Top left: cumulative distribution function (bottom) and histograms (top) of the isotropic γ-ray energy (E_iso) for the three classes of afterglow optical flux and based on a population of 76 GRBs with a redshift. Top right: same caption for the isotropic γ-ray luminosity (L_iso) based on a population of 73 GRBs with a redshift. Bottom left: same caption for the intrinsic peak energy (E_pi) based on a population of 76 GRBs with a redshift. Bottom right: same caption for the rest-frame burst duration (﹩{T}_{90}^{\mathrm{rest}}﹩) based on a population of 76 GRBs with a redshift. All panels: the faint GRBs are represented with a blue dotted line, the intermediate GRBs with a black dashed line, and the bright GRBs with a red solid line.