Merging upstream version 125.0.1.

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

84 files changed, 656 insertions, 278 deletions

diff --git a/browser/components/extensions/ExtensionBrowsingData.sys.mjs b/browser/components/extensions/ExtensionBrowsingData.sys.mjs
index 24c6d86050..9ca3be643d 100644
--- a/browser/components/extensions/ExtensionBrowsingData.sys.mjs
+++ b/browser/components/extensions/ExtensionBrowsingData.sys.mjs
@@ -18,7 +18,7 @@ ChromeUtils.defineESModuleGetters(lazy, {
 
 export class BrowsingDataDelegate {
   // Unused for now
-  constructor(extension) {}
+  constructor() {}
 
   // This method returns undefined for all data types that are _not_ handled by
   // this delegate.
diff --git a/browser/components/extensions/ExtensionControlledPopup.sys.mjs b/browser/components/extensions/ExtensionControlledPopup.sys.mjs
index 270dd65827..b07a8214f3 100644
--- a/browser/components/extensions/ExtensionControlledPopup.sys.mjs
+++ b/browser/components/extensions/ExtensionControlledPopup.sys.mjs
@@ -155,7 +155,7 @@ export class ExtensionControlledPopup {
     );
   }
 
-  observe(subject, topic, data) {
+  observe(subject) {
     // Remove the observer here so we don't get multiple open() calls if we get
     // multiple observer events in quick succession.
     this.removeObserver();
diff --git a/browser/components/extensions/ExtensionPopups.sys.mjs b/browser/components/extensions/ExtensionPopups.sys.mjs
index 7549f3202c..dbd34697c7 100644
--- a/browser/components/extensions/ExtensionPopups.sys.mjs
+++ b/browser/components/extensions/ExtensionPopups.sys.mjs
@@ -28,7 +28,7 @@ function promisePopupShown(popup) {
     } else {
       popup.addEventListener(
         "popupshown",
-        function (event) {
+        function () {
           resolve();
         },
         { once: true }
@@ -385,7 +385,7 @@ export class BasePopup {
   }
 
   unblockParser() {
-    this.browserReady.then(browser => {
+    this.browserReady.then(() => {
       if (this.destroyed) {
         return;
       }
diff --git a/browser/components/extensions/child/ext-devtools.js b/browser/components/extensions/child/ext-devtools.js
index 219df7cb07..926c5e47c5 100644
--- a/browser/components/extensions/child/ext-devtools.js
+++ b/browser/components/extensions/child/ext-devtools.js
@@ -7,7 +7,7 @@
 "use strict";
 
 this.devtools = class extends ExtensionAPI {
-  getAPI(context) {
+  getAPI() {
     return {
       devtools: {},
     };
diff --git a/browser/components/extensions/child/ext-menus.js b/browser/components/extensions/child/ext-menus.js
index 6c3b7ae492..2ffbf57132 100644
--- a/browser/components/extensions/child/ext-menus.js
+++ b/browser/components/extensions/child/ext-menus.js
@@ -248,7 +248,7 @@ this.menusInternal = class extends ExtensionAPI {
           }
           pendingMenuEvent = {
             webExtContextData,
-            observe(subject, topic, data) {
+            observe(subject) {
               pendingMenuEvent = null;
               Services.obs.removeObserver(this, "on-prepare-contextmenu");
               subject = subject.wrappedJSObject;
diff --git a/browser/components/extensions/parent/ext-browser.js b/browser/components/extensions/parent/ext-browser.js
index 355f4f0668..7b01d15101 100644
--- a/browser/components/extensions/parent/ext-browser.js
+++ b/browser/components/extensions/parent/ext-browser.js
@@ -108,7 +108,7 @@ global.clickModifiersFromEvent = event => {
 global.waitForTabLoaded = (tab, url) => {
   return new Promise(resolve => {
     windowTracker.addListener("progress", {
-      onLocationChange(browser, webProgress, request, locationURI, flags) {
+      onLocationChange(browser, webProgress, request, locationURI) {
         if (
           webProgress.isTopLevel &&
           browser.ownerGlobal.gBrowser.getTabForBrowser(browser) == tab &&
diff --git a/browser/components/extensions/parent/ext-browserAction.js b/browser/components/extensions/parent/ext-browserAction.js
index 4122856104..521a1195bb 100644
--- a/browser/components/extensions/parent/ext-browserAction.js
+++ b/browser/components/extensions/parent/ext-browserAction.js
@@ -95,7 +95,7 @@ this.browserAction = class extends ExtensionAPIPersistent {
     return browserActionMap.get(extension);
   }
 
-  async onManifestEntry(entryName) {
+  async onManifestEntry() {
     let { extension } = this;
 
     let options =
@@ -341,7 +341,7 @@ this.browserAction = class extends ExtensionAPIPersistent {
         );
       },
 
-      onBeforeCommand: (event, node) => {
+      onBeforeCommand: event => {
         this.lastClickInfo = {
           button: event.button || 0,
           modifiers: clickModifiersFromEvent(event),
diff --git a/browser/components/extensions/parent/ext-chrome-settings-overrides.js b/browser/components/extensions/parent/ext-chrome-settings-overrides.js
index 2e3a285014..1fbb794b51 100644
--- a/browser/components/extensions/parent/ext-chrome-settings-overrides.js
+++ b/browser/components/extensions/parent/ext-chrome-settings-overrides.js
@@ -259,7 +259,7 @@ this.chrome_settings_overrides = class extends ExtensionAPI {
     await chrome_settings_overrides.removeEngine(id);
   }
 
-  async onManifestEntry(entryName) {
+  async onManifestEntry() {
     let { extension } = this;
     let { manifest } = extension;
     let homepageUrl = manifest.chrome_settings_overrides.homepage;
diff --git a/browser/components/extensions/parent/ext-commands.js b/browser/components/extensions/parent/ext-commands.js
index 88e7dae307..328f05a802 100644
--- a/browser/components/extensions/parent/ext-commands.js
+++ b/browser/components/extensions/parent/ext-commands.js
@@ -42,7 +42,7 @@ this.commands = class extends ExtensionAPIPersistent {
     return ExtensionShortcuts.removeCommandsFromStorage(extensionId);
   }
 
-  async onManifestEntry(entryName) {
+  async onManifestEntry() {
     let shortcuts = new ExtensionShortcuts({
       extension: this.extension,
       onCommand: name => this.emit("command", name),
diff --git a/browser/components/extensions/parent/ext-devtools-panels.js b/browser/components/extensions/parent/ext-devtools-panels.js
index 9f0dba5c25..6b83ea5dbb 100644
--- a/browser/components/extensions/parent/ext-devtools-panels.js
+++ b/browser/components/extensions/parent/ext-devtools-panels.js
@@ -593,7 +593,7 @@ this.devtools_panels = class extends ExtensionAPI {
               context,
               name: "devtools.panels.elements.onSelectionChanged",
               register: fire => {
-                const listener = eventName => {
+                const listener = () => {
                   fire.async();
                 };
                 toolboxSelectionObserver.on("selectionChanged", listener);
diff --git a/browser/components/extensions/parent/ext-devtools.js b/browser/components/extensions/parent/ext-devtools.js
index 98efd25489..da6d1fdc2d 100644
--- a/browser/components/extensions/parent/ext-devtools.js
+++ b/browser/components/extensions/parent/ext-devtools.js
@@ -406,7 +406,7 @@ this.devtools = class extends ExtensionAPI {
     this._uninitialize();
   }
 
-  getAPI(context) {
+  getAPI() {
     return {
       devtools: {},
     };
diff --git a/browser/components/extensions/parent/ext-history.js b/browser/components/extensions/parent/ext-history.js
index b7e24aecaa..c47e1090dd 100644
--- a/browser/components/extensions/parent/ext-history.js
+++ b/browser/components/extensions/parent/ext-history.js
@@ -95,7 +95,7 @@ function executeAsyncQuery(historyQuery, options, resultConverter) {
           )
         );
       },
-      handleCompletion(reason) {
+      handleCompletion() {
         resolve(results);
       },
     });
diff --git a/browser/components/extensions/parent/ext-menus.js b/browser/components/extensions/parent/ext-menus.js
index 74ce398b48..a5b27bff7d 100644
--- a/browser/components/extensions/parent/ext-menus.js
+++ b/browser/components/extensions/parent/ext-menus.js
@@ -312,7 +312,7 @@ var gMenuBuilder = {
     return this.customizeElement(element, item, contextData);
   },
 
-  createMenuElement(doc, item) {
+  createMenuElement(doc) {
     let element = doc.createXULElement("menu");
     // Menu elements need to have a menupopup child for its menu items.
     let menupopup = doc.createXULElement("menupopup");
@@ -1084,7 +1084,7 @@ const menuTracker = {
     libraryTracker.uninit(this.cleanupLibrary);
   },
 
-  observe(subject, topic, data) {
+  observe(subject) {
     subject = subject.wrappedJSObject;
     gMenuBuilder.build(subject);
   },
diff --git a/browser/components/extensions/parent/ext-omnibox.js b/browser/components/extensions/parent/ext-omnibox.js
index 363db67325..d8d5f64941 100644
--- a/browser/components/extensions/parent/ext-omnibox.js
+++ b/browser/components/extensions/parent/ext-omnibox.js
@@ -15,7 +15,7 @@ this.omnibox = class extends ExtensionAPIPersistent {
   PERSISTENT_EVENTS = {
     onInputStarted({ fire }) {
       let { extension } = this;
-      let listener = eventName => {
+      let listener = () => {
         fire.sync();
       };
       extension.on(ExtensionSearchHandler.MSG_INPUT_STARTED, listener);
@@ -30,7 +30,7 @@ this.omnibox = class extends ExtensionAPIPersistent {
     },
     onInputCancelled({ fire }) {
       let { extension } = this;
-      let listener = eventName => {
+      let listener = () => {
         fire.sync();
       };
       extension.on(ExtensionSearchHandler.MSG_INPUT_CANCELLED, listener);
@@ -90,7 +90,7 @@ this.omnibox = class extends ExtensionAPIPersistent {
     },
   };
 
-  onManifestEntry(entryName) {
+  onManifestEntry() {
     let { extension } = this;
     let { manifest } = extension;
 
diff --git a/browser/components/extensions/parent/ext-pageAction.js b/browser/components/extensions/parent/ext-pageAction.js
index aa45be8256..7dd07bd282 100644
--- a/browser/components/extensions/parent/ext-pageAction.js
+++ b/browser/components/extensions/parent/ext-pageAction.js
@@ -27,7 +27,7 @@ let pageActionMap = new WeakMap();
 
 class PageAction extends PageActionBase {
   constructor(extension, buttonDelegate) {
-    let tabContext = new TabContext(tab => this.getContextData(null));
+    let tabContext = new TabContext(() => this.getContextData(null));
     super(tabContext, extension);
     this.buttonDelegate = buttonDelegate;
   }
@@ -72,7 +72,7 @@ this.pageAction = class extends ExtensionAPIPersistent {
     BrowserUsageTelemetry.recordWidgetChange(makeWidgetId(id), null, "addon");
   }
 
-  async onManifestEntry(entryName) {
+  async onManifestEntry() {
     let { extension } = this;
     let options = extension.manifest.page_action;
 
@@ -120,7 +120,7 @@ this.pageAction = class extends ExtensionAPIPersistent {
           iconURL: this.action.getProperty(null, "icon"),
           pinnedToUrlbar: this.action.getPinned(),
           disabled: !this.action.getProperty(null, "enabled"),
-          onCommand: (event, buttonNode) => {
+          onCommand: event => {
             this.handleClick(event.target.ownerGlobal, {
               button: event.button || 0,
               modifiers: clickModifiersFromEvent(event),
diff --git a/browser/components/extensions/parent/ext-search.js b/browser/components/extensions/parent/ext-search.js
index 4fe7a096f4..cd65335f48 100644
--- a/browser/components/extensions/parent/ext-search.js
+++ b/browser/components/extensions/parent/ext-search.js
@@ -40,7 +40,7 @@ this.search = class extends ExtensionAPI {
           let defaultEngine = await Services.search.getDefault();
           return Promise.all(
             visibleEngines.map(async engine => {
-              let favIconUrl = engine.getIconURL();
+              let favIconUrl = await engine.getIconURL();
               // Convert moz-extension:-URLs to data:-URLs to make sure that
               // extensions can see icons from other extensions, even if they
               // are not web-accessible.
diff --git a/browser/components/extensions/parent/ext-sidebarAction.js b/browser/components/extensions/parent/ext-sidebarAction.js
index 648b34e557..197456abd9 100644
--- a/browser/components/extensions/parent/ext-sidebarAction.js
+++ b/browser/components/extensions/parent/ext-sidebarAction.js
@@ -28,7 +28,7 @@ this.sidebarAction = class extends ExtensionAPI {
     return sidebarActionMap.get(extension);
   }
 
