Peak Luminosity L_p versus FWHM_min for the Swift/BAT Type-II GRB sample (red circles). The colour-coded density map is the result of a simulated sample of Type-II GRBs that accounts for the selection effects shown in Fig. 8 under the assumption of no correlation between L_p and FWHM_min. For comparison, we also show SGRBs (cyan circles). Gold dashed lines represent loci with constant isotropic-equivalent released energy of each individual peak, approximately calculated as E_iso = L_p FWHM_min.