Base File System

I am interested in creating my own base file system for the Beagleboard. In this minimal image: there’s a file image-builder.project. Am I correct to assume that there’s an application which takes it as an input and produces the contents of armhf-rootfs-debian-buster.tar? If so, what is that application?

This project will take that input:

git clone
cd ./omap-image-builder/
./ -c project.file