Issue #2171015 by alexpott: Drupal 8 HEAD broken: installing Language module fails, after that cannot install any other module.

Issue #2001206 by andypost, penyaskito, herom, Crell, ebeyrent, DmitryDrozdik: Replace drupal_container() with Drupal::service().

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, alexpott, larowlan, Damien Tournoud: Replace almost all remaining superglobals (, , etc.) with Symfony Request object.

Issue #1998638 by damiankloip, dawehner, kim.pepper, cosmicdreams, larowlan, Damien Tournoud: Replace all remaining superglobals (, , etc.) with Symfony Request object.

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

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

Issue #2045931 by PerthSam152, LinL, adsw12, joelpittet: Replace all module_exists() deprecated function calls.

This reverts commit cc84f390 - bad
commit message.

Issue #2089351 by thedavidmeister, meba: Convert all calls to check_plain() in core to Drupal\Component\Utility\String::checkPlain() in core/includes.

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

Issue #2038135 by RobLoach, donquixote, Crell, ParisLiakos, catch: Use the Composer autoloader to make everything simpler.

Issue #2032535 by dawehner, katbailey, pwolanin, Crell: Resolve 'title/title callback' by adding a _title propery on the route and allow a title be part of the render array.

Issue #1476810 by Spleshka, franz: Fixed drupal_serve_page_from_cache() can serve uncompressed data with Content-Encoding gzip header with page_cache_without_database = 1.

Issue #1855260 by beejeebus, msonnabaum, larowlan: Fixed Page caching broken by accept header-based routing.

Issue #2056845 by StephaneQ | tstoeckler: Fixed Stale documentation in drupal_bootstrap() regarding DRUPAL_ROOT.

Issue #1934712 by dlu, alexpott, pplantinga, rbayliss, s_leu, Gaelan: Fixed Merge system.timezone config object into system.date.

Issue #2006024 by kgoel, rbayliss, wesleydv: Fixed drupal_container() is deprecated, don't use it in bootstrap.php.

Issue #1856976 by andypost, Soul88, ACF, aspilicious, vijaycs85, dawehner: Convert language_count() to the state system.