Examine source code of light Concrete

{
  "manifest_version": 2,
  "version": "1.1",
  "name": "Light Concrete",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(97, 97, 97)",
      "toolbar_text": "rgb(124, 179, 243)",
      "frame": "rgb(58, 58, 58)",
      "tab_background_text": "rgb(207, 169, 130)",
      "toolbar_field": "rgb(69, 69, 69)",
      "toolbar_field_text": "rgb(140, 184, 241)",
      "tab_line": "rgb(255, 246, 51)",
      "popup": "rgb(97, 97, 97)",
      "popup_text": "rgb(255, 246, 51)",
      "tab_loading": "rgb(255, 246, 51)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{21d8ecdd-fa83-431c-8ba7-a545dcefd9eb}"
    }
  }
}