What does the rear wing actually do?

[Bagman]

At the start of the weekends racing I broke off the rear wing and snapped the mount. Raced the rest of the day with no wing and I'm not actually sure if I noticed a difference. I did at the start over the jumps but I think it was psychological more than anything. I always thought it helped stability over jumps but I'm not 100% sure now and would be grateful for a more expert view.