The Documentation Project Wiki (https://wiki.gentoo.org/wiki/Project:Documentation) has a broken link for the GuideXML Guide and the two other bullet points following that. They point to the old website which returns 404. Reproducible: Always
Reassigning this to docs-team as per bug 569324, comment 5
Per Bug 615366, comment 10 and the warning "The Gentoo Documentation Project is being phased out." on the wiki page, this bug is no longer valid.