Issue #1948884 follow-up by swentel, YesCT: Fix name of block schema file.
Issue #1927884 by Alan D., swentel: Always return an array from field_get_items().
Issue #1953832 by xjm, David_Rothstein: Replace 'target type' on entity reference field settings with something clearer.
Issue #1932048 follow-up by yched: Remove unnecessary constructor.
Issue #1876964 by dawehner, tim.plunkett: Improve DX when writing style plugins by adding a renderSingle function.
Issue #1952842 by tim.plunkett: Fixed Views UI still uses NOT_USED for page callbacks.
Revert "Issue #1952842 by tim.plunkett: Fixed Views UI still uses NOT_USED for page callbacks."

A little bit too much...

This reverts commit aab7094cdfc72112e10d865f9d4e2568438154ef.
Issue #1952842 by tim.plunkett: Fixed Views UI still uses NOT_USED for page callbacks.
Issue #1945326 by tim.plunkett: Rename \Drupal\system\Tests\System\SystemConfigFormBase to \Drupal\system\Tests\System\SystemConfigFormTestBase.
Issue #1932336 by damiankloip: Use override free configuration context for SystemConfigFormBase.
Issue #1956434 by Berdir, amateescu: Fixed Can't edit nodes with entity reference fields.
Issue #1930274 by rootatwc, Berdir: Convert aggregator processors and parsers to plugins.
Issue #1945348 by damiankloip: Call decorated storage methods in ViewsUI explicitly.
Issue #1955972 by BTMash: Remove BTMash from MAINTAINERS.txt.
Issue #1957314 by rootatwc: Add rootatwc as aggregator maintainer in MAINTAINERS.txt.
Issue #1958560 by alexpott: Add alexpott to branch maintainers for Drupal 8.
git commit -m Issue
Issue #1898448 by julien, drupalway, podarok, jenlampton, steveoliver, joelpittet, jwilson3, chrisjlee, Cottser | c4rl: Convert search module to Twig.
This reverts commit 80e373fa92148550e387b9873ae7cfc5b2bfc747
Issue #1925738 by tim.plunkett: Convert language's system_config_form() to SystemConfigFormBase.