Here's a step-by-step guide to extracting PKG files using the PKG Extractor tool:
Plug your USB drive into your PC. Create a folder structure exactly like this on the root of the drive: \PS3\ (Note: The folder name must be in all caps). pkg extractor ps3
Extract PKG → find .msg or .bin localization files → translate strings → reinject using a custom PKG builder. Here's a step-by-step guide to extracting PKG files