Observations from MIRI of 55 Cancri e (black markers, Hu et al. 2024), including the MIRI shadow region (orange markers), compared to a selection of synthetic emission spectra (coloured and grey lines). The blue shaded area indicates the range of spectra that matches the observation, based on a χ²-fit (excluding the shadow region). Three endmembers within the set of matching models are highlighted: the best fit (black, Ψ_VMF = 0, ΔIW-6 and ξ = 0.5), a mineral-rich He–H₂–CO–SiO–atmosphere (minC, bright blue, Ψ_VMF = −1, ΔIW-6 and ξ = 0.1), and a waterworld (WW, dark blue, Ψ_VMF = 1, ΔIW+6 and ξ = 0). Relevant non-fitting models are shown in grey and comprise the gas-dwarf scenario (GDw, Ψ_VMF = 1, ΔIW-6 and ξ =0) as well as a reduced (rBSE, Ψ_VMF = 0, ΔIW-3 and ξ =1) and an oxidised VIBSE scenario (oBSE, Ψ_VMF = 0, ΔIW+3 and ξ = 1).