Distributions of net counts for the Main (0.2–2.3 keV; left panel) and Hard (2.3–5 keV; right panel) catalogues. Point sources (EXT = 0) and extended sources (EXT > 0) are plotted in blue and orange, respectively. Point sources with any SP flag (see Table 6) are displayed as blue shaded histograms. The sources that appear in both the Main and the Hard catalogues are plotted in red in the left panel.