[From proton subreddit]
We are happy to announce that public holidays are now available in Proton Calendar.
You can now incorporate public holidays in your calendar and plan long weekends ahead, avoid scheduling conflicts, and be more efficient with your schedule.
Browse the list of available countries and select yours to get started.
Learn more from our support site : https://proton.me/support/public-holiday-calendars
Nice! Can’t wait for them to make their proton calendar app good