Version of the game (Mortal Kombat (2011))

I began to notice that there are different versions of the game due to the DLC program Manager 2.6 beta,ie in the program we will find a ready skin Rhine Char_Rn_S.xxx.diff and ini files,why did I think this version is different because there are 2 types of files for example Char_Rn_S.xxx and Char_Rn_S.xxx.diff(format xxx and diff) and still want to learn this all means that there is a version of the game with the files of diff format?