public EntityTypeInterface::getLabelCallback()
Gets the callback for the label of the entity.
The function takes an entity and returns the label of the entity. Use language() on the entity to get information on the requested language. The entity label is the main string associated with an entity; for example, the title of a node or the subject of a comment. If there is an entity object property that defines the label, use the 'label' element of the 'entity_keys' return value component to provid