Merging upstream version 126.0.

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

23 files changed, 54 insertions, 100 deletions

diff --git a/browser/components/customizableui/CustomizableUI.sys.mjs b/browser/components/customizableui/CustomizableUI.sys.mjs
index 5b09402dc1..9f9bbf37dc 100644
--- a/browser/components/customizableui/CustomizableUI.sys.mjs
+++ b/browser/components/customizableui/CustomizableUI.sys.mjs
@@ -1454,7 +1454,7 @@ var CustomizableUIInternal = {
     }
   },
 
-  onCustomizeEnd(aWindow) {
+  onCustomizeEnd() {
     this._clearPreviousUIState();
   },
 
@@ -6215,7 +6215,7 @@ class OverflowableToolbar {
    * nsIObserver implementation starts here.
    */
 
-  observe(aSubject, aTopic, aData) {
+  observe(aSubject, aTopic) {
     // This nsIObserver method allows us to defer initialization until after
     // this window has finished painting and starting up.
     if (
diff --git a/browser/components/customizableui/CustomizableWidgets.sys.mjs b/browser/components/customizableui/CustomizableWidgets.sys.mjs
index ab95e8e7db..1f37af7963 100644
--- a/browser/components/customizableui/CustomizableWidgets.sys.mjs
+++ b/browser/components/customizableui/CustomizableWidgets.sys.mjs
@@ -155,7 +155,7 @@ export const CustomizableWidgets = [
       panelview.panelMultiView.addEventListener("PanelMultiViewHidden", this);
       window.addEventListener("unload", this);
     },
-    onViewHiding(event) {
+    onViewHiding() {
       lazy.log.debug("History view is being hidden!");
     },
     onPanelMultiViewHidden(event) {
@@ -175,7 +175,7 @@ export const CustomizableWidgets = [
       }
       panelMultiView.removeEventListener("PanelMultiViewHidden", this);
     },
-    onWindowUnload(event) {
+    onWindowUnload() {
       if (this._panelMenuView) {
         delete this._panelMenuView;
       }
diff --git a/browser/components/customizableui/CustomizeMode.sys.mjs b/browser/components/customizableui/CustomizeMode.sys.mjs
index 5f6d01d833..7b4ee373be 100644
--- a/browser/components/customizableui/CustomizeMode.sys.mjs
+++ b/browser/components/customizableui/CustomizeMode.sys.mjs
@@ -28,7 +28,6 @@ ChromeUtils.defineESModuleGetters(lazy, {
   AddonManager: "resource://gre/modules/AddonManager.sys.mjs",
   BrowserUsageTelemetry: "resource:///modules/BrowserUsageTelemetry.sys.mjs",
   DragPositionManager: "resource:///modules/DragPositionManager.sys.mjs",
-  SessionStore: "resource:///modules/sessionstore/SessionStore.sys.mjs",
   URILoadingHelper: "resource:///modules/URILoadingHelper.sys.mjs",
 });
 ChromeUtils.defineLazyGetter(lazy, "gWidgetsBundle", function () {
@@ -63,14 +62,14 @@ var gTab;
 function closeGlobalTab() {
   let win = gTab.ownerGlobal;
   if (win.gBrowser.browsers.length == 1) {
-    win.BrowserOpenTab();
+    win.BrowserCommands.openTab();
   }
   win.gBrowser.removeTab(gTab, { animate: true });
   gTab = null;
 }
 
 var gTabsProgressListener = {
-  onLocationChange(aBrowser, aWebProgress, aRequest, aLocation, aFlags) {
+  onLocationChange(aBrowser, aWebProgress, aRequest, aLocation) {
     // Tear down customize mode when the customize mode tab loads some other page.
     // Customize mode will be re-entered if "about:blank" is loaded again, so
     // don't tear down in this case.
@@ -221,7 +220,6 @@ CustomizeMode.prototype = {
     gTab = aTab;
 
     gTab.setAttribute("customizemode", "true");
-    lazy.SessionStore.persistTabAttribute("customizemode");
 
     if (gTab.linkedPanel) {
       gTab.linkedBrowser.stop();
@@ -663,7 +661,7 @@ CustomizeMode.prototype = {
     });
   },
 
