Today I did a WBR race and finished third in cat d. However I had no real idea of that in the actual race, the only indication was that I was around 50th overall on the last mile, and I let a couple of guys ride away from me, not knowing their category . I would have gone a lot harder if I had known it was for first place in the category. Some people had their cat by their name but not many. I was less than two seconds behind the first place.
On mobile link you can see on the map where the other riders are in your category. As far as I am aware there is not another way to work this out.