Standardised Hubble residuals (α = 0) as a function of stretch (x₁). Large blue points show the data binned by stretch (mean) while the red hexagons show the binned stretch for SNe Ia from locally red environments. The errorbars on the binned points only display the error on the mean, but a reference for the fitted intrinsic scatter σ_int is plotted in the top-right corner. The blue line shows the best fitted broken-α model, while the dashed grey line shows the best α when assuming the linear Tripp relation.