Can blueprints use html files?

In order to make full use of the AUI, I would like to use an html file instead of an xml file to dev a confluence cloud blueprint. I’ve tried updating the atlassian-connect.json & index.js files but the blueprint fails to load, throwng an error that an xml file was expected.

Any ideas where else the code needs to be updated?
All help is appreciated.
Thx

I don’t think HTML is supported, but you could probably use soy-templates in your plugin to build HTML elements.

Take a look here at the documentation:

Thanks for the feedback and links to more details.
Will check it out.