Diagonal contributions to the covariance matrix composing the model of Eq. (12). The red, green, and blue lines represent the three terms of the Gaussian covariance, and the yellow line is the non-Gaussian term. The comparison is shown for two different mass thresholds: a low-mass threshold M_th = 1 × 10¹³ M_⊙ in the top panel, and a high-mass threshold M_th = 1 × 10¹⁴ M_⊙ in the bottom panel. The terms are obtained by evaluating the covariance model at the input cosmology in the redshift bin z = 0.8 − 1.2.