How does Mulberry know which application to launch to view an attachment?
Mulberry uses the mailcap MIME type to application mapping scheme to determine what application to use for viewing an attachment. The standard mailcap file format is described in RFC1524. Mulberry looks for mailcap files in the following locations (if they exist):
/usr/etc/mailcap
/usr/local/etc/mailcap
/etc/mailcap
~/.mailcap
If more than one file exists, Mulberry reads in the entries in each file determined by the order above, and duplicate entries are replaced. Thus an entry in /etc/mailcap will be overridden by an equivalent entry in ~/.mailcap allowing users to override site defaults with their own settings, if required.