Comparison of the X-ray fluxes in the training set and the complete catalog. The solid blue and red lines show the flux distributions of all eRASS1 and eRASS:4 sources, while X-ray fluxes of the eRASS1 and eRASS:4 training set are shown by the dotted blue and red lines, respectively. For the dashed red histogram, the eRASS:4 training set sources are weighted (see text for details). All distributions are normalized to the number of sources in the sample.