Some of our teachers use Smart Notebook files in Moodle with interactive whiteboards. It is helpful to have these in filelib.php and pix/f so that they can be downloaded and displayed with all the other files in the course.
I have the below added to /lib/filelib.php under the function get_mimetypes_array()
I also have the different pix/f/ images but will try to upload them separately.
This will save me (any maybe others) from having to manually add these after each upgrade.