Polyfill is a service which accepts a request for a set of browser features and returns only the polyfills that are needed by the requesting browser.
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
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.