It is similar to the recently released PS3 PKGView and UnPKG file extractors / unpackers, and to use it simply click the big button and select your PKG file.
To quote, roughly translated: "There is a similar procedure before the call PkgView.exe But the program can not bulk unpacked, unpack and often wrong.
The device can be quickly unpacked all the files once unpacked. Self-made program can only unpack and debug pkg. Can not unpack the pkg downloaded from the official PSN."
Stay tuned for more PS3 Hacks and PS3 CFW news, follow us on Twitter and be sure to drop by the PS3 Hacks and PS3 Custom Firmware Forums for the latest PlayStation 3 scene updates and homebrew releases!
Thanks for submitting this xbox1080, since it just does what people can do from their Web browser with this guide though I am just adding jeffma's PS3 Game Update Finder v1.1 to the first post here vs a new thread.