Retrieved posterior probability distributions for the mixing ratios of prominent molecules, shown for the four cases using WFC3 and NIRSpec data, as described in Sect. 3. The horizontal error bars denote the median and corresponding 1σ interval for each distribution. The arrows in the case of H₂O, NH₃ and C₂H₆ indicate 95% upper limits. We infer CH₄, CO₂, and CS₂ at 4.9σ, 3.6σ, and 2.8σ significance, respectively, in the canonical one-offset case with non-grey limb darkening. Abundance estimates and detection significance for these cases are shown in Tables 1 and I.1.