Core compactness ξ_2.5 (panels a–c), iron core mass M_Fe (panels d–f), and central specific entropy s_c (panels g–i) as a function of the CO core mass M_CO at core collapse. As in other figures, we distinguish between Cases A–C accretors, and colour-code the mass accretion fraction f_acc. Accretion fractions of 25%, 75%, and 200% are connected by dashed lines to better visualise trends and systematic shifts.