Issue #2013094 by pwieck, Cottser: Remove unnecessary template_preprocess() reference from all Twig files

Issue #1668866 by ParisLiakos, aspilicious, tim.plunkett, pdrake, g.oechsler, dawehner, Berdir, corvus_ch, damiankloip, disasm, marcingy, neclimdul: Replace drupal_goto() with RedirectResponse.

Issue #1363112 by mparker17, mgifford, tlattimore, Jacine, dcmouyard, bowersox, ry5n, ahdiaz: Simplify names of 'element-x' helper classes.

Issue #2011108 by rbayliss, chrisguindon | DmitryDrozdik: Replace drupal_container() with Drupal::service() in the overlay module.

Issue #2012836 by tim.plunkett: Replace drupal_region_class() with direct calls to drupal_html_class().

Issue #1825332 by Berdir, ParisLiakos, andypost, dawehner, jrglasgow, aspilicious: Introduce an AccountInterface to represent the current user.

Issue #1987408 by chrisjlee, jstoller, gnuget, Cottser: Overlay.module - Convert theme_ functions to Twig.

Issue #1987066 by Kevin Morse, JohnAlbin, rteijeiro, echoz, ry5n: Rename files to match CSS file naming convention.

Issue #1818570 by Berdir, effulgentsia, das-peter, andypost: Convert users to the new Entity Field API.

Issue #1969662 by swentel, amateescu, chx | yched: Provide new _update_8000_*() CRUD helpers for Field and Instance definitions.

Issue #1898436 by chrisjlee, joelpittet, gnuget, Cottser: overlay.module - Convert PHPTemplate templates to Twig.

Issue #1987426 by shanethehat, Cottser, intergalactic overlords, mr.baileys: Convert maintenance-page.tpl.php to Twig.

Issue #1938430 by shanethehat, steveoliver, Fabianx: Don't add a default theme hook class in template_preprocess().

Issue #1927608 by EclipseGc, tim.plunkett, effulgentsia: Remove the tight coupling between Block Plugins and Block Entities.

Issue #1913618 by tim.plunkett, amateescu: Convert EntityFormControllerInterface to extend FormInterface.

Issue #1959306 by jessebeach: Drupal.announce does not handle multiple messages at the same time; Improve the utility so that simultaneously calls are read.

Issue #1913086 by jessebeach, Wim Leers, mgifford, nod_: Generalize the overlay tabbing management into a utility library.

Issue #1964880 by falcon03 | jessebeach: Convert the Overlay close button from an anchor element to a button element.

Issue #1848210 by dysrama, David_Rothstein, kid_icarus, YesCT, Gábor Hojtsy: Fixed [Regression] Submitting a form in Overlay shows content + dsm() for a split second before redirecting to front-end theme.

Issue #1847084 by jessebeach, trawekp, LewisNyman, nod_, tarekdj: Fixed Vertical toolbar doesn't work with overlay (measure/track displacing elements better + provide change events for them).

Issue #967566 by Letharion, mariusz.slonina, indytechcook, adnasa, joestewart, oriol_e9g, Fabianx, tim.plunkett, valthebald, tsvenson, rbayliss, sun, xjm | DocuAnt: Several important Core User settings need to implement hook_field_extra_fields().

Issue #1838156 by ry5n, swentel, sannejanssen: Implement the two-column layout for the new create content page.

Issue #1860026 by aspilicious, David_Rothstein, katbailey, rootatwc: Remove hook_exit() for cached page requests, and decide between it and the onTerminate eventotherwise.

Issue #1871696 by tim.plunkett, xjm, sun, msonnabaum, EclipseGc: Convert block instances to configuration entities to resolve architectural issues.

Issue #1535868 by EclipseGc, tim.plunkett, xjm, Jody Lynn, sdboyer, naxoc, tizzo, effulgentsia, dawehner, disasm, beejeebus: Convert all blocks into plugins.

Issue #347988 by sun, Berdir, dawehner, Damien Tournoud, moshe weitzman: Move $user->data into own table.

Issue #1168246 by sun, mgifford, Manuel Garcia, mbrett5062, ry5n, Everett Zufelt, nod_, aspilicious, deviantintegral, tim.plunkett: Freedom For Fieldsets! Long Live The DETAILS.

Issue #1137920 by jessebeach, lewisnyman, tkoleary, Bojhan, webchick, benjifisher, nod_, sjbassett, kathryn531, effulgentsia, Everett Zufelt: fixed toolbar on small screen sizes and redesign toolbar for desktop.