httpfs depends on FUSE. It uses HTTP/1.1 extensions to read arbitrary bytes from a file on a web-server. This is particular interesting for an iso, since it can be investigated (loop device) without actually downloading the whole iso.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.