APR of locking is 954%? Is that for real?

So I'm looking at the locking protocol for governance and it's saying the 3yr 11mo lock rate is 954% APR approximately?

Presumably at a level like that you 10x your money each year and over a period that long you'll end up with about 10,000x whatever you lock? Is that correct?

I'm really surprised it's so high, are the rewards from a fixed pool which will decline in size as more people take their rewards and lock or as rewards start to be paid out?

Does anyone know the formula for the calculation of it?