Extended field that was found or created.
Extended field namespace.
Extended fields created by site collaborators or 3rd-party apps
are automatically assigned to the custom namespace.
Extended field key.
When accessing contact data,
extended field data is available at extendedFields[key].
For example, if the key is "custom.notes",
the value can be accessed at extendedFields["custom.notes"].
key is generated when the extended field is created
and cannot be modified, even if displayName changes.
Display name shown in the Contact List.
Type of data the field holds.
Indicates whether the extended field is a system field or custom field.
Date and time the field was created.
Date and time the field was last updated.
Field description, if the field is a system field.