Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Revert "Issue #2656278 by miteshmap, walangitan, empesan, ejb503, manmohandream, vaidehi bapat, gadaniels72, luca_cracco, swentel, malaimo29001, nileema.jadhav, sidharthap: Convert "Limit allowed HTML tags" input field to a textarea"

This reverts commit 53766025.

Issue #2656278 by miteshmap, walangitan, empesan, ejb503, manmohandream, vaidehi bapat, gadaniels72, luca_cracco, swentel, malaimo29001, nileema.jadhav, sidharthap: Convert "Limit allowed HTML tags" input field to a textarea

Issue #2579471 by walangitan, droplet, biguzis, thorandre, swentel: Allow more chars in "Limit allowed HTML tags" filter

Issue #2596083 by Wim Leers, lokapujya, jamin_melville: Allowed attribute 'class' not respected in CKEditor: ACF strips it

Issue #2579357 by pwolanin: Fix text for "Limit allowed HTML tags" filter to also indicate it restricts HTML attributes

Issue #2549077 by pwolanin, Wim Leers, phenaproxima, lauriii: Allow the "Limit allowed HTML tags" filter to also restrict HTML attributes, and only allow a small whitelist of attributes by default

Issue #2570355 by Sutharsan, stefan.r, kgoel, josephdpurcell, joelpittet, justAChris, dawehner, pfrenssen, pwolanin, David_Rothstein, catch: Replace remaining !placeholder and @placeholder with :placeholder for URLs

Issue #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk, olli: Remove all usages SafeMarkup::checkPlain() from render arrays

Revert "Issue #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk: Remove all usages SafeMarkup::checkPlain() from render arrays"

This reverts commit 31007609.

Issue #2560641 by alexpott, lauriii, Xano, borisson_, ianthomas_uk: Remove all usages SafeMarkup::checkPlain() from render arrays

Issue #2504529 by joelpittet, alexpott, catch: SafeMarkup does not escape some filter tips - remove SafeMarkup usage from FilterHtml

Issue #2521906 by mErilainen, LewisNyman, Bojhan, eliza411, ivanstegic, lunk_rat, nickrosencrans, stpaultim, Mark LaCroix, webchick: Add default configuration to support h2-h6 level headings

Issue #2346209 by keopx, Zekvyrin, subhojit777, cburschka, pguillard, dimaro, realityloop, m4olivei, joelpittet, rteijeiro, idebr: /filter/tips improperly escaped

Issue #2457887 by prateekMehta, stefan.r, rpayanm, alexpott: Use Utility\SafeMarkup class instead of Utility\String for placeholder(), checkPlain(),format() functions

Issue #2089331 by grom358 | thedavidmeister: [meta] Replace calls to check_plain() with Drupal\Component\Utility\String::checkPlain().

Issue #2217877 by Wim Leers, Dave Reid, damiankloip, xjm, chx | catch: Fixed Text filters should be able to add #attached, #post_render_cache, and cache tags.

Issue #2171071 by jessebeach, dawehner, chakrapani, longwave, Gábor Hojtsy, xjm, Wim Leers: Rename drupal_add_library() to _drupal_add_library() and remove its uses.

Issue #2203407 by nod_, sun: Replace #attached library array values with provider-namespaced strings.

Issue #2195753 by tim.plunkett: Changes to config entities that use plugins are not propagated to the plugins.

Issue #2099741 by Wim Leers, wwalc, mr.baileys, eaton, dstol, nod_, effulgentsia: Protect WYSIWYG Editors from XSS Without Destroying User Data.

Issue #1936392 by Wim Leers: Configure CKEditor's 'Advanced Content Filter' (ACF) to match Drupal's text filters settings.

Issue #1894644 by Wim Leers, quicksketch: Unidirectional editor configuration -> filter settings syncing.