$ git clone -n https://src.fedoraproject.org/rpms/plank.git /var/lib/mock/f45-build-28578-631/root/chroot_tmpdir/scmroot/plank
Cloning into '/var/lib/mock/f45-build-28578-631/root/chroot_tmpdir/scmroot/plank'...
$ git fetch origin 34b1c4632b5e4cdb6c6eaa783064e8d3e238109a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plank
 * [new ref]         34b1c4632b5e4cdb6c6eaa783064e8d3e238109a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 34b1c46 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild