Examine source code of This Is Halloween!!

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "This Is Halloween",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-039-717a66ba4d455686088c80f391cb3264.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(245, 158, 39)",
      "toolbar_text": "rgb(9, 186, 29)",
      "frame": "rgb(3, 37, 56)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(6, 172, 98)",
      "tab_line": "rgb(29, 27, 222)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(186, 75, 51)",
      "tab_loading": "rgb(29, 27, 222)"
    }
  }
}