[Koha] for yaz and zebra, do I need etch-backports repo?

Hi, I am trying to install Koha 3.0.1 on Ubuntu 8.04 (Hardy). While following this wiki: http://wiki.koha.org/doku.php?id=koha_3_install_guide_ubuntu_hardy I see that I need to add Sarge and etch-backports repo. Yaz and zebra appear to be available in Sarge. Why do I need etch-backports for? What does it provide for Koha installation? Thanks. -- Please reply to this list only. I read this list on its corresponding newsgroup on gmane.org. Replies sent to my email address are just filtered to a folder in my mailbox and get periodically deleted without ever having been read.