diff --git a/core/.eslintignore b/core/.eslintignore
index 44777b9fe3..d06be16821 100644
--- a/core/.eslintignore
+++ b/core/.eslintignore
@@ -3,6 +3,7 @@ node_modules/**/*
 **/js_test_files/**/*
 *.js
 !*.es6.js
+modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.es6.js
 modules/locale/tests/locale_test.es6.js
 !tests/Drupal/Nightwatch/**/*.js
 misc/polyfills/array.find.es6.js
diff --git a/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.es6.js b/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.es6.js
new file mode 100644
index 0000000000..d131cf0f62
--- /dev/null
+++ b/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.es6.js
@@ -0,0 +1,34 @@
+(function (Drupal, once) {
+  Drupal.behaviors.CKEditor5Inspector = {
+    /**
+     * Facilitates adding and removing inspectors.
+     */
+    attach() {
+      // This is added in a Drupal behavior so it can be applied after the
+      // Drupal.CKEditor5Instances Map() is initialized without having to change
+      // loading weights.
+      once('ckeditor5-inspector', 'body').forEach(() => {
+        // Get the current set and delete functions from
+        // Drupal.CKEditor5Instances so they can be called in their overrides.
+        const oldSet = Drupal.CKEditor5Instances.set;
+        const oldDelete = Drupal.CKEditor5Instances.delete;
+
+        // Override set() so an inspector is added when it is called, then the
+        // default functionality is invoked.
+        Drupal.CKEditor5Instances.set = function (...args) {
+          const [id, editor] = args;
+          CKEditorInspector.attach({ [id]: editor });
+          return oldSet.apply(Drupal.CKEditor5Instances, args);
+        };
+
+        // Override delete() so an inspector is detached when it is called,
+        // then the default functionality is invoked.
+        Drupal.CKEditor5Instances.delete = function (...args) {
+          const [id] = args;
+          CKEditorInspector.detach(id);
+          return oldDelete.apply(Drupal.CKEditor5Instances, args);
+        };
+      });
+    },
+  };
+})(Drupal, once);
diff --git a/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.js b/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.js
index 02fdad4fe9..d86baa3251 100644
--- a/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.js
+++ b/core/modules/ckeditor5/modules/ckeditor5_dev/js/ckeditor5_dev.js
@@ -1,34 +1,40 @@
+/**
+* DO NOT EDIT THIS FILE.
+* See the following change record for more information,
+* https://www.drupal.org/node/2815083
+* @preserve
+**/
+
+function _defineProperty(obj, key, value) { if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+
 (function (Drupal, once) {
   Drupal.behaviors.CKEditor5Inspector = {
-    /**
-     * Facilitates adding and removing inspectors.
-     */
-    attach() {
-      // This is added in a Drupal behavior so it can be applied after the
-      // Drupal.CKEditor5Instances Map() is initialized without having to change
-      // loading weights.
-      once('ckeditor5-inspector', 'body').forEach(() => {
-        // Get the current set and delete functions from
-        // Drupal.CKEditor5Instances so they can be called in their overrides.
-        const oldSet = Drupal.CKEditor5Instances.set;
-        const oldDelete = Drupal.CKEditor5Instances.delete;
+    attach: function attach() {
+      once('ckeditor5-inspector', 'body').forEach(function () {
+        var oldSet = Drupal.CKEditor5Instances.set;
+        var oldDelete = Drupal.CKEditor5Instances.delete;
+
+        Drupal.CKEditor5Instances.set = function () {
+          for (var _len = arguments.length, args = new Array(_len), _key = 0; _key < _len; _key++) {
+            args[_key] = arguments[_key];
+          }
 
-        // Override set() so an inspector is added when it is called, then the
-        // default functionality is invoked.
-        Drupal.CKEditor5Instances.set = function (...args) {
-          const [id, editor] = args;
-          CKEditorInspector.attach( { [id]: editor } );
+          var id = args[0],
+              editor = args[1];
+          CKEditorInspector.attach(_defineProperty({}, id, editor));
           return oldSet.apply(Drupal.CKEditor5Instances, args);
         };
 
-        // Override delete() so an inspector is detached when it is called,
-        // then the default functionality is invoked.
-        Drupal.CKEditor5Instances.delete = function (...args) {
-          const [id] = args;
+        Drupal.CKEditor5Instances.delete = function () {
+          for (var _len2 = arguments.length, args = new Array(_len2), _key2 = 0; _key2 < _len2; _key2++) {
+            args[_key2] = arguments[_key2];
+          }
+
+          var id = args[0];
           CKEditorInspector.detach(id);
           return oldDelete.apply(Drupal.CKEditor5Instances, args);
-        }
+        };
       });
     }
-  }
-})(Drupal, once);
+  };
+})(Drupal, once);
\ No newline at end of file