$ git clone -n https://src.fedoraproject.org/rpms/rpm-head-signing.git /var/lib/mock/f40-build-735036-106168/root/chroot_tmpdir/scmroot/rpm-head-signing
Cloning into '/var/lib/mock/f40-build-735036-106168/root/chroot_tmpdir/scmroot/rpm-head-signing'...
$ git fetch origin b161e10ff96d7124863b178f4860b17c2a656e49:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rpm-head-signing
 * [new ref]         b161e10ff96d7124863b178f4860b17c2a656e49 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b161e10 [packit] 1.7.4 upstream release