TIdCookieRFC2965 = class(TIdCookieRFC2109);

TIdCookieRFC2965 is a TIdCookieRFC2109 descendant that implements a persistent session mechanism using Cookies in HTTP requests and responses, as described in the Internet Standards document: 

RFC 2965 - HTTP State Management Mechanism  

TIdCookieRFC2965 extends TIdCookieRFC2109 by adding additional extended Cookie headers, and allows additional Cookie attributes to be indicated in the CommentURL, Discard, and PortList properties. 

TIdCookieRFC2965 differs from the original Netscape Cookie proposal, but can interoperate with HTTP/1.0 clients that use the Netscape Cookie mechanism. The significant differences in TIdCookieRFC2965 are the ability to formulate extended Cookie headers that contain MaxAge, Discard, and PortList attribute values.