Using xpra's gui there's a ssh->ssh option, but it doesn't clearly indicate how to provide ssh key for the second step.
My bastion host associates a key with my user that is used to log in to an active job where my xpra command is running. Currently I can't start the client on my local machine because I fail the authentication for the second step of the ssh.
I'd love to know how to provide this key either using the gui shown below, or via the command line which I believe was described in this post https://xpra.org/trac/ticket/2041?cversion=0&cnum_hist=16 and is perhaps in use here with the nested invocation https://www.xpra.org/trac/ticket/597
