You are not modifying anything in the game.
No he wouldn't be altering game files.
It would be like a virtual keyboard or control that just macros the ignore/mute command with the list of people you want to ignore/mute.
I would ask HT before I shared/distributed it, just as a courtesy. I wouldn't bother asking to use it for myself.
Setting it up on Xkeys is fairly easy in software mode (Vs Hardware mode were you have to flash the device) and It's really easy to do on a streamdeck.