-  async addToToolbar(aNode, aReason) {
+  async addToToolbar(aNode) {
     aNode = this._getCustomizableChildForNode(aNode);
     if (aNode.localName == "toolbarpaletteitem" && aNode.firstElementChild) {
       aNode = aNode.firstElementChild;
@@ -1282,15 +1280,15 @@ CustomizeMode.prototype = {
     this._onUIChange();
   },
 
-  onWidgetMoved(aWidgetId, aArea, aOldPosition, aNewPosition) {
+  onWidgetMoved() {
     this._onUIChange();
   },
 
-  onWidgetAdded(aWidgetId, aArea, aPosition) {
+  onWidgetAdded() {
     this._onUIChange();
   },
 
-  onWidgetRemoved(aWidgetId, aArea) {
+  onWidgetRemoved() {
     this._onUIChange();
   },
 
@@ -1649,7 +1647,7 @@ CustomizeMode.prototype = {
     delete this.paletteDragHandler;
   },
 
-  observe(aSubject, aTopic, aData) {
+  observe(aSubject, aTopic) {
     switch (aTopic) {
       case "nsPref:changed":
         this._updateResetButton();
@@ -2329,7 +2327,7 @@ CustomizeMode.prototype = {
     }
   },
 
-  _setGridDragActive(aDragOverNode, aDraggedItem, aValue) {
+  _setGridDragActive(aDragOverNode, aDraggedItem) {
     let targetArea = this._getCustomizableParent(aDragOverNode);
     let draggedWrapper = this.$("wrapper-" + aDraggedItem.id);
     let originArea = this._getCustomizableParent(draggedWrapper);
@@ -2428,7 +2426,7 @@ CustomizeMode.prototype = {
     return aElement.closest(areas.map(a => "#" + CSS.escape(a)).join(","));
   },
 
-  _getDragOverNode(aEvent, aAreaElement, aAreaType, aDraggedItemId) {
+  _getDragOverNode(aEvent, aAreaElement, aAreaType) {
     let expectedParent =
       CustomizableUI.getCustomizationTarget(aAreaElement) || aAreaElement;
     if (!expectedParent.contains(aEvent.target)) {
diff --git a/browser/components/customizableui/content/panelUI.js b/browser/components/customizableui/content/panelUI.js
index f99560bd42..cb32085fd7 100644
--- a/browser/components/customizableui/content/panelUI.js
+++ b/browser/components/customizableui/content/panelUI.js
@@ -6,7 +6,6 @@ ChromeUtils.defineESModuleGetters(this, {
   AppMenuNotifications: "resource://gre/modules/AppMenuNotifications.sys.mjs",
   NewTabUtils: "resource://gre/modules/NewTabUtils.sys.mjs",
   PanelMultiView: "resource:///modules/PanelMultiView.sys.mjs",
-  ToolbarPanelHub: "resource:///modules/asrouter/ToolbarPanelHub.jsm",
 });
 
 /**
@@ -167,9 +166,6 @@ const PanelUI = {
     this.menuButton.removeEventListener("mousedown", this);
     this.menuButton.removeEventListener("keypress", this);
     CustomizableUI.removeListener(this);
-    if (this.whatsNewPanel) {
-      this.whatsNewPanel.removeEventListener("ViewShowing", this);
-    }
   },
 
   /**
@@ -303,11 +299,6 @@ const PanelUI = {
       case "activate":
         this.updateNotifications();
         break;
-      case "ViewShowing":
-        if (aEvent.target == this.whatsNewPanel) {
-          this.onWhatsNewPanelShowing();
-        }
-        break;
     }
   },
 
