On 23 Feb 2021, at 22:10, Steven D'Aprano <steve@pearwood.info> wrote:

There are exactly 2**4 = 16 boolean operators of two variables. Python 
only supports two: `and` and `or`. Plus a single unary operator `not` 
(out of four possible unary operators). What makes xnor so special that 
you want it to be an operator?

Python implements more then 2 of them:

True
False
not
and
or

https://en.wikipedia.org/wiki/Boolean_algebras_canonically_defined#Truth_tables

Barry