The extraction will produce a .pkg file, which is a game dump designed to be installed on a jailbroken PS4 console .
Use software like WinRAR or 7-Zip to extract the contents, starting with .part01.rar . BatmanArkhamKnightUSAPKG-pkgps4dotcom.part09.rar
If the extraction fails, this particular part ( .part09.rar ) may be corrupted, or another part is missing. The extraction will produce a
You must download all .part files (part01 through the last part) associated with this download to extract it successfully. BatmanArkhamKnightUSAPKG-pkgps4dotcom.part09.rar
Files from third-party PKG sites can contain errors or, rarely, malicious content. Ensure you have antivirus software active during extraction.