Binned Hubble residuals (corrected for stretch and environment) vs. colour. The error bars on the points only account for the error on the mean, but a visual indication of the fitted intrinsic scatter is given in the top left corner. The full line is the usual Tripp relation, and the dashed line is the fitted broken-β standardisation. The open points represent the Hubble residuals corrected for stretch using the broken-α standardisation found in Ginolin et al. (2024).