Issue #2166065 by alexpott, mtift: Replace config_install_default_config with ConfigInstaller service.

Issue #2099105 by Berdir, andypost, amateescu, larowlan: Clean-up render cache when permission changes.

Issue #1823494 by Berdir, sun, Jānis Bebrītis: Field API assumes serial/integer entity IDs, but the entity system does not.

Issue #1231710 by Hydra, dcam, kathyh, klausi, mlncn: Field exceptions should return the name of the field that has exceptions.

Issue #2098119 by beejeebus, alexpott, chx: Replace config context system with baked-in locale support and single-event based overrides.

Issue #2042807 by tim.plunkett, pwolanin, ianthomas_uk, jhodgdon: Convert search plugins to use a ConfigEntity and a PluginBag.

This reverts commit cb41c8cf.

Issue #2163231 by jessebeach: RTL styling was jumbled while fixing the disappearing Toolbar tray box-shadow issue.

Issue #2162685 by clemens.tolboom: CKEditor's Internal::generateFormatTagsSetting() should call check_markup() with caching enabled.

Issue #1963474 by infojunkie, widukind, Cottser, joelpittet, hussainweb, nod_: Ckeditor.module - Convert theme_ functions to Twig.

Issue #1898464 by jenlampton, Cottser, joelpittet, steveoliver, Dustin Currie, shanethehat, cafuego, mr.baileys, adnen: toolbar.module - Convert theme_ functions to Twig.

Issue #1987854 by splatio, disasm, kim.pepper, vijaycs85, sidharthap, dawehner: Convert system_themes_page() to a new style controller.

Issue #2168101 by xjm: UpdateModuleHandler does not follow coding standards for switch statements and is hard to read.

Issue #2167469 by pwolanin: Test EntityViewControllerTest has the wrong descriptive text in getInfo().

Issue #2042739 by jhedstrom, bdone, dawehner, tim.plunkett: Convert system module's ControllerResolverTest to phpunit.

Issue #2159755 by damiankloip: Unit test the Drupal\serialization\EntityResolver\ChainEntityResolver class.

Issue #2041793 by mortendk, rteijeiro, LewisNyman, magnify, axe312, zorp, mdrummond: Install-page.html.twig markup and CSS.

Issue #2168113 by penyaskito, jessebeach, catch: Add leading underscore and other discouragement to drupal_add_css() and drupal_add_js().