Detect the compression methods of Repackers ?

[aswadd]

Hello Guys
Basically for those who don't know how Just look at
C:\Users\youruser\AppData\Local\Temp when you are installing a repack
so If anyone want to share some methods For how to detect the compression method that some Re packers use like
R.G Catalyste & FitGirl Repack ..
I Tried [R.G Catalyse] they are using a complied bat file located in the temp Folder so i can't even know the pass of the arc files but i'm sure they are using a normal methods like precomp + Srep
For FitGirl I'm Sure she is using nanozip + Precomp but can't even know how to open her archives it always says the archive is damage run check to fix it so any one know methods pls share & we all will benefit