Examine source code of Grid Monochrome

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Grid Monochrome",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-005-f5f3cf677b1f132c75ddc7bd319dd1fc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(0, 0, 0)",
      "toolbar_text": "rgb(166, 166, 166)",
      "frame": "rgb(134, 134, 134)",
      "tab_background_text": "rgb(0, 0, 0)",
      "toolbar_field": "rgb(100, 100, 100)",
      "toolbar_field_text": "rgb(0, 0, 0)",
      "tab_line": "rgb(233, 233, 233)",
      "popup": "rgb(177, 177, 177)",
      "popup_text": "rgb(29, 29, 29)",
      "tab_loading": "rgb(233, 233, 233)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{4428515b-0963-4160-b95b-b25819bf9428}"
    }
  }
}