Accessories are parts that are not further specified in the VEC (e.g. caps or locks for connectors). Those components are marked with the primaryPartType="Other" and a PartOrUsageRelatedSpecification that can be used to define which type of "accessory" it is. Common part attributes can be defined with a GeneralTechnicalPartSpecification.
A relation between PartVersion and its accessories can be established with a PartRelation in a GeneralTechnicalPartSpecification.