$ git clone -n https://src.fedoraproject.org/rpms/linux-atm.git /var/lib/mock/f45-build-17404-498/root/chroot_tmpdir/scmroot/linux-atm
Cloning into '/var/lib/mock/f45-build-17404-498/root/chroot_tmpdir/scmroot/linux-atm'...
$ git fetch origin 6acab13b3bdb7bcbef3b157d1f45f0dd8be1f0a5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/linux-atm
 * [new ref]         6acab13b3bdb7bcbef3b157d1f45f0dd8be1f0a5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6acab13 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild