Files with the .nsp extension are used by the Nintendo Switch system to install software. In the context of homebrew, they are often used with custom firmware like Atmosphere or emulators such as Ryujinx.
This specific version was a landmark "bonus update" that introduced significant content and technical enhancements: Splatoon 3 [0100C2500FC20800][v655360][US].nsp ...
: Specifies that this file is from the North American region . Files with the