what is the .50s file extention ??

hello all,

i'm playing around with loopmasters sounds/loops.
each folder has a file with a .50s extention that seems to contain interesting data :

if i change the master tempo of the mpc, the loops (wav files) are following the tempo.

does anybody knows what these file contain and how to make them?

best regards to you all,

xxx

Patched Phrase dude. (maybe spelled wrong)