On Wed, 8 Sep 2021, Tony Finch wrote:
It's even more funny than that :-) They actually
went back to the Julian
calendar in 1712, and they needed to add back the leap day they skipped in
1700; this extra day became February 30th.
https://en.wikipedia.org/wiki/List_of_non-standard_dates#February_30
Oh, my sainted aunt...
-- Dave