@@ -412,7 +403,6 @@ const PanelUI = {
       return;
     }
 
-    this.ensureWhatsNewInitialized(viewNode);
     this.ensurePanicViewInitialized(viewNode);
 
     let container = aAnchor.closest("panelmultiview");
@@ -497,24 +487,6 @@ const PanelUI = {
   },
 
   /**
-   * Sets up the event listener for when the What's New panel is shown.
-   *
-   * @param {panelview} panelView The What's New panelview.
-   */
-  ensureWhatsNewInitialized(panelView) {
-    if (panelView.id != "PanelUI-whatsNew" || panelView._initialized) {
-      return;
-    }
-
-    if (!this.whatsNewPanel) {
-      this.whatsNewPanel = panelView;
-    }
-
-    panelView._initialized = true;
-    panelView.addEventListener("ViewShowing", this);
-  },
-
-  /**
    * Adds FTL before appending the panic view markup to the main DOM.
    *
    * @param {panelview} panelView The Panic View panelview.
@@ -533,17 +505,6 @@ const PanelUI = {
   },
 
   /**
-   * When the What's New panel is showing, we fetch the messages to show.
-   */
-  onWhatsNewPanelShowing() {
-    ToolbarPanelHub.renderMessages(
-      window,
-      document,
-      "PanelUI-whatsNew-message-container"
-    );
-  },
-
-  /**
    * NB: The enable- and disableSingleSubviewPanelAnimations methods only
    * affect the hiding/showing animations of single-subview panels (tempPanel
    * in the showSubView method).
@@ -568,7 +529,7 @@ const PanelUI = {
     }
   },
 
-  onWidgetAfterDOMChange(aNode, aNextNode, aContainer, aWasRemoval) {
+  onWidgetAfterDOMChange(aNode, aNextNode, aContainer) {
     if (aContainer == this.overflowFixedList) {
       this.updateOverflowStatus();
     }
@@ -601,7 +562,7 @@ const PanelUI = {
     }
   },
 
-  _onHelpViewShow(aEvent) {
+  _onHelpViewShow() {
     // Call global menu setup function
     buildHelpMenu();
 
diff --git a/browser/components/customizableui/test/browser_1087303_button_fullscreen.js b/browser/components/customizableui/test/browser_1087303_button_fullscreen.js
index f67e81b892..42f9b58370 100644
--- a/browser/components/customizableui/test/browser_1087303_button_fullscreen.js
+++ b/browser/components/customizableui/test/browser_1087303_button_fullscreen.js
@@ -44,7 +44,7 @@ function promiseFullscreenChange() {
       reject("Fullscreen change did not happen within " + 20000 + "ms");
     }, 20000);
 
-    function onFullscreenChange(event) {
+    function onFullscreenChange() {
       clearTimeout(timeoutId);
       window.removeEventListener("fullscreen", onFullscreenChange, true);
       info("Fullscreen event received");
diff --git a/browser/components/customizableui/test/browser_1087303_button_preferences.js b/browser/components/customizableui/test/browser_1087303_button_preferences.js
index 7db48341cb..86bc89f48e 100644
--- a/browser/components/customizableui/test/browser_1087303_button_preferences.js
+++ b/browser/components/customizableui/test/browser_1087303_button_preferences.js
@@ -47,7 +47,7 @@ function waitForPageLoad(aTab) {
       reject("Page didn't load within " + 20000 + "ms");
     }, 20000);
 
