$ git clone -n https://src.fedoraproject.org/rpms/vtk.git /var/lib/mock/f42-bootstrap-3462996-45594/root/chroot_tmpdir/scmroot/vtk
Cloning into '/var/lib/mock/f42-bootstrap-3462996-45594/root/chroot_tmpdir/scmroot/vtk'...
$ git fetch origin 00e3473c3deb552f10a0f660852897760004bf9f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vtk
 * [new ref]         00e3473c3deb552f10a0f660852897760004bf9f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 00e3473 Remove obsolete FindHDF5.cmake