Comparison between theoretical transmission spectra computed with full NLTE (A; black; same as the black line in Figure 8), namely the NLTE TP profile and accounting for NLTE effects for the computation of the transmission spectrum (TS), and with partial NLTE (B, red), namely NLTE TP profile and assuming LTE for the computation of the transmission spectrum, at a resolution of 100 000 in the NUV and optical range. The bottom panel shows the relative difference between the two spectra in percent. In the top panel, the blue horizontal dashed line indicates the location of the Roche radius in the planetary limb direction.