Unpacking the contents using WinRAR or 7-Zip to find a "flag" file (e.g., flag.txt ). 2. Gaming: "RAR" Mechanic
If "134rar" is just a specific file you encountered, here is a general overview of RAR files : RAR - Википедия 134rar
Identifying the file as a RAR archive using tools like file or binwalk . Unpacking the contents using WinRAR or 7-Zip to