Examine source code of Volume Booster 500%

{
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "volumebooster500@gabri.com",
      "strict_min_version": "58.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "name": "Volume Booster 500%",
  "version": "1.0.5",
  "description": "Boost audio volume up to 500% on any website",
  "permissions": [
    "activeTab",
    "storage",
    "tabs"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon16.png",
      "32": "icon32.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_end"
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "icons": {
    "16": "icon16.png",
    "32": "icon32.png",
    "48": "icon48.png",
    "128": "icon128.png"
  }
}