* A transition value object that describes the transition between two states.
*
* @internal
- * The workflow system is currently experimental and should only be leveraged
- * by experimental modules and development releases of contributed modules.
+ * The TransitionInterface should only be used by Workflows and Content
+ * Moderation.
+ *
+ * @todo Revisit the need for this in https://www.drupal.org/node/2902309.
*/
interface TransitionInterface {
+ /**
+ * The key of the transition plugin form.
+ */
+ const PLUGIN_FORM_KEY = 'transition';
+
/**
* Gets the transition's ID.
*