cdnjs is a free distributed JS library delivery service.
Google Tag Manager is a tag management system (TMS) that allows you to quickly and easily update measurement codes and related code fragments collectively known as tags on your website or mobile app.
GSAP is an animation library that allows you to create animations with JavaScript.
Open Graph is a protocol that is used to integrate any web page into the social graph.
OWL Carousel is an enabled jQuery plugin that lets you create responsive carousel sliders.
PHP is a general-purpose scripting language used for web development.