Most favourable atmospheric chemical models. Top-left panel: HAT-P-11 b atmospheric temperature-pressure profile corresponding to the most favourable chemical-equilibrium model that shows spectral features from all the detected species, including the tentatively detected ones (Model 1: [M/H]=2.0, C/O=0.9, N/O=0.85, β_irr=0.5; solid line) and to a grid model modified including NH₃ vertical quenching at the 10 bar level (Model 2: [M/H]=1.7, C/O=0.59, N/O=0.14, β_irr=0.5; dashed line). Bottom-left panel: volume mixing ratios of the dominant chemical species (see legend) as a function of the atmospheric pressure corresponding to Model 1 (solid lines) and to Model 2 (dashed lines). Right panels: theoretical transmission spectra of HAT-P-11 b for atmospheres in thermochemical equilibrium (top-right panel) and with NH₃ quenching (bottom-right panel). The coloured curves show the contribution to the synthetic spectra of the four species detected by GIANO-B, including the tentatively detected ones (see legend). The black curve shows a lower-resolution (R = 500) spectrum combining the absorption from all atmospheric species in the model.