Since PROVIDE type virtuals are gone from the Portage tree, the subsection is hopelessly outdated. Also it doesn't mention new-style virtual packages at all. Probably it would be best to remove it entirely. Documentation about new-style virtuals is in the devmanual already (see <http://devmanual.gentoo.org/general-concepts/virtuals/index.html> and bug 353171), and I think that duplicating it in the dev handbook wouldn't make much sense.
Created attachment 272619 [details, diff] Remove virtuals subsection
Created attachment 272621 [details, diff] Remove virtuals subsection Oops, accidentally I had removed also the following subsection. Updated patch is attached.
Fixed. Thanks