diff --git a/core/lib/Drupal/Core/Theme/ThemeInitialization.php b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
index 8b476a2..f9849c7 100644
--- a/core/lib/Drupal/Core/Theme/ThemeInitialization.php
+++ b/core/lib/Drupal/Core/Theme/ThemeInitialization.php
@@ -160,6 +160,7 @@ public function getActiveTheme(Extension $theme, array $base_themes = []) {
 
     $values['path'] = $theme_path;
     $values['name'] = $theme->getName();
+    $values['status'] = $values['name'] != 'core';
 
     // Prepare stylesheets from this theme as well as all ancestor themes.
     // We work it this way so that we can have child themes remove CSS files