Continuum-normalized line profiles. Upper panel: Lyman α and smoothed, scaled Hα (see text for details). Inset: zoom-in on Lyα, with the theoretical absorption profile for τ_LyC = 1 superimposed. Middle panel: selected low-ionization metal absorption. Colored markers show the approximate expected position of fluorescent emission lines, color coded by their corresponding resonant line, with lengths indicating the average error spectrum in a velocity range of ± 1500 km s^-1 around the line. Lower panel: Si iv. Colored markers show the average errors, but are placed at arbitrary wavelengths. Metal lines are smoothed by 3 px. Gray dotted lines denote continuum level (horizontal) and velocity zero point (vertical). Pale dashed lines show regions masked out due to contamination.