Merging upstream version 127.0.

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

38 files changed, 945 insertions, 421 deletions

diff --git a/browser/base/content/test/about/browser.toml b/browser/base/content/test/about/browser.toml
index 98961200a0..2c6dafb4dd 100644
--- a/browser/base/content/test/about/browser.toml
+++ b/browser/base/content/test/about/browser.toml
@@ -66,7 +66,6 @@ support-files = [
 ["browser_aboutNewTab_bookmarksToolbar.js"]
 
 ["browser_aboutNewTab_bookmarksToolbarEmpty.js"]
-fail-if = ["a11y_checks"] # Bug 1854233 text-link may not be focusable
 skip-if = ["tsan"] # Bug 1676326, highly frequent on TSan
 
 ["browser_aboutNewTab_bookmarksToolbarNewWindow.js"]
diff --git a/browser/base/content/test/about/browser_aboutNetError_csp_iframe.js b/browser/base/content/test/about/browser_aboutNetError_csp_iframe.js
index c8028a4cf4..d245d0cd3c 100644
--- a/browser/base/content/test/about/browser_aboutNetError_csp_iframe.js
+++ b/browser/base/content/test/about/browser_aboutNetError_csp_iframe.js
@@ -8,6 +8,10 @@ const BLOCKED_PAGE =
   "http://example.org:8000/browser/browser/base/content/test/about/csp_iframe.sjs";
 
 add_task(async function test_csp() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["security.xfocsp.hideOpenInNewWindow", false]],
+  });
+
   let { iframePageTab, blockedPageTab } = await setupPage(
     "iframe_page_csp.html",
     BLOCKED_PAGE
diff --git a/browser/base/content/test/about/browser_aboutNetError_xfo_iframe.js b/browser/base/content/test/about/browser_aboutNetError_xfo_iframe.js
index f5fd240643..2373bd8b50 100644
--- a/browser/base/content/test/about/browser_aboutNetError_xfo_iframe.js
+++ b/browser/base/content/test/about/browser_aboutNetError_xfo_iframe.js
@@ -8,6 +8,10 @@ const BLOCKED_PAGE =
   "http://example.org:8000/browser/browser/base/content/test/about/xfo_iframe.sjs";
 
 add_task(async function test_xfo_iframe() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["security.xfocsp.hideOpenInNewWindow", false]],
+  });
+
   let { iframePageTab, blockedPageTab } = await setupPage(
     "iframe_page_xfo.html",
     BLOCKED_PAGE
diff --git a/browser/base/content/test/alerts/browser.toml b/browser/base/content/test/alerts/browser.toml
index d0d56f7392..aaca2ba7dc 100644
--- a/browser/base/content/test/alerts/browser.toml
+++ b/browser/base/content/test/alerts/browser.toml
@@ -19,10 +19,6 @@ skip-if = ["os == 'win'"] # Bug 1411118
 https_first_disabled = true
 skip-if = ["os == 'win'"] # Bug 1411118
 
-["browser_notification_replace.js"]
-https_first_disabled = true
-skip-if = ["os == 'win'"] # Bug 1422928
-
 ["browser_notification_tab_switching.js"]
 https_first_disabled = true
 skip-if = ["os == 'win'"] # Bug 1243263
diff --git a/browser/base/content/test/alerts/browser_notification_close.js b/browser/base/content/test/alerts/browser_notification_close.js
index 7568f1cc2d..3fd50bed5b 100644
--- a/browser/base/content/test/alerts/browser_notification_close.js
+++ b/browser/base/content/test/alerts/browser_notification_close.js
@@ -21,17 +21,16 @@ add_task(async function test_notificationClose() {
   Services.prefs.setBoolPref("alerts.showFavicons", true);
 
   await PlacesTestUtils.addVisits(notificationURI);
-  let faviconURI = await new Promise(resolve => {
-    let uri = makeURI(
-      "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC"
-    );
-    PlacesUtils.favicons.setAndFetchFaviconForPage(
+  let dataURL = makeURI(
+    "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVQI12P4//8/AAX+Av7czFnnAAAAAElFTkSuQmCC"
+  );
+  await new Promise(resolve => {
+    PlacesUtils.favicons.setFaviconForPage(
       notificationURI,
-      uri,
-      true,
-      PlacesUtils.favicons.FAVICON_LOAD_NON_PRIVATE,
-      uriResult => resolve(uriResult),
-      Services.scriptSecurityManager.getSystemPrincipal()
+      dataURL,
+      dataURL,
+      null,
+      resolve
     );
   });
 
@@ -67,11 +66,7 @@ add_task(async function test_notificationClose() {
         "Body text of notification should be present"
       );
       let alertIcon = alertWindow.document.getElementById("alertIcon");
-      is(
-        alertIcon.src,
-        faviconURI.spec,
-        "Icon of notification should be present"
-      );
+      is(alertIcon.src, dataURL.spec, "Icon of notification should be present");
 
       let alertCloseButton = alertWindow.document.querySelector(".close-icon");
       is(alertCloseButton.localName, "toolbarbutton", "close button found");
diff --git a/browser/base/content/test/alerts/browser_notification_replace.js b/browser/base/content/test/alerts/browser_notification_replace.js
deleted file mode 100644
index 9c72e90ab1..0000000000
--- a/browser/base/content/test/alerts/browser_notification_replace.js
+++ /dev/null
@@ -1,66 +0,0 @@
-"use strict";
-
-let notificationURL =
-  // eslint-disable-next-line @microsoft/sdl/no-insecure-url
-  "http://example.org/browser/browser/base/content/test/alerts/file_dom_notifications.html";
-
-add_task(async function test_notificationReplace() {
-  await addNotificationPermission(notificationURL);
-
-  await BrowserTestUtils.withNewTab(
-    {
-      gBrowser,
-      url: notificationURL,
-    },
-    async function dummyTabTask(aBrowser) {
-      await SpecialPowers.spawn(aBrowser, [], async function () {
-        let win = content.window.wrappedJSObject;
-        let notification = win.showNotification1();
-        let promiseCloseEvent = ContentTaskUtils.waitForEvent(
-          notification,
-          "close"
-        );
-
-        let showEvent = await ContentTaskUtils.waitForEvent(
-          notification,
-          "show"
-        );
-        Assert.equal(
-          showEvent.target.body,
-          "Test body 1",
-          "Showed tagged notification"
-        );
-
-        let newNotification = win.showNotification2();
-        let newShowEvent = await ContentTaskUtils.waitForEvent(
-          newNotification,
-          "show"
-        );
-        Assert.equal(
-          newShowEvent.target.body,
-          "Test body 2",
-          "Showed new notification with same tag"
-        );
-
-        let closeEvent = await promiseCloseEvent;
-        Assert.equal(
-          closeEvent.target.body,
-          "Test body 1",
-          "Closed previous tagged notification"
-        );
-
-        let promiseNewCloseEvent = ContentTaskUtils.waitForEvent(
-          newNotification,
-          "close"
-        );
-        newNotification.close();
-        let newCloseEvent = await promiseNewCloseEvent;
-        Assert.equal(
-          newCloseEvent.target.body,
-          "Test body 2",
-          "Closed new notification"
-        );
-      });
-    }
-  );
-});
diff --git a/browser/base/content/test/contextMenu/browser.toml b/browser/base/content/test/contextMenu/browser.toml
index 660f6a955b..c7af1bc437 100644
--- a/browser/base/content/test/contextMenu/browser.toml
+++ b/browser/base/content/test/contextMenu/browser.toml
@@ -101,3 +101,5 @@ support-files = [
   "test_view_image_inline_svg.html",
 ]
 skip-if = ["os == 'linux' && socketprocess_networking"]
+
+["browser_contextmenu_cross_boundary_selection.js"]
diff --git a/browser/base/content/test/contextMenu/browser_contextmenu.js b/browser/base/content/test/contextMenu/browser_contextmenu.js
index 00da3113c6..d8dc0ab5e0 100644
--- a/browser/base/content/test/contextMenu/browser_contextmenu.js
+++ b/browser/base/content/test/contextMenu/browser_contextmenu.js
@@ -41,6 +41,10 @@ let hasContainers =
   Services.prefs.getBoolPref("privacy.userContext.enabled") &&
   ContextualIdentityService.getPublicIdentities().length;
 
+const hasSelectTranslations =
+  Services.prefs.getBoolPref("browser.translations.enable") &&
+  Services.prefs.getBoolPref("browser.translations.select.enable");
+
 const example_base =
   // eslint-disable-next-line @microsoft/sdl/no-insecure-url
   "http://example.com/browser/browser/base/content/test/contextMenu/";
@@ -112,6 +116,7 @@ add_task(async function test_xul_text_link_label() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   // Clean up so won't affect HTML element test cases.
@@ -204,6 +209,7 @@ const kLinkItems = [
   true,
   "context-searchselect-private",
   true,
+  ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
 ];
 
 add_task(async function test_link() {
@@ -234,6 +240,7 @@ add_task(async function test_mailto() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 });
 
@@ -247,6 +254,7 @@ add_task(async function test_tel() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 });
 
@@ -273,6 +281,10 @@ add_task(async function test_image() {
         null,
         "context-setDesktopBackground",
         true,
+        "---",
+        null,
+        "context-take-screenshot",
+        true,
       ],
       {
         onContextMenuShown() {
@@ -356,6 +368,10 @@ add_task(async function test_video_ok() {
     true,
     "context-sendvideo",
     true,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -404,6 +420,10 @@ add_task(async function test_video_ok() {
     true,
     "context-sendvideo",
     true,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -490,6 +510,10 @@ add_task(async function test_video_bad() {
     true,
     "context-sendvideo",
     true,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -538,6 +562,10 @@ add_task(async function test_video_bad() {
     true,
     "context-sendvideo",
     true,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -588,6 +616,10 @@ add_task(async function test_video_bad2() {
     false,
     "context-sendvideo",
     false,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -636,6 +668,10 @@ add_task(async function test_video_bad2() {
     false,
     "context-sendvideo",
     false,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 
   await SpecialPowers.popPrefEnv();
@@ -767,6 +803,10 @@ add_task(async function test_video_in_iframe() {
       true,
       "---",
       null,
+      "context-take-frame-screenshot",
+      true,
+      "---",
+      null,
       "context-viewframeinfo",
       true,
     ]),
@@ -846,6 +886,10 @@ add_task(async function test_video_in_iframe() {
       true,
       "---",
       null,
+      "context-take-frame-screenshot",
+      true,
+      "---",
+      null,
       "context-viewframeinfo",
       true,
     ]),
@@ -967,6 +1011,10 @@ add_task(async function test_image_in_iframe() {
       true,
       "---",
       null,
+      "context-take-frame-screenshot",
+      true,
+      "---",
+      null,
       "context-viewframeinfo",
       true,
     ]),
@@ -1336,6 +1384,7 @@ add_task(async function test_select_text() {
       true,
       "context-searchselect-private",
       true,
+      ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
       "---",
       null,
       "context-viewpartialsource-selection",
@@ -1369,6 +1418,9 @@ add_task(async function test_select_text_search_service_not_initialized() {
       null,
       "context-take-screenshot",
       true,
+      ...(hasSelectTranslations
+        ? ["---", null, "context-translate-selection", true]
+        : []),
       "---",
       null,
       "context-viewpartialsource-selection",
@@ -1423,6 +1475,7 @@ add_task(async function test_select_text_link() {
       true,
       "context-searchselect-private",
       true,
+      ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
       "---",
       null,
       "context-viewpartialsource-selection",
@@ -1490,6 +1543,9 @@ add_task(async function test_imagelink() {
     null,
     "context-setDesktopBackground",
     true,
+    ...(hasSelectTranslations
+      ? ["---", null, "context-translate-selection", true]
+      : []),
   ]);
 });
 
