As I say on the FAQ page, all of it uses open source software, and you can SSH onto the box and see it. I don't open source the methods of installing and configuring it because that's the whole business. This is no different than you buying a flashed router from anywhere else, could always be spyware in your hardware.

Right, especially if you are selling it as something to maintain privacy, I'd like to see the source code.

It uses vanilla OpenWRT. The app to configure it is just react native and speaks OpenWRT API's. The only thing I could open source are 1) How I flash the router and configure it, which is a hassle and I'm not going to share, and 2) The source code to the react native app, which you can decompile and look at if you want.

If you want to see the open source of the router software itself, go to https://openwrt.org/ and dive in

Being able to see source code and certifying the binaries running on the machine are not the same thing.