Issue #2167623 by danilenko_dn, sidharthap, Nitesh Sethia, krishnan.n, aitiba, alexpott, ashwinikumar, Barrett, damiankloip, deepakaryan1988, foxtrotcharlie, ianthomas_uk, neetu morwani, nonsie, piyuesh23, Sharique, sivaji, sushantpaste, swentel, vijaycs85, YesCT: Add test for all default configuration to ensure schema exists and is correct.

Issue #2184315 by Wim Leers: Move filter_get_filter_types_by_format() and filter_get_html_restrictions_by_format() onto FilterFormatInterface.

Issue #2056445 by alexpott, Marcus Maihoff, rahul.shinde: Ensure that all config can not be deleted using the config importer.

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 #1913510 by erich_s, jibran, scresante, nod_, mitron: Core Javascript Files Not Using Standard Indentation.

Issue #2181293 by pwolanin, dawehner: AccessManager::checkNamedRoute() is not passing all route defaults (or building a complete route request).

Issue #2175739 by alexpott: Actually test node_access_test_secret_catalan and clean up deprecated code in NodeAccessLanguageTest.

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

Issue #2181811 by alexpott: System info can become inconsistent if hook_system_info_alter() makes a module required.

Issue #2172941 by vijaycs85, damiankloip: Endless looping on Config::castValue() for undefined config data type.

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 #2102477 by alexpott: Convert remainder of language negotiation settings to configuration system.

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

Issue #2151101 by joelpittet, c4rl, IshaDakota, pplantinga, gnuget, longwave, jeanfei, sbudker1: Convert theme_status_report() to Twig

Oops. Wrong commit credit.

This reverts commit 6d5899ec.

Issue #2176131 by sun: Database configuration form in installer still uses 'db_prefix' instead of 'prefix'.

Issue #2177667 by InternetDevels | jessebeach: Replace theme() with drupal_render() in locale.bulk.inc.