About nsd config as root-server

Hi,
I tried to verification to use root-server with nsd(4.2.3).

NSD compiled with below option:
--enable-root-server
--disable-ipv6
--enable-bind8-stats
--enable-zone-stats
--enable-ratelimit
--enable-ratelimit-default-is-off
--with-libevent=no

And configuration for root zone is below:

zone:
    name: "."
    zonefile: "root.zone"
    include-pattern: "master"
    multi-master-check: yes

And "root.zone" file is below:

$TTL 300
. IN SOA x.rot-servers.net. postmaster.root-servers.net. (
                                2020112502 ; Serial
                                3600 ; Refresh
                                3600 ; Retry
                                86400 ; Expire
                                3600 ; Negative cache TTL
                                )
                                                IN NS x.root-servers.net.
x.root-servers.net. IN A XXX.XXX.XXX.XXX

NSD booted but below log outputted to log file:

Hi Shuji,

In your configuration, you've used the "include-pattern" option. It seem
you have a "zonefile" option in the pattern that's overriding the name
of the master file.

Regards,
Anand

Hi Anand,

It seem you have a "zonefile" option in the pattern that's overriding the name
of the master file.

That's right, comment out "zonefile" option in "include-pattern" option
and resolved this problem.

Regards,
Shuji