Specifies what media types are allowed for calendar object resources in a calendar collection.
This property MAY be defined on any calendar collection. If defined, it MUST be protected and SHOULD NOT be returned by a PROPFIND DAV:allprop request (as defined in Section 12.14.1 of [RFC2518]).
The CALDAV specify the media type supported for the calendar object resources contained in a given calendar collection (e.g., iCalendar version 2.0). Any attempt by the client to store calendar object resources with a media type not listed in this property MUST result in an error, with the CALDAV:supported-calendar-data precondition (Section 188.8.131.52) being violated. In the absence of this property, the server MUST only accept data with the media type "text/calendar" and iCalendar version 2.0, and clients can assume that the server will only accept this data.