Issue #2239003 by Wim Leers, dawehner | effulgentsia: Remove the '_http_statuscode' request attribute.

This reverts commit 0faa5ce3.

Issue #2183075 by valderama, dinarcon, er.pushpinderrana, amitgoyal, umar-ahmad: Tidy up css.gzip and js.gzip configuration.

Issue #2361681 by Wim Leers: drupal_render(): invert second argument ($is_recursive_call -> $is_root_call) => more strict, better DX/TX.

Issue #2294571 by znerol, effulgentsia: Redirect anonymous users to login page from an exception listener instead of in MaintenanceModeSubscriber and restrict access to the my-account link to authenticated users.

Issue #2282519 by alexpott, cilefen: Fixed Add content dependency information to configuration entities.

Issue #1956698 by Gábor Hojtsy, xjm, alexpott, damiankloip, mgifford: Prevent access to YAML files using .htaccess and web.config.

Issue #2349651 by larowlan, yannisc: Fixed Default contact form does not send email as email recipient is not set during the installation.

Issue #2316561 by jmolivas | YesCT: Type hint hooks with interface: ConfigurableLanguageInterface instead of LanguageEntity/ConfigurableLanguage.

Issue #2359449 by Jose Reyero: Fixed TypedData calls onChange() parent's method that is not part of the interface.

Issue #2278583 by nlisgo, Berdir, joshi.rohit100 | Fabianx: Fixed field_has_data looks at current data instead of revisioning data: this can lead to data loss.

Issue #2362123 by Wim Leers: Drupal_page_header() and drupal_send_headers() are dead code: already deprecated, zero uses remain: remove.

Issue #1419298 by ryanissamson, zaporylie, ohthehugemanatee, ramlev, droplet, Albert Volkman, NROTC_Webmaster, pmitchell, pillarsdotnet: Remove all trailing whitespace from Drupal core files.

Issue #2288793 by YesCT, jamesdixon, xq1003, fran seva, Les Lim: Add missing and fix some types in core docblocks and add some typehinting for locale module.

Issue #1813488 by babruix, Ivan Zugec, quietone, ngwebs, legolasbo | amontero: Add descriptions to clarify "administer users" and "administer user settings" permissions.

Issue #2065485 by tim.plunkett, Xano: Document that PluginFormInterface should use #process to solve nesting issues.

Issue #2329763 by lauriii, Jens-0, Cottser, Sutharsan: Move links classes from preprocess to templates.

Issue #2329767 by lauriii, alexpott, Cottser, sqndr: Move table classes from preprocess to templates.

Issue #2358333 by mikey_p: Fixed ConfigManager should use interface for translation manager type hint.

Issue #2359005 by alexpott: Fixed LocalTaskManagerTest only works because we mock a non existing method.