Outskirts’ mass fraction as a function of redshift. Gray dots represent the data, while gray contours illustrate their distribution at 0.25, 0.5 and 0.75 levels. The median is shown as a purple circle, with each point computed in bins of Δz = 1. Vertical error bars indicate the standard deviation, while horizontal bars represent the width within each bin. Red stars refer to the LRDs also in Kocevski et al. (2025).