/lib/systemd/system/ntp-systemd-netif.service is in ntp 1:4.2.8p10+dfsg-5ubuntu7.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | [Service]
Environment=reason=BOUND
ExecStart=/bin/sh -c '. /etc/dhcp/dhclient-exit-hooks.d/ntp'
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