I work at MSFT. I can understand the incentives behind this change. Although I am not sure how different GitHub culture is from MSFT.

I am sure they are closely tracking this metric of Copilot authored PRs so that everyone down from Nadella to the dev and PM for this can use it to hype up GH Copilot. It’s also a simple and clean metric that goes well in your Connects (performance discussion), you could say the feature I worked on led to xx million copilot authored PRs and there is now an AI usage mandate and you need to mention how you used AI to do something more efficiently blah blah. It’s good old promotion theatre. I don’t think its unique to MSFT though and is probably common across Big Tech.

There are alternative ways to gather telemetry data about your usage, then literally polluting the commit message / PR description of the author. Why even consider doing that in the first place?