File created by Twig, a PHP optimizing template engine; contains a template that will be generated into a specific final format, such as a HTML, JavaScript, XML, or CSS based file; the twig extension determines what engine should be used to create the final format whether it's the Twig or PHP engine.

The Twig application creates more concise syntax than normal PHP, which makes the TWIG files more readable. Twig has two types of syntax: {{ ... }} - Prints a variable or the result of an expression to the template. {% ...%} - A tag that controls the logic of the template; used to execute statements. NOTE: The Symfony PHP framework uses Twig as its default template engine.