diff --git a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
index 5ad4015..f2dcc5a 100644
--- a/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
+++ b/core/modules/ckeditor/src/Tests/CKEditorLoadingTest.php
@@ -206,7 +206,7 @@ function testExternalStylesheets() {
     ];
     $this->assertIdentical($expected, _ckeditor_theme_css('test_ckeditor_stylesheets_external'));
 
-    // Case 2: Install theme which has an external root-relative CSS URL.
+    // Case 2: Install theme which has an external protocol-relative CSS URL.
     \Drupal::service('theme_handler')->install(['test_ckeditor_stylesheets_external_root_relative']);
     \Drupal::service('theme_handler')->setDefault('test_ckeditor_stylesheets_external_root_relative');
     $expected = [