If a website or an email prompts you to download a sitemap in a .rar format, it is likely a social engineering tactic: What Is a Sitemap | Google Search Central | Documentation
Downloading a "Site Map" as a file is highly unusual and often serves as a red flag for potential security risks. While a standard sitemap is a simple text or XML file used by search engines to crawl a website, the use of a compressed archive like RAR for this purpose is frequently associated with malware delivery or phishing. Understanding Sitemaps vs. RAR Files
RAR is a compression format used to group multiple files into a single, smaller package. Because RAR files can hide executables and other malicious scripts, they are a preferred tool for cybercriminals to bypass basic security filters. Why "Download Site Map rar" is a Major Risk