[dmlittle]

It depend on the UUID version you're using. Version 4 (Random) will always have that value be 4 as per RFC 9562. So 99999999-9999-9999-9999-999999999999 is a valid UUID but not a valid UUID v4. If you wanted to be pedantic the website should have been named https://everyuuidv4.com/

https://datatracker.ietf.org/doc/html/rfc9562

[saagarjha]

The last line of https://xkcd.com/566/, except it's UUID formats.

[Dylan16807]

Are you suggesting we should never have made the random one, and stuck with mac address plus timestamp forever?