Alter taxonomy_term definition to add proper properties ?

Hi all, I need your help. Have you already try to add an element in definition of an entity like ‘translatable’ but for exports eg : ‘is_exportable, My need is to add this information in all exports of my taxonomy_vocabulary with that information I imagine to add a handler in Taxonomy entity ‘export’ and have acces to this in routes eg : $entity->is_exportable(); This is possible in your opinion or I in wrong (obscure) way ?