Provide views data that isn't tied to any other module. File core/modules/views/views.views.inc
views_views_data_alter(&$data) Implements
views_field_default_views_data(FieldStorageConfigInterface $field_storage) Default views data implementation
core_field_views_data(FieldStorageConfigInterface $field_storage) Implements
_views_field_get_entity_type_storage(FieldStorageConfigInterface $field_storage) Determines whether the entity
views_views_data() Implements
views_entity_field_label($entity_type, $field_name) Returns the label of a certain field.