Posterior distributions of the interior structure of TOI-1803 b. We show the mass fractions of the inner core, mantle, and envelope layer as well as the mass fraction of water in the envelope. The different colors show three different priors for the planetary Si/Mg/Fe ratios, stellar (purple), iron-enriched (pink) and sampled uniformly from a simplex (blue). The top row shows the results when assuming a formation scenario outside the ice line, the bottom row is compatible with a formation inside the ice line. The dashed line shows the median of each distribution, while the priors are shown as dotted lines.