When I try to get the list of organization projects, the private projects just don't show up - only public. I get an emply list since all of my projects are private. To test this, I made myself admin of a private project and was still unable to get json back for that project. Only when I mark a project as public does it give back some data.
(I also added the accept header for previewing projects)
What am I dong wrong here? How can I access these private projects?
Have you used one of the authentication methods mentioned in the documentation? If you don't tell GitHub who is asking, then it assumes that the person asking doesn't have the rights to see private stuff.
I hope that helps!