See on https://ycr.org/
Same with HARC - any post mortem?
I'm really glad that YC is ambitious and tried to do these things. Of course, failure is a natural part of ambitious bets. I'd also love to hear what they learned and why they didn't end up being overwhelming successes.
My guess: They figured that out and quietly axed it. There's probably not going to be a post mortem. No real point in spending more time, energy or other resources on it.
[1] https://cities.ycr.org/blog/2016/07/27/new-cities
[2] https://www.fastcodesign.com/90133913/this-california-ghost-...
[3] https://news.ycombinator.com/item?id=16537630