The "System Log" link in the admin area of OTRS shows the last log entries of the system.
Each line in the log contains a time stamp, the log priority, the system component and the log entry itself.
The system logs are only available via the web interface on linux or
unix systems. On Windows systems you can see the log by opening the file
[install_dir]otrs\var\log\otrs.log
with a text editor.