It's not implied that it's something completely new, although a dozen of the sub-projects are new projects rather than forks of existing ones. The overall project is not simply a fork of the Android Open Source Project with hardening. That's a subset of the work, and a big part of it. I also added a paragraph to the placeholder index page clarifying the longer-term plans with virtualization: https://grapheneos.org/#roadmap.

GrapheneOS includes sub-projects including standalone projects like https://github.com/GrapheneOS/Auditor and https://github.com/GrapheneOS/hardened_malloc that are portable to other operating systems. This also applies to a lot of work that's under active development and not yet published as part of the stable releases.

It intentionally doesn't stick to the Compatibility Definition Document / Compatibility Test Suite requirements required to be Android, so it can't be referred to as Android, but rather it's an OS with Android app compatibility. It preserves what's actually needed for compatibility in practice, while not being strictly bound by those requirements. The intentional deviations from these are documented, and there are a bunch of them.

> Lastly, I wonder how this will do over time considering Fuschia.

If it ends up shipping as a replacement for the core OS, with Android running in a virtual machine or on top of a compatibility layer like gVisor, that would just mean that there's a better base to build on than before. All of the work done by the project would still be relevant in a future like that. I'm not so sure that's truly going to happen though.