I worked on a new Plone add-on to manage and to provide software product add-ons during the last weeks. This new add-on, named collective.addons, runs on Plone 5.2 and Python 3. It has currently a localization in German language too, but it would be easy to add further localizations to the add-on later. It needs only the creation of a subdirectory inside the locales subdirectory and a new po-file for the further language.
The source code of the new Plone add-on is available at the Plone community repository at Github: https://github.com/collective/collective.addons