Issue #2013094 by pwieck, Cottser: Remove unnecessary template_preprocess() reference from all Twig files

Issue #1668866 by ParisLiakos, aspilicious, tim.plunkett, pdrake, g.oechsler, dawehner, Berdir, corvus_ch, damiankloip, disasm, marcingy, neclimdul: Replace drupal_goto() with RedirectResponse.

Issue #1981342 by aspilicious, andypost, swentel: Drop procedural usage of fields in [s-u-v] modules.

Issue #2009666 by aaronott, jiff, jeroen12345: Replace theme() with drupal_render() in search module.

Issue #1933518 by ACF, pwolanin, mparker17: Convert search's system_config_form() to SystemConfigFormBase.

Issue #2001320 by zschmid, chrisguindon, pwieck, chertzog: Rename Views method add_groupby() to addGroupBy().

Issue #2002144 by phenaproxima, connork, rdrh555, zschmid, elvis2, drupalway, heddn: Rename Views method add_field() to addField().

Issue #2002190 by dawehner, jhedstrom: Convert core/modules/search/lib/Drupal/search/Tests/SearchExpressionTest.php to phpunit.

Issue #1818570 by Berdir, effulgentsia, das-peter, andypost: Convert users to the new Entity Field API.

Issue #2002932 by zschmid, jastraat, vito_a | Dan Reinders: Rename Views method value_form() to valueForm().

Issue #1999322 by elvis2, alexander.ilivanov | Berdir: Remove node_save() and node_delete()/node_delete_multiple() in favor of $node->save()/$node->delete().

Issue #2001330 by juan.brein, KCarlile, zschmid, chertzog: Rename Views method add_having_expression() to addHavingExpression().

Issue #1498674 by plach, das-peter, Schnitzel, dawehner, YesCT, attiks, Berdir, Gábor Hojtsy, Soul88, Carsten Müller: Refactor node properties to multilingual.

Issue #1620010 by dawehner, ParisLiakos, plach, jibran: Move LANGUAGE constants to the Language class.

Issue #1898034 by Cottser, jenlampton, joelpittet, Shawn DeArmond, idflood, Hydra, artofeclipse, rich.yumul, chrisjlee, gnuget, c4rl, thund3rbox: block.module - Convert PHPTemplate templates to Twig.

Issue #1927608 by EclipseGc, tim.plunkett, effulgentsia: Remove the tight coupling between Block Plugins and Block Entities.

Issue #1938670 by ParisLiakos, Xano, RobLoach, pp, alexpott: Convert unicode.inc to \Drupal\Component\Utility\Unicode.

Issue #1987298 by tim.plunkett, quicksketch: Shorten directory structure and PSR-0 namespacing for plugins.

Issue #1912568 by typhonius, Berdir: Convert drupal_http_request() usage in SearchRankingTest.php to Guzzle.

Issue #1969276 by effulgentsia, tim.plunkett, EclipseGc: Refactor block plugins to make room for a BlockBase::build() implementation.

Issue #1898448 by julien, drupalway, podarok, jenlampton, steveoliver, joelpittet, jwilson3, chrisjlee, Cottser | c4rl: Convert search module to Twig.

Issue #1818556 by das-peter, plach, fago, Berdir, vijaycs85: Change notice: Convert nodes to the new Entity Field API.

Issue #1849752 by effulgentsia, Berdir, jibran, neclimdul: Abstract non-Drupal-specific parts of AnnotatedClassDiscovery into a Drupal\Component base class.