Will IDX ever get open-sourced?

May be partially, but is it on the roadmap?

This is the first Closed IDE I’ve started using

Hi @XADE - currently, there are no plans. IDX itself is based on the CodeOSS project from Microsoft. We have it on our roadmap to make our templates public as well.

To help us plan, is there something you are trying to do (like modify some functionality) that you can only do if IDX is open-source?