The information on this page is incorrect and out-of-date?
May well be.
fwbuilder has never been part of the official Openwrt/LEDE, so that wiki page looks just like the author's advertisement for the 3rd party firewall scripting tool.
(The author was a security enthusiast who made a brief visit here. One example here: Security guide for the paranoid
Shouldn't it be removed then? I found it confusing as a new user browsing through the documentation. Just a thought.
Three pages on fwBuilder (found through search) now marked as not being part of the OpenWRT package tree and that fwBuilder does not appear to have been updated since 2013.