It's possible, Windows 98 has drivers for the NE2000 network card we're emulating (https://github.com/copy/v86/blob/master/src/ne2k.js). However, currently the emulation isn't accurate enough, Windows 98 refuses to use it.
This allows you to connect to CORS enabled sites without using the WebSocket proxy. It talks HTTP on the serial port.
I want to add SNI support to tlstunnel so that I can tunnel to google.com by navigating to https://google.com.mydomain/ and having the snitunnel tunnel to http://google.com by reading the bottom-level domain names using SNI.
Using this with browser-http-proxy, it would be possible to tunnel to HTTP sites on a request-based level (making it easier to scale) and without relying on tun/tap on the server. Also it could serve as a fallback for non-CORS enabled hosts.