Issue #3104307 by Berdir, longwave, Gábor Hojtsy, Wim Leers, alexpott, andypost: Remove  BC layers in various Drupal\Core components

Issue #2940038 by Sweetchuck, drunken monkey, rajeshwari10, borisson_: Use $this in @return PhpDoc comments instead of the name of the current class or interface

Issue #3061117 by claudiu.cristea, darrenwh: Make optional and deprecate the BackendChain constructor parameter

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 #2572633 by vprocessor, andypost, attiks, andriyun: Fix 'Drupal.Commenting.ClassComment' coding standard

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

Issue #2502621 by Pravin Ajaaz, hussainweb, Peacog, jhodgdon, ivanjaros: Replace implement notes with inheritdoc tag

Issue #2541432 by Wim Leers: Follow-up for #2231595: Document why ChainedFastBackend cannot use BackendChain

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

Issue #1167248 by Berdir, damiankloip, Alan Evans, beejeebus, catch: Add CacheBackendInterface::setMultiple().

Issue #2169447 by damiankloip, sun, longwave: DX: Supply CacheBackendInterface::CACHE_PERMANENT as Cache::PERMANENT.

Issue #2079857 by herom, mrsinguyen, martin107, simanjan, sandipmkhairnar: BackendChain::removeBin() is broken.

Issue #2100329 by cosmicdreams: Use \Drupal instead of Drupal to make IDEs and static code analyse tools happy.

Issue #1167144 by chx, catch, claudiu.cristea: Make cache backends responsible for their own storage.