Apache 2.4.10 |Operating System:Debian

   The Apache HTTP Server, colloquially called Apache, is free and open-source cross-platform web server software, released under the terms of Apache License 2.0. Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

PHP 5.6.38-0+deb8u1

   PHP: Hypertext Preprocessor is a general-purpose programming language originally designed for web development.

Cache-Control Header Max-Age

   Specifies the maximum amount of time a resource will be considered fresh. Contrary to Expires, this directive is relative to the time of the request. this website is having max-age=60 secs.

Vary Header Accept-Encoding

   The Accept-Encoding request HTTP header advertises which content encoding, usually a compression algorithm, the client is able to understand. Using content negotiation, the server selects one of the proposals, uses it and informs the client of its choice with the Content-Encoding response header.

Character Encoding :UTF-8

   This website is using UTF-8 character encoding in HTML , character encoding is used to represent a repertoire of characters by some kind of encoding system.