Examine source code of Scriffer

{
  "name": "Scriffer",
  "author": "Max Girkins",
  "homepage_url": "https://www.scriffer.com",
  "version": "0.5",
  "description": "Quickly annotate anything you're reading online and share it.",
  "permissions": [
    "<all_urls>",
    "*://*.scriffer.com/*",
    "*://scriffer.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "browser_action": {
    "default_icon": {
      "16": "img/icon16.png"
    }
  },
  "icons": {
    "48": "img/icon16.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "{92d4c2f7-f381-4544-a10d-f3bebdb6366d}"
    }
  }
}