Significance K_p – V_rest maps for the tested chemical species: H₂O, CH₄, NH₃, C₂H₂, HCN, CO, CO₂, and H₂S. Each K_p – V_rest map shows the significance of the cross-correlation signal of the GIANO-B spectra (4 transits combined) with isothermal atmospheric models, as a function of the planet’s RV semi-amplitude (K_p) and the planet’s rest-frame velocity (V_rest). The significance is computed with a Welch t-test on two samples of cross-correlation values, that is, far from and near to the planet’s RV respectively (see the text for more details). The vertical and horizontal white dashed lines correspond to V_rest = 0 km s⁻¹ and the expected K_p value (${\hat{K}}_{\mathrm{p}}$), respectively.