Base-ΛCDM model (A_L = 1) TT power spectrum residuals smoothed with a Gaussian kernel of width σ_ℓ = 40. The black line shows the smoothed difference between the coadded data points and the theoretical model for the Planck TT+lowE best-fit model, while coloured lines show the residuals for samples over the allowed parameter space coloured by the value of Ω_mh². Grey bands show the 1, 2, and 3σ diagonal range expected for the smoothed residuals in the best-fit model. The red dashed line shows 10% of the lensing-smoothing difference predicted in the best-fit model, displaying the oscillatory signal expected if there were more lensing of the acoustic peaks. The data residuals are not particularly anomalous, but the residuals have a similar pattern to the lensing smoothing difference over the approximate range ℓ = 1100–2000, giving a preference for around 10% more lensing at fixed cosmological parameters. Allowed models with lower Ω_mh² (and hence higher H₀) predict less lensing and give a larger oscillatory residual, preferring relatively more lensing smoothing than models with high matter density. The black dashed line shows the smoothed residual for the Planck TT+lowE best fit to ΛCDM+A_L (with A_L = 1.19).