No, it is actually using the real vim in the background. So while you might not be able to use all vim plugins/scripts, it should give you a much more complete vim experience. See also https://github.com/onivim/libvim

Is it better than (the AFAIK newer) https://github.com/asvetliakov/vscode-neovim ?

Seems like it's Vim with a VS Code extension/adapter instead.

Intriguing idea, though not sure how viable.

Took far too long for me to figure out that this isn't just a VS Code extension. I'm not even entirely sure this isn't.

No, likely out of diffidence onivim has a very similar design to VSC. It doesn't appear to share any code with VS Code though.

This isn't technically true, the extension host we use is directly the one from VSCode, such that we can support their extensions (well...a subset as we fill in the gaps in for the Oni2 <-> ExtHost communication).

But the actual core editor is all seperate, written in ReasonML (or OCaml if you know that instead), with a bunch of C libs in the background we've wrapped (Skia/Harfbuzz/We wrap real vim etc).

So the core editing experience has no code sharing, but the extension side of things does!