The server may set this optional response header to change the browser location after a fragment update.
Without this header Unpoly will set the browser location to the response URL, which is usually sufficient.
When setting X-Up-Location it is recommended to also set X-Up-Method. If no X-Up-Method header is given
and the response's URL changed from the request's URL, Unpoly will assume a redirect and set the
method to GET.
Internet Explorer 11
There is an edge case on Internet Explorer 11, where Unpoly cannot detect the final URL after a redirect.
You can fix this edge case by delivering X-Up-Location and X-Up-Method headers with the last response
in a series of redirects.
The simplest implementation is to set these headers for every request.
Example
X-Up-Location: /current-url
X-Up-Method: GET
