Examine source code of Now Playing

{
  "name": "Now Playing",
  "description": "Simple extension to automatically fetch the currently playing song from a YouTube or Spotify tab, and put it in a text or HTML file for stream widgets.",
  "manifest_version": 3,
  "version": "1.3.1",
  "icons": {
    "48": "icon.svg",
    "96": "icon.svg"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "firefox-nowplaying@suyo.be",
      "strict_min_version": "115.0"
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_title": "Start Now Playing",
    "default_icon": {
      "16": "icon.svg",
      "32": "icon.svg"
    },
    "theme_icons": [
      {
        "light": "icon-dark.svg",
        "dark": "icon.svg",
        "size": 16
      },
      {
        "light": "icon-dark.svg",
        "dark": "icon.svg",
        "size": 32
      }
    ]
  },
  "permissions": [
    "activeTab",
    "nativeMessaging",
    "notifications",
    "scripting",
    "storage"
  ]
}