I haven't looked at it. I hope it's off by default. Private repos are ... private.
Discussion
I think it’s a profile setting and I agree it should default to off. I personally like it on just because I am just staring my programming career and would like to show that I’m actively using hit, but most of my contributions are to an organizational repo that is private due to IP protection. It’s a pretty narrow reason to broadly ruin privacy though…
No you have to disable it manually. At least for me it was activated by default.