Hi, welcome to LQ!
So what exactly is your question?
You can't find information about DLZ on the DLZ site that
you provided a link to? Did you happen to see this?
On a different note: that patch is 5 years old and hasn't
been updated since; there's a good chance that you won't
be able to use it with current versions of BIND, and given
its poor security history you don't really want to use a
five year old version of it in the wild, anyway.