This document discusses common file formats and codecs used on the web. It explains that file extensions determine how web servers and browsers handle files. Common text formats supported by browsers include HTML, XML, SVG, and JSON, while common image formats are SVG, BMP, JPG, PNG, and GIF. Video formats include AVI, FLV, MP4, MOV and WMV, with H.264, HEVC, VP8 and VP9 being common video codecs. Formats like Illustrator and Photoshop are not directly supported by browsers.