It's sending the "wrong" one --
$ curl -I http://lcamtuf.coredump.cx/squirrel/
HTTP/1.1 200 OK
Date: Thu, 11 Aug 2016 05:18:00 GMT
Server: Apache
Last-Modified: Mon, 19 Sep 2011 23:31:49 GMT
Accept-Ranges: bytes
Content-Length: 135938
Content-Type: text/html