From MusiCAD

In MusiCAD many types of files are used.

Each file type has its own extension (everything after the period in a file name).

.abc ABC files
.arr Arrangement Files
.bmp Bitmap files
.gif GIF files
.ini Settings
.jpg JPG files
.mid MIDI files
.min Instrument-definition-files
.mc MusiCAD music
.~mc0 .mc0 MusiCAD backup
.~mc1 .mc1 2nd MusiCAD backup
.~mc2 .mc2 3rd MusiCAD backup (etc.)
.mcd chord diagrams
.mck keyboard definition
.mfr Fragment files
.mpl Play list
.msd Hotkey definitions
.msj layout templates
.mtl Toolbox
.mxl Compressed Musicxml files
.musicmxl Musicxml files
.tmc score templates
.txt Text files
.pdf PDF files
.png PNG files
.ps PostScript files
.license Musicad license file