Top left: mixing coefficient profiles D_mix (full lines) as a function of normalized radius when varying the overshoot parameter f_ov in the 3 M_⊙ reference model. Dashed vertical lines indicate convective core boundaries r_cc, obtained from the Schwarzschild criterion (e.g., Kippenhahn et al. 2012). Top right: density ρ (dotted lines) and radial magnetic field component B_r profile (at θ = 5°; full line) for the same stellar model. Dashed vertical lines indicate the same as on the left. Bottom row: same as Fig. 4, but varying f_ov.