You currently limit to html, word documents and text files. .md is the market for MARKDOWN which all AI know perfectly well and that is essentially a text file - with the exception that you use a different extesion to, you know, redirect to a different editor. The ability to upload .md files would make it a lot easier to deal with structured documents. Obviously, MD formatting could also help with chunking. AT the worst case (and it works amazingly well), it would be trivial to allow a .md file extension for documents. I just moved all my files (which have AWLAYS been markdown) - in the past that worked perfectly, now I cna not upload them, but the fact that they worked (as markdown) in the past means.... it really runs down to allowing the .md extension without any additional code change.