Base File System

I am interested in creating my own base file system for the Beagleboard. In this minimal image: https://rcn-ee.com/rootfs/eewiki/minfs/debian-10.10-minimal-armhf-2021-06-20.tar.xz 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 https://github.com/RobertCNelson/omap-image-builder
cd ./omap-image-builder/
./RootStock-NG.sh -c project.file

Regards,