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>
<herd>freedesktop</herd>
<use>
  <flag name="applet">Build tracker monitor applet</flag>
  <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="flickr">Build flickr data miner</flag>
  <flag name="gsf">Enable <pkg>gnome-extra/libgsf</pkg> based data extractor and
  for ODT.</flag>
  <flag name="introspection">Use <pkg>dev-libs/gobject-introspection</pkg>
    for introspection</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="laptop">Make tracker power management aware</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="strigi">Add support for <pkg>app-misc/strigi</pkg> search
  engine.</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="upnp">Add support for video extraction via <pkg>media-libs/gupnp-dlna</pkg>.</flag>
</use>
</pkgmetadata>