Earlier quoted context omitted.
Good question. I searched around, but could only find this about Repl.it being closed source -- https://repl.it/feedback/p/open-source
That answer is a bit outdated because we open-sourced one of the core pieces of our infra: Prybar https://github.com/replit/prybar We'll be open-sourcing some more. As for how Multiplayer is implemented, we'll be doing a blogpost on it soon.
Sorry to be the license police, but I think that the attribution for embedding another project like that is a little unfair to the original authors, especially since this project is the more restrictive GPL 2.0.
https://softwareengineering.stackexchange.com/questions/2183...
"The fourth paragraph says that the copyright notice in the second paragraph must be reproduced. Users of the license [sic] substitute the [fullname] with their actual name. That is what constitutes "proper attribution" in the mind of the MIT: every user of the software can find out who wrote it if they want to."