This is fundamentally different from your earlier, stronger claim that - "The very best LLM can answer is the answer you can expect from an online forum like Reddit or a book/paper published more than a year ago."
I use a less popular java framework quite a lot, Micronaut (I want to move away from it, but that's a different discussion).
When trying to solve problems with its behaviour, I can watch as Claude digests the framework source to come up with suggestions, identify bugs that are causing behaviour regressions, and generally unlock stuff that I've previously found very frustrating. Frustrating because the documentation covers a tiny amount of what's in there, and frustrating because there's little online discourse about any of it to refer to.
Is this earth shattering in itself? Probably not. But it's certainly better than you can find from "an online forum like Reddit or a book/paper published more than a year ago".
It’s great at bread and butter stuff, but not at specialised ideation.
If you know differently, please share examples as maybe we can learn something here.