Examine source code of FirstPage

{
  "manifest_version": 2,
  "name": "FirstPage",
  "version": "1.1.2.4",
  "description": "Replaces the default new tab with a customizable page with shortcuts to frequently used URLs.",
  "author": "Ismail Ataman",
  "icons": {
    "128": "./icons/logo_128.png"
  },
  "browser_action": {
    "default_icon": "./icons/logo_128.png",
    "default_title": "Add current tab to FirstPage"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "chrome_settings_overrides": {
    "homepage": "index.html"
  },
  "permissions": [
    "topSites",
    "tabs",
    "activeTab",
    "storage",
    "unlimitedStorage",
    "<all_urls>"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "ismail.ataman@gmail.com"
    }
  }
}