Examine source code of disable audio on lock

{
  "manifest_version": 2,
  "name": "__MSG_extensionName__",
  "version": "1.0.0",
  "description": "__MSG_extensionDescription__",
  "default_locale": "en",
  "permissions": [
    "nativeMessaging",
    "scripting",
    "storage",
    "tabs",
    "<all_urls>"
  ],
  "icons": {
    "16": "assets/icons/icon-16.png",
    "32": "assets/icons/icon-32.png",
    "48": "assets/icons/icon-48.png",
    "96": "assets/icons/icon-96.png",
    "128": "assets/icons/icon-128.png"
  },
  "background": {
    "scripts": [
      "src/background.js"
    ],
    "persistent": true
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "src/page-guard.js"
      ],
      "all_frames": true,
      "run_at": "document_start",
      "world": "MAIN"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "disable-audio-on-lock@molodchyk",
      "strict_min_version": "140.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    },
    "gecko_android": {
      "strict_min_version": "142.0"
    }
  }
}