See the screenshots below for example.
Added already in version 3.2.64.
Comment Added:An Administrator of a site will often collect a particular set of Downloads into a single Category, which may have sub categories.
Then by using the Show Single Category menu item and selecting that Category will enable users to see the intended set of sub categories and their Downloads.
However the header part of the view will usually show the 'Overview' button! Clicking on this will, until now, show all Categories and Downloads as controlled by their Access settings.
The addition to the Single category Menu Item, in setting "Use 'All Categories' as 'Overview' Link" in the list Layouts tab allows a choice of either showing all categores as before or by selecting 'No' to limit the view as originally shown by the Single Category menu item.