I guess this is something thrussh should get, rather than pijul, but I am not sure about the activity of the thrussh repo, and maybe we will have to modify pijul too to leverage this (new) feature. This is why I create an issue in this repository too.
Anyway, the title is pretty self-explanatory. It would be awesome, to say the least, if pijul could use the configuration file of SSH (to know which pair of key to use for a given domain, for instance).
I can't believe I just implemented this, and it worked in just a few hours (mostly refactoring and updating my mental model of the new Tokio).
I'm currently uploading a new companion crate for Thrussh called thrussh-config, containing helpers to parse .ssh/config files, and a type called Stream which can be either a plain TCP socket or a proxy command implementing AsyncRead and AsyncWrite.
Future work includes parsing the easy bits of the file.