Excess dielectron $m_{\rm ee}$-differential yields after subtraction of the cocktail of known hadronic decay contributions in semi-peripheral (left) and peripheral (right) Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV, compared with calculations for coherent two-photon production of e$^{+}$e$^{-}$ pairs folded with the detector resolution. For details see the text. The error bars and boxes represent the statistical and systematic uncertainties of the data, respectively. Arrows indicate upper limits at 90\% confidence level.