Examine source code of Radio Widget

{
  "manifest_version": 3,
  "name": "Radio Widget",
  "short_name": "Radio Widget",
  "version": "1.0.0",
  "description": "35,000+ public radio stations. Persistent browser widget — lightweight, private, no tracking.",
  "author": "rheysoft",
  "default_locale": "en",
  "icons": {
    "16": "icons/icon-16.png",
    "32": "icons/icon-32.png",
    "48": "icons/icon-48.png",
    "128": "icons/icon-128.png"
  },
  "action": {
    "default_title": "Open Radio Widget",
    "default_icon": {
      "16": "icons/icon-16.png",
      "32": "icons/icon-32.png"
    }
  },
  "sidebar_action": {
    "default_panel": "src/panel/panel.html",
    "default_title": "Radio Widget",
    "default_icon": "icons/icon-48.png"
  },
  "background": {
    "scripts": [
      "src/background/sw.js"
    ],
    "type": "module"
  },
  "permissions": [
    "storage",
    "alarms"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "radio-widget@rheysoft.com",
      "strict_min_version": "109.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "commands": {
    "play-pause": {
      "suggested_key": {
        "default": "MediaPlayPause"
      },
      "description": "Play / Pause radio"
    },
    "next-station": {
      "suggested_key": {
        "default": "MediaNextTrack"
      },
      "description": "Next station"
    },
    "prev-station": {
      "suggested_key": {
        "default": "MediaPrevTrack"
      },
      "description": "Previous station"
    }
  },
  "content_security_policy": {
    "extension_pages": "default-src 'self'; media-src *; connect-src https://radio-browser.info https://*.radio-browser.info https://api.gumroad.com; img-src http: https: data: blob:; style-src 'self'; font-src 'self'"
  }
}