Similar to Fig. 18. The X-ray afterglow light curves of 64 LGRBs plus 32 SGRBs (taken from Bernardini et al. 2012; Lü et al. 2015) are shown as a 2D histogram, while several individual transients are overplotted: GRB 111209A (ultra-long duration LGRB; solid magenta line, z = 0.677; Levan et al. 2014); GRB 170817A (off-axis SGRB, multiplied by ×1000; solid dark green line; Nynka et al. 2018; D’Avanzo et al. 2018; Troja et al. 2020, 2022); SN 2020bvc (the first off-axis LGRB candidate; solid light green line; Izzo et al. 2020), and theoretical off-axis GRB afterglows at different viewing angles θ_obs (solid and dashed colour lines represents afterglows with isotropic-equivalent energy and circumburst density of 10⁵³ erg, 1 cm⁻³ and 10⁵¹ erg, 0.15 cm⁻³, respectively; Berger 2014; Ryan et al. 2020; Chrimes et al. 2022). For FXTs 15, 17, 18, and 20 (open symbols), we assume z = 1.0, and for FXTs 16, 19, 21, and 22, we take the redshift values from Table 6.