Look for a file named script.js or similar within the folder. :
Right-click K9FATALI3.rar and select "Extract to K9FATALI3/". : K9FATALI3.rar
If you have verified the file is safe and intend to use it for single-player or private testing: : Use a program like 7-Zip or WinRAR . Look for a file named script
The file is widely associated with Minecraft modding , specifically as a "hacked client" or "cheat pack" often used in the 2D version (Paper Minecraft) or older community-shared versions . K9FATALI3.rar