I ran emerge -vup world and noticed the following line. [ebuild U ] net-fs/samba-3.0.5 [3.0.4-r1] ... -oav ... Not knowing what the oav USE flag was I checked http://www.gentoo.org/dyn/use-index.xml and didn't find it. I also checked /usr/portage/profiles/use.desc using grep and didn't find it there either. Reproducible: Always Steps to Reproduce: 1.grep oav /usr/portage/profiles/use.desc From looking at the ebuild, oav seems to be related to virus scanning software.
that's a local use flag. it is documented in /usr/portage/profiles/use.local.desc. Only global use flags are documented on the web site.