#2 login

it seems that no gin login is required to run the script, it seemed also not to work via ssh: how does it actually work?

It should require login. The gin upload command tries to use the key generated by gin login first (set using the GIT_SSH_COMMAND). If that fails and you have your SSH keys set up with an SSH agent (system-wide) it can also use that.

it seems it went through ssh without asking for the passphrase (?)...

Did you figure out which key it's using and closed the issue?

yes it was ssh (I think)