Top panel: Comparison of the ISW kernel, defined as the product of cosmic expansion and growth, for all the 791 GS simulations (grey). We again highlight simulations 401 (yellow), 742 (green), and 127 (dark blue), as representatives of different w values in the GS parameter space. Bottom panel: Our results from the fiducial TheoryCL pipeline and pyCCL compared to alternative computations using CAMB and approximate f(z) formulae described in Section 2.3. This panel highlights the excellent agreement between our pipeline and pyCCL.