Displays the table of file name extensions and the associated
 Content-Type and Content-Transfer-Encoding that is employed when
 files of each type are attached to an outgoing message using the
 ADD command.

 Like the CONTENT_TYPE table, the FILE_TYPES are defined by
 built-in entries, followed by system-wide entries, followed by
 local user-defined entries.  File type definitions are found in
 the configuration file MIME$FILETYPES.DAT, which is found in
 the SYS$MANAGER: directory and in the user's SYS$LOGIN: directory.