ICalendar.Util.Deserialize.parse_rrule

You're seeing just the function parse_rrule, go back to ICalendar.Util.Deserialize module for more information.

This function builds an rrule struct.

RRULE:FREQ=WEEKLY;WKST=SU;UNTIL=20201204T045959Z;INTERVAL=2;BYDAY=TH,WE;BYSETPOS=-1

will get turned into:

%{
  byday: ["TH", "WE"],
  freq: "WEEKLY",
  bysetpos: [-1],
  interval: 2,
  until: ~U[2020-12-04 04:59:59Z]
}