Examine source code of Christmas-Optional

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Christmas",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-024-8de86d890779309c9a66423c64daa480.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(130, 228, 135)",
      "toolbar_text": "rgb(0, 0, 0)",
      "frame": "rgb(223, 40, 43)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(139, 147, 19)",
      "toolbar_field_text": "rgb(222, 8, 11)",
      "tab_line": "rgb(130, 228, 135)",
      "popup": "rgb(28, 123, 204)",
      "popup_text": "rgb(139, 147, 19)",
      "button_background_active": "rgb(137, 128, 183)",
      "tab_loading": "rgb(130, 228, 135)"
    }
  }
}