Issue #3312198 by catch, alexpott, longwave, Nixou, Spokje, darvanen: Regression concerning the cache of private files

Issue #3292908 by alexpott, dww, longwave, catch, Berdir, Charlie ChX Negyesi, mradcliffe, kndr: Fast 404s are slower than regular 404s

Issue #3113876 by Hardik_Patel_12, himmatbhatia, jungle, klausi, longwave: The "Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent::getException()" method is deprecated since Symfony 4.4, use "getThrowable()" instead

Issue #2901730 by mfernea, ankitjain28may, idebr: Fix 'Squiz.WhiteSpace.FunctionSpacing' coding standard

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

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

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

Issue #2450383 by joshi.rohit100, martin107: Two incorrectly titled Subscriber constructor functions