_USAGE_ORIGIN,
+    "persistent-storage"
+  );
+  is(
+    clearSiteData ? permission : permission.capability,
+    clearSiteData ? null : Services.perms.ALLOW_ACTION,
+    "Should have the correct permission state."
+  );
+
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+  await SiteDataManager.removeAll();
+}
+
+add_setup(function () {
+  SpecialPowers.pushPrefEnv({
+    set: [["privacy.sanitize.useOldClearHistoryDialog", false]],
+  });
+
+  // The tests in this file all test specific interactions with the new clear
+  // history dialog and can't be split up.
+  requestLongerTimeout(2);
+});
+
+// Test opening the "Clear All Data" dialog and cancelling.
+add_task(async function testNoSiteDataNoCacheClearing() {
+  await testClearData(false, false);
+});
+
+// Test opening the "Clear All Data" dialog and removing all site data.
+add_task(async function testSiteDataClearing() {
+  await testClearData(true, false);
+});
+
+// Test opening the "Clear All Data" dialog and removing all cache.
+add_task(async function testCacheClearing() {
+  await testClearData(false, true);
+});
+
+// Test opening the "Clear All Data" dialog and removing everything.
+add_task(async function testSiteDataAndCacheClearing() {
+  await testClearData(true, true);
+});
+
+// Test clearing persistent storage
+add_task(async function testPersistentStorage() {
+  PermissionTestUtils.add(
+    TEST_QUOTA_USAGE_ORIGIN,
+    "persistent-storage",
+    Services.perms.ALLOW_ACTION
+  );
+
+  await openPreferencesViaOpenPreferencesAPI("privacy", { leaveOpen: true });
+
+  let doc = gBrowser.selectedBrowser.contentDocument;
+  let clearSiteDataButton = doc.getElementById("clearSiteDataButton");
+
+  let url = "chrome://browser/content/sanitize_v2.xhtml";
+  let dialogOpened = promiseLoadSubDialog(url);
+  clearSiteDataButton.doCommand();
+  let dialogWin = await dialogOpened;
+  let dialogClosed = BrowserTestUtils.waitForEvent(dialogWin, "unload");
+
+  let timespanSelection = dialogWin.document.getElementById(
+    "sanitizeDurationChoice"
+  );
+  timespanSelection.value = 1;
+  let clearButton = dialogWin.document
+    .querySelector("dialog")
+    .getButton("accept");
+  clearButton.click();
+  await dialogClosed;
+
+  let permission = PermissionTestUtils.getPermissionObject(
+    TEST_QUOTA_USAGE_ORIGIN,
+    "persistent-storage"
+  );
+  is(permission, null, "Should have the correct permission state.");
+
+  BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
diff --git a/browser/components/preferences/translations.inc.xhtml b/browser/components/preferences/translations.inc.xhtml
index 9463fde707..1143cbc6d0 100644
--- a/browser/components/preferences/translations.inc.xhtml
+++ b/browser/components/preferences/translations.inc.xhtml
@@ -19,45 +19,63 @@
 
   <p id="translations-settings-description" data-l10n-id="translations-settings-description"/>
 
-  <div class="translations-settings-manage-list"
-       id="translations-settings-manage-always-translate-list">
+  <moz-card class="translations-settings-manage-section" data-l10n-attrs="heading"
+       id="translations-settings-always-translate-section">
     <div class="translations-settings-manage-language">
       <h2 id="translations-settings-always-translate" data-l10n-id="translations-settings-always-translate"/>
       <xul:menulist id="translations-settings-always-translate-list"
-                    data-l10n-id="translations-settings-add-language-button">
-        <xul:menupopup/>
+                    data-l10n-id="translations-settings-add-language-button"
+                    aria-labelledby="translations-settings-always-translate">
+        <!-- The list of <menuitem> will be dynamically inserted. -->
+        <xul:menupopup id="translations-settings-always-translate-popup"/>
       </xul:menulist>
     </div>
-  </div>
+  </moz-card>
 
