I used surge once recently, and it just works. What I didn't figure out when the same site is deployed to the same domain name, and when it gets a new one. I'm

I used surge once recently, and it just works. What I didn't figure out when the same site is deployed to the same domain name, and when it gets a new one. I'm sure it's documented, it's just not obvious (and for a throw away web page it didn't matter).