Examine source code of Ashtray

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Ashtray",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(29, 29, 29, 0.15)",
      "toolbar_text": "rgb(144, 152, 155)",
      "frame": "rgb(3, 5, 6)",
      "tab_background_text": "rgb(86, 86, 86)",
      "toolbar_field": "rgba(0, 0, 0, 0.23)",
      "toolbar_field_text": "rgb(160, 165, 174)",
      "tab_line": "rgba(104, 108, 115, 0.52)",
      "popup": "rgb(48, 48, 48)",
      "popup_text": "rgb(126, 127, 140)",
      "tab_loading": "rgba(104, 108, 115, 0.52)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9d9da4b2-0a61-41ca-9d39-2fe77a588bf8}"
    }
  }
}