Examine source code of Fairy Ring Night

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Fairy Ring Night",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(13, 13, 26, 0)",
      "toolbar_text": "rgb(230, 230, 255)",
      "frame": "rgb(31, 51, 80)",
      "tab_background_text": "rgb(187, 187, 204)",
      "toolbar_field": "rgba(26, 26, 46, 0.37)",
      "toolbar_field_text": "rgb(240, 240, 255)",
      "tab_line": "rgb(66, 100, 182)",
      "popup": "rgb(31, 51, 80)",
      "popup_text": "rgb(230, 230, 255)",
      "tab_loading": "rgb(66, 100, 182)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{0416bb5f-9ed2-45ea-88d2-64b34505c3af}"
    }
  }
}