git commit -m 'Issue #2377397 by Wim Leers, alexpott: Themes should use libraries, not individual stylesheets'

Issue #2328111 by dawehner, martin107, neclimdul: Replace most instances of the DRUPAL_ROOT constant with the app.root container parameter.

Issue #2028053 by vegantriathlete, franxo, InternetDevels, thamas, rootwork, LewisNyman: Add typographic styles, components, and utility classes.

Issue #2337379 by skippednote, BarisW, derjochenmeyer, herom, ChandeepKhosa, kiliweb, sqndr, Palashvijay4 | LewisNyman: Rename 'branding' to 'content-header'.

Issue #2213583 by lauriii, sqndr, Crisz, herom, jamesquinton, esod, Rajendar Reddy, zserno, er.pushpinderrana, cs_shadow, amitgoyal | JayeshSolanki: Fixed Misaligned Icons in Drupal 8.x.

Issue #2270323 by sun, dawehner, neclimdul: Remove DRUPAL_ROOT constant redefinitions from unit tests.

Issue #2271251 by ParisLiakos, undertext, JeroenT, StevenPatz, tim.plunkett: Remove usages of watchdog() from non-form and non-controllers.

Issue #2307419 by Wim Leers: AssetCollectionOptimizerInterface should allow listing and deleting all aggregates (optimized collection assets).

Issue #2033211 by jwilson3, LewisNyman, sqndr, tim.plunkett, JamesLefrère | yannickoo: Move Seven CSS files into css directory.

Revert "Issue #2033211 by LewisNyman, tim.plunkett, JamesLefrère | yannickoo: Move Seven CSS files into css directory."

This reverts commit 16e60c42.

Issue #2033211 by LewisNyman, tim.plunkett, JamesLefrère | yannickoo: Move Seven CSS files into css directory.

Issue #697760 by sun: Replace getInfo() in tests with native phpDoc + annotations (following PHPUnit).

Issue #2017257 by jason.bell, dead_arm, alexrayu, philipz, idebr, rteijeiro, emma.maria, frankbaele, LewisNyman: Create generic layout classes.

Issue #1989470 by LewisNyman, aboros, philipz, mgifford, rteijeiro, dimaro, Bès, klonos, emma.maria: Dropbutton style update for Seven.

Issue #1067408 by alexpott, Jalandhar, jessebeach, Désiré, neetu morwani, dawehner, sun: Themes do not have an installation status.

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

Issue #2228921 by sun: Consolidate system.module + system.theme + system.theme.disabled into core.extension config.

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 #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.

Revert "Issue #2210197 by sun, longwave: Remove public access to Extension::$type, ::$name, ::$filename." Broke 'drush en simpletest' on testbots

This reverts commit 2c51074d.

Issue #2187717 by sun, dawehner: Remove code duplication in system_list() and ThemeHandler::rebuildThemeData().

This reverts commit ae8be3cc.

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

Issue #641734 by echoz, LewisNyman, davidtrainer, Cottser, falkendk, rteijeiro: Separate generic html elements' style into seven.base.css.