$ git clone -n https://src.fedoraproject.org/rpms/xmount.git /var/lib/mock/f45-build-38980-731/root/chroot_tmpdir/scmroot/xmount
Cloning into '/var/lib/mock/f45-build-38980-731/root/chroot_tmpdir/scmroot/xmount'...
$ git fetch origin 235b770a7df4b7f42e94f131d3429ce07a9e3a2c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/xmount
 * [new ref]         235b770a7df4b7f42e94f131d3429ce07a9e3a2c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 235b770 update to 1.3.1