espocrm-base/application/Espo/Resources/metadata/fields/email.json

{
   "params":[
      {
         "name":"required",
         "type":"bool",
         "default":false
      }
   ],
   "notActualFields":[
      "data"
   ],
   "notCreatable": true,
   "filter": true,
   "fieldDefs":{
      "notStorable":true
   }
}