Examine source code of Password Toggler PRO

{
  "name": "Password Toggler Pro",
  "version": "2.1",
  "author": "Biraj Mainali",
  "manifest_version": 2,
  "description": "Password Toggler Pro, easily hide and show your passwords",
  "icons": {
    "16": "icon.png",
    "48": "icon.png",
    "128": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "main.js"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{e2cdcb43-c38b-46e3-b149-acc910a55234}"
    }
  }
}