FAILED - (No max-age or expires) - https://itst.net/wp-includes/images/rss.pngAlbeit, the resource is served with:
< Last-Modified: Sat, 26 Oct 2013 17:28:46 GMT
< Accept-Ranges: bytes
< Content-Length: 608
< Cache-Control: public
< Expires: Sat, 30 Jun 2018 15:39:36 GMT
See this for reference.
What am I doing wrong? Is this a bug or a feature? 
Thanks
Sascha