I'd never seen this before! I found it in the Imperial Library while searching for some kind of Morrowind Art book. There are lots of old screenshots and a full scan of the artbook there too! These are staged screenshots, though in-engine, translating concept art of game and interface into engine tests, basically, but it's fascinating to see! There are a couple more in the art book, but the resolution of the scan is too small for further detail.
I put some things I noticed about them in the alt text for each screenshot (in a descriptive way, not in a discussion-y way where possible).
But a big one I love is that 'Spell Points', what came to be called Magicka, used to be green, and Fatigue, ever-poor choice of name for the resource, was blue! Absolutely wild!
Also, the UI in many different configs is likely an artifact of development, but I wonder if it was partly the origin of the very adjustable menu UI we got in Morrowind, which few if any games have matched in simplicity of customization access since.
