Genealogy of the open-source office suites

I found this useful-looking version diagram of where the various versions came from: https://en.wikipedia.org/wiki/Collabora_Online#/media/Fil... . It appears that
* COOL incorporates recent changes to LibreOffice Desktop
* Patches also flow the opposite way from COOL to LOD.
Sounds like it is, or ought to be, a friendly arrangement of mutual benefit to both projects.

Conspicuous by its absence is any mention of LibreOffice Online, presumably because LOOL was mothballed. Still, would be interesting to see what version(s) it was branched from. And given that the Document Foundation would also presumably be cross-fertilizing patches between its own desktop and on-line version, is it permitted to wonder if this will result in needless duplication of effort?