It is a Roshal Archive compressed file. It bundles multiple files together and shrinks them to save space.
Always scan downloaded RAR files with antivirus software before extracting them. If you did not expect this file or don't know its source, be cautious about running any .exe files found inside.
if found on unofficial websites, as random "Setup" files in RAR format are sometimes used to distribute malware. Important Considerations for RAR Files