If you specify your own output buffering handler, it is present in the profile dump. If you call ob_gzhandler from your own handler, php:ob_gzhandler will be present as well.

<?php
ob_start('ob_ownhandler');
function ob_ownhandler($buffer, $mode)
{
if (strlen($buffer) <= 128)
{
return false;
}
return ob_gzhandler($buffer, $mode);
}
?>

The above will list both ob_ownhandler and ob_gzhandler in the output.