/lib/systemd/system/mdmonitor.service is in mdadm 3.3.2-5+deb8u2.
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 9 10 11 12 13  | #  This file is part of mdadm.
#
#  mdadm is free software; you can redistribute it and/or modify it
#  under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
[Unit]
Description=MD array monitor
DefaultDependencies=no
[Service]
ExecStart=/sbin/mdadm --monitor --scan
 |