dbus can also start a program. For example when one notification was generated and no notification daemon is running, then dbus launch one to handle the request.
It transfers contents of a local file ~/.backpack and itself to remote host, sources it and continues with normal ssh session.
works best as alias ssh=backpack won’t create any files on remote hosts (even temporary) tries to fallback to normal ssh when remote shell is not bash self-replication allows you to use backpack again directly from remote host, in this case backpack will keep original local file as you go deaper from host to host.”