diff -u b/core/lib/Drupal/Core/Utility/ThemeRegistry.php b/core/lib/Drupal/Core/Utility/ThemeRegistry.php
--- b/core/lib/Drupal/Core/Utility/ThemeRegistry.php
+++ b/core/lib/Drupal/Core/Utility/ThemeRegistry.php
@@ -62,7 +62,7 @@
    * @param \Drupal\Core\Lock\LockBackendInterface $lock
    *   The lock backend.
    * @param \Drupal\Core\Theme\ActiveTheme $theme
-   *   The theme object representing the active theme for this registry. 
+   *   The theme object representing the active theme for this registry.
    * @param array $tags
    *   (optional) The tags to specify for the cache item.
    * @param bool $modules_loaded