Went to put a roast in & had to make a decision as to which button to push - bake or roast. Had to do a Google to find out what the difference is. I think I had previously only used the "bake" mode.
In my GE, convection bake heats with a circular element that is located in the fan housing. Food does not appear to be exposed to any direct radiant heat. With convection roast, the fan works but the heating elements on the top of the oven also come on. This radiant heat does a good job of browning/carmelization but it is pretty robust so you have to be careful.