Examine source code of Cookies Facebook

{
  "browser_action": {
    "browser_style": true,
    "default_title": "List cookies in the active tab",
    "default_popup": "cookies.html",
    "default_icon": {
      "19": "icons/default19.png",
      "38": "icons/default38.png"
    }
  },
  "description": "List cookies in the active tab.",
  "icons": {
    "48": "icons/cookie.png",
    "96": "icons/cookie@2x.png"
  },
  "homepage_url": "https://github.com/mdn/webextensions-examples/tree/master/list-cookies",
  "manifest_version": 2,
  "name": "List cookies",
  "version": "1.1resigned1",
  "permissions": [
    "cookies",
    "<all_urls>",
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{1417cc02-4648-4462-9052-a40dc1f70c24}"
    }
  }
}