Examine source code of HeroTab

{
  "manifest_version": 2,
  "name": "HeroTab",
  "short_name": "hero-tab",
  "author": "WeHero",
  "version": "1.2.2",
  "description": "HeroTab Chrome Extension",
  "icons": {
    "16": "assets/images/icon16.png",
    "32": "assets/images/icon32.png",
    "48": "assets/images/icon48.png",
    "128": "assets/images/icon128.png"
  },
  "browser_action": {
    "default_icon": "assets/images/icon48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistence": false
  },
  "chrome_url_overrides": {
    "newtab": "newtab.html"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "web_accessible_resources": [
    "assets/*"
  ],
  "permissions": []
}