@@ -1591,6 +1647,10 @@ add_task(async function test_longdesc() {
     null,
     "context-setDesktopBackground",
     true,
+    "---",
+    null,
+    "context-take-screenshot",
+    true,
   ]);
 });
 
@@ -1682,6 +1742,7 @@ add_task(async function test_svg_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   await test_contextmenu("#svg-with-link2 > a", [
@@ -1711,6 +1772,7 @@ add_task(async function test_svg_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   await test_contextmenu("#svg-with-link3 > a", [
@@ -1740,6 +1802,7 @@ add_task(async function test_svg_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 });
 
@@ -1771,6 +1834,7 @@ add_task(async function test_svg_relative_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   await test_contextmenu("#svg-with-relative-link2 > a", [
@@ -1800,6 +1864,7 @@ add_task(async function test_svg_relative_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   await test_contextmenu("#svg-with-relative-link3 > a", [
@@ -1829,6 +1894,7 @@ add_task(async function test_svg_relative_link() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 });
 
@@ -1898,6 +1964,7 @@ add_task(async function test_background_image() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   // Don't show image related context menu commands when there is a selection
@@ -1921,6 +1988,7 @@ add_task(async function test_background_image() {
       true,
       "context-searchselect-private",
       true,
+      ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
       "---",
       null,
       "context-viewpartialsource-selection",
@@ -1989,6 +2057,7 @@ add_task(async function test_strip_on_share_on_secure_about_page() {
     true,
     "context-searchselect-private",
     true,
+    ...(hasSelectTranslations ? ["context-translate-selection", true] : []),
   ]);
 
   // Clean up
diff --git a/browser/base/content/test/contextMenu/browser_contextmenu_cross_boundary_selection.js b/browser/base/content/test/contextMenu/browser_contextmenu_cross_boundary_selection.js
new file mode 100644
index 0000000000..3137a1e136
--- /dev/null
+++ b/browser/base/content/test/contextMenu/browser_contextmenu_cross_boundary_selection.js
@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const PAGE = `
+  data:text/html,
+  <div>OuterText<div>
+  <div id="host">
+    <template shadowrootmode="open">
+      <span id="innerText">InnerText</span>
+    </template>
+  </div>
+  `;
+/**
+ * Tests that right click on a cross boundary selection shows the context menu
+ */
+add_task(async function () {
+  await SpecialPowers.pushPrefEnv({
+    set: [["dom.shadowdom.selection_across_boundary.enabled", true]],
+  });
+  await BrowserTestUtils.withNewTab(
+    {
+      gBrowser,
+      url: PAGE,
+    },
+    async function (browser) {
+      let contextMenu = document.getElementById("contentAreaContextMenu");
+      let awaitPopupShown = BrowserTestUtils.waitForEvent(
+        contextMenu,
+        "popupshown"
+      );
+
+      let awaitPopupHidden = BrowserTestUtils.waitForEvent(
+        contextMenu,
+        "popuphidden"
+      );
+
+      await SpecialPowers.spawn(browser, [], () => {
+        let host = content.document.getElementById("host");
+        content.getSelection().setBaseAndExtent(
+          content.document.body,
+          0,
+          host.shadowRoot.getElementById("innerText").firstChild,
+          3 // Only select the first three characters of the inner text
+        );
+      });
+
+      await BrowserTestUtils.synthesizeMouseAtCenter(
+        "div", // Click on the div for OuterText
+        {
+          type: "contextmenu",
+          button: 2,
+        },
+        browser
+      );
+
+      await awaitPopupShown;
+
+      const allVisibleMenuItems = Array.from(contextMenu.children)
+        .filter(elem => {
+          return !elem.hidden;
+        })
+        .map(elem => elem.id);
+
+      ok(
+        allVisibleMenuItems.includes("context-copy"),
+        "copy button should exist"
+      );
+
+      contextMenu.hidePopup();
+      await awaitPopupHidden;
+    }
+  );
+});
diff --git a/browser/base/content/test/contextMenu/browser_strip_on_share_link.js b/browser/base/content/test/contextMenu/browser_strip_on_share_link.js
index 435b1aa0ff..144076cfb2 100644
--- a/browser/base/content/test/contextMenu/browser_strip_on_share_link.js
+++ b/browser/base/content/test/contextMenu/browser_strip_on_share_link.js
@@ -97,6 +97,18 @@ add_task(async function testQueryParamIsNotStrippedForWrongSiteSpecific() {
   });
 });
 
+// Ensuring clean copy works with magnet links. We don't strip anything but copying the original URI should still work.
+add_task(async function testMagneticLinks() {
+  let originalUrl = "magnet:?xt=urn:btih:somesha1hash";
+  let shortenedUrl = "magnet:?xt=urn:btih:somesha1hash";
+  await testStripOnShare({
+    selectWholeUrl: true,
+    validUrl: originalUrl,
+    strippedUrl: shortenedUrl,
+    useTestList: true,
+  });
+});
+
 /**
  * Opens a new tab, opens the context menu and checks that the strip-on-share menu item is visible.
  * Checks that the stripped version of the url is copied to the clipboard.
diff --git a/browser/base/content/test/general/browser_documentnavigation.js b/browser/base/content/test/general/browser_documentnavigation.js
index 880db6110f..b68e6ec3f0 100644
--- a/browser/base/content/test/general/browser_documentnavigation.js
+++ b/browser/base/content/test/general/browser_documentnavigation.js
@@ -229,7 +229,7 @@ add_task(async function () {
   let sidebar = document.getElementById("sidebar");
 
   let loadPromise = BrowserTestUtils.waitForEvent(sidebar, "load", true);
-  SidebarUI.toggle("viewBookmarksSidebar");
+  SidebarController.toggle("viewBookmarksSidebar");
   await loadPromise;
 
   gURLBar.focus();
@@ -278,7 +278,7 @@ add_task(async function () {
     "back focus with sidebar urlbar"
   );
 
-  SidebarUI.toggle("viewBookmarksSidebar");
+  SidebarController.toggle("viewBookmarksSidebar");
 });
 
 // Navigate when the downloads panel is open
diff --git a/browser/base/content/test/performance/browser_preferences_usage.js b/browser/base/content/test/performance/browser_preferences_usage.js
index b0ff140d19..9ad9a8dde8 100644
--- a/browser/base/content/test/performance/browser_preferences_usage.js
+++ b/browser/base/content/test/performance/browser_preferences_usage.js
@@ -70,13 +70,6 @@ function checkPrefGetters(stats, max, knownProblematicPrefs = {}) {
     }
   }
 
-  // This pref will be accessed by mozJSComponentLoader when loading modules,
-  // which fails TV runs since they run the test multiple times without restarting.
-  // We just ignore this pref, since it's for testing only anyway.
-  if (knownProblematicPrefs["browser.startup.record"]) {
-    delete knownProblematicPrefs["browser.startup.record"];
-  }
-
   let unusedPrefs = Object.keys(knownProblematicPrefs);
   is(
     unusedPrefs.length,
@@ -104,18 +97,9 @@ add_task(async function startup() {
   let max = 40;
 
   let knownProblematicPrefs = {
-    "browser.startup.record": {
-      // This pref is accessed in Nighly and debug builds only.
-      min: 200,
-      max: 450,
-    },
     "network.loadinfo.skip_type_assertion": {
       // This is accessed in debug only.
     },
-    "chrome.override_package.global": {
-      min: 0,
-      max: 50,
-    },
   };
 
   let startupRecorder =
@@ -135,9 +119,6 @@ add_task(async function open_10_tabs() {
   const max = 4 * DEFAULT_PROCESS_COUNT;
 
   let knownProblematicPrefs = {
-    "browser.startup.record": {
-      max: 20,
-    },
     "browser.tabs.remote.logSwitchTiming": {
       max: 35,
     },
diff --git a/browser/base/content/test/popupNotifications/browser_popupNotification_security_delay.js b/browser/base/content/test/popupNotifications/browser_popupNotification_security_delay.js
index 140c2be2fd..3c652b26a2 100644
--- a/browser/base/content/test/popupNotifications/browser_popupNotification_security_delay.js
+++ b/browser/base/content/test/popupNotifications/browser_popupNotification_security_delay.js
@@ -44,22 +44,22 @@ add_setup(async function () {
   });
 });
 
+/**
+ * The security delay calculation in PopupNotification.sys.mjs is dependent on
+ * the monotonically increasing value of performance.now. This timestamp is
+ * not relative to a fixed date, but to runtime.
+ * We need to wait for the value performance.now() to be larger than the
+ * security delay in order to observe the bug. Only then does the
+ * timeSinceShown check in PopupNotifications.sys.mjs lead to a timeSinceShown
+ * value that is unconditionally greater than lazy.buttonDelay for
+ * notification.timeShown = null = 0.
+ * See: https://searchfox.org/mozilla-central/rev/f32d5f3949a3f4f185122142b29f2e3ab776836e/toolkit/modules/PopupNotifications.sys.mjs#1870-1872
+ *
+ * When running in automation as part of a larger test suite performance.now()
+ * should usually be already sufficiently high in which case this check should
+ * directly resolve.
+ */
 async function ensureSecurityDelayReady() {
-  /**
-   * The security delay calculation in PopupNotification.sys.mjs is dependent on
-   * the monotonically increasing value of performance.now. This timestamp is
-   * not relative to a fixed date, but to runtime.
-   * We need to wait for the value performance.now() to be larger than the
-   * security delay in order to observe the bug. Only then does the
-   * timeSinceShown check in PopupNotifications.sys.mjs lead to a timeSinceShown
-   * value that is unconditionally greater than lazy.buttonDelay for
-   * notification.timeShown = null = 0.
-   * See: https://searchfox.org/mozilla-central/rev/f32d5f3949a3f4f185122142b29f2e3ab776836e/toolkit/modules/PopupNotifications.sys.mjs#1870-1872
-   *
-   * When running in automation as part of a larger test suite performance.now()
-   * should usually be already sufficiently high in which case this check should
-   * directly resolve.
-   */
   await TestUtils.waitForCondition(
     () => performance.now() > TEST_SECURITY_DELAY,
     "Wait for performance.now() > SECURITY_DELAY",
@@ -69,73 +69,73 @@ async function ensureSecurityDelayReady() {
 }
 
