[SpaghettiX]

Exactly, the website is misleading. It's not a rendering engine in any way. That slogan already contradicts the title: "Render in flutter". Is it "rendering using Flutter" or is "rendering it itself"? The answer is you don't render with Flutter at all, Flutter uses Skia for Native (everything except web), and "Kraken" does that again, but purely because it builds a Flutter app.

It also seems not to be high performance either, judging by exikyut's comment.