A user on Commons reported that he could not upload files with .oga or .ogv because "File extension does not match MIME type."
This is probably because the ogg file needs to be parsed before any mimetype other than application/ogg is detected.....
Version: 1.17.x
Severity: major
URL: http://commons.wikimedia.org/wiki/Commons:Village_pump#.22File_extension_does_not_match_MIME_type..22_on_new_file_being_uploaded