Official Files: Since the PKGs come from Sony, they are untouched and "clean" from a data integrity standpoint.
PKG Files: These are the standard encrypted packages used by the PS3 to install games, updates, and DLC. ps3 nopaystation
To use NoPayStation content on a PS3, your console must be running Custom Firmware (CFW) or PS3HEN. Stock consoles cannot use RAP files to activate "unsigned" content. The Desktop Client (NPS Browser) Official Files: Since the PKGs come from Sony,
The most popular way to use the service is through the NPS Browser for Windows or macOS. Stock consoles cannot use RAP files to activate
If you're looking for more specific help with your PS3 setup: Information on installing vs PS3HEN Troubleshooting RAP file activation errors How to use NPS Browser on mobile or Linux
Preservation: NPS serves as a digital archive for titles that may eventually be delisted from the official store.