Field of view (FoV) of the Kepler mission is respresented by the solid black squares. It is centered at RA = 19° 22 40.0, Dec = +44° 30 00.0, between the Cygnus and the Lyra constellation. The FoVs of the sixteen 3XMM-DR5 observations we analyzed (Table 1) are reported as red circles; the red numbers represent the 3XMM-DR5 unique observation ID (OBS_ID). The FoVs of some XMM-Newton observations are totally or partially overlapping.