As someone who's done web development for 20+ years, I find the model personalities pretty dang fascinating, especially how they develop (and evolve) design sensibilities.

I'm interested to know how the classic AI "purple preference" emerged (organically?) and if the beige wave came out of specific training efforts to combat it?

To your point on development work (the code itself), I was talking to some friends on the Google Chrome team about any research understanding the model's preferences around framework ergonomics and abilities to properly implement core web standards for given tasks. I think that would be super fascinating.