Applications that need to make direct TCP/UDP connections to things, but which you want to run in the browser and don't want to rely on a centralised websockets

Applications that need to make direct TCP/UDP connections to things, but which you want to run in the browser and don't want to rely on a centralised websockets proxy or other hacks. Endless use-cases for this. Servers, games, collaboration tools, clients for non-HTTP protocols (email, gopher, Gemini etc), file sharing. You name it.