Examine source code of Reverse Phone Lookup

{
  "name": "Reverse Phone Lookup",
  "version": "2.3",
  "description": "Perform completely free reverse phone lookup to get full name and location. By the CallerName.com team.",
  "permissions": [
    "storage",
    "https://callername.com/",
    "https://api.callername.com/"
  ],
  "browser_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "img/icon_x16.png",
      "32": "img/icon_x32.png",
      "48": "img/icon_x48.png",
      "128": "img/icon_x128.png"
    }
  },
  "icons": {
    "16": "img/icon_x16.png",
    "32": "img/icon_x32.png",
    "48": "img/icon_x48.png",
    "128": "img/icon_x128.png"
  },
  "manifest_version": 2,
  "browser_specific_settings": {
    "gecko": {
      "id": "addon@callername.com",
      "strict_min_version": "57.0"
    }
  }
}