alt Hacker NewsWell, GCL is (afaik) a Google technology, and they do have some kind of internal, fine-tuned models just for their stack.
Who owns the tech doesn't matter, what matters is whether there's a set of diverse examples of its use spread around the internet.
Yeah it's internal, and we have fine tuned models and more lines of it than you can imagine.
That's the reason I think it honestly depends more on the complexity to understand and the necessity of having a mental model of the code.