Document -j flag / Provide documentation on how to create plugins & limitations of plugins

[voltagex]

I am trying to work out whether -j mycustomplugin is enough to say, get SSH keys out of 1Password

I have read the code but I don't fully understand it yet.

I see other people have written plugins, but it seems to change the "key type" where I want to create a plugin that "just" changes where the encryption key comes from