Issue #2472323 by dawehner, neclimdul, Crell, kim.pepper, nod_, Wim Leers, larowlan, jibran, pwolanin, catch: Move modal / dialog to query parameters

Issue #2066445 by mparker17, rpayanm, aspilicious, tkuldeep17, adci_contributor, Mile23, vijaycs85, alvar0hurtad0, rahulbile, andypost, valthebald: Convert a bunch of AjaxResponse callbacks in system.module's test's ajax_test.module to a new style controller

Issue #1987612 by valthebald, Mile23, aspilicious, Pinolo, InternetDevels: Convert ajax_test_dialog_contents() to a new style controller

Issue #2347469 by mondrake, Wim Leers, larowlan, kattekrab, mnico, tadityar: Rendering forms in AjaxResponses does not attach assets automatically

Issue #784626 by Wim Leers, Manuel Garcia, jcisio, joelpittet, Bevan, fcaspani, dcmouyard: Default all JS to the footer, allow asset libraries to force their JS to the header

Issue #2368797 by Wim Leers, dawehner, rteijeiro: Optimize ajaxPageState to keep Drupal 8 sites fast on high-latency networks, prevent CSS/JS aggregation from taking down sites and use HTTP GET for AJAX requests

Issue #2384545 by Wim Leers, jbrown: $element['#ajax']['callback'] is broken, hence breaking e.g. inserting images in CKEditor

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

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

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.

This reverts commit ae8be3cc.

Issue #1939064 by joelpittet, pwieck, farrington, mark.labrecque, Cottser, InternetDevels, mdrummond, drupalninja99, BarisW, jenlampton: Convert theme_links() to Twig.

Issue #1987606 by vijaycs85, mparker17, InternetDevels, rdickert: Convert ajax_test_dialog() to a new style controller.

Issue #2168113 by penyaskito, jessebeach, catch: Add leading underscore and other discouragement to drupal_add_css() and drupal_add_js().

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

Issue #2095335 by Wim Leers, vijaycs85: Remove drupal_add_css() and drupal_add_js() from the ajax system.

Issue #2102479 by InternetDevels, dipen chaudhary: Remove drupal_set_title in system/ajax_test module controllers.

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.

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

This reverts commit fc04601c.

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

Issue #2095121 by clemens.tolboom, jibran: Ensure every path in routing.yml files has a leading slash.