Examine source code of Volume Booster 600%

{
  "manifest_version": 2,
  "name": "Volume Booster 600%",
  "version": "1.0",
  "description": "Boost webpage audio/video volume up to 600% using a simple slider.",
  "icons": {
    "48": "icon48.png",
    "96": "icon96.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{bd2a6e6f-96ce-4f5c-9d48-4be8232b85e5}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "activeTab",
    "tabs",
    "storage",
    "<all_urls>"
  ],
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_start",
      "all_frames": true
    }
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icon48.png",
      "96": "icon96.png"
    },
    "default_title": "Volume Booster"
  }
}