 /**
- * Tests that when we show a second notification while the panel is open the
- * timeShown attribute is correctly set and the security delay is enforced
- * properly.
+ * Test helper for security delay tests which performs the following steps:
+ * 1. Shows a test notification.
+ * 2. Waits for the notification panel to be shown and checks that the initial
+ *    security delay blocks clicks.
+ * 3. Waits for the security delay to expire. Clicks should now be allowed.
+ * 4. Executes the provided onSecurityDelayExpired function. This function
+ *    should renew the security delay.
+ * 5. Tests that the security delay was renewed.
+ * 6. Ensures that after the security delay the notification can be closed.
+ *
+ * @param {*} options
+ * @param {function} options.onSecurityDelayExpired - Function to run after the
+ *  security delay has expired. This function should trigger a renew of the
+ *  security delay.
+ * @param {function} options.cleanupFn - Optional cleanup function to run after
+ * the test has completed.
+ * @returns {Promise<void>} - Resolves when the test has completed.
  */
-add_task(async function test_timeShownMultipleNotifications() {
+async function runPopupNotificationSecurityDelayTest({
+  onSecurityDelayExpired,
+  cleanupFn = () => {},
+}) {
   await ensureSecurityDelayReady();
 
-  ok(
-    !PopupNotifications.isPanelOpen,
-    "PopupNotification panel should not be open initially."
-  );
-
-  info("Open the first notification.");
+  info("Open a notification.");
   let popupShownPromise = waitForNotificationPanel();
   showNotification();
   await popupShownPromise;
   ok(
     PopupNotifications.isPanelOpen,
-    "PopupNotification should be open after first show call."
+    "PopupNotification should be open after show call."
   );
 
-  is(
-    PopupNotifications._currentNotifications.length,
-    1,
-    "There should only be one notification"
+  // Test that the initial security delay works.
+  info(
+    "Trigger main action via button click during the initial security delay."
   );
+  triggerMainCommand(PopupNotifications.panel);
 
+  await new Promise(resolve => setTimeout(resolve, 0));
+
+  ok(PopupNotifications.isPanelOpen, "PopupNotification should still be open.");
   let notification = PopupNotifications.getNotification(
     "foo",
     gBrowser.selectedBrowser
   );
-  is(notification?.id, "foo", "There should be a notification with id foo");
-  ok(notification.timeShown, "The notification should have timeShown set");
-
-  info(
-    "Call show again with the same notification id while the PopupNotification panel is still open."
-  );
-  showNotification();
   ok(
-    PopupNotifications.isPanelOpen,
-    "PopupNotification should still open after second show call."
-  );
-  notification = PopupNotifications.getNotification(
-    "foo",
-    gBrowser.selectedBrowser
-  );
-  is(
-    PopupNotifications._currentNotifications.length,
-    1,
-    "There should still only be one notification"
+    notification,
+    "Notification should still be open because we clicked during the security delay."
   );
+  // If the notification is no longer shown (test failure) skip the remaining
+  // checks.
+  if (!notification) {
+    await cleanupFn();
+    return;
+  }
 
-  is(
-    notification?.id,
-    "foo",
-    "There should still be a notification with id foo"
+  info("Wait for security delay to expire.");
+  await new Promise(resolve =>
+    // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+    setTimeout(resolve, TEST_SECURITY_DELAY + 500)
   );
-  ok(notification.timeShown, "The notification should have timeShown set");
 
-  let notificationHiddenPromise = waitForNotificationPanelHidden();
-
-  info("Trigger main action via button click during security delay");
-
-  // Wait for a tick of the event loop to ensure the button we're clicking
-  // has been slotted into moz-button-group
-  await new Promise(resolve => setTimeout(resolve, 0));
+  info("Run test specific actions which restarts the security delay.");
+  await onSecurityDelayExpired();
 
+  info("Trigger main action via button click during the new security delay.");
   triggerMainCommand(PopupNotifications.panel);
 
   await new Promise(resolve => setTimeout(resolve, 0));
@@ -149,10 +149,10 @@ add_task(async function test_timeShownMultipleNotifications() {
     notification,
     "Notification should still be open because we clicked during the security delay."
   );
-
   // If the notification is no longer shown (test failure) skip the remaining
   // checks.
   if (!notification) {
+    await cleanupFn();
     return;
   }
 
@@ -163,6 +163,7 @@ add_task(async function test_timeShownMultipleNotifications() {
   notification.timeShown = performance.now() - fakeTimeShown;
 
   info("Trigger main action via button click outside security delay");
+  let notificationHiddenPromise = waitForNotificationPanelHidden();
   triggerMainCommand(PopupNotifications.panel);
 
   info("Wait for panel to be hidden.");
@@ -170,15 +171,19 @@ add_task(async function test_timeShownMultipleNotifications() {
 
   ok(
     !PopupNotifications.getNotification("foo", gBrowser.selectedBrowser),
-    "Should not longer see the notification."
+    "Should no longer see the notification."
   );
-});
+
+  info("Cleanup.");
+  await cleanupFn();
+}
 
 /**
- * Tests that when we reshow a notification after a tab switch the timeShown
- * attribute is correctly reset and the security delay is enforced.
+ * Tests that when we show a second notification while the panel is open the
+ * timeShown attribute is correctly set and the security delay is enforced
+ * properly.
  */
-add_task(async function test_notificationReshowTabSwitch() {
+add_task(async function test_timeShownMultipleNotifications() {
   await ensureSecurityDelayReady();
 
   ok(
@@ -195,6 +200,12 @@ add_task(async function test_notificationReshowTabSwitch() {
     "PopupNotification should be open after first show call."
   );
 
+  is(
+    PopupNotifications._currentNotifications.length,
+    1,
+    "There should only be one notification"
+  );
+
   let notification = PopupNotifications.getNotification(
     "foo",
     gBrowser.selectedBrowser
@@ -202,69 +213,39 @@ add_task(async function test_notificationReshowTabSwitch() {
   is(notification?.id, "foo", "There should be a notification with id foo");
   ok(notification.timeShown, "The notification should have timeShown set");
 
-  info("Trigger main action via button click during security delay");
-  triggerMainCommand(PopupNotifications.panel);
-
-  await new Promise(resolve => setTimeout(resolve, 0));
-
-  ok(PopupNotifications.isPanelOpen, "PopupNotification should still be open.");
-  notification = PopupNotifications.getNotification(
-    "foo",
-    gBrowser.selectedBrowser
-  );
-  ok(
-    notification,
-    "Notification should still be open because we clicked during the security delay."
-  );
-
-  // If the notification is no longer shown (test failure) skip the remaining
-  // checks.
-  if (!notification) {
-    return;
-  }
-
-  let panelHiddenPromise = waitForNotificationPanelHidden();
-  let panelShownPromise;
-
-  info("Open a new tab which hides the notification panel.");
-  await BrowserTestUtils.withNewTab("https://example.com", async () => {
-    info("Wait for panel to be hidden by tab switch.");
-    await panelHiddenPromise;
-    info(
-      "Keep the tab open until the security delay for the original notification show has expired."
-    );
-    await new Promise(resolve =>
-      // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
-      setTimeout(resolve, TEST_SECURITY_DELAY + 500)
-    );
-
-    panelShownPromise = waitForNotificationPanel();
-  });
   info(
-    "Wait for the panel to show again after the tab close. We're showing the original tab again."
+    "Call show again with the same notification id while the PopupNotification panel is still open."
   );
-  await panelShownPromise;
-
+  showNotification();
   ok(
     PopupNotifications.isPanelOpen,
-    "PopupNotification should be shown after tab close."
+    "PopupNotification should still open after second show call."
   );
   notification = PopupNotifications.getNotification(
     "foo",
     gBrowser.selectedBrowser
   );
   is(
+    PopupNotifications._currentNotifications.length,
+    1,
+    "There should still only be one notification"
+  );
+
+  is(
     notification?.id,
     "foo",
     "There should still be a notification with id foo"
   );
+  ok(notification.timeShown, "The notification should have timeShown set");
 
   let notificationHiddenPromise = waitForNotificationPanelHidden();
 
-  info(
-    "Because we re-show the panel after tab close / switch the security delay should have reset."
-  );
-  info("Trigger main action via button click during the new security delay.");
+  info("Trigger main action via button click during security delay");
+
+  // Wait for a tick of the event loop to ensure the button we're clicking
+  // has been slotted into moz-button-group
+  await new Promise(resolve => setTimeout(resolve, 0));
+
   triggerMainCommand(PopupNotifications.panel);
 
   await new Promise(resolve => setTimeout(resolve, 0));
@@ -278,6 +259,7 @@ add_task(async function test_notificationReshowTabSwitch() {
     notification,
     "Notification should still be open because we clicked during the security delay."
   );
+
   // If the notification is no longer shown (test failure) skip the remaining
   // checks.
   if (!notification) {
@@ -298,109 +280,83 @@ add_task(async function test_notificationReshowTabSwitch() {
 
   ok(
     !PopupNotifications.getNotification("foo", gBrowser.selectedBrowser),
-    "Should not longer see the notification."
+    "Should no longer see the notification."
   );
 });
 
