MIME - "Content-Type" Header Field
Two level hierarchical typing scheme adopted of the form: basetype/subtype
Seven base media types are defined this minimal set is enforced, i.e. all extensions must pass the whole ID->RFC->STD process.
Allow for less restrictive subtyping the base types, for example:
- Content-Type: text/plain
- Content-Type: text/richtext
Some standard subtypes are specified and many more are expected. New subtypes must be registered with the IANA (Internet Assigned Numbers Authority).
Private experimental subtypes prefixed with "X-" may be used freely and without registration.
Seven base types are: text, image, audio, video, multipart, message, application.