Debain DNS Documentation Discrepancy, .ref or .db?

[Stephen Pflanze <artist@speakeasy.net>]

I had a point of confusion in the document:
http://www.debian.org/doc/manuals/network-administrator/ch-bind.html
under "8.4.2.1 zone files." It appears there is discrepancy in a file 
name extension here. This section refers to the path and filename 
"/var/named/192.168.100.db" and gives an example of it. An entry in the 
file "/etc/named.conf" is supposed to point to the file 
/var/named/192.168.100.db" so bind can find it. But this filename is not 
present in the given "/etc/named.conf" example. Instead there is the 
filename "192.168.100.rev". This led to confusion for me until I 
realized there is a mistake here.