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.

Issue #1067408 by alexpott, Jalandhar, jessebeach, Désiré, neetu morwani, dawehner, sun: Themes do not have an installation status.

Issue #2245117 by znerol: Remove the optional $skip_anonymous parameter from CsrfTokenGenerator::validate and remove the dependency on current_user service.

Issue #2231419 by sun, jibran, Rajendar Reddy, Jalandhar, damiankloip: Merge obsolete CachedModuleHandler into ModuleHandler.

Issue #2161591 by pwolanin, beejeebus, sun: Change default active config from file storage to DB storage.

Issue #2228341 by sun, znerol, skipyT, ParisLiakos: Objectify session management functions + remove session.inc.

Issue #2209145 by slashrsm, fgm, chx: Move all path alias SQL queries to a single storage controller.

Issue #1081192 by wojtha, klausi, larowlan, nedjo, Heine: Verify peer on HTTPS if cURL available (but be careful of built-in cert bundles in the codebase).

Issue #2054011 by amateescu, pwolanin, dawehner, YesCT, tim.plunkett, blueminds, Berdir, das-peter, effulgentsia: Implement built-in support for internal URLs.