/etc/ntp -- What is this directory used for?

[Modulok]

The ntpd(8) manpage states that its config file is looked for at
/etc/ntp.conf, by default. Drift files are stored in  /etc/ntp.drift,
but this is overridden to be to be /var/db/ntpd.drift, as specified by
the /etc/defaults/rc.conf file. Keys are stored at /etc/ntp.keys by
default.

Question: If that is the case, what is the directory /etc/ntp used
for? It is only readable by root, so it must be some manner of
sensitive information...

Thanks.
-Modulok-