Dr. Nikolaus Klepp via tde-users wrote:
Probably there is an easier way and I used that in the first place to create that file ... mit that's lost in the fog of time ...
It is in the Control Center > File associations
application/octet-stream This MIME type is used for binary files, it's usually a fallback for unknown/generic MIMEs with no specific designation.[1]
so it is bad example