The primary graph in the platform is a Tukey mean-difference (Cleveland 1994, p. 130), which plots the difference of the two responses on the y-axis against the mean of the two responses on the x-axis. This graph is the same as a scatterplot of the two original variables, but turned 45 degrees. A 45 degree rotation and rescaling turns the original coordinates into a difference and a mean.
Example of Transforming to Difference by Mean, Rotated by 45 Degrees

Help created on 9/19/2017