Kelly put together a short video looking at z39.50 cataloging in Koha using both the basic and advanced cataloging options.
What is z39.50? Z39.50 is a client–server protocol for searching and retrieving information from remote computer databases, in short, it's a tool used for copy cataloging.
More Resources on z39.50
Monday Minutes: Adding Z39.50 Targets
Koha's New Z39.50 Responder - Item Statuses
New system preference in 18.11 AdditionalFieldsInZ3950ResultSearch
Read more by Kelly McElligott