diff --git a/core/lib/Drupal/Core/Plugin/PluginFormInterface.php b/core/lib/Drupal/Core/Plugin/PluginFormInterface.php
index 6f314eb..d61b240 100644
--- a/core/lib/Drupal/Core/Plugin/PluginFormInterface.php
+++ b/core/lib/Drupal/Core/Plugin/PluginFormInterface.php
@@ -51,7 +51,9 @@ public function buildConfigurationForm(array $form, FormStateInterface $form_sta
    *   An associative array containing the structure of the plugin form as built
    *   by static::buildForm().
    * @param \Drupal\Core\Form\FormStateInterface $form_state
-   *   The current state of the form.
+   *   The current state of the form. The values submitted for the plugin form
+   *   can be retrieved through
+   *   \Drupal\Component\Utility\NestedArray::getValue($form_state->getValues(), $form['#parents']);
    */
   public function validateConfigurationForm(array &$form, FormStateInterface $form_state);
 
@@ -62,7 +64,9 @@ public function validateConfigurationForm(array &$form, FormStateInterface $form
    *   An associative array containing the structure of the plugin form as built
    *   by static::buildForm().
    * @param \Drupal\Core\Form\FormStateInterface $form_state
-   *   The current state of the form.
+   *   The current state of the form. The values submitted for the plugin form
+   *   can be retrieved through
+   *   \Drupal\Component\Utility\NestedArray::getValue($form_state->getValues(), $form['#parents']);
    */
   public function submitConfigurationForm(array &$form, FormStateInterface $form_state);