ArcGIS Server 10.7.1: What does the “web-tier authentication” and “ArcGIS Serve authentication” precisely refer to?

[JamalNUMAN]

ArcGIS Server 10.7.1: What does the “web-tier authentication” and “ArcGIS Serve authentication” precisely refer to?

I couldn’t make a distinction between “web-tier authentication” and “ArcGIS Serve authentication” terms. Can we use these two terms interchangeably?

[DanPatterson]

Control access in ArcGIS Server—ArcGIS Server | Documentation for ArcGIS Enterprise 

Web-tier authentication—ArcGIS Server | Documentation for ArcGIS Enterprise 

This stuff? it is on different help topics.  Pick according to your version

[JamalNUMAN]

Thanks Dan.

The available documents don’t provide significant answer to my question