Issue #2324365 by jhodgdon: DisplayVariant plugin class needs more info added.

core/lib/Drupal/Core/Display/Annotation/DisplayVariant.php

@@ -25,8 +25,15 @@
  * @todo: Revise description when/if Displays are added to core:
  *   https://www.drupal.org/node/2292733
  *
+ * Plugin namespace: Plugin\DisplayVariant
+ *
+ * For a working example, see
+ * \Drupal\block\Plugin\DisplayVariant\FullPageVariant
+ *
  * @see \Drupal\Core\Display\VariantInterface
+ * @see \Drupal\Core\Display\VariantBase
  * @see \Drupal\Core\Display\VariantManager
+ * @see plugin_api
  *
  * @Annotation
  */

core/lib/Drupal/Core/Display/VariantBase.php

@@ -14,6 +14,11 @@
 
 /**
  * Provides a base class for DisplayVariant plugins.
+ *
+ * @see \Drupal\Core\Display\Annotation\DisplayVariant
+ * @see \Drupal\Core\Display\VariantInterface
+ * @see \Drupal\Core\Display\VariantManager
+ * @see plugin_api
  */
 abstract class VariantBase extends PluginBase implements VariantInterface {
 

core/lib/Drupal/Core/Display/VariantInterface.php

@@ -16,7 +16,9 @@
  * Provides an interface for DisplayVariant plugins.
  *
  * @see \Drupal\Core\Display\Annotation\DisplayVariant
+ * @see \Drupal\Core\Display\VariantBase
  * @see \Drupal\Core\Display\VariantManager
+ * @see plugin_api
  */
 interface VariantInterface extends PluginInspectionInterface, ConfigurablePluginInterface, PluginFormInterface {
 

core/lib/Drupal/Core/Display/VariantManager.php

@@ -16,6 +16,8 @@
  *
  * @see \Drupal\Core\Display\Annotation\DisplayVariant
  * @see \Drupal\Core\Display\VariantInterface
+ * @see \Drupal\Core\Display\VariantBase
+ * @see plugin_api
  */
 class VariantManager extends DefaultPluginManager {