Transmission spectra in the region of the metastable He I triplet. Top: weighted-mean-averaged transmission spectrum for each observed transit. Bottom: weighted mean of the three observed transits. Vertical orange lines mark the position of the three components of the metastable He I triplet. Since the final error bars are calculated following error propagationby taking the square roots of the extracted spectra aligned in the telluric rest frame as initial errors, the final error bars correspond to one standard deviation.