How to contact the Obsidian Hub Group? That repo seems to be concerned more with meta-info around Obsidian itself.
I am also interested in setting up a shared Repository, but primarily with reference data, similar to Wikipedia and Wikidata. That is less controversive and product-neutral.
User Folders are a good idea, but it may branch out into a set of isolated, not integrated Branches.
Have a look at this repo of chemical Elements: SpocWeb/Obsidian.Elements (github.com)
I have integrated it as a sub-module into a larger Repo with geographical and astronomical data (not public yet, more is to come)