Labels are annotation tagged on to the publication references. They can be used to denote e.g. which facility unit or research group was involved in a publication, or what area the publication is in. The set of labels are controlled by the site admin.
A curator account can have privileges for a set of labels. This means that she can add or remove those labels to a publication. She cannot change the labels for which she does not have privileges.
Labels may have qualifiers, which can be used to denote e.g. what type of involvement a facility unit had with the publication. The available qualifiers are part of the configuration of a site and cannot be changed via the web interface.