X-ray afterglow of GRB 210905A (blue line) in the context of other high-redshift GRBs (green and red) and the world-sample of Swift GRBs with known redshifts (grey density plot). The afterglow of GRB 210905A is the most luminous after 10 ks among all z > 5 GRBs and one of the most luminous in general. The colour table on the right side translates a grey shade at a given luminosity and time into a fraction of bursts.