To specify the free or busy time type.
This property parameter is defined by the following notation:
fbtypeparam = "FBTYPE" "=" ("FREE" / "BUSY" / "BUSY-UNAVAILABLE" / "BUSY-TENTATIVE" / x-name ; Some experimental iCalendar free/busy type. / iana-token) ; Some other IANA-registered iCalendar free/busy type.
This parameter specifies the free or busy time type. The value FREE indicates that the time interval is free for scheduling. The value BUSY indicates that the time interval is busy because one or more events have been scheduled for that interval. The value BUSY-UNAVAILABLE indicates that the time interval is busy and that the interval can not be scheduled. The value BUSY-TENTATIVE indicates that the time interval is busy because one or more events have been tentatively scheduled for that interval. If not specified on a property that allows this parameter, the default is BUSY. Applications MUST treat x-name and iana-token values they don't recognize the same way as they would the BUSY value.
The following is an example of this parameter on a "FREEBUSY" property.