gentoo-overlay/app-misc/tracker/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <maintainer type="project">
    <email>gnome@gentoo.org</email>
    <name>Gentoo GNOME Desktop</name>
  </maintainer>
  <use>
    <flag name="cue">Enable cue sheet parsing</flag>
    <!-- 'firefox-bookmarks' instead of 'firefox' to prevent most users from
	   enabling this by accident; it has some stability problems and
	   performance implications -->
    <flag name="firefox-bookmarks">Install bookmark data miner plugin for
    <pkg>www-client/firefox</pkg> and <pkg>www-client/firefox-bin</pkg></flag>
    <flag name="gsf">Enable <pkg>gnome-extra/libgsf</pkg> based data extractor and
  for ODT.</flag>
    <flag name="iptc">Enable extraction of IPTC data from pictures</flag>
    <flag name="iso">Enable extraction of metadata from ISO disk images</flag>
    <flag name="miner-fs">Enable tracker-miner-fs (required for filesystem indexing)</flag>
    <flag name="nautilus">Enable tracker to integrate with
    <pkg>gnome-base/nautilus</pkg> by providing entries in its context menu
  </flag>
    <flag name="playlist">Add support for playlists</flag>
    <flag name="stemmer">Add word stemming via <pkg>dev-libs/snowball-stemmer</pkg>.</flag>
    <flag name="thunderbird">Install email data miner plugin for
    <pkg>mail-client/thunderbird</pkg> and
	<pkg>mail-client/thunderbird-bin</pkg></flag>
    <flag name="xps">Add support for XPS file format through <pkg>app-text/libgxps</pkg>.</flag>
  </use>
</pkgmetadata>