Effect of the [Fe/H] calibration for a few example open and globular clusters. Each panel shows the observed Gaia DR3 colour-magnitude diagrams (G vs G – G_RP), colour-coded by either xgb_met (left panels) or feh_calibrated (right panels). The colour code limits are different in each row to highlight the differences with respect to the respective literature [Fe/H]. Top row: The solar-metallicity open cluster M67 (NGC 2682). Middle row: The metal-poor open cluster NGC 2158. Bottom row: Bulge globular cluster NGC 6752.