In some projects it may be the case that the Gerrit instance has been configured with customised review categories, for example to meet more stringent internal/external PA requirements than the default "code-review" and "verified". The Gerrit plugin for Jenkins is hard-coded to allow review of only the two default categories, and therefore cannot integrate with any such customised instance.
The proposed improvement would be to retrieve the list of available categories for the selected Gerrit instance, and allow the plugin to be configured to update any of them.
The list of available review categories can be retrieved from the Gerrit SSH CLI with the command "ssh -p <port> <host> gerrit approve --help". The output of this command can be parsed to provide the plugin configuration options.