What's up with the Polymarket?

FBI seizes Polymarket CEO’s phone, electronics after betting platform predicts Trump win: 

https://nypost.com/2024/11/13/business/fbi-seizes-polymarket-ceos-phone-electronics-after-betting-platform-predicts-trump-win-source/

I'd never heard of it until seeing an interview with Mark Cuban:

https://www.youtube.com/watch?v=nYlLjRZM2VE

Then, I wondered about Elon Musk:

https://finance.yahoo.com/news/elon-musk-advocates-crypto-prediction-072206636.html

And, here it is:

https://polymarket.com/