$ git clone -n https://src.fedoraproject.org/rpms/initial-setup.git /var/lib/mock/f38-build-712635-94225/root/chroot_tmpdir/scmroot/initial-setup
Cloning into '/var/lib/mock/f38-build-712635-94225/root/chroot_tmpdir/scmroot/initial-setup'...
$ git fetch origin 86c3621a5813e3c58865a976d4de7137c81c75a8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/initial-setup
 * [new ref]         86c3621a5813e3c58865a976d4de7137c81c75a8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 86c3621 new version