-  onManifestEntry(entryName) {
+  onManifestEntry() {
     let { extension } = this;
 
     extension.once("ready", this.onReady.bind(this));
diff --git a/browser/components/extensions/parent/ext-tabs.js b/browser/components/extensions/parent/ext-tabs.js
index 53d470e6f1..128a42439b 100644
--- a/browser/components/extensions/parent/ext-tabs.js
+++ b/browser/components/extensions/parent/ext-tabs.js
@@ -82,7 +82,7 @@ let tabListener = {
     }
   },
 
-  onLocationChange(browser, webProgress, request, locationURI, flags) {
+  onLocationChange(browser, webProgress) {
     if (webProgress.isTopLevel) {
       let { gBrowser } = browser.ownerGlobal;
       let nativeTab = gBrowser.getTabForBrowser(browser);
@@ -356,7 +356,7 @@ this.tabs = class extends ExtensionAPIPersistent {
         return windowId;
       }
 
-      function matchFilters(tab, changed) {
+      function matchFilters(tab) {
         if (!filterProps) {
           return true;
         }
@@ -663,7 +663,7 @@ this.tabs = class extends ExtensionAPIPersistent {
         onReplaced: new EventManager({
           context,
           name: "tabs.onReplaced",
-          register: fire => {
+          register: () => {
             return () => {};
           },
         }).api(),
@@ -683,7 +683,7 @@ this.tabs = class extends ExtensionAPIPersistent {
         }).api(),
 
         create(createProperties) {
-          return new Promise((resolve, reject) => {
+          return new Promise(resolve => {
             let window =
               createProperties.windowId !== null
                 ? windowTracker.getWindow(createProperties.windowId, context)
@@ -695,7 +695,7 @@ this.tabs = class extends ExtensionAPIPersistent {
             }
             let { gBrowserInit } = window;
             if (!gBrowserInit || !gBrowserInit.delayedStartupFinished) {
-              let obs = (finishedWindow, topic, data) => {
+              let obs = finishedWindow => {
                 if (finishedWindow != window) {
                   return;
                 }
@@ -1364,7 +1364,11 @@ this.tabs = class extends ExtensionAPIPersistent {
           }
           filename = DownloadPaths.sanitize(filename);
 
-          picker.init(activeTab.ownerGlobal, title, Ci.nsIFilePicker.modeSave);
+          picker.init(
+            activeTab.ownerGlobal.browsingContext,
+            title,
+            Ci.nsIFilePicker.modeSave
+          );
           picker.appendFilter("PDF", "*.pdf");
           picker.defaultExtension = "pdf";
           picker.defaultString = filename;
diff --git a/browser/components/extensions/parent/ext-topSites.js b/browser/components/extensions/parent/ext-topSites.js
index 1400a7c236..6ef6a49287 100644
--- a/browser/components/extensions/parent/ext-topSites.js
+++ b/browser/components/extensions/parent/ext-topSites.js
@@ -19,7 +19,7 @@ const TOPSITES_FEED_PREF =
   "browser.newtabpage.activity-stream.feeds.system.topsites";
 
 this.topSites = class extends ExtensionAPI {
-  getAPI(context) {
+  getAPI() {
     return {
       topSites: {
         get: async function (options) {
diff --git a/browser/components/extensions/parent/ext-url-overrides.js b/browser/components/extensions/parent/ext-url-overrides.js
index cff36a8762..5be610a637 100644
--- a/browser/components/extensions/parent/ext-url-overrides.js
+++ b/browser/components/extensions/parent/ext-url-overrides.js
@@ -150,7 +150,7 @@ this.urlOverrides = class extends ExtensionAPI {
     }
   }
 
-  async onManifestEntry(entryName) {
+  async onManifestEntry() {
     let { extension } = this;
     let { manifest } = extension;
 
diff --git a/browser/components/extensions/parent/ext-windows.js b/browser/components/extensions/parent/ext-windows.js
index 3691ecdf56..cd715c0a3e 100644
--- a/browser/components/extensions/parent/ext-windows.js
+++ b/browser/components/extensions/parent/ext-windows.js
@@ -112,7 +112,7 @@ this.windows = class extends ExtensionAPIPersistent {
       // Keep track of the last windowId used to fire an onFocusChanged event
       let lastOnFocusChangedWindowId;
 
-      let listener = event => {
+      let listener = () => {
         // Wait a tick to avoid firing a superfluous WINDOW_ID_NONE
         // event when switching focus between two Firefox windows.
         Promise.resolve().then(() => {
diff --git a/browser/components/extensions/test/AppUiTestDelegate.sys.mjs b/browser/components/extensions/test/AppUiTestDelegate.sys.mjs
index f68392800d..6bfb36bfd9 100644
--- a/browser/components/extensions/test/AppUiTestDelegate.sys.mjs
+++ b/browser/components/extensions/test/AppUiTestDelegate.sys.mjs
@@ -112,7 +112,7 @@ async function promisePopupShown(popup) {
     if (popup.state == "open") {
       resolve();
     } else {
-      let onPopupShown = event => {
+      let onPopupShown = () => {
         popup.removeEventListener("popupshown", onPopupShown);
         resolve();
       };
@@ -129,7 +129,7 @@ function awaitBrowserLoaded(browser) {
     return Promise.resolve();
   }
   return new Promise(resolve => {
-    const listener = ev => {
+    const listener = () => {
       if (browser.currentURI.spec === "about:blank") {
         return;
       }
diff --git a/browser/components/extensions/test/browser/browser.toml b/browser/components/extensions/test/browser/browser.toml
index c185ebd4e7..417bad7e31 100644
--- a/browser/components/extensions/test/browser/browser.toml
+++ b/browser/components/extensions/test/browser/browser.toml
@@ -49,7 +49,7 @@ support-files = [
   "../../../../../toolkit/components/reader/test/readerModeNonArticle.html",
   "../../../../../toolkit/components/reader/test/readerModeArticle.html",
 ]
-skip-if = ["os == 'linux' && asan"] # Bug 1721945 - Software WebRender
+skip-if = ["os == 'linux' && os_version == '18.04' && asan"] # Bug 1721945 - Software WebRender
 
 ["browser_AMBrowserExtensionsImport.js"]
 
@@ -75,12 +75,12 @@ disabled = "bug 1438663 # same focus issue as Bug 1438663"
 ["browser_ext_browserAction_context.js"]
 https_first_disabled = true
 skip-if = [
-  "os == 'linux' && debug", # Bug 1504096
-  "os == 'linux' && socketprocess_networking",
+  "os == 'linux' && os_version == '18.04' && debug", # Bug 1504096
+  "os == 'linux' && os_version == '18.04' && socketprocess_networking",
 ]
 
 ["browser_ext_browserAction_contextMenu.js"]
-skip-if = ["os == 'linux'"] # bug 1369197
+skip-if = ["os == 'linux' && os_version == '18.04'"] # bug 1369197
 
 ["browser_ext_browserAction_disabled.js"]
 
@@ -132,8 +132,9 @@ skip-if = ["debug"] # Bug 1522164
 
 ["browser_ext_commands_execute_page_action.js"]
 skip-if = [
-  "verify && os == 'linux'",
-  "verify && os == 'mac'",
+  "os == 'linux' && os_version == '18.04' && verify",
+  "apple_catalina && verify",
+  "apple_silicon && verify",
 ]
 
 ["browser_ext_commands_execute_sidebar_action.js"]
@@ -230,8 +231,9 @@ support-files = ["../../../../../devtools/client/inspector/extensions/test/head_
 ["browser_ext_find.js"]
 https_first_disabled = true
 skip-if = [
-  "verify && os == 'linux'",
-  "verify && os == 'mac'",
+  "os == 'linux' && os_version == '18.04' && verify",
+  "apple_catalina && verify",
+  "apple_silicon && verify",
 ]
 
 ["browser_ext_getViews.js"]
@@ -303,8 +305,9 @@ https_first_disabled = true
 
 ["browser_ext_openPanel.js"]
 skip-if = [
-  "verify && !debug && os == 'linux'",
-  "verify && !debug && os == 'mac'",
+  "os == 'linux' && os_version == '18.04' && !debug && verify",
+  "apple_catalina && !debug && verify",
+  "apple_silicon && !debug && verify",
 ]
 
 ["browser_ext_optionsPage_activity.js"]
@@ -328,14 +331,17 @@ https_first_disabled = true
 
 ["browser_ext_pageAction_context.js"]
 https_first_disabled = true
-skip-if = ["verify && !debug && os == 'linux'"]
+skip-if = ["os == 'linux' && os_version == '18.04' && !debug && verify"]
 
 ["browser_ext_pageAction_contextMenu.js"]
 
 ["browser_ext_pageAction_popup.js"]
 
 ["browser_ext_pageAction_popup_resize.js"]
-skip-if = ["verify && debug && os == 'mac'"]
+skip-if = [
+  "apple_catalina && debug && verify",
+  "apple_silicon && debug && verify",
+]
 
 ["browser_ext_pageAction_show_matches.js"]
 https_first_disabled = true
@@ -487,8 +493,9 @@ https_first_disabled = true
 ["browser_ext_tabs_discard_reversed.js"]
 https_first_disabled = true
 skip-if = [
-  "os == 'mac'", # Bug 1722607
-  "os == 'linux' && debug", #Bug 1722607
+  "apple_silicon", # Bug 1722607
+  "apple_catalina", # Bug 1722607
+  "os == 'linux' && os_version == '18.04' && debug", #Bug 1722607
 ]
 
 ["browser_ext_tabs_discarded.js"]
@@ -641,7 +648,10 @@ https_first_disabled = true
 ["browser_ext_webRequest_error_after_stopped_or_closed.js"]
 
 ["browser_ext_webrtc.js"]
-skip-if = ["os == 'mac'"] # Bug 1565738
+skip-if = [
+  "apple_catalina", # Bug 1565738
+  "apple_silicon", # Bug 1565738
+]
 
 ["browser_ext_windows.js"]
 https_first_disabled = true
@@ -650,7 +660,10 @@ https_first_disabled = true
 https_first_disabled = true
 
 ["browser_ext_windows_create.js"]
-skip-if = ["verify && os == 'mac'"]
+skip-if = [
+  "apple_catalina && verify",
+  "apple_silicon && verify",
+]
 tags = "fullscreen"
 
 ["browser_ext_windows_create_cookieStoreId.js"]
@@ -670,13 +683,15 @@ https_first_disabled = true
 
 ["browser_ext_windows_size.js"]
 skip-if = [
-  "os == 'mac'",
+  "apple_catalina",
+  "apple_silicon",
   "os == 'linux' && os_version == '18.04' && debug", # Fails when windows are randomly opened in fullscreen mode, Bug 1638027
 ]
 
 ["browser_ext_windows_update.js"]
 skip-if = [
-  "verify && os == 'mac'",
+  "apple_catalina && verify",
+  "apple_silicon && verify",
   "os == 'mac' && os_version == '10.15' && debug", # Bug 1780998
   "os == 'linux' && os_version == '18.04'", # Bug 1533982 for linux1804
 ]
diff --git a/browser/components/extensions/test/browser/browser_AMBrowserExtensionsImport.js b/browser/components/extensions/test/browser/browser_AMBrowserExtensionsImport.js
index a680edb454..515875daac 100644
--- a/browser/components/extensions/test/browser/browser_AMBrowserExtensionsImport.js
+++ b/browser/components/extensions/test/browser/browser_AMBrowserExtensionsImport.js
@@ -43,7 +43,7 @@ const ADDON_SEARCH_RESULTS = {};
 
 const mockAddonRepository = ({ addons = [] }) => {
   return {
-    async getMappedAddons(browserID, extensionIDs) {
+    async getMappedAddons() {
       return Promise.resolve({
         addons,
         matchedIDs: [],
@@ -136,7 +136,7 @@ add_task(async function test_appmenu_notification() {
     "expected a notification about the imported add-ons"
   );
 
