Host intrinsic visual dust extinction A_V toward the line of sight of the GRB plotted against redshift for the GRBs analyzed in this paper and in comparison to different samples at mostly lower redshift (Covino et al. 2013; Greiner et al. 2011; Krühler et al. 2011a; Zafar et al. 2011a). The dashed lines represent the GROND detection thresholds for GRB 131117, 140311A, and 090423 in the given band (see Sect. 5). Highly extinguished GRBs are labeled. The red and purple dots represent 500 from the 10⁶ simulated (z, A_V(obs.)) pairs.