<http://www.gentoo.org/proj/> doesn't appear to be currently doing anything. I can't see any reason not to redirect to <http://www.gentoo.org/proj/en/>. If I am at <http://www.gentoo.org/proj/portage/>, in my Web browser I can hit O^W^J to go to <http://www.gentoo.org/proj/>. Having then to Oen^J is a bit annoying.
http://permalink.gmane.org/gmane.linux.gentoo.devel.announce/1994: Project pages on www.gentoo.org will be removed after the migration. Maintenance for this legacy service as of now is 'best-effort', no new features will be added.