It’s an open-source, signed driver package called vJoy combined with HIDHide and a configuration tool. Together, they act as a universal translator between almost any joystick (including DIY Arduino ones) and Windows’ native game controller API.
After weeks of testing, I’ve found (and contributed to) a universal joystick driver that actually works across — no registry hacks or legacy compatibility mode headaches required.
Let me know in the comments if you need help mapping specific sticks — I’ve tested over 15 different models.