From Just Solve the File Format Problem
Digital Performer is Digital Audio Workstation (DAW) software. Originally developed for Macintosh, the file format still bears the name of Roy Groth, the main developer.
Digital Performer file format has the name "RoyGroth" starting at byte 2. This is true from version 2 to current version 10. Type/Creator for older Macintosh versions is PERF/MOUP