Which apache/httpd (root or www-data) user, who load /etc/php.ini when webserver startup?

I want to secure my php ini access right.

We know that apache/httpd master process, is owned by root. Then it spawn new child process in www-data user.

If /etc/php.ini loaded by apache as root user, I want to limit read access of php.ini to root only.

So, Which apache/httpd (root or www-data) user, who load /etc/php.ini when webserver startup?