I did a student project for server room HVAC fans being annoying back in uni, targeted reduction in those annoying or peak frequencies was a totally acceptable outcome as to not disturb operators (was for a simulated patient in the attached hospital). I'm not an acoustic engineer, so obviously take what I'm saying with a grain of salt (did do a lot of safety and risk work though), making things less annoying is perfectly valid if they're not already harmful to your hearing in the first place.

What's cool to me is that it's just printable, so in theory super accessible and anyone could iterate on it if they desired (assuming it gets open sourced)