Most use the auto clutch and auto blip. Auto-blip has to be set somewhere in the player.json file i think. It activates when you use auto-clutch.
Yes, it is stated on the rF2 homepage as well. In the Corvette you have to do the blipping yourself even is auto-clutch and everything is on. I really like it and feels kind of "old school", if you don't know it you will have troubles downshifting on the brakes@Gijs van Elderen i think it doesn't work with semiautomatic transmissions.
I have those options on and had to do manual blip.