Definitely one of the cooler projects to watch while I was there. I recall the goal was to open-source it from early on, so I'm glad to see it come to fruition!
I remember some theories around 2021-2022 that Apple had modified the ANC in AirPods Pro/Max via a firmware update. If I recall, the thought was this was in response to some patent infringement.
Anecdotally, I think I noticed a difference, but I also chalked it up to prematurely-degrading hardware...