How to access pokedex entries for Max Lair Legendary Pokemon?

So, something that I’ve noticed when playing the Crown Tundra DLC for Pokemon Sword and Shield is that many of the Legendary Pokemon (particularly those Legendary Pokemon you catch in the Max Lair) don’t seem to have pokedex entries listed in the Crown Tundra Pokedex. However, when I go onto a wiki like Bulbapedia and check the articles for these pokemon, they’re usually listed as having pokedex entries for Sword and Shield. For instance, Necrozma isn’t listed in the Crown Tundra Pokedex, but his Bulbapedia page lists his Sword and Shield Pokedex entries.

Is it possible to access these pokedex entries in-game, or were the pokedex entries listed on the wiki datamined out of the game data without accessing the actual in-game pokedex?