Examine source code of Extra Volume Booster

{
  "manifest_version": 2,
  "name": "Volume Booster",
  "version": "4.2.1",
  "description": "Raises the volume of quiet videos and podcasts above the player maximum.",
  "browser_specific_settings": {
    "gecko": {
      "id": "{1902ee77-1231-4493-bd8c-a85ac07ded97}",
      "strict_min_version": "101.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "icons": {
    "32": "assets/icon32.png",
    "48": "assets/icon48.png",
    "64": "assets/icon64.png",
    "96": "assets/icon96.png",
    "128": "assets/icon128.png"
  },
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_popup": "core/popup.html",
    "default_title": "Volume Booster",
    "default_icon": {
      "32": "assets/icon32.png",
      "48": "assets/icon48.png",
      "64": "assets/icon64.png",
      "96": "assets/icon96.png",
      "128": "assets/icon128.png"
    }
  },
  "web_accessible_resources": [
    "core/core.js",
    "core/content.js"
  ]
}