With the extended information for hosts and services, you can incorporate additional information in the Web interface and also brighten up its appearance somewhat, using suitable icons. Two separate objects hold this information in Nagios 2.x:
serviceextinfo. Starting with Nagios 3.0, the additional information is defined directly in the host and service objects. Although Nagios 3.0 still evaluates the
serviceextinfo objects, it issues a warning message when checking the configuration and considers these objects to be obsolete.
It is planned to leave these out of Nagios entirely, by version 4 at the latest. Those using Nagios 3.0 for the first time should specify ...