How to install extension from the command line?

I’m diving into Blender’s new extension system that is replacing addons, mostly because I need to use python wheels. Anyhow, I’d like to add a line to my make script that installs the extension after I’ve finished building it. I’m trying to figure out the right syntax to use. According to the docs, I think I need something like

blender --command extension install-file -r REPO --enable extension/kitfox_my_extension-1.0.0-windows_x64.zip

The problem is, I have no idea what the REPO is supposed to be and the documentation doesn’t provide any help. If you leave it out, it refuses to install. This is a just a zip file in a local directory that my script has just built - what should I put for the REPO?

https://docs.blender.org/manual/en/latest/advanced/command_line/extension_arguments.html#command-line-args-extensions

I’m not in front of my computer, so I may be wrong.

But I would run the repo-list sub-command to see which repositories you have available, and pick the one you need.