Charged-particle pseudorapidity density in Pb\==Pb~ and p\==Pb for the $5\%$ most central collisions, and for pp collisions with \INELGtZero{} trigger class. For symmetric collision systems (Pb\==Pb and pp) the data has been symmetrised around ${\eta=0}$ and points for ${\eta>3.5}$ have been reflected around ${\eta=0}$. The boxes around the points and to the right reflect the uncorrelated and correlated, with respect to pseudorapidity, systematic uncertainty, respectively The relative correlated, normalisation, uncertainties are evaluated at $\textdndeta|_{\eta=0}$. The lines show fits of \EqRef{eq:f} (Pb\==Pb and pp) and \EqRef{eq:g} (p\==Pb) to the data (discussed in Section~\ref{sec:discussion}). Please note that the ordinate has been cut twice to accommodate for the very different ranges of the charged-particle pseudorapidity densities.