I thought the only thing that had been confirmed about Fuchsia is that apps for it will be written in Flutter. Aside from that I've wondered if maybe it was Google's version of Microsoft's Midori project which was a microkernel operating system written in C# from which many lessons learns have been implemented in what we know today as Windows 10.

Or it could be a plan to abandon Android in order to avoid Oracle's Java API lawsuits.

It would have been cheaper to buy Sun instead of hoping that no one would pick it up.

Now they have a scene manager that is UI framework agnostic.

https://fuchsia.googlesource.com/fuchsia/+/HEAD/docs/the-boo...

And ART is being ported to run on Fuchsia.

https://android-review.googlesource.com/q/status:open+Fuchsi...

So it remains to be seen.

By default GUI apps for Fuchsia will be written in Dart with Flutter SDK.

Fuchsia also supports C++ so I imagine you will be able to use Qt et al.