Examine source code of Mountain Nature

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Mountain Chill",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(58, 89, 105, 0.17)",
      "toolbar_text": "rgb(247, 253, 251)",
      "frame": "rgb(157, 183, 190)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(90, 93, 154)",
      "tab_line": "rgb(0, 0, 255)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(90, 93, 154)",
      "tab_loading": "rgb(0, 0, 255)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{03082920-f6dd-4f2a-8812-736c77acf19c}"
    }
  }
}