Apps that link to your content can then use this metadata to deep-link into your app, take users to an app store to download the app, or take them directly to the web to view the content.
PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.
Open graph description entity tag
The average rating based on multiple ratings or reviews.
Meta Keywords are a specific type of meta tag that appear in the HTML code of a Web page and help tell search engines what the topic of the page is.
This page contains a meta robots tag which tells search engines and robots to index or not index the page.
Sites who has this tag are verfied by google to use WebMaster tools