-    async function onTabLoad(event) {
+    async function onTabLoad() {
       clearTimeout(timeoutId);
       aTab.linkedBrowser.removeEventListener("load", onTabLoad, true);
       info("Tab event received: load");
diff --git a/browser/components/customizableui/test/browser_1484275_PanelMultiView_toggle_with_other_popup.js b/browser/components/customizableui/test/browser_1484275_PanelMultiView_toggle_with_other_popup.js
index 89b86dba20..5d44cb1664 100644
--- a/browser/components/customizableui/test/browser_1484275_PanelMultiView_toggle_with_other_popup.js
+++ b/browser/components/customizableui/test/browser_1484275_PanelMultiView_toggle_with_other_popup.js
@@ -21,7 +21,7 @@ add_task(async function test_PanelMultiView_toggle_with_other_popup() {
       gBrowser,
       url: TEST_URL,
     },
-    async function (browser) {
+    async function () {
       // 1. Open the main menu.
       await gCUITestUtils.openMainMenu();
 
diff --git a/browser/components/customizableui/test/browser_885052_customize_mode_observers_disabed.js b/browser/components/customizableui/test/browser_885052_customize_mode_observers_disabed.js
index 346608dc99..b174d2bccf 100644
--- a/browser/components/customizableui/test/browser_885052_customize_mode_observers_disabed.js
+++ b/browser/components/customizableui/test/browser_885052_customize_mode_observers_disabed.js
@@ -34,7 +34,7 @@ add_task(async function () {
     "Should not be in fullscreen sizemode before we enter fullscreen."
   );
 
-  BrowserFullScreen();
+  BrowserCommands.fullScreen();
   await TestUtils.waitForCondition(() => isFullscreenSizeMode());
   ok(
     fullscreenButton.checked,
@@ -62,7 +62,7 @@ add_task(async function () {
 
   await endCustomizing();
 
-  BrowserFullScreen();
+  BrowserCommands.fullScreen();
   fullscreenButton = document.getElementById("fullscreen-button");
   await TestUtils.waitForCondition(() => !isFullscreenSizeMode());
   ok(
diff --git a/browser/components/customizableui/test/browser_940307_panel_click_closure_handling.js b/browser/components/customizableui/test/browser_940307_panel_click_closure_handling.js
index 0cf9a93341..8f2dc87e19 100644
--- a/browser/components/customizableui/test/browser_940307_panel_click_closure_handling.js
+++ b/browser/components/customizableui/test/browser_940307_panel_click_closure_handling.js
@@ -124,18 +124,17 @@ add_task(async function disabled_button_in_panel() {
   button.remove();
 });
 
-registerCleanupFunction(function () {
+registerCleanupFunction(async function () {
   if (button && button.parentNode) {
     button.remove();
   }
   if (menuButton && menuButton.parentNode) {
     menuButton.remove();
   }
-  // Sadly this isn't task.jsm-enabled, so we can't wait for this to happen. But we should
-  // definitely close it here and hope it won't interfere with other tests.
-  // Of course, all the tests are meant to do this themselves, but if they fail...
   if (isOverflowOpen()) {
+    let panelHiddenPromise = promiseOverflowHidden(window);
     PanelUI.overflowPanel.hidePopup();
+    await panelHiddenPromise;
   }
   CustomizableUI.reset();
 });
diff --git a/browser/components/customizableui/test/browser_947914_button_newPrivateWindow.js b/browser/components/customizableui/test/browser_947914_button_newPrivateWindow.js
index cc8842a3e8..42daab891f 100644
--- a/browser/components/customizableui/test/browser_947914_button_newPrivateWindow.js
+++ b/browser/components/customizableui/test/browser_947914_button_newPrivateWindow.js
@@ -21,7 +21,7 @@ add_task(async function () {
   let privateWindow = null;
 
   let observerWindowOpened = {
-    observe(aSubject, aTopic, aData) {
+    observe(aSubject, aTopic) {
       if (aTopic == "domwindowopened") {
         privateWindow = aSubject;
         privateWindow.addEventListener(
diff --git a/browser/components/customizableui/test/browser_947914_button_newWindow.js b/browser/components/customizableui/test/browser_947914_button_newWindow.js
index 591d13191e..910dd2a179 100644
--- a/browser/components/customizableui/test/browser_947914_button_newWindow.js
+++ b/browser/components/customizableui/test/browser_947914_button_newWindow.js
@@ -21,7 +21,7 @@ add_task(async function () {
   let newWindow = null;
 
