> Watch out for that second link. Not everything there is accurate.

Can you elaborate please? I particularly like their well formedness concept.

Part of the problem is they wrote that site and its content for a specific version of JSON Schema. The `items` keyword no longer takes an array form value in the latest version of the specification, while their documentation shows that it does.

I seem to recall other issues, but can't find them now. We may have raised issues which were resolved, but I don't recall the specifics.