Examine source code of FF Logo On The Panel

{
  "manifest_version": 3,
  "name": "FF Logo On The Panel",
  "version": "1.0",
  "description": "Shows the FF logo in the panel.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "48": "icons/firefox.png"
    }
  },
  "icons": {
    "48": "icons/firefox.png"
  },
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "fflogo.realgrandrew@gmail.com"
    }
  }
}