[Exim] Documentation bug?

Using 4.20.

In chapter 11.8, I read:
The calling host matches the list in host_lookup. The default for this option is
*, so it must be changed if any lookups are to be avoided.

I read this as: when I leave this out of the config, it will be *, and lookups
will be done

But it isn't, so name lookups aren't done. It turns out that setting it to *
also makes $sender_host_name available as ACL variable. Which is good for
customizing error messages.

The ACL stuff is really nice. So flexible and powerful... thanks!


Thomas