Google is trying to standardize on a few configuration languages: GCL (because it was too hard to migrate away from it), Starlark (when BCL is not suitable) and Text proto (for things that don't need logic).
It used to be a complete mess, but a plan was written a couple of years ago. So there's hope of improvement.
That's good to hear, but sad that I (as a SWE/SRE) haven't heard of the plan! Maybe I've been living under a rock, but knowing that I should be building new projects with these and not, say, Piccolo, would be nice. Updating codelabs to reflect this where there are multiple options would also be nice, IIRC the CDP codelab still uses Piccolo, but could probably use GCL fairly easily?
I worked there a decade ago and we were trying out the "gcl2" reimplementation that was based on an actual formal specification of the languages. The semantics were subtly different and we couldn't switch our complex config to it quite yet back then. I wonder if the experiment succeeded or you're back on to the implementation-defined language semantics
It used to be a complete mess, but a plan was written a couple of years ago. So there's hope of improvement.