To be fair I don't get what you want to know. Coherent is already completely separate from game and technically it's can use any GPU or software renderer if OS support such switching. Or you mean something else? And for Coherent internals Uber likely don't have any special information because I mostly sure they just get exactly the same blob as we get. Anyway I don't think it's any different from what Google Chrome doing and source code for Chromium is publicly available.
