Distributions of all properties used in the classification, for the reference sample of 4XMM-DR10, and their KDE. From top to bottom, from left to right: galactic latitude (b), the four hardness ratios (HR1, HR2, HR3, HR4), index of the power-law fit, X-ray variability ratios, and X-ray to other wavelength flux ratios for the optical bands b and r and the infrared bands W1 and W2. The y axis is in arbitrary units.