Only open it if you were expecting a large data export (e.g., from a university portal or a corporate SAP system).
In higher education, a "RAR" is a comprehensive document used to evaluate a university's performance. Volume-II reports often include extensive data on curriculum, research, and infrastructure.
There are documented instances of "huge reports" being downloaded in .rar format from SAP GRC AC (Governance, Risk, and Compliance) systems. If this file came from a corporate SAP environment, it likely contains audit or compliance data.