Examine source code of NW - NoWatch

{
  "manifest_version": 2,
  "name": "NW - NoWatch",
  "version": "200",
  "description": "A simple stopwatcher in the popup window.",
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "64": "icon64.png",
      "128": "icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "{2ac07826-94ed-4d0e-9891-1896fdc5a126}",
      "strict_min_version": "109.0"
    }
  },
  "icons": {
    "64": "icon64.png",
    "128": "icon128.png"
  }
}