I have an html page with the following code.
<form method="POST" action="https://formspree.io/email">
<input type="submit" value="SEND"/>
</form>
My browser does not include the referrer header field in the http request when a user submits the form. Why wouldn't it ?
I fixed this by adding <meta name="referrer" content="origin">
to the <head>
section of my HTML page.