This is not an official Sony service . It requires a modified console. Using it may violate terms of service and can lead to a PSN ban if connected online. Many PKG stores are no longer actively maintained, but some archives exist via community sites.
Once you have access to a PKG store or have downloaded a file to a USB drive (formatted to FAT32), the installation process is straightforward: ps3 pkg store
bucanero/pkgi-ps3: A PlayStation 3 package download tool - GitHub This is not an official Sony service
In the context of the PlayStation 3 (PS3), a file is the installation package format used by Sony for games, updates, DLC, and system software. A "PS3 PKG Store" is not an official Sony service . Instead, it refers to third-party homebrew applications that run on a modified (jailbroken or custom firmware) PS3, allowing users to browse, download, and install PKG files directly from online repositories. Many PKG stores are no longer actively maintained,