The document is confusing in several places as to what is being defined. The schemas define all of xcal, the document talks mostly of WS-Calendar (which is now structured as an extension to xcal).
Line 368 demonstrates this with the "Use in WS-Calendar" contasting XCAL and WS-Calendar. Likewise Line 657 "Text" "Discussion" says "The use of text in WS-Calendar is not defined"
So which is being specified? This relates to another issue, WSCALENDAR-305, which recommends a simple model (Platform Independent Model) that is compatible with the broader model.
Table headings don't help. Table 3-1 headings are "element, use, use in WS-Calendar"
But is the broader model xcal or ws-calendar? Or is ws-calendar a profile on xcal?
This is a general description and discussion issue throughout the document.