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

[H.S.]

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.
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