Issue #2689607 by morenstrat, Ante890: Language from URL negotiator does not add request query to language switcher links

Issue #2806285 by maxocub, Gábor Hojtsy, quietone, catch: If the default language is not set, the migration log show an error

Issue #2809789 by pwolanin, dawehner: UrlGenerator fails to urlencode aliases, incorrectly encodes "system" path

Issue #2791727 by bhide.nishad, chishah92, tresti88, Chi: Wrong links in tours (eg. Language and Locale)

Issue #2795615 by GoZ: Rename LanguageUILanguageNegotiationTest::runTest to LanguageUILanguageNegotiationTest::doRunTest

Issue #2657978 by maxocub, quietone, Gábor Hojtsy, Kristen Pol, alexpott:  Variable to config: language_default [d6]

Issue #2684873 by alexpott, dawehner, Xano: ConfigurableLanguageManager::getConfigOverrideLanguage() returns NULL

Issue #2787577 by alexpott, dawehner: When tests use multiple namespaces they should do so in a coding standards compliant way

Revert "Issue #2560795 by mikeryan, phenaproxima, penyaskito, willwh, benjy: Source plugins have a hidden dependency on migrate_drupal"

This reverts commit 89815ba3.

Issue #2225775 by vasi, quietone, phenaproxima, chx, penyaskito, mikeryan, esclapes, vprocessor, steinmb, Gábor Hojtsy, Marc Angles, bwinett: Migrate Drupal 6 core node translation to Drupal 8

Issue #2560795 by mikeryan, phenaproxima, penyaskito, willwh, benjy: Source plugins have a hidden dependency on migrate_drupal

Issue #2225271 by penyaskito, quietone, svendecabooter, benjy, vasi: Migrate content type language settings from Drupal 6 & 7

Issue #2719695 by alexpott, Mile23: Fix 'Drupal.Classes.ClassDeclaration.CloseBraceAfterBody' coding standard

Issue #2716685 by Mile23: Part 2: Fix several errors in the 'Drupal.Commenting.DocComment' coding standard

Issue #2572777 by andypost, alexpott, attiks, andriyun: Fix 'Squiz.Strings.ConcatenationSpacing' coding standard

Issue #2572693 by Mile23, andriyun, andypost, attiks: Fix 'Drupal.ControlStructures.ControlSignature' coding standard

Issue #2572307 by vprocessor, attiks, andriyun, alexpott, pfrenssen: Fix 'Generic.PHP.UpperCaseConstant' coding standard

Issue #2697909 by pguillard, himanshugautam, snehi, aburrows, jhodgdon: Fix "login (noun/adjective)" vs. "log in (verb)" in comments (and logout/log out)

Issue #2456477 by Berdir, dawehner, heddn, pguillard: Convert deprecated \Drupal\simpletest\KernelTestBase tests to KernelTestBaseNG

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2686765 by sidharthap, thhafner: cacheUntilEntityChanges() is deprecated and should be replaced with addCacheableDependency()

Issue #2471689 by klopez, shashikant_chauhan, harings_rob, snehi, jhodgdon: Entity API documentation should consistently refer to handlers rather than controllers

Issue #2572125 by rodrigoaguilera, vijaycs85, swentel, Berdir, Wim Leers, tstoeckler: Content translation local tasks are not getting displayed due to caching

Issue #2672604 by saurabh.tripathi.cs: Replace deprecated usage of entity_create('taxonomy_term') and entity_create('taxonomy_vocabulary') with a direct call to Term::create() and Vocabulary::create()