Examine source code of YTM Mini

{
  "manifest_version": 2,
  "name": "YTM Mini",
  "description": "A lightweight mini-player for YouTube Music. Control playback, search, view your queue, and visualize audio from a popup.",
  "version": "2.0.0",
  "short_name": "YTM Mini",
  "icons": {
    "16": "icons/icon16.png",
    "48": "icons/icon48.png",
    "128": "icons/icon128.png"
  },
  "permissions": [
    "tabs",
    "storage",
    "https://music.youtube.com/*",
    "https://i.ytimg.com/*",
    "https://yt3.googleusercontent.com/*",
    "https://lh3.googleusercontent.com/*",
    "https://ytm-mini.roie.workers.dev/*"
  ],
  "optional_permissions": [
    "https://lrclib.net/*"
  ],
  "content_security_policy": "script-src 'self'; object-src 'self'; connect-src 'self' https://music.youtube.com https://i.ytimg.com https://yt3.googleusercontent.com https://lh3.googleusercontent.com https://ytm-mini.roie.workers.dev wss://ytm-mini.roie.workers.dev https://lrclib.net;",
  "browser_specific_settings": {
    "gecko": {
      "id": "{9e1f72ca-ab0c-4ab2-be9a-80dce8fcefe3}",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "commands": {
    "_execute_browser_action": {
      "suggested_key": {
        "default": "Alt+Y",
        "mac": "Alt+Y"
      }
    }
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "browser_action": {
    "default_title": "YTM Mini",
    "default_popup": "popup.html"
  }
}