Issue #2309671 by herom: Fixed admin configuration page RTL CSS.
Issue #2315459 by herom, seiplax: Fixed RTL for config translation form.
Issue #2246679 by YesCT, alimac, Michelle, martin107, eugenesia: Make Language module's LanguageInterface (to be ConfigurableLanguageInterface) extend Core's LanguageInterface.
Issue #2330043 by andypost: Theme handler is not needed for theme manager.
Issue #2329653 by znerol: Remove left over abstract class PathListenerBase.
Issue #2202185 by Wim Leers, effulgentsia, msonnabaum, damiankloip, alexpott: Statically cache Role entities to speed up (User|UserSession)::hasPermission().