nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
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
Open graph title entity tag
This page contains a meta robots tag which tells search engines and robots to index or not index the page.
By adding rel="home" to a hyperlink, a page indicates that the destination of that hyperlink is the homepage of the site in which the current page appears.