Output port 021 (AB)

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error"
                xmlns:p="http://www.w3.org/ns/xproc"
                xmlns:t="http://xproc.org/ns/testsuite/3.0" xmlns:test="http://test" version="3.0">
   <p:output port="result" sequence="true"/>
   <p:declare-step type="test:test">
      <p:output port="result"/>
      <p:identity>
         <p:with-input>
            <doc1/>
            <doc2/>
         </p:with-input>
      </p:identity>
   </p:declare-step>
   <test:test/>
</p:declare-step>