Before anything, MiniBox is an experimental project for me.
MiniBox will prepare a Linux kernel to run BusyBox through an initrd script. It's a kind of fun project that helps people explore things and learn about the Linux Kernel and BusyBox's capabilities. At least for me, it's fun :)
If you want to learn more about it, it's enough to clone it and run it, or you should spend a bit of time to read the miniBox.sh script.