Issue #2478119 by znerol, andypost: Replace references to Session Manager with references to Session

Issue #2483433 by damiankloip, Wim Leers, catch, dawehner: Optimize CacheableMetadata::merge() + BubbleableMetadata::merge()

Issue #2395831 by dawehner, fago, martin107, cafuego, YesCT, plach, jibran, larowlan, Wim Leers, effulgentsia, klausi: Entity forms skip validation of fields that are not in the EntityFormDisplay

Issue #2195573 by Xano, eiriksm, heddn, ParisLiakos, Les Lim, Pere Orga, dinarcon, xjm, alexpott: Add a dedicated @LanguageNegotiation annotation class

Issue #2460529 by alexpott, chx, phenaproxima: Migrations need to use the configuration entity dependency system

Issue #2478483 by Wim Leers, Fabianx: Introduce placeholders (#lazy_builder) to replace #post_render_cache

Issue #2473729 by FMB, darol100, ifrik, ivarlaks, jhodgdon: Review the hook_help for Internal page cache module

Issue #2499615 by honzakuchar: Docblock interface Drupal\Core\Extension\ThemeHandlerInterface::uninstall typo

Issue #2389811 by znerol, mpdonadio, alexpott, hussainweb, neclimdul: Move all the logic out of index.php (again)

Issue #2218145 by mglaman, fran seva, Alumei, dawehner: Change EntityRouteEnhancer::enhance() to use protected methods instead of one giant method

Issue #2476059 by willzyx, tadityar, yarik.lutsiuk, Berdir: Remove EntityInterface->getSystemPath(), all its implementations and related usage

Issue #2475715 by stefan.r, tstoeckler: Module uninstall form does not validate correctly and breaks the confirmation form after 60 seconds

Issue #2495419 by Cottser: Move the 'search-results' class from the render array and into a Classy template

Issue #2477461 by borisson_, googletorp, Wim Leers, Crell: Move X-Generator header to its own listener

Issue #2498689 by lauriii, Wim Leers, David_Rothstein: "Back to site" link no longer appears in the toolbar

Issue #2115737 by darol100, rhuffstedtler, andythomnz, jemandy, ijf8090, zealfire, er.pushpinderrana, jhodgdon: Make the text in modules, themes, and profiles README.txt files more user-friendly

Issue #2497447 by mpdonadio, stefan.r, jhodgdon: DrupalDateTime::format() and DateTimePlus::format() ignore the timezone setting

Issue #2489664 by sumitmadan, davidhernandez, Manjit.Singh, Cottser: Remove unnecessary markup from core templates, a.k.a. divitis

Issue #2485375 by marieke_h, Manjit.Singh, MathieuSpil, LewisNyman, geertvd: Clean up shortcut CSS inline with our CSS standards

Revert "Issue #1314214 by stefan.r, phayes, ergophobe, YesCT, damienwhaley, Tor Arne Thune, kbasarab, pfrenssen, basic, yannickoo, simolokid: MySQL driver does not support full UTF-8 (emojis, asian symbols, mathematical symbols)"

This reverts commit b105158a.

Issue #2139185 by penyaskito, YesCT: Notify users when landing on config translation page with only one language listed

Issue #2498269 by willzyx: Syslog is incompatible with Webprofiler - Faulty dependency to ConfigFactory

Issue #1314214 by stefan.r, phayes, ergophobe, YesCT, damienwhaley, Tor Arne Thune, kbasarab, pfrenssen, basic, yannickoo, simolokid: MySQL driver does not support full UTF-8 (emojis, asian symbols, mathematical symbols)

This reverts commit e3391535.

Issue #2497113 by catch, dawehner: views_theme() gets 19 types of plugin definition, only needs five

Issue #2254865 by Wim Leers, lauriii, borisson_, JeroenT, alexpott, Fabianx: toolbar_pre_render() runs on every page and is responsible for ~15ms/17000 function calls

Issue #2429443 by vijaycs85, rteijeiro, penyaskito, gloob, xjm, nod_, geertvd, pjonckiere, alexpott, Wim Leers, Gábor Hojtsy, Fabianx, tim.plunkett: Date format form is unusable