Ask HN: Open-source, free pair-programming tools?

Hello!

What are the best open-source, free pair-programming tools out there?

I'm doing collaborative code development & coaching - the students often don't have credit cards or accounts on platforms like Google, Microsoft etc.

We're using VSCodium code editor, and programming web apps with Python (Django, perhaps an API framework lile FastAPI/DRF) HTML, React, Typescript, SQlite, etc.

Commercial tools I'm aware of: Pop.com (free), Tuple (paid), VSCode Live Share (free, required Microsoft/GitHub account), Jitsi (video conference tool, but I don't think it has screen control)

Looking for high quality, open/free equivalents...