Maybe it's no longer obvious:

This is an app that plays "MODs", a sampler (?) based chiptune format that originated with the Commodore Amiga.

Inspired by the technical limitations of a 40-year-old design, a demo scene community has created thousands of songs, annual competitions.

The Mod Archive: https://modarchive.org/

MOD format history: https://en.wikipedia.org/wiki/Module_file