diff --git a/browser/components/asrouter/tests/browser/browser_asrouter_infobar.js b/browser/components/asrouter/tests/browser/browser_asrouter_infobar.js
index b80b3ec7a4b0..a01b2cf14c1f 100644
--- a/browser/components/asrouter/tests/browser/browser_asrouter_infobar.js
+++ b/browser/components/asrouter/tests/browser/browser_asrouter_infobar.js
@@ -107,7 +107,7 @@ add_task(async function react_to_trigger() {
     "Notification has default priority"
   );
   // Dismiss the notification
-  notificationStack.currentNotification.closeButtonEl.click();
+  notificationStack.currentNotification.closeButton.click();
 });
 
 add_task(async function dismiss_telemetry() {
@@ -128,7 +128,7 @@ add_task(async function dismiss_telemetry() {
   // Remove any IMPRESSION pings
   dispatchStub.reset();
 
-  infobar.notification.closeButtonEl.click();
+  infobar.notification.closeButton.click();
 
   await BrowserTestUtils.waitForCondition(
     () => infobar.notification === null,
@@ -204,7 +204,7 @@ add_task(async function prevent_multiple_messages() {
   Assert.equal(dispatchStub.callCount, 2, "Impression count did not increase");
 
   // Dismiss the first notification
-  infobar.notification.closeButtonEl.click();
+  infobar.notification.closeButton.click();
   Assert.equal(InfoBar._activeInfobar, null, "Cleared the active notification");
 
   // Reset impressions count
@@ -218,6 +218,6 @@ add_task(async function prevent_multiple_messages() {
   Assert.ok(InfoBar._activeInfobar, "activeInfobar is set");
   Assert.equal(dispatchStub.callCount, 2, "Called twice with IMPRESSION");
   // Dismiss the notification again
-  infobar.notification.closeButtonEl.click();
+  infobar.notification.closeButton.click();
   Assert.equal(InfoBar._activeInfobar, null, "Cleared the active notification");
 });
diff --git a/browser/modules/test/browser/browser_ProcessHangNotifications.js b/browser/modules/test/browser/browser_ProcessHangNotifications.js
index 9150c36d4c5a..963dc2d4b423 100644
--- a/browser/modules/test/browser/browser_ProcessHangNotifications.js
+++ b/browser/modules/test/browser/browser_ProcessHangNotifications.js
@@ -184,7 +184,7 @@ add_task(async function waitForScriptTest() {
   });
 
   // Click the "Close" button this time, we shouldn't get a callback at all.
-  notification.currentNotification.closeButtonEl.click();
+  notification.currentNotification.closeButton.click();
 
   // send another hang pulse, we should not get a notification here
   Services.obs.notifyObservers(hangReport, "process-hang-report");
diff --git a/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js b/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
index 6300bd17ba37..d105e8374e94 100644
--- a/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
+++ b/browser/modules/test/browser/browser_UnsubmittedCrashHandler.js
@@ -292,7 +292,7 @@ add_task(async function test_other_ignored() {
   Assert.ok(notification, "There should be a notification");
 
   // Dismiss notification, creating the .dmp.ignore file
-  notification.closeButtonEl.click();
+  notification.closeButton.click();
   gNotificationBox.removeNotification(notification, true);
   await waitForIgnoredReports(toIgnore);
 
@@ -525,7 +525,7 @@ add_task(async function test_can_ignore() {
   Assert.ok(notification, "There should be a notification");
 
   // Dismiss the notification by clicking on the "X" button.
-  notification.closeButtonEl.click();
+  notification.closeButton.click();
   // We'll not wait for the notification to finish its transition -
   // we'll just remove it right away.
   gNotificationBox.removeNotification(notification, true);
@@ -599,7 +599,7 @@ add_task(async function test_shutdown_while_not_showing() {
   Assert.ok(notification, "There should be a notification");
 
   // Dismiss the notification by clicking on the "X" button.
-  notification.closeButtonEl.click();
+  notification.closeButton.click();
   // We'll not wait for the notification to finish its transition -
   // we'll just remove it right away.
   gNotificationBox.removeNotification(notification, true);
diff --git a/testing/firefox-ui/tests/functional/safebrowsing/test_notification.py b/testing/firefox-ui/tests/functional/safebrowsing/test_notification.py
index d1110fc7d452..c8816a6e0fc4 100644
--- a/testing/firefox-ui/tests/functional/safebrowsing/test_notification.py
+++ b/testing/firefox-ui/tests/functional/safebrowsing/test_notification.py
@@ -123,7 +123,7 @@ class TestSafeBrowsingNotificationBar(WindowManagerMixin, MarionetteTestCase):
             message = notification_box.find_element(
                 By.CSS_SELECTOR, "notification-message[value=blocked-badware-page]"
             )
-            button = message.get_property("closeButtonEl")
+            button = message.get_property("closeButton")
             button.click()
 