-  const endedPromises = result.importedAddonIDs.map(id =>
+  const endedPromises = result.importedAddonIDs.map(() =>
     AddonTestUtils.promiseInstallEvent("onInstallEnded")
   );
   const menuPanelHidden = BrowserTestUtils.waitForEvent(
diff --git a/browser/components/extensions/test/browser/browser_ExtensionControlledPopup.js b/browser/components/extensions/test/browser/browser_ExtensionControlledPopup.js
index 2e1e178215..11a3058444 100644
--- a/browser/components/extensions/test/browser/browser_ExtensionControlledPopup.js
+++ b/browser/components/extensions/test/browser/browser_ExtensionControlledPopup.js
@@ -13,7 +13,7 @@ ChromeUtils.defineESModuleGetters(this, {
     "resource://gre/modules/ExtensionSettingsStore.sys.mjs",
 });
 
-function createMarkup(doc, popup) {
+function createMarkup(doc) {
   let panel = ExtensionControlledPopup._getAndMaybeCreatePanel(doc);
   let popupnotification = doc.createXULElement("popupnotification");
   let attributes = {
@@ -98,7 +98,7 @@ add_task(async function testExtensionControlledPopup() {
     return popupShown;
   }
 
-  function closePopupWithAction(action, extensionId) {
+  function closePopupWithAction(action) {
     let done;
     if (action == "ignore") {
       panel.hidePopup();
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_click_types.js b/browser/components/extensions/test/browser/browser_ext_browserAction_click_types.js
index 6614bb62c2..e891901ed9 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_click_types.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_click_types.js
@@ -145,7 +145,7 @@ async function test_clickData_reset({ manifest_version }) {
         browser.test.sendMessage("onClick", info);
       }
 
-      function onPageActionClicked(tab, info) {
+      function onPageActionClicked() {
         browser.test.sendMessage("open-popup");
       }
 
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_context.js b/browser/components/extensions/test/browser/browser_ext_browserAction_context.js
index c1f8184c78..e5d315c5d2 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_context.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_context.js
@@ -258,7 +258,7 @@ let tabSwitchTestData = {
     "2.png": imageBuffer,
   },
 
-  getTests: function (tabs, windows) {
+  getTests: function (tabs) {
     let manifest = browser.runtime.getManifest();
     let { manifest_version } = manifest;
     const action = manifest_version < 3 ? "browserAction" : "action";
@@ -491,7 +491,7 @@ add_task(async function testDefaultTitle() {
       "icon.png": imageBuffer,
     },
 
-    getTests: function (tabs, windows) {
+    getTests: function (tabs) {
       let details = [
         {
           title: "Foo Extension",
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_contextMenu.js b/browser/components/extensions/test/browser/browser_ext_browserAction_contextMenu.js
index 9544ed43a4..8e89457904 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_contextMenu.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_contextMenu.js
@@ -452,7 +452,7 @@ async function browseraction_contextmenu_remove_extension_helper() {
     Services.prompt = prompt;
   });
 
-  async function testContextMenu(menuId, customizing) {
+  async function testContextMenu(menuId) {
     info(`Open browserAction context menu in ${menuId}`);
     let confirmArgs = promptService.confirmArgs();
     let menu = await openContextMenu(menuId, buttonId);
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_experiment.js b/browser/components/extensions/test/browser/browser_ext_browserAction_experiment.js
index d33553146e..dbf0b7efbd 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_experiment.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_experiment.js
@@ -49,7 +49,7 @@ let fooExperimentFiles = {
   /* globals ExtensionAPI */
   "parent.js": () => {
     this.foo = class extends ExtensionAPI {
-      getAPI(context) {
+      getAPI() {
         return {
           experiments: {
             foo: {
@@ -65,7 +65,7 @@ let fooExperimentFiles = {
 
   "child.js": () => {
     this.foo = class extends ExtensionAPI {
-      getAPI(context) {
+      getAPI() {
         return {
           experiments: {
             foo: {
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js b/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js
index 5a94a0dde1..71f615c91d 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon_permissions.js
@@ -21,7 +21,7 @@ add_task(async function testInvalidIconSizes() {
         let promises = [];
         for (let api of ["pageAction", "browserAction"]) {
           // helper function to run setIcon and check if it fails
-          let assertSetIconThrows = function (detail, error, message) {
+          let assertSetIconThrows = function (detail) {
             detail.tabId = tabId;
             browser.test.assertThrows(
               () => browser[api].setIcon(detail),
@@ -203,7 +203,7 @@ add_task(async function testSecureManifestURLsDenied() {
     for (let api of apis) {
       info(`TEST ${api} icon url: ${url}`);
 
-      let matchURLForbidden = url => ({
+      let matchURLForbidden = () => ({
         message: new RegExp(`match the format "strictRelativeUrl"`),
       });
 
diff --git a/browser/components/extensions/test/browser/browser_ext_browserAction_popup_preload.js b/browser/components/extensions/test/browser/browser_ext_browserAction_popup_preload.js
index 4c47c1b13b..c640f63ab7 100644
--- a/browser/components/extensions/test/browser/browser_ext_browserAction_popup_preload.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_popup_preload.js
@@ -136,7 +136,7 @@ add_task(async function testBrowserActionClickCanceled() {
     widget.node,
     "mouseup",
     false,
-    event => {
+    () => {
       isnot(browserAction.pendingPopup, null, "Pending popup was not cleared");
       isnot(
         browserAction.pendingPopupTimeout,
@@ -279,7 +279,7 @@ add_task(async function testBrowserActionDisabled() {
     widget.node,
     "mouseup",
     false,
-    event => {
+    () => {
       is(browserAction.pendingPopup, null, "Have no pending popup");
       is(
         browserAction.pendingPopupTimeout,
diff --git a/browser/components/extensions/test/browser/browser_ext_contextMenus.js b/browser/components/extensions/test/browser/browser_ext_contextMenus.js
index c816c89f82..77e4bf0827 100644
--- a/browser/components/extensions/test/browser/browser_ext_contextMenus.js
+++ b/browser/components/extensions/test/browser/browser_ext_contextMenus.js
@@ -391,7 +391,7 @@ add_task(async function () {
   checkClickInfo(result);
 
   // Select some text
-  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async function (arg) {
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], async function () {
     let doc = content.document;
     let range = doc.createRange();
     let selection = content.getSelection();
@@ -459,7 +459,7 @@ add_task(async function () {
   checkClickInfo(result);
 
   // Select a lot of text
-  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function (arg) {
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
     let doc = content.document;
     let range = doc.createRange();
     let selection = content.getSelection();
@@ -501,7 +501,7 @@ add_task(async function () {
 
   // Select a lot of text, excercise the editable element code path in
   // the Browser:GetSelection handler.
-  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function (arg) {
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
     let doc = content.document;
     let node = doc.getElementById("editabletext");
     // content.js handleContentContextMenu fails intermittently without focus.
diff --git a/browser/components/extensions/test/browser/browser_ext_contextMenus_bookmarks.js b/browser/components/extensions/test/browser/browser_ext_contextMenus_bookmarks.js
index 1e95899513..24411731f7 100644
--- a/browser/components/extensions/test/browser/browser_ext_contextMenus_bookmarks.js
+++ b/browser/components/extensions/test/browser/browser_ext_contextMenus_bookmarks.js
@@ -20,7 +20,7 @@ function bookmarkContextMenuExtension() {
         {
           title: CONTEXT_ENTRY_LABEL,
           contexts: ["bookmark"],
-          onclick: (info, tab) => {
+          onclick: info => {
             browser.test.sendMessage(`clicked`, info.bookmarkId);
           },
         },
diff --git a/browser/components/extensions/test/browser/browser_ext_contextMenus_commands.js b/browser/components/extensions/test/browser/browser_ext_contextMenus_commands.js
index 5a8f1db208..d643dda663 100644
--- a/browser/components/extensions/test/browser/browser_ext_contextMenus_commands.js
+++ b/browser/components/extensions/test/browser/browser_ext_contextMenus_commands.js
@@ -25,7 +25,7 @@ add_task(async function test_actions_context_menu() {
       contexts: ["all"],
       command: "_execute_sidebar_action",
     });
-    browser.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
+    browser.tabs.onUpdated.addListener(tabId => {
       browser.pageAction.show(tabId);
     });
     browser.contextMenus.onClicked.addListener(() => {
diff --git a/browser/components/extensions/test/browser/browser_ext_contextMenus_targetUrlPatterns.js b/browser/components/extensions/test/browser/browser_ext_contextMenus_targetUrlPatterns.js
index b28487064f..0f353600d7 100644
--- a/browser/components/extensions/test/browser/browser_ext_contextMenus_targetUrlPatterns.js
+++ b/browser/components/extensions/test/browser/browser_ext_contextMenus_targetUrlPatterns.js
@@ -72,7 +72,7 @@ add_task(async function unsupportedSchemes() {
     },
   ];
 
-  async function testScript(testcases) {
+  async function testScript() {
     let testcase;
 
     browser.contextMenus.onShown.addListener(({ menuIds, linkUrl }) => {
diff --git a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow.js b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow.js
index 0cfcb33ab3..55acbadad4 100644
--- a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow.js
@@ -464,7 +464,7 @@ add_task(async function test_devtools_inspectedWindow_eval_target_lifecycle() {
   );
 
   function devtools_page() {
-    browser.test.onMessage.addListener(async (msg, ...args) => {
+    browser.test.onMessage.addListener(async msg => {
       if (msg !== "inspectedWindow-eval-requests") {
         browser.test.fail(`Unexpected test message received: ${msg}`);
         return;
diff --git a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js
index a5f910e698..f0aeb891fd 100644
--- a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_eval_bindings.js
@@ -231,7 +231,7 @@ add_task(async function test_devtools_inspectedWindow_eval_bindings() {
       info("Waiting for the object properties to be displayed");
       // If this is the case, we wait for the properties to be fetched and displayed.
       await new Promise(resolve => {
-        const observer = new MutationObserver(mutations => {
+        const observer = new MutationObserver(() => {
           resolve();
           observer.disconnect();
         });
diff --git a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_reload.js b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_reload.js
index 9f7d452a2c..116d063f50 100644
--- a/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_reload.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_inspectedWindow_reload.js
@@ -270,7 +270,7 @@ add_task(
       background,
       devtoolsPage,
       closeToolbox: false,
-      testCase: async function (extension, tab, toolbox) {
+      testCase: async function (extension, tab) {
         info("Get the initial user agent");
         const initialUserAgent = await SpecialPowers.spawn(
           gBrowser.selectedBrowser,
diff --git a/browser/components/extensions/test/browser/browser_ext_devtools_page.js b/browser/components/extensions/test/browser/browser_ext_devtools_page.js
index 8f2700c657..492825965a 100644
--- a/browser/components/extensions/test/browser/browser_ext_devtools_page.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_page.js
@@ -202,11 +202,11 @@ add_task(async function test_devtools_page_and_extension_tab_messaging() {
   }
 
   function devtools_page() {
-    browser.runtime.onConnect.addListener(port => {
+    browser.runtime.onConnect.addListener(() => {
       browser.test.sendMessage("devtools_page_onconnect");
     });
 
-    browser.runtime.onMessage.addListener((msg, sender) => {
+    browser.runtime.onMessage.addListener(() => {
       browser.test.sendMessage("devtools_page_onmessage");
     });
 
diff --git a/browser/components/extensions/test/browser/browser_ext_menus_accesskey.js b/browser/components/extensions/test/browser/browser_ext_menus_accesskey.js
index 88c89902ac..8424dc2813 100644
--- a/browser/components/extensions/test/browser/browser_ext_menus_accesskey.js
+++ b/browser/components/extensions/test/browser/browser_ext_menus_accesskey.js
@@ -185,7 +185,7 @@ add_task(async function accesskeys_selection() {
   await extension.startup();
 
