diff --git a/core/lib/Drupal/Component/Utility/SafeMarkup.php b/core/lib/Drupal/Component/Utility/SafeMarkup.php
index b4e0989..1750e13 100644
--- a/core/lib/Drupal/Component/Utility/SafeMarkup.php
+++ b/core/lib/Drupal/Component/Utility/SafeMarkup.php
@@ -169,6 +169,13 @@ public static function getAll() {
    *
    * @ingroup sanitization
    *
+   * @deprecated Will be removed before Drupal 8.0.0. If possible, rely on
+   *   Twig's auto-escaping feature, or use the '#plain_text' key when
+   *   constructing a render array that contains plain text in order to use the
+   *   renderer's auto-escaping feature. If neither of these are possible,
+   *   \Drupal\Component\Utility\Html::escape() can be used in places where
+   *   explicit escaping is needed.
+   *
    * @see drupal_validate_utf8()
    */
   public static function checkPlain($text) {