viewport-028 (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" version="3.0">
   <p:output port="result"/>
   <p:viewport match="para">
      <p:with-input>
         <doc>
            <para>A para.</para>
         </doc>
      </p:with-input>
      <p:identity>
         <p:with-input>
            <p:inline content-type="application/json"
                      expand-text="false">{"key" : "value"}</p:inline>
         </p:with-input>
      </p:identity>
   </p:viewport>
</p:declare-step>