It uses existing Knowledge Base search source and uses RAG Retrieval.

Email response uses it from search_profile:

instance-name.service-now.com/ais_search_profile.do?sys_id=6699a4ff3b72021089392a60c5e45a0d

You can access OOB KB indexed source and search source in instance by:

instance-name.service-now.com/ais_datasource.do?sys_id=975c0985772300102d71af6168106191

instance-name.service-now.com/ais_search_source.do?sys_id=64ce118dc30101103f4fcd7b7940dd10