Bitmap of the mixing matrices to model the theoretical signal for the pseudo-Cls as seen by KiDS-1000. On the right panel is the mixing matrix derived from the KiDS-1000 mask, M_{μν′,ℓℓ″}, (the input mask is at a resolution of N_side = 1024). On the left panel is the mixing matrix caused by the selection due to randomly sampling galaxies for the auto-correlation of the fifth tomographic bin, $M_{\nu \prime \nu ,\ell ″\ell \prime }^{\prime (55)}$. Both matrices are decomposed into block matrices separating the EE → EE, EE → BB and EB → EB mixing. Each block matrix has dimensions of 8193 × 8193 with ℓ ∈ {ℓ∈ℤ⁰⁺|ℓ ≤ 8192}.