Re: Xcode 9. How the hell do you specify a git repo to open?
The placeholder text says “Search Github or enter repository URL”. Since your repo isn’t on Github the first part doesn’t apply, therefore it’s telling you to enter a URL.
It doesn’t say “search any arbitrary Git server” … basically because there is no such functionality. Git can clone repos using multiple protocols, like SSH and HTTPS, and those protocols don’t (AFAIK) include a way to list the repositories or do a search.
Which is not Git’s fault. It deals with a repository at a time; it has no notion of a larger scale server with lots of repos that can be browsed. That would be a cool thing to have … and that’s basically Github. (Or Bitbucket.) But it’s not part of Git.
So yes, in general you need to know the URL of the repo you want to work with. (Unless it’s on Github.)
I feel like I (and others) have already advised you a hundred times to Just. Learn. Git. It would really help your blood pressure. It would be nice if there were a GUI that obviated knowing any of the lower level details, but there isn’t one, and given the sheer amount of stuff Git does there probably never will be.