Version:            (using KDE KDE 3.5.8)
Installed from:    Ubuntu Packages

People I work with have no idea what those crazy undeliverable reports mean, so I get asked to sift through them to work out if it means the email account just doesn't exist any more, if their mailbox is full, if the address flat out didn't work, and so on.

It would be very nifty indeed if KMail could understand and explain a host of common errors, either by formatting and highlighting so the crucial little bit of text is obvious, or better by displaying a human-readable explanation above the email text that refers to the text below.

For example, rather than having this underneath a load of other text:

      madeup@uidaho.edu on 22/10/2007 11:37
            The e-mail system was unable to deliver the message, but did not report a specific reason.  Check the address and try again.  If it still fails, contact your system administrator.
            < thmailsite3.services.byworkwise.com #5.0.0 smtp; 550 5.0.0 <madeup@uidaho.edu>... User unknown>

Kmail would say:

"Your email couldn't be delivered. It looks like that user doesn't exist on the uidaho.edu server."

Or something better :)