KFS is a user-mode file system application that provides a read-only “view” of original AFS content, combined with files from “patch” directories (called “roots”). This allows for simple run-time patching of game content, while leaving the original AFS files unmodified.
AFS files are basically containers that encapsulate smaller content pieces (also called bins or files). These files typically have “.afs” or “.img” extension and can be found in many games developed by Konami, including Winning Eleven and Pro Evolution Soccer.
https://bitbucket.org/juce/kfs/ (Git repository)
Kitserver File System (KFS) Copyright(c) 2012 juce