Issue #1924430 by echoz, JohnAlbin, izus, kim.pepper, LewisNyman: Add drupal.base library for base CSS styles.
Issue #1987860 by tim.plunkett: Convert taxonomy_term_add() to a new style controller.
Issue #1999434 by kim.pepper, atchijov: Use Symfony Request for system module.
Issue #2028939 by cilefen, deekayen: Clean up line wrapping in simpletest documentation and make namespaces in docs fully qualified
Issue #1988780 by pfrenssen: Fixed DrupalWebTestCase::buildXPathQuery() tries to handle backreferences in argument values.
Issue #2024833 followup by claudiu.cristea: Adopt load() and loadMultiple() on entity storage controllers.
Issue #2033447 by tim.plunkett: Remove obsolete ContainerFactoryPluginBase.
Issue #2033137 by yannickoo: Fixed New installer sidebar not properly RTL.
Issue #2029677 by afeijo: Convert BLOCK_LABEL_VISIBLE to a constant on the block interface.
Issue #2031197 by webflo, kfritsche, penyaskito: Language configuration entities should be created in English at all times.
Issue #2010086 by helga.chb, somepal, jenlampton, IshaDakota: Replace theme() with drupal_render() in system module for  theme_system_themes_page().
Issue #2032393 by effulgentsia: Limit APIs to FieldDefinitionInterface when FieldInstance isn't needed.