This is mxPlay 2.1.2, an audio media player for Atari TT030/Falcon030/Falcon060 range of computers.
Read about spreading conditions in doc/COPYING.
Read about plugins included in doc/plugins.txt.
Read about application's functions in doc/using.txt.
As there was exactly zero interest from other programmers about coding plugins, I'm not going to bother with documentation this time, in case you'd like to code / fix a plugin, drop me a line, I'll give you some hints.
Miro Kropacek aka MiKRO / Mystic Bytes Bratislava / Slovakia 10.3.2013