For general discussion there is a mailing list. It is used for general Gio announcements and questions.
It’s a good place to interactively discuss different topics.
Once in a month, or so, there is a community call with different topics. Usually there is an update to the project, a talk by someone from the community and discussions of different problems that people are facing. The events are announced on the mailing list.
You can find recordings of the previous events on Youtube.
Gio source can be found at:
To help out and contribute to project check out contribution guide.