Dominant contribution (absolute value) to the band power covariance. The colour coding is identical to Fig. 10, i.e. sample variance (red), mixed term (orange), and shot/shape noise (yellow) in the Gaussian covariance; non-Gaussian in-survey covariance (purple, always sub-dominant) and super-sample covariance (green); and the multiplicative shear bias uncertainty (grey). The top left block contains the covariance of the GGL signals (𝒞_nϵ; without cuts in tomographic bins or angular scales), the bottom right block the cosmic shear covariance (𝒞_E). Smaller blocks discernible correspond to the different bin combinations, and within these, individual 8 × 8 blocks correspond to the eight band powers of the signal for a single tomographic bin combination.