Illustration of possible variations in f_δ(k, z) reconstructions (68% CIs about the median) using τ = 5.0 and N_k = 20 on noisy data vectors from the ray-traced KiDS-1000 mock-data which has f_δ ≈ 1 (Sect. 5.5). There is a tendency for f_δ > 1 in Z₃ = [0.6, 2] (cyan), and a tendency for f_δ < 1 in Z₂ = [0.3, 0.6] (green) due to skewed PDFs and correlated errors. The magenta region shows the constraints for Z₁ = [0, 0.3] which are the tightest compared to Z₂ and Z₃. An average over many reconstructions is shown in the bottom panel of Fig. 6.