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?
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.
Nostalgia! I don't remember them coming out, but I was involved in setting up Calibrite. I was more involved in the monitor calibrators (my team developed the new software) and the infrastructure.
Pleasantly surprised to see dpreview still running, I thought they had shut down. It was a fantastic site back in the day. Not sure how it fares these days.