When packages are installed on the archive, some extra files are pulled out of the distribution, so that users may view more information about a package before choosing to download it.
This includes the main man page for the package, which is available both in compressed format for downloading and in HTML format for viewing in a web browser. Similarly, the README file, written by the author, is extracted and made available in its original form and as HTML.
For X windows packages, sometimes there are screen shots of the package actually running. These are stored as GIF images.