Examine source code of insta-snap

{
  "name": "insta-snap",
  "manifest_version": 2,
  "description": "Take screenshots by clicking on the extension icon.",
  "version": "1.0",
  "icons": {
    "128": "snap-48.png"
  },
  "background": {
    "page": "insta-snap.html",
    "persistent": true
  },
  "permissions": [
    "<all_urls>",
    "downloads"
  ],
  "browser_action": {},
  "browser_specific_settings": {
    "gecko": {
      "id": "{7275dc33-9032-4ab2-a94e-66f2ffe0e48c}"
    }
  }
}