Examine source code of Medieval 2

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Medieval 2",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(28, 32, 34, 0)",
      "toolbar_text": "rgb(250, 227, 191)",
      "frame": "rgb(19, 13, 19)",
      "tab_background_text": "rgb(222, 191, 172)",
      "toolbar_field": "rgba(161, 167, 179, 0.23)",
      "toolbar_field_text": "rgb(251, 241, 221)",
      "tab_line": "rgb(227, 218, 187)",
      "popup": "rgb(44, 34, 47)",
      "popup_text": "rgb(251, 250, 236)",
      "icons": "rgb(250, 238, 175)",
      "tab_loading": "rgb(227, 218, 187)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bd17efd8-851e-4895-9708-f2c03fa09a9f}"
    }
  }
}