Starting from Julia 1.5 you can do this with a subdirectory, e.g. if MyPackageLib is the git root, using the syntax
(MyProjEnv) pkg> add /path/to/MyPackageLib:MyAwesomePkg
(That said, Pkg.add of a local path is relatively rarely what you want, most of the time you rather want to Pkg.develop.)
Good point. I tend to deliberately omit talking about multi-package repositories to avoid throwing out too much information — but also because I don’t feel that comfortable with them yet, for some reason. I’m also not a big fan of pushing this feature yet, in case people are working in pre-v1.5 environments (but that’s probably not a good reason).
I really should start playing with this feature more. It does address a very real issue in a rather elegant (straightforward way).
Though I must say I would probably find them much less confusing if all packages in these multi-package Git repository bundles were registered simultaneously under the same revision number. I realize that means more Pkg complexity, and less flexibility in our solutions, but I think it better fits the way Git repositories work.