PSO2 Daily Calculator is divided into 5 parts.
Daily Orders - DailyOrder.json
Daily Orders are repeated in a 93 day cycle.
The orders are calculated by calculating the difference between the input date and start date mod 93 (plus 1 since schedule starts on day 1) and searches for all orders that appears on that day.
Exploration Quest + Orders - Exploration.json
Calculates which Exploration Quest is active. Also contains the daily orders associated with the exploration. 16 day cycle.
Feature Quest
Calculates which 2 feature quests appears on that date. 21 day cycle
Level Quest
Calculates the level quests. 5 day cycle.
Extra Order
Calculates any daily orders not part of the 93 day cycle.
Currently it is between Buster, Ultimate and Emergency/Urgent.