Issue #1939064 by joelpittet, pwieck, farrington, mark.labrecque, Cottser, InternetDevels, mdrummond, drupalninja99, BarisW, jenlampton: Convert theme_links() to Twig.

Issue #2152207 by steveoliver, joelpittet, gnuget, idflood, hussainweb, shanethehat, jenlampton, kpa, AnythonyR, EVIIILJ, kgoel, Cottser, dsdeiz, hanpersand: Convert theme_details() to Twig

Issue #1939062 by steveoliver, mdrummond, jenlampton, hussainweb, Cottser, joelpittet, jerdavis, ekl1773, dale42, drupalninja99, gabesullice, c4rl: Convert theme_item_list() to Twig.

Issue #2177655 by chakrapani, InternetDevels, martin107 | jessebeach: Replace theme() with drupal_render() in install.core.inc.

Issue #2176105 followup by sun: Installer catches exceptions and manually re-prints them; does not use error/exception handler.

Issue #2177653 by jessebeach, joelpittet, InternetDevels: Replace theme() with drupal_render() in form.inc.

Issue #2185831 by tim.plunkett: Split up ParamConverterManager and stop throwing NotFoundHttpException.

Issue #2152229 by steveoliver, rteijeiro, joelpittet, JeroenT, InternetDevels, michamilz, burgerboydaddy, hussainweb, shanethehat, jenlampton, kpa, AnythonyR, EVIIILJ, kgoel, Cottser, dsdeiz, hanpersand: Convert theme_textarea() to Twig

Issue #2152213 by steveoliver, joelpittet, hussainweb, shanethehat, jenlampton, kpa, AnythonyR, EVIIILJ, kgoel, Cottser, dsdeiz, hanpersand: Convert theme_form_element() to Twig

Issue #2168011 by xjm, jessebeach, Damien Tournoud, znerol, Xano: Remove all 7.x to 8.x update hooks and disallow updates from the previous major version.

Issue #2176105 by sun: Installer catches exceptions and manually re-prints them; does not use error/exception handler.

Issue #2164827 by Berdir, Xano, tim.plunkett: Rename the entityInfo() and entityType() methods on EntityInterface and EntityStorageControllerInterface.

Issue #2167039 by likin, dawehner, Wim Leers, tstoeckler, vijaycs85: Regression: page cache tags broken, also: some routes incorrectly use _controller -> No page object in template variables -> Fatal in seven_preprocess_page().

Issue #2047633 by pwolanin, dawehner, kim.pepper, Xano, amateescu, tim.plunkett: Move definition of menu links to hook_menu_link_defaults(), decouple key name from path, and make 'parent' explicit.

Issue #2167109 by Berdir, sun, alexpott, ACF, acrollet, adamdicarlo, Albert Volkman, andreiashu, andyceo, andypost, anenkov, aspilicious, barbun, beejeebus, boombatower, cam8001, chriscalip, chx, cosmicdreams, dagmar, damiankloip, dawehner, deviance, disasm, dixon_, dstol, ebrowet, Gábor Hojtsy, heyrocker, Hydra, ianthomas_uk, japicoder, jcisio, jibran, julien, justafish, jvns, KarenS, kbasarab, kim.pepper, larowlan, Lars Toomre, leschekfm, Letharion, LinL, lirantal, Lukas von Blarer, marcingy, Mike Wacker, mrf, mtift, mtunay, n3or, nadavoid, nick_schuch, Niklas Fiekas, ParisLiakos, pcambra, penyaskito, pfrenssen, plopesc, Pol, Rok Žlender, rvilar, swentel, tim.plunkett, tobiasb, tsvenson, typhonius, vasi1186, vijaycs85, wamilton, webchick, webflo, wizonesolutions, xjm, yched, YesCT, znerol: Remove Variable subsystem.

Issue #1165694 by pillarsdotnet, Sutharsan, droplet: Remove default nomask from file_scan_directory().

This reverts commit f2769f4d.

Issue #2164367 by alexpott, tim.plunkett, dawehner: Rebuild router as few times as possible per request.

Issue #2164025 by skipyT, pwolanin: Improve security of session ID against DB exposure or SQL injection.

Issue #2169447 by damiankloip, sun, longwave: DX: Supply CacheBackendInterface::CACHE_PERMANENT as Cache::PERMANENT.

Issue #2152231 by rteijeiro, steveoliver, joelpittet, hussainweb, shanethehat, jenlampton, kpa, AnythonyR, EVIIILJ, kgoel, Cottser, dsdeiz, hanpersand: Convert theme_vertical_tabs() to Twig