Examine source code of Tab Media Play/Pause

{
  "manifest_version": 2,
  "name": "Tab Media Play/Pause",
  "version": "0.1",
  "description": "Adds a context menu item to play or pause media on the selected tab, making media control more convenient across multiple tabs",
  "background": {
    "scripts": [
      "background-script.js"
    ]
  },
  "permissions": [
    "menus",
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{bbe7eb51-eb71-41e3-84f2-9ff1fa467fd4}"
    }
  }
}