Head is a procedure used to request the header values for the resource specified in URL. Head is identical to Get, except that the server does not return a message body in the Response. 

The header values returned for the Request can be found in Response. 

Head can be used to obtain metainformation about the entity implied by the request without transferring the full content of the resource. Head is often used for testing the value in URL for validity, accessibility, and recent modification.

TIdCustomHTTP.Get 

TIdCustomHTTP.Response 

TIdHTTPResponse