Examine source code of Volume Booster Pro

{
  "manifest_version": 3,
  "name": "Volume Booster Pro",
  "version": "1.0.0",
  "description": "Boost audio volume up to 1000% with per-tab, per-site, or global settings. Features bass boost, stereo balance, and mono mixing.",
  "browser_specific_settings": {
    "gecko": {
      "id": "volume-booster@alican.ozturk505.gmail.com",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "developer": {
    "name": "Alican Öztürk",
    "url": "https://github.com/alztrk"
  },
  "permissions": [
    "storage",
    "activeTab"
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": "icons/icon.svg"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_start"
    }
  ],
  "icons": {
    "16": "icons/icon.svg",
    "32": "icons/icon.svg",
    "48": "icons/icon.svg",
    "128": "icons/icon.svg"
  }
}