   let observerWindowOpened = {
-    observe(aSubject, aTopic, aData) {
+    observe(aSubject, aTopic) {
       if (aTopic == "domwindowopened") {
         newWindow = aSubject;
         newWindow.addEventListener(
diff --git a/browser/components/customizableui/test/browser_947914_button_zoomReset.js b/browser/components/customizableui/test/browser_947914_button_zoomReset.js
index 7dc8299b28..c97e2f17d1 100644
--- a/browser/components/customizableui/test/browser_947914_button_zoomReset.js
+++ b/browser/components/customizableui/test/browser_947914_button_zoomReset.js
@@ -12,7 +12,7 @@ add_task(async function () {
 
   await BrowserTestUtils.withNewTab(
     { gBrowser, url: "http://example.com", waitForLoad: true },
-    async function (browser) {
+    async function () {
       CustomizableUI.addWidgetToArea(
         "zoom-controls",
         CustomizableUI.AREA_FIXED_OVERFLOW_PANEL
diff --git a/browser/components/customizableui/test/browser_972267_customizationchange_events.js b/browser/components/customizableui/test/browser_972267_customizationchange_events.js
index 7d27b94136..fdd7236d65 100644
--- a/browser/components/customizableui/test/browser_972267_customizationchange_events.js
+++ b/browser/components/customizableui/test/browser_972267_customizationchange_events.js
@@ -11,7 +11,7 @@ add_task(async function () {
   let otherToolbox = newWindow.gNavToolbox;
 
   let handlerCalledCount = 0;
-  let handler = ev => {
+  let handler = () => {
     handlerCalledCount++;
   };
 
diff --git a/browser/components/customizableui/test/browser_customization_context_menus.js b/browser/components/customizableui/test/browser_customization_context_menus.js
index 526b3abd1b..3f4c94fb72 100644
--- a/browser/components/customizableui/test/browser_customization_context_menus.js
+++ b/browser/components/customizableui/test/browser_customization_context_menus.js
@@ -171,8 +171,8 @@ add_task(async function urlbar_context() {
   let contextMenu = document.getElementById("toolbar-context-menu");
   let shownPromise = popupShown(contextMenu);
   let urlBarContainer = document.getElementById("urlbar-container");
-  // Need to make sure not to click within an edit field.
-  EventUtils.synthesizeMouse(urlBarContainer, 100, 1, {
+  // This clicks in the urlbar container margin, to avoid hitting the urlbar field.
+  EventUtils.synthesizeMouse(urlBarContainer, -2, 4, {
     type: "contextmenu",
     button: 2,
   });
@@ -549,7 +549,7 @@ add_task(async function custom_context_menus() {
   await startCustomizing();
   is(
     widget.getAttribute("context"),
-    "",
+    null,
     "Should not have own context menu in the toolbar now that we're customizing."
   );
   is(
@@ -562,7 +562,7 @@ add_task(async function custom_context_menus() {
   simulateItemDrag(widget, panel);
   is(
     widget.getAttribute("context"),
-    "",
+    null,
     "Should not have own context menu when in the panel."
   );
   is(
@@ -577,7 +577,7 @@ add_task(async function custom_context_menus() {
   );
   is(
     widget.getAttribute("context"),
-    "",
+    null,
     "Should not have own context menu when back in toolbar because we're still customizing."
   );
   is(
diff --git a/browser/components/customizableui/test/browser_editcontrols_update.js b/browser/components/customizableui/test/browser_editcontrols_update.js
index 9f064e521a..1276606779 100644
--- a/browser/components/customizableui/test/browser_editcontrols_update.js
+++ b/browser/components/customizableui/test/browser_editcontrols_update.js
@@ -29,7 +29,7 @@ function expectCommandUpdate(count, testWindow = window) {
       supportsCommand(cmd) {
         return cmd == "cmd_delete";
       },
-      isCommandEnabled(cmd) {
+      isCommandEnabled() {
         if (!count) {
           ok(false, "unexpected update");
           reject();
diff --git a/browser/components/customizableui/test/browser_open_in_lazy_tab.js b/browser/components/customizableui/test/browser_open_in_lazy_tab.js
index c18de67698..696bfde69b 100644
--- a/browser/components/customizableui/test/browser_open_in_lazy_tab.js
+++ b/browser/components/customizableui/test/browser_open_in_lazy_tab.js
@@ -9,7 +9,7 @@ add_task(async function open_customize_mode_in_lazy_tab() {
   });
   gCustomizeMode.setTab(tab);
 
