Examine source code of On The Moon

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "On The Moon",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(42, 34, 43)",
      "toolbar_text": "rgb(163, 165, 147)",
      "frame": "rgb(253, 233, 164)",
      "tab_background_text": "rgb(42, 34, 43)",
      "toolbar_field": "rgb(32, 17, 36)",
      "toolbar_field_text": "rgb(238, 241, 215)",
      "tab_line": "rgb(42, 34, 43)",
      "popup": "rgb(42, 34, 43)",
      "popup_text": "rgb(238, 241, 215)",
      "tab_loading": "rgb(42, 34, 43)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{7c9e1588-f9ea-48bd-81b4-ecb24384d0e6}"
    }
  }
}