It means that for every 1% you move the throttle pedal, the ECU will move the throttle plate open 1%. So at half way throttle pedal travel, the throttle will be open 50%. Foot flat to the floor, the throttle will be open 100%.
As standard the car is fly-by-wire which means the movement from the throttle pedal is interpreted by the ECU and the throttle plate moved as much or as little as the ECU deems required. As such it doesnt move it 1:1 based on the pedals, it bases it on other paramters such as engine load, engine revs and the gear you are in too I think.
So UpRev can play with this map or transalation from pedal position to throttle opening, with the *holy grail* being 1:1. I'm not sure how much it can tweak it before he breaks the cruise control, but there is some movement. Mark from Abbey will be able to explain more
Thats my understanding, altough things may have changed by now.