When reading MIME messages, Pine uses a mailcap file to determine
    how to display message parts. Mailcap files are described in RFC
    1524, a copy of which can be found as PMDF_ROOT:[DOC.RFC]RFC1524.
    Or see the PMDF User's Guide which gives a brief overview of
    mailcap files.

    The default mailcap filename is MAILCAP. in the PMDF_INIT
    directory, unless the logical name PMDF_MAILCAP_DIR is defined,
    in which case the list of directories defined by PMDF_MAILCAP_DIR
    is searched for the file MAILCAP., in the order listed. The first
    entry found in the list of files will be used. For instance, with
    the following PMDF_MAILCAP_DIR definition, PMDF will use a user's
    own mailcap file, if they have one, and if the user does not have
    a personal mailcap file, PMDF will use a mailcap file in the PMDF
    table directory:

    $ DEFINE/SYSTEM PMDF_MAILCAP_DIR PMDF_INIT:,PMDF_TABLE:

    Note that a trailing colon is necessary if logical names are used
    because the filename MAILCAP. is appended to whatever value you
    have specified.