Examine source code of WebTrack Stats

{
  "manifest_version": 2,
  "name": "Website Stats",
  "version": "1.0",
  "browser_action": {
    "default_icon": "icons/logo_64.png",
    "default_title": "Website Stats",
    "default_popup": "popup.html"
  },
  "permissions": [
    "webNavigation",
    "storage"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "description": "Show stats about which web-pages you've visited.",
  "icons": {
    "32": "icons/logo_32.png",
    "48": "icons/logo_48.png",
    "64": "icons/logo_64.png"
  },
  "applications": {
    "gecko": {
      "strict_min_version": "52.0a1",
      "id": "{af678bdb-398e-4cf7-889d-82f532f567a5}"
    }
  }
}