For more on UTF-8's design, see Russ Cox's one-pager on it:

https://research.swtch.com/utf8

And Rob Pike's description of the history of how it was designed:

https://www.cl.cam.ac.uk/~mgk25/ucs/utf-8-history.txt

Thank you for posting these - the Bell Labs crew is just a different breed.

Of course it's Pike and Thompson and the gang. The amount of contributions these guys made to the world of computing is insane.

I consider "designed on a placemat" to be a selling point for any high-quality standard that will last.