From What's New in CC 3.44:
Enhanced: Export FBX > Blender Preset will now export JSON files.

Great! I was excited as I read it. Did a quick test.
Oh well, it is not getting parsed on import back from Blender (or just partially parsed).
Seems all maps are getting imported back (even displacement).. but not the opacity. None of them are present on any material.
I am not even going to mention skingen...
So my original request for 2 ways pipeline is still valid: https://www.reallusion.com/FeedBackTracker/Issue/Importing-characters-back-from-Blender-to-CC-Please-develop-GoB-or-similar