Issue #2004086 by dawehner, pwolanin, katbailey, tim.plunkett, vijaycs85, fabpot: The Request service must be synthetic.

Issue #1954892 by dawehner, tim.plunkett, David_Rothstein, effulgentsia: Replace 'theme callback' and hook_custom_theme() with a clean theme negotiation system.

Issue #2129039 by plach, jthorson, pfrenssen, nyirocsaba, Gábor Hojtsy: Integrity constraint violation when translating body field.

Revert "Issue #2129039 by plach, jthorson, pfrenssen, nyirocsaba, Gábor Hojtsy: Integrity constraint violation when translating body field."

Testbot does not like this patch. Needs further investigation.

This reverts commit b0ed7570.

Issue #2137599 by segi, Sweetchuck: Incorrect type and default value for the direction of the default language.

Issue #2135787 by amateescu, Gábor Hojtsy, YesCT: Move static config entity local tasks to local_tasks().yml.

Issue #2129039 by plach, jthorson, pfrenssen, nyirocsaba, Gábor Hojtsy: Integrity constraint violation when translating body field.

Issue #2138133 by Gábor Hojtsy: Clean up maintainers.txt and changelog.txt for multilingual changes.

Issue #2118703 by Wim Leers, amateescu: Introduce #post_render_cache callback to allow for personalization without breaking the render cache.

Issue #2093167 by johnnydarkko, thedavidmeister, Vibjerg: Deprecate check_plain(), call \Drupal\Component\Utility\String::checkPlain() directly instead.

Issue #1952394 by vijaycs85, tstoeckler, webflo, Gábor Hojtsy, Schnitzel, falcon03, YesCT, kfritsche, Ryan Weal, dagmita, likin, toddtomlinson, nonsie, Kristen Pol, dawehner, tim.plunkett, penyaskito, EclipseGC, larowlan, robertdbailey, helenkim, David Hernández, EllaTheHarpy, lazysoundsystem, juanolalla, R.Hendel, Kartagis: Add configuration translation user interface module.

Issue #1886448 by dawehner, sun, Berdir, ParisLiakos: Rewrite the theme registry into a proper service.

Issue #2073531 by tim.plunkett, dawehner, Berdir, catch, plach: Use current user service instead of _account, remove _account from the request object.

Issue #2133469 by tim.plunkett, damiankloip, dawehner: Replace path-based entity links with route names.

Issue #2101427 by David_Rothstein, evilehk, nod_: Follow-up: Browser validation error with Chrome on hidden required fields, even on forms that don't allow client-side validation.

Issue #2020111 by damiankloip, a_c_m, dawehner, tim.plunkett: Allow the "With selection" label on bulk operation to be configured.