Talking with JV, running the eZ Web toolbar (using a fallback to legacy) on a New Stack twig powered site is possible without new development and should not be a problem.
However, very few people know about it and it might need settings and configuration.
This story aims at making this use case simple for developers when installing eZ Publish Platform and using the Demo Bundle. It should include

• Documentation of the setup to implement the use case
• Test of the setup
• Potentially shipping the setup in the demo bundle
• Blog post to spread the knowledge about it

This is much needed to bridge the gap to eZ Studio