School Holidays
If you ever need an iCal format of the Berlin school holidays calendar (or any other states in Germany), you can go visit this website to get a URL
https://www.schulferien.org/deutschland/ical/
And then in Google Calendar you can add it on this page
https://calendar.google.com/calendar/u/0/r/settings/addbyurl
The only downside is that you have to do it once a year.