If you are looking for a paper about the concept of RAR rather than a file, you might be referring to one of these common academic acronyms:
A machine learning technique to prevent "catastrophic forgetting" in AI models. See the paper from the NeurIPS Conference . data.rar
How underwater biological growth affects the efficiency of vibration-based power systems. 4. Technical Definitions of "RAR" in Papers If you are looking for a paper about