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.
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
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.