Examine source code of WhoseIP

{
  "manifest_version": 2,
  "name": "WhoseIP",
  "version": "1.0",
  "description": "Grabs the IP address and can look up the host information",
  "icons": {
    "48": "icon48.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "com.charleysmithwth@gmail.com",
      "strict_min_version": "102.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ]
    }
  ],
  "permissions": [
    "activeTab",
    "scripting",
    "tabs"
  ],
  "background": {
    "scripts": [
      "popup.js"
    ],
    "persistent": true
  },
  "browser_action": {
    "default_icon": "icon48.png",
    "default_popup": "popup.html"
  }
}