If you must open it, do so inside a or a "sandbox" environment to protect your primary operating system.
Because .rar files are compressed archives, the exact content depends on the source you downloaded it from. However, based on common naming conventions in tech and gaming circles, it likely contains one of the following: KeywordsOP.rar
Upload the .rar file to VirusTotal to scan it against dozens of antivirus engines. If you must open it, do so inside