gentoo-overlay/xfce-extra/xfce4-soundmenu-plugin/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>xfce</herd>
  <use>
    <flag name='glyr'>Enable music metadata searchengine support using <pkg>media-libs/glyr</pkg></flag>
    <flag name='lastfm'>Enable last.fm support using <pkg>media-libs/libclastfm</pkg></flag>
    <flag name='keybinder'>Enable shortcut support using <pkg>dev-libs/keybinder</pkg></flag>
  </use>
</pkgmetadata>