An anonymous member from Groove forum released this PS3 homebrew--PS3 K_License Extractor Python Script for PKG Files, let's have a look.
Download: PS3 K_License Extractor Python Script for PKG Files
Here is the quote: An anonymous developer has released a K_License Extractor for use on retail and debug PKGs.
The k_license is a unique license string generated and embedded in PSN and other PKG files. The script will retrieve and display this k_license when ran.
Please note the app is in the form of a python script and meant for experienced devs.