These are text files used as Markdown Documentation Files through Markdown language dialects. MD files are usually saved in plain text format including inline text symbols, defining how a text is formatted such as the indentations, its table formatting, fonts, and headers. The HTML documentation systems find MD files useful as well as source code version control because the human-readable text that are historically revised can be compared with MD files unlike binary files which cannot be compared that easily. MD files are also created for the purpose of plain text documentation authoring for easy conversion to HTML. Files using the MD extension were developed by John Gruber and are mostly used by the Markdown program from the Daring Fireball website. The readme files of a project created through the online version control system called GitHub also uses a README.md format oftentimes. MD files are categorized as developer files mostly used by Markdown, a great tool for converting text files to HTML versions so that users can create files that are easy to read and write.