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

Issue #1965208 by amateescu, Berdir: Convert TaxonomyTermReferenceItem to extend EntityReferenceItem.

Issue #1981316 by aspilicious, andypost, pcambra, swentel: Drop procedural usage of fields in [f-l] modules.

Issue #1947536 by andypost, donquixote, larowlan, splatio, kim.pepper, alexpott, Crell, tim.plunkett: Convert drupal_get_breadcrumb() and drupal_set_breadcrumb() to a service.

Issue #1363112 by mparker17, mgifford, tlattimore, Jacine, dcmouyard, bowersox, ry5n, ahdiaz: Simplify names of 'element-x' helper classes.

Issue #1999328 by DmitryDrozdik, annikaC, jeroen12345, andypost: Remove comment_save() and comment_delete()/comment_delete_multiple() in favor of $comment->save()/$comment->delete().

Issue #1987066 by Kevin Morse, JohnAlbin, rteijeiro, echoz, ry5n: Rename files to match CSS file naming convention.

Issue #1888424 by katbailey, steveoliver, twistor, beejeebus, effulgentsia: Change notice: Make Drupal's URL generation logic available to HttpKernel, and minimize code repetition/divergence.

Issue #1204658 by kbasarab, Berdir, tim.plunkett, webchick: Always use query metadata to specify the node access base table.

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 #1898418 by Cottser, shanethehat, c4rl, joelpittet, disasm, Floydm, jenlampton: forum.module - Convert PHPTemplate templates to Twig.

Issue #1957888 by ParisLiakos, Berdir: Fixed Exception when a field is empty on programmatic creation.

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

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

Issue #1913618 by tim.plunkett, amateescu: Convert EntityFormControllerInterface to extend FormInterface.

Issue #1818560 by Berdir, fago, Wim Leers, jessebeach, dawehner, YesCT: Convert taxonomy entities to the new Entity Field API.

Issue #1938932 by duellj, andypost, tim.plunkett: Remove taxonomy_overview_terms() and taxonomy_overview_vocabularies()  theme functions in favour of table #type.

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

Issue #1946414 by larowlan | mtift: Convert confirm_form() in forum.admin.inc to the new form interface.

Issue #1209226 by catch, Berdir, miro_dietiker, beejeebus, dagmar: Fixed Avoid slow query for path alias whitelists.

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.

Issue #1591806 by tim.plunkett, ryanissamson, jenlampton, Risse, psynaptic, Gábor Hojtsy, kmcculloch, pakmanlh, Rob Loach: Change block 'subject' so that it's called (admin_)label like everything else on the theme layer.

Issue #1864066 by sun, andypost, tim.plunkett: Simplify hook_menu_local_tasks() and MENU_DEFAULT_LOCAL_TASK usage.