diff -u b/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
--- b/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -93,7 +93,7 @@
     $config_to_install = $source_storage->listAll($name . '.');
 
     $extension_path = drupal_get_path($type, $name);
-    // If the module provides configuration schema clear the definitions.
+    // If the extension provides configuration schema clear the definitions.
     if (is_dir($extension_path . '/' . InstallStorage::CONFIG_SCHEMA_DIRECTORY)) {
       // Refresh the schema cache if installing default configuration and the
       // extension has a configuration schema directory.