I saw this thing when it was launched, but IIRC the reward was tiny (like $100?) so it wasn't worth exposing a good prompt for

For comparison, I won a similar prompt injection challenge ran by a crypto company a while back where the total prize pool was over $100k... I didn't win every challenge though, but my team took home around half of that

The problem with good prompt injections is they have a very short half life once they are out in the wild (especially if they work against frontier models)