explain setup for front-end elements

[Lukas113]

I've looked through the dev-guide and the ontology and I haven't seen an explanation how to set up front-end elements like drop-downs or radio-buttons. I've also looked into some active service-notebooks like desi-legacy-survey how a drop-down is done. However, if I'm looking at the data_release drop-down of MMODA DESI LegacySurvey, I just see data_release=9 # http://odahub.io/ontology#Integer in the notebook. In addition, the drop-down values on the front-end are not just integer-values, but DR{number} values.

So to me it looks like the features are available, but I just haven't found the according documentation or it doesn't exist. Is this just something which I can customize when connecting to the MMODA frontend?