ECCustomAttributes

Instances of ECCustomAttributeClasses that are applied to other items in a schema to add new metadata attributes. Any number of custom attributes may be applied to a schema item but only one instance of each class may be applied.

For example:

<ECProperty propertyName="LastMod" typeName="dateTime" displayLabel="Last Modified" description="The last modified time of the bis:Element.">
    <ECCustomAttributes>
        <DateTimeInfo xmlns="CoreCustomAttributes.1.0">
            <DateTimeKind>Utc</DateTimeKind>
        </DateTimeInfo>
        <HiddenProperty xmlns="CoreCustomAttributes.1.0"/>
    </ECCustomAttributes>
</ECProperty>

{
    "name" : "LastMod",
    "description" : "The last modified time of the bis:Element.",
    "isReadOnly" : true,
    "label" : "Last Modified",
    "type" : "PrimitiveProperty",
    "typeName" : "dateTime",
    "customAttributes" : [
      {
          "DateTimeKind" : "Utc",
          "className" : "CoreCustomAttributes.DateTimeInfo"
      },
      {
          "className" : "CoreCustomAttributes.HiddenProperty"
      }
    ]
},

The custom attribute concept allows any custom metadata to be applied because they are defined using a special type of ECClass, see ECCustomAttributeClass for more details