diff -u b/core/lib/Drupal/Core/Render/Element/Hidden.php b/core/lib/Drupal/Core/Render/Element/Hidden.php
--- b/core/lib/Drupal/Core/Render/Element/Hidden.php
+++ b/core/lib/Drupal/Core/Render/Element/Hidden.php
@@ -13,7 +13,6 @@
  * Provides a form element for an HTML 'hidden' input element.
  *
  * Properties:
- * - #value: The value of the form element that cannot be edited by the user.
  * - #default_value:  The initial value of the form element. JavaScript may be
  *   used to alter the value prior to submission.
  *
diff -u b/core/lib/Drupal/Core/Render/Element/Value.php b/core/lib/Drupal/Core/Render/Element/Value.php
--- b/core/lib/Drupal/Core/Render/Element/Value.php
+++ b/core/lib/Drupal/Core/Render/Element/Value.php
@@ -11,8 +11,8 @@
  * Provides a form element for storage of internal information.
  *
  * Unlike \Drupal\Core\Render\Element\Hidden, this information is not sent to
- * the browser in a hidden form field, but is just stored for use in validation
- * and submit processing.
+ * the browser in a hidden form field, but only stored in the form array for use
+ * in validation and submit processing.
  *
  * Properties:
  * - #value: The value of the form element that cannot be edited by the user.