Eventing shows this in the pseudo-schema:
    <wse:Subscribe ...>
      <wse:EndTo>endpoint-reference</wse:EndTo> ?
      <wse:Delivery Mode="xs:anyURI"? >xs:any</wse:Delivery>
      <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires> ?
      <wse:Filter Dialect="xs:anyURI"? > xs:any </wse:Filter> ?
      ...
    </wse:Subscribe>

But the xsd shows:
- the xs:any in Delivery as xs:any*
- attribute extensibility on Delivery
- the xs:any in Filter as xs:any*
- attribute extensibility on Filter

Proposal:
Change the pseudo-schema to match the xsd:
    <wse:Subscribe ...>
      <wse:EndTo>endpoint-reference</wse:EndTo> ?
      <wse:Delivery Mode="xs:anyURI"? ...> xs:any* </wse:Delivery>
      <wse:Expires>(xs:dateTime | xs:duration)</wse:Expires> ?
      <wse:Filter Dialect="xs:anyURI"? ...> xs:any* </wse:Filter> ?
      ...
    </wse:Subscribe>
by making the xs:any on Delivery and Filter xs:any* and adding ... to these
elements.