Examine source code of YTM Enhancer

{
  "manifest_version": 3,
  "name": "YTM Enhancer",
  "version": "0.4.1",
  "description": "Smarter controls, automation, notifications, and visual upgrades for YouTube Music",
  "permissions": [
    "activeTab",
    "alarms",
    "notifications",
    "scripting",
    "storage"
  ],
  "host_permissions": [
    "https://music.youtube.com/*",
    "https://lh3.googleusercontent.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "type": "module"
  },
  "content_scripts": [
    {
      "matches": [
        "https://music.youtube.com/*"
      ],
      "js": [
        "content.js"
      ]
    }
  ],
  "commands": {
    "play-pause": {
      "suggested_key": {
        "default": "Alt+Shift+P"
      },
      "description": "Play/pause the current track"
    },
    "next-track": {
      "suggested_key": {
        "default": "Alt+Shift+N"
      },
      "description": "Skip to the next track"
    },
    "previous-track": {
      "suggested_key": {
        "default": "Alt+Shift+B"
      },
      "description": "Go to the previous track"
    },
    "focus-ytm-tab": {
      "suggested_key": {
        "default": "Alt+Shift+Y"
      },
      "description": "Focus the YouTube Music tab"
    },
    "remind-me": {
      "suggested_key": {
        "default": "Alt+Shift+R"
      },
      "description": "Show a notification with the current track"
    }
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "ytm-enhancer@gormanity",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  }
}