In software development, a README file contains information about the other files in a directory or archive of computer software.
The file’s name is generally written in uppercase. On Unix-like systems in particular, this causes it to stand out – both because lowercase filenames are more common and because the ls command commonly sorts and displays files in ASCII-code order, in which uppercase filenames will appear first.
The names could be README.md. for markdown files or README.txt for text files. Markdown is preferred due to its combination of robustness and simplicity.