Posterior plots for all hyperparameters connected to the variation in z_p in m₁ are shown. The dashed lines denote the one-dimensional priors in the one-dimensional plots on top. The two-dimensional posteriors are shown in the corresponding row and column for the hyperparameters. Hyperparameters in this figure include the ascending power-law index α_z, the four hyperparameters connected to varying z_p via Eq. (2), and the difference between the high- and low-redshift value of z_p.