RelationshipInterface

class \Drupal\ctools\Plugin\RelationshipBase implements \Drupal\ctools\Plugin\RelationshipInterface uses \Drupal\Core\Plugin\ContextAwarePluginTrait extends \Drupal\Core\Plugin\PluginBase
class \Drupal\ctools\Plugin\Relationship\TypedDataEntityRelationship extends \Drupal\ctools\Plugin\Relationship\TypedDataRelationship
class \Drupal\ctools\Plugin\Relationship\TypedDataLanguageRelationship extends \Drupal\ctools\Plugin\Relationship\TypedDataRelationship
class \Drupal\ctools\Plugin\Relationship\TypedDataRelationship extends \Drupal\ctools\Plugin\RelationshipBase