Bug 1983869 - Fix 'extensions settings' link click handling in post-install popup to preventing it to break customize mode. a=dmeehan

Original Revision: https://phabricator.services.mozilla.com/D264085

Differential Revision: https://phabricator.services.mozilla.com/D264286

browser/base/content/browser-addons.js

@@ -852,6 +852,13 @@ customElements.define(
             BrowserAddonUI.openAddonsMgr(
               "addons://detail/" + encodeURIComponent(addonId)
             );
+            // The settings link element has its href set to "#" to be
+            // accessible with keyboard navigation, and so we call
+            // preventDefault to avoid the "#" href to be implicitly
+            // added to the browser chrome window url (See Bug 1983869
+            // for more details of the regression that the implicit
+            // change to the chrome window urls triggers).
+            event.preventDefault();
           }
           break;
         }

toolkit/mozapps/extensions/test/browser/browser_permission_prompt.js

@@ -1617,6 +1617,15 @@ add_task(async function testVerifyPostInstallPopupWithDataCollection() {
         `addons://detail/${encodeURIComponent(extensionId)}`,
         "Expected about:addons to show the detail view of the extension"
       );
+
+      // Asserting the browser chrome window url to guard against regressions
+      // like Bug 1983869.
+      Assert.equal(
+        AppConstants.BROWSER_CHROME_URL,
+        tab.ownerGlobal.window.location.href,
+        "Expect browser chrome window url to be unchanged"
+      );
+
       BrowserTestUtils.removeTab(tab);
 
       // Dismiss the popup by clicking "OK".