Examine source code of Paint tiles

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Paint tiles",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center center"
      ],
      "additional_backgrounds_tiling": [
        "no-repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(255, 116, 108)",
      "toolbar_text": "rgb(121, 0, 156)",
      "frame": "rgb(137, 70, 66)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 219, 210)",
      "toolbar_field_text": "rgb(132, 0, 58)",
      "tab_line": "rgb(255, 210, 252)",
      "popup": "rgb(255, 233, 199)",
      "popup_text": "rgb(132, 0, 58)",
      "tab_loading": "rgb(255, 210, 252)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9ef38bbc-57fa-4e3b-9db0-e41e5951747c}"
    }
  }
}