We had an IT guy who once bought an XML<->JSON server for $12,000. Very proud of his rack of "data appliances". It made XML like XON out of JSON and JSON that was a soup of elements attributes and ___content___, thus giving you the complexity of XML in JSON. I don't think it got used once by our dev team, and I'm pretty sure it never processed a byte of anything of value.
JSON:
XON: It gives you all the flexibility of JSON with the mature tooling of XML!Edit: jesus christ, it actually exists https://sevenval.gitbook.io/flat/reference/templating/oxn