Comparison of MUSE spectra in the Ca II region of two eMSTO stars with a low value of vsini (target #44909, blue curve), consistent with no or slow rotation, and a high rotational velocity (target #43977, red curve). For both spectra, the black curves show the respective best-fit synthetic models. Note that the blue and red spectra are the same as those shown in Fig. 8, and correspond to the targets marked by the star symbols in Fig. 7, using the same color code.