Examine source code of Music Tab

{
  "manifest_version": 2,
  "name": "Music Tab",
  "version": "1.1resigned1",
  "description": "Allows you to mute / unmute and quickly jump to and from the first tab",
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "index.js"
      ]
    }
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [
    "tabs"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{5052bf4f-df24-44dc-8b9b-f175e74a6ba6}"
    }
  }
}