Impact of the mass uncertainties on the retrieval for different scenarios of heavy N₂-dominated secondary atmospheres represented by increasing values of μ (2.3 in green, 5.2 in orange, 7.6 in magenta, and 11.1 in cyan). Blue line highlights the true value. The points alongside the boxes highlight the MAP (maximum-a-posteriori) parameters obtained for each analysed case. The size of the box and the error bar represent the points within 1σ and 2σ of the median of the distribution (highlighted with solid lines), respectively.