[Fe/H] values from spectroscopic published works versus the [Fe/H] values inferred by the GSP-Phot and GSP-Spec module. The red filled circles are data points located in the areas A and B of the Luminosity–T_eff diagram of Messineo & Brown (2019). Encircled data points are from the works of Davies et al. (2010) and Gazak et al. (2014). Left panel: [Fe/H] values from the literature versus those inferred from GSP-Phot module. Middle panel: [Fe/H] values from the literature versus the [M/H] values inferred from GSP-Spec. Right panel: [Fe/H] values from the literature versus the [Fe/H] values inferred from GSP-Spec [M/H] and GSP-Spec [α/Fe] using the formula of Ferraro et al. (1999).