Not all errors are reported by users so it is important that these are captured by the system automatically. This allows developers to look through errors logs and fix issues in the next version of the software.
The main error handling routines are in /include/custom_error_handler.inc which is required within /include/staff_student_auth.inc. This means any page using authentication has the automatic error handling pre-setup.
Errors are recorded in the sys_errors table which can either be inspected directly through MySQL by developers or through 'Administrative Tools' interface by SysAdmin users.
Important
Some open source partners include error details in their tickets and emails. The variable section can include user passwords which obviously should not be passed around. For this reason there is a check in the log_error() function for 'ROGO_PW' and if it is set the $post_data is set to <hidden>.