Issue #3303874 by alecsmrekar, Wim Leers, smustgrave: Early rendering issue in big_pipe_page_attachments() for controllers returning Response objects

Issue #3305648 by _utsavsharma, immaculatexavier, smustgrave, quietone: Remove common_test_drupal_render_printing_pre_render

Issue #1014086 by catch, nod_, martin107, quietone, dww, mariacha1, Spokje, yogeshmpawar, pounard, Wim Leers, mfer, mikeytown2, mbutcher, moshe weitzman, Fabianx, borisson_, alexpott, donquixote, sun, andypost, dawehner: Stampedes and cold cache performance issues with css/js aggregation

Issue #3278124 by catch, nod_, andregp, quietone, deviantintegral, alexpott: Convert various tests that use bartik/seven to olivero/claro

Issue #2347783 by kim.pepper, andypost, almaudoh, gumanist, aleevas, rodrigoaguilera, Berdir, saurabh-2k17, Spokje, dhirendra.mishra, alexpott, paulocs, izus, Wim Leers, KapilV, naveenvalecha, anmolgoyal74, subson, yo30, harsha012, mrinalini9, daffie, voleger, dww, fietserwin, tim.plunkett, joachim, larowlan: Deprecate drupal_get_path() and drupal_get_filename() and replace with ExtensionList::getPath() and ExtensionList::getPathname()

Issue #2623718 by attiks, vsujeetkumar, andypost, MerryHamster, ankithashetty, anmolgoyal74, pfrenssen, longwave, alexpott, borisson_: Fix 'Drupal.Commenting.HookComment' coding standard

Issue #2055851 by andypost, jungle, dawehner, Mac_Weber, sja112, borisson_, fietserwin, init90, Gábor Hojtsy, xjm, effulgentsia, tim.plunkett: Remove translation of exception messages

Issue #3109480 by longwave, catch, bnjmnm, xjm, lauriii, Gábor Hojtsy: Properly deprecate theme functions for Drupal 10

Issue #3110862 by longwave, alexpott, catch, Mile23, Lendude, Gábor Hojtsy, Berdir: Remove simpletest module from core

Issue #2776975 by joelpittet, dawehner, tim.plunkett, xjm, pfrenssen: March 3, 2017: Convert core to array syntax coding standards for Drupal 8.3.x RC phase

Issue #2716685 by Mile23: Part 2: Fix several errors in the 'Drupal.Commenting.DocComment' coding standard

Issue #2378883 by Wim Leers, dawehner: Convert existing drupal_render() KernelTestBase tests to PHPUnit tests

Issue #2419897 by penyaskito, Wim Leers, webflo: Javascript translations are loaded in the wrong order due to missing dependencies

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 #2358981 by tadityar, tstoeckler, larowlan, mpdonadio, Devin Carlson: Provide a mechanism for dynamic library declarations

Issue #2382667 by Wim Leers, Berdir: #post_render_callback's that result from other #post_render_calback are not processed

Issue #2350949 by Wim Leers: Add hook_page_attachments(_alter)() and deprecate hook_page_build/alter().

Issue #2246675 by rpayanm, johnstorey, holly.ross.drupal | mgbellaire: Remove all unnecessary 'template' lines in hook_theme() declarations.

Issue #2346369 by Wim Leers: Support special '#attached' variable for attaching assets in preprocess functions.

Issue #2226207 by lauriii, mgbellaire, Cottser, m1r1k, Mark Carver, LinL, rachel_norfolk, rteijeiro, skwashd, davidhernandez, euphoric_mv: Make 'template' the default output option for hook_theme().

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 #2099131 by jessebeach, Wim Leers, catch, Berdir, benjifisher, martin107, andypost: Use #pre_render pattern for entity render caching.

Issue #2203407 by nod_, sun: Replace #attached library array values with provider-namespaced strings.

Issue #2045927 by herom, martin107, ianthomas_uk, Xano, michaellander, Sutharsan: Replace all drupal_alter() deprecated function calls.

Issue #1996238 by sun, nod_, damiankloip, Wim Leers, longwave, alexpott, Xano, mdrummond, Mark Carver, Jeff Burnz, highrockmedia, joelpittet, et al: Replace hook_library_info() by *.libraries.yml file.

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

Issue #1987656 by mparker17: Convert common_test_js_and_css_querystring() to a new style controller.

Issue #2066523 by mparker17, disasm: Convert common_test_drupal_render_invalid_keys() to a new style controller.

Issue #2012812 by thedavidmeister, pwieck: drupal_render() can't distinguish between empty strings from theme() from an implemented hook and no hook being matched.