SALT2.4 stretch (x₁) and color (c) light-curve parameters of SNe Ia from the SDSS, PS1, and SNLS samples of the Pantheon catalog. The individual SNe are shown as blue dots. The ellipse (x₁ = ±3, c = ±0.3) is displayed, colored by the corresponding standardized absolute magnitude using the α and β coefficients from Scolnic et al. (2018). The diagonal gray lines represent the (x₁, c) evolution for m = m_lim for z between 0.50 and z = 1.70 using the SNLS m_lim of 24.8 mag.