Scatter plot of position differences in right ascension and declination (Gaia minus ICRF2). Top left: all 2191 sources. Top right: the 2069 sources within ± 10 mas in both coordinates. Bottom left: the 1742 sources within ± 3 mas in both coordinates. Bottom right: the 1069 sources within ± 1 mas in both coordinates. Symbols show defining sources as blue squares, non-VCS sources as red crosses, and VCS-only sources as grey plus signs.