Average feature importance in the cINN for the primary stellar properties. Shown is the median relative contribution of each flux bin to the total gradient of each target parameter with respect to the total flux vector averaged over a synthetic test set with S/N=250 Å⁻¹. Black lines indicate flux bins whose median contribution is larger than the mean by more than 3 σ. In each row, the left panel shows the green 4MOST window, while the right panel presents the red window. The dashed lines in the log (g) and [Fe/H] panels indicate common diagnostic absorption lines of various elements that coincide with a peak in the feature importance.