I'm working on "Mafia The Old Country"
I found that:
For *.pak oodle kraken core_2.9.10 lib_2 and maybe ue4 (better ratio with)
but for *.ucas seems to be encrypted => no compression ratio
here a sample
https://mega.nz/folder/3kwS2LaA#7q_kcF1WkgZYFgn8RxJ5YQ