According to the post, community member Kapa suggests that to know which metadata is automatically selected and used in generating the response, one would need to modify the VectorIndexAutoRetriever or the underlying LlamaIndex code. In the comments, another community member notes that this information is also included in the logs, providing a link to the relevant code.
From Kapa: "If you want to know which metadata is automatically selected and used in generating the response, you would need to modify the VectorIndexAutoRetriever or the underlying LlamaIndex code to return this information."