Échelle diagrams of mock g-mode spectra perturbed by rotation and magnetic field. Left: Spectrum fitted with an asymptotic expression accounting for magnetic and rotational perturbations, folded by the true ΔΠ₁. Right: Spectrum fitted with an asymptotic expression for rotation only, folded by the measured ΔΠ₁′. The red lines represent the slope of the m = 0 component, which is purely vertical on the right. The blue area represents the area where m = 0 modes are expected to be found using ϵ_g = 0.28 ± 0.08.