$ git clone -n https://src.fedoraproject.org/rpms/vtk.git /var/lib/mock/f40-build-760676-121131/root/chroot_tmpdir/scmroot/vtk
Cloning into '/var/lib/mock/f40-build-760676-121131/root/chroot_tmpdir/scmroot/vtk'...
$ git fetch origin 669f31d92649c2adbd7695111003c9a5ff3cb352:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/vtk
 * [new ref]         669f31d92649c2adbd7695111003c9a5ff3cb352 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 669f31d Rebuild (gdal)