diff --git a/browser/base/content/test/contextMenu/contextmenu_common.js b/browser/base/content/test/contextMenu/contextmenu_common.js
index 1fca51256c8d..766649429594 100644
--- a/browser/base/content/test/contextMenu/contextmenu_common.js
+++ b/browser/base/content/test/contextMenu/contextmenu_common.js
@@ -26,8 +26,8 @@ function openContextMenuFor(element, shiftkey, waitForSpellCheck) {
   }
 
   if (waitForSpellCheck) {
-    var { onSpellCheck } = SpecialPowers.ChromeUtils.import(
-      "resource://testing-common/AsyncSpellCheckTestHelper.jsm"
+    var { onSpellCheck } = SpecialPowers.ChromeUtils.importESModule(
+      "resource://testing-common/AsyncSpellCheckTestHelper.sys.mjs"
     );
     onSpellCheck(element, actuallyOpenContextMenuFor);
   } else {
@@ -364,8 +364,8 @@ async function test_contextmenu(selector, menuItems, options = {}) {
       gBrowser.selectedBrowser,
       [selector],
       async function(contentSelector) {
-        let { onSpellCheck } = ChromeUtils.import(
-          "resource://testing-common/AsyncSpellCheckTestHelper.jsm"
+        let { onSpellCheck } = ChromeUtils.importESModule(
+          "resource://testing-common/AsyncSpellCheckTestHelper.sys.mjs"
         );
         let element = content.document.querySelector(contentSelector);
         await new Promise(resolve => onSpellCheck(element, resolve));
diff --git a/editor/AsyncSpellCheckTestHelper.jsm b/editor/AsyncSpellCheckTestHelper.sys.mjs
similarity index 94%
rename from editor/AsyncSpellCheckTestHelper.jsm
rename to editor/AsyncSpellCheckTestHelper.sys.mjs
index 2b4b45684b07..6ceb2a86b205 100644
--- a/editor/AsyncSpellCheckTestHelper.jsm
+++ b/editor/AsyncSpellCheckTestHelper.sys.mjs
@@ -2,12 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-var EXPORTED_SYMBOLS = [
-  "maybeOnSpellCheck",
-  "onSpellCheck",
-  "getDictionaryContentPref",
-];
-
 const SPELL_CHECK_ENDED_TOPIC = "inlineSpellChecker-spellCheck-ended";
 const SPELL_CHECK_STARTED_TOPIC = "inlineSpellChecker-spellCheck-started";
 
@@ -32,7 +26,7 @@ const CP = Cc["@mozilla.org/content-pref/service;1"].getService(
  *                         of the event loop have passed to determine it has not
  *                         started.
  */
-function maybeOnSpellCheck(editableElement, callback) {
+export function maybeOnSpellCheck(editableElement, callback) {
   let editor = editableElement.editor;
   if (!editor) {
     let win = editableElement.ownerGlobal;
@@ -103,7 +97,7 @@ function maybeOnSpellCheck(editableElement, callback) {
  *                         of the event loop have passed to determine it has not
  *                         started.
  */
-function onSpellCheck(editableElement, callback) {
+export function onSpellCheck(editableElement, callback) {
   const { TestUtils } = ChromeUtils.importESModule(
     "resource://testing-common/TestUtils.sys.mjs"
   );
@@ -114,7 +108,7 @@ function onSpellCheck(editableElement, callback) {
   );
 }
 
-async function getDictionaryContentPref() {
+export async function getDictionaryContentPref() {
   let dictionaries = await new Promise(resolve => {
     let value = "";
     CP.getByDomainAndName("mochi.test", "spellcheck.lang", null, {
diff --git a/editor/moz.build b/editor/moz.build
index ffce2f43051c..5b526d4f1d93 100644
--- a/editor/moz.build
+++ b/editor/moz.build
@@ -27,7 +27,7 @@ XPIDL_SOURCES += [
 XPIDL_MODULE = "editor"
 
 TESTING_JS_MODULES += [
-    "AsyncSpellCheckTestHelper.jsm",
+    "AsyncSpellCheckTestHelper.sys.mjs",
 ]
 
 with Files("**"):
diff --git a/layout/tools/reftest/jar.mn b/layout/tools/reftest/jar.mn
index 298157d25227..4b76906575dc 100644
--- a/layout/tools/reftest/jar.mn
+++ b/layout/tools/reftest/jar.mn
@@ -51,7 +51,7 @@ reftest.jar:
   res/reftest-content.js (reftest-content.js)
   res/ReftestFissionParent.jsm (ReftestFissionParent.jsm)
   res/ReftestFissionChild.jsm (ReftestFissionChild.jsm)
-  res/AsyncSpellCheckTestHelper.jsm (../../../editor/AsyncSpellCheckTestHelper.jsm)
+  res/AsyncSpellCheckTestHelper.sys.mjs (../../../editor/AsyncSpellCheckTestHelper.sys.mjs)
   res/httpd.jsm (../../../netwerk/test/httpserver/httpd.js)
   res/StructuredLog.sys.mjs (../../../testing/modules/StructuredLog.sys.mjs)
   res/PerTestCoverageUtils.sys.mjs (../../../tools/code-coverage/PerTestCoverageUtils.sys.mjs)
diff --git a/layout/tools/reftest/reftest-content.js b/layout/tools/reftest/reftest-content.js
index aad7710ba7c2..d572ccc0bd71 100644
--- a/layout/tools/reftest/reftest-content.js
+++ b/layout/tools/reftest/reftest-content.js
@@ -18,8 +18,8 @@ const BLANK_URL_FOR_CLEARING = "data:text/html;charset=UTF-8,%3C%21%2D%2DCLEAR%2
 const { setTimeout, clearTimeout } = ChromeUtils.importESModule(
     "resource://gre/modules/Timer.sys.mjs"
 );
-const { onSpellCheck } = ChromeUtils.import(
-    "resource://reftest/AsyncSpellCheckTestHelper.jsm"
+const { onSpellCheck } = ChromeUtils.importESModule(
+    "resource://reftest/AsyncSpellCheckTestHelper.sys.mjs"
 );
 
 // This will load chrome Custom Elements inside chrome documents:
diff --git a/tools/esmify/map.json b/tools/esmify/map.json
index 421295b11fc4..f79032b01ef2 100644
--- a/tools/esmify/map.json
+++ b/tools/esmify/map.json
@@ -1798,6 +1798,8 @@
     "toolkit/components/pdfjs/content/build/pdf.sandbox.external.js",
   "resource://reftest/AsyncSpellCheckTestHelper.jsm":
     "editor/AsyncSpellCheckTestHelper.jsm",
+  "resource://testing-common/AsyncSpellCheckTestHelper.jsm":
+    "editor/AsyncSpellCheckTestHelper.jsm",
   "resource://reftest/PerTestCoverageUtils.jsm":
     "tools/code-coverage/PerTestCoverageUtils.jsm",
   "resource://reftest/ReftestFissionChild.jsm":