This is the AUR of Jiangge Zhang.
sudo mkdir -p /etc/archlinux-repro
sudo vim /etc/archlinux-repro/repro.conf
The example content:
BOOTSTRAPMIRROR='https://geo.mirror.pkgbuild.com/iso/latest'
HOSTMIRROR='https://geo.mirror.pkgbuild.com/$repo/os/$arch'
ARCHIVEURL='https://archive.archlinux.org/packages'