Right now the definition of locally definded data elements for MARC21 are Java classes. Yale suggested to make it configurable so libraries can create a Avram/other JSON/YAML/... configuration file which extends the predefined Java classes. The definition in configuration file is preferenced over the Java classes, so e.g. if it contains a definition of a subfield which is available in a Java class (based on LoC definition) as well, QA catalogue will use the configuration.
Right now the definition of locally definded data elements for MARC21 are Java classes. Yale suggested to make it configurable so libraries can create a Avram/other JSON/YAML/... configuration file which extends the predefined Java classes. The definition in configuration file is preferenced over the Java classes, so e.g. if it contains a definition of a subfield which is available in a Java class (based on LoC definition) as well, QA catalogue will use the configuration.