Robuta

https://openuserjs.org/garage/Forging_content_type_mime_type
Forging content type / mime type
content typeforgingmimediscussionsopenuserjs
https://contenttype.net/?ref=http.dog
Check the Content-Type header of any URL. Validate if the MIME type matches the file extension.
content typemime typescheckvalidate
https://www.rfc-editor.org/rfc/rfc1563.html
mime content typerfctextenriched