It really derives from logic:

a) If it wasn't exclusive then we would have seen some other product besides Bing with this technology by now.

b) Satya has specifically stated that in the event of a breach in contract with OpenAI they have the ability to use the IP to continue development. That clearly indicates it is irrevocable.

Non-contradicted statements made multiple times by Microsoft both now and prior to this brouhaha.

> Non-contradicted statements made multiple times by Microsoft both now and prior to this brouhaha.

The statements I've seen don't match what is claimed, which is why I asked for one that did.