In the repo with the code. Seeing commits where both the code and doc change together is a sight to behold.

Okay, but again, which documentation is that? Technical or business?

Because I do not see business documentation evolving with code. And depending on what the code does, business documentation could be much more important than technical documentation.

That's how our conflusence is used.

Some departments do stupid things like duplicating information. We use confluence to describe the requirements, the concepts, then point to the right locations.

Take IPs, some departments have pages and pages with the same IP, subnet, etc in

You can do that in confluence.