The main project repo is on Github, where you can also find out how to contribute. We also have a guide available about writing new python modules. Do keep in mind, though, that we are moving to Go modules. These are the two types of orchestrators that we use for developing new data collection modules (or data collectors) for Netdata.
We also have our monthly contributor awards available on Github. We are planning to move those here in the near future.
Pull requests are always welcome! If you are considering contributing or helping out with a Netdata module or the Netdata agent or if you are developing your own project that integrates with Netdata, we would love to hear from you!