I worked on a new Plone add-on during the last weeks. I created this add-on within a Python 3 environment. It runs within a Plone 5.2 instance. During the coding of the new add-on I run into an issue in connection with Zope 4 and filed a bug report.
The code of my new Plone add-on need some further testing and further coding. The add-on provides an environment to upload templates and publish them.