Comoving matter-density angular auto-spectrum in a single shell at z = 0.7 (red) and z = 1.8 (pink) in ΛCDM cosmology. The cross-spectrum between two shells at z = 0.7 and z = 1.8 is shown in green. Left: spectrum from the RAYGAL 2500 deg² light cone (diamonds with error bars) and the spectrum from CLASS (dashed line). We note that the CLASS prediction for the cross-spectrum is not visible since it is oscillating around zero with a small amplitude, reaching at maximum 10⁻¹⁰ at ℓ = 30. The RAYGAL cross-spectrum is also oscillating around zero but with a larger amplitude (very likely due to sample variance), thus explaining the missing points, which are negative (or smaller than 10⁻⁹). Right: relative deviation from the CLASS prediction. The cross-spectrum is nearly zero in real space, and the relative deviation is therefore outside the graph, with very large error bars (that are omitted for readability). Overall, we find a good agreement for the auto-spectrum, except at large scales (small ℓ) due to the finite area of the light cone.