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I think that pretty much all religious holidays have now been excluded and there are now apps available to add them if you want. This keeps holidays showing up for people that are not of that faith.
If you do a search of the forum, you will see there have been several threads about this. Many contain links for an additional calendar that contains religious calendars for whatever faith you may be a follower of. You can subscribe to that calendar and you will find the religious holidays for your faith. This is one. https://www.calendarlabs.com/
Why is Good Friday and Easter not shown on the calendar?
