I'd love to support GOG, but they use psuedo-elements to show their currencies which gives 2 big problems for me (and any extension in general).
These pseudo elements parts do not show up in .innerHTML, .innerText, or textContent (the only js/dom integrated ways of knowing what text elements provide their text content as far as I know) of any given element.

2. Ontop of that I have also found no clean solution to do reversible changes to pseudo elements, and I generally do things in this extension on the principle of "0% chance of fucking sites I alter up"

If you have insight I don't, it would be awesome if you'd share it either on https://github.com/Baizey/UniversalAutomaticCurrencyConverter through opening an issue or via email to baizeydevelopment@gmail.com