Changes in the CMB TT spectrum and foreground spectra, between the best-fitting A_L model and the best-fitting base ΛCDM model to the Planck TT+lowP data. The solid blue line shows the difference between the A_L model and ΛCDM  while the dashed line has the the same values of the other cosmological parameters, but with A_L set to unity, to highlight the changes in the spectrum arising from differences in the other parameters. Also shown are the changes in the best-fitting foreground contributions to the four frequency cross-spectra between the A_L model and the ΛCDM model. The data points (with ± 1σ errors) are the differences between the high-ℓ maximum-likelihood frequency-averaged CMB spectrum and the best-fitting ΛCDM model to the Planck TT+lowP data (as in Fig. 1). Note that the changes in the CMB spectrum and the foregrounds should be added when comparing to the residuals in the data points.