Examine source code of Base64 Tool

{
  "manifest_version": 3,
  "name": "Base64 Tool",
  "version": "1.0",
  "description": "A tool for Base64 encoding and decoding. Developed by Taha Daneshmand. Contact: tahadaneshmand.2009@proton.me",
  "icons": {
    "500": "icon.png"
  },
  "action": {
    "default_icon": "icon.png",
    "default_title": "Base64 Tool",
    "default_popup": "popup.html"
  },
  "permissions": [
    "storage",
    "clipboardWrite"
  ],
  "web_accessible_resources": [
    {
      "resources": [
        "popup.js",
        "popup.css",
        "icon.png"
      ],
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "taha.daneshmande.base64tool@proton.me"
    }
  }
}