(Ok, before anyone goes running off telling their colleagues about this great new tech: I literally made all of this up on the fly except the batching stuff. That's actually one of two reasons why this whole shadow-DOM-stuff exists. The other is encapsulation. I think this whole thread is a most beautiful demonstration of Poe's law in its original form.)
I think "shadow-DOM-stuff" refers to the concept of virtual DOMs. The shadow DOM isn't really a virtual DOM though, sure. It's just encapsulated parts of the regular old DOM.