We can find Sitecore.Owin.Authentication.Enabler.config configuration file in
App_Config\Include\Examples folder to enable Federated authentication in Sitecore version 8.2. We just need to remove .example from the end of the file.
But when i tried to find out this configuration file in Sitecore 9.1, i was not able to find out this file.
I know that Sitecore 9.1 introduced Sitecore Identity (SI) to provides a separate identity provider, and allows user to set up SSO (Single Sign-On) across Sitecore services and applications.
Sitecore also mentioned that it does not support the Active Directory integration, and for that we should use federated authentication instead.
Now the question is, how to use or enable federated authentication if we don't find Sitecore.Owin.Authentication.Enabler.config file?