Examine source code of Watermark Remover

{
  "manifest_version": 2,
  "name": "Watermark Remover",
  "version": "1.0",
  "description": "Select and blur watermarks on images manually.",
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_title": "Remove Watermark",
    "default_popup": "popup.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{ef41988e-de8c-4827-985a-e20ba1f67ab9}"
    }
  }
}