   // Select all
-  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function (arg) {
+  await SpecialPowers.spawn(gBrowser.selectedBrowser, [], function () {
     let doc = content.document;
     let range = doc.createRange();
     let selection = content.getSelection();
diff --git a/browser/components/extensions/test/browser/browser_ext_menus_targetElement.js b/browser/components/extensions/test/browser/browser_ext_menus_targetElement.js
index abfbf26a05..4fc9ebba82 100644
--- a/browser/components/extensions/test/browser/browser_ext_menus_targetElement.js
+++ b/browser/components/extensions/test/browser/browser_ext_menus_targetElement.js
@@ -29,7 +29,7 @@ async function loadExtensionAndTab() {
   }
 
   async function background() {
-    browser.menus.onShown.addListener(async (info, tab) => {
+    browser.menus.onShown.addListener(async info => {
       browser.test.sendMessage("onShownMenu", info.targetElementId);
     });
     await browser.tabs.executeScript({ file: "contentScript.js" });
@@ -79,7 +79,7 @@ add_task(async function required_permission() {
   // Load another extension to verify that the permission from the first
   // extension does not enable the "targetElementId" parameter.
   function background() {
-    browser.contextMenus.onShown.addListener((info, tab) => {
+    browser.contextMenus.onShown.addListener(info => {
       browser.test.assertEq(
         undefined,
         info.targetElementId,
diff --git a/browser/components/extensions/test/browser/browser_ext_mousewheel_zoom.js b/browser/components/extensions/test/browser/browser_ext_mousewheel_zoom.js
index d558400a7e..9c5f447a76 100644
--- a/browser/components/extensions/test/browser/browser_ext_mousewheel_zoom.js
+++ b/browser/components/extensions/test/browser/browser_ext_mousewheel_zoom.js
@@ -40,7 +40,7 @@ async function test_mousewheel_zoom(test) {
 
   function contentScript() {
     // eslint-disable-next-line mozilla/balanced-listeners
-    document.addEventListener("mousedown", e => {
+    document.addEventListener("mousedown", () => {
       // Send the zoom level back as a "zoom" message.
       const zoom = SpecialPowers.getFullZoom(window).toFixed(2);
       browser.test.sendMessage("zoom", zoom);
@@ -49,7 +49,7 @@ async function test_mousewheel_zoom(test) {
 
   function sidebarContentScript() {
     // eslint-disable-next-line mozilla/balanced-listeners
-    document.addEventListener("mousedown", e => {
+    document.addEventListener("mousedown", () => {
       // Send the zoom level back as a "zoom" message.
       const zoom = SpecialPowers.getFullZoom(window).toFixed(2);
       browser.test.sendMessage("zoom", zoom);
diff --git a/browser/components/extensions/test/browser/browser_ext_openPanel.js b/browser/components/extensions/test/browser/browser_ext_openPanel.js
index 105cdc834b..ed96bf2520 100644
--- a/browser/components/extensions/test/browser/browser_ext_openPanel.js
+++ b/browser/components/extensions/test/browser/browser_ext_openPanel.js
@@ -4,7 +4,7 @@
 
 add_task(async function test_openPopup_requires_user_interaction() {
   async function backgroundScript() {
-    browser.tabs.onUpdated.addListener(async (tabId, changeInfo, tabInfo) => {
+    browser.tabs.onUpdated.addListener(async (tabId, changeInfo) => {
       if (changeInfo.status != "complete") {
         return;
       }
diff --git a/browser/components/extensions/test/browser/browser_ext_optionsPage_modals.js b/browser/components/extensions/test/browser/browser_ext_optionsPage_modals.js
index 809a5605c0..0c3d150c91 100644
--- a/browser/components/extensions/test/browser/browser_ext_optionsPage_modals.js
+++ b/browser/components/extensions/test/browser/browser_ext_optionsPage_modals.js
@@ -2,6 +2,41 @@
 /* vim: set sts=2 sw=2 et tw=80: */
 "use strict";
 
+const { PromptTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/PromptTestUtils.sys.mjs"
+);
+
+async function waitForExtensionModalPrompt(extension) {
+  const dialog = await PromptTestUtils.waitForPrompt(gBrowser.selectedBrowser, {
+    modalType: Ci.nsIPrompt.MODAL_TYPE_CONTENT,
+  });
+  ok(dialog, "Got an active modal prompt dialog as expected");
+  Assert.equal(
+    dialog?.args.promptPrincipal.addonId,
+    extension.id,
+    "Got a prompt associated to the expected extension id"
+  );
+
+  const promptTitle = dialog?.ui.infoTitle.textContent;
+  ok(
+    /The page at TestExtName says:/.test(promptTitle),
+    `Got the expect title on the modal prompt dialog: "${promptTitle}"`
+  );
+
+  return {
+    async closeModalPrompt() {
+      info("Close the tab modal prompt");
+      await PromptTestUtils.handlePrompt(dialog);
+    },
+    assertClosedModalPrompt() {
+      ok(
+        !dialog.args.promptActive,
+        "modal prompt dialog has been closed as expected"
+      );
+    },
+  };
+}
+
 add_task(async function test_tab_options_modals() {
   function backgroundScript() {
     browser.runtime.openOptionsPage();
@@ -26,6 +61,7 @@ add_task(async function test_tab_options_modals() {
       options_ui: {
         page: "options.html",
       },
+      name: "TestExtName",
     },
     files: {
       "options.html": `<!DOCTYPE html>
@@ -42,57 +78,15 @@ add_task(async function test_tab_options_modals() {
 
   await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:addons");
 
+  const testPromptPromise = waitForExtensionModalPrompt(extension);
   await extension.startup();
 
-  const onceModalOpened = new Promise(resolve => {
-    const aboutAddonsBrowser = gBrowser.selectedBrowser;
-
-    aboutAddonsBrowser.addEventListener(
-      "DOMWillOpenModalDialog",
-      function onModalDialog(event) {
-        // Wait for the next event tick to make sure the remaining part of the
-        // testcase runs after the dialog gets opened.
-        SimpleTest.executeSoon(resolve);
-      },
-      { once: true, capture: true }
-    );
-  });
-
   info("Wait the options_ui modal to be opened");
-  await onceModalOpened;
-
-  const optionsBrowser = getInlineOptionsBrowser(gBrowser.selectedBrowser);
-
-  // The stack that contains the tabmodalprompt elements is the parent of
-  // the extensions options_ui browser element.
-  let stack = optionsBrowser.parentNode;
-
-  let dialogs = stack.querySelectorAll("tabmodalprompt");
-  Assert.equal(
-    dialogs.length,
-    1,
-    "Expect a tab modal opened for the about addons tab"
-  );
-
-  // Verify that the expected stylesheets have been applied on the
-  // tabmodalprompt element (See Bug 1550529).
-  const tabmodalStyle = dialogs[0].ownerGlobal.getComputedStyle(dialogs[0]);
-  is(
-    tabmodalStyle["background-color"],
-    "rgba(26, 26, 26, 0.5)",
-    "Got the expected styles applied to the tabmodalprompt"
-  );
-
-  info("Close the tab modal prompt");
-  dialogs[0].querySelector(".tabmodalprompt-button0").click();
+  const testModalPrompt = await testPromptPromise;
 
+  testModalPrompt.closeModalPrompt();
   await extension.awaitFinish("options-ui-modals");
-
-  Assert.equal(
-    stack.querySelectorAll("tabmodalprompt").length,
-    0,
-    "Expect the tab modal to be closed"
-  );
+  testModalPrompt.assertClosedModalPrompt();
 
   BrowserTestUtils.removeTab(gBrowser.selectedTab);
 
diff --git a/browser/components/extensions/test/browser/browser_ext_pageAction_click_types.js b/browser/components/extensions/test/browser/browser_ext_pageAction_click_types.js
index 0168ea0ab2..0ca9be6bfa 100644
--- a/browser/components/extensions/test/browser/browser_ext_pageAction_click_types.js
+++ b/browser/components/extensions/test/browser/browser_ext_pageAction_click_types.js
@@ -146,7 +146,7 @@ async function test_clickData_reset(testAsNonPersistent = false) {
 
     files: {
       "background.js": async function background() {
-        function onBrowserActionClicked(tab, info) {
+        function onBrowserActionClicked() {
           // openPopup requires user interaction, such as a browser action click.
           browser.pageAction.openPopup();
         }
diff --git a/browser/components/extensions/test/browser/browser_ext_popup_focus.js b/browser/components/extensions/test/browser/browser_ext_popup_focus.js
index 4cf46f2be5..16e4f05dbb 100644
--- a/browser/components/extensions/test/browser/browser_ext_popup_focus.js
+++ b/browser/components/extensions/test/browser/browser_ext_popup_focus.js
@@ -22,7 +22,7 @@ add_task(async function testPageActionFocus() {
       "popup.js": function () {
         window.addEventListener(
           "focus",
-          event => {
+          () => {
             browser.test.log("extension popup received focus event");
             browser.test.assertEq(
               true,
@@ -63,7 +63,7 @@ add_task(async function testBrowserActionFocus() {
       "popup.js": function () {
         window.addEventListener(
           "focus",
-          event => {
+          () => {
             browser.test.log("extension popup received focus event");
             browser.test.assertEq(
               true,
diff --git a/browser/components/extensions/test/browser/browser_ext_search_favicon.js b/browser/components/extensions/test/browser/browser_ext_search_favicon.js
index 4e48dd55fa..474ab37e20 100644
--- a/browser/components/extensions/test/browser/browser_ext_search_favicon.js
+++ b/browser/components/extensions/test/browser/browser_ext_search_favicon.js
@@ -25,18 +25,18 @@ server.registerPathHandler("/ico.png", (request, response) => {
   response.write(atob(HTTP_ICON_DATA));
 });
 
-function promiseEngineIconLoaded(engineName) {
-  return TestUtils.topicObserved(
+async function promiseEngineIconLoaded(engineName) {
+  await TestUtils.topicObserved(
     "browser-search-engine-modified",
     (engine, verb) => {
       engine.QueryInterface(Ci.nsISearchEngine);
-      return (
-        verb == "engine-changed" &&
-        engine.name == engineName &&
-        engine.getIconURL()
-      );
+      return verb == "engine-changed" && engine.name == engineName;
     }
   );
+  Assert.ok(
+    await Services.search.getEngineByName(engineName).getIconURL(),
+    "Should have a valid icon URL"
+  );
 }
 
 add_task(async function test_search_favicon() {
diff --git a/browser/components/extensions/test/browser/browser_ext_sessions_getRecentlyClosed_tabs.js b/browser/components/extensions/test/browser/browser_ext_sessions_getRecentlyClosed_tabs.js
index 4a513f5131..71c30ccf5b 100644
--- a/browser/components/extensions/test/browser/browser_ext_sessions_getRecentlyClosed_tabs.js
+++ b/browser/components/extensions/test/browser/browser_ext_sessions_getRecentlyClosed_tabs.js
@@ -247,7 +247,7 @@ add_task(
     info("Open the non web controlled page in _blank target");
     let onNewTabOpened = new Promise(resolve =>
       win.gBrowser.addTabsProgressListener({
-        onStateChange(browser, webProgress, request, stateFlags, status) {
+        onStateChange(browser, webProgress, request, stateFlags) {
           if (stateFlags & Ci.nsIWebProgressListener.STATE_START) {
             win.gBrowser.removeTabsProgressListener(this);
             resolve(win.gBrowser.getTabForBrowser(browser));
diff --git a/browser/components/extensions/test/browser/browser_ext_sessions_restore.js b/browser/components/extensions/test/browser/browser_ext_sessions_restore.js
index 39057519ed..1006fab89a 100644
--- a/browser/components/extensions/test/browser/browser_ext_sessions_restore.js
+++ b/browser/components/extensions/test/browser/browser_ext_sessions_restore.js
@@ -27,7 +27,7 @@ add_task(async function test_sessions_restore() {
         });
       } else if (msg == "restore-reject") {
         browser.sessions.restore("not-a-valid-session-id").then(
-          sessions => {
+          () => {
             browser.test.fail("restore rejected with an invalid sessionId");
           },
           error => {
diff --git a/browser/components/extensions/test/browser/browser_ext_sessions_restoreTab.js b/browser/components/extensions/test/browser/browser_ext_sessions_restoreTab.js
index 679e1fbd6c..c89e9d39dc 100644
--- a/browser/components/extensions/test/browser/browser_ext_sessions_restoreTab.js
+++ b/browser/components/extensions/test/browser/browser_ext_sessions_restoreTab.js
@@ -16,7 +16,7 @@ ChromeUtils.defineESModuleGetters(this, {
 add_task(async function test_restoringModifiedTab() {
   function background() {
     browser.tabs.create({ url: "http://example.com/" });
-    browser.test.onMessage.addListener((msg, filter) => {
+    browser.test.onMessage.addListener(msg => {
       if (msg == "change-tab") {
         browser.tabs.executeScript({ code: 'location.href += "?changedTab";' });
       }
@@ -83,7 +83,7 @@ add_task(async function test_restoringModifiedTab() {
 
 add_task(async function test_restoringClosedTabWithTooLargeIndex() {
   function background() {
-    browser.test.onMessage.addListener(async (msg, filter) => {
+    browser.test.onMessage.addListener(async msg => {
       if (msg != "restoreTab") {
         return;
       }
diff --git a/browser/components/extensions/test/browser/browser_ext_sessions_window_tab_value.js b/browser/components/extensions/test/browser/browser_ext_sessions_window_tab_value.js
index b21b59fe8c..f6482ed709 100644
--- a/browser/components/extensions/test/browser/browser_ext_sessions_window_tab_value.js
+++ b/browser/components/extensions/test/browser/browser_ext_sessions_window_tab_value.js
@@ -134,7 +134,7 @@ add_task(async function test_sessions_tab_value_persistence() {
     // Wait until the newly created tab has completed loading or it will still have
     // about:blank url when it gets removed and will not appear in the removed tabs history.
     browser.webNavigation.onCompleted.addListener(
-      async function newTabListener(details) {
+      async function newTabListener() {
         browser.webNavigation.onCompleted.removeListener(newTabListener);
 
         let tabs = await browser.tabs.query({ currentWindow: true });
diff --git a/browser/components/extensions/test/browser/browser_ext_settings_overrides_default_search.js b/browser/components/extensions/test/browser/browser_ext_settings_overrides_default_search.js
index 74eaa6e634..083f6be393 100644
--- a/browser/components/extensions/test/browser/browser_ext_settings_overrides_default_search.js
+++ b/browser/components/extensions/test/browser/browser_ext_settings_overrides_default_search.js
@@ -7,6 +7,7 @@ ChromeUtils.defineESModuleGetters(this, {
   AddonManager: "resource://gre/modules/AddonManager.sys.mjs",
   AddonTestUtils: "resource://testing-common/AddonTestUtils.sys.mjs",
   SearchTestUtils: "resource://testing-common/SearchTestUtils.sys.mjs",
+  SearchUtils: "resource://gre/modules/SearchUtils.sys.mjs",
   TelemetryTestUtils: "resource://testing-common/TelemetryTestUtils.sys.mjs",
 });
 
