I thought the rules for holidays on a weekend would be similar to what's commonly observed in the private sector - take the weekday closest to the actual date. But when I went to Wikipedia to confirm, I found this:
New Year's Day, Juneteenth, Independence Day, Veterans Day, and Christmas Day are observed on the same calendar date each year, irrespective of the day of the week.
Implying that if the holiday fell on a weekend it was business as usual for the weekdays on either side. But that flies in the face of actual experience, for example 2023-01-01 fell on a Sunday but Monday 2023-01-02 was the observed holiday when everything was closed. So is the information on Wikipedia incorrect or just poorly worded?
I also tried to find an authoritative list of observed holidays on a government site, but failed. All the lists I found were compiled by private web sites. I'd rather know the actual rules anyway.