Issue #2576533 by alexpott, stefan.r, Wim Leers, dawehner, xjm, effulgentsia, catch: Rename SafeStringInterface to MarkupInterface and move related classes

Issue #2557519 by alexpott, joelpittet: Remove many usages SafeMarkup::checkPlain() and replace with Html::escape()

Issue #2549791 by alexpott, Wim Leers: Remove SafeMarkup::xssFilter() and provide ability to define #markup escaping strategy and what tags to filter

Issue #2547741 by stefan.r, harjotsingh, sdstyles, Wim Leers: Introduce FilteredString and get rid of all SafeMarkup::set() calls in the Filter module

Issue #2506195 by alexpott, joelpittet, xjm, David_Rothstein, Fabianx, pwolanin: Remove SafeMarkup::set() from Xss::filter()

Issue #2457781 by prateekMehta, stefan.r, AjitS, hussainweb: Use Utility\Html class instead of Utility\String for decodeEntities() function

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

Issue #2346783 by Rok Žlender: Fixed Code block in FilterAlign and FilterCaption not closed properly.

Issue #2239413 by Wim Leers, blueminds: Split FilterCaption into FilterAlign (for data-align) and FilterCaption (for data-caption).

Issue #1825952 by Fabianx, joelpittet, bdragon, heddn, chx, xjm, pwolanin, mikey_p, ti2m, bfr, dags, cilefen, scor, mgifford: Turn on twig autoescape by default

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

Issue #2170085 by Wim Leers, jessebeach: Caption filter may not wrap images that are only aligned, not captioned.

Issue #2081155 by smiro: Remove Unused local variable  from /core/modules/filter/lib/Drupal/filter/Plugin/Filter/FilterCaption.php.

Issue #2009018 follow-up by StephaneQ: One more replace theme() with drupal_render() in filter module.