Examine source code of GrenGren

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "GrenGren",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-013-06591d4ad28ab7b9ee90f62f81d6b505.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(42, 57, 42)",
      "toolbar_text": "rgb(255, 255, 255)",
      "frame": "rgb(28, 36, 27)",
      "tab_background_text": "rgb(217, 239, 215)",
      "toolbar_field": "rgb(61, 89, 54)",
      "toolbar_field_text": "rgb(255, 255, 255)",
      "tab_line": "rgb(126, 226, 123)",
      "popup": "rgb(31, 61, 33)",
      "popup_text": "rgb(215, 239, 216)",
      "tab_loading": "rgb(126, 226, 123)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{15bef50d-f708-4d0c-b96d-c99195af43cd}"
    }
  }
}