Websites using some form of Captcha technology on them.
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
The DOCTYPE is a required preamble for HTML5 websites.
Websites using https protocol.
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.
Wesites using favicon rel tag