diff --git a/core/modules/workflows/src/Annotation/WorkflowType.php b/core/modules/workflows/src/Annotation/WorkflowType.php
index d04910c..221f384 100644
--- a/core/modules/workflows/src/Annotation/WorkflowType.php
+++ b/core/modules/workflows/src/Annotation/WorkflowType.php
@@ -51,13 +51,16 @@ class WorkflowType extends Plugin {
   public $required_states = [];
 
   /**
-   * A list of form classes implementing PluginFormInterface.
+   * A list of optional form classes implementing PluginFormInterface.
    *
    * Forms which will be used for the workflow UI are 'configure', 'state' and
    * 'transition'.
    *
    * @see \Drupal\Core\Plugin\PluginWithFormsInterface
    * @see \Drupal\Core\Plugin\PluginFormInterface
+   * @see \Drupal\workflows\Plugin\WorkflowTypeConfigureFormBase
+   * @see \Drupal\workflows\Plugin\WorkflowTypeStateFormBase
+   * @see \Drupal\workflows\Plugin\WorkflowTypeTransitionFormBase
    *
    * @var array
    */
diff --git a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeConfigureForm.php b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeConfigureForm.php
index 2a12714..26d44c8 100644
--- a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeConfigureForm.php
+++ b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeConfigureForm.php
@@ -8,6 +8,8 @@
 
 /**
  * Form to configure the complex test workflow type.
+ *
+ * @see \Drupal\workflow_type_test\Plugin\WorkflowType\ComplexTestType
  */
 class ComplexTestTypeConfigureForm extends WorkflowTypeConfigureFormBase {
 
diff --git a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeStateForm.php b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeStateForm.php
index 8144898..fa346e5 100644
--- a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeStateForm.php
+++ b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeStateForm.php
@@ -8,6 +8,8 @@
 
 /**
  * Form to configure the complex test workflow states.
+ *
+ * @see \Drupal\workflow_type_test\Plugin\WorkflowType\ComplexTestType
  */
 class ComplexTestTypeStateForm extends WorkflowTypeStateFormBase {
 
diff --git a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeTransitionForm.php b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeTransitionForm.php
index a5655cf..195322c 100644
--- a/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeTransitionForm.php
+++ b/core/modules/workflows/tests/modules/workflow_type_test/src/Form/ComplexTestTypeTransitionForm.php
@@ -8,6 +8,8 @@
 
 /**
  * Form to configure the complex test workflow states.
+ *
+ * @see \Drupal\workflow_type_test\Plugin\WorkflowType\ComplexTestType
  */
 class ComplexTestTypeTransitionForm extends WorkflowTypeTransitionFormBase {