[arch-general] Repo Structure - Pool Dir

Hello. Currently I see that there are some packages in /archlinux/extra/os/i686/ and some symlinks to ../../../pool/packages/. I was hoping a dev would be able to answer the following the questions? Eventually, will all packages (from core/extra/community) end up in pool? Repos like multilib, gnome-unstable, kde-unstable will not end up, right? Thanks, ~pyther