You have successfully logged on a Linux system. You want to now cover your track. Your login attempt may be logged on several files located in /var/log. Which file does NOT belong to the list:

wtmp is a valid binary log file in /var/log that records all successful logins and logouts, readable via the 'last' command.

Linux systems track login activity in specific standard log files: wtmp records successful logins, btmp records failed login attempts, and auth.log records authentication events including sudo and SSH. The file 'user.log' is not a standard or commonly present login-tracking log file in /var/log on most Linux distributions, making it the outlier in this list.

btmp is a valid binary log file in /var/log that records failed login attempts, readable via the 'lastb' command.

auth.log is a standard plain-text log file in /var/log on Debian-based systems that records authentication-related events including PAM, SSH, and sudo activity.