what is the best open source rag

Have you tried the CodeSplitter yet? https://docs.llamaindex.ai/en/latest/module_guides/loading/node_parsers/modules.html#codesplitter

Maybe also refer to this thread (not sure if there's been any updates on this front): https://discord.com/channels/1059199217496772688/1202221891646144542

I don't think this is open source but I found the insights interesting: https://news.ycombinator.com/item?id=39604961