Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Issue #2421841 by neclimdul, tim.plunkett: Performance bug in ControllerResolver::getControllerFromDefinition()

Issue #2392787 by beejeebus, dawehner, alexpott: Move include statements from DrupalKernel::boot() into DrupalKernel::preHandle()

Issue #2281619 by dawehner, tim.plunkett: Convert most direct usages within module code of routing related request attributes to use RouteMatchInterface instead

Issue #2399219 by amateescu: Allow entity form handlers to determine the entity object they need to work with

Issue #2368275 by martin107, dawehner, znerol, Crell, Wim Leers: EntityRouteEnhancer and ContentFormControllerSubscriber implicitly depend on too many services

Issue #2363139 by Wim Leers, dawehner, larowlan: _content controllers may only return render arrays, not strings.

Issue #2361681 by Wim Leers: drupal_render(): invert second argument ($is_recursive_call -> $is_root_call) => more strict, better DX/TX.

Issue #2335659 by tim.plunkett, dawehner, effulgentsia, sun: Remove FormState ArrayAccess usage from core.

Issue #2273277 by Wim Leers, effulgentsia, Fabianx: Fixed Figure out a solution for the problematic interaction between the render system and the theme system when using #pre_render.

Issue #2212427 by Mixologic, YesCT, Sutharsan, mgriego, icseh., visabhishek, znerol: Use interface instead of class name for language manager where appropriate.

Issue #2271251 by ParisLiakos, undertext, JeroenT, StevenPatz, tim.plunkett: Remove usages of watchdog() from non-form and non-controllers.

Issue #1825952 by Fabianx, joelpittet, bdragon, heddn, chx, xjm, pwolanin, mikey_p, ti2m, bfr, dags, cilefen, scor, mgifford: Turn on twig autoescape by default

Issue #2239009 by effulgentsia, dawehner: Remove public direct usage of the '_system_path' request attribute.

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 #2267763 by pwolanin, tim.plunkett: Page titles with %placeholders are broken when used as breadcrumbs.

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