I have an extensive list during my mime.types apply for Apache, however you will find lots of lines proclaiming a mime-type with no connected extension. Are proclaiming these mime-types with no extension just a total waste of space?

I observe that the svn mime.types (link below) list comments the lines with no extension, however the standard mime-types file that Apache installed left individuals lines uncommented, so I am a bit confused. Can anybody shed some light about this?

http://svn.apache.org/viewvc/httpd/httpd/branches/2.2.x/docs/conf/mime.types?view=annotate