$ git clone -n https://src.fedoraproject.org/rpms/quaternion.git /var/lib/mock/f39-build-1562688-37453/root/chroot_tmpdir/scmroot/quaternion
Cloning into '/var/lib/mock/f39-build-1562688-37453/root/chroot_tmpdir/scmroot/quaternion'...
$ git fetch origin f49b94a50503942e3b7346724f647bc7b389daa8:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/quaternion
 * [new ref]         f49b94a50503942e3b7346724f647bc7b389daa8 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f49b94a Fix file lists to account for REUSE style licensing