From their WEB, it says Windows core.
https://shop.highend-audiopc.com/products/audiophileoptimizer
It also says DSP but bit perfect which is contradictory. I wonder what it does that JRiver DSP plugins don;t. I run JRiver, exclusive, asynchronous mode so I only screw up the bits intentionally: drop level by 3 dB and knock down a bass mode, increased buffer size.
Not sure what the optimizer does, but I would first study their free PDF. It could be some of their tweaks can be done by hand. Getting Microsoft's grubby fingers out of your music does have some of the "magical" results they claim, though they do push what sounds like BS, that may be their advertising copy writer trying to hit the "audiofool" market for an actually useful utility. Don't know. I have a couple of pages of OS tweaks I used on my music server as it is dedicated. If I did not stream with it, I would do a lot more. Could be this is a handy tool to do those things without having to look up each service and parameter.