This program is an audio equalizer for Windows. Well, it's a graphic interface for the text-only Equalizer APO which sounds complicated, but you need to install both programs to get a nice, familiar slider EQ:
Ok, so it looks a bit like a 90s Visual Basic version of a familiar slider EQ, but it works. If you spend any time on Windows it's a nice addition because Windows inexplicably doesn't have a native equalizer and neither does Spotify where I spend most of my listening time. Being able to boost the bass and treble and drop the mids is one of those things I could live without, but now that I have the ability everything sounds better.