I have been looking into how to create a custom theme for experience builder so naturally i started over here:
https://developers.arcgis.com/experience-builder/guide/theme-development/
So I did these steps, and then made sure developer edition had exited, npm rebuild on both server and client before npm start, but my theme is not showing up. Is it possible the needed steps have changed and the documentation is actually out of date? I ask because the experience builder SDK has a demo-theme at:
https://github.com/Esri/arcgis-experience-builder-sdk-resources/tree/master/themes/demo-theme
The first thing i noticed, was not only a thumbnail (just like the custom widgets we build), but also a separate manifest.json file. The documentation seems to be lacking information about the need for these if in fact that's the appropriate mechanisms. (A lot of EXB's documentation seems to assume a tacit understanding that some things are just 'common' from somewhere else in the documentation, but there's often not good linking.
For what its worth I added a manifest.json stopped and rebuilt and started and then it started showing.
More care in ensuring that documentation does not leave out assumptions that are necessary would be of great benefit as many of us are seasoned GIS people, but may not be life long developers (web, react, or type script)
