cdnjs is a free distributed JS library delivery service.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
TinyMCE is an online rich-text editor released as open-source software. TinyMCE is designed to integrate with JavaScript libraries, Vue.js, and AngularJS as well as content management systems such as Joomla!, and WordPress.
Zendesk is a cloud-based help desk management solution offering customizable tools to build customer service portal, knowledge base and online communities.