 extension iccProfile.Header {
     
     public enum ClassSignature: UInt32 {
+        
+        case unknown
         
         case input                     = 0x73636E72  /* 'scnr' */
         case display                   = 0x6D6E7472  /* 'mntr' */

    }
    
    public enum ColorSpaceSignature: UInt32 {
        
        case XYZ                        = 0x58595A20  /* 'XYZ ' */
        case Lab                        = 0x4C616220  /* 'Lab ' */

        
        public var pcs: ColorSpaceSignature {
            get {
                return ColorSpaceSignature(rawValue: UInt32(bigEndian: _pcs)) ?? .unknown
            }
            set {
                _pcs = newValue.rawValue.bigEndian
