Collimated parameters of GRB 210905A (red symbols) compared to a KW sample of 43 long GRBs from Tsvetkova et al. (2017, 2021). We assumed η = 0.2 and n = 1 cm⁻³ for all bursts. Left: half-opening angle θ_jet versus redshift. The dashed line within the grey area shows the relation found in Lloyd-Ronning et al. (2020a) with its error. Right: E_γ − E_peak, z diagram. As in Fig. 7, the colour of each data point represents the burst’s redshift. The ‘Ghirlanda’ relation is plotted together with its 68% and 90% PIs.