-  <div id="translations-settings-manage-never-translate-list"
-       class="translations-settings-manage-list">
+  <moz-card id="translations-settings-never-translate-section"
+       class="translations-settings-manage-section">
     <div class="translations-settings-manage-language">
       <h2 id="translations-settings-never-translate" data-l10n-id="translations-settings-never-translate"/>
       <xul:menulist id="translations-settings-never-translate-list"
-                    data-l10n-id="translations-settings-add-language-button">
-        <xul:menupopup/>
+                    data-l10n-id="translations-settings-add-language-button"
+                    aria-labelledby="translations-settings-never-translate">
+        <!-- The list of <menuitem> will be dynamically inserted. -->
+        <xul:menupopup id="translations-settings-never-translate-popup"/>
       </xul:menulist>
     </div>
-  </div>
+  </moz-card>
 
-  <div id="translations-settings-never-sites-list" class="translations-settings-manage-list" >
-    <div class="translations-settings-manage-list-info" >
+  <moz-card id="translations-settings-never-sites-section"
+            class="translations-settings-manage-section">
+    <div class="translations-settings-manage-section-info" >
       <h2 id="translations-settings-never-sites-header"
           data-l10n-id="translations-settings-never-sites-header"/>
       <p id="translations-settings-never-sites"
          data-l10n-id="translations-settings-never-sites-description"/>
     </div>
-  </div>
+  </moz-card>
 
-  <div id="translations-settings-manage-install-list" class="translations-settings-manage-list">
-    <div class="translations-settings-manage-list-info">
-      <h2 id="translations-settings-download-languages"
-          data-l10n-id="translations-settings-download-languages"/>
+  <moz-card id="translations-settings-download-section"
+       class="translations-settings-manage-section">
+    <div class="translations-settings-manage-section-info">
+      <h2 data-l10n-id="translations-settings-download-languages"/>
       <a is="moz-support-link" class="learnMore"
           id="download-languages-learn-more"
           data-l10n-id="translations-settings-download-languages-link"
           support-page="website-translation"/>
     </div>
-  </div>
+    <div class="translations-settings-languages-card">
+      <h3 class="translations-settings-language-header" data-l10n-id="translations-settings-language-header"></h3>
+      <div class="translations-settings-language-list">
+        <div class="translations-settings-language">
+          <moz-button class="translations-settings-download-icon" type="ghost icon"
+                      aria-label="translations-settings-download-all-languages"></moz-button>
+          <!--  The option to "All languages" is added here.
+                In translations.js the option to download individual languages is
+                added dynamically based on the supported language list -->
+          <label id="translations-settings-download-all-languages" data-l10n-id="translations-settings-download-all-languages"></label>
+        </div>
+      </div>
+    </div>
+  </moz-card>
 </div>
diff --git a/browser/components/preferences/translations.js b/browser/components/preferences/translations.js
index c9cfe472ac..1bfa021d59 100644
--- a/browser/components/preferences/translations.js
+++ b/browser/components/preferences/translations.js
@@ -4,6 +4,10 @@
 
