Open source is not a marketing adjective here. It is the operating assumption that code, docs, and design thinking should be legible enough to inspect, challenge, and improve, which is less glamorous than saying “radically transparent” but much more useful.
That does not mean every repository is public, every draft is polished, or every decision happens by committee. It means the default operating model should be understandable from the outside and editable from the inside.
The point is clarity and participation. If someone wants to understand how the work is done or contribute to it, the path should not disappear behind proprietary tooling, locked workflows, or a CMS that acts like it deserves creative control.