In cybersecurity competitions, "134rar" is often the name of a challenge involving or reverse engineering . A typical write-up for such a challenge would involve:
Identifying the file as a RAR archive using tools like file or binwalk . 134rar
If "134rar" is just a specific file you encountered, here is a general overview of RAR files : RAR - Википедия In cybersecurity competitions, "134rar" is often the name