Examine source code of SimplesimpleCalculator

{
  "manifest_version": 3,
  "name": "Simple Calculator",
  "version": "1.0.0",
  "description": "A lightweight calculator extension for Firefox. Perform basic math operations directly from your toolbar.",
  "permissions": [],
  "browser_specific_settings": {
    "gecko": {
      "id": "simple-calculator@mozilla.example.com",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/icon-16.png",
      "48": "images/icon-48.png",
      "128": "images/icon-128.png"
    },
    "default_title": "Simple Calculator"
  },
  "icons": {
    "16": "images/icon-16.png",
    "48": "images/icon-48.png",
    "128": "images/icon-128.png"
  }
}