https://learn.microsoft.com/en-us/dotnet/api/system.web.security.formsauthenticationticket?view=netframework-4.8.1&redirectedfrom=MSDN
FormsAuthenticationTicket Class (System.Web.Security) | Microsoft Learn
Provides access to properties and values of the ticket used with forms authentication to identify users. This class cannot be inherited.
class systemweb securitymicrosoftlearn