Maximal rms of reconstruction residuals for E modes (green), B modes (orange), and combined E and B modes (blue) determined from purified-inpainting simulations as a function of sky fraction. The red circle and the thin dashed lines show the reconstruction quality within the common polarization mask used in reconstruction (77.7% of the sky admitted, maximum rms combined residual of 9.0 μK). The blue star and the thin solid lines show the reconstruction quality within the confidence mask (64.8% of the sky admitted, with a maximum rms combined residual of 0.5 μK).