More info from a friend about .MUS files:
>It appears that at least 2 and possibly as many as 4 notation programs use
>the .mus/.MUS extension. Besides Finale, there is some program that stores
>the string 'SOLF' in the first 4 characters of the file (at least 13 of
>these), and there are half a dozen other .mus files that are neither of
Viewers or Engraving Programs?
I'm not sure that LilyPond and ABC (to name a couple off the top of my head) fit the description of downloadable tools for viewing and printing scores. Shouldn't there be a separate page for engraving programs/systems? – ChucktalkGiffen♫ 13:52, 8 September 2011 (CDT)