Error estimates of cubature formulas exact for Haar polynomials in classes of two-variable functions satisfying a general Lipschitz condition

Upper error estimates are obtained for cubature formulas with the Haar $d$-property in the classes $\mathrm{Lip}(L_1,L_2)$ of two-variable functions satisfying a general Lipschitz condition. It is shown that the error of minimal cubature formulas possessing the Haar $d$-property have the best order of convergence to zero in the indicated classes.