Examine source code of Grab Scroll

{
  "name": "Simple Grab Scroll",
  "version": "1.0",
  "manifest_version": 2,
  "applications": {
    "gecko": {
      "id": "{5e9aad31-9528-4655-82ad-76e6557d71ea}"
    }
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "options_ui": {
    "page": "options.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "scroll.js"
      ],
      "all_frames": true
    }
  ],
  "icons": {
    "32": "icon32.png",
    "48": "icon48.png",
    "64": "icon64.png",
    "96": "icon96.png",
    "128": "icon128.png"
  }
}