Issue #2152217 by joelpittet, mgifford, vijaycs85, jjcarrion, sun: Remove theme_form_required_marker() from the theme system - use CSS instead.

Issue #2233787 by alexpott, xjm | tim.plunkett: Move default configuration into extension/config/install to clarify its purpose.

Issue #1921044 by pakmanlh, Manuel Garcia, rteijeiro, dasjo, aboros, sqndr, LewisNyman: Align the styling of tool tips to be more consistent with Seven.

Issue #2227869 by joelpittet: Remove magic printing from Attribute class to make Twig 'without' filter work for attributes.

Issue #2218655 by sun, effulgentsia, jessebeach: Core expects $theme.settings default config file to exist.

Issue #1533104 by visabhishek, bryanbraun, TravisCarden, majoely | NROTC_Webmaster: Make bartik theme pass Coder Review.

Issue #2089433 by ianthomas_uk, grom358, herom, thedavidmeister, visabhishek, longwave, Sweetchuck: Remove uses of deprecated XSS filter functions.

Revert "Issue #2218039 by sun, dawehner: Render the maintenance/install page like any other HTML page."

Broke update.php.

This reverts commit 10b03890.

Revert "Issue #1813186 by nod_: Integrate scripts/stylesheets from info/layout files with libraries."

This reverts commit 9a8caf44.

Broke Bartik, still needs discussion.

This reverts commit 5a8a34e8.

Issue #2056879 by martin107, Outi, ioskevich, Cottser: Improve twig_* vars DOCs in settings.php and make Twig debug markup require a cache clear.

Issue #2226185 by galooph, filijonka, Cottser: Remove @ingroup themeable from core theme Twig template docblocks.

Issue #2169765 by philipz, Sutharsan, ckrina, c_lehel, LewisNyman: Redesign update.php to be more consistent with the installation process.

Revert "Issue #2169765 by philipz, Sutharsan, ckrina, c_lehel, LewisNyman: Redesign update.php to be more consistent with the installation process."

This reverts commit 728aad1d.

Issue #2183005 by InternetDevels, Outi, jessebeach: Style inlined .caption elements (figure) - Bartik edition.

Issue #2169765 by philipz, Sutharsan, ckrina, c_lehel, LewisNyman: Redesign update.php to be more consistent with the installation process.

Issue #1987398 by Nigel_S, Tim Bozeman, InternetDevels, adsw12, joelpittet, Cottser, mdrummond, dsayswhat, jerdavis, rteijeiro, LewisNyman, Rumato, gnuget: Field.module - Convert theme_ functions to Twig.

Issue #2212309 by joelpittet: Drupal\Core\Template and twig.engine docs, coding standards, and unused code cleanup.

Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, alexpott, tstoeckler, Xano, tim.plunkett, BassistJimmyJam | beejeebus: Make modules and installation profiles only require .info.yml files.

Revert "Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, tstoeckler, Xano, tim.plunkett, BassistJimmyJam: Make modules and installation profiles only require .info.yml files."

This reverts commit b4c561d0.

Issue #340723 by ParisLiakos, sun, Berdir, glennpratt, Cottser, swentel, tstoeckler, Xano, tim.plunkett, BassistJimmyJam: Make modules and installation profiles only require .info.yml files.

Issue #2210197 by sun, longwave, Sutharsan: Remove public access to Extension::$type, ::$name, ::$filename.