According to documentation, when broadcastPastEvents is true, maxNumberOfDays past events are showed, however, what actually happens with the default calendar
https://ics.calendarlabs.com/76/mm3137/US_Holidays.ics
is that only events to come are showed, unless once set the pastDaysCount option to some value.
I would like that documentation would be clear about which variable should be set to show events N days in the past AND M days in the future.