1Ans ) We currently don't really have logs that track everything a user does.
Closest thing we have OOTB are the SingleSignOnAuditLog<DATE>.log files in the */sso/logs directory on PC.
We don't have complete Audit logging. Maybe some day in the future. We record login to SingleSignOnAuditLog.* files.
We also have an audit_log table where we log login/logout, and a few other things but not much. We have group change log (seen in admin UI) to track basic group changes via UI and by who.
2Ans ) When the first line is printed for a new Day, it creates a new file and appends until 23:59:59. I don't see a process that cleans up these files.