This format is used for Nintendo Switch digital packages. In an official capacity, these are handled automatically by the console's firmware.
It looks like you’re referencing a file name for a update (specifically Version 1.0.2, often labeled as Update 1 in certain communities). Pokemon-Lets-Go-Pikachu-NSP_Update-1___40_1__41...
While "Update 1" often refers to the first major patch, the final version of the game ended at v1.0.2 . If you are looking for the most stable experience with full compatibility for Pokémon HOME, ensuring you are on 1.0.2 is essential. This format is used for Nintendo Switch digital packages
Here is a quick breakdown of what that update addressed and what you should know about it: While "Update 1" often refers to the first
Addressed bugs where certain moves or stats didn't behave as intended during battle.
Improved the stability of local and online connections when trading or battling with other players. Important Context
Resolved an issue where Pokémon sent via Mystery Gift wouldn't be registered to the Pokédex if the game was closed improperly.