The File System Access API is useful for opening a local .ipynb and .csv with JupyterLite, which builds CPython for WASM as Pyodide.
There is a "Direct Sockets API in Chrome 131" but not in FF; so WebRTC and WebSocket relaying is unnecessary for WASM apps like WebVM:
https://news.ycombinator.com/item?id=42029188
> wasi-io, wasi-clocks, wasi-random, wasi-filesystem, wasi-sockets, wasi-cli, wasi-http