 /**
+ * Tests that when we reshow a notification after a tab switch the timeShown
+ * attribute is correctly reset and the security delay is enforced.
+ */
+add_task(async function test_notificationReshowTabSwitch() {
+  await runPopupNotificationSecurityDelayTest({
+    onSecurityDelayExpired: async () => {
+      let panelHiddenPromise = waitForNotificationPanelHidden();
+      let panelShownPromise;
+
+      info("Open a new tab which hides the notification panel.");
+      await BrowserTestUtils.withNewTab("https://example.com", async () => {
+        info("Wait for panel to be hidden by tab switch.");
+        await panelHiddenPromise;
+        panelShownPromise = waitForNotificationPanel();
+      });
+      info(
+        "Wait for the panel to show again after the tab close. We're showing the original tab again."
+      );
+      await panelShownPromise;
+
+      ok(
+        PopupNotifications.isPanelOpen,
+        "PopupNotification should be shown after tab close."
+      );
+      let notification = PopupNotifications.getNotification(
+        "foo",
+        gBrowser.selectedBrowser
+      );
+      is(
+        notification?.id,
+        "foo",
+        "There should still be a notification with id foo"
+      );
+
+      info(
+        "Because we re-show the panel after tab close / switch the security delay should have reset."
+      );
+    },
+  });
+});
+
+/**
  * Tests that the security delay gets reset when a window is repositioned and
  * the PopupNotifications panel position is updated.
  */
 add_task(async function test_notificationWindowMove() {
-  await ensureSecurityDelayReady();
-
-  info("Open a notification.");
-  let popupShownPromise = waitForNotificationPanel();
-  showNotification();
-  await popupShownPromise;
-  ok(
-    PopupNotifications.isPanelOpen,
-    "PopupNotification should be open after show call."
-  );
-
-  // Test that the initial security delay works.
-  info("Trigger main action via button click during the new security delay.");
-  triggerMainCommand(PopupNotifications.panel);
-
-  await new Promise(resolve => setTimeout(resolve, 0));
-
-  ok(PopupNotifications.isPanelOpen, "PopupNotification should still be open.");
-  let notification = PopupNotifications.getNotification(
-    "foo",
-    gBrowser.selectedBrowser
-  );
-  ok(
-    notification,
-    "Notification should still be open because we clicked during the security delay."
-  );
-  // If the notification is no longer shown (test failure) skip the remaining
-  // checks.
-  if (!notification) {
-    return;
-  }
-
-  info("Wait for security delay to expire.");
-  await new Promise(resolve =>
-    // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
-    setTimeout(resolve, TEST_SECURITY_DELAY + 500)
-  );
-
-  info("Reposition the window");
-  // Remember original window position.
-  let { screenX, screenY } = window;
-
-  let promisePopupPositioned = BrowserTestUtils.waitForEvent(
-    PopupNotifications.panel,
-    "popuppositioned"
-  );
-
-  // Move the window.
-  window.moveTo(200, 200);
-
-  // Wait for the panel to reposition and the PopupNotifications listener to run.
-  await promisePopupPositioned;
-  await new Promise(resolve => setTimeout(resolve, 0));
-
-  info("Trigger main action via button click during the new security delay.");
-  triggerMainCommand(PopupNotifications.panel);
-
-  await new Promise(resolve => setTimeout(resolve, 0));
-
-  ok(PopupNotifications.isPanelOpen, "PopupNotification should still be open.");
-  notification = PopupNotifications.getNotification(
-    "foo",
-    gBrowser.selectedBrowser
-  );
-  ok(
-    notification,
-    "Notification should still be open because we clicked during the security delay."
-  );
-  // If the notification is no longer shown (test failure) skip the remaining
-  // checks.
-  if (!notification) {
-    return;
-  }
-
-  // Ensure that once the security delay has passed the notification can be
-  // closed again.
-  let fakeTimeShown = TEST_SECURITY_DELAY + 500;
-  info(`Manually set timeShown to ${fakeTimeShown}ms in the past.`);
-  notification.timeShown = performance.now() - fakeTimeShown;
-
-  info("Trigger main action via button click outside security delay");
-  let notificationHiddenPromise = waitForNotificationPanelHidden();
-  triggerMainCommand(PopupNotifications.panel);
-
-  info("Wait for panel to be hidden.");
-  await notificationHiddenPromise;
-
-  ok(
-    !PopupNotifications.getNotification("foo", gBrowser.selectedBrowser),
-    "Should not longer see the notification."
-  );
-
-  // Reset window position
-  window.moveTo(screenX, screenY);
+  let screenX, screenY;
+
+  await runPopupNotificationSecurityDelayTest({
+    onSecurityDelayExpired: async () => {
+      info("Reposition the window");
+      // Remember original window position.
+      screenX = window.screenX;
+      screenY = window.screenY;
+
+      let promisePopupPositioned = BrowserTestUtils.waitForEvent(
+        PopupNotifications.panel,
+        "popuppositioned"
+      );
+
+      // Move the window.
+      window.moveTo(200, 200);
+
+      // Wait for the panel to reposition and the PopupNotifications listener to run.
+      await promisePopupPositioned;
+      await new Promise(resolve => setTimeout(resolve, 0));
+    },
+    cleanupFn: async () => {
+      // Reset window position
+      window.moveTo(screenX, screenY);
+    },
+  });
 });
 
 /**
@@ -563,5 +519,49 @@ add_task(async function test_notificationDuringFullScreenTransition() {
     info("Wait for full screen transition end.");
     await promiseFullScreenTransitionEnd;
     info("Full screen transition end");
+
+    await SpecialPowers.popPrefEnv();
+  });
+});
+
+/**
+ * Tests that the security delay gets extended when pointer lock is entered.
+ */
+add_task(async function test_notificationPointerLock() {
+  // We need a tab to enter pointer lock.
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    gBrowser,
+    "https://example.com"
+  );
+
+  await runPopupNotificationSecurityDelayTest({
+    onSecurityDelayExpired: async () => {
+      info("Enter pointer lock");
+      // Move focus to the browser to ensure pointer lock request succeeds.
+      gBrowser.selectedBrowser.focus();
+      let pointerLockEnterPromise = TestUtils.topicObserved(
+        "pointer-lock-entered"
+      );
+      await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async () => {
+        SpecialPowers.wrap(content.document).notifyUserGestureActivation();
+        await content.document.body.requestPointerLock();
+      });
+
+      // Wait for pointer lock to be entered and the PopupNotifications listener to run.
+      await pointerLockEnterPromise;
+      await new Promise(resolve => setTimeout(resolve, 0));
+    },
+    cleanupFn: async () => {
+      // Cleanup.
+      await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async () => {
+        SpecialPowers.wrap(content.document).notifyUserGestureActivation();
+        await content.document.exitPointerLock();
+      });
+      await TestUtils.waitForCondition(
+        () => !window.PointerLock.isActive,
+        "Wait for pointer lock exit."
+      );
+      BrowserTestUtils.removeTab(tab);
+    },
   });
 });
diff --git a/browser/base/content/test/sidebar/browser_sidebar_adopt.js b/browser/base/content/test/sidebar/browser_sidebar_adopt.js
index 344a71cb9b..988ac1487f 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_adopt.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_adopt.js
@@ -5,7 +5,7 @@
  * during the initial browser startup - but it would be hard to do with a mochitest. */
 
 registerCleanupFunction(() => {
-  SidebarUI.hide();
+  SidebarController.hide();
 });
 
 function failIfSidebarFocusedFires() {
@@ -26,7 +26,7 @@ add_task(async function testAdoptedTwoWindows() {
   info("Ensure that sidebar state is adopted only from the opener");
 
   let win1 = await BrowserTestUtils.openNewBrowserWindow();
-  await win1.SidebarUI.show("viewBookmarksSidebar");
+  await win1.SidebarController.show("viewBookmarksSidebar");
   await BrowserTestUtils.closeWindow(win1);
 
   let win2 = await BrowserTestUtils.openNewBrowserWindow();
@@ -34,7 +34,7 @@ add_task(async function testAdoptedTwoWindows() {
     !win2.document.getElementById("sidebar-button").hasAttribute("checked"),
     "Sidebar button isn't checked"
   );
-  ok(!win2.SidebarUI.isOpen, "Sidebar is closed");
+  ok(!win2.SidebarController.isOpen, "Sidebar is closed");
   await BrowserTestUtils.closeWindow(win2);
 });
 
@@ -46,7 +46,7 @@ add_task(async function testEventsReceivedInMainWindow() {
   let initialShown = BrowserTestUtils.waitForEvent(window, "SidebarShown");
   let initialFocus = BrowserTestUtils.waitForEvent(window, "SidebarFocused");
 
-  await SidebarUI.show("viewBookmarksSidebar");
+  await SidebarController.show("viewBookmarksSidebar");
   await initialShown;
   await initialFocus;
 
diff --git a/browser/base/content/test/sidebar/browser_sidebar_app_locale_changed.js b/browser/base/content/test/sidebar/browser_sidebar_app_locale_changed.js
index 5b07da9839..1e52895a7d 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_app_locale_changed.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_app_locale_changed.js
@@ -8,7 +8,7 @@
 
 add_task(function cleanup() {
   registerCleanupFunction(() => {
-    SidebarUI.hide();
+    SidebarController.hide();
   });
 });
 
@@ -17,7 +17,7 @@ add_task(function cleanup() {
  */
 async function testLiveReloading(sidebarName) {
   info("Showing the sidebar " + sidebarName);
-  await SidebarUI.show(sidebarName);
+  await SidebarController.show(sidebarName);
 
   function getTreeChildren() {
     const sidebarDoc =
@@ -44,7 +44,7 @@ async function testLiveReloading(sidebarName) {
   );
 
   info("Hiding the sidebar");
-  SidebarUI.hide();
+  SidebarController.hide();
 }
 
 add_task(async function test_bookmarks_sidebar() {
diff --git a/browser/base/content/test/sidebar/browser_sidebar_keys.js b/browser/base/content/test/sidebar/browser_sidebar_keys.js
index f12d1cf5f7..61e4ce9737 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_keys.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_keys.js
@@ -11,11 +11,11 @@ async function testSidebarKeyToggle(key, options, expectedSidebarId) {
     expectedSidebarId
   );
   EventUtils.synthesizeKey(key, options);
-  Assert.ok(!SidebarUI.isOpen);
+  Assert.ok(!SidebarController.isOpen);
 }
 
 add_task(async function test_sidebar_keys() {
-  registerCleanupFunction(() => SidebarUI.hide());
+  registerCleanupFunction(() => SidebarController.hide());
 
   await testSidebarKeyToggle("b", { accelKey: true }, "viewBookmarksSidebar");
 
@@ -30,7 +30,7 @@ add_task(async function test_sidebar_in_customize_mode() {
   let { CustomizableUI } = ChromeUtils.importESModule(
     "resource:///modules/CustomizableUI.sys.mjs"
   );
-  registerCleanupFunction(() => SidebarUI.hide());
+  registerCleanupFunction(() => SidebarController.hide());
 
   let placement = CustomizableUI.getPlacementOfWidget("sidebar-button");
   if (!(placement?.area == CustomizableUI.AREA_NAVBAR)) {
@@ -55,7 +55,7 @@ add_task(async function test_sidebar_in_customize_mode() {
     ).a;
 
   let promiseShown = BrowserTestUtils.waitForEvent(window, "SidebarShown");
-  SidebarUI.show("viewBookmarksSidebar");
+  SidebarController.show("viewBookmarksSidebar");
   await promiseShown;
 
   Assert.greater(
@@ -80,8 +80,8 @@ add_task(async function test_sidebar_in_customize_mode() {
   );
 
   // Attempt toggle - should fail in customize mode.
-  await SidebarUI.toggle();
-  ok(SidebarUI.isOpen, "Sidebar is still open");
+  await SidebarController.toggle();
+  ok(SidebarController.isOpen, "Sidebar is still open");
 
   // Exit customize mode. This should re-enable the toggle and make the sidebar
   // toggle widget appear checked again, since toggle() didn't hide the sidebar.
@@ -98,8 +98,8 @@ add_task(async function test_sidebar_in_customize_mode() {
     "Sidebar widget background should appear checked again"
   );
 
-  await SidebarUI.toggle();
-  ok(!SidebarUI.isOpen, "Sidebar is closed");
+  await SidebarController.toggle();
+  ok(!SidebarController.isOpen, "Sidebar is closed");
   Assert.equal(
     getBGAlpha(),
     0,
diff --git a/browser/base/content/test/sidebar/browser_sidebar_move.js b/browser/base/content/test/sidebar/browser_sidebar_move.js
index d434b3bbd8..05ea9e3322 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_move.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_move.js
@@ -1,17 +1,17 @@
 registerCleanupFunction(() => {
   Services.prefs.clearUserPref("sidebar.position_start");
-  SidebarUI.hide();
+  SidebarController.hide();
 });
 
 const EXPECTED_START_ORDINALS = [
-  ["sidebar-launcher", 1],
+  ["sidebar-main", 1],
   ["sidebar-box", 2],
   ["sidebar-splitter", 3],
   ["appcontent", 4],
 ];
 
 const EXPECTED_END_ORDINALS = [
-  ["sidebar-launcher", 5],
+  ["sidebar-main", 5],
   ["sidebar-box", 4],
   ["sidebar-splitter", 3],
   ["appcontent", 2],
@@ -25,8 +25,8 @@ function getBrowserChildrenWithOrdinals() {
 }
 
 add_task(async function () {
-  await SidebarUI.show("viewBookmarksSidebar");
-  SidebarUI.showSwitcherPanel();
+  await SidebarController.show("viewBookmarksSidebar");
+  SidebarController.showSwitcherPanel();
 
   let reversePositionButton = document.getElementById(
     "sidebar-reverse-position"
@@ -43,8 +43,8 @@ add_task(async function () {
   ok(!box.hasAttribute("positionend"), "Positioned start");
 
