diff --git a/core/lib/Drupal/Core/Config/ConfigBase.php b/core/lib/Drupal/Core/Config/ConfigBase.php
index 3e6b742..899d0de 100644
--- a/core/lib/Drupal/Core/Config/ConfigBase.php
+++ b/core/lib/Drupal/Core/Config/ConfigBase.php
@@ -158,7 +158,9 @@ public function get($key = '') {
    * @param array $data
    *   The new configuration data.
    * @param bool $validate_keys
-   *   Whether the data should be verified for valid keys.
+   *   Whether the data should be verified for valid keys. Set to FALSE if the
+   *   $data is known to be valid already (for example, being loaded from
+   *   the config storage).
    *
    * @return $this
    *   The configuration object.