It's a little unclear, but I think he wants to integrate Python (Pyodide) coroutines into the JS event loop-- so async/await of Python code works seamlessly in

It's a little unclear, but I think he wants to integrate Python (Pyodide) coroutines into the JS event loop-- so async/await of Python code works seamlessly in the browser, and you can await Python code from within JS (and vice versa). Any JS Promise is awaitable from JS; JS async/await is (more or less) syntactic sugar on top of promises.