A file with an .ai extension is an Adobe Illustrator Artwork file that contains vector graphics on a single page. It uses points to create paths for displaying the image data, thus making it safe from losing image quality if it is enlarged. AI format finds its major usage for logos and print media. AI files can be opened with Adobe Illustrator, Adobe Acrobat DC, PaintShop Pro, and CorelDraw Graphics tools.
Text files created with Markdown language dialects is saved with .MD or .MARKDOWN file extension. MD files are saved in plain text format that uses Markdown language which also includes inline text symbols, defining how a text can be formatted such as indentations, table formatting, fonts, and headers. MD files can be converted to HTML with a program called Markdown. Markdown language is released by John Gruber.
You can also convert AI into many other file formats. Please see the complete list below.