Examine source code of Lineage Elf

{
  "theme": {
    "images": {
      "theme_frame": "Firefox-thema.jpg"
    },
    "colors": {
      "frame": "#000000",
      "tab_background_text": "#cbbfa8"
    }
  },
  "version": "2.0",
  "name": "Lineage Elf",
  "manifest_version": 2,
  "description": "Im not playing the game but these arts looks very intresting dont you think?"
}