JSON encoded data generally has the associated mime type "application/json", however this format is "generic" and contains no structural specification beyond the basic types. MongoDB Extended JSON is a flavour that adds semantic meaning to specific underlying structures (specifically, predominantly single-key nested mappings whose key is $-prefixed), which is way more meaning than expected for just "application/json". It is customary to use an annotation on the mime type to denote the structure or format used within, but none is currently documented on the MongoDB Extended JSON page. Please consider what an appropriate value might be ("application/json+mongo"?) and include it in the documentation.

Thank you!