A remark for the readme:
Yes, I did it manually. ;-)
So far, I haven't bothered to program the tool that derives the visualization. However, I think I've sat down enough to come up with the way I personally would like to have it. This is quoted in my article: https://karl-voit.at/2020/08/14/project-mgt-draft/
I added to my notes the URL https://paste.temporal.pl/trc-workgraph-1-6781.el.html where something relevant should be stored. However, the page is offline and the Waybackmachine didn't index it. :-(
Any progress here would be welcomed by me. Happy to help with testing and feedback, if you want.