Examine source code of Music Playback Tracker

{
  "manifest_version": 2,
  "name": "Music Playback Tracker",
  "version": "1.0",
  "description": "Track and visualize the duration of music playback from web players.",
  "permissions": [
    "activeTab",
    "storage"
  ],
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Music Tracker"
  },
  "icons": {
    "48": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "*://*/*"
      ],
      "js": [
        "popup.js"
      ],
      "run_at": "document_idle"
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{d8f10809-5f1e-40cb-9f99-8dd6b064d0a2}"
    }
  }
}