Distribution of RRLs in the disc-like structure identified with the CLiMB algorithm in the E versus L_z (top-left), Cartesian Z versus X (top-right), and Z_max versus eccentricity (bottom-left) planes, colour-coded by metallicity. The black dashed line outlines the region used to select the thin-disc RRLs. Metallicity distributions of RRLs in the thin and thick discs, selected on the basis of their Z_max and eccentricity (bottom-right). See main text for details.