I have found an entry in html file
'<form action="?" ... '
It uses the current URL with an empty query string as the action of the form. An empty query string. Empty. Meaning no query string at all. The query string will be no more. It will not be used. It will be gone. There will be no more query string after submitting the form. The query string will have vanished. Disappeared. Gone away. Become no more.