Issue #1924436 by JohnAlbin, rteijeiro: Remove separate CSS_AGGREGATE_SYSTEM aggregate file and fix drupal_add_library() to aggregate CSS properly.

Issue #1657886 by Hanno: Filter 'Convert URLs into links; doesn't support multilingual web addresses.

Issue #1826252 by Jeroen, benjf, wilco: Domain language negotiation broken when a base url is configured.

Issue #2019481 by nod_: JavaScript AJAX commands object is borked: it is shared among all Drupal.ajax instances, preventing scoped overrides.

Issue #1899486 by Gábor Hojtsy, YesCT, Schnitzel, pixelite, sahain: Make link for translating content always say translate instead of translations

Issue #2009092 by smiletr: Fix up documentation for field_attach_view(), which was inaccurate for D8

Issue #1971860 by arh1, shanethehat, Fabianx: Document that Twig debug mode can cause automated tests to fail

Issue #2004408 followup by alexpott: Allow modules to alter the result of EntityListController::getOperations.

Issue #2005616 by mikeker: Views should use ['#attached']['library'] rather than ['#attached']['css'].

Issue #1861702 by echoz, rteijeiro, LewisNyman, mcjim: Add a responsive grid to the Appearance page.

Issue #1912504 by damiankloip, dawehner, amateescu: Remove _field_view_formatter_options() from Views as it duplicates FormatterPluginManager::getOptions().

Issue #1998228 by ParisLiakos, dawehner: Remove hook_menu_site_status_alter() in favor of request listeners.

Issue #1968996 by yched, swentel, xjm: Add protected saveNew() and saveUpdated() methods to Field and FieldInstance to improve code readability.

Issue #2000006 by ACF, juampy: Convert _file_test_form() to the new form interface and convert route.

Issue #1967112 followup by David_Rothstein, dawehner: HTML 5 validation breaks the cancel button in Views UI dialogs.

Issue #1933518 by ACF, pwolanin, mparker17: Convert search's system_config_form() to SystemConfigFormBase.

Issue #2009584 by rteijeiro, ry5n: Fixed Allow double underscores to pass through drupal_clean_css_identifier() as per new CSS standards.

Issue #1950634 by Wim Leers: Fatal error when creating a new text format with a text editor while JS is disabled.

Issue #2002390 by x.algorithm, nathangervais, chrisguindon, suhel.rangnekar: Rename Views method build_sort_post() to buildSortPost().