Custom add-on disappeared after uninstalling

I’ve been making a custom add on to allow energenie devices to be used with HA, to integrate this project: https://github.com/barnybug/engMQTTClient . I’ve tried to create an add-on, when I update the version it won’t appear when I rebuild, and after I chose uninstall (to try and reinstall it) it has completely disappeared from the list of add-ons. I also have a “hello world” add-on in the same directory (/addons) and that is visible but no matter what I do I can’t get the new energenie one to appear under supervisor>add-on store>local add-ons. Is there some way to debug this?

I figured it out eventually that there was a problem with the config.json file, I used an entry for “privileged”=“yes” when it should be a list of flags. I had to do trial and error swapping lines from hello_world until it worked, how is it possible to develop these things with a bit of feedback about what is going on?