title: XHR2 withCredentials - which cookies are sent?
body: <p>Hopefully this is simple to answer.</p>
  
  <p>With a credentialed request in XHR2, which cookies are sent?</p>
  
  <p>I've been following <a href="https://developer.mozilla.org/en-US/docs/HTTP/Access_control_CORS?redirectlocale=en-US&amp;redirectslug=HTTP_access_control#Requests_with_credentials" rel="nofollow">the MDN article on credentialed requests</a>, and it shows that the cookie <code>pageAccess=2</code> is sent with the request. However it doesn't explain where that cookie comes from, and why that cookie specifically is being sent. Is it simply that all cookies set by the page are sent in any credentialed request?</p>