I didn't learn much from reading this article. Questions linger in my mind, for example: What are the CIE XYZ coordinates of each colored square? What is the spectral distribution of each square? How were the colors chosen?

The Wikipedia article is far more informative, though I'm uncertain if read the full dpreview article due to ad-induced nausea.

https://en.wikipedia.org/wiki/ColorChecker

You sound like you actually want to just generate them yourself using ArgyllCMS `targen` and `printtarg`.

I don't know about him but yes yes I do and you should want to, too! :^)

These aren't appropriate questions for the birthday party

These are great, even for manually-adjusted color workflows.

Fun fact, though: You have to replace them every couple of years (or sooner) because no pigment/dye is stable, especially if exposed to bright light.

Having a test shot with one of these in it saves you untold amounts of pain later.

Many of them, especially the smaller hard-case versions, have a space to write date of first-use.