Orbital period–luminosity diagram of the donor stars in our models following stable mass transfer with effective temperatures in the range of 4000 − 8500 K, colour-coded by initial primary mass. Panel (a) corresponds to the solar metallicity grid, and panel (b) to the metal-poor grid. For those models that do not exhibit constant luminosity after mass transfer, the lines depict the variation in luminosity as the model traverses the effective temperature range, with the markers denoting the time-weighted average of the corresponding evolution. Different markers denote the type of post-mass-transfer donor: post-RGB, central He-burning, post-AGB, or pre-subdwarf (pre-sd).