I just got introduced to this "Falsehoods Programmers Believe About Phone Numbers" page.

https://github.com/google/libphonenumber/blob/master/FALSEHOODS.md

.. which reminds me of a previous good one it's probably referencing: "Falsehoods Programmers Believe About Names":

https://www.kalzumeus.com/2010/06/17/falsehoods-programmers-believe-about-names/

...both excellent documents.