Examine source code of Page Sound Controller

{
  "manifest_version": 2,
  "name": "Page Sound Controller",
  "version": "1.0",
  "description": "Mute or adjust volume per tab from a simple panel.",
  "permissions": [
    "tabs",
    "storage"
  ],
  "icons": {
    "48": "icons/wave-48.png",
    "96": "icons/wave-96.png"
  },
  "browser_action": {
    "default_title": "Sound Controller",
    "default_popup": "panel/mixer-panel.html",
    "default_icon": {
      "48": "icons/wave-48.png",
      "96": "icons/wave-96.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      },
      "id": "tiany_bonfalli@outlook.com"
    }
  }
}