This is exactly what I was looking for!

They feature an "Ask AI" widget in the bottom-right of their own docs site (https://docs.kapa.ai/) and some of their customers are doing the same: https://www.prisma.io/docs | https://docs.mapbox.com/ | https://circleci.com/docs/ | https://fusionauth.io/docs/

kapa has a nice dashboard where you can select what you want to include in the RAG backend (docs, code, forums, discord...). They also do some things with showing you what users are asking, the responses and ratings, and being able to make corrective actions (?)

I saw a dev tools company poking around on a video call at one point, don't have access myself

That’s cool. I can see them expanding to become the Intercom for Developers.