{msg-fields} {{recipient1-fields} {recipient2-fields}}
Where there can be an arbitrary number of recipient fields. Each item
is actually a list of lists. Each sublist contains a key and a value.
| cmd | The command to use to show this body (possibly with '%s') |
| term | A '1' if this program needs a terminal |
| copious | A '1' if this program gives lots of output |
| desc | A description of this type |
| bitmap | The name of an xbm-file which contains an icon for this type |