The Attachment is "MIME content-type" criteria allows you to create rules that take actions on messages based on the MIME content-type of attachments a message contains.
Where the Attachment is "MIME content-type" criteria makes decisions based on the MIME content-type indicated, the Attachment is "true file type" criteria scans the headers of the actual attached files themselves for the identifying signatures.
The Attachment MIME Type screen appears.
The following examples are valid:
3dm or *.3dm
3dmf or *.3dmf