Examine source code of Rainy Day Goddess

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Rainy Day",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "left bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(199, 119, 158, 0)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(157, 183, 190)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgba(150, 141, 164, 0.73)",
      "toolbar_field_text": "rgb(44, 30, 63)",
      "tab_line": "rgba(218, 135, 124, 0)",
      "popup": "rgb(85, 76, 98)",
      "popup_text": "rgb(255, 255, 255)",
      "tab_loading": "rgba(218, 135, 124, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0c8043cc-8a68-4e07-89f6-025e2d1daf60}"
    }
  }
}