Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
FullCalendar is a full-sized drag and drop JavaScript event calendar.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Moment.js is a free and open-source JavaScript library that removes the need to use the native JavaScript Date object directly.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.