nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
mod_pagespeed is an open-source Apache module that automatically optimizes web pages and resources on them.
The http-equiv attribute provides an HTTP header for the information/value of the content attribute. The http-equiv attribute can be used to simulate an HTTP response header.
This page contains a meta robots tag which tells search engines and robots to index or not index the page.