The two have played together for five years now, and as we have all seen, Tavares is proud of the steps Matthews has taken over that time.
With the core four seemingly intact for the coming season, the Leafs Stanley Cup window remains officially open, and after taking a major step forward this past season, it appears they're ready for another one.
Matthews extension keeps him in Toronto for the near future, and while the future of the remainder of the team remains uncertain, with him locked in, they'll always be competitive, so this seems to be a win all around for the Leafs.