systemd-system-update-generator — Generator for redirecting boot to offline update mode
/usr/lib/systemd/system-generators/systemd-system-update-generator
systemd-system-update-generator is a
generator that automatically redirects the boot process to
system-update.target, if
/system-update or /etc/system-update exists. This is required to
implement the logic explained in the
systemd.offline-updates(7).
systemd-system-update-generator implements
systemd.generator(7).