   // Moved to right
-  SidebarUI.reversePosition();
-  SidebarUI.showSwitcherPanel();
+  SidebarController.reversePosition();
+  SidebarController.showSwitcherPanel();
   Assert.deepEqual(
     getBrowserChildrenWithOrdinals(),
     EXPECTED_END_ORDINALS,
@@ -58,8 +58,8 @@ add_task(async function () {
   ok(box.hasAttribute("positionend"), "Positioned end");
 
   // Moved to back to left
-  SidebarUI.reversePosition();
-  SidebarUI.showSwitcherPanel();
+  SidebarController.reversePosition();
+  SidebarController.showSwitcherPanel();
   Assert.deepEqual(
     getBrowserChildrenWithOrdinals(),
     EXPECTED_START_ORDINALS,
diff --git a/browser/base/content/test/sidebar/browser_sidebar_persist.js b/browser/base/content/test/sidebar/browser_sidebar_persist.js
index fe67bed9e0..4977c7ef0f 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_persist.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_persist.js
@@ -18,7 +18,7 @@ add_task(async function persist_sidebar_width() {
   {
     info("Showing new window and setting sidebar box");
     const win = await BrowserTestUtils.openNewBrowserWindow();
-    await win.SidebarUI.show("viewBookmarksSidebar");
+    await win.SidebarController.show("viewBookmarksSidebar");
     win.document.getElementById("sidebar-box").style.width = "100px";
     await BrowserTestUtils.closeWindow(win);
   }
@@ -26,7 +26,7 @@ add_task(async function persist_sidebar_width() {
   {
     info("Showing new window and seeing persisted width");
     const win = await BrowserTestUtils.openNewBrowserWindow();
-    await win.SidebarUI.show("viewBookmarksSidebar");
+    await win.SidebarController.show("viewBookmarksSidebar");
     is(
       win.document.getElementById("sidebar-box").style.width,
       "100px",
diff --git a/browser/base/content/test/sidebar/browser_sidebar_switcher.js b/browser/base/content/test/sidebar/browser_sidebar_switcher.js
index 032c23b029..0fc9e18e01 100644
--- a/browser/base/content/test/sidebar/browser_sidebar_switcher.js
+++ b/browser/base/content/test/sidebar/browser_sidebar_switcher.js
@@ -1,5 +1,5 @@
 registerCleanupFunction(() => {
-  SidebarUI.hide();
+  SidebarController.hide();
 });
 
 /**
@@ -9,14 +9,14 @@ registerCleanupFunction(() => {
  */
 function showSwitcherPanelPromise() {
   return new Promise(resolve => {
-    SidebarUI._switcherPanel.addEventListener(
+    SidebarController._switcherPanel.addEventListener(
       "popupshown",
       () => {
         resolve();
       },
       { once: true }
     );
-    SidebarUI.showSwitcherPanel();
+    SidebarController.showSwitcherPanel();
   });
 }
 
@@ -25,7 +25,10 @@ function showSwitcherPanelPromise() {
  * @returns Promise which resolves when the popup menu is opened
  */
 async function waitForSwitcherPopupShown() {
-  return BrowserTestUtils.waitForEvent(SidebarUI._switcherPanel, "popupshown");
+  return BrowserTestUtils.waitForEvent(
+    SidebarController._switcherPanel,
+    "popupshown"
+  );
 }
 
 /**
@@ -63,7 +66,7 @@ async function testSidebarMenuKeyToggle(key, sidebarTitle) {
   info(`Testing "${key}" key handling of sidebar menu popup items
   to access ${sidebarTitle} sidebar`);
 
-  Assert.ok(SidebarUI.isOpen, "Sidebar is open");
+  Assert.ok(SidebarController.isOpen, "Sidebar is open");
 
   let sidebarSwitcher = document.querySelector("#sidebar-switcher-target");
   let sidebar = document.getElementById("sidebar");
@@ -89,7 +92,7 @@ async function testSidebarMenuKeyToggle(key, sidebarTitle) {
     "The sidebar switcher target button is focused"
   );
   Assert.equal(
-    SidebarUI._switcherPanel.state,
+    SidebarController._switcherPanel.state,
     "closed",
     "Sidebar menu popup is closed"
   );
@@ -102,7 +105,7 @@ async function testSidebarMenuKeyToggle(key, sidebarTitle) {
   await promisePopupShown;
 
   Assert.equal(
-    SidebarUI._switcherPanel.state,
+    SidebarController._switcherPanel.state,
     "open",
     "Sidebar menu popup is open"
   );
@@ -111,7 +114,7 @@ async function testSidebarMenuKeyToggle(key, sidebarTitle) {
 
   let arrowDown = async (menuitemId, msg) => {
     let menuItemActive = BrowserTestUtils.waitForEvent(
-      SidebarUI._switcherPanel,
+      SidebarController._switcherPanel,
       "DOMMenuItemActive"
     );
     EventUtils.synthesizeKey("KEY_ArrowDown", {});
@@ -149,18 +152,18 @@ async function testSidebarMenuKeyToggle(key, sidebarTitle) {
   info("Testing keyboard navigation when a sidebar menu popup is closed");
 
   Assert.equal(
-    SidebarUI._switcherPanel.state,
+    SidebarController._switcherPanel.state,
     "closed",
     "Sidebar menu popup is closed"
   );
   // Test the sidebar panel is updated
   Assert.equal(
-    SidebarUI._box.getAttribute("sidebarcommand"),
+    SidebarController._box.getAttribute("sidebarcommand"),
     `view${sidebarTitle}Sidebar` /* e.g. "viewHistorySidebar" */,
     `${sidebarTitle} sidebar loaded`
   );
   Assert.equal(
-    SidebarUI.currentID,
+    SidebarController.currentID,
     `view${sidebarTitle}Sidebar` /* e.g. "viewHistorySidebar" */,
     `${sidebarTitle}'s current ID is updated to a target view`
   );
@@ -173,7 +176,7 @@ add_task(async function markup() {
       false,
       "Unexpected sidebar found - a previous test failed to cleanup correctly"
     );
-    SidebarUI.hide();
+    SidebarController.hide();
   }
 
   let sidebarPopup = document.querySelector("#sidebarMenu-popup");
@@ -205,7 +208,7 @@ add_task(async function markup() {
 
   info("Test dynamic changes in the markup of the sidebar switcher control");
 
-  await SidebarUI.show("viewBookmarksSidebar");
+  await SidebarController.show("viewBookmarksSidebar");
   await showSwitcherPanelPromise();
 
   Assert.equal(
@@ -229,25 +232,25 @@ add_task(async function markup() {
     "Sidebar switcher button is collapsed when a sidebar menu is dismissed"
   );
 
-  SidebarUI.hide();
+  SidebarController.hide();
 });
 
 add_task(async function keynav() {
   // If a sidebar is already open, close it.
-  if (SidebarUI.isOpen) {
+  if (SidebarController.isOpen) {
     Assert.ok(
       false,
       "Unexpected sidebar found - a previous test failed to cleanup correctly"
     );
-    SidebarUI.hide();
+    SidebarController.hide();
   }
 
-  await SidebarUI.show("viewBookmarksSidebar");
+  await SidebarController.show("viewBookmarksSidebar");
 
   await testSidebarMenuKeyToggle("KEY_Enter", "History");
   await testSidebarMenuKeyToggle(" ", "Tabs");
 
-  SidebarUI.hide();
+  SidebarController.hide();
 });
 
 add_task(async function mouse() {
@@ -257,11 +260,11 @@ add_task(async function mouse() {
       false,
       "Unexpected sidebar found - a previous test failed to cleanup correctly"
     );
-    SidebarUI.hide();
+    SidebarController.hide();
   }
 
   let sidebar = document.querySelector("#sidebar-box");
-  await SidebarUI.show("viewBookmarksSidebar");
+  await SidebarController.show("viewBookmarksSidebar");
 
   await showSwitcherPanelPromise();
   await pickSwitcherMenuitem("#sidebar-switcher-history");
diff --git a/browser/base/content/test/static/browser_all_files_referenced.js b/browser/base/content/test/static/browser_all_files_referenced.js
index d73c3fe8de..9668288181 100644
--- a/browser/base/content/test/static/browser_all_files_referenced.js
+++ b/browser/base/content/test/static/browser_all_files_referenced.js
@@ -276,12 +276,6 @@ var allowlist = [
   // find the references)
   { file: "chrome://browser/content/screenshots/copied-notification.svg" },
 
-  // Bug 1875361
-  { file: "chrome://global/content/ml/SummarizerModel.sys.mjs" },
-
-  // Bug 1886130
-  { file: "chrome://global/content/ml/ModelHub.sys.mjs" },
-
   // toolkit/xre/MacRunFromDmgUtils.mm
   { file: "resource://gre/localization/en-US/toolkit/global/run-from-dmg.ftl" },
 
@@ -290,6 +284,12 @@ var allowlist = [
   { file: "chrome://browser/content/screenshots/copy.svg" },
   { file: "chrome://browser/content/screenshots/download.svg" },
   { file: "chrome://browser/content/screenshots/download-white.svg" },
+
+  // Referenced programmatically
+  { file: "chrome://browser/content/backup/BackupManifest.1.schema.json" },
+
+  // Bug 1892002
+  { file: "resource://app/modules/TopSites.sys.mjs" },
 ];
 
 if (AppConstants.NIGHTLY_BUILD) {
@@ -301,6 +301,10 @@ if (AppConstants.NIGHTLY_BUILD) {
       // A debug tool that is only available in Nightly builds, and is accessed
       // directly by developers via the chrome URI (bug 1888491)
       { file: "chrome://browser/content/backup/debug.html" },
+
+      // The Transformers.js prod lib is not used in Nightly builds
+      { file: "chrome://global/content/ml/transformers.js" },
+      { file: "chrome://global/content/ml/ort.js" },
     ]
   );
 }
diff --git a/browser/base/content/test/static/browser_parsable_css.js b/browser/base/content/test/static/browser_parsable_css.js
index fb91da578a..6b075fc98f 100644
--- a/browser/base/content/test/static/browser_parsable_css.js
+++ b/browser/base/content/test/static/browser_parsable_css.js
@@ -36,6 +36,12 @@ let ignoreList = [
     errorMessage: /Unknown property.*overflow-clip-box/i,
     isFromDevTools: false,
   },
+  // content: -moz-alt-content is UA-only.
+  {
+    sourceName: /\b(html)\.css$/i,
+    errorMessage: /Error in parsing value for ‘content’/i,
+    isFromDevTools: false,
+  },
   // These variables are declared somewhere else, and error when we load the
   // files directly. They're all marked intermittent because their appearance
   // in the error console seems to not be consistent.
diff --git a/browser/base/content/test/static/browser_parsable_script.js b/browser/base/content/test/static/browser_parsable_script.js
index 3d8fbc1535..71a2930ddc 100644
--- a/browser/base/content/test/static/browser_parsable_script.js
+++ b/browser/base/content/test/static/browser_parsable_script.js
@@ -19,6 +19,7 @@ const kESModuleList = new Set([
   /browser\/vpn-card.js$/,
   /toolkit\/content\/global\/certviewer\/components\/.*\.js$/,
   /toolkit\/content\/global\/certviewer\/.*\.js$/,
+  /toolkit\/content\/global\/ml\/transformers.*\.js$/,
   /chrome\/pdfjs\/content\/web\/.*\.js$/,
 ]);
 
diff --git a/browser/base/content/test/static/browser_sentence_case_strings.js b/browser/base/content/test/static/browser_sentence_case_strings.js
index e995f76b1a..12952c9600 100644
--- a/browser/base/content/test/static/browser_sentence_case_strings.js
+++ b/browser/base/content/test/static/browser_sentence_case_strings.js
@@ -103,7 +103,7 @@ function checkSubheaders(view) {
 }
 
 async function checkUpdateBanner(view) {
-  let banner = view.querySelector("#appMenu-proton-update-banner");
+  let banner = view.querySelector("#appMenu-update-banner");
 
   const notifications = [
     "update-downloading",
diff --git a/browser/base/content/test/sync/browser_contextmenu_sendpage.js b/browser/base/content/test/sync/browser_contextmenu_sendpage.js
index a80cf8a1d0..14b5f72860 100644
--- a/browser/base/content/test/sync/browser_contextmenu_sendpage.js
+++ b/browser/base/content/test/sync/browser_contextmenu_sendpage.js
@@ -93,47 +93,44 @@ add_task(async function test_link_contextmenu() {
     "context-sendlinktodevice-popup"
   );
 
