Markdown is a lightweight markup language used to format plain text. It was created so that documents could be easily written and read in plain text, while still being able to be converted to rich text (like HTML) for websites and other documents. When conversing with AI's, you can expect to get a markdown file at some point with the extension .md. The attached .txt document explains how to view a .md file on various systems. In a pinch, you may rename.md to .txt, but you will lose nice formatting when doing that.