My first attempt has me mapping the funky switch to control pit menu and twisting it adjusts brake bias. Another button on the left side handles rF2 "pit request" function. Upper left button is radio, er, TeamSpeak. DRS (rear flap in rF2) is below pit request. Upper right button is pit limiter.
That leaves headlights, wipers, horn, push-2-pass, and boost adjust yet to be assigned.