Median difference in abundance ratios between the bulge of M31 and stacked spectra of ETGs for different elements, as shown on the x-axis. Median values and error bars are derived from different models and fitting methods (see the text). Different elements are color-coded as in Fig. 4. Empty and filled symbols denote ETGs with low- (σ = 150 km s⁻¹) and high- (σ > 260 kms) velocity dispersions, respectively, as indicated in the lower-left corner. The horizontal dashed line marks a difference of zero, while the vertical dotted line separates the α-elements (left) from the remaining ones (right).