<?xml version="1.0" encoding="UTF-8"?>
<sch:schema xmlns:sch="http://www.ascc.net/xml/schematron">
<sch:ns uri="http://www.inkscape.org/namespace/inkscape/extension" prefix="inx"/>
  <sch:pattern name="duplicateOptionValues">
    <sch:rule context="//inx:param/inx:option">
      <sch:report test="preceding-sibling::inx:option/@value = @value">Warning: @value values should be unique for a given option.</sch:report>
    </sch:rule>
  </sch:pattern>
</sch:schema>