Issue #3055198 by catch, longwave, mikelutz, alexpott: [Symfony 5] Symfony/Component/EventDispatcher/Event is deprecated in Symfony 4.3 use Symfony/Contracts/EventDispatcher/Event instead

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

Issue #2392351 by alexpott, swentel: When an entity bundle config gets deleted, entities of that bundle break

Issue #1890784 by alexpott, YesCT, heyrocker, tim.plunkett, EllaTheHarpy, beejeebus: Refactor configuration import and sync functions.