Comparison of best-fit spectra for retrievals of the joint HST-JWST spectrum using different molecular absorbers and a grey cloud. The orange spectrum is the best-fit case from the model with the highest Bayesian evidence: a grey cloud and only H₂O and CO₂ as line absorbers. The light blue dashed spectrum does not include water as an absorber, whereas the light green dashed spectrum is without CO₂. The dark green spectrum is the best fit of the cloudy+CO prior model (see Sect. 4.5). As in Fig. 8, there is a vertical offset between the HST and JWST data.