Single-element Planck mean opacities for each species at t = 3.5 d, T = 6000 K, and ρ = 10⁻¹³ g cm⁻³ (upper panel), elemental abundances ejected in the sym-n1-a6 NSM model at t = 3.5 d (Just et al. 2023) (middle panel), and contribution of each element to the Planck mean opacities of the KN ejecta based on the composition resulting in model sym-n1-a6 model 3.5 days post-merger (lower panel). The total Planck opacity of the ejecta (i.e., the HFR Planck mean opacities for this ejecta composition summed over all elements Z) is found to be equal to 1.13 cm² g⁻¹, whereas an opacity of 1.43 cm² g⁻¹ is obtained when using the formula from Just et al. (2022).