Mean forward model from one of our two fiducial interior-atmosphere joint retrievals, JR6, of WASP-80 b. This model corresponds to a core mass fraction (CMF) of 0.02, an atmospheric metallicity of M/H = 2.75 × solar, C/O = 0.12, and T_int = 134 K. Panel a: schematic cross section of the planet; layer thicknesses are to scale. The atmosphere corresponds to pressures below 1000 bar. Panel b: P–T profile of the atmosphere (light blue) and interior (blue and teal). Panel c: transmission spectrum for this model, with the three observed transmission datasets shown for comparison. Panel d: emission spectrum for this model, compared against the four observed emission datasets. Panel e: interior metal mass fraction profile (Z; black) and H/He mass fraction as functions of normalized radius. The atmospheric region (P < 1000 bar) is indicated in light blue. Panel f: atmospheric mass mixing ratios of the molecular species comprising the metals (P < 1000 bar). The region highlighted in orange indicates the pressure range probed by emission spectra, as calculated from the contribution function.