 /* import-globals-from preferences.js */
 
+ChromeUtils.defineESModuleGetters(this, {
+  TranslationsParent: "resource://gre/actors/TranslationsParent.sys.mjs",
+});
+
 let gTranslationsPane = {
   init() {
     document
@@ -11,5 +15,271 @@ let gTranslationsPane = {
       .addEventListener("click", function () {
         gotoPref("general");
       });
+
+    document
+      .getElementById("translations-settings-always-translate-list")
+      .addEventListener("command", this.addAlwaysLanguage);
+
+    document
+      .getElementById("translations-settings-never-translate-list")
+      .addEventListener("command", this.addNeverLanguage);
+
+    this.buildLanguageDropDowns();
+    this.buildDownloadLanguageList();
+  },
+
+  /**
+   * Populate the Drop down list with the list of supported languages
+   * for the user to choose languages to add to Always translate and
+   * Never translate settings list.
+   */
+  async buildLanguageDropDowns() {
+    const { fromLanguages } = await TranslationsParent.getSupportedLanguages();
+    let alwaysLangPopup = document.getElementById(
+      "translations-settings-always-translate-popup"
+    );
+    let neverLangPopup = document.getElementById(
+      "translations-settings-never-translate-popup"
+    );
+
+    for (const { langTag, displayName } of fromLanguages) {
+      const alwaysLang = document.createXULElement("menuitem");
+      alwaysLang.setAttribute("value", langTag);
+      alwaysLang.setAttribute("label", displayName);
+      alwaysLangPopup.appendChild(alwaysLang);
+      const neverLang = document.createXULElement("menuitem");
+      neverLang.setAttribute("value", langTag);
+      neverLang.setAttribute("label", displayName);
+      neverLangPopup.appendChild(neverLang);
+    }
+  },
+
+  /**
+   * Show a list of languages for the user to be able to install
+   * and uninstall language models for local translation.
+   */
+  async buildDownloadLanguageList() {
+    const supportedLanguages = await TranslationsParent.getSupportedLanguages();
+    const languageList = TranslationsParent.getLanguageList(supportedLanguages);
+
+    let installList = document.querySelector(
+      ".translations-settings-language-list"
+    );
+
+    // The option to download "All languages" is added in xhtml.
+    // Here the option to download individual languages is dynamically added
+    // based on the supported language list
+    installList
+      .querySelector("moz-button")
+      .addEventListener("click", installLanguage);
+
+    for (const language of languageList) {
+      const languageElement = document.createElement("div");
+      languageElement.classList.add("translations-settings-language");
+
+      const languageLabel = document.createElement("label");
+      languageLabel.textContent = language.displayName;
+      languageLabel.setAttribute("value", language.langTag);
+      // Using the language tag suffix to create unique id for each language
+      languageLabel.id = "translations-settings-download-" + language.langTag;
+
+      const installButton = document.createElement("moz-button");
+      installButton.classList.add("translations-settings-download-icon");
+      installButton.setAttribute("type", "ghost icon");
+      installButton.addEventListener("click", installLanguage);
+      installButton.setAttribute("aria-label", languageLabel.id);
+
+      languageElement.appendChild(installButton);
+      languageElement.appendChild(languageLabel);
+      installList.appendChild(languageElement);
+    }
+  },
+
+  /**
+   * Event handler when the user wants to add a language to
+   * Always translate settings list.
+   */
+  addAlwaysLanguage(event) {
+    /* TODO:
+    The function addLanguage adds the HTML element.
+    It will be moved to the observer in the next Bug - 1881259 .
+    It is here just to test the UI.
+    For now a language can be added multiple times.
+
+    In the next bug we will maintain a local state of preferences.
+    When a language is added or removed, the user event updates the preferences in the Services,
+    This triggers the observer which compares the preferences in the local state and the
+    preferences in the Services and adds or removes the language in the local state and updates the
+     UI to reflect the updated Preferences in the Services.
+    */
+    addLanguage(
+      event,
+      "translations-settings-always-translate-section",
+      deleteAlwaysLanguage
+    );
+  },
+
+  /**
+   * Event handler when the user wants to add a language to
+   * Never translate settings list.
+   */
+  addNeverLanguage(event) {
+    /* TODO:
+    The function addLanguage adds the HTML element.
+    It will be moved to the observer in the next Bug - 1881259 .
+    It is here just to test the UI.
+    For now a language can be added multiple times.
+
+    In the next bug we will maintain a local state of preferences.
+    When a language is added or removed, the user event updates the preferences in the Services,
+    This triggers the observer which compares the preferences in the local state and the
+    preferences in the Services and adds or removes the language in the local state and updates the
+     UI to reflect the updated Preferences in the Services.
+    */
+    addLanguage(
+      event,
+      "translations-settings-never-translate-section",
+      deleteNeverLanguage
+    );
   },
 };
+
+/**
+ * Function to add a language selected by the user to the list of
+ * Always/Never translate settings list.
+ */
