Examine source code of Spiderman on Firefox

{
  "theme": {
    "images": {
      "theme_frame": "SpidermanonFirefox1.jpg"
    },
    "colors": {
      "frame": "#b50202",
      "tab_background_text": "#fcdb03"
    }
  },
  "version": "2.0",
  "name": "Spiderman on Firefox",
  "manifest_version": 2,
  "description": "Spiderman climbs on Firefox!"
}