Issue #1785086 by Jose Reyero, Gábor Hojtsy, catch, loganfsmyth, nedjo, stella: Added Introduce a generic API for interface translation strings.

Issue #1642526 by andypost, Berdir, dixon_: Add upgrade path from for generating UUIDs for all core entities.

Issue #1805776 by psynaptic, Eric_A, rbayliss: Fixed Fatal error: Class 'Drupal\Core\Template\ArrayIterator' not found in core/lib/Drupal/Core/Template/Attribute.php.

Issue #1642062 by tim.plunkett, xjm, chx, merlinofchaos, damiankloip, dawehner, Berdir, aspilicious, Fabianx: Add TempStore for persistent, limited-term storage of non-cache data.

Issue #742344 by sun, pillarsdotnet, tarmstrong, neilnz, wamilton, lucascaro: Allow forms to set custom validation error messages on required fields.

Issue #1742438 by larowlan, Christian Biggins, kim.pepper, Everett Zufelt: Fixed Vertical tabs header and container rendered even when no vertical tabs.

Issue #1706878 by tim.plunkett, lazysoundsystem: Add WebTestBase::assertThemeOutput() to allow modules to test theme function output.

Issue #1760530 by jenlampton, Albert Volkman, crazyrohila, Risse, justafish, Fabianx: Move all template files provided by core modules and themes into a 'templates' directory inside that module directory.

Issue #1788588 by pcambra | cosmicdreams: Fixed Remove unused variables from SimpleTest's WebTestBase.

Issue #1464554 by aspilicious, jhedstrom, sun, alexpott, disasm | heyrocker: Upgrade path for image style configuration.

Issue #1802834 by tim.plunkett: Added Use #type => operations for EntityListController::buildOperations().

Issue #1439462 by nod_, Jelle_S: Drop our custom $.support.positionFixed and use jQuery's $.support.fixedPosition.

Issue #1326618 by Albert Volkman, ykhadilkar, oriol_e9g, daniel_j, xenophyle: API docs cleanup for locale module

Issue #1326664 by Lars Toomre, Albert Volkman, sven.lauer, tim.plunkett: API docs cleanup for parts of system module and other files

Issue #1802844 by antojose: Fixed 'have to' repeated twice as 'have to have to' in the comment for the function hook_module_implements_alter() in system.api.php.