Transmission signals for the planets with He I detections (black dots with error bars labelled in blue) and some planets with upper limits (black arrows labelled in orange), as a function of the stellar (λ = 5–504 Å) at the planet distance. TOI-560 b, WASP-80 b, and 55 Cnc e flux values were computed up to λ ~ 912 Å. We show the equivalent height of the He I atmosphere, , normalised by the atmospheric scale height, H_eq, of the respective planet. The red star is the results presented here on GJ 1214 b. Data on other planets are from Nortmann et al. (2018); Alonso-Floriano et al. (2019); Palle et al. (2020); Kasper et al. (2020); dos Santos et al. (2020); Paragas et al. (2021); Casasayas-Barris et al. (2021); Zhang et al. (2021, 2022); Fossati et al. (2022); Czesla et al. (2022).