-  is(tab.linkedPanel, "", "Tab should be lazy");
+  is(tab.linkedPanel, null, "Tab should be lazy");
 
   let title = gNavigatorBundle.getFormattedString("customizeMode.tabTitle", [
     document.getElementById("bundle_brand").getString("brandShortName"),
diff --git a/browser/components/customizableui/test/browser_panelUINotifications.js b/browser/components/customizableui/test/browser_panelUINotifications.js
index 818fcbad39..d5f2cc0450 100644
--- a/browser/components/customizableui/test/browser_panelUINotifications.js
+++ b/browser/components/customizableui/test/browser_panelUINotifications.js
@@ -14,7 +14,7 @@ add_task(async function testMainActionCalled() {
     url: "about:blank",
   };
 
-  await BrowserTestUtils.withNewTab(options, function (browser) {
+  await BrowserTestUtils.withNewTab(options, function () {
     is(
       PanelUI.notificationPanel.state,
       "closed",
@@ -77,7 +77,7 @@ add_task(async function testSecondaryActionWorkflow() {
     url: "about:blank",
   };
 
-  await BrowserTestUtils.withNewTab(options, async function (browser) {
+  await BrowserTestUtils.withNewTab(options, async function () {
     is(
       PanelUI.notificationPanel.state,
       "closed",
@@ -167,7 +167,7 @@ add_task(async function testDownloadingBadge() {
     url: "about:blank",
   };
 
-  await BrowserTestUtils.withNewTab(options, async function (browser) {
+  await BrowserTestUtils.withNewTab(options, async function () {
     let mainActionCalled = false;
     let mainAction = {
       callback: () => {
@@ -225,7 +225,7 @@ add_task(async function testDownloadingBadge() {
  *   then we display any other badges that are remaining.
  */
 add_task(async function testInteractionWithBadges() {
-  await BrowserTestUtils.withNewTab("about:blank", async function (browser) {
+  await BrowserTestUtils.withNewTab("about:blank", async function () {
     // Remove the fxa toolbar button from the navbar to ensure the notification
     // is displayed on the app menu button.
     let { CustomizableUI } = ChromeUtils.importESModule(
@@ -328,7 +328,7 @@ add_task(async function testInteractionWithBadges() {
  * This tests that adding a badge will not dismiss any existing doorhangers.
  */
 add_task(async function testAddingBadgeWhileDoorhangerIsShowing() {
-  await BrowserTestUtils.withNewTab("about:blank", function (browser) {
+  await BrowserTestUtils.withNewTab("about:blank", function () {
     is(
       PanelUI.notificationPanel.state,
       "closed",
@@ -468,7 +468,7 @@ add_task(async function testMultipleBadges() {
  * Tests that non-badges also operate like a stack.
  */
 add_task(async function testMultipleNonBadges() {
-  await BrowserTestUtils.withNewTab("about:blank", async function (browser) {
+  await BrowserTestUtils.withNewTab("about:blank", async function () {
     is(
       PanelUI.notificationPanel.state,
       "closed",
diff --git a/browser/components/customizableui/test/browser_panelUINotifications_fullscreen_noAutoHideToolbar.js b/browser/components/customizableui/test/browser_panelUINotifications_fullscreen_noAutoHideToolbar.js
index 853c39e89f..d90f928ed9 100644
--- a/browser/components/customizableui/test/browser_panelUINotifications_fullscreen_noAutoHideToolbar.js
+++ b/browser/components/customizableui/test/browser_panelUINotifications_fullscreen_noAutoHideToolbar.js
@@ -20,7 +20,7 @@ function waitForDocshellActivated() {
       content.document,
       "visibilitychange",
       true /* capture */,
-      aEvent => {
+      () => {
         return content.browsingContext.isActive;
       }
     );
diff --git a/browser/components/customizableui/test/browser_panelUINotifications_modals.js b/browser/components/customizableui/test/browser_panelUINotifications_modals.js
index 87be14fcee..a3aa6d058a 100644
--- a/browser/components/customizableui/test/browser_panelUINotifications_modals.js
+++ b/browser/components/customizableui/test/browser_panelUINotifications_modals.js
@@ -8,10 +8,6 @@ const { AppMenuNotifications } = ChromeUtils.importESModule(
 );
 
