+ /**
+ * An EntityContextDefinition instance, for backwards compatibility.
+ *
+ * If this context is created with a data type that starts with 'entity:',
+ * this property will be an instance of EntityContextDefinition, and certain
+ * methods of this object will delegate to their overridden counterparts in
+ * $this->entityContextDefinition.
+ *
+ * This property should be kept private so that it is only accessible to this
+ * class for backwards compatibility reasons. It will be removed in Drupal 9.
+ *
+ * @deprecated
+ * Constructing a context definition for an entity type (i.e., the data type
+ * begins with 'entity:') is deprecated in Drupal 8.6.0. Instead, use
+ * the static factory methods of EntityContextDefinition to create context
+ * definitions for entity types, or the static ::create() method of this
+ * class for any other data type. See https://www.drupal.org/node/2976400
+ * for more information.
+ *
+ * @see ::__construct()
+ * @see ::__sleep()
+ * @see ::__wakeup()
+ * @see ::getConstraintObjects()
+ * @see ::getSampleValues()
+ * @see ::initializeEntityContextDefinition()
+ * @see https://www.drupal.org/node/2932462
+ * @see https://www.drupal.org/node/2976400
+ *
+ * @var \Drupal\Core\Plugin\Context\EntityContextDefinition
+ */
+ private $entityContextDefinition;
+