cdnjs is a free distributed JS library delivery service.
Contentful is an API-first content management platform to create, manage and publish content on any digital channel.
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.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Mailchimp is a marketing automation platform and email marketing service.
Mapbox GL JS is a JavaScript library that uses WebGL to render interactive maps from vector tiles and Mapbox styles.
Mapbox.js is a JavaScript library provided by Mapbox for working with interactive maps and geospatial data.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Ruby on Rails is a server-side web application framework written in Ruby under the MIT License.
A modest JavaScript framework for the HTML you already have.