An MD file is a plain-text document written in Markdown — headings, lists, links and code marked up with simple symbols instead of formatting buttons. Any text editor can open one, but to read it the way the author intended, drop the .md file onto a viewer and it renders as a formatted page right in your browser, with nothing uploaded.
Open the viewer — drag in your .md file →Markdown is plain text, so an MD file stays readable forever: no proprietary format, no version lock-in, tiny file sizes, and it diffs cleanly — which is why GitHub, GitLab and most developer documentation use it for README files, and why note apps and static-site generators store everything as .md. Opening one is easy in two modes: for editing, any text editor (Notepad, TextEdit, VS Code) shows the raw markup; for reading, raw symbols like # and ** get in the way, so a renderer turns them into headings, tables and highlighted code. This viewer parses the file locally in your tab — a 10 MB README renders as fast as a short one, works with the network switched off after first load, and never sends your document anywhere.
.md / README.md file onto the drop zone (or click to browse).