$ git clone -n https://src.fedoraproject.org/rpms/expat.git /var/lib/mock/f40-build-2663478-67004/root/chroot_tmpdir/scmroot/expat
Cloning into '/var/lib/mock/f40-build-2663478-67004/root/chroot_tmpdir/scmroot/expat'...
$ git fetch origin 3a5da2151cb0e9170ec384e9e82aba31e1e5bcec:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/expat
 * [new ref]         3a5da2151cb0e9170ec384e9e82aba31e1e5bcec -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3a5da21 Rebase to version 2.6.2