\ProvidesFile{iso-alphabetic.dbx} [2022/03/20 v0.4.1 ISO 690 biblatex data model extension] \RequireBiber[3] % Declare new fields \DeclareDatamodelFields[type=list, datatype=name]{supervisor} \DeclareDatamodelFields[type=field, datatype=literal]{dateaddon} % Declare new fields for (specific / all) entry types \DeclareDatamodelEntryfields[thesis]{supervisor} \DeclareDatamodelEntryfields{dateaddon}