This looks really interesting, thanks for linking. Is this a Google project? It wasn't immediately clear.
It was originally developed at Google, but Marcel is no longer there, there is a team and company behind it now.
The language is going to a foundation (still waiting for update from the CUE team), fun fact, it started as a fork of Go (for the lexer, parser, and a bunch of goodies in that source tree)
CUE's history is from borg, borgfig, GCL, but takes the approach Marcel always wanted to if not tied to the existing practices in a large company, namely Typed Feature Structures and logical programming (no overrides, layering, inheritance, general recursion)
We're about to release a TUI for working with CUE, and hoping that it will make learning much easier for people. We do a lot with Cuetorials, but there is only so much you can do on a website (/rant WASM limitations). Using the Go SDK is the way to unlock CUE super powers.
I say the same thing about CUE these days, it can be a real mind bender but gives us a new way to think about taming config and schema complexity. CUE is also much easier to add into existing workflows to turn that logical programming glory into pragmatism.
https://cuelang.org | https://cuetorials.com