As you may know, Firefox 57 comes with a new user interface, known as "Photon". It is intended to provide a more modern, sleek feel that’s consistent across multiple platforms. It replaced the previous "Australis" UI and features new menus, a new customization pane and tabs without rounded corners. The new tab page of Firefox 57 comes with a search bar, top sites, Highlights and snippets. Highlights is a special section of the new tab page which extends top sites you visit. It represents them in a fancy way. If you are unhappy to see them, you can quickly disable them.