Yeah, they gave a talk about it at NixCon last year:

https://talks.nixcon.org/nixcon-2025/talk/UPHTPD/

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

I don't remember all of the details, so if you're curious you should watch the talk. :)

But IIRC the main points that differentiated this new effort from the old one were that (1) there was buy-in from the very top of the company, (2) they took a more incremental approach where the old one was more all-or-nothing, and (3) they tackled the edge cases and hardest repos first.

The talk includes some info about the failings of their first effort as well. It's worth a watch.