[skissane]

> For this use case, there would also have to be an extension to the SSH protocol to send such out-of-band information. Maybe this already exists and isn't used?

I don’t think one already exists, but it would be straightforward to create one. SSH protocol extensions are named by strings of form NAME@DNSDOMAIN so anyone can create one, registration would not be required.

The hardest part would be getting the patches accepted by the SSH client/server developers. But that’s likely easier than getting the feature past the Linux kernel developers.