I was helping my friend set up RaceChrono with the experimental CAN mode on his 2018 Subaru WRX (US market) and we were disappointed to find that the CAN bus isn't connected to pins 6 and 14 of the OBD-II port, as on most other cars.
A quick-ish Google search has revealed that this is by design starting from the 2018 model year.
Just wanted to let people know if they search for it.
If anyone finds the Enhanced OBD-II PID for the brake pedal position / master brake cylinder pressure, or where to splice into the CAN bus, please let us know!
So far the only non-standard thing we were able to find was the
Brake pedal switch (on/off), at OBD-II PID 0x221233, and the equation was "B / 2.55" if I remember correctly.