schemaAttributes

A list of the user attributes and their properties in your user pool. The attribute schema contains standard attributes, custom attributes with a custom: prefix, and developer attributes with a dev: prefix. For more information, see User pool attributes.

Developer-only attributes are a legacy feature of user pools, and are read-only to all app clients. You can create and update developer-only attributes only with IAM-authenticated API operations. Use app client read/write permissions instead.