Per the GitHub API docs, I am requesting the repo scope which gives access to private repositories.
The user is presented with the following dialog, which also ment
(I'm a newbie with Git and was using the command line following https://developer.github.com/guides/getting-started/ but I had trouble with quoting etc. So I switched to using a browser and made some progress)
In the browser my url is
https://api.github.com/user/repos?access_token=deadbeefdeadbeefdeadbeefdeadbeefdeadbeef
where I have swapped in fake token for my real one (tokens should be treated like passwords are not shared).
This gave me complete list of my private repositories in JSON.