@class NSArray, NSDictionary, NSMutableOrderedSet, NSObject, NSUserDefaults; @protocol OS_dispatch_queue; @interface _ASAccountAuthenticationModificationExtensionManager : NSObject { NSObject<OS_dispatch_queue> *_dataConstructionQueue; NSObject<OS_dispatch_queue> *_readOnlyQueue; id _extensionMatchingToken; NSDictionary *_domainToExtension; NSArray *_extensions; NSMutableOrderedSet *_observers; BOOL _errorEncounteredDuringLastExtensionDiscovery; NSUserDefaults *_mobileSafariUserDefaults; } + (id)sharedManager; - (id)init; - (void)dealloc; - (void)addChangeObserver:(id)a0; - (void)removeChangeObserver:(id)a0; - (void)_notifyObservers:(id)a0; - (void)_beginExtensionDiscovery; - (void).cxx_destruct; - (void)_endExtensionDiscovery; - (void)extensionForDomain:(id)a0 completionHandler:(id /* block */)a1; - (void)_buildDomainToExtensionDictionaryWithSharedWebCredentialsDatabaseEntries:(id)a0; @end