BlockVariantInterface

class \Drupal\ctools\Plugin\DisplayVariant\BlockDisplayVariant extends \Drupal\Core\Display\VariantBase implements \Drupal\Core\Display\ContextAwareVariantInterface, \Drupal\Core\Plugin\ContainerFactoryPluginInterface, \Drupal\ctools\Plugin\BlockVariantInterface uses \Drupal\ctools\Form\AjaxFormTrait, \Drupal\ctools\Plugin\BlockVariantTrait
class \Drupal\ctools_block_display_test\Plugin\DisplayVariant\BlockDisplayVariant extends \Drupal\ctools\Plugin\DisplayVariant\BlockDisplayVariant