Examine source code of FontMatch Live

{
  "manifest_version": 3,
  "name": "__MSG_extensionName__",
  "version": "1.0",
  "description": "__MSG_extensionDescription__",
  "permissions": [],
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "128": "icons/icon-128.png"
    }
  },
  "icons": {
    "128": "icons/icon-128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "montanalynejb21238@gmail.com"
    }
  }
}