: The specific file name you provided ( SMB35-NSwTcH-[BASE]-NSP ) is a digital backup (NSP format) found on ROM-sharing sites like Ziperto. These files are typically used by the homebrew community to preserve the game or attempt to play it on unofficial private servers, as the official version is no longer accessible. Preservation and Controversy
The "story" of this file is one of digital preservation. Because Nintendo "deleted" the game from history, enthusiasts use these NSP files to archive the software. However, since the game relied entirely on Nintendo's servers, the base file alone is essentially a "brick" unless paired with community-made server emulators. SMB35-NSwTcH-[BASE]-NSP-(eShop)-Ziperto.rar
: Nintendo intentionally made the game available only until March 31, 2021. After that date, the game was removed from the eShop and its servers were shut down, making it unplayable even for those who had previously downloaded it. : The specific file name you provided (