Sharpness of inner and outer slopes as a function of distance from the host star. The slopes are measured with a double power law or triple power law (α_in and α_out), while the central radii are measured with a double power law (R_c) or multiple Gaussians (R). For discs with multiple rings, only the innermost ring is plotted on the left and only the outermost ring is plotted on the right; for discs with halos, only the main planetesimal belts are plotted. This is due to the limitations of power-law parametrisations. The colours indicate the age of the system (Table A.2 in Matrà et al. 2025), while the marker shapes indicate the resolution of the ARKS observations (Table 2 in Marino et al. 2026). Discs with median power-law indices greater than 15 - the cut-off for pure planet sculpting of the inner edge - are indicated by arrows for both plots. We note that the x-error bars on the steepest discs are too small to be seen.