Where can I find all options for the electrum config file?

I need to add oneserver and my server’s IP to my electrum config on Mac. Also, I want to know which other options for the config there are.

I know that I can start with electrum --oneserver --server raspibolt.local:50002:s on Linux. How can I make this on a Mac – and with the config?

It seems to be that

"server": "bla.onion",
"port": "50002",

Are valid options, but what is with the :s?

EDIT: So,

"server": "bla.onion:50002:s",

worked! It did not work the first time, probably because I had set "auto_connect": "false".

I will still leave the question here.