Specifying a valid repository name

I appear to have a valid repository that is subject to a pull request. As the maintainers of the main repository process the PR they are updating my repository. I want to pull their revisions to my repository on my computer, however when I try

git pull git@github.com:wclodius2/stdlib/tree/logger-safe-async-io

I get the response

fatal: remote error:
wclodius2/stdlib/tree/logger-safe-async-io is not a valid repository name
Email support@github.com for help

What am I doing wrong?

It looks to me like you’re mixing up repository and branch name in the remote repository URL. I guess the correct repository URL in this case would be git@github.com:wclodius2/stdlib. You can specify the branch to pull as a separate command line argument (similar to the second example in the git pull documentation):

git pull git@github.com:wclodius2/stdlib logger-safe-async-io

Considering you’re cooperating with the maintainers of that repository it’s probably a good idea to add it as a remote instead of typing the URL every time.