gentoo-overlay/sys-libs/freeipmi/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <maintainer type="project">
    <email>sysadmin@gentoo.org</email>
    <name>Gentoo Sysadmin Project</name>
  </maintainer>

  <use>
    <flag name="nagios">
      Install a nagios plugin to check sensors' status.
    </flag>
  </use>
</pkgmetadata>