Is there a way to give Emacs itself a continuation, i.e. a command to exec when it exits? Copious searching and cursory examination of the source code (grepping for atexit, exit, and looking at emacs.c in some more detail) suggest not.
This would be useful for restarting having updated my configuration (some of which is non-idempotent), as it would save having manually to issue a new "emacs" command having waited for it to shut down; overall, up to several brain-seconds if I don't just sit and watch the process.
It also seems appropriately Lispy to allow a Lisp system's final action to be to call a continuation…