Evolution of the hydrogen mass fraction X as a function of the mass fraction inside the star for: three GENEC models with an initial mass of 32.8 M_⊙, overshooting parameter 0.20, Z = 0.015, and ξ = 1; the single version (blue) and the binary version (green) with initial rotational velocities of v_eq,ini = 100 km s⁻¹; and the single version (violet) with zero initial rotational velocity (v_eq,ini = 0 km s⁻¹). Two Clés models with an initial mass of 32.8 M_⊙, α_ov = 0.20, Z = 0.015, and ξ = 1 – one without turbulent diffusion (pink) and one with D_T = −2.41 × 10⁷ cm² s⁻¹ (orange) – are also presented for comparison. All models have a central fraction of hydrogen X_c of 0.2.