Issue #2901730 by mfernea, ankitjain28may, idebr: Fix 'Squiz.WhiteSpace.FunctionSpacing' coding standard

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 #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 #1392754 by tss, justAChris, jhodgdon: Comply with new documentation standards for @file for namespaced class files

Issue #2459971 by Gábor Hojtsy: The langcode key on configuration files is not explicit in configuration schema

Issue #2392319 by alexpott, effulgentsia: Config objects (but not config entities) should by default be immutable

Issue #2404407 by effulgentsia: language_set_browser_drupal_langcode_mappings() is a useless wrapper, so remove it

Issue #365615 followup by attiks, YesCT, Gábor Hojtsy, mgifford, Albert Volkman, plach, webwarrior, David_Rothstein, penyaskito, smokris | yang_yi_cn: Fixed Followups: Language detection not working correctly for most Chinese readers (and add a user interface for all browser language mappings).

Issue #1963394 by tim.plunkett, jibran, effulgentsia: Fixed ConfirmFormBase::getCancelPath() should allow for a route.

Issue #1946426 by ramlev, pfrenssen, foopang, webflo, David Hernández, vijaycs85, disasm, tim.plunkett: Convert all of confirm_form() in language.admin.inc to the new form interface.