Examine source code of Phone Number Hunter

{
  "manifest_version": 2,
  "name": "Phone Number Hunter",
  "version": "1.2",
  "description": "The Phone Number Hunter extension is your essential tool for effortlessly finding and compiling every phone number on any web page with a single click.",
  "icons": {
    "48": "icons/border-48.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "@phone_number_hunter",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "browser_action": {
    "default_icon": "icons/beasts-32.png",
    "default_title": "Phone Number Hunter",
    "default_popup": "popup/phone_finder.html"
  }
}