Error Handler: Throw - Configuring custom error types

I’m looking to generate distinct error categories via the “Error Handler - Throw” action (e.g. Business Exceptions vs System Exceptions). “Error handler - Throw” seems to be built for this use case - there’s a dropdown where we can select error type. However I can’t find any options in the product or on the docs pages about how to add/manage error types. There’s only one option available originally (AllErrors).