-  let expectedArray = ["context-openlinkintab"];
-
-  if (
+  const expectOpenLinkInUserContextMenu =
     Services.prefs.getBoolPref("privacy.userContext.enabled") &&
-    ContextualIdentityService.getPublicIdentities().length
-  ) {
-    expectedArray.push("context-openlinkinusercontext-menu");
-  }
+    ContextualIdentityService.getPublicIdentities().length;
+
+  const expectStripOnShareLink = Services.prefs.getBoolPref(
+    "privacy.query_stripping.strip_on_share.enabled"
+  );
+
+  const expectTranslateSelection =
+    Services.prefs.getBoolPref("browser.translations.enable") &&
+    Services.prefs.getBoolPref("browser.translations.select.enable");
 
-  expectedArray.push(
+  const expectInspectAccessibility =
+    Services.prefs.getBoolPref("devtools.accessibility.enabled", true) &&
+    (Services.prefs.getBoolPref("devtools.everOpened", false) ||
+      Services.prefs.getIntPref("devtools.selfxss.count", 0) > 0);
+
+  const expectedArray = [
+    "context-openlinkintab",
+    ...(expectOpenLinkInUserContextMenu
+      ? ["context-openlinkinusercontext-menu"]
+      : []),
     "context-openlink",
     "context-openlinkprivate",
     "context-sep-open",
     "context-bookmarklink",
     "context-savelink",
     "context-savelinktopocket",
-    "context-copylink"
-  );
-
-  if (
-    Services.prefs.getBoolPref("privacy.query_stripping.strip_on_share.enabled")
-  ) {
-    expectedArray.push("context-stripOnShareLink");
-  }
-
-  expectedArray.push(
+    "context-copylink",
+    ...(expectStripOnShareLink ? ["context-stripOnShareLink"] : []),
     "context-sendlinktodevice",
     "context-sep-sendlinktodevice",
     "context-searchselect",
-    "frame-sep"
-  );
-
-  if (
-    Services.prefs.getBoolPref("devtools.accessibility.enabled", true) &&
-    (Services.prefs.getBoolPref("devtools.everOpened", false) ||
-      Services.prefs.getIntPref("devtools.selfxss.count", 0) > 0)
-  ) {
-    expectedArray.push("context-inspect-a11y");
-  }
-
-  expectedArray.push("context-inspect");
+    ...(expectTranslateSelection ? ["context-translate-selection"] : []),
+    "frame-sep",
+    ...(expectInspectAccessibility ? ["context-inspect-a11y"] : []),
+    "context-inspect",
+  ];
 
   let menu = document.getElementById("contentAreaContextMenu");
 
diff --git a/browser/base/content/test/sync/browser_sync.js b/browser/base/content/test/sync/browser_sync.js
index 8f687842a4..03077ea67c 100644
--- a/browser/base/content/test/sync/browser_sync.js
+++ b/browser/base/content/test/sync/browser_sync.js
@@ -607,17 +607,20 @@ add_task(async function test_experiment_ui_state_unconfigured() {
   checkFxAAvatar("not_configured");
 
   let expectedLabel = gSync.fluentStrings.formatValueSync(
-    "appmenuitem-sign-in-account"
+    "synced-tabs-fxa-sign-in"
+  );
+
+  let expectedDescriptionLabel = gSync.fluentStrings.formatValueSync(
+    "fxa-menu-sync-description"
   );
 
   await openMainPanel();
 
   checkFxaToolbarButtonPanel({
     headerTitle: expectedLabel,
-    headerDescription: "",
+    headerDescription: expectedDescriptionLabel,
     enabledItems: [
       "PanelUI-fxa-cta-menu",
-      "PanelUI-fxa-menu-sync-button",
       "PanelUI-fxa-menu-monitor-button",
       "PanelUI-fxa-menu-relay-button",
       "PanelUI-fxa-menu-vpn-button",
@@ -690,7 +693,6 @@ add_task(async function test_experiment_ui_state_signedin() {
       "PanelUI-fxa-menu-sync-prefs-button",
       "PanelUI-fxa-menu-account-signout-button",
       "PanelUI-fxa-cta-menu",
-      "PanelUI-fxa-menu-sync-button",
       "PanelUI-fxa-menu-monitor-button",
       "PanelUI-fxa-menu-relay-button",
       "PanelUI-fxa-menu-vpn-button",
diff --git a/browser/base/content/test/tabPrompts/browser.toml b/browser/base/content/test/tabPrompts/browser.toml
index 037f1f0d2b..aa7d4c724e 100644
--- a/browser/base/content/test/tabPrompts/browser.toml
+++ b/browser/base/content/test/tabPrompts/browser.toml
@@ -39,6 +39,8 @@ support-files = ["file_beforeunload_stop.html"]
 https_first_disabled = true
 support-files = ["openPromptOffTimeout.html"]
 
+["browser_promptDelays.js"]
+
 ["browser_promptFocus.js"]
 
 ["browser_prompt_close_event.js"]
diff --git a/browser/base/content/test/tabPrompts/browser_promptDelays.js b/browser/base/content/test/tabPrompts/browser_promptDelays.js
new file mode 100644
index 0000000000..ecd01cdb69
--- /dev/null
+++ b/browser/base/content/test/tabPrompts/browser_promptDelays.js
@@ -0,0 +1,113 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const PERMISSION_DIALOG =
+  "chrome://mozapps/content/handling/permissionDialog.xhtml";
+
+add_setup(async function () {
+  // Set a new handler as default.
+  const protoSvc = Cc[
+    "@mozilla.org/uriloader/external-protocol-service;1"
+  ].getService(Ci.nsIExternalProtocolService);
+  let protoInfo = protoSvc.getProtocolHandlerInfo("web+testprotocol");
+  protoInfo.preferredAction = protoInfo.useHelperApp;
+  let handler = Cc["@mozilla.org/uriloader/web-handler-app;1"].createInstance(
+    Ci.nsIWebHandlerApp
+  );
+  handler.uriTemplate = "https://example.com/foobar?uri=%s";
+  handler.name = "Test protocol";
+  let handlers = protoInfo.possibleApplicationHandlers;
+  handlers.appendElement(handler);
+
+  protoInfo.preferredApplicationHandler = handler;
+  protoInfo.alwaysAskBeforeHandling = false;
+
+  const handlerSvc = Cc["@mozilla.org/uriloader/handler-service;1"].getService(
+    Ci.nsIHandlerService
+  );
+  handlerSvc.store(protoInfo);
+
+  registerCleanupFunction(() => {
+    handlerSvc.remove(protoInfo);
+  });
+});
+
+add_task(async function test_promptWhileNotForeground() {
+  await BrowserTestUtils.withNewTab("about:blank", async browser => {
+    let windowOpened = BrowserTestUtils.waitForNewWindow();
+    await SpecialPowers.spawn(browser, [], () => {
+      content.eval(`window.open('about:blank', "_blank", "height=600");`);
+    });
+    let otherWin = await windowOpened;
+    info("Opened extra window, now start a prompt.");
+
+    // To ensure we test the delay helper correctly, shorten the delay:
+    await SpecialPowers.pushPrefEnv({
+      set: [["security.dialog_enable_delay", 50]],
+    });
+
+    let promptPromise = BrowserTestUtils.promiseAlertDialogOpen(
+      null,
+      PERMISSION_DIALOG,
+      { isSubDialog: true }
+    );
+    await SpecialPowers.spawn(browser, [], () => {
+      content.document.location.href = "web+testprotocol:hello";
+    });
+    info("Started opening prompt.");
+    let prompt = await promptPromise;
+    info("Opened prompt.");
+    let dialog = prompt.document.querySelector("dialog");
+    let button = dialog.getButton("accept");
+    is(button.getAttribute("disabled"), "true", "Button should be disabled");
+
+    // eslint-disable-next-line mozilla/no-arbitrary-setTimeout
+    await new Promise(r => setTimeout(r, 500));
+    is(
+      button.getAttribute("disabled"),
+      "true",
+      "Button should still be disabled while the dialog is in the background"
+    );
+
+    let buttonGetsEnabled = BrowserTestUtils.waitForMutationCondition(
+      button,
+      { attributeFilter: ["disabled"] },
+      () => button.getAttribute("disabled") != "true"
+    );
+    await BrowserTestUtils.closeWindow(otherWin);
+    info("Waiting for button to be enabled.");
+    await buttonGetsEnabled;
+    ok(true, "The button was enabled.");
+    dialog.cancelDialog();
+
+    await SpecialPowers.popPrefEnv();
+  });
+});
+
+add_task(async function test_promptWhileForeground() {
+  await BrowserTestUtils.withNewTab("about:blank", async browser => {
+    let promptPromise = BrowserTestUtils.promiseAlertDialogOpen(
+      null,
+      PERMISSION_DIALOG,
+      { isSubDialog: true }
+    );
+    await SpecialPowers.spawn(browser, [], () => {
+      content.document.location.href = "web+testprotocol:hello";
+    });
+    info("Started opening prompt.");
+    let prompt = await promptPromise;
+    info("Opened prompt.");
+    let dialog = prompt.document.querySelector("dialog");
+    let button = dialog.getButton("accept");
+    is(button.getAttribute("disabled"), "true", "Button should be disabled");
+    await BrowserTestUtils.waitForMutationCondition(
+      button,
+      { attributeFilter: ["disabled"] },
+      () => button.getAttribute("disabled") != "true"
+    );
+    ok(true, "The button was enabled.");
+    dialog.cancelDialog();
+  });
+});
diff --git a/browser/base/content/test/tabPrompts/browser_promptFocus.js b/browser/base/content/test/tabPrompts/browser_promptFocus.js
index 89ca064c10..cab812f57b 100644
--- a/browser/base/content/test/tabPrompts/browser_promptFocus.js
+++ b/browser/base/content/test/tabPrompts/browser_promptFocus.js
@@ -20,8 +20,7 @@ add_task(async function test_tabdialogbox_tab_switch_focus() {
     tabPromises.push(
       BrowserTestUtils.openNewForegroundTab(
         gBrowser,
-        // eslint-disable-next-line @microsoft/sdl/no-insecure-url
-        "http://example.com",
+        "https://example.com",
         true
       )
     );
diff --git a/browser/base/content/test/tabs/browser.toml b/browser/base/content/test/tabs/browser.toml
index fa77a8b1a4..8a95c87a6e 100644
--- a/browser/base/content/test/tabs/browser.toml
+++ b/browser/base/content/test/tabs/browser.toml
@@ -30,6 +30,8 @@ skip-if = [
 ["browser_bfcache_exemption_about_pages.js"]
 skip-if = ["!fission"]
 
