Examine source code of Nebula New Tab

{
  "manifest_version": 2,
  "name": "Nebula New Tab",
  "short_name": "Nebula",
  "version": "1.1.0",
  "version_name": "1.1.0",
  "description": "A clean and simple new tab page",
  "author": "H. Kamran",
  "developer": {
    "name": "H. Kamran",
    "url": "https://hkamran.com"
  },
  "icons": {
    "16": "assets/icons/logo16.png",
    "32": "assets/icons/logo32.png",
    "48": "assets/icons/logo48.png",
    "96": "assets/icons/logo96.png",
    "128": "assets/icons/logo128.png"
  },
  "browser_action": {
    "default_title": "Nebula New Tab",
    "default_icon": {
      "16": "assets/icons/logo16.png",
      "32": "assets/icons/logo32.png"
    }
  },
  "background": {
    "scripts": [
      "browser-polyfill.js",
      "background.js"
    ]
  },
  "chrome_url_overrides": {
    "newtab": "index.html"
  },
  "web_accessible_resources": [
    "assets/*",
    "*.js.map"
  ],
  "permissions": [
    "storage",
    "topSites"
  ],
  "browser_specific_settings": {
    "gecko": {
      "strict_min_version": "52.0a1"
    }
  },
  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self';"
}