+async function addLanguage(event, listClass, delHandler) {
+  const translatePrefix =
+    listClass === "translations-settings-never-translate-section"
+      ? "never"
+      : "always";
+  let translateSection = document.getElementById(listClass);
+  let languageList = translateSection.querySelector(
+    ".translations-settings-language-list"
+  );
+
+  // While adding the first language, add the Header and language List div
+  if (!languageList) {
+    let languageCard = document.createElement("div");
+    languageCard.classList.add("translations-settings-languages-card");
+    translateSection.appendChild(languageCard);
+
+    let languageHeader = document.createElement("h3");
+    languageCard.appendChild(languageHeader);
+    languageHeader.setAttribute(
+      "data-l10n-id",
+      "translations-settings-language-header"
+    );
+    languageHeader.classList.add("translations-settings-language-header");
+
+    languageList = document.createElement("div");
+    languageList.classList.add("translations-settings-language-list");
+    languageCard.appendChild(languageList);
+  }
+  const languageElement = document.createElement("div");
+  languageElement.classList.add("translations-settings-language");
+  // Add the language after the Language Header
+  languageList.insertBefore(languageElement, languageList.firstChild);
+
+  const languageLabel = document.createElement("label");
+  languageLabel.textContent = event.target.getAttribute("label");
+  languageLabel.setAttribute("value", event.target.getAttribute("value"));
+  // Using the language tag suffix to create unique id for each language
+  // add prefix for the always/never translate
+  languageLabel.id =
+    "translations-settings-language-" +
+    translatePrefix +
+    "-" +
+    event.target.getAttribute("value");
+
+  const delButton = document.createElement("moz-button");
+  delButton.classList.add("translations-settings-delete-icon");
+  delButton.setAttribute("type", "ghost icon");
+  delButton.addEventListener("click", delHandler);
+  delButton.setAttribute("aria-label", languageLabel.id);
+
+  languageElement.appendChild(delButton);
+  languageElement.appendChild(languageLabel);
+
+  /*  After a language is selected the menulist button display will be set to the
+      selected langauge. After processing the button event the
+      data-l10n-id of the menulist button is restored to "Add Language" */
+  const menuList = translateSection.querySelector("menulist");
+  await document.l10n.translateElements([menuList]);
+}
+
+/**
+ * Event Handler to delete a language selected by the user from the list of
+ * Always translate settings list.
+ */
+function deleteAlwaysLanguage(event) {
+  /* TODO:
+  The function removeLanguage removes the HTML element.
+  It will be moved to the observer in the next Bug - 1881259 .
+  It is here just to test the UI.
+
+  In the next bug we will maintain a local state of preferences.
+  When a language is added or removed, the user event updates the preferences in the Services,
+  This triggers the observer which compares the preferences in the local state and the
+  preferences in the Services and adds or removes the language in the local state and updates the
+    UI to reflect the updated Preferences in the Services.
+    */
+  removeLanguage(event);
+}
+
+/**
+ * Event Handler to delete a language selected by the user from the list of
+ * Never translate settings list.
+ */
+function deleteNeverLanguage(event) {
+  /* TODO:
+  The function removeLanguage removes the HTML element.
+  It will be moved to the observer in the next Bug - 1881259 .
+  It is here just to test the UI.
+
+  In the next bug we will maintain a local state of preferences.
+  When a language is added or removed, the user event updates the preferences in the Services,
+  This triggers the observer which compares the preferences in the local state and the
+  preferences in the Services and adds or removes the language in the local state and updates the
+    UI to reflect the updated Preferences in the Services.
+  */
+  removeLanguage(event);
+}
+
+/**
+ * Function to delete a language selected by the user from the list of
+ * Always/Never translate settings list.
+ */
+function removeLanguage(event) {
+  /* Langauge section moz-card -parent of-> Language card -parent of->
+  Language heading and Language list -parent of->
+  Language Element -parent of-> language button and label
+  */
+  let languageCard = event.target.parentNode.parentNode.parentNode;
+  event.target.parentNode.remove();
+  if (languageCard.children[1].childElementCount === 0) {
+    // If there is no language in the list remove the
+    // Language Header and language list div
+    languageCard.remove();
+  }
+}
+
+/**
+ * Event Handler to install a language model selected by the user
+ */
+function installLanguage(event) {
+  event.target.classList.remove("translations-settings-download-icon");
+  event.target.classList.add("translations-settings-delete-icon");
+  event.target.removeEventListener("click", installLanguage);
+  event.target.addEventListener("click", unInstallLanguage);
+}
+
+/**
+ * Event Handler to install a language model selected by the user
+ */
+function unInstallLanguage(event) {
+  event.target.classList.remove("translations-settings-delete-icon");
+  event.target.classList.add("translations-settings-download-icon");
+  event.target.removeEventListener("click", unInstallLanguage);
+  event.target.addEventListener("click", installLanguage);
+}