diff -u b/core/modules/tour/src/TourTipPluginInterface.php b/core/modules/tour/src/TourTipPluginInterface.php
--- b/core/modules/tour/src/TourTipPluginInterface.php
+++ b/core/modules/tour/src/TourTipPluginInterface.php
@@ -9,6 +9,9 @@
  * @see \Drupal\tour\TipPluginBase
  * @see \Drupal\tour\TipPluginManager
  * @see plugin_api
+ *
+ * @todo move all methods to TipPluginInterface and deprecate this interface in
+ *   https://drupal.org/i/3261249
  */
 interface TourTipPluginInterface extends TipPluginInterface {