The string is not a standard software feature or a recognized command. Based on its structure, it is most likely a password for a protected RAR archive or a specific serial key/activation code for software .
If you found this string alongside a RAR file, try using it as the . @j2#gr5bb@@ rar
: Many files downloaded from forums or file-sharing sites use complex strings like this as the "unlock" password. The string is not a standard software feature