Issue #1067408 by alexpott, Jalandhar, jessebeach, Désiré, neetu morwani, dawehner, sun: Themes do not have an installation status.
Issue #2198429 by alexpott: Make deleted fields work with config synch.
Issue #2225955 by tim.plunkett, Berdir: Improve the DX of writing entity storage classes.
Issue #2083547 by donquixote: Docblock and code style improvements in DrupalKernel.

This is in preparation for the switch of module-provided classes from PSR-0 to PSR-4.
Issue #2083547 by donquixote: Implement PSR-4 for module-provided class files.

This affects class loading, plugin discovery and test discovery.

PSR-0 is still supported, and no module class files are moved yet.
Issue #2083547 by donquixote: Introduce core/scripts/switch-psr4.sh, to move module-provided class files to their new PSR-4 location.
Issue #2083547 by donquixote: Move class files in core/modules/shortcut to their new PSR-4 location, to verify that PSR-4 actually works.
Issue #2246557 by dawehner: Missing schema for entity area plugin.
Issue #2056173 by philipz, Sam152 | tim.plunkett: Regression: Two-column layout is broken by vertical toolbar.
Issue #2194823 by znerol, YesCT, dawehner: Ensure that all content/page routes have an _title.
Issue #2228721 by amateescu, drunken monkey: TypedData doesn't support config entity types; flag errors if you try.
Issue #2245783 by tim.plunkett: Regression: Help blocks display on 403/404 page.
Issue #2246637 by ivanjaros: Status-report.html.twig is missing @file tag.
Issue #2245249 by tim.plunkett: Convert installer forms to FormInterface.
Issue #2245185 by tim.plunkett: Fix invalid @covers usage.
Issue #1366020 by pwolanin, dawehner, rcaracaus, jhodgdon | tstoeckler: Overhaul SearchQuery; make search redirects use GET query params for keywords.
Issue #1574560 by andypost, Rajendar Reddy: Update jQuery Form Plugin to the latest in the git repository.
Issue #1842326 by c4rl, sun, joelpittet, pakmanlh, jjcarrion | jenlampton: Merge _theme_table_cell() into theme_table().
Issue #2236089 by cs_shadow, sriharsha.uppuluri: theme_settings schema duplicates the label Shortcut icon settings where it doesn't make sense.
Issue #2241549 by neclimdul: Remove registerContainerConfiguration() cruft from DrupalKernel.