EE, BB, and EB power spectra of the CMB computed on 50% of the sky with the PR4 maps at low (left panels) and intermediate multipoles (right panels). The Planck 2018 ΛCDM model is plotted in black. Grey bands represent the associated cosmic variance. Error bars are deduced from the PR4 Monte Carlo simulations. Correlations between data points are given in Appendix D. A simple χ² test shows no significant departure from the model for any of these spectra.