File with a .MSCZ extension contains a song created in the MuseScore software, compressed in ZIP format. It may contain song’s metadata (information on its author, title or copyright laws) or a score, information on instruments, duration time.

MuseScore is free software used to compose and store a piece of music. Compressed MSCZ files are standard and the data contained in an uncompressed format are stored in form of text in MSCX files.