Distribution of SALT2 stretch parameter x₁ (left panel) and colour parameter c (right panel) for all light curves with eight or more detections, for the sample of 2205 light curves that meet our criteria (black), and for the subset of 1383 that are spectroscopically confirmed SNe Ia in TNS (grey). Distributions of x₁ (left panel) and c are also shown from Taylor et al. (2021) using the Dark Energy Survey (DES) supernovae sample (blue line; taken from their Fig. 9), from Nielsen et al. (2016) using the Joint Lightcurve Analysis (JLA) sample (green; taken from their Fig. 1), and from Scolnic et al. (2022) using the Pantheon+ sample (orange).