 add_task(async function testModals() {
-  await SpecialPowers.pushPrefEnv({
-    set: [["prompts.windowPromptSubDialog", true]],
-  });
-
   is(
     PanelUI.notificationPanel.state,
     "closed",
diff --git a/browser/components/customizableui/test/browser_panelUINotifications_multiWindow.js b/browser/components/customizableui/test/browser_panelUINotifications_multiWindow.js
index fd75763857..edda165692 100644
--- a/browser/components/customizableui/test/browser_panelUINotifications_multiWindow.js
+++ b/browser/components/customizableui/test/browser_panelUINotifications_multiWindow.js
@@ -15,7 +15,7 @@ add_task(async function testDoesNotShowDoorhangerForBackgroundWindow() {
     url: "about:blank",
   };
 
-  await BrowserTestUtils.withNewTab(options, async function (browser) {
+  await BrowserTestUtils.withNewTab(options, async function () {
     let win = await BrowserTestUtils.openNewBrowserWindow();
     await SimpleTest.promiseFocus(win);
     let mainActionCalled = false;
@@ -95,7 +95,7 @@ add_task(
       url: "about:blank",
     };
 
-    await BrowserTestUtils.withNewTab(options, async function (browser) {
+    await BrowserTestUtils.withNewTab(options, async function () {
       let win = await BrowserTestUtils.openNewBrowserWindow();
       await SimpleTest.promiseFocus(win);
       AppMenuNotifications.showNotification("update-manual", { callback() {} });
@@ -140,7 +140,7 @@ add_task(
       url: "about:blank",
     };
 
-    await BrowserTestUtils.withNewTab(options, async function (browser) {
+    await BrowserTestUtils.withNewTab(options, async function () {
       let win = await BrowserTestUtils.openNewBrowserWindow();
       await SimpleTest.promiseFocus(win);
       AppMenuNotifications.showNotification("update-manual", { callback() {} });
diff --git a/browser/components/customizableui/test/browser_switch_to_customize_mode.js b/browser/components/customizableui/test/browser_switch_to_customize_mode.js
index 55e80d3517..e3988cb41e 100644
--- a/browser/components/customizableui/test/browser_switch_to_customize_mode.js
+++ b/browser/components/customizableui/test/browser_switch_to_customize_mode.js
@@ -18,7 +18,7 @@ add_task(async function () {
   await finishedCustomizing;
 
   let startedCount = 0;
-  let handler = e => startedCount++;
+  let handler = () => startedCount++;
   gNavToolbox.addEventListener("customizationstarting", handler);
   await startCustomizing();
   CustomizableUI.removeWidgetFromArea("stop-reload-button");
diff --git a/browser/components/customizableui/test/browser_synced_tabs_menu.js b/browser/components/customizableui/test/browser_synced_tabs_menu.js
index ff60167fea..33c8f6a845 100644
--- a/browser/components/customizableui/test/browser_synced_tabs_menu.js
+++ b/browser/components/customizableui/test/browser_synced_tabs_menu.js
@@ -40,7 +40,7 @@ function updateTabsPanel() {
   return promiseTabsUpdated;
 }
 
