No, it's still a separate fork for Java 8/10/11 as of right now, although some distributions like Red Hat/Fedora do ship with it enabled as a "Technology Previe

No, it's still a separate fork for Java 8/10/11 as of right now, although some distributions like Red Hat/Fedora do ship with it enabled as a "Technology Preview" on all their enabled JDKs, so you can just get it out of the box. I think Gentoo has it as well. (If it also means anything, I can confirm that enabling Shenandoah is as simple as taking the corresponding OpenJDK code and replacing the `hotspot` subcomponent with the (compatible) Shenandoah fork'd hotspot component, then just building everything normally.)