You can use tools like NSC_Builder (Nintendo Switch Cleaner and Builder) to verify the file's hash and digital signature against known legitimate copies.
A common safety practice is to test the file first in an emulator like Ryujinx on a PC before installing it on an actual Switch. Installation Context Sea of Stars (NSP)(DEMO).rar
A report for the file indicates it is a compressed archive containing a Nintendo Submission Package (NSP) for the demo of the turn-based RPG Sea of Stars . File Details Game: Sea of Stars (Demo version). You can use tools like NSC_Builder (Nintendo Switch
This file is typically used on Nintendo Switch consoles with custom firmware (CFW) using installers like Goldleaf or DBI . Note that the demo was officially released for free on the Nintendo eShop, which remains the only 100% safe method for acquisition. File Details Game: Sea of Stars (Demo version)
The .rar is a container; the internal .nsp is the standard digital format used for Nintendo Switch games and emulators.