Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2326949 by plach, effulgentsia: Move entity-type-specific schema information from the storage class to a schema handler.

Issue #2183231 by tstoeckler, plach, jessebeach, fago, Berdir, xjm, mauzeh: Make ContentEntityDatabaseStorage generate static database schemas for content entities.

Issue #1957312 by ParisLiakos, peximo, Désiré: Use the entity storage controller in aggregator module.

Issue #2041083 by marcingy, grisendo, herom: Move database query out of \Drupal\aggregator\FeedFormController.

Issue #1847002 by tim.plunkett, effulgentsia, msonnabaum: Move entity type classes from Drupal$provider\Plugin\Core\Entity to Drupal$provider\Entity.

Issue #1893772 by chx, fubhy, slashrsm: Move entity-type specific storage logic into entity classes.

Issue #293318 by alex_b, Berdir, rootatwc, Aron Novak, mustafau, akahn: Convert Aggregator feeds into entities.