Including sabre/vobject in ProcessWire. The VObject library written in PHP allows you to easily parse and manipulate iCalendar and vCard objects. The goal of the VObject library is to create a very complete library, with an easy to use API.
School holidays für the federate state Northrhine-Westfalia. iCalendar abonnement available here: https://qualyweb.com/en/calendar/holidays/nrw.ics
Data source: https://www.kmk.org