If you want to experiment you could get the ufoProcessor repository from
https://github.com/LettError/ufoProcessor
and then make it available to RF in /LibraryApplication Support/RoboFont/external_packages. This is how you do that:

• park the ufoProcessor repository code somewhere safe, for instance ~/code/ufoProcessor. (in which ~ is your home folder)
• make a new text file named ufoProcessor.pth file in ~/Library/Application Support/RoboFont/external_packages.
• A pth file is a simple text file that contains the full path to the repository. For instance, mine contains
  /Users/erik/code/ufoProcessor/Lib
  But obviously yours would have a different path.

Restart RF after those changes. Then you can check in RF if it sees the right folder:

Yay, it works.

Note: this is only for build 1906031450. Newer builds will have the latest version ufoProcessor. I apologise for the fuss, too many things ended up depending on too many other things. Please let me know if you need more help.