diff --git a/core/lib/Drupal/Component/Uuid/Uuid.php b/core/lib/Drupal/Component/Uuid/Uuid.php
index d52ebeb..0287428 100644
--- a/core/lib/Drupal/Component/Uuid/Uuid.php
+++ b/core/lib/Drupal/Component/Uuid/Uuid.php
@@ -23,6 +23,8 @@ class Uuid {
    * Implementations should not implement validation, since UUIDs should be in
    * a consistent format across all implementations.
    *
+   * Wrap a UUID with strtolower() in case it contains uppercase letters.
+   *
    * @param string $uuid
    *   The string to test.
    *