Issue #2465467 by willzyx, Dom., andypost: SystemInfoController::php() should check if function phpinfo() exists

Issue #2461063 by Wim Leers, effulgentsia: AJAX forms using #ajax broken when page caching is enabled

Issue #2090115 by alexpott, xjm: Don't install a module when its default configuration has unmet dependencies

Issue #356399 by dawehner, beejeebus, catch, sidharrell, klausi, nlisgo, Josh Waihi, Berdir, martin107: Optimize the route rebuilding process to rebuild on write

Issue #2289917 by Wim Leers, mdrummond, lauriii, Manuel Garcia, emma.maria, Scionar, davidhernandez: Convert "messages" page element into blocks

Issue #2403301 by lokapujya, penyaskito, Wim Leers: Menu item "active" class is not correctly added when using a view as the frontpage

Issue #1959806 by amateescu, jibran, goldorak, Wim Leers, yched, dawehner: Provide a generic 'entity_autocomplete' Form API element

Issue #2412241 by idebr, Wim Leers: Active menu links with identical paths get a duplicate "active" class for every active menu link

Issue #2364157 by mpdonadio, dawehner, martin107, Berdir, pcambra, naveenvalecha, tim.plunkett: Replace most existing _url calls with Url objects

Issue #2140511 by alexpott, Gábor Hojtsy, swentel, babruix, ohthehugemanatee, jessebeach, Berdir: Configuration file name collisions silently ignored for default configuration

Issue #2392319 by alexpott, effulgentsia: Config objects (but not config entities) should by default be immutable

Issue #2335673 by ashutoshsngh, oenie, rudins, er.pushpinderrana: Remove usage of drupal_process_form()

Issue #2328111 by dawehner, martin107, neclimdul: Replace most instances of the DRUPAL_ROOT constant with the app.root container parameter.

Issue #2362517 by Wim Leers: Improve default 403/404 exception HTML subscriber: don't duplicate the page render pipeline, use the routing system — add system.403 and system.404 routes.

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

Issue #2355179 by legolasbo, er.pushpinderrana: Remove usage of form_get_cache() and form_set_cache().

Issue #2242749 by znerol, torotil, rszrama, larowlan, dawehner, penyaskito, tim.plunkett, sun, Damien Tournoud, David_Rothstein,  effulgentsia: Fixed Port Form API security fix SA-CORE-2014-002 to Drupal 8.

Issue #2347465 by tim.plunkett, dawehner, cilefen: Convert all instances of #type link/links to convert to use routes.

Issue #2329851 by lanchez, lauriii, Jolidog | davidhernandez: Move miscellaneous system classes from preprocess to templates.

Issue #2335003 by joshi.rohit100, rootwork, tuutti | joelpittet: Rename task-list.html.twig to maintenance-task-list.html.twig.

Issue #2340251 by iMiksu, alexpott, tim.plunkett, dawehner, Wim Leers: Remove most remaining url() calls.

Issue #2333113 by effulgentsia, plach: Add an EntityDefinitionUpdateManager so that entity handlers can respond (e.g., by updating db schema) to code updates in a controlled way (e.g., from update.php).

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 #2309323 by Berdir, tim.plunkett: Allow #submit and #validate to be specified as methods of the form object.

Issue #1498664 by andypost, plach, penyaskito | dawehner: Refactor user entity properties to multilingual.

Issue #2305707 by cilefen, pwolanin, dawehner, LinL: MenuLinkContent disabled field should be renamed to enabled and use positive logic.

Issue #2272481 by herom, ParisLiakos, tim.plunkett: Remove usages of watchdog() from forms, plugins and controllers.