My musings on Office 365, search, programming and technology. (June 1st, 2019, I started as a full time employee of Microsoft, thus any post before that date are solely written on my own behalf)
For those working with hub sites in SharePoint you have for a long time used the managed property DepartmentId , later accompanied by RelatedHubSites when hub site hierarchies was enabled.
Now the time has come to have these properties, and some more, added to the public documentation.