Examine source code of Disco Page

{
  "description": "Make the website your watching going on DISCO Mode",
  "manifest_version": 2,
  "name": "Disco Page",
  "version": "1.0.3",
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "2400": "icons/icon.png"
  },
  "page_action": {
    "default_icon": "icons/off.svg",
    "browser_style": true
  },
  "permissions": [
    "activeTab",
    "tabs",
    "unlimitedStorage"
  ]
}