This is just a proof of concept for now
npm i
node index.js
This will load an html file, that's served by the built-in mocking mechanism.
This html will load an image which is served from the internet.
It'll also embed an iframe, which is mocked by msw.
If you already have handlers in msw, you can re-use them for your browser tests as well.
While you could use your handlers inside the browser instance, what they could do would be limited to the browser environment and the setup would be more complex as well. E.g. inside node, you can read the file system, do database queries etc.