A MIME type / (properly) media type / (aka) content type is a standardized two-part identifier for file formats and format contents transmitted on the Internet.
A media type consists of top-level type name and sub-type name, possibly ordered into trees, and optional parameters.
top-level type name / subtype name [ ; parameters ]
top-level type name / [ tree. ] subtype name [ +suffix ] [ ; parameters ]
The top-level type names are:
application, audio, example, font, image, message, model, multipart, text, video.
The sub-type name consists of a media type name or other identifying content.
application/javascript application/json application/x-www-form-urlencoded application/xml application/zip application/pdf audio/mpeg audio/vorbis multipart/form-data text/css text/html text/plain image/png image/jpeg image/gif