If this file is a mod pack, it usually requires a "mods" folder within the directory. Some users recommend renaming this folder (e.g., adding a "z" at the start) to manage loading priority [2].
Users often use these files to install custom content or specific game states:
The .rar extension indicates a compressed archive. Note that official versions are typically distributed through the Steam client; .rar files found on third-party sites are often associated with unofficial distributions or mods [2, 3]. System Requirements
Content is typically extracted into the main game directory found via Steam > Manage > Browse local files [2, 3].
Specific files can also be used to import custom garage layouts by placing data files into the App Data folder [6].