This is an MP3 player for ToaruOS using KeyJ's minimp3 library. That library is released under the LGPL 2.1. This application is released under the ISC license.
On ToaruOS, this will only play 48KHz s16le MP3s as the underlying library does no sample rate conversion and our audio interface only supports 48KHz s16le audio. You can convert MP3s to this format with sox.