1788 NIB File Format Text (Mark-up) The NIB file format is used by Interface Builder, a software development application for Apple's Mac OS X operating system. The NIB objects are stored as an XML property list, they are unpackaged upon running an application. 1 Digital Preservation Department / The National Archives 06 Feb 2017 Versions prior to DROID 6.3 may not identify this format correctly 06 Feb 2017 fmt/983 PUID nib File extension 1344 NIB File Format BOF: <?xml version=("|')1.0("|'){8-256}<plist version="1.0"> EOF: IBSystem Version 1 Absolute from BOF 0 0 3C3F786D6C2076657273696F6E3D(22|27)312E30(22|27){8-256}3C706C6973742076657273696F6E3D22312E30223E 1 Absolute from EOF 8 256 494253797374656D2056657273696F6E Has priority over 638 Extensible Markup Language Has priority over 1784 XML Property List