/lib/systemd/system/cron-update.service is in systemd-cron 1.3.1+ds1-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | [Unit]
Description=systemd-cron update units
Documentation=man:systemd.cron(7)
[Service]
Type=oneshot
ExecStartPre=/bin/systemctl daemon-reload
ExecStart=/bin/systemctl try-restart cron.target
|