I successfully extracted all the game files from the PKG using PSN PKG Decryptor Extractor v1.85 and now I have these files:
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GameArchives is compatible with PS2 and PS3 versions of the game, but whenever I try to extract the ARK files I get an error: "Could not load archive! Given file was not a supported format."
I'm using GameArchives 0.11.2 since is the lastest available on Github. I know there are newer versions on AppVeyor, but are not available since they get deleted after 6 months or something (lastest version is 0.12.0.52 and was released more than a year ago, so).