A long time ago, you built a web service. It was long enough ago that you chose XML as your serialization format. It worked fine, but before long, customers started saying that they’d really like to use JSON, so now you need to expose a slightly different, JSON-powered version of your API. To make it easy, you release a JSON client developers can drop into their front-ends.

Conor is one of those developers, and while examining the requests the client sent, he discovered a unique way of making your XML web-service JSON-friendly.

{"fetch":"…"}

Simplicity itself!

https://thedailywtf.com/articles/bassackwards-compatibility