Final selection criteria for extended sources, from the preliminary version of the eSASS pipeline, with optimal (low-contamination) parameters. The extent–extension log-likelihood plane is shown for the three simulated sky fields: equatorial (top), intermediate (middle), and (deep) (bottom). Left panels: simulated (and detected) clusters are displayed as green dots, spurious extended detections as red triangles, and AGNs classified as extended sources in blue squares. Middle panels: only input detected galaxy clusters are displayed (green diamonds in the left panels). The distinct colours show the different simulated core radii (in arcsec). Right panels: only input detected galaxy clusters are displayed. The different colours show the distinct simulated input fluxes (in units of erg s⁻¹ cm⁻²).