For Opencart v.1.5.x there is Vqmod version, that doesn't change any system files
For Opencart 2.x there is Ocmod version.
This module improves Category list for admin and gives ability to duplicate category like product's Copy button. Module does Deep copying - that means that all category's data will be cloned from database including custom fields if they presents in default tables (some module adds columns, that can not be copied by others modules, because they copying only default columns).
A new (cloned) category will be assigned with products from source category (products doesn't copied, just creates links as in Link tab). If you doesn't need product linking, you may turn it off.
Also, one more useful trick - Category list in admin panel shows as tree for better representation and Disabled categories shows with pale red background (for OC 2.x only)
Localizations: English, Russian
If you need technical support, found an error or have a question about module - please don't write about in comments, write directly to support email.
Operation of this module was tested with Opencart versions 18.104.22.168 and opencart 22.214.171.124, but I believe it will work with earlier versions. If you find any error or bug, please inform us about and we will fix it shortly.
PS: If this extension was useful for you, please vote for it by clicking Star rating above. It makes us a bit more happy :)