@@ -21,14 +22,19 @@ SearchTestUtils.init(this);
 const DEFAULT_ENGINE = {
   id: "basic",
   name: "basic",
-  loadPath: "[addon]basic@search.mozilla.org",
-  submissionUrl:
-    "https://mochi.test:8888/browser/browser/components/search/test/browser/?search=&foo=1",
+  loadPath: SearchUtils.newSearchConfigEnabled
+    ? "[app]basic@search.mozilla.org"
+    : "[addon]basic@search.mozilla.org",
+  submissionUrl: SearchUtils.newSearchConfigEnabled
+    ? "https://mochi.test:8888/browser/browser/components/search/test/browser/?foo=1&search="
+    : "https://mochi.test:8888/browser/browser/components/search/test/browser/?search=&foo=1",
 };
 const ALTERNATE_ENGINE = {
   id: "simple",
   name: "Simple Engine",
-  loadPath: "[addon]simple@search.mozilla.org",
+  loadPath: SearchUtils.newSearchConfigEnabled
+    ? "[app]simple@search.mozilla.org"
+    : "[addon]simple@search.mozilla.org",
   submissionUrl: "https://example.com/?sourceId=Mozilla-search&search=",
 };
 const ALTERNATE2_ENGINE = {
@@ -97,7 +103,11 @@ add_setup(async function () {
   await SearchTestUtils.useMochitestEngines(searchExtensions);
 
   SearchTestUtils.useMockIdleService();
-  let response = await fetch(`resource://search-extensions/engines.json`);
+  let response = await fetch(
+    SearchUtils.newSearchConfigEnabled
+      ? `resource://search-extensions/search-config-v2.json`
+      : `resource://search-extensions/engines.json`
+  );
   let json = await response.json();
   await SearchTestUtils.updateRemoteSettingsConfig(json.data);
 
diff --git a/browser/components/extensions/test/browser/browser_ext_sidebarAction.js b/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
index afc1e4f9b9..8498f73071 100644
--- a/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
+++ b/browser/components/extensions/test/browser/browser_ext_sidebarAction.js
@@ -204,14 +204,16 @@ add_task(async function sidebar_isOpen() {
 });
 
 add_task(async function testShortcuts() {
-  function verifyShortcut(id, commandKey) {
+  function verifyShortcut(id, commandKey, win = window) {
+    const doc = win.document;
     // We're just testing the command key since the modifiers have different
     // icons on different platforms.
-    let menuitem = document.getElementById(
+    let menuitem = doc.getElementById(
       `sidebarswitcher_menu_${makeWidgetId(id)}-sidebar-action`
     );
+    ok(menuitem, `Expect a menuitem for ${id}`);
     ok(menuitem.hasAttribute("key"), "The menu item has a key specified");
-    let key = document.getElementById(menuitem.getAttribute("key"));
+    let key = doc.getElementById(menuitem.getAttribute("key"));
     ok(key, "The key attribute finds the related key element");
     ok(
       menuitem.getAttribute("acceltext").endsWith(commandKey),
@@ -219,6 +221,16 @@ add_task(async function testShortcuts() {
     );
   }
 
+  async function toggleSwitcherPanel(win = window) {
+    // Open and close the switcher panel to trigger shortcut content rendering.
+    let switcherPanelShown = promisePopupShown(win.SidebarUI._switcherPanel);
+    win.SidebarUI.showSwitcherPanel();
+    await switcherPanelShown;
+    let switcherPanelHidden = promisePopupHidden(win.SidebarUI._switcherPanel);
+    win.SidebarUI.hideSwitcherPanel();
+    await switcherPanelHidden;
+  }
+
   let extension1 = ExtensionTestUtils.loadExtension(
     getExtData({
       commands: {
@@ -244,25 +256,48 @@ add_task(async function testShortcuts() {
 
   await extension1.startup();
   await extension1.awaitMessage("sidebar");
+  await extension2.startup();
+  await extension2.awaitMessage("sidebar");
 
-  // Open and close the switcher panel to trigger shortcut content rendering.
-  let switcherPanelShown = promisePopupShown(SidebarUI._switcherPanel);
-  SidebarUI.showSwitcherPanel();
-  await switcherPanelShown;
-  let switcherPanelHidden = promisePopupHidden(SidebarUI._switcherPanel);
-  SidebarUI.hideSwitcherPanel();
-  await switcherPanelHidden;
+  info("Open a second window");
+  const win = await BrowserTestUtils.openNewBrowserWindow();
+  info("Wait for extension2 sidebar to be open in the new window");
+  await extension2.awaitMessage("sidebar");
+
+  info("Toggle switcher panel");
+  await toggleSwitcherPanel();
+  await toggleSwitcherPanel(win);
 
   // Test that the key is set for the extension after the shortcuts are rendered.
   verifyShortcut(extension1.id, "I");
-
-  await extension2.startup();
-  await extension2.awaitMessage("sidebar");
+  verifyShortcut(extension1.id, "I", win);
 
   // Once the switcher panel has been opened new shortcuts should be added
   // automatically.
   verifyShortcut(extension2.id, "E");
+  verifyShortcut(extension2.id, "E", win);
+
+  // Regression test (see Bug 1881820).
+  info(
+    "Reload the addon and verify the sidebar shortcut still works as expected"
+  );
+  const addon = await AddonManager.getAddonByID(extension1.id);
+  await addon.reload();
+
+  const keysetId1 = `#ext-keyset-id-${makeWidgetId(extension1.id)}`;
+  Assert.equal(
+    window.document.querySelectorAll(keysetId1).length,
+    1,
+    "Expect no keyset leaked in the 1st window after addon reload"
+  );
+  Assert.equal(
+    win.document.querySelectorAll(keysetId1).length,
+    1,
+    "Expect no keyset leaked in the 2nd window after addon reload"
+  );
 
   await extension1.unload();
   await extension2.unload();
+
+  await BrowserTestUtils.closeWindow(win);
 });
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_autoDiscardable.js b/browser/components/extensions/test/browser/browser_ext_tabs_autoDiscardable.js
index 74043e2a3a..acca3638a0 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_autoDiscardable.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_autoDiscardable.js
@@ -23,7 +23,7 @@ add_task(async function test_autoDiscardable() {
       );
       const { ExtensionError } = ExtensionUtils;
       this.experiments = class extends ExtensionAPI {
-        getAPI(context) {
+        getAPI() {
           return {
             experiments: {
               async unload() {
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_discard_reversed.js b/browser/components/extensions/test/browser/browser_ext_tabs_discard_reversed.js
index 5fad30a6fb..753b9b67a6 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_discard_reversed.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_discard_reversed.js
@@ -44,7 +44,7 @@ add_task(async function tabs_discarded_load_and_discard() {
         title: [],
         url: [],
       };
-      function tabsOnUpdatedAfterLoad(tabId, changeInfo, tab) {
+      function tabsOnUpdatedAfterLoad(tabId, changeInfo) {
         browser.test.assertEq(TAB_ID, tabId, "tabId for tabs.onUpdated");
         for (let [prop, value] of Object.entries(changeInfo)) {
           observedChanges[prop].push(value);
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_duplicate.js b/browser/components/extensions/test/browser/browser_ext_tabs_duplicate.js
index 50c56ea796..f45b285311 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_duplicate.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_duplicate.js
@@ -46,7 +46,7 @@ add_task(async function testDuplicateTab() {
 add_task(async function testDuplicateTabLazily() {
   async function background() {
     let tabLoadComplete = new Promise(resolve => {
-      browser.test.onMessage.addListener((message, tabId, result) => {
+      browser.test.onMessage.addListener((message, tabId) => {
         if (message == "duplicate-tab-done") {
           resolve(tabId);
         }
@@ -55,11 +55,7 @@ add_task(async function testDuplicateTabLazily() {
 
     function awaitLoad(tabId) {
       return new Promise(resolve => {
-        browser.tabs.onUpdated.addListener(function listener(
-          tabId_,
-          changed,
-          tab
-        ) {
+        browser.tabs.onUpdated.addListener(function listener(tabId_, changed) {
           if (tabId == tabId_ && changed.status == "complete") {
             browser.tabs.onUpdated.removeListener(listener);
             resolve();
@@ -282,7 +278,7 @@ add_task(async function testDuplicateResolvePromiseRightAway() {
 
       let resolvedRightAway = true;
       browser.tabs.onUpdated.addListener(
-        (tabId, changeInfo, tab) => {
+        () => {
           resolvedRightAway = false;
         },
         { urls: [source.url] }
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_events.js b/browser/components/extensions/test/browser/browser_ext_tabs_events.js
index fe9317b4a6..f323d1e55d 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_events.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_events.js
@@ -211,7 +211,7 @@ add_task(async function test_tab_events_incognito_monitored() {
       // We have to explicitly wait for the event here, since its timing is
       // not predictable.
       let promiseAttached = new Promise(resolve => {
-        browser.tabs.onAttached.addListener(function listener(tabId) {
+        browser.tabs.onAttached.addListener(function listener() {
           browser.tabs.onAttached.removeListener(listener);
           resolve();
         });
@@ -427,11 +427,7 @@ add_task(async function testTabRemovalEvent() {
 
     function awaitLoad(tabId) {
       return new Promise(resolve => {
-        browser.tabs.onUpdated.addListener(function listener(
-          tabId_,
-          changed,
-          tab
-        ) {
+        browser.tabs.onUpdated.addListener(function listener(tabId_, changed) {
           if (tabId == tabId_ && changed.status == "complete") {
             browser.tabs.onUpdated.removeListener(listener);
             resolve();
@@ -440,7 +436,7 @@ add_task(async function testTabRemovalEvent() {
       });
     }
 
-    chrome.tabs.onRemoved.addListener((tabId, info) => {
+    chrome.tabs.onRemoved.addListener(tabId => {
       browser.test.assertEq(
         0,
         events.length,
@@ -466,7 +462,7 @@ add_task(async function testTabRemovalEvent() {
       let tab = await browser.tabs.create({ url: url });
       await awaitLoad(tab.id);
 
