Google APIs are application programming interfaces developed by Google which allow communication with Google Services and their integration to other services.
This site uses the viewport meta tag which means the content may be optimized for mobile content.
Using this tag you can set up your web app to have an application shortcut icon added to a device's homescreen, and have the app launch in full-screen "app mode".
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
Chrome for Android, since version 39 supports the "theme-color" meta tag to allow websites control the background color of the tab's UI header.
Sites who has this tag are verfied by google to use WebMaster tools
Meta descriptions are HTML attributes that provide concise explanations of the contents of web pages. Meta descriptions are commonly used on search engine result pages (SERPs) to display preview snippets for a given page.
Open graph description entity tag
The Open Graph protocol enables any web page to become a rich object in a social graph, a open protocol supported by Facebook
Google's hosted library for web fonts. Allows websites to choose and use fonts from a free, wide variety of fonts.