Emails logging isn't working.
In UI is settings "Email log: Log all outgoing email messages", but it has no effect.
In code this settings is used only in lib-warnings.inc.php, however this file contains only one function which is never called in code. Also lib-warnings.inc.php is never included in code.
1. Depends on Product decision: - logging emails is lack of functionality or log emails setting should be removed from code
2. Review and remove unused lib-warnings.inc.php from code base.