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
[1]
https://mimetype.io/application/octet-stream