Inter-frequency foreground-cleaned TT power spectra differences, in μK². Each of the sub-panels shows the difference, after foreground subtraction, between pairs of frequency power spectra (the spectrum named on the vertical axis minus the one named on the horizontal axis), in units of standard deviation. The coloured bands identify deviations that are smaller than one (yellow), two (orange), or three (red) standard deviations. We show the differences for both the HM power spectra (blue points) and the DS power spectra (light blue points) after correlated noise correction. Figure 41 displays the same quantities for the TE and EE spectra.