             Wait(self.marionette, timeout=self.marionette.timeout.page_load).until(
diff --git a/toolkit/content/tests/widgets/test_moz_message_bar.html b/toolkit/content/tests/widgets/test_moz_message_bar.html
index 7ee6825ef355..5555ed5847c5 100644
--- a/toolkit/content/tests/widgets/test_moz_message_bar.html
+++ b/toolkit/content/tests/widgets/test_moz_message_bar.html
@@ -1,23 +1,25 @@
 <!DOCTYPE HTML>
 <html>
+
 <head>
   <meta charset="utf-8">
   <title>MozMessageBar tests</title>
   <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
   <script src="chrome://mochikit/content/tests/SimpleTest/EventUtils.js"></script>
-  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css"/>
+  <link rel="stylesheet" href="chrome://mochikit/content/tests/SimpleTest/test.css" />
   <script type="module" src="chrome://global/content/elements/moz-message-bar.mjs"></script>
 </head>
+
 <body>
-<p id="display"></p>
-<div id="content">
-  <moz-message-bar id="infoMessage" heading="Heading" message="Test message"></moz-message-bar>
-  <moz-message-bar id="infoMessage2" dismissable message="Test message"></moz-message-bar>
-  <moz-message-bar id="warningMessage" type="warning" message="Test message"></moz-message-bar>
-  <moz-message-bar id="successMessage" type="success" message="Test message"></moz-message-bar>
-  <moz-message-bar id="errorMessage" type="error" message="Test message"></moz-message-bar>
-</div>
-<pre id="test">
+  <p id="display"></p>
+  <div id="content">
+    <moz-message-bar id="infoMessage" heading="Heading" message="Test message"></moz-message-bar>
+    <moz-message-bar id="infoMessage2" dismissable message="Test message"></moz-message-bar>
+    <moz-message-bar id="warningMessage" type="warning" message="Test message"></moz-message-bar>
+    <moz-message-bar id="successMessage" type="success" message="Test message"></moz-message-bar>
+    <moz-message-bar id="errorMessage" type="error" message="Test message"></moz-message-bar>
+  </div>
+  <pre id="test">
   <script class="testbody" type="application/javascript">
     add_task(async function test_component_declaration() {
       const mozMessageBar = document.querySelector("#infoMessage");
@@ -48,11 +50,11 @@
 
     add_task(async function test_close_button() {
       const notDismissableComponent = document.querySelector("#infoMessage");
-      let closeButton = notDismissableComponent.closeButtonEl;
+      let closeButton = notDismissableComponent.closeButton;
       ok(!closeButton, "Close button doesn't show when the message bar isn't dismissable.");
 
       let dismissableComponent = document.querySelector("#infoMessage2");
-      closeButton = dismissableComponent.closeButtonEl;
+      closeButton = dismissableComponent.closeButton;
       ok(closeButton, "Close button is shown when the message bar is dismissable.");
 
       closeButton.click();
@@ -89,4 +91,5 @@
   </script>
 </pre>
 </body>
+
 </html>
diff --git a/toolkit/content/widgets/moz-message-bar/moz-message-bar.mjs b/toolkit/content/widgets/moz-message-bar/moz-message-bar.mjs
index 8f0c997149ab..d6258602b6a2 100644
--- a/toolkit/content/widgets/moz-message-bar/moz-message-bar.mjs
+++ b/toolkit/content/widgets/moz-message-bar/moz-message-bar.mjs
@@ -49,10 +49,10 @@ const messageTypeToIconData = {
 
 export default class MozMessageBar extends MozLitElement {
   static queries = {
-    actionsSlotEl: "slot[name=actions]",
+    actionsSlot: "slot[name=actions]",
     actionsEl: ".actions",
-    closeButtonEl: "moz-button.close",
-    supportLinkSlotEl: "slot[name=support-link]",
+    closeButton: "moz-button.close",
+    supportLinkSlot: "slot[name=support-link]",
   };
 
   static properties = {
@@ -72,7 +72,7 @@ export default class MozMessageBar extends MozLitElement {
   }
 
   onSlotchange() {
-    let actions = this.actionsSlotEl.assignedNodes();
+    let actions = this.actionsSlot.assignedNodes();
     this.actionsEl.classList.toggle("active", actions.length);
   }
 
@@ -87,7 +87,7 @@ export default class MozMessageBar extends MozLitElement {
   }
 
   get supportLinkEls() {
-    return this.supportLinkSlotEl.assignedElements();
+    return this.supportLinkSlot.assignedElements();
   }
 
   iconTemplate() {
diff --git a/toolkit/mozapps/extensions/test/browser/browser_html_discover_view.js b/toolkit/mozapps/extensions/test/browser/browser_html_discover_view.js
index 30cb45dc608e..47419ea71884 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_html_discover_view.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_html_discover_view.js
@@ -657,7 +657,7 @@ add_task(async function checkDiscopaneNotice() {
   messageBar = win.document.querySelector("moz-message-bar.discopane-notice");
   ok(messageBar, "Recommended notice should exist in disco view");
 
-  messageBar.closeButtonEl.click();
+  messageBar.closeButton.click();
   messageBar = win.document.querySelector("moz-message-bar.discopane-notice");
   ok(!messageBar, "Recommended notice should not exist in disco view");
   await switchToNonDiscoView(win);