Examine source code of Hotaru Rabbit〜蛍うさぎ

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Hotaru Rabbit〜蛍うさぎ",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg",
        "images/1.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top",
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat",
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgba(255, 255, 255, 0.2)",
      "toolbar_text": "rgb(214, 189, 255)",
      "frame": "rgb(247, 242, 255)",
      "tab_background_text": "rgb(214, 189, 255)",
      "toolbar_field": "rgba(255, 255, 255, 0.2)",
      "toolbar_field_text": "rgb(158, 125, 212)",
      "tab_line": "rgb(214, 189, 255)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(158, 125, 212)",
      "tab_loading": "rgb(214, 189, 255)"
    }
  }
}