-// This is the mock we use for SyncedTabs.jsm - tests may override various
+// This is the mock we use for SyncedTabs.sys.mjs - tests may override various
 // functions.
 let mockedInternal = {
   get isConfiguredToSyncTabs() {
@@ -378,7 +378,7 @@ add_task(async function () {
   // There is a single node saying there's no tabs for the client.
   node = node.nextElementSibling;
   is(node.nodeName, "label", "node is a label");
-  is(node.getAttribute("itemtype"), "", "node is neither a tab nor a client");
+  is(node.getAttribute("itemtype"), null, "node is neither a tab nor a client");
 
   node = node.nextElementSibling;
   is(node, null, "no more siblings");
@@ -514,7 +514,7 @@ add_task(async function () {
     return promise;
   }
 
-  showMoreButton = checkTabsPage(25, "Show More Tabs");
+  showMoreButton = checkTabsPage(25, "Show more tabs");
   await clickShowMoreButton();
 
   checkTabsPage(77, null);
diff --git a/browser/components/customizableui/test/head.js b/browser/components/customizableui/test/head.js
index f8c0d02a12..bc1e88ed61 100644
--- a/browser/components/customizableui/test/head.js
+++ b/browser/components/customizableui/test/head.js
@@ -267,7 +267,7 @@ function openAndLoadWindow(aOptions, aWaitForDelayedStartup = false) {
   return new Promise(resolve => {
     let win = OpenBrowserWindow(aOptions);
     if (aWaitForDelayedStartup) {
-      Services.obs.addObserver(function onDS(aSubject, aTopic, aData) {
+      Services.obs.addObserver(function onDS(aSubject) {
         if (aSubject != win) {
           return;
         }
@@ -309,7 +309,7 @@ function promisePanelElementShown(win, aPanel) {
     let timeoutId = win.setTimeout(() => {
       reject("Panel did not show within 20 seconds.");
     }, 20000);
-    function onPanelOpen(e) {
+    function onPanelOpen() {
       aPanel.removeEventListener("popupshown", onPanelOpen);
       win.clearTimeout(timeoutId);
       resolve();
@@ -328,7 +328,7 @@ function promisePanelElementHidden(win, aPanel) {
     let timeoutId = win.setTimeout(() => {
       reject("Panel did not hide within 20 seconds.");
     }, 20000);
-    function onPanelClose(e) {
+    function onPanelClose() {
       aPanel.removeEventListener("popuphidden", onPanelClose);
       win.clearTimeout(timeoutId);
       executeSoon(resolve);
@@ -352,7 +352,7 @@ function subviewShown(aSubview) {
     let timeoutId = win.setTimeout(() => {
       reject("Subview (" + aSubview.id + ") did not show within 20 seconds.");
     }, 20000);
-    function onViewShown(e) {
+    function onViewShown() {
       aSubview.removeEventListener("ViewShown", onViewShown);
       win.clearTimeout(timeoutId);
       resolve();
@@ -367,7 +367,7 @@ function subviewHidden(aSubview) {
     let timeoutId = win.setTimeout(() => {
       reject("Subview (" + aSubview.id + ") did not hide within 20 seconds.");
     }, 20000);
-    function onViewHiding(e) {
+    function onViewHiding() {
       aSubview.removeEventListener("ViewHiding", onViewHiding);
       win.clearTimeout(timeoutId);
       resolve();
@@ -406,7 +406,7 @@ function promiseTabLoadEvent(aTab, aURL) {
  * @return {Promise} resolved when the requisite mutation shows up.
  */
 function promiseAttributeMutation(aNode, aAttribute, aFilterFn) {
-  return new Promise((resolve, reject) => {
+  return new Promise(resolve => {
     info("waiting for mutation of attribute '" + aAttribute + "'.");
     let obs = new MutationObserver(mutations => {
       for (let mut of mutations) {