-      chrome.tabs.onActivated.addListener(info => {
+      chrome.tabs.onActivated.addListener(() => {
         browser.test.assertEq(
           1,
           events.length,
@@ -522,7 +518,7 @@ add_task(async function testTabCreateRelated() {
       );
       browser.test.fail("tabMoved was received");
     });
-    browser.tabs.onRemoved.addListener((tabId, info) => {
+    browser.tabs.onRemoved.addListener(tabId => {
       browser.test.assertEq(created, tabId, "removed id same as created");
       browser.test.sendMessage("tabRemoved");
     });
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_executeScript.js b/browser/components/extensions/test/browser/browser_ext_tabs_executeScript.js
index c02aef3da9..f79b67f779 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_executeScript.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_executeScript.js
@@ -77,7 +77,7 @@ add_task(async function testExecuteScript() {
             code: "42",
           })
           .then(
-            result => {
+            () => {
               browser.test.fail(
                 "Expected not to be able to execute a script with both file and code"
               );
@@ -208,7 +208,7 @@ add_task(async function testExecuteScript() {
             code: "window",
           })
           .then(
-            result => {
+            () => {
               browser.test.fail(
                 "Expected error when returning non-structured-clonable object"
               );
@@ -232,7 +232,7 @@ add_task(async function testExecuteScript() {
             code: "Promise.resolve(window)",
           })
           .then(
-            result => {
+            () => {
               browser.test.fail(
                 "Expected error when returning non-structured-clonable object"
               );
@@ -256,7 +256,7 @@ add_task(async function testExecuteScript() {
             file: "script3.js",
           })
           .then(
-            result => {
+            () => {
               browser.test.fail(
                 "Expected error when returning non-structured-clonable object"
               );
@@ -281,7 +281,7 @@ add_task(async function testExecuteScript() {
             code: "42",
           })
           .then(
-            result => {
+            () => {
               browser.test.fail(
                 "Expected error when specifying invalid frame ID"
               );
@@ -303,7 +303,7 @@ add_task(async function testExecuteScript() {
                 code: "42",
               })
               .then(
-                result => {
+                () => {
                   browser.test.fail(
                     "Expected error when trying to execute on invalid domain"
                   );
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_executeScript_good.js b/browser/components/extensions/test/browser/browser_ext_tabs_executeScript_good.js
index e9d008bf92..648a6f7e30 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_executeScript_good.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_executeScript_good.js
@@ -8,7 +8,7 @@ async function testHasPermission(params) {
   let contentSetup = params.contentSetup || (() => Promise.resolve());
 
   async function background(contentSetup) {
-    browser.runtime.onMessage.addListener((msg, sender) => {
+    browser.runtime.onMessage.addListener(msg => {
       browser.test.assertEq(msg, "script ran", "script ran");
       browser.test.notifyPass("executeScript");
     });
@@ -158,7 +158,7 @@ add_task(async function testGoodPermissions() {
       browser.contextMenus.create({ title: "activeTab", contexts: ["all"] });
       return Promise.resolve();
     },
-    setup: async function (extension) {
+    setup: async function () {
       let contextMenu = document.getElementById("contentAreaContextMenu");
       let awaitPopupShown = BrowserTestUtils.waitForEvent(
         contextMenu,
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_hide.js b/browser/components/extensions/test/browser/browser_ext_tabs_hide.js
index 89c50db692..cb7373451d 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_hide.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_hide.js
@@ -148,7 +148,7 @@ add_task(function test_doorhanger_disable() {
 
 add_task(async function test_tabs_showhide() {
   async function background() {
-    browser.test.onMessage.addListener(async (msg, data) => {
+    browser.test.onMessage.addListener(async msg => {
       switch (msg) {
         case "hideall": {
           let tabs = await browser.tabs.query({ hidden: false });
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_hide_update.js b/browser/components/extensions/test/browser/browser_ext_tabs_hide_update.js
index 7fbf185704..e840c0d640 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_hide_update.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_hide_update.js
@@ -28,7 +28,7 @@ function getExtension() {
     let tabs = await browser.tabs.query({ url: "http://example.com/" });
     let testTab = tabs[0];
 
-    browser.tabs.onUpdated.addListener((tabId, changeInfo, tab) => {
+    browser.tabs.onUpdated.addListener((tabId, changeInfo) => {
       if ("hidden" in changeInfo) {
         browser.test.assertEq(tabId, testTab.id, "correct tab was hidden");
         browser.test.assertTrue(changeInfo.hidden, "tab is hidden");
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_insertCSS.js b/browser/components/extensions/test/browser/browser_ext_tabs_insertCSS.js
index 1a4bbd0c74..374902f2f6 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_insertCSS.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_insertCSS.js
@@ -63,7 +63,7 @@ add_task(async function testExecuteScript() {
               code: "* { background: rgb(100, 100, 100) !important }",
               cssOrigin: "author",
             })
-            .then(r =>
+            .then(() =>
               browser.tabs.insertCSS({
                 code: "* { background: rgb(43, 43, 43) !important }",
                 cssOrigin: "author",
@@ -81,7 +81,7 @@ add_task(async function testExecuteScript() {
               code: "* { background: rgb(100, 100, 100) !important }",
               cssOrigin: "user",
             })
-            .then(r =>
+            .then(() =>
               browser.tabs.insertCSS({
                 code: "* { background: rgb(44, 44, 44) !important }",
                 cssOrigin: "author",
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_move_discarded.js b/browser/components/extensions/test/browser/browser_ext_tabs_move_discarded.js
index ebee4fbc90..5c7f7e7eb1 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_move_discarded.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_move_discarded.js
@@ -49,7 +49,7 @@ add_task(async function move_hidden_discarded_to_window() {
       // Listener with "urls" filter, regression test for
       // https://bugzilla.mozilla.org/show_bug.cgi?id=1695346
       browser.tabs.onUpdated.addListener(
-        (tabId, changeInfo, tab) => {
+        (tabId, changeInfo) => {
           browser.test.assertTrue(changeInfo.hidden, "tab was hidden");
           browser.test.sendMessage("onUpdated_urls_filter");
         },
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_newtab_private.js b/browser/components/extensions/test/browser/browser_ext_tabs_newtab_private.js
index 19146fbe42..8855078faa 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_newtab_private.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_newtab_private.js
@@ -9,7 +9,7 @@ const NEWTAB_EXTENSION_CONTROLLED = "browser.newtab.extensionControlled";
 const NEWTAB_URI = "webext-newtab-1.html";
 
 function promisePrefChange(pref) {
-  return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
     Services.prefs.addObserver(pref, function observer() {
       Services.prefs.removeObserver(pref, observer);
       resolve(arguments);
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_onCreated.js b/browser/components/extensions/test/browser/browser_ext_tabs_onCreated.js
index b48047abde..0004f60853 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_onCreated.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_onCreated.js
@@ -13,7 +13,7 @@ add_task(async function test_onCreated_active() {
         browser.tabs.remove(tab.id);
         browser.test.sendMessage("onCreated", tab);
       });
-      browser.tabs.onUpdated.addListener((tabId, changes, tab) => {
+      browser.tabs.onUpdated.addListener((tabId, changes) => {
         browser.test.assertEq(
           '["status"]',
           JSON.stringify(Object.keys(changes)),
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated.js b/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated.js
index a59fa21f8a..65c8c349cf 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated.js
@@ -267,7 +267,7 @@ add_task(async function test_onUpdated_after_onRemoved() {
 
       // If remove happens fast and we never receive onUpdated, that is ok, but
       // we never want to receive onUpdated after onRemoved.
-      browser.tabs.onUpdated.addListener(function onUpdated(tabId, changeInfo) {
+      browser.tabs.onUpdated.addListener(function onUpdated(tabId) {
         if (!tab || tab.id !== tabId) {
           return;
         }
@@ -277,7 +277,7 @@ add_task(async function test_onUpdated_after_onRemoved() {
         );
       });
 
-      browser.tabs.onRemoved.addListener((tabId, removedInfo) => {
+      browser.tabs.onRemoved.addListener(tabId => {
         if (!tab || tab.id !== tabId) {
           return;
         }
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated_filter.js b/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated_filter.js
index 83d305e491..ed5cf6c525 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated_filter.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_onUpdated_filter.js
@@ -23,7 +23,7 @@ add_task(async function test_filter_url() {
   let ext_perm = ExtensionTestUtils.loadExtension({
     background() {
       browser.tabs.onUpdated.addListener(
-        (tabId, changeInfo) => {
+        () => {
           browser.test.fail(
             `received unexpected onUpdated event without tabs permission`
           );
@@ -73,7 +73,7 @@ add_task(async function test_filter_url_activeTab() {
     },
     background() {
       browser.tabs.onUpdated.addListener(
-        (tabId, changeInfo) => {
+        () => {
           browser.test.fail(
             "should only have notification for activeTab, selectedTab is not activeTab"
           );
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_query.js b/browser/components/extensions/test/browser/browser_ext_tabs_query.js
index 099588c701..30c05a4b83 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_query.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_query.js
@@ -283,7 +283,7 @@ add_task(async function () {
     },
 
     background: function () {
-      browser.test.onMessage.addListener(async msg => {
+      browser.test.onMessage.addListener(async () => {
         let tabs = await browser.tabs.query({ active: true });
 
         browser.test.assertEq(tabs.length, 1, "should have one tab");
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_saveAsPDF.js b/browser/components/extensions/test/browser/browser_ext_tabs_saveAsPDF.js
index fdff1dddbf..7e33da8bed 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_saveAsPDF.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_saveAsPDF.js
@@ -30,7 +30,7 @@ async function testReturnStatus(expectedStatus) {
   }
 
   let MockFilePicker = SpecialPowers.MockFilePicker;
-  MockFilePicker.init(window);
+  MockFilePicker.init(window.browsingContext);
 
   if (expectedStatus == "replaced" || expectedStatus == "not_replaced") {
     MockFilePicker.returnValue = MockFilePicker.returnReplace;
@@ -42,7 +42,7 @@ async function testReturnStatus(expectedStatus) {
 
   MockFilePicker.displayDirectory = saveDir;
 
-  MockFilePicker.showCallback = fp => {
+  MockFilePicker.showCallback = () => {
     MockFilePicker.setFiles([saveFile]);
     MockFilePicker.filterIndex = 0; // *.* - all file extensions
   };
@@ -126,7 +126,7 @@ async function testFileName(expectedFileName) {
   }
 
   let MockFilePicker = SpecialPowers.MockFilePicker;
-  MockFilePicker.init(window);
+  MockFilePicker.init(window.browsingContext);
 
   MockFilePicker.returnValue = MockFilePicker.returnOK;
 
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_sendMessage.js b/browser/components/extensions/test/browser/browser_ext_tabs_sendMessage.js
index 8c420c2821..699ab8613a 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_sendMessage.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_sendMessage.js
@@ -19,7 +19,7 @@ add_task(async function tabsSendMessageReply() {
     background: async function () {
       let firstTab;
       let promiseResponse = new Promise(resolve => {
-        browser.runtime.onMessage.addListener((msg, sender, respond) => {
+        browser.runtime.onMessage.addListener((msg, sender) => {
           if (msg == "content-script-ready") {
             let tabId = sender.tab.id;
 
@@ -265,7 +265,7 @@ add_task(async function tabsSendHidden() {
 
     background: async function () {
       let resolveContent;
-      browser.runtime.onMessage.addListener((msg, sender) => {
+      browser.runtime.onMessage.addListener(msg => {
         if (msg[0] == "content-ready") {
           resolveContent(msg[1]);
         }
@@ -327,7 +327,7 @@ add_task(async function tabsSendHidden() {
         // properties of the possibly-hidden content window.
         let href = window.location.href;
 
-        browser.runtime.onMessage.addListener((msg, sender) => {
+        browser.runtime.onMessage.addListener(msg => {
           browser.test.assertEq(
             href,
             msg,
diff --git a/browser/components/extensions/test/browser/browser_ext_tabs_sharingState.js b/browser/components/extensions/test/browser/browser_ext_tabs_sharingState.js
index 47f2006307..86e6af2d6e 100644
--- a/browser/components/extensions/test/browser/browser_ext_tabs_sharingState.js
+++ b/browser/components/extensions/test/browser/browser_ext_tabs_sharingState.js
@@ -59,7 +59,7 @@ add_task(async function test_tabs_mediaIndicators() {
     tabs = await browser.tabs.query({ hidden: true });
     browser.test.assertEq(tabs.length, 0, "unable to hide sharing tab");
 
