I see this as not just internal API/architecture/code documentation, but product documentation too. We maintain internal docs about how our product is used for our support, implementation, and sales teams to reference.

Right now it's hosted externally (in our "blessed" knowledge base) but if it could be pulled into the repo, and we set an AI reviewer on every pull request to sanity check that if the changes we're doing have a material impact on the feature as described in those docs that it should be flagged (or changes proposed) that'd be a nice win for keeping them up-to-date, and it's easy enough to publish markdown as html or even script an update to the canonical site when we merge to main.