Most of the news/blogs websites include RSS feeds link in their header. For example:
<link rel="alternate" type="application/rss+xml" title="Example Feed" href="http://example.com/feed/" />
I want to know what is the practical use of adding above? Is it to tell the browser that the website has RSS feeds? In past Firefox has the button in the address bar, but now they have remove it. Also if some user want to subscribe the RSS, he needs to enter the feeds url directly. So where it is being used? Thanks
Yes, it is to tell anything consuming the page (e.g. a browser) that there is an alternative form of the content elsewhere.
Most browsers used to all have an RSS button that would light up if it saw this, to allow you to subscribe to the feed.
RSS has (arguably) dropped in popularity, so this is less common today by default in browsers. But extensions and so on will still use it.
Or indeed, if you add a “normal” url to something like Google Reader, it will fetch that page, and look for an rss link in the head tag, to find the final feed url.