Issue #2669802 by chr.fritsch, Berdir, seanB, bojanz, dawehner, yoroy, slashrsm, tstoeckler: Add a content entity form which allows to set revisions

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

Issue #2090983 by plach, Berdir, yched: ContentEntityInterface::getTranslation() should throw an exception when an invalid language is specified

Issue #2453175 by tim.plunkett, plach, rteijeiro, effulgentsia, eshta, dawehner, fago, Berdir, alexpott: Remove EntityFormInterface::validate() and stop using button-level validation by default in entity forms

Issue #2395831 by dawehner, fago, martin107, cafuego, YesCT, plach, jibran, larowlan, Wim Leers, effulgentsia, klausi: Entity forms skip validation of fields that are not in the EntityFormDisplay

Revert "Issue #2459753 follow-up by tim.plunkett, alexpott: EntityForm::validate() should be able to modify the form structure"

This reverts commit fb5ea78b.

Issue #2459753 follow-up by tim.plunkett, alexpott: EntityForm::validate() should be able to modify the form structure

Revert "Issue #2459753 by tim.plunkett: EntityForm::validate() should be able to modify the form structure"

This reverts commit d4d83576.

Issue #2448357 by amateescu: Config entity forms need to have access to an updated entity object at all times

Issue #2230637 by plach, fran seva, yched, swentel: Create a Language field widget and the related formatter

Issue #2340667 by YesCT, Pedro Lozano, alexpott, martin107: Protect Drupal\Core\Language\Language::id, and use getId().

Issue #2123867 by plach, vijaycs85, kfritsche, YesCT, LinL, larowlan | yched: Simplify/cleanup language handling in EntityFormController.

Issue #2335659 by tim.plunkett, dawehner, effulgentsia, sun: Remove FormState ArrayAccess usage from core.

Issue #2095195 by yched, fago, Berdir, amateescu, swentel, pfrenssen, Xano: Remove deprecated field_attach_form_*().

Issue #2002134 by fago, yched, amateescu, effulgentsia: Move TypedData metadata introspection from data objects to definition objects.

Issue #2165155 by Berdir, tim.plunkett: Change $entity_type to $entity_type_id and $entity_info to $entity_type/$entity_types.

Issue #2164827 by Berdir, Xano, tim.plunkett: Rename the entityInfo() and entityType() methods on EntityInterface and EntityStorageControllerInterface.

Issue #2005716 by tim.plunkett, msonnabaum, dawehner, alexpott, effulgentsia: Promote EntityType to a domain object.

Issue #2019055 by plach, fago, berdir, yched, Gábor Hojtsy, kfritsche, jibran: Switch from field-level language fallback to entity-level language fallback.

Revert "Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback."

This reverts commit 46942cd3.

Issue #2019055 by plach, fago, kfritsche: Switch from field-level language fallback to entity-level language fallback.

Issue #1953408 by swentel, aspilicious, andypost, yched: Remove ArrayAccess BC layer from field config entities.

Issue #2004244 by Berdir, plach, tim.plunkett, msonnabaum, das-peter: Move entity revision, content translation, validation and field methods to ContentEntityInterface.