The immutable flag to ensure browsers do not attempt conditional reload.
Immutable is an 'in-beta' Cache-Control flag supported by Chome, Firefox and Safari.
# and force cache headers on response
#
<Location /openlayers/img/404.png>
# and force cache headers on response
#
<Location /openlayers/img/404.png>
- Header always set Cache-Control "max-age=31536000"
+ Header always set Cache-Control "public, max-age=31536000, immutable"
Header always set Expires "Tue, 19 Jan 2038 03:14:07 GMT"
RewriteRule ^ - [G,L]
</Location>
Header always set Expires "Tue, 19 Jan 2038 03:14:07 GMT"
RewriteRule ^ - [G,L]
</Location>