By default, you are probably uniquely identifiable: the SSH client sends your public keys, and sites like GitHub and GitLab publish the public keys for each account too. Someone made a demonstration SSH server a few years back that would greet you by GitHub username based on this, but I can’t immediately find it.

If you don’t specify a username, your local account name will be used and thereby disclosed.

Much more seriously, if you have the ForwardAgent option enabled, the remote server can impersonate you, using your SSH agent to log into any remote server. Don’t enable ForwardAgent globally, despite its convenience, unless you have an agent that requires manual action for every action; and be exceedingly leery of using it even on trusted servers, lest the compromise of one machine allow the compromise of everything. Consider ProxyJump instead.

I think this is sufficient regardless of configuration (but don’t trust me to be correct, I haven’t verified the actual traffic or anything):

  ssh -a -o PubkeyAuthentication=no nobody@git.charm.sh

It’ll prompt you for a password, just press Enter, it’ll accept it.

Now of course using this will make you comparatively fingerprintable (though not identifiable) unless enough other people do it too. But then, they have your IP address, so—

If you want to skip the host key stuff, you can add `-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no`, though it’ll emit a warning about adding the host key to the known hosts file every time.