Issue #2389455 by hussainweb, AjitS, Mile23, subhojit777, tibbsa, Ayesh: Clean-up system module test members - ensure property definition and use of camelCase naming convention

Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Revert "Revert "Issue #2457653 by Gábor Hojtsy: System.site langcode is both used as a file language code and a site language code""

This reverts commit 079a52b4.

Revert "Issue #2457653 by Gábor Hojtsy: System.site langcode is both used as a file language code and a site language code"

This reverts commit 364a6e9c.

Issue #2457653 by Gábor Hojtsy: System.site langcode is both used as a file language code and a site language code

Issue #2378883 by Wim Leers, dawehner: Convert existing drupal_render() KernelTestBase tests to PHPUnit tests

Issue #2426181 by effulgentsia, mpdonadio, xjm: Add a Url::fromUserInput() wrapper method for generating URLs from user-entered paths

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

Issue #2417647 by Wim Leers, effulgentsia: Add leading slash to paths within 'user-path:' URIs, to allow 'user-path:' URIs to point to the <none> route

Issue #552478 by markcarver, sun, effulgentsia, jhedstrom, ohnobinki: Restrict "self-closing" tags to only void elements in drupal_pre_render_html_tag

Issue #2418139 by pwolanin, kgoel, dawehner, almaudoh, Wim Leers: Add a toUriString method to Url class and add a route: scheme

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

Issue #784626 by Wim Leers, Manuel Garcia, jcisio, joelpittet, Bevan, fcaspani, dcmouyard: Default all JS to the footer, allow asset libraries to force their JS to the header

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 #2379741 by Wim Leers, damiankloip: Add Renderer::getCacheableRenderArray() to encapsulate which data is needed for caching a render array and have views use it

Issue #2358981 by tadityar, tstoeckler, larowlan, mpdonadio, Devin Carlson: Provide a mechanism for dynamic library declarations

Issue #2395395 by alexpott, effulgentsia, Gábor Hojtsy: TestBase lacks a config method to be used consistently in tests

Issue #2393125 by hussainweb, droplet, mitrpaka, tarekdj: Update underscore and backbone library to latest release

Issue #2347999 by Mile23, daffie, cs_shadow, cosmicdreams: DrupalUnitTestBase is deprecated, replace with KernelTestBase

Issue #2382667 by Wim Leers, Berdir: #post_render_callback's that result from other #post_render_calback are not processed

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

Issue #2382503 by Wim Leers: Not possible to render self-contained render array while a render stack is active

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 #2324371 by lauriii, aneek, chx, joelpittet, webflo, Fabianx, rteijeiro: Fix common HTML escaped render #key values due to Twig autoescape.