gentoo-overlay/sys-freebsd/freebsd-share/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>bsd</herd>
  <use>
	<flag name='isdn'>Enable ISDN support</flag>
    <flag name='zfs'>Enable ZFS support.</flag>
  </use>
</pkgmetadata>