Examine source code of Ancient One Dark

{
  "manifest_version": 2,
  "version": "1.2",
  "name": "Ancient One Dark",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.png"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(49, 42, 78)",
      "toolbar_text": "rgb(213, 208, 222)",
      "frame": "rgb(25, 21, 42)",
      "tab_background_text": "rgb(171, 165, 189)",
      "toolbar_field": "rgb(61, 54, 91)",
      "toolbar_field_text": "rgb(228, 223, 235)",
      "tab_line": "rgb(254, 201, 85)",
      "popup": "rgb(49, 42, 78)",
      "popup_text": "rgb(211, 207, 219)",
      "popup_border": "rgb(75, 64, 118)",
      "tab_loading": "rgb(254, 201, 85)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{2d293184-dab7-4665-bd16-f702c9b273b2}"
    }
  }
}