The blog specifically states "this does not involve WebAssembly", so it seems like this uses Blazor Server and not Blazor WebAssembly, meaning that it doesn't run any .NET code in the browser space at all. While this is also very new, it's an officially supported part of ASP.NET Core 3.0. I'd probably not use Blazor Server in a web app just yet since it requires an active connection to the web server, but this is all local so I'm pretty interested in trying it out.

Of course this is still an experiment so it's very risky to use it, but it's cool and shows promise.

Edit: Looks like maybe this thread is talking about using Blazor at all instead of within the context of the post, but I what I said still applies so I'll leave it up.

There is no reason it couldn't run a wasm file? As long as the OS browser supports it.

I feel like this is the UI abstraction layer. If you want to run chromium, there is no reason you couldn't extend it.

Code is prime for extending and enhancing.