: Expiry date in response header contradicts the cache-control setting I have set up a very long expiry on some files in my .htaccess (this is OK as I change the actual filename whenever its

I have set up a very long expiry on some files in my .htaccess (this is OK as I change the actual filename whenever its content changes).

<FilesMatch "min_d+-d+-d+-d+-d+-d+.css$|min_d+-d+-d+-d+-d+-d+.js$">
Header set Cache-Control "max-age=31536000, public"
</FilesMatch>

Looking at the output of Firebug, the cache-control is getting passed through, but I notice that the 'Expires' in the response is set to 25th May (14 days in the future rather than 1 year as it aught to be). Does anyone have any ideas what is going on?

Request Headers

Accept text/css,*/*;q=0.1
Accept-Encoding gzip, deflate
Accept-Language en-US,en;q=0.5
Connection keep-alive
Host redacted.co.uk
Referer redacted.co.uk/hh/main_minimised/ User-Agent Mozilla/5.0 (Windows NT 6.1; WOW64; rv:20.0) Gecko/20100101 Firefox/20.0

Response Headers

Accept-Ranges none
Cache-Control max-age=31536000, public
Connection Keep-Alive
Content-Encoding gzip
Content-Length 5576
Content-Type text/css
Date Sat, 11 May 2013 22:46:47 GMT
Expires Sat, 25 May 2013 22:46:47 GMT
Keep-Alive timeout=5, max=99
Last-Modified Sat, 11 May 2013 17:12:31 GMT
Server Apache
Vary Accept-Encoding