> the only fundamental difference at that level is that XML has a built-in mechanism for metadata referring to a file's own schema, while in JSON (and I believe the others, even though I've used them less) the schema is not linked from within the file itself
As long as you're using plain DTDs for your schema, yes. Like early XML-based config languages such as idk JSPs/web-app and Jakarta (née J2EE) deployment descriptors used and still use. But later XML configs use XML Schema and namespaces, which are similarly detached from an instance document as eg JSON Schema and the others you mention [1].
As long as you're using plain DTDs for your schema, yes. Like early XML-based config languages such as idk JSPs/web-app and Jakarta (née J2EE) deployment descriptors used and still use. But later XML configs use XML Schema and namespaces, which are similarly detached from an instance document as eg JSON Schema and the others you mention [1].
[1]: http://cmsmcq.com/2005/xml2005-166.html "How schema-validity is different from being married"