An example of the list that is causing this error
Bug example.odt (application/vnd.oasis.opendocument.text), 10.58 KB, created by Ricardo on 2011-12-15 10:22:53 UTC
(hide)
 
Creator: Ricardo
Created: 2011-12-15 10:22:53 UTC
Size: 10.58 KB

Attachment is not viewable in your browser because its MIME type (application/vnd.oasis.opendocument.text) is not one that your browser is able to display.

Download the attachment.

Actions: View
Attachments on bug 43863: 54472