Examine source code of Grey Clouds Drawing

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "Grey Clouds Drawing",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "center top"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(8, 50, 50)",
      "toolbar_text": "rgb(191, 246, 225)",
      "frame": "rgb(2, 41, 41)",
      "tab_background_text": "rgb(204, 251, 232)",
      "toolbar_field": "rgb(3, 38, 30)",
      "toolbar_field_text": "rgb(206, 249, 232)",
      "tab_line": "rgb(0, 0, 0)",
      "popup": "rgb(0, 58, 44)",
      "popup_text": "rgb(154, 232, 207)",
      "tab_loading": "rgb(0, 0, 0)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{a98d8269-dcbd-49ca-a15a-9236f9e02869}"
    }
  }
}