Quite a bit of effort has been made to make Mutt the premier text-mode
MIME MUA. Every effort has been made to provide the functionality that
the discerning MIME user requires, and the conformance to the standards
wherever possible. When configuring Mutt for MIME, there are two extra
types of configuration files which Mutt uses. One is the
mime.types
file, which contains the mapping of file extensions to
IANA MIME types. The other is the mailcap
file, which specifies
the external commands to use for handling specific MIME types.
mime.types
mailcap