This is the name of the "scene group." DUPLEX is a famous release group known for cracking and releasing PS4 games for modified consoles.
If you have been browsing PlayStation 4 homebrew or modding forums, you have likely stumbled upon highly specific filenames. One common example floating around is . Download Darius Update PS4 DUPLEX CUSA20683 pkg rar
This is the specific Title ID for the game. Every PlayStation game has a unique region code. CUSA20683 identifies the exact region (e.g., US, Europe, or Japan) and version of the game. This is the name of the "scene group