: Often refers to the "Base" game (as opposed to an update or DLC) and the "NSP" file format, which is the standard format for digital Nintendo Switch software.
This filename is likely:
Indicates this is the first segment of a multi-part WinRAR archive. You will need all subsequent parts (part2, part3, etc.) in the same folder to successfully extract the contents. Important Safety and Security Considerations csrnswtchbasenspeshopzipertopart1rar