HTTP caching can speed up your page load time on repeat visits. When a browser requests a resource, the server providing the resource can tell the browser how long it should temporarily store or cache the resource. For any subsequent request for that resource, the browser uses its local copy rather than getting it from the network.

The directives added to the .htaccess file directs the server to return the Cache-Control HTTP response header and uses the ExpiresByType to indicate what how long a resource should be cached by the browser.