Several cut-outs of illustrative parts of the normalized X-shooter UVB arm spectrum showing the presence of H lines. The regions have been chosen to have at least one strong transition of H and to be little affected by blending. The black lines show the data, red lines the best-fit model, and grey lines the residuals. Grey shaded regions are ignored in the fitting because of blending with metal absorption lines. In each panel we also give the best-fit χ², as well as the improvement Δχ² as compared to an unmodified spectrum.