proot-startscript-ubuntuamd64
The proot latest build (v5.2.0-alpha-8c0ccf7d) and a script to run rootfs of Ubuntu on amd64
Ubuntu Rootfs Images can be downloaded below:
https://mirrors.tuna.tsinghua.edu.cn/lxc-images/images/ubuntu/
When you untar rootfs.tar.xz ....
./proot --link2symlink tar -xpf ubuntu.tar.xz -C ubuntu/