I also asked that question in another thread here, no reply to that one yet:
I did a quick google search afterwards for something like ‘what is reranking?’.
It seems to have something to do with receiving relevant search results and then ‘reranking’ them in order to 1) not miss relevant stuff you might have missed otherwise 2) put the more relevant results ‘at the top’.
Here was one article that was returned, it’s pretty in depth, but still gives the general idea behind it:
https://www.pinecone.io/learn/series/rag/rerankers
In regard to what this specifically means within Cursor, and why there is the option to either select embeddings OR reranker in the chat with codebase feature, I am not quite sure