X-shooter spectra of VHS 1256−1257 b (black) compared to the best-fit ATMO model (red). Residuals from the best fit are shown at the bottom of each panel. The fit is provided between (A) 1.10 and 2.48 μm; (B) 1.225 and 1.275 μm, a zoom around the K I doublet is shown here; (C) 2.28 and 2.41 μm, a zoom around the CO overtones is shown here; and (D) 2.90 and 4.14 μm. (E) 0.65–2.48 μm is the fit evidencing the model departure at optical wavelengths which are only shown here.