$ git clone -n https://src.fedoraproject.org/rpms/x11docker.git /var/lib/mock/f45-build-38550-725/root/chroot_tmpdir/scmroot/x11docker
Cloning into '/var/lib/mock/f45-build-38550-725/root/chroot_tmpdir/scmroot/x11docker'...
$ git fetch origin 5d5a9747bf645ce53c9b0318399aa62bdd926c29:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/x11docker
 * [new ref]         5d5a9747bf645ce53c9b0318399aa62bdd926c29 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5d5a974 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild