$ git clone -n https://src.fedoraproject.org/rpms/firecracker.git /var/lib/mock/f39-build-1931506-43112/root/chroot_tmpdir/scmroot/firecracker
Cloning into '/var/lib/mock/f39-build-1931506-43112/root/chroot_tmpdir/scmroot/firecracker'...
$ git fetch origin ee35c0f9c3247087504ab2e18faaf36a0499a81d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/firecracker
 * [new ref]         ee35c0f9c3247087504ab2e18faaf36a0499a81d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ee35c0f Update to version 1.5.1