Use 7-Zip (open source) or WinRAR to extract the contents.
While there is no single official document titled "," files with this naming convention typically appear in enthusiast forums, 3D modeling repositories, or diagnostic software archives. MiniCooper_5.rar
Before opening the archive, identify the most likely content based on the website where you found it: Use 7-Zip (open source) or WinRAR to extract the contents