Examine source code of Firefly Serenade

{
  "manifest_version": 2,
  "version": "2.0",
  "name": "Firefly Serenade",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(18, 42, 51)",
      "toolbar_text": "rgb(234, 252, 205)",
      "frame": "rgb(22, 21, 19)",
      "tab_background_text": "rgb(216, 250, 255)",
      "toolbar_field": "rgb(28, 46, 40)",
      "toolbar_field_text": "rgb(234, 252, 205)",
      "tab_line": "rgb(178, 180, 109)",
      "popup": "rgb(28, 46, 40)",
      "popup_text": "rgb(234, 252, 205)",
      "button_background_hover": "rgb(41, 68, 61)",
      "icons_attention": "rgb(255, 217, 102)",
      "icons": "rgb(234, 252, 205)",
      "tab_loading": "rgb(178, 180, 109)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{443bf4af-0884-4c22-886b-21f936e899df}"
    }
  }
}