Development contribution

I think the local live TV needs help, so I’m interested in contributing to the Plex Media Server and Plex Media Player source code.

What all is open source if anything? Is there quick start or crash course on the history of the project and/or the layout and hierarchy?

How can I contribute to improving the local live tv tuner functionality?

Plex Media Server and Plex clients are all closed-source (outside of the no-longer-supported Plex Media Player, and even older Plex Home Theater).