Note that these tokens are deprecated. Since September 2002, the recommended method of displaying saints and holidays together is to use saints tokens and holidays tokens independently and then combine them using the saints options property.
This token is basically the same as [Fa], but also includes saints, and the possibility of using the corresponding Namedays as Saints Exceptions which are specific dates (January 12 1999, for example) when a religious event overshadows the usual saint for that date. A good example is Easter Sunday which moves around the calendar. In many calendars the saint which usually occurs on a given date is omitted when that date is Easter Sunday. The way Saints are included with holidays is controlled by the ScriptLine property holidays (multiple).
This token is useful if you are combining potentially many holidays on the same date with a saint. However, if you have a list of Saints which are on some dates replaced by only one holiday occurrence, then you should use a saints token which give you the possibility of associating a holidays set for these exception dates.