Examine source code of Control Tab Brightness

{
  "manifest_version": 2,
  "name": "Control Tab Brightness",
  "author": "Lakshya Gupta",
  "version": "2.0",
  "description": "Control Brightness Of Each Tab",
  "permissions": [
    "activeTab",
    "storage",
    "scripting",
    "<all_urls>"
  ],
  "browser_action": {
    "default_popup": "index.html"
  },
  "content_security_policy": "script-src 'self'; object-src 'self'",
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start"
    }
  ],
  "background": {
    "scripts": [
      "service_worker.js"
    ],
    "persistent": false
  },
  "options_ui": {
    "page": "options.html",
    "open_in_tab": true
  },
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "128": "icon128.png",
    "256": "icon256.png",
    "512": "icon512.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "tab-brightness-control@lakshyagupta-firefox-exts",
      "data_collection_permissions": {
        "required": [
          "none"
        ],
        "optional": []
      }
    }
  }
}