+["browser_blank_tab_label.js"]
+
 ["browser_bug580956.js"]
 
 ["browser_bug_1387976_restore_lazy_tab_browser_muted_state.js"]
@@ -140,6 +142,8 @@ support-files = [
 
 ["browser_multiselect_tabs_close.js"]
 
+["browser_multiselect_tabs_close_duplicate_tabs.js"]
+
 ["browser_multiselect_tabs_close_other_tabs.js"]
 
 ["browser_multiselect_tabs_close_tabs_to_the_left.js"]
diff --git a/browser/base/content/test/tabs/browser_blank_tab_label.js b/browser/base/content/test/tabs/browser_blank_tab_label.js
new file mode 100644
index 0000000000..9fe5f6b1b0
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_blank_tab_label.js
@@ -0,0 +1,49 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+/**
+ * Ensure that we don't use an entirely-blank (non-printable) document title
+ * as the tab label.
+ */
+add_task(async function test_ensure_printable_label() {
+  const TEST_DOC = `
+  <!DOCTYPE html>
+  <meta charset="utf-8">
+  <!-- Title is NO-BREAK SPACE, COMBINING ACUTE ACCENT, ARABIC LETTER MARK -->
+  <title>&nbsp;&%23x0301;&%23x061C;</title>
+  Is my title blank?`;
+
+  let newTab;
+  function tabLabelChecker() {
+    Assert.stringMatches(
+      newTab.label,
+      /\p{L}|\p{N}|\p{P}|\p{S}/u,
+      "Tab label should contain printable character."
+    );
+  }
+  let mutationObserver = new MutationObserver(tabLabelChecker);
+  registerCleanupFunction(() => mutationObserver.disconnect());
+
+  gBrowser.tabContainer.addEventListener(
+    "TabOpen",
+    event => {
+      newTab = event.target;
+      tabLabelChecker();
+      mutationObserver.observe(newTab, {
+        attributeFilter: ["label"],
+      });
+    },
+    { once: true }
+  );
+
+  await BrowserTestUtils.withNewTab("data:text/html," + TEST_DOC, async () => {
+    // Wait another longer-than-tick to ensure more mutation observer things have
+    // come in.
+    await new Promise(executeSoon);
+
+    // Check one last time for good measure, for the final label:
+    tabLabelChecker();
+  });
+});
diff --git a/browser/base/content/test/tabs/browser_multiselect_tabs_close_duplicate_tabs.js b/browser/base/content/test/tabs/browser_multiselect_tabs_close_duplicate_tabs.js
new file mode 100644
index 0000000000..d18795447f
--- /dev/null
+++ b/browser/base/content/test/tabs/browser_multiselect_tabs_close_duplicate_tabs.js
@@ -0,0 +1,178 @@
+const PREF_WARN_ON_CLOSE = "browser.tabs.warnOnCloseOtherTabs";
+const PREF_SHOWN_DUPE_DIALOG =
+  "browser.tabs.haveShownCloseAllDuplicateTabsWarning";
+
+add_task(async function setPref() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      [PREF_WARN_ON_CLOSE, false],
+      [PREF_SHOWN_DUPE_DIALOG, true],
+    ],
+  });
+});
+
+add_task(async function withAMultiSelectedTab() {
+  let initialTab = gBrowser.selectedTab;
+  let tab1 = await addTab();
+  let tab2 = await addTab();
+  let tab3 = await addTab();
+  let tab4 = await addTab();
+
+  is(gBrowser.multiSelectedTabsCount, 0, "Zero multiselected tabs");
+
+  await triggerClickOn(tab1, { ctrlKey: true });
+
+  let tab4Pinned = BrowserTestUtils.waitForEvent(tab4, "TabPinned");
+  gBrowser.pinTab(tab4);
+  await tab4Pinned;
+
+  ok(initialTab.multiselected, "InitialTab is multiselected");
+  ok(tab1.multiselected, "Tab1 is multiselected");
+  ok(!tab2.multiselected, "Tab2 is not multiselected");
+  ok(!tab3.multiselected, "Tab3 is not multiselected");
+  ok(!tab4.multiselected, "Tab4 is not multiselected");
+  ok(tab4.pinned, "Tab4 is pinned");
+  is(gBrowser.multiSelectedTabsCount, 2, "Two multiselected tabs");
+  is(gBrowser.selectedTab, initialTab, "InitialTab is the active tab");
+
+  let closingTabs = [tab2, tab3];
+  let tabClosingPromises = [];
+  for (let tab of closingTabs) {
+    tabClosingPromises.push(BrowserTestUtils.waitForTabClosing(tab));
+  }
+
+  gBrowser.removeDuplicateTabs(tab1);
+
+  await Promise.all(tabClosingPromises);
+
+  ok(!initialTab.closing, "InitialTab is not closing");
+  ok(!tab1.closing, "Tab1 is not closing");
+  ok(tab2.closing, "Tab2 is closing");
+  ok(tab3.closing, "Tab3 is closing");
+  ok(!tab4.closing, "Tab4 is not closing");
+  is(gBrowser.multiSelectedTabsCount, 2, "Two multiselected tabs");
+  is(gBrowser.selectedTab, initialTab, "InitialTab is still the active tab");
+
+  gBrowser.clearMultiSelectedTabs();
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab4);
+});
+
+add_task(async function withNotAMultiSelectedTab() {
+  let initialTab = gBrowser.selectedTab;
+  let tab1 = await addTab("http://mochi.test:8888/");
+  let tab2 = await addTab("http://mochi.test:8888/");
+  let tab3 = await addTab("http://mochi.test:8888/");
+  let tab4 = await addTab("http://mochi.test:8888/");
+  let tab5 = await addTab("http://mochi.test:8888/");
+  let tab6 = await addTab("http://mochi.test:8888/", { userContextId: 1 });
+
+  is(gBrowser.multiSelectedTabsCount, 0, "Zero multiselected tabs");
+
+  await BrowserTestUtils.switchTab(gBrowser, tab1);
+  await triggerClickOn(tab2, { ctrlKey: true });
+  await triggerClickOn(tab5, { ctrlKey: true });
+
+  let tab4Pinned = BrowserTestUtils.waitForEvent(tab4, "TabPinned");
+  gBrowser.pinTab(tab4);
+  await tab4Pinned;
+
+  let tab5Pinned = BrowserTestUtils.waitForEvent(tab5, "TabPinned");
+  gBrowser.pinTab(tab5);
+  await tab5Pinned;
+
+  ok(!initialTab.multiselected, "InitialTab is not multiselected");
+  ok(tab1.multiselected, "Tab1 is multiselected");
+  ok(tab2.multiselected, "Tab2 is multiselected");
+  ok(!tab3.multiselected, "Tab3 is not multiselected");
+  ok(!tab4.multiselected, "Tab4 is not multiselected");
+  ok(tab4.pinned, "Tab4 is pinned");
+  ok(tab5.multiselected, "Tab5 is multiselected");
+  ok(tab5.pinned, "Tab5 is pinned");
+  ok(!tab6.multiselected, "Tab6 is not multiselected");
+  ok(!tab6.pinned, "Tab6 is not pinned");
+  is(gBrowser.multiSelectedTabsCount, 3, "Three multiselected tabs");
+  is(gBrowser.selectedTab, tab1, "Tab1 is the active tab");
+
+  let closingTabs = [tab1, tab2];
+  let tabClosingPromises = [];
+  for (let tab of closingTabs) {
+    tabClosingPromises.push(BrowserTestUtils.waitForTabClosing(tab));
+  }
+
+  await BrowserTestUtils.switchTab(
+    gBrowser,
+    gBrowser.removeDuplicateTabs(tab3)
+  );
+
+  await Promise.all(tabClosingPromises);
+
+  ok(!initialTab.closing, "InitialTab is not closing");
+  ok(tab1.closing, "Tab1 is closing");
+  ok(tab2.closing, "Tab2 is closing");
+  ok(!tab3.closing, "Tab3 is not closing");
+  ok(!tab4.closing, "Tab4 is not closing");
+  ok(!tab5.closing, "Tab5 is not closing");
+  ok(!tab6.closing, "Tab6 is not closing");
+  is(
+    gBrowser.multiSelectedTabsCount,
+    0,
+    "Zero multiselected tabs, selection is cleared"
+  );
+  is(gBrowser.selectedTab, tab3, "tab3 is the active tab now");
+
+  for (let tab of [tab3, tab4, tab5, tab6]) {
+    BrowserTestUtils.removeTab(tab);
+  }
+});
+
+add_task(async function closeAllDuplicateTabs() {
+  let initialTab = gBrowser.selectedTab;
+  let tab1 = await addTab("http://mochi.test:8888/one");
+  let tab2 = await addTab("http://mochi.test:8888/two", { userContextId: 1 });
+  let tab3 = await addTab("http://mochi.test:8888/one");
+  let tab4 = await addTab("http://mochi.test:8888/two");
+  let tab5 = await addTab("http://mochi.test:8888/one");
+  let tab6 = await addTab("http://mochi.test:8888/two");
+
+  let tab1Pinned = BrowserTestUtils.waitForEvent(tab1, "TabPinned");
+  gBrowser.pinTab(tab1);
+  await tab1Pinned;
+
+  // So we have 1p,2c,1,2,1,2
+  // We expect 1p,2c,X,2,X,X because the pinned 1 will dupe the other two 1,
+  // but the 2c's userContextId makes it unique against the other two 2,
+  // but one of the other two 2 will close.
+
+  // Ensure tab4 remains by making it active more recently than tab6.
+  tab4._lastSeenActive = Date.now(); // as recent as it gets.
+
+  // Assert some preconditions:
+  ok(tab1.pinned, "Tab1 is pinned");
+  Assert.greater(tab4.lastSeenActive, tab6.lastSeenActive);
+
+  let closingTabs = [tab3, tab5, tab6];
+  let tabClosingPromises = [];
+  for (let tab of closingTabs) {
+    tabClosingPromises.push(BrowserTestUtils.waitForTabClosing(tab));
+  }
+
+  await BrowserTestUtils.switchTab(
+    gBrowser,
+    gBrowser.removeAllDuplicateTabs(initialTab)
+  );
+
+  await Promise.all(tabClosingPromises);
+
+  ok(!initialTab.closing, "InitialTab is not closing");
+  ok(!tab1.closing, "Tab1 is not closing");
+  ok(!tab2.closing, "Tab2 is not closing");
+  ok(tab3.closing, "Tab3 is closing");
+  ok(!tab4.closing, "Tab4 is not closing");
+  ok(tab5.closing, "Tab5 is closing");
+  ok(tab6.closing, "Tab6 is closing");
+
+  for (let tab of [tab1, tab2, tab4]) {
+    BrowserTestUtils.removeTab(tab);
+  }
+});
diff --git a/browser/base/content/test/tabs/browser_tab_preview.js b/browser/base/content/test/tabs/browser_tab_preview.js
index 0f83b1e28c..19ba85b9f8 100644
--- a/browser/base/content/test/tabs/browser_tab_preview.js
+++ b/browser/base/content/test/tabs/browser_tab_preview.js
@@ -34,6 +34,7 @@ add_setup(async function () {
     set: [
       ["browser.tabs.cardPreview.enabled", true],
       ["browser.tabs.cardPreview.showThumbnails", false],
+      ["browser.tabs.tooltipsShowPidAndActiveness", false],
       ["ui.tooltip.delay_ms", 0],
     ],
   });
@@ -82,6 +83,99 @@ add_task(async function hoverTests() {
 });
 
