OpenPilot pretends it's the ADAS and some cars you can pass the torque sensor on the custom serial bus used by the cars. There's not much difference in tricking or pretending or overwhelming the serial bus with another data message to make the steering system respond to OpenPilot.

If I recall correctly no car with standard harness openpilot support use an intercept configuration, only community supported cars.

The message it's sending is distinct from the torque sensor reading. There is a dedicated message ID for automated steering inputs, usually used for lane keeping assist and for jiggling the wheel as a departure warning.

I tried programming a module for my car without a lane assist ADAS system. I only stopped because it was my daily driver. I am still saving up for another car so I wont be afraid to break my car.