Windows OS does not provide a GUI to dissociate file type extensions. If you need to remove file association, you can use Unassociate File Types utility.

OpenWith Enhanced replaces this basic tool with one that tells you which programs are the best options, lets you remove associations, and even change icons for specific file types.

MSFT says this is to prevent apps hijacking file type associations. This would be good, except that Windows itself doesn't allow users to change it.