Issue #2277981 by tim.plunkett, EclipseGc, fago: Provide a service for handling context-aware plugins.

Issue #2250239 by dawehner | sun: Remove needless ContainerAware dependency from ParamConverterManager.

Issue #1921558 by ParisLiakos, xjm, Dave Reid: Convert file_get_mimetype() to use Symfony MimeTypeGuessers.

Revert "Issue #2016629 by larowlan, neclimdul, sun, alexpott, jibran, ParisLiakos, donquixote, effulgentsia, msonnabaum: Refactor bootstrap to better utilize the kernel."

This reverts commit cda051c4.

Issue #2016629 by larowlan, neclimdul, sun, alexpott, jibran, ParisLiakos, donquixote, effulgentsia, msonnabaum: Refactor bootstrap to better utilize the kernel.

Issue #2214209 by dawehner, ParisLiakos, xjm: Move _menu_site_is_offine() into the Maintainance subscriber.

Issue #2224887 by alexpott, Berdir, Gábor Hojtsy, Jalandhar: Language configuration overrides should have their own storage.

Issue #2165475 by damiankloip, dawehner, martin107, tim.plunkett, jibran, xjm, Jalandhar: Provide a generic class resolver.

Issue #1289536 by ParisLiakos, RobLoach, Crell, larowlan, fgm, pounard, Pancho, dawehner, scor, tim.plunkett, alexpott, socketwench: Switch Watchdog to a PSR-3 logging framework.

Revert "Issue #1289536 by RobLoach, Crell, Pancho, pounard, socketwench, fgm, dawehner, scor, tim.plunkett, larowlan, ParisLiakos: Switch Watchdog to a PSR-3 logging framework."

This reverts commit ef250ba2.

Issue #1289536 by RobLoach, Crell, Pancho, pounard, socketwench, fgm, dawehner, scor, tim.plunkett, larowlan, ParisLiakos: Switch Watchdog to a PSR-3 logging framework.

Issue #1807662 by sun, beejeebus, damiankloip, Wim Leers, Mixologic: Built-in APCu support in core (PHP 5.5 only).

Issue #2222719 by effulgentsia, tim.plunkett, xjm, dawehner: Use parameter matching via reflection for access checks instead of pulling variables from request attributes.

Issue #2257835 by tim.plunkett, sun, Jalandhar: Move form submission logic out of FormBuilder into a new class.

Issue #2263255 by alexpott: Cache.config only has a single key in it for config schema this seems a waste.

Issue #2257709 by znerol, Wim Leers: Remove the interdependence between the internal page cache and management of the Cache-Control header for external caches.

Issue #2168809 by sun, damiankloip: Do not add the Guzzle HTTP client request subscriber outside of test environment.

Issue #2079797 by ParisLiakos, Xano, amateescu, tim.plunkett: Provide a trait for $this->t() and $this->formatPlural().

Issue #2039021 by tim.plunkett, Berdir, Xano | akshay.swnt22: Convert ActionManager to extend DefaultPluginManager.

Issue #2228261 by beejeebus, kim.pepper, alexpott, Wim Leers: Add a local, PhpStorage-based cache backend.

Issue #2213319 by sun, dawehner: Create a single Container CompilerPass to collect + add handlers to consumer service definitions.