One nice thing about XML is that there's an official way to link to the schema from within the document. If you do that you can easily automatically validate it, and even better you get fantastic IDE support via Red Hat's LSP server. Live validation, hover for keys, etc.
It's a really nice experience and JSON schema can't really match it.
That said, XML just has the wrong data model for 99% of use cases.
That is pretty much what the official "solution" is for comments in
package.json
- add"//": "foo bar baz"
keys to dictionaries and NPM will ignore them.In practice it's terrible. You need real comments.