Comparison of the timescale of the He II flash-ionisation feature versus the peak absolute magnitude (left panels) and the rise time (right panels), for various SNe (adapted from Bruch et al. 2023). Top panels are in the g band while bottom panels in the r band. SN 2022lxg is shown as a star, where the filled or empty markers denote two potential timescales (8.24 and 11.63 days respectively; see Sect. 3.3.1. The filled circles are a sample of SNe showing flash-ionisation features taken from Bruch et al. (2023).