Issue #1836204 by sun, dawehner: Fixed Random test failure in Drupal\system\Tests\Menu\BreadcrumbTest.

Issue #891112 by Berdir, sun, Amitaibu, siharris, Cottser: Replace theme_item_list()'s 'data' items with render elements.

Issue #1751174 by zuuperman, yched: Convert file and image module widgets / formatters to Plugin system.

Issue #1763974 follow-up by neclimdul, sun: Put in temporary entity info hook shiv until conversions are complete.

Issue #1801570 by effulgentsia, klausi, Crell, disasm: DX: Replace hook_route_info() with YAML files and RouteBuildEvent.

Revert "Issue #1801570 by effulgentsia, klausi, Crell: DX: Replace hook_route_info() with YAML files and RouteBuildEvent. This unintentionally broke REST module tests."

This reverts commit 7bf7eb83.

Issue #1801570 by effulgentsia, klausi, Crell: DX: Replace hook_route_info() with YAML files and RouteBuildEvent.

Issue #1817044 by sdboyer, effulgentsia, tim.plunkett, Gábor Hojtsy, yched: Implement Display, a type of config for use by layouts, et. all.

Issue #1790964 by anzi31, dawehner, xjm, tim.plunkett: Document that ViewExecutable::preview() doesn't call ViewExecutable::access().

Issue #1825466 by justafish, sun, alexpott: Allow NestedArray::mergeDeepArray() to preserve integer keys for the purpose of merging config data.

Issue #1829338 by larowlan, falcon03: Fixed comment tab settings aren't announced in comment tab title.

Issue #1739986 by pwolanin, moshe weitzman: Fixed fallback in drupal_get_hash_salt(), move it to bootstrap.inc, use instead of $GLOBALS['drupal_hash_salt()'].

Issue #1300920 by salvis, DamienMcKenna, mkadin, gumanist, Niklas Fiekas, greggles: Fixed The [node:summary] token does not output anything for body fields without a manual summary.

Issue #1488630 by Berdir: Fixed Who's online block doesn't work with swappable session backends and lazy session creation.