Custom PHP Script Log

Summary

How to log vars from Agent Console / File Manager / PHP custom script

Content

Hi There,

I've noticed in some of the PHP scripts located in the Agent Console File Manager / Custom Scripts there are instances of "_log(var_name)" function.
For instance: _log("Incident found: " . $incident->ID);

those were written by other developers and I wonder where this function logs to.

I've looked in the Agent Console under Site Configuration / Logs and nothing is being written to any of the  log categories (error, info, security, etc...)

With that said:

Is it the correct / best way to log a custom PHP script?