Question: Foxiest of the Hounds Achievement Check Source Code Location

I'm scouring your code to find out how you can tell if a player is disqualified from the "Foxiest of the Hounds" achievement. I saw it pop up on your youtube channel, but I'm unfamiliar with C/C++ and hooking. Could you point me to the part of the code that determines if the player is still eligible for the achievement?

Second, is it possible to determine this from just checking the save files?

I did some ctrl+fs, but couldn't seem to find how you could tell. Much appreciated if you could provide some pointers.

Thanks again for writing this tool, this is really amazing.