gentoo-overlay/mail-mta/ssmtp/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
  <herd>net-mail</herd>
  <use>
    <flag name='md5sum'>Enables MD5 summing for ssmtp</flag>
    <flag name='maxsysuid'>Allow to define a MinUserId</flag>
    <flag name='mta'>Install symlinks for sendmail-compatible MTA.</flag>
  </use>
</pkgmetadata>