This is a question for the car race fans or experts as it seems to have little to do with English itself.
You do understand each of these words taken separately, don't you?
If you're into car racing, you should probably know what they are referring to.
I've traced to the web you suggested and found the answer as following:This suggests it's a separate race: Monaco Grand Prix Formula Three support race - Wikipedia, the free encyclopedia
(Not a fan)