回答:
DragDropHandlersを探しています:
HKCR\*\shellex\DragDropHandlers\
HKCR\Directory\shellex\DragDropHandlers\
HKCR\Drive\shellex\DragDropHandlers\
HKCR\Folder\ShellEx\DragDropHandlers\
HKLM\SOFTWARE\Classes\*\shellex\DragDropHandlers\
HKLM\SOFTWARE\Classes\Directory\shellex\DragDropHandlers\
HKLM\SOFTWARE\Classes\Drive\shellex\DragDropHandlers\
HKLM\SOFTWARE\Classes\Folder\ShellEx\DragDropHandlers\