 /**
+ * Verify that the pid and activeness statuses are not shown
+ * when the flag is not enabled.
+ */
+add_task(async function pidAndActivenessHiddenByDefaultTests() {
+  const tabUrl1 =
+    "data:text/html,<html><head><title>First New Tab</title></head><body>Hello</body></html>";
+  const tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, tabUrl1);
+  const previewContainer = document.getElementById("tab-preview-panel");
+
+  await openPreview(tab1);
+  Assert.equal(
+    previewContainer.querySelector(".tab-preview-pid").innerText,
+    "",
+    "Tab PID is not shown"
+  );
+  Assert.equal(
+    previewContainer.querySelector(".tab-preview-activeness").innerText,
+    "",
+    "Tab activeness is not shown"
+  );
+
+  await closePreviews();
+
+  BrowserTestUtils.removeTab(tab1);
+
+  // Move the mouse outside of the tab strip.
+  EventUtils.synthesizeMouseAtCenter(document.documentElement, {
+    type: "mouseover",
+  });
+});
+
+add_task(async function pidAndActivenessTests() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.tabs.tooltipsShowPidAndActiveness", true]],
+  });
+
+  const tabUrl1 =
+    "data:text/html,<html><head><title>Single process tab</title></head><body>Hello</body></html>";
+  const tab1 = await BrowserTestUtils.openNewForegroundTab(gBrowser, tabUrl1);
+  const tabUrl2 = `data:text/html,<html>
+      <head>
+        <title>Multi-process tab</title>
+      </head>
+      <body>
+        <iframe
+          id="inlineFrameExample"
+          title="Inline Frame Example"
+          width="300"
+          height="200"
+          src="https://example.com">
+        </iframe>
+      </body>
+    </html>`;
+  const tab2 = await BrowserTestUtils.openNewForegroundTab(gBrowser, tabUrl2);
+  const previewContainer = document.getElementById("tab-preview-panel");
+
+  await openPreview(tab1);
+  Assert.stringMatches(
+    previewContainer.querySelector(".tab-preview-pid").innerText,
+    /^pid: \d+$/,
+    "Tab PID is shown on single process tab"
+  );
+  Assert.equal(
+    previewContainer.querySelector(".tab-preview-activeness").innerText,
+    "",
+    "Tab activeness is not shown on inactive tab"
+  );
+  await closePreviews();
+
+  await openPreview(tab2);
+  Assert.stringMatches(
+    previewContainer.querySelector(".tab-preview-pid").innerText,
+    /^pids: \d+, \d+$/,
+    "Tab PIDs are shown on multi-process tab"
+  );
+  Assert.equal(
+    previewContainer.querySelector(".tab-preview-activeness").innerText,
+    "[A]",
+    "Tab activeness is shown on active tab"
+  );
+  await closePreviews();
+
+  BrowserTestUtils.removeTab(tab1);
+  BrowserTestUtils.removeTab(tab2);
+  await SpecialPowers.popPrefEnv();
+
+  // Move the mouse outside of the tab strip.
+  EventUtils.synthesizeMouseAtCenter(document.documentElement, {
+    type: "mouseover",
+  });
+});
+
+/**
  * Verify that non-selected tabs display a thumbnail in their preview
  * when browser.tabs.cardPreview.showThumbnails is set to true,
  * while the currently selected tab never displays a thumbnail in its preview.
diff --git a/browser/base/content/test/tabs/browser_visibleTabs_contextMenu.js b/browser/base/content/test/tabs/browser_visibleTabs_contextMenu.js
index 202c43ce47..06fdd27d9c 100644
--- a/browser/base/content/test/tabs/browser_visibleTabs_contextMenu.js
+++ b/browser/base/content/test/tabs/browser_visibleTabs_contextMenu.js
@@ -2,11 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-const remoteClientsFixture = [
-  { id: 1, name: "Foo" },
-  { id: 2, name: "Bar" },
-];
-
 add_task(async function test() {
   // There should be one tab when we start the test
   let [origTab] = gBrowser.visibleTabs;
@@ -16,9 +11,8 @@ add_task(async function test() {
 
   // Check the context menu with two tabs
   updateTabContextMenu(origTab);
-  is(
-    document.getElementById("context_closeTab").disabled,
-    false,
+  ok(
+    !document.getElementById("context_closeTab").disabled,
     "Close Tab is enabled"
   );
 
@@ -29,11 +23,14 @@ add_task(async function test() {
 
   // Check the context menu with one tab.
   updateTabContextMenu(testTab);
-  is(
-    document.getElementById("context_closeTab").disabled,
-    false,
+  ok(
+    !document.getElementById("context_closeTab").disabled,
     "Close Tab is enabled when more than one tab exists"
   );
+  ok(
+    !document.getElementById("context_closeDuplicateTabs").disabled,
+    "Close duplicate tabs is enabled when more than one tab with the same URL exists"
+  );
 
   // Add a tab that will get pinned
   // So now there's one pinned tab, one visible unpinned tab, and one hidden tab
diff --git a/browser/base/content/test/webextensions/browser_aboutaddons_blanktab.js b/browser/base/content/test/webextensions/browser_aboutaddons_blanktab.js
index 228fe71815..1e0814ea96 100644
--- a/browser/base/content/test/webextensions/browser_aboutaddons_blanktab.js
+++ b/browser/base/content/test/webextensions/browser_aboutaddons_blanktab.js
@@ -8,7 +8,7 @@ add_task(async function testBlankTabReusedAboutAddons() {
     is(browser, gBrowser.selectedBrowser, "New tab is selected");
 
     // Opening about:addons shouldn't change the selected tab.
-    BrowserOpenAddonsMgr();
+    BrowserAddonUI.openAddonsMgr();
 
     is(browser, gBrowser.selectedBrowser, "No new tab was opened");
 
diff --git a/browser/base/content/test/webextensions/browser_extension_sideloading.js b/browser/base/content/test/webextensions/browser_extension_sideloading.js
index 4e1fe07194..5d8f82a178 100644
--- a/browser/base/content/test/webextensions/browser_extension_sideloading.js
+++ b/browser/base/content/test/webextensions/browser_extension_sideloading.js
@@ -16,11 +16,14 @@ const kSideloaded = true;
 async function createWebExtension(details) {
   let options = {
     manifest: {
+      manifest_version: details.manifest_version ?? 2,
+
       browser_specific_settings: { gecko: { id: details.id } },
 
       name: details.name,
 
       permissions: details.permissions,
+      host_permissions: details.host_permissions,
     },
   };
 
@@ -86,9 +89,10 @@ add_task(async function test_sideloading() {
 
   const ID2 = "addon2@tests.mozilla.org";
   await createWebExtension({
+    manifest_version: 3,
     id: ID2,
     name: "Test 2",
-    permissions: ["<all_urls>"],
+    host_permissions: ["<all_urls>"],
   });
 
   const ID3 = "addon3@tests.mozilla.org";
@@ -224,7 +228,7 @@ add_task(async function test_sideloading() {
   // Close the hamburger menu and go directly to the addons manager
   await gCUITestUtils.hideMainMenu();
 
-  win = await BrowserOpenAddonsMgr(VIEW);
+  win = await BrowserAddonUI.openAddonsMgr(VIEW);
   await waitAboutAddonsViewLoaded(win.document);
 
   // about:addons addon entry element.
@@ -293,7 +297,7 @@ add_task(async function test_sideloading() {
   // Close the hamburger menu and go to the detail page for this addon
   await gCUITestUtils.hideMainMenu();
 
-  win = await BrowserOpenAddonsMgr(
+  win = await BrowserAddonUI.openAddonsMgr(
     `addons://detail/${encodeURIComponent(ID3)}`
   );
 
diff --git a/browser/base/content/test/webextensions/browser_permissions_local_file.js b/browser/base/content/test/webextensions/browser_permissions_local_file.js
index 22dff8cb38..731e8adea7 100644
--- a/browser/base/content/test/webextensions/browser_permissions_local_file.js
+++ b/browser/base/content/test/webextensions/browser_permissions_local_file.js
@@ -14,7 +14,9 @@ async function installFile(filename) {
   MockFilePicker.setFiles([file]);
   MockFilePicker.afterOpenCallback = MockFilePicker.cleanup;
 
-  let { document } = await BrowserOpenAddonsMgr("addons://list/extension");
+  let { document } = await BrowserAddonUI.openAddonsMgr(
+    "addons://list/extension"
+  );
 
   // Do the install...
   await waitAboutAddonsViewLoaded(document);
diff --git a/browser/base/content/test/webextensions/browser_update_interactive_noprompt.js b/browser/base/content/test/webextensions/browser_update_interactive_noprompt.js
index 0b0b912503..9ad3deaae1 100644
--- a/browser/base/content/test/webextensions/browser_update_interactive_noprompt.js
+++ b/browser/base/content/test/webextensions/browser_update_interactive_noprompt.js
@@ -36,7 +36,7 @@ async function testUpdateNoPrompt(
   is(addon.version, initialVersion, "Version 1 of the addon is installed");
 
   // Go to Extensions in about:addons
-  let win = await BrowserOpenAddonsMgr("addons://list/extension");
+  let win = await BrowserAddonUI.openAddonsMgr("addons://list/extension");
 
   await waitAboutAddonsViewLoaded(win.document);
 
diff --git a/browser/base/content/test/webextensions/head.js b/browser/base/content/test/webextensions/head.js
index f1183c61b8..f364dbed88 100644
--- a/browser/base/content/test/webextensions/head.js
+++ b/browser/base/content/test/webextensions/head.js
@@ -508,7 +508,7 @@ async function interactiveUpdateTest(autoUpdate, checkFn) {
   ok(addon, "Addon was installed");
   is(addon.version, "1.0", "Version 1 of the addon is installed");
 
-  let win = await BrowserOpenAddonsMgr("addons://list/extension");
+  let win = await BrowserAddonUI.openAddonsMgr("addons://list/extension");
 
   await waitAboutAddonsViewLoaded(win.document);