--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -3,29 +3,28 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 @namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
 @namespace html url("http://www.w3.org/1999/xhtml");
 
 :root {
   --panelui-subview-transition-duration: 150ms;
   --lwt-additional-images: none;
+  --lwt-background-alignment: right top;
   --lwt-background-tiling: no-repeat;
 }
 
 :root:-moz-lwtheme {
+  background-color: var(--lwt-accent-color) !important;
   color: var(--lwt-text-color) !important;
 }
 
-:root:-moz-lwtheme {
-  background-color: var(--lwt-accent-color) !important;
-}
-
 :root:-moz-lwtheme[lwtheme-image] {
   background-image: var(--lwt-header-image) !important;
+  background-repeat: no-repeat;
   background-position: right top !important;
 }
 
 :root:-moz-lwtheme:-moz-window-inactive {
   background-color: var(--lwt-accent-color-inactive, var(--lwt-accent-color)) !important;
 }
 
 /* Set additional backgrounds alignment relative to toolbox */
@@ -495,21 +494,16 @@ toolbar:not(#TabsToolbar) > #personal-bo
 #appMenu_historyMenu > .bookmark-item,
 #appMenu-library-recentlyClosedTabs > .panel-subview-body > .bookmark-item,
 #appMenu-library-recentlyClosedWindows > .panel-subview-body > .bookmark-item,
 #appMenu-library-recentHighlights > .bookmark-item,
 #panelMenu_bookmarksMenu > .bookmark-item {
   max-width: none;
 }
 
-#main-window:-moz-lwtheme {
-  background-repeat: no-repeat;
-  background-position: top right;
-}
-
 %ifdef XP_MACOSX
 #main-window[inFullscreen="true"] {
   padding-top: 0; /* override drawintitlebar="true" */
 }
 %endif
 
 :root[lwthemefooter=true] #browser-bottombox:-moz-lwtheme {
   background-repeat: no-repeat;

--- a/toolkit/components/extensions/WebExtensionPolicy.cpp
+++ b/toolkit/components/extensions/WebExtensionPolicy.cpp
@@ -144,17 +144,17 @@ WebExtensionPolicy::WebExtensionPolicy(G
   , mPermissions(new AtomSet(aInit.mPermissions))
 {
   if (!ParseGlobs(aGlobal, aInit.mWebAccessibleResources, mWebAccessiblePaths,
                   aRv)) {
     return;
   }
 
   MatchPatternOptions options;
-  options.mRestrictSchemes = HasPermission(nsGkAtoms::mozillaAddons);
+  options.mRestrictSchemes = !HasPermission(nsGkAtoms::mozillaAddons);
 
   mHostPermissions = ParseMatches(aGlobal, aInit.mAllowedOrigins, options,
                                   ErrorBehavior::CreateEmptyPattern, aRv);
   if (aRv.Failed()) {
     return;
   }
 
   if (!aInit.mBackgroundScripts.IsNull()) {

--- a/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js
+++ b/toolkit/components/extensions/test/browser/browser_ext_themes_additional_backgrounds_alignment.js
@@ -1,16 +1,15 @@
 "use strict";
 
 /* globals InspectorUtils */
 
 // Case 1 - When there is a headerURL image and additional_backgrounds_alignment is not specified.
-// So background-position should default to "left top"
+// So background-position should default to "right top"
 add_task(async function test_default_additional_backgrounds_alignment() {
-  const LEFT_TOP = "0% 0%";
   const RIGHT_TOP = "100% 0%";
 
   let extension = ExtensionTestUtils.loadExtension({
     manifest: {
       "theme": {
         "images": {
           "headerURL": "image1.png",
           "additional_backgrounds": ["image1.png", "image1.png"],
@@ -39,17 +38,17 @@ add_task(async function test_default_add
   );
 
 
   let toolbox = document.querySelector("#navigator-toolbox");
   let toolboxCS = window.getComputedStyle(toolbox);
 
   Assert.equal(
     toolboxCS.getPropertyValue("background-position"),
-    LEFT_TOP,
+    RIGHT_TOP,
     toolbox.id + " only contains default additional backgrounds alignment property"
   );
 
   await extension.unload();
 });
 
 
 // Case 2 - When there is a headerURL image and additional_backgrounds_alignment is specified.

--- a/toolkit/components/extensions/test/browser/browser_ext_themes_multiple_backgrounds.js
+++ b/toolkit/components/extensions/test/browser/browser_ext_themes_multiple_backgrounds.js
@@ -97,17 +97,17 @@ add_task(async function test_support_bac
   let toolboxCS = window.getComputedStyle(toolbox);
   let bgImage = rootCS.backgroundImage.split(",")[0].trim();
   Assert.ok(bgImage.includes("face0.png"),
             `The backgroundImage should use face.png. Actual value is: ${bgImage}`);
   Assert.equal([1, 2, 3].map(num => bgImage.replace(/face[\d]*/, `face${num}`)).join(", "),
                toolboxCS.backgroundImage, "The backgroundImage should use face.png three times.");
   Assert.equal(rootCS.backgroundPosition, "100% 0%",
                "The backgroundPosition should use the default value for root.");
-  Assert.equal(toolboxCS.backgroundPosition, "0% 0%",
+  Assert.equal(toolboxCS.backgroundPosition, "100% 0%",
                "The backgroundPosition should use the default value for navigator-toolbox.");
   Assert.equal(rootCS.backgroundRepeat, "no-repeat",
                "The backgroundRepeat should use the default values for root.");
   Assert.equal(toolboxCS.backgroundRepeat, "repeat-x, repeat-y, repeat",
                "The backgroundRepeat should use the three values provided for navigator-toolbox.");
 
   await extension.unload();