gentoo-overlay/app-text/xiphos/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>theology</herd>
  <maintainer>
    <email>theology@gentoo.org</email>
  </maintainer>
  <use>
    <flag name='webkit'>Use <pkg>net-libs/webkit-gtk</pkg> instead of <pkg>gnome-extra/gtkhtml</pkg></flag>
  </use>
</pkgmetadata>