Forum:UPK help

Hello. I use a simple program called extract.exe to extract content from upk files. However, files are decompressed but I ask for pro modders to explain me how to open the files : .Package and .ItemDefinition ones.

An example : If you unpack gd_currency, there are 3 text tables, five .Package files and one folder by Package file which every contains various but illisible files (I mean with a classic text editor).

Any help is welcome.