One subtle benefit of the opt out is that it forces commercial ML companies to reveal what they trained on. So Copilot would need to reveal a list of repositori

One subtle benefit of the opt out is that it forces commercial ML companies to reveal what they trained on. So Copilot would need to reveal a list of repositories, in order to give the repo authors a chance to opt out. This is a fairly big deal since right now there’s no incentive for AI companies to disclose their training data, and it seems unlikely that legislation to that effect will be enacted anytime soon. Whereas this opt out mechanism is already getting widespread adoption in the EU.