-    browser.tabs.onUpdated.addListener(async (tabId, changeInfo, tab) => {
+    browser.tabs.onUpdated.addListener(async (tabId, changeInfo) => {
       if (testTab.id !== tabId) {
         return;
       }
diff --git a/browser/components/extensions/test/browser/browser_ext_webRequest_error_after_stopped_or_closed.js b/browser/components/extensions/test/browser/browser_ext_webRequest_error_after_stopped_or_closed.js
index 75d85dd3bf..e14a498cd3 100644
--- a/browser/components/extensions/test/browser/browser_ext_webRequest_error_after_stopped_or_closed.js
+++ b/browser/components/extensions/test/browser/browser_ext_webRequest_error_after_stopped_or_closed.js
@@ -88,7 +88,7 @@ async function runTest(stopLoadFunc) {
  * our request.
  */
 add_task(async function test_click_stop_button() {
-  await runTest(async slowTab => {
+  await runTest(async () => {
     // Stop the load
     let stopButton = document.getElementById("stop-button");
     await TestUtils.waitForCondition(() => {
diff --git a/browser/components/extensions/test/browser/browser_ext_windows_create_tabId.js b/browser/components/extensions/test/browser/browser_ext_windows_create_tabId.js
index 83fda199b7..9b7aea478a 100644
--- a/browser/components/extensions/test/browser/browser_ext_windows_create_tabId.js
+++ b/browser/components/extensions/test/browser/browser_ext_windows_create_tabId.js
@@ -34,8 +34,7 @@ add_task(async function testWindowCreate() {
       return new Promise(resolve => {
         browser.tabs.onUpdated.addListener(function listener(
           tabId,
-          changeInfo,
-          tab
+          changeInfo
         ) {
           if (changeInfo.url === expected) {
             browser.tabs.onUpdated.removeListener(listener);
diff --git a/browser/components/extensions/test/browser/browser_ext_windows_update.js b/browser/components/extensions/test/browser/browser_ext_windows_update.js
index 7331b2c0cc..663f7a54d7 100644
--- a/browser/components/extensions/test/browser/browser_ext_windows_update.js
+++ b/browser/components/extensions/test/browser/browser_ext_windows_update.js
@@ -260,7 +260,7 @@ add_task(async function testPositionBoundaryCheck() {
   const extension = ExtensionTestUtils.loadExtension({
     async background() {
       function waitMessage() {
-        return new Promise((resolve, reject) => {
+        return new Promise(resolve => {
           const onMessage = message => {
             if (message == "continue") {
               browser.test.onMessage.removeListener(onMessage);
@@ -309,7 +309,7 @@ add_task(async function testPositionBoundaryCheck() {
     },
   });
 
-  const promisedWin = new Promise((resolve, reject) => {
+  const promisedWin = new Promise(resolve => {
     const windowListener = (window, topic) => {
       if (topic == "domwindowopened") {
         Services.ww.unregisterNotification(windowListener);
diff --git a/browser/components/extensions/test/browser/browser_unified_extensions_overflowable_toolbar.js b/browser/components/extensions/test/browser/browser_unified_extensions_overflowable_toolbar.js
index 9758a96636..2082bc29a9 100644
--- a/browser/components/extensions/test/browser/browser_unified_extensions_overflowable_toolbar.js
+++ b/browser/components/extensions/test/browser/browser_unified_extensions_overflowable_toolbar.js
@@ -217,7 +217,7 @@ async function withWindowOverflowed(
       return this._deferred.promise;
     },
 
-    onWidgetAdded(widgetID, area) {
+    onWidgetAdded(widgetID) {
       if (widgetID.endsWith("-browser-action")) {
         this._remainingBrowserActions--;
       }
@@ -263,7 +263,7 @@ async function withWindowOverflowed(
         return this._deferred.promise;
       },
 
-      onWidgetOverflow(widgetNode, areaNode) {
+      onWidgetOverflow() {
         this._remainingOverflowables--;
         if (!this._remainingOverflowables) {
           this._deferred.resolve();
@@ -489,7 +489,7 @@ add_task(async function test_context_menu() {
   let win = await BrowserTestUtils.openNewBrowserWindow();
 
   await withWindowOverflowed(win, {
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async (defaultList, unifiedExtensionList) => {
       Assert.ok(
         unifiedExtensionList.children.length,
         "Should have items in the Unified Extension list."
@@ -587,7 +587,7 @@ add_task(async function test_message_deck() {
   let win = await BrowserTestUtils.openNewBrowserWindow();
 
   await withWindowOverflowed(win, {
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async (defaultList, unifiedExtensionList) => {
       Assert.ok(
         unifiedExtensionList.children.length,
         "Should have items in the Unified Extension list."
@@ -825,7 +825,7 @@ add_task(async function test_pinning_to_toolbar_when_overflowed() {
         "expected no .toolbarbutton-1 CSS class on the menu button in the panel"
       );
     },
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async (defaultList, unifiedExtensionList) => {
       ok(
         actionButton.classList.contains("subviewbutton"),
         "expected .subviewbutton CSS class on the action button in the panel"
@@ -893,7 +893,7 @@ add_task(async function test_unpin_overflowed_widget() {
   let extensionID;
 
   await withWindowOverflowed(win, {
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async (defaultList, unifiedExtensionList) => {
       const firstExtensionWidget = unifiedExtensionList.children[0];
       Assert.ok(firstExtensionWidget, "expected an extension widget");
       extensionID = firstExtensionWidget.dataset.extensionid;
@@ -1120,7 +1120,7 @@ add_task(async function test_overflow_with_a_second_window() {
         "expected no .subviewbutton CSS class on the menu button in the second window"
       );
     },
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async () => {
       // The DOM node should have been overflowed.
       Assert.ok(
         aNode.hasAttribute("overflowedItem"),
@@ -1356,7 +1356,7 @@ add_task(async function test_overflowed_extension_cannot_be_moved() {
   let extensionID;
 
   await withWindowOverflowed(win, {
-    whenOverflowed: async (defaultList, unifiedExtensionList, extensionIDs) => {
+    whenOverflowed: async (defaultList, unifiedExtensionList) => {
       const secondExtensionWidget = unifiedExtensionList.children[1];
       Assert.ok(secondExtensionWidget, "expected an extension widget");
       extensionID = secondExtensionWidget.dataset.extensionid;
diff --git a/browser/components/extensions/test/browser/head.js b/browser/components/extensions/test/browser/head.js
index 02f905d05c..344eb3cca7 100644
--- a/browser/components/extensions/test/browser/head.js
+++ b/browser/components/extensions/test/browser/head.js
@@ -169,7 +169,7 @@ function promiseAnimationFrame(win = window) {
 
 function promisePopupHidden(popup) {
   return new Promise(resolve => {
-    let onPopupHidden = event => {
+    let onPopupHidden = () => {
       popup.removeEventListener("popuphidden", onPopupHidden);
       resolve();
     };
@@ -323,7 +323,7 @@ var awaitExtensionPanel = function (extension, win = window, awaitLoad = true) {
   return AppUiTestDelegate.awaitExtensionPanel(win, extension.id, awaitLoad);
 };
 
-function getCustomizableUIPanelID(win = window) {
+function getCustomizableUIPanelID() {
   return CustomizableUI.AREA_ADDONS;
 }
 
@@ -605,7 +605,7 @@ async function openChromeContextMenu(menuId, target, win = window) {
   return menu;
 }
 
-async function openSubmenu(submenuItem, win = window) {
+async function openSubmenu(submenuItem) {
   const submenu = submenuItem.menupopup;
   const shown = BrowserTestUtils.waitForEvent(submenu, "popupshown");
   submenuItem.openMenu(true);
@@ -763,7 +763,7 @@ function closePageAction(extension, win = window) {
 }
 
 function promisePrefChangeObserved(pref) {
-  return new Promise((resolve, reject) =>
+  return new Promise(resolve =>
     Preferences.observe(pref, function prefObserver() {
       Preferences.ignore(pref, prefObserver);
       resolve();
diff --git a/browser/components/extensions/test/browser/search-engines/search-config-v2.json b/browser/components/extensions/test/browser/search-engines/search-config-v2.json
new file mode 100644
index 0000000000..a696b26a75
--- /dev/null
+++ b/browser/components/extensions/test/browser/search-engines/search-config-v2.json
@@ -0,0 +1,97 @@
+{
+  "data": [
+    {
+      "recordType": "engine",
+      "identifier": "basic",
+      "base": {
+        "name": "basic",
+        "urls": {
+          "search": {
+            "base": "https://mochi.test:8888/browser/browser/components/search/test/browser/",
+            "params": [
+              {
+                "name": "foo",
+                "value": "1"
+              }
+            ],
+            "searchTermParamName": "search"
+          },
+          "suggestions": {
+            "base": "https://mochi.test:8888/browser/browser/modules/test/browser/usageTelemetrySearchSuggestions.sjs",
+            "searchTermParamName": "q"
+          }
+        }
+      },
+      "variants": [
+        {
+          "environment": { "allRegionsAndLocales": true }
+        }
+      ]
+    },
+    {
+      "recordType": "engine",
+      "identifier": "simple",
+      "base": {
+        "name": "Simple Engine",
+        "urls": {
+          "search": {
+            "base": "https://example.com",
+            "params": [
+              {
+                "name": "sourceId",
+                "value": "Mozilla-search"
+              }
+            ],
+            "searchTermParamName": "search"
+          },
+          "suggestions": {
+            "base": "https://example.com",
+            "searchTermParamName": "search"
+          }
+        }
+      },
+      "variants": [
+        {
+          "environment": { "allRegionsAndLocales": true }
+        }
+      ]
+    },
+    {
+      "recordType": "engine",
+      "identifier": "another",
+      "base": {
+        "name": "another",
+        "urls": {
+          "search": {
+            "base": "https://mochi.test:8888/browser/browser/components/search/test/browser/",
+            "params": [
+              {
+                "name": "bar",
+                "value": "1"
+              }
+            ],
+            "searchTermParamName": "search"
+          },
+          "suggestions": {
+            "base": "https://mochi.test:8888/browser/browser/modules/test/browser/usageTelemetrySearchSuggestions.sjs",
+            "searchTermParamName": "q"
+          }
+        }
+      },
+      "variants": [
+        {
+          "environment": { "allRegionsAndLocales": true }
+        }
+      ]
+    },
+    {
+      "recordType": "defaultEngines",
+      "globalDefault": "basic",
+      "specificDefaults": []
+    },
+    {
+      "recordType": "engineOrders",
+      "orders": []
+    }
+  ]
+}
diff --git a/browser/components/extensions/test/xpcshell/test_ext_browsingData_settings.js b/browser/components/extensions/test/xpcshell/test_ext_browsingData_settings.js
index 9d2241895c..843adfd0f1 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_browsingData_settings.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_browsingData_settings.js
@@ -18,7 +18,7 @@ const SETTINGS_LIST = [
 
 add_task(async function testSettingsProperties() {
   function background() {
-    browser.test.onMessage.addListener(msg => {
+    browser.test.onMessage.addListener(() => {
       browser.browsingData.settings().then(settings => {
         browser.test.sendMessage("settings", settings);
       });
@@ -108,7 +108,7 @@ add_task(async function testSettingsSince() {
   };
 
   function background() {
-    browser.test.onMessage.addListener(msg => {
+    browser.test.onMessage.addListener(() => {
       browser.browsingData.settings().then(settings => {
         browser.test.sendMessage("settings", settings);
       });
diff --git a/browser/components/extensions/test/xpcshell/test_ext_chrome_settings_overrides_update.js b/browser/components/extensions/test/xpcshell/test_ext_chrome_settings_overrides_update.js
index aac00a8023..b7b9deac0b 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_chrome_settings_overrides_update.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_chrome_settings_overrides_update.js
@@ -113,7 +113,7 @@ add_task(async function test_overrides_update_removal() {
   // that is the default, we do not prompt for default.
   let deferredPrompt = topicObservable(
     "webextension-defaultsearch-prompt",
-    (subject, message) => {
+    subject => {
       if (subject.wrappedJSObject.id == extension.id) {
         ok(false, "default override should not prompt");
       }
@@ -243,7 +243,7 @@ add_task(async function test_overrides_update_adding() {
 
   let deferredUpgradePrompt = topicObservable(
     "webextension-defaultsearch-prompt",
-    (subject, message) => {
+    subject => {
       if (subject.wrappedJSObject.id == extension.id) {
         ok(false, "should not prompt on update");
       }
@@ -351,7 +351,7 @@ async function withHandlingDefaultSearchPrompt({ extensionId, respond }, cb) {
   );
   const prompted = TestUtils.topicObserved(
     "webextension-defaultsearch-prompt",
-    (subject, message) => {
+    subject => {
       if (subject.wrappedJSObject.id == extensionId) {
         return subject.wrappedJSObject.respond(respond);
       }
@@ -364,7 +364,7 @@ async function withHandlingDefaultSearchPrompt({ extensionId, respond }, cb) {
 async function assertUpdateDoNotPrompt(extension, updateExtensionInfo) {
   let deferredUpgradePrompt = topicObservable(
     "webextension-defaultsearch-prompt",
-    (subject, message) => {
+    subject => {
       if (subject.wrappedJSObject.id == extension.id) {
         ok(false, "should not prompt on update");
       }
diff --git a/browser/components/extensions/test/xpcshell/test_ext_history.js b/browser/components/extensions/test/xpcshell/test_ext_history.js
index c0f6c39be7..0ad6893484 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_history.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_history.js
@@ -251,7 +251,7 @@ add_task(async function test_search() {
   function background(BGSCRIPT_REFERENCE_DATE) {
     const futureTime = Date.now() + 24 * 60 * 60 * 1000;
 
-    browser.test.onMessage.addListener(msg => {
+    browser.test.onMessage.addListener(() => {
       browser.history
         .search({ text: "" })
         .then(results => {
@@ -295,7 +295,7 @@ add_task(async function test_search() {
           });
         })
         .then(
-          results => {
+          () => {
             browser.test.fail(
               "history.search rejects with startTime that is after the endTime"
             );
diff --git a/browser/components/extensions/test/xpcshell/test_ext_homepage_overrides_private.js b/browser/components/extensions/test/xpcshell/test_ext_homepage_overrides_private.js
index 2d2bccc1e2..0fecc8c3e5 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_homepage_overrides_private.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_homepage_overrides_private.js
@@ -32,7 +32,7 @@ AddonTestUtils.overrideCertDB();
 createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "42");
 
 function promisePrefChange(pref) {
-  return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
     Services.prefs.addObserver(pref, function observer() {
       Services.prefs.removeObserver(pref, observer);
       resolve(arguments);
diff --git a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_defaults.js b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_defaults.js
index dd24be3aff..05ba807fae 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_defaults.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_defaults.js
@@ -23,6 +23,124 @@ const { sinon } = ChromeUtils.importESModule(
   "resource://testing-common/Sinon.sys.mjs"
 );
 
+const CONFIG_V2 = [
+  {
+    recordType: "engine",
+    identifier: "test",
+    base: {
+      name: "MozParamsTest",
+      urls: {
+        search: {
+          base: "https://example.com/",
+          params: [
+            {
+              name: "test-0",
+              searchAccessPoint: {
+                contextmenu: "0",
+              },
+            },
+            {
+              name: "test-1",
+              searchAccessPoint: {
+                searchbar: "1",
+              },
+            },
+            {
+              name: "test-2",
+              searchAccessPoint: {
+                homepage: "2",
+              },
+            },
+            {
+              name: "test-3",
+              searchAccessPoint: {
+                addressbar: "3",
+              },
+            },
+            {
+              name: "test-4",
+              searchAccessPoint: {
+                newtab: "4",
+              },
+            },
+            {
+              name: "simple",
+              value: "5",
+            },
+            {
+              name: "term",
+              value: "{searchTerms}",
+            },
+            {
+              name: "lang",
+              value: "{language}",
+            },
+            {
+              name: "locale",
+              value: "{moz:locale}",
+            },
+            {
+              name: "prefval",
+              experimentConfig: "code",
+            },
+            {
+              name: "experimenter-1",
+              experimentConfig: "nimbus-key-1",
+            },
+            {
+              name: "experimenter-2",
+              experimentConfig: "nimbus-key-2",
+            },
+          ],
+          searchTermParamName: "q",
+        },
+      },
+    },
+    variants: [
+      {
+        environment: {
+          allRegionsAndLocales: true,
+        },
+      },
+    ],
+  },
+  {
+    recordType: "engine",
+    identifier: "test2",
+    base: {
+      name: "MozParamsTest2",
+      urls: {
+        search: {
+          base: "https://example.com/2/",
+          params: [
+            {
+              name: "simple2",
+              value: "5",
+            },
+          ],
+          searchTermParamName: "q",
+        },
+      },
+    },
+    variants: [
+      {
+        environment: {
+          allRegionsAndLocales: true,
+        },
+      },
+    ],
+  },
+  {
+    recordType: "defaultEngines",
+    globalDefault: "test",
+    specificDefaults: [],
+  },
+  {
+    recordType: "engineOrders",
+    orders: [],
+  },
+];
+
 const URLTYPE_SUGGEST_JSON = "application/x-suggestions+json";
 
 AddonTestUtils.init(this);
@@ -43,29 +161,35 @@ add_task(async function setup() {
   AddonTestUtils.usePrivilegedSignatures = false;
   AddonTestUtils.overrideCertDB();
   await AddonTestUtils.promiseStartupManager();
-  await SearchTestUtils.useTestEngines("data", null, [
-    {
-      webExtension: {
-        id: "test@search.mozilla.org",
-      },
-      appliesTo: [
-        {
-          included: { everywhere: true },
-          default: "yes",
-        },
-      ],
-    },
-    {
-      webExtension: {
-        id: "test2@search.mozilla.org",
-      },
-      appliesTo: [
-        {
-          included: { everywhere: true },
-        },
-      ],
-    },
-  ]);
+  await SearchTestUtils.useTestEngines(
+    "data",
+    null,
+    SearchUtils.newSearchConfigEnabled
+      ? CONFIG_V2
+      : [
+          {
+            webExtension: {
+              id: "test@search.mozilla.org",
+            },
+            appliesTo: [
+              {
+                included: { everywhere: true },
+                default: "yes",
+              },
+            ],
+          },
+          {
+            webExtension: {
+              id: "test2@search.mozilla.org",
+            },
+            appliesTo: [
+              {
+                included: { everywhere: true },
+              },
+            ],
+          },
+        ]
+  );
   await Services.search.init();
   registerCleanupFunction(async () => {
     await AddonTestUtils.promiseShutdownManager();
@@ -124,7 +248,9 @@ add_task(async function test_extension_changing_to_app_provided_default() {
 
   assertEngineParameters({
     name: "MozParamsTest2",
-    searchURL: "https://example.com/2/?q={searchTerms}&simple2=5",
+    searchURL: SearchUtils.newSearchConfigEnabled
+      ? "https://example.com/2/?simple2=5&q={searchTerms}"
+      : "https://example.com/2/?q={searchTerms}&simple2=5",
     messageSnippet: "left unchanged",
   });
 
@@ -213,7 +339,9 @@ add_task(async function test_extension_overriding_app_provided_default() {
   );
   assertEngineParameters({
     name: "MozParamsTest2",
-    searchURL: "https://example.com/2/?q={searchTerms}&simple2=5",
+    searchURL: SearchUtils.newSearchConfigEnabled
+      ? "https://example.com/2/?simple2=5&q={searchTerms}"
+      : "https://example.com/2/?q={searchTerms}&simple2=5",
     messageSnippet: "reverted",
   });
 
@@ -256,7 +384,9 @@ add_task(async function test_extension_overriding_app_provided_default() {
 
   assertEngineParameters({
     name: "MozParamsTest2",
-    searchURL: "https://example.com/2/?q={searchTerms}&simple2=5",
+    searchURL: SearchUtils.newSearchConfigEnabled
+      ? "https://example.com/2/?simple2=5&q={searchTerms}"
+      : "https://example.com/2/?q={searchTerms}&simple2=5",
     messageSnippet: "reverted",
   });
   sinon.restore();
diff --git a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search.js b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search.js
index 10fed4d36b..e4e8fab79d 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search.js
@@ -60,19 +60,19 @@ add_task(async function test_extension_adding_engine() {
 
   let { baseURI } = ext1.extension;
   equal(
-    engine.getIconURL(),
+    await engine.getIconURL(),
     baseURI.resolve("foo.ico"),
     "16x16 icon path matches"
   );
   equal(
-    engine.getIconURL(16),
+    await engine.getIconURL(16),
     baseURI.resolve("foo.ico"),
     "16x16 icon path matches"
   );
   // TODO: Bug 1871036 - Differently sized icons are currently incorrectly
   // handled for add-ons.
   // equal(
-  //   engine.getIconURL(32),
+  //   await engine.getIconURL(32),
   //   baseURI.resolve("foo32.ico"),
   //   "32x32 icon path matches"
   // );
diff --git a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search_mozParam.js b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search_mozParam.js
index 3248c5cefa..5437d63d16 100644
--- a/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search_mozParam.js
+++ b/browser/components/extensions/test/xpcshell/test_ext_settings_overrides_search_mozParam.js
@@ -15,6 +15,9 @@ const { NimbusFeatures } = ChromeUtils.importESModule(
 const { sinon } = ChromeUtils.importESModule(
   "resource://testing-common/Sinon.sys.mjs"
 );
+const { SearchUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/SearchUtils.sys.mjs"
+);
 
 AddonTestUtils.init(this);
 AddonTestUtils.overrideCertDB();
@@ -51,23 +54,118 @@ const params = [
   { name: "prefval", condition: "pref", pref: "code" },
 ];
 
+const CONFIG = [
+  {
+    webExtension: {
+      id: "test@search.mozilla.org",
+    },
+    appliesTo: [
+      {
+        included: { everywhere: true },
+        default: "yes",
+      },
+    ],
+  },
+];
+const CONFIG_V2 = [
+  {
+    recordType: "engine",
+    identifier: "test",
+    base: {
+      name: "MozParamsTest",
+      urls: {
+        search: {
+          base: "https://example.com/",
+          params: [
+            {
+              name: "test-0",
+              searchAccessPoint: {
+                contextmenu: "0",
+              },
+            },
+            {
+              name: "test-1",
+              searchAccessPoint: {
+                searchbar: "1",
+              },
+            },
+            {
+              name: "test-2",
+              searchAccessPoint: {
+                homepage: "2",
+              },
+            },
+            {
+              name: "test-3",
+              searchAccessPoint: {
+                addressbar: "3",
+              },
+            },
+            {
+              name: "test-4",
+              searchAccessPoint: {
+                newtab: "4",
+              },
+            },
+            {
+              name: "simple",
+              value: "5",
+            },
+            {
+              name: "term",
+              value: "{searchTerms}",
+            },
+            {
+              name: "lang",
+              value: "{language}",
+            },
+            {
+              name: "locale",
+              value: "{moz:locale}",
+            },
+            {
+              name: "prefval",
+              experimentConfig: "code",
+            },
+            {
+              name: "experimenter-1",
+              experimentConfig: "nimbus-key-1",
+            },
+            {
+              name: "experimenter-2",
+              experimentConfig: "nimbus-key-2",
+            },
+          ],
+          searchTermParamName: "q",
+        },
+      },
+    },
+    variants: [
+      {
+        environment: { allRegionsAndLocales: true },
+      },
+    ],
+  },
+  {
+    recordType: "defaultEngines",
+    globalDefault: "test",
+    specificDefaults: [],
+  },
+  {
+    recordType: "engineOrders",
+    orders: [],
+  },
+];
+
 add_task(async function setup() {
   let readyStub = sinon.stub(NimbusFeatures.search, "ready").resolves();
   let updateStub = sinon.stub(NimbusFeatures.search, "onUpdate");
   await promiseStartupManager();
-  await SearchTestUtils.useTestEngines("data", null, [
-    {
-      webExtension: {
-        id: "test@search.mozilla.org",
-      },
-      appliesTo: [
-        {
-          included: { everywhere: true },
-          default: "yes",
-        },
-      ],
-    },
-  ]);
+  await SearchTestUtils.useTestEngines(
+    "data",
+    null,
+    SearchUtils.newSearchConfigEnabled ? CONFIG_V2 : CONFIG
+  );
   await Services.search.init();
   registerCleanupFunction(async () => {
     await promiseShutdownManager();
@@ -107,7 +205,9 @@ add_task(async function test_extension_setting_moz_params() {
     ).uri.spec;
     equal(
       expectedURL,
-      `https://example.com/?q=test&${p.name}=${p.value}&${paramStr}`,
+      SearchUtils.newSearchConfigEnabled
+        ? `https://example.com/?${p.name}=${p.value}&${paramStr}&q=test`
+        : `https://example.com/?q=test&${p.name}=${p.value}&${paramStr}`,
       "search url is expected"
     );
   }
@@ -180,7 +280,9 @@ add_task(async function test_nimbus_params() {
     ).uri.spec;
     equal(
       expectedURL,
-      `https://example.com/?q=test&${p.name}=${p.value}&${paramStr}`,
+      SearchUtils.newSearchConfigEnabled
+        ? `https://example.com/?${p.name}=${p.value}&${paramStr}&q=test`
+        : `https://example.com/?q=test&${p.name}=${p.value}&${paramStr}`,
       "search url is expected"
     );
   }