I went back and did more digging. Then I came back and carefully read your answer. I actually understood it the second time. 
There seems to be a tendency to mix things around a bit. When I made my deck, I used Morgan’s sheet (where Idad is linked with Yew). That matches a couple of other links. CoPilot says that Juniper is a more modern reference. It then gives your lead article to this discussion as a reference (twice). Kinda cool. If you want to see it, I think all you need to do is ask CoPilot to explain Idad.
In any case, thanks for this discussion. Just writing about it helps with the learning.