Distribution of average redshift (green tiles) for the blazars used to create the locus. We see that the regions dominated by FSRQs (i.e., top-right corners of both panels) have higher average redshifts (z_av). The dark-blue numbers within each tile represent the total number of sources used to compute the average redshift, while the brown numbers represent the number of blazars with unknown redshift. Tiles with no redshift available are set to 0 and tagged with the label “No z”, while the background tiles are set to −0.5. The black contours represent the 90% containment projections of the blazar locus in both mid-infrared color-color planes.