Polarization and magnetic properties of the Mg I b₂ Stokes V classes. From left to right: Representative profiles V_R (blue) and mean class profiles (red), with shaded areas indicating the range of variation of the profiles within the classes; histograms of the |B_LOS| distribution from the SIR inversions (black) and from the WFA applied to the core of the Mg line (green); the photospheric to chromospheric |B_LOS| ratio; and the amplitude (orange) and area (maroon) asymmetries. Letters in column 1 and frame colors highlight different families.