The IDL specifies a string return value, and the prose description indicates that this value is a chunk of HTML representing a table of the calendar listings.
The IDL return value is represented by a value in the body of the SOAP response. Since the value in this case is HTML, and SOAP is XML, we have to be careful of confusing the HTML tags with XML structure. In general, this is something to be mindful of when sending strings containing HTML or XML in SOAP messages.