Mass-metallicity relation for unbound outflows in the first radial interval of the CGM (green circles), for the expelled mass rates (orange circles), and for the star-forming gas (purple circles) for each analysed galaxy. Solid lines are only included to facilitate the visualisation. Observations from Lee et al. (2006, leftwards-pointing triangles) and simulations from Christensen et al. (2018, black squares) are shown. The MZR relation by Tremonti et al. (2004) scaled to solar values of Lodders (2019, dotted line) is shown in dashed black line. The 16-84 percentiles (dark grey contours) and the 2.5–97.5 percentiles (light grey contours) scaled from Tremonti et al. (2004) are also displayed.