$ git clone -n https://src.fedoraproject.org/rpms/marshalparser.git /var/lib/mock/f38-build-side-42-init-devel-590906-26137/root/chroot_tmpdir/scmroot/marshalparser
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-590906-26137/root/chroot_tmpdir/scmroot/marshalparser'...
$ git fetch origin 0759bc18196c98b01fcc5c51a062d8d986b34fd5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/marshalparser
 * [new ref]         0759bc18196c98b01fcc5c51a062d8d986b34fd5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0759bc1 Update to 0.3.4 (rhbz#2179370)