Issue #2935256 by Jo Fitzgerald, voleger, kim.pepper, ibustos, Yogesh Pawar, catch, jibran: Remove all usages of drupal_get_message and drupal_set_message in modules

Issue #2873696 by nvexler, wengerk, gido, Jo Fitzgerald, xjm: Add @internal to core classes, methods, properties to Form Classes

Issue #2575535 by bighappyface, heykarthikwithu, rodrigoaguilera, prasad_gogate:  Custom language settings configuration is not saved when you have a language selector enabled for any content

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 #1919468 by alexpott, Berdir: EntityManager::getAllBundleInfo() adds default entity_type_id bundle for entity types with bundles

Issue #2485409 by rudraram, Manjit.Singh, LewisNyman: Clean up content translation CSS inline with our CSS standards

Issue #2397729 by penyaskito, Gábor Hojtsy, plach, Kristen Pol: Content language settings cannot be configured for non-translatable types on the one page configuration form

Issue #2355909 by penyaskito, alexpott, Gábor Hojtsy, DuaelFr: language.settings config is not scalable

Issue #2241727 by mon_franco | YesCT: Remove button name override and update tests for that rename of Save to Save configuration in .

Issue #1987726 by vijaycs85, disasm, YesCT, pdrake, tstoeckler, dawehner, Xano, likin, stella, andypost, prateek479, Gábor Hojtsy, kgoel: Convert language content page related callback to new style controller.

Issue #2239065 by tim.plunkett | webchick: Overridden config bleeding through to configuration forms.

Issue #2203407 by nod_, sun: Replace #attached library array values with provider-namespaced strings.

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

Issue #2098119 by beejeebus, alexpott, chx: Replace config context system with baked-in locale support and single-event based overrides.

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

Issue #2084279 by herom, andypost, David Hernández, dawehner, Xano: Remove plugin.manager.entity service in favor of entity.manager.

Issue #2066535 by tim.plunkett, jsst, Berdir: Add EntityManagerInterface and stop typehinting with EntityManager.

Issue #2089627 by tim.plunkett: Move \Drupal\system\SystemConfigFormBase to \Drupal\Core\Form\ConfigFormBase.

Issue #1978916 by likin, YesCT, disasm, ayelet_Cr, tim.plunkett, vijaycs85, Letharion: Convert locale_translate_page() to a Controller.