Do you mean to say Zed wasn't vibe coded? There's actually another comment on this post describing how someone is using Opus 4.5 to work on Zed. Given how forward the AI features are in Zed I'd be surprised if the team wasn't also embracing it internally.

It's a fair question how much AI is accelerating the development of Zed, but I can say that I've been impressed with the speed they are shipping at.