Nintendo has clarified that Switch 2 Edition cartridges will contain both the original Switch version of the game in question and the Switch 2 upgrade, meaning you won't have to download anything extra to play them.
In a statement provided to Australian Nintendo news platform Vooks, Nintendo said that physical Switch 2 Edition games will "include the original Nintendo Switch game and its upgrade pack all on the same game card".
Nintendo goes on to say that "no download code" will be included in Switch 2 Edition packs and that the cartridges therein will be "exclusively Nintendo Switch 2 game cards". Good news if you were hoping to resell your Switch 2 Edition games at some point, or if your internet connection is spotty.

Frustratingly, however, Nintendo then says that "some publishers may release Nintendo Switch 2 Edition games as download codes in physical packaging" if they choose, and that such releases would contain "no game card".
In essence, then, first-party Nintendo Switch 2 Edition games will always contain both the original game and the upgrade code, but that might not be the case for third-party publishers. Caveat emptor, I suppose.
Just in case you've somehow missed the hubbub, the Nintendo Switch 2 was announced in full last week, with a worldwide release date of June 5th and a US price (for now, at least) of $449.99, jumping to $499.99 with a copy of launch title Mario Kart World.
Though the console is still on track to launch on June 5th, pre-orders have been delayed in the US and Canada due to President Donald Trump's sweeping economic tariffs. Nintendo also appears to be weighing up whether releasing the Switch 2 in China will be worth its while.
Games confirmed to be getting Switch 2 Editions so far include The Legend of Zelda: Breath of the Wild and Tears of the Kingdom, as well as Kirby and the Forgotten Land, Super Mario Party Jamboree, and Metroid Prime 4: Beyond. Not all of them are launching alongside the console, though.