Plot of CARMS values vs. declinations for 295 ICRF2 defining sources (blue crosses), 39 ICRF2 special handling sources (black triangles), and 296 ICRF3 defining sources (red circles). There are seven ICRF3 defining sources missing because they have fewer than 10 closure amplitudes available. Extremely extended sources have unfortunately been included as defining sources in both ICRF2 and ICRF3 due to lack of structure indices derived from VLBA observations and the need to fill defining sources in the southern sky for a uniform distribution, as shown with red circles and blue crosses in the upper-left corner. About 21% of ICRF3 defining sources have CARMS values larger than 0.4.