Examine source code of autoScroll

{
  "name": "autoScroll",
  "version": "1.2",
  "manifest_version": 2,
  "description": "auto scroll your webpage when you are reading a long content",
  "icons": {
    "48": "icons/logo_48.png",
    "64": "icons/logo_64.png"
  },
  "browser_action": {
    "default_popup": "popup/popup.html"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content_scripts/autoScroll.js"
      ]
    }
  ],
  "web_accessible_resources": [
    "images/*.jpeg"
  ]
}