Thanks, just having that verified helps. It seemed like that had to be true (that they are wired differently than other templateVMs due to tighter coupling requirements than simple overlays can provide). I suppose that whatever sharing of components that was configured at build time persists across domain updates so that the other templates are notified of installed package changes among each other. I believe dom0 also receives the same or similar notifications.
Hi thanks for the info. that's exactly what I was looking for.