Examine source code of Tabify - A mini Spotify

{
  "version": "2.0.5",
  "manifest_version": 3,
  "name": "Spotify on tab: A mini Spotify player",
  "permissions": [
    "notifications",
    "offscreen"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{a79cf969-885f-46b3-a111-e108c2ab95f0}"
    }
  },
  "action": {
    "default_title": "Spotify player on your tab",
    "default_popup": "player.html"
  },
  "options_ui": {
    "page": "option.html",
    "open_in_tab": true
  },
  "icons": {
    "32": "images/32.png",
    "64": "images/64.png",
    "128": "images/128.png",
    "256": "images/256.png"
  },
  "content_scripts": [
    {
      "js": [
        "authorized.bundle.js"
      ],
      "matches": [
        "https://pnlpal.dev/spotify-on-browser*",
        "https://pnl.dev/spotify-on-browser*"
      ]
    }
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "authorized.html"
      ],
      "matches": [
        "https://pnlpal.dev/*",
        "https://pnl.dev/*"
      ]
    }
  ],
  "commands": {
    "toggle-feature-previous": {
      "suggested_key": {
        "default": "Ctrl+Shift+7"
      },
      "global": true,
      "description": "Play previous track"
    },
    "toggle-feature-play": {
      "suggested_key": {
        "default": "Ctrl+Shift+8"
      },
      "global": true,
      "description": "Play or pause"
    },
    "toggle-feature-next": {
      "suggested_key": {
        "default": "Ctrl+Shift+9"
      },
      "global": true,
      "description": "Play next track"
    },
    "toggle-feature-save": {
      "suggested_key": {
        "default": "Ctrl+Shift+0"
      },
      "global": true,
      "description": "Like the track"
    }
  }
}