Issue #3073053 by pivica, Primsi, unstatu, pooja saraah, smustgrave, Berdir: Theme library override can fail in when you have multiple parent themes

Issue #3409982 by claudiu.cristea, longwave, alexpott, catch, Ghost of Drupal Past: [D10.2 regression] Theme suggestions cannot alter variables anymore

Issue #3157353 by Utkarsh_33, lauriii, dww, smustgrave, longwave, narendraR, quietone, larowlan, catch, Berdir, omkar.podey: Provide a mechanism to mark entire twig templates as deprecated

Issue #2953921 by andypost, donquixote, borisson_, effulgentsia: Refactor out theme hook suggestion building from ThemeManager::render() into a separate function

Issue #3346645 by jweowu, catch, smustgrave: Eliminate anti-pattern isset($arr[$key]) || array_key_exists($key, $arr)

Issue #2760659 by lauriii, yogeshmpawar, vmachado, anya_m, alexpott, Fabianx, joelpittet, xjm: Allow the use of callbacks instead of global functions in preprocess function callbacks

Issue #3097889 by longwave, paulocs, anushrikumari, SenthilMohith, andypost, Gábor Hojtsy, catch, lauriii, Wim Leers: Remove deprecated theme functions

Issue #2704871 by pepegarciag, Mile23, Manuel Garcia, ieguskiza, snehi, gaurav.pahuja, dimaro, rajeshwari10, gargsuchi, pashupathi nath gajawada, penyaskito, xjm, ZeiP, Wim Leers, alexpott: Replace usages of deprecated method drupal_render()

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

Revert "Issue #2704871 by pepegarciag, ieguskiza, snehi, gaurav.pahuja, rajeshwari10, dimaro, gargsuchi, pashupathi nath gajawada, penyaskito, Manuel Garcia, Mile23: Replace usages of deprecated method drupal render()"

This reverts commit ae3ee317.

Issue #2704871 by pepegarciag, ieguskiza, snehi, gaurav.pahuja, rajeshwari10, dimaro, gargsuchi, pashupathi nath gajawada, penyaskito, Manuel Garcia, Mile23: Replace usages of deprecated method drupal render()

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2388247 by pguillard, snehi, joelpittet, sriharsha.uppuluri: Documentation refers to _theme() function, which has been removed

Issue #2576533 by alexpott, stefan.r, Wim Leers, dawehner, xjm, effulgentsia, catch: Rename SafeStringInterface to MarkupInterface and move related classes

Issue #939462 by lauriii, Antti J. Salminen, NROTC_Webmaster, mbrett5062, tim.plunkett, tostinni, rteijeiro, dvessel, cilefen, barraponto, theapi, joelpittet, Xano, tuutti, drzraf, Fabianx, markcarver, xjm, catch, Cottser, sun, jenlampton, effulgentsia, davidhernandez, kscheirer, akalata, andypost, hass, rooby, jhodgdon, fubhy, becw, MXT, mlncn, lemunet, chriscalip, mike stewart, PavanL, kevinquillen, gleroux02: Specific preprocess functions for theme hook suggestions are not invoked

Issue #2501931 by alexpott, alimac, cmanalansan, davidhernandez, scotself, cilefen, RavindraSingh, peezy, YesCT, pwolanin: Remove SafeMarkup::set in twig_render_template() and ThemeManager and FieldPluginBase:advancedRender

Revert "Issue #2501931 by alexpott, alimac, cmanalansan, davidhernandez, scotself, cilefen, RavindraSingh, peezy, YesCT, pwolanin: Remove SafeMarkup::set in twig_render_template() and ThemeManager and FieldPluginBase:advancedRender"

This reverts commit 9ccb44e2.

Issue #2501931 by alexpott, alimac, cmanalansan, davidhernandez, scotself, cilefen, RavindraSingh, peezy, YesCT, pwolanin: Remove SafeMarkup::set in twig_render_template() and ThemeManager and FieldPluginBase:advancedRender

Issue #2351015 by plach, effulgentsia, Wim Leers, dawehner, martin107, damiankloip, cilefen, Fabianx, catch, pwolanin, Damien Tournoud, znerol, YesCT, larowlan: URL generation does not bubble cache contexts

Issue #2509434 by willzyx: Faulty dependency to ThemeInitialization in Drupal\Core\Theme\ThemeManager

Issue #2448847 by dawehner, arlinsandbulte: [regression] Themes unable to implement hook_theme_registry_alter()

Issue #2346937 by dawehner, larowlan, Wim Leers, claudiu.cristea, msonnabaum: Implement a Renderer service; reduces drupal_render / _theme service container calls

Issue #2329303 by tim.plunkett, dawehner: Fixed Use the right request when determining the theme on a 403 page.