Examine source code of Rusted Grid

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Rusted Grid",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/bg-005-f5f3cf677b1f132c75ddc7bd319dd1fc.svg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(68, 54, 36)",
      "toolbar_text": "rgb(238, 154, 68)",
      "frame": "rgb(0, 0, 0)",
      "tab_background_text": "rgb(134, 100, 68)",
      "toolbar_field": "rgb(39, 40, 41)",
      "toolbar_field_text": "rgb(156, 161, 237)",
      "tab_line": "rgb(134, 77, 31)",
      "popup": "rgb(56, 57, 62)",
      "popup_text": "rgb(181, 182, 188)",
      "tab_loading": "rgb(134, 77, 31)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{f18d0fe2-7f03-4a4c-95eb-0d86363caabd}"
    }
  }
}