Issue #2284111 by alexpott, Berdir, damiankloip: Fixed Exceptions caught and printed from index.php should not return a 200 status code.

Issue #2278541 by tim.plunkett, kim.pepper, Bojhan, EclipseGc: Refactor block visibility to use condition plugins.

Issue #2039449 by joshi.rohit100, joachim, lokapujya, Jalandhar, paulh, yaworsk: Fix docs for assertField methods in WebTestBase to describe how to skip value checking

Issue #2279617 by thedavidmeister, mgifford: Fixed _filter_url_trim() should use Unicode::truncate().

Issue #2216557 by jhodgdon, mongolito404, Berdir: Fill in @defgroup/topic docs for Testing overview.

Issue #2270815 by vijaycs85, Gábor Hojtsy, nvinayvinay: Make schema testing code available as generic API.

Issue #2246661 by ivanjaros: Some templates are missing 'Default theme implementation ..' statement.

Issue #2256679 by alexpott, tim.plunkett: Fixed Use config schema to determine which config entity properties to export regardless of whether they are public or protected.

Issue #2247779 by Wim Leers, larowlan, dawehner: Allow #pre_render, #post_render and #post_render_cache callbacks to be service methods.

Issue #2275877 by Mixologic, duellj, Les Lim, Xano, David Strauss: Replace master/slave terminology with primary/replica.

Issue #1914914 by purdy_nc, meba, chx, heyrocker: Add to docs of file_scan_directory to discuss excluding config

Issue #2281419 by t0xicCode, joshi.rohit100, SiliconMind: Fix up docs for FieldItemInterface methods

Issue #2260043 by t0xicCode, amitgoyal: Remove lingering references to obsolete field crud and attach topics and functions

Issue #2243439 by amitgoyal, jonreid, mark.labrecque, mpv, pwolanin, scor, cilefen, sun: Fix up docs about config file/database locations in settings.php and READMEs in directories

Issue #2267159 by juampy, xjm, alexpott: Remove nonexistent parameter from WebTestBase::assertNoLink docs

Issue #1912610 by amitgoyal, BryanCGreen24, lokapujya, Rajendar Reddy, echoz, barraponto, LewisNyman, pixelwhip: Rename layout classes to follow the layout style naming convention.

Issue #2228763 by larowlan, alexpott, martin107, jessebeach, xjm: Create a comment-type config entity and use that as comment bundles, require selection in field settings form.

Issue #1939092 by mgifford, dbazuin, jenlampton, azinoman, pwieck, Cottser, joelpittet, larowlan: Convert theme_mark() to Twig.

Issue #1898070 by benjifisher, jjcarrion, LinL, idflood, joelpittet, oshelach, tlattimore, Les Lim, sergey.semashko, jesse.d, bdgreen, jenlampton, Cottser, duellj, artofeclipse, vlad.dancer, steveoliver, EVIIILJ, c4rl, elv, OpenChimp: File.module - Convert theme_ functions to Twig.

Issue #2151821 by joelpittet, JacobSanford, jjcarrion, rteijeiro, c4rl, IshaDakota, pplantinga, gnuget, longwave, jeanfei, sbudker1: Convert theme_system_config_form() to Twig

Issue #1898420 by mondrake, joelpittet, InternetDevels, claudiu.cristea, c4rl, DamienMcKenna, Albert Volkman, shanethehat, thedavidmeister: Image.module - Convert theme_ functions to Twig.

Issue #2250325 by jhodgdon, azinck, splatio: Fixed Route book.render (path /book) does not seem to work.

Issue #2052473 by ricky.middaugh, lokapujya, Jalandhar, mgifford, jessebeach, BarisW, falcon03: Add aria-label or aria-describedby attributes to all <nav> elements.

Issue #2080343 by connork, izus, rahul.shinde, lokapujya | mrsinguyen: Remove Unused local variables from system module.