We'll create fresh WordPress site with Manage Upload Types installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Manage Upload Types enables an administrator to see and change the list of file types that are permitted as file uploads to the media library. This is accomplished by adding an ajax-driven table to a panel on the Media Settings page. Each row has a delete link. Confirmation is required for deletions. There is also a small form to allow additional rows to be added. The form is aligned with the table and contains two text entry boxes. The first is for a file extension or list of file extensions separated by pipe symbols (‘|’) and the second is for a MIME type to be associated with files that match one of those extensions.