gentoo-overlay/sys-power/pm-utils/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <maintainer type="project">
    <email>freedesktop-bugs@gentoo.org</email>
  </maintainer>
  <use>
    <flag name="ntp">Install support for <pkg>net-misc/ntp</pkg></flag>
  </use>
</pkgmetadata>