The snap_software_description plugin is used by websites that offer files for download. The descriptions are saved in an XML file format (see format here) and can be downloaded by robots to promote your files on their own websites. The idea of the Snap Software Description plugin is based on the PAD File format, only very much enhanced to support modern software definitions.
The plugin actually also creates PAD Files to be compatible with existing systems. However, these are somewhat limited and much of the data will be dropped.