Examine source code of design_life

{
  "theme": {
    "images": {
      "theme_frame": "firefox1.jpg"
    },
    "colors": {
      "frame": "#1f0202",
      "tab_background_text": "#080808"
    }
  },
  "version": "2.0",
  "name": "design_life",
  "manifest_version": 2,
  "description": "シックな感じに作ってみました。"
}