Transmission spectrum of WASP-127b and retrieved models. The blue circles and black squares with error bars are the observed spectrum by NOT/ALFOSC and GTC/OSIRIS, respectively. This spectrum shows an enhanced slope at the blue optical, strong absorption peaks at 589.3 nm, 670.8 nm, and 768.2 nm, and another bump at the red optical. These features can be explained by the model spectrum when including opacities resulting from haze, Na, Li, K, and H₂ O, respectively. The red curve shows the retrieved median model while the shaded areas show the 1σ and 2σ confidence regions. The yellow diamonds show the binned version for the retrieved median model.