title: How to set custom $_SERVER variables from client in PHP
body: <p>According to this post: <a href="https://stackoverflow.com/questions/6474783/which-server-variables-are-safe">Which $_SERVER variables are safe?</a> and another I've seen, a client seems to be able to set custom $_SERVER variables. For example: $_SERVER['HTTP_EXAMPLE']</p>
  
  <p>How would a client actually set a value to $_SERVER['HTTP_EXAMPLE']?</p>