Examine source code of Rock am Ring

{
  "theme": {
    "images": {
      "theme_frame": "RockamRing.png"
    },
    "colors": {
      "frame": "#292e30",
      "tab_background_text": "#0bb6c2"
    }
  },
  "version": "2.0",
  "name": "Rock am Ring",
  "manifest_version": 2,
  "description": "Rock am Ring is the biggest Rockfestival in germany."
}