Our current setup places Moodle behind an reverse proxy to prevent irregular access to the application server. HTTP 50X pages are replaced (using NGINX proxy_intercept_errors) ** with a generic error page to prevent information disclosure on any error.

Unfortunately this also prevents site admins from getting access to any error information as Moodle is not logging any information to PHP's error_log. It would be nice if even in non-debug mode fatal errors could be loggable to have a way to access these error messages.