A concept term defines a medical coding term or OpenMRS concept dictionary term that could be mapped to a concept. A concept map connects a concept term to a concept. To understand Concepts and Mapping better, please refer to this documentation by OpenMRS: Concept Terms and Mapping (OpenMRS Wiki).
One can choose to directly add a reference term, or else, refer to a properties file key name, which will have its corresponding language translation in the property file at run time.
Here the code field of new reference term is just name
The code field of reference term Key(ETHAMBUTAL_KEY) is defined in the locale file https://github.com/Bahmni/default-config/blob/master/openmrs/i18n/clinical/locale_en.json