cdnjs is a free distributed JS library delivery service.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
GSAP is an animation library that allows you to create animations with JavaScript.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.
WP-Optimize is an all-in-one WordPress plugin that cleans your database, compresses your large images and caches your site.
Yoast SEO is a search engine optimisation plugin for WordPress and other platforms.