MIME types are used in many applications (for instance as part of e-mail
and HTTP traffic) to indicate the type of content which is transmitted or expected.
See RFC2045 at https://www.ietf.org/rfc/rfc2045.txt

Sometimes detailed knowledge about a mime-type is needed, however this module
only knows about the file name extensions which relate to some filetype.
It can also be used to produce the right format: types which are not registered
at IANA need to use 'x-' prefixes.

This object administers a huge list of known mime-types, combined from various
sources.
For instance, it contains all IANA types and the knowledge of Apache.
Probably the most complete table on the net!