Similar to Figure 3, the plots show the same scaling relations, but with the color bar now indicating the logarithm of the efficiency of ICL production in dark matter halos. The efficiency is defined as the ratio between the ICL mass and the halo mass. A clear trend emerges in both panels: stellar halos tend to be more massive when the efficiency of ICL production is higher. In the left panel, this appears at fixed BCG mass, where redder colors correspond to more massive stellar halos, while in the right panel the trend follows the main relation itself.