Issue #2575533 by leolando.tan, AlviMurtaza, LewisNyman, j2r, joaogarin: Add warning message to Seven and Bartik that they can change in the future

Issue #2541252 by HOG, finnsky, LewisNyman, nlisgo, saki007ster, alvar0hurtad0, maris.abols, pjbaert, bruvers, emma.maria, ti2m: Replace the .region-content ul/ol selector with text-formatted

Issue #2451411 by almaudoh, Shamsher_Alam, lauriii, borisson_, cilefen, davidhernandez, Cottser, Wim Leers, joelpittet: Add libraries-override to themes' *.info.yml

Issue #2566597 by Cottser, LewisNyman, mdrummond, pjbaert, jaxxed, ManuelGarcia, emma.maria, maked1sky, davidhernandez: [Mega patch] Move system *.theme.css files to Classy

This reverts commit 7cabfeee.

This reverts commit fb07e7bb.

Issue #507488 by lauriii, mdrummond, Wim Leers, Manuel Garcia, pwolanin, davidhernandez, chx, jibran, andypost, dawehner, Xano, tuutti, Gábor Hojtsy, LewisNyman, maximiliam, eiriksm, borisson_, bill richardson, Fabianx, joelpittet, Jeff Burnz, xjm, webchick, Bojhan, EclipseGc, emma.maria, tim.plunkett: Convert page elements (local tasks, actions) into blocks

Issue #2552175 by nlisgo, Wim Leers: Follow-up for #2398463: Bartik is telling CKEditor to load a CSS file that no longer exists

Issue #2470807 by LewisNyman, Dom., davidhernandez, emma.maria, lauriii, jp.stacey: Rename the default "Messages" region for all themes to "Highlighted"

Revert "Issue #2470807 by LewisNyman, Dom., davidhernandez, emma.maria, jp.stacey, lauriii: Rename the default "Messages" region for all themes to "Highlighted""

This reverts commit 249e520b.

Issue #2470807 by LewisNyman, Dom., davidhernandez, emma.maria, jp.stacey, lauriii: Rename the default "Messages" region for all themes to "Highlighted"

Issue #2389735 by lauriii, iMiksu, davidhernandez, larowlan, loopduplicate, LewisNyman, Wim Leers, dawehner, Cottser: Core and base theme CSS files in libraries override theme CSS files with the same name

Issue #2289917 by Wim Leers, mdrummond, lauriii, Manuel Garcia, emma.maria, Scionar, davidhernandez: Convert "messages" page element into blocks

Issue #1164784 by emma.maria, kattekrab, tadityar, DickJohnson, vermario, luco, Jeff Burnz, davidhernandez, David_Rothstein, webchick, Bojhan, LewisNyman, alexpott: “Triptych” term is not widely understood; add "Featured top" and "Featured bottom"

Issue #2402639 by Katiemouse, nitvirus, lakshminp, dernetzjaeger, emma.maria, gippy, kporras07, john guant, Prashant.c: Rename the footer regions in Bartik

Issue #2415855 by emma.maria: A forgotten reference to list.css in Bartik's info file is giving core a 404 error

Issue #2306407 by lauriii, penyaskito, mortendk, pakmanlh, Wim Leers, ypogue: Remove breadcrumb from page template

Issue #2064379 by tadityar, bneil: Remove ckeditor-iframe.css and load relevant Bartik CSS files for CKEditor's iframe mode

Issue #1340640 by tadityar, DickJohnson, emma.maria, Scionar:  Remove "Highlighted" region from Bartik

Issue #2235901 by alexpott, mdrummond, iMiksu, sun, Wim Leers: Remove custom theme settings from *.info.yml

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

Issue #2329501 by alexpott, mdrummond, davidhernandez | Cottser: Add classy.info.yml to core, set Classy as base theme for Bartik and Seven.

Issue #1869476 by rteijeiro, LewisNyman, lauriii, Wim Leers, mdrummond, swentel, hosef, cbiggins, larowlan, sun, EclipseGc, Gábor Hojtsy: Convert global menus (primary links, secondary links) into blocks.

Issue #2228745 by Wim Leers, sqndr, nod_, undertext: Fixed Color module doesn't look for CSS files declared in a library.

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

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

This reverts commit 9a8caf44.

Issue #2027181 by Wim Leers, seutje, Bojhan: Use a CKEditor Widget to create a stellar UX for captioning and aligning images.

Issue #1712250 by alexpott, n3or, cam8001, vijaycs85, Albert Volkman, jibran, heyrocker, chx: Convert theme settings to configuration system.