The code is here, you can build and run it right now.
Replying to this from Ladybird, which somehow doesn't exist but is able to both render and post comments to this page.
Ladybird very much exists. Been running it successfully in Linux for a while now.
I think they were referring to the version of Ladybird taking advantage of Swift v6. I agree in part that it is only nice idea until a production ready binary gets released; right now it is just experimental.