AB try 020

The pipeline

<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" name="pipeline" version="3.0">
   <p:output port="result"/>
   <p:try>
      <p:output port="output"/>
      <p:identity>
         <p:with-input>
            <initial/>
         </p:with-input>
      </p:identity>
      <p:catch>
         <p:output port="output"/>
         <p:identity>
            <p:with-input>
               <catch/>
            </p:with-input>
         </p:identity>
      </p:catch>
      <p:finally>
         <p:identity>
            <p:with-input>
               <finally/>
            </p:with-input>
         </p:identity>
      </p:finally>
   </p:try>
</p:declare-step>