Shown are three sets of MESA evolutionary models: with v_ini = 0 km s⁻¹ and B_ini = 0 kG (red solid lines), v_ini = 90 km s⁻¹ and B_ini = 0 kG (grey dashed lines), and v_ini = 90 km s⁻¹ and B_ini = 6 kG (black dotted lines). The 14 sample stars are colour-coded according to their measured magnetic field strengths as purple (> 4 kG), white (< 2 kG and < 4 kG), and yellow (< 2 kG). The stellar mass in solar units is indicated next to the tracks on the right panel. In this mass range, both (moderate) rotation and surface fossil magnetic fields lead to small effects, leading to closely overlapping evolutionary tracks.