Issue #2197877 by kirby14: Remove empty views.display_extender.schema.yml file.
Issue #2191897 by damiankloip: Unit test the Drupal\serialization\Normalizer\EntityNormalizer class.
Issue #2151093 by Cottser, quietone, joelpittet, InternetDevels: Convert theme_admin_block_content() to Twig.
Issue #2194061 by jibran: Fix documentation in ConfigSync.
Issue #2191273 by mfernea: Fix Feed typehints in aggregator module.
Issue #2196379 by longwave: Add new simpletest directory location in example.gitignore file .
Issue #1919338 by catch, swentel, bblake, EllaTheHarpy, Cottser: Select widget (from the options module) prone to double encoding.