“The advent of WebAssembly and new capabilities APIs made it seem possible to write a WebAssembly-based operating system powerful enough to run Node.js, entirely inside your browser.”
StackBlitz built an operating system in WebAssembly so Node can run in a browser tab. The pitch is security: code stays in the sandbox and can’t touch your machine. The catch is the browser. It launched on Chrome first, and the business model is an enterprise license. Your dev environment now belongs to a vendor and a browser engine.