UITraitChangeRegistration Declaration@MainActor protocol UITraitChangeRegistration : NSCopying, NSObjectProtocol Mentioned inAdapting your app when traits changeBuilding a desktop-class iPad app RelationshipsInherits FromNSCopyingNSObjectProtocol See AlsoObserving trait changesregisterForTraitChanges(_:action:)registerForTraitChanges(_:handler:)registerForTraitChanges(_:target:action:)unregisterForTraitChanges(_:)UITraitChangeObservable.TraitChangeHandler