Examine source code of Mono-Mixer Toggle

{
  "manifest_version": 2,
  "name": "Mono-Mixer Toggle",
  "version": "1.0",
  "description": "Toggle all browser audio output between stereo and mono.",
  "permissions": [
    "tabs",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "Toggle Mono Audio",
    "default_icon": "icon48.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "content.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "icons": {
    "48": "icon48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{9430f944-2048-4409-ad52-2309e3ee73c9}"
    }
  }
}