reference.html & selection.json

IcoMoon’s selection.js file now gets uploaded in addition to the other necessary files when you enable Quick Usage. The app would show two links, one for selection.json (which can be used in build tools), and one for reference.html. This reference.html is a dynamic page that lists the icons in your selection along with their class names. If you are using a paid plan, the link to this page does not change unless you rename your project. This lets teams share the link to the reference page as a cheatsheet for other team members who want to use the icon set.