Examine source code of FakeUpdate

{
  "manifest_version": 2,
  "name": "FakeUpdate",
  "version": "1.0",
  "description": "Hides the screen behind a fake Windows 10 Update, taken from www.updatefaker.com",
  "homepage_url": "https://www.updatefaker.com/",
  "icons": {
    "48": "icons/icon_48.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "activeTab",
    "webRequest"
  ],
  "browser_action": {
    "default_icon": "icons/icon_32.png"
  }
}