Issue #2534020 by phenaproxima: Move module-specific migration support into the menu_link_content module

Issue #2540538 by znerol: Behavior of testErrorContainer() and testExceptionContainer() is unpredictable

Issue #2490228 by damiankloip, almaudoh, martin107, clemens.tolboom, -enzo-, znerol, dawehner: Add Authentication Collector

Issue #2078803 by Wim Leers, aspilicious, wmortada, Sumit kumar, mrjmd, John Cook: Change contextual links background color to match the styleguide

Issue #2501481 by Cottser, davidhernandez, kfriend, alimac, YesCT, lauriii, tim.plunkett, cilefen, lbainbridge, porchlight: form_select_options() is a theme function in disguise and should not use SafeMarkup::set

Issue #2541084 by martin107, dawehner: ViewPageController does not need $storage nor $executableFactory

Issue #2507093 by claudiu.cristea, catch, timmillwood, dawehner: Don't calculate the theme_token for ajaxPageState unless necessary

Issue #2498163 by Arla, jeni_dc, nathanlawson91, MrPaulDriver, LewisNyman: Legend overlap with radios/checkboxes inside fieldset/fieldgroup

Issue #2539860 by jeni_dc, LewisNyman: Add a class to field that contain user-generated formatted text

Issue #2516842 by er.pushpinderrana, thejacer87, jhodgdon: UPGRADE.txt should explain where to find release notes

Issue #2382513 by mikeker, chris_hall_hu_cheng, joachim, joelpittet, alexpott, YesCT, quietone, mikeker, Jeroen, joris_lucius, katy5289, sivaji@knackforge.com: Regression fix: allow Drupal 8 to work without Apache mod_rewrite

Issue #2529514 by dawehner, Fabianx, Wim Leers: Replace system.filter::protocols with container parameters

Issue #2539300 by cilefen, tim.plunkett: Remove SafeMarkup::set in \Drupal\Tests\Core\Form\FormCacheTest::testSetCacheWithSafeStrings()