In htop, I kill Nautilus, and within one second, it's back, with a new PID!
The restarted Nautilus shows in the Processes list, but has no GUI until I manually launch Nautilus… I've heard mention of Nautilus works in lockstep with the desktop… maybe that is the reason(?).
Is there some sort of "watchdog" program keeping an eye on some distro-critical programs? Monitoring Nautilus doesn't seem like a Linux kernel issue, so I just wonder what is happening here?