Luminosity fraction in the dynamically cold disks in cluster galaxies according to TNG50 at the present day. We show the luminosity-weighted cold-disk fraction of galaxies within 1R_e (left) and within 2R_e (right), whereby the effective radius is obtained at z = 0. We color code the markers by the time since infall, according to the color bars. Red, yellow, and blue curves and shaded regions denote population medians and 1σ variations of the stellar cold-disk fraction in bins of present-day galaxy stellar mass for ancient, intermediate, and recent infallers, respectively.