core/lib/Drupal/Core/Render/RendererInterface.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/lib/Drupal/Core/Render/RendererInterface.php b/core/lib/Drupal/Core/Render/RendererInterface.php
index 5ec6423..43f4f44 100644
--- a/core/lib/Drupal/Core/Render/RendererInterface.php
+++ b/core/lib/Drupal/Core/Render/RendererInterface.php
@@ -274,7 +274,7 @@ public function render(&$elements, $is_root_call = FALSE);
    *
    * Given a render array and its rendered output (HTML string), return an array
    * data structure that allows the render array and its associated metadata to
-   * be cached reliably.
+   * be cached reliably (and is serialization-safe).
    *
    * If Drupal needs additional rendering metadata to be cached at some point,
    * consumers of this method will continue to work. Those who only cache