Issue #2367747 by Palashvijay4O, andypost, Alienpruts, Cottser, er.pushpinderrana, gaurav.pahuja, pfrenssen, rpayanm, vadim.hirbu: Remove usage of system_rebuild_theme_data()

Issue #2289917 by Wim Leers, mdrummond, lauriii, Manuel Garcia, emma.maria, Scionar, davidhernandez: Convert "messages" page element into blocks

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

Issue #2388627 by JeroenT, filijonka, ultimateAnkit, tadityar, rpayanm, adci_contributor: Remove usages of drupal_is_front_page

Issue #2364157 by mpdonadio, dawehner, martin107, Berdir, pcambra, naveenvalecha, tim.plunkett: Replace most existing _url calls with Url objects

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 #2281645 by dawehner, andypost: Make entity annotations use link templates instead of route names

Issue #2151469 by rpayanm, lokapujya, JeroenT, alansaviolobo, Richard Damon, pflame, ianthomas_uk: Clean-up usage of deprecated list_themes() and _system_rebuild_theme_data() in favor of theme_handler service.

Issue #2030571 by calebtr, daffie, filijonka, YesCT, Thomas Brekelmans, alexpott, Mile23, tadityar, Sharique, tim.plunkett, boztek: Expand Block with methods

Issue #2170235 by Berdir, penyaskito, larowlan, alexpott, sushyl: file_private_path should be in $settings, like file_public_path

Issue #2263359 by jhodgdon: hook_help(): Top of page help sections can't link to help pages without a fatal error or checking for help module

Issue #1055150 by rootwork, Devin Carlson, yoroy, brianV, JimmyAx: Time zone description is confusing on user register form

Issue #2362227 by dawehner, mpdonadio, znerol, tim.plunkett, skipyT: Replace all instances of current_path()

git commit -m 'Issue #2377397 by Wim Leers, alexpott: Themes should use libraries, not individual stylesheets'

Issue #1833932 by lauriii, lokapujya, cilefen, Cottser, joelpittet, jenlampton, iMiksu, lanchez, ericrdb, mikispeed, Eric_A, mikemiles86: Convert theme_system_compact_link() into a #type link

Issue #2328111 by dawehner, martin107, neclimdul: Replace most instances of the DRUPAL_ROOT constant with the app.root container parameter.

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

Issue #2028109 by tim.plunkett, almaudoh, twistor, larowlan, slashrsm, Berdir, Arla, neclimdul, Cottser: Convert hook_stream_wrappers() to tagged services.

Issue #2340667 by YesCT, Pedro Lozano, alexpott, martin107: Protect Drupal\Core\Language\Language::id, and use getId().

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

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 #2343661 by larowlan, tim.plunkett | xjm: Rename l() to _l() and url() to _url(), and document replacements.

Issue #2343759 by pwolanin, larowlan, dawehner, tim.plunkett, effulgentsia, xjm, Wim Leers: Provide an API function to replace url()/l() for external urls.

Issue #2277103 by tim.plunkett, pwolanin, Wim Leers, dawehner, hotpizzas: Switch Drupal::l() and LinkGenerator to expect a Url object.

Issue #1869476 by rteijeiro, LewisNyman, lauriii, Wim Leers, mdrummond, swentel, hosef, cbiggins, larowlan, sun, EclipseGc, Gábor Hojtsy: Convert global menus (primary links, secondary links) into blocks.