Examine source code of Justbase.fm

{
  "theme": {
    "images": {
      "theme_frame": "firefoxbanner.jpg"
    },
    "colors": {
      "frame": "#d41b1b",
      "tab_background_text": "#d42626"
    }
  },
  "version": "2.0",
  "name": "Justbase.fm",
  "manifest_version": 2,
  "description": "Banner von <a href=\"https://outgoing.prod.mozaws.net/v1/9a165ead38994ca1350acbc4813f97a9376bc10cd9a15957fb08710cc6d1d21a/http%3A//Justbase.fm\" rel=\"nofollow\">Justbase.fm</a>"
}