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
