Switch 2 third-party games in Japan are Key Cards requiring further downloads

Pre-orders for Switch 2 games are open in Japan, and all the physical third-party titles listed so far use a format called Game-Key Card. This is a brand-new thing introduced by Nintendo that consists of a cartridge that does not contain the game data, but is just a key for a download via the eShop.
According to Nintendo, a Key Card does not contain the complete game, but allows it to be installed from the Internet. The game can then be launched via the cartridge, just like a classic physical version.
11 third-party games display the Game-Key Card logo on their cover, including Bravely Default: Flying Fairy, Street Fighter 6, Sonic X Shadow Generations and Yakuza 0: Director’s Cut. Only two Marvelous titles are the exception to this, but these are enhanced editions of existing Switch games.
At this stage, it has not been confirmed whether this approach will be generalized after launch, or whether it will also apply to Western versions. Note that Cyberpunk 2077 is expected to be fully contained on the cartridge.