Examine source code of Halloween/Autumn

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Halloween",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(51, 0, 91)",
      "toolbar_text": "rgb(253, 140, 0)",
      "frame": "rgb(0, 3, 4)",
      "tab_background_text": "rgb(205, 55, 232)",
      "toolbar_field": "rgb(64, 0, 120)",
      "toolbar_field_text": "rgb(253, 140, 0)",
      "tab_line": "rgb(244, 148, 41)",
      "popup": "rgb(76, 24, 116)",
      "popup_text": "rgb(244, 148, 41)",
      "popup_highlight": "rgb(205, 55, 232)",
      "sidebar_highlight_text": "rgb(253, 140, 0)",
      "toolbar_field_border_focus": "rgb(253, 140, 0)",
      "toolbar_field_border": "rgb(253, 140, 0)",
      "toolbar_field_highlight": "rgb(155, 87, 3)",
      "toolbar_field_separator": "rgb(253, 140, 0)",
      "tab_loading": "rgb(244, 148, 41)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{b0e5b02f-2015-40a5-b1ae-60ca33c6e6e6}"
    }
  }
}