gentoo-overlay/gnome-extra/avant-window-navigator-extras/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <use>
    <flag name='gconf'>Enable GConf as configuration backend</flag>
    <flag name='webkit'>Enable support for <pkg>net-libs/webkit-gtk</pkg></flag>
  </use>
  <herd>desktop-misc</herd>
</pkgmetadata>