the last version I tested this add-on with was released in 2020. The recent downvotes indicate that this add-on might be broken ....
This add-on aims to prevents mindless/accidental deletions.
if you press the shortcut (by default "Ctrl+Del") to delete a card (and note) in the reviewer you should see a confirmation dialog. The default is no. You can change the default in the add-on settings in the add-on configuration dialog.
There is a report that this add-on does not work (see negative review below). Unfortunately I can't reproduce the problem so I have no idea how to fix it. A bug fix is welcome.
I suggest that after installing the add-on you create a new note (and card) that you review and then try to delete it. If you don't see a pop-up this add-on will not work for you. In this case uninstall it.