Issue #2252081 by Xano: Move implementation-specific docs out of PluginFormInterface

core/lib/Drupal/Component/Plugin/PluginBase.php

@@ -33,6 +33,13 @@ abstract class PluginBase implements PluginInspectionInterface, DerivativeInspec
   /**
    * Configuration information passed into the plugin.
    *
+   * When using an interface like
+   * \Drupal\Component\Plugin\ConfigurablePluginInterface, this is where the
+   * configuration should be stored.
+   *
+   * Plugin configuration is optional, so plugin implementations must provide
+   * their own setters and getters.
+   *
    * @var array
    */
   protected $configuration;
@@ -89,7 +96,4 @@ public function getDerivativeId() {
   public function getPluginDefinition() {
     return $this->pluginDefinition;
   }
-
-  // Note: Plugin configuration is optional so its left to the plugin type to
-  // require a getter as part of its interface.
 }

core/lib/Drupal/Core/Plugin/PluginFormInterface.php

@@ -38,11 +38,6 @@ public function validateConfigurationForm(array &$form, array &$form_state);
   /**
    * Form submission handler.
    *
-   * To properly store submitted form values store them in $this->configuration.
-   * @code
-   *   $this->configuration['some_value'] = $form_state['values']['some_value'];
-   * @endcode
-   *
    * @param array $form
    *   An associative array containing the structure of the form.
    * @param array $form_state