Examine source code of Clean theme

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Yami",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-000-5672c42860d5b06e1058dc477397f3ef.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(235, 235, 235)",
      "toolbar_text": "rgb(88, 151, 223)",
      "frame": "rgb(201, 212, 222)",
      "tab_background_text": "rgb(240, 140, 40)",
      "toolbar_field": "rgb(248, 241, 211)",
      "toolbar_field_text": "rgb(118, 132, 98)",
      "tab_line": "rgb(255, 51, 51)",
      "popup": "rgb(235, 235, 235)",
      "popup_text": "rgb(255, 51, 51)",
      "tab_loading": "rgb(255, 51, 51)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{60a60331-03c7-4850-9cbb-f0c75ca21c42}"
    }
  }
}