$ git clone -n https://src.fedoraproject.org/rpms/expat.git /var/lib/mock/f42-build-side-1-3501731-45976/root/chroot_tmpdir/scmroot/expat
Cloning into '/var/lib/mock/f42-build-side-1-3501731-45976/root/chroot_tmpdir/scmroot/expat'...
$ git fetch origin 43428492fb6765c9d02565b8167c65309d62e6ff:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/expat
 * [new ref]         43428492fb6765c9d02565b8167c65309d62e6ff -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4342849 Rebase to 2.7.1