<?xml version="1.0" encoding="UTF-8"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0">
  <start>
    <ref name="e2"/>
  </start>
  <define name="e2">
    <element name="e2">
      <element name="e3">
        <text/>
      </element>
    </element>
  </define>
</grammar>