Getting extensions of a given UTType
UTTypeCopyPreferredTagWithClass is used to convert a UTI to another tag, like file extensions:
NSString *extension = (__bridge_transfer NSString *)UTTypeCopyPreferredTagWithClass(myUTI, kUTTagClassFilenameExtension);
Swift 5
import MobileCoreServicesstatic func fileExtension(for dataUTI: String) -> String? { guard let fileExtension = UTTypeCopyPreferredTagWithClass(dataUTI as CFString, kUTTagClassFilenameExtension) else { return nil } return String(fileExtension.takeRetainedValue())}