diff --git a/core/lib/Drupal/Core/Entity/EntityTypeBundleInfo.php b/core/lib/Drupal/Core/Entity/EntityTypeBundleInfo.php
index 42d00a7..e454eee 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeBundleInfo.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeBundleInfo.php
@@ -19,7 +19,9 @@ class EntityTypeBundleInfo implements EntityTypeBundleInfoInterface {
   /**
    * Static cache of bundle information.
    *
-   * @var array
+   * @var array[]
+   *   The array has the same structure as the return value of
+   *   \Drupal\Core\Entity\EntityTypeBundleInfoInterface::getAllBundleInfo().
    */
   protected $bundleInfo;