Examine source code of seadragon

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "seadragon",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(16, 16, 16)",
      "toolbar_text": "rgb(219, 102, 124)",
      "frame": "rgb(21, 21, 53)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(123, 127, 204)",
      "tab_line": "rgb(248, 112, 140)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(98, 102, 183)",
      "button_background_hover": "rgb(224, 66, 99)",
      "tab_loading": "rgb(248, 112, 140)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2b0e2156-5c39-4f3e-b9e0-88997c4f2a7f}"
    }
  }
}