$ git clone -n https://src.fedoraproject.org/rpms/system-rules.git /var/lib/mock/f39-build-1568327-37629/root/chroot_tmpdir/scmroot/system-rules
Cloning into '/var/lib/mock/f39-build-1568327-37629/root/chroot_tmpdir/scmroot/system-rules'...
$ git fetch origin 70f75766a49ee9e87115e249609ae107431ff07b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/system-rules
 * [new ref]         70f75766a49ee9